Cilostazol for peripheral arterial disease - a position paper from the Italian Society for Angiology and Vascular Medicine

Cilostazol is a quinolinone-derivative selective phosphodiesterase inhibitor and is a platelet-aggregation inhibitor and arterial vasodilator for the symptomatic treatment of intermittent claudication (IC). Cilostazol has been shown to improve walking distance for patients with moderate to severe disabling intermittent claudication who do not respond to exercise therapy and who are not candidates for vascular surgical or endovascular procedures. Several studies evaluated the pharmacological effects of cilostazol for restenosis prevention and indicated a possible effect on re-endothelialization mediated by hepatocyte growth factor and endothelial precursor cells, as well as inhibiting smooth muscle cell proliferation and leukocyte adhesion to endothelium, thereby exerting an anti-inflammatory effect. These effects may suggest a potential effectiveness of cilostazol in preventing restenosis and promoting the long-term outcome of revascularization interventions. This review aimed to point out the role of cilostazol in treating patients with peripheral arterial disease, particularly with IC, and to explore its possible role in restenosis after lower limb revascularization.

Mobile health technologies to improve walking distance in people with intermittent claudication

BACKGROUND

Peripheral arterial disease (PAD) is the obstruction or narrowing of the large arteries of the lower limbs, which can result in impaired oxygen supply to the muscle and other tissues during exercise, or even at rest in more severe cases. PAD is classified into five categories (Fontaine classification). It may be asymptomatic or various levels of claudication pain may be present; at a later stage, there may be ulceration or gangrene of the limb, with amputation occasionally being required. About 20% of people with PAD suffer from intermittent claudication (IC), which is muscular discomfort in the lower extremities induced by exertion and relieved by rest within 10 minutes; IC causes restriction of movement in daily life. Treatment for people with IC involves addressing lifestyle risk factors. Exercise is an important part of treatment, but supervised exercise programmes for individuals with IC have low engagement levels and high attrition rates. The use of mobile technologies has been suggested as a new way to engage people with IC in walking exercise interventions. The novelty of the intervention, low cost for the user, automation, and ease of access are some of the advantages mobile health (mhealth) technologies provide that give them the potential to be effective in boosting physical activity in adults.

OBJECTIVES

To assess the benefits and harms of mobile health (mhealth) technologies to improve walking distance in people with intermittent claudication.

SEARCH METHODS

The Cochrane Vascular Information Specialist conducted systematic searches of the Cochrane Vascular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and CINAHL, and also searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov. The most recent searches were carried out on 19 December 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in people aged 18 years or over with symptomatic PAD and a clinical diagnosis of IC. We included RCTs comparing mhealth interventions to improve walking distance versus usual care (no intervention or non-exercise advice), exercise advice, or supervised exercise programmes. We excluded people with chronic limb-threatening ischaemia (Fontaine III and IV).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were change in absolute walking distance from baseline, change in claudication distance from baseline, amputation-free survival, revascularisation-free survival. Our secondary outcomes were major adverse cardiovascular events, major adverse limb events, above-ankle amputation, quality of life, and adverse events. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included four RCTs involving a total of 614 participants with a clinical diagnosis of IC. The duration of intervention of the four included RCTs ranged from 3 to 12 months. Participants were randomised to either mhealth or control (usual care or supervised exercise programme). All four studies had an unclear or high risk of bias in one or several domains. The most prevalent risk of bias was in the area of performance bias, which was rated high risk as it is not possible to blind participants and personnel in this type of trial. Based on GRADE criteria, we downgraded the certainty of the evidence to low, due to concerns about risk of bias, imprecision, and clinical inconsistency. Comparing mhealth with usual care, there was no clear evidence of an effect on absolute walking distance (mean difference 9.99 metres, 95% confidence interval (CI) -27.96 to 47.93; 2 studies, 503 participants; low-certainty evidence). None of the included studies reported on change in claudication walking distance, amputation-free survival, or revascularisation-free survival. Only one study reported on major adverse cardiovascular events (MACE) and found no clear difference between groups (risk ratio 1.37, 95% CI 0.07 to 28.17; 1 study, 305 participants; low-certainty evidence). None of the included studies reported on major adverse limb events (MALE) or above-ankle amputations.

AUTHORS' CONCLUSIONS

Mobile health technologies can be used to provide lifestyle interventions for people with chronic conditions, such as IC. We identified a limited number of studies that met our inclusion criteria. We found no clear difference between mhealth and usual care in improving absolute walking distance in people with IC; however, we judged the evidence to be low certainty. Larger, well-designed RCTs are needed to provide adequate statistical power to reliably evaluate the effects of mhealth technologies on walking distance in people with IC.

Peripheral artery disease: Update on etiology, pathophysiology, diagnosis and treatment

Peripheral artery disease (PAD) is a condition related to atherosclerosis affecting >200 million people worldwide, and it increases cardiovascular morbidity (mainly from myocardial infarction and stroke) and mortality. Indeed, PAD patients are classified as patients at very high cardiovascular risk. The most common manifestation of PAD is intermittent claudication, which is associated with reduced mobility and leg pain. Nevertheless, asymptomatic PAD is the most frequent form of PAD worldwide; therefore, it remains underdiagnosed and undertreated. The major risk factors for PAD are smoking, diabetes mellitus, hyperlipidemia, hypertension, overweight/obesity, age, male sex, and black race. Hence, the first and most relevant approach in PAD treatment is lifestyle management, with measures such as smoking cessation, healthy diet, weight loss, and regular physical exercise. This should also be supported by an optimal pharmacological approach including lipid-lowering drugs, antihypertensive drugs, antidiabetic agents, and antithrombotics.

The addition of evolocumab to maximal tolerated statin therapy improves walking performance in patients with peripheral arterial disease and intermittent claudication (Evol-PAD study)

OBJECTIVE

To test the hypothesis that in patients with peripheral arterial disease (PAD) and claudication, treated with maximal tolerated statin therapy, the addition of a monthly subcutaneous injection of evolocumab for 6 months improves treadmill walking performance.

BACKGROUND

Lipid lowering therapy improves walking parameters in patients with PAD and claudication. Evolocumab decreases cardiac and limb adverse events in patients with PAD; however, the effect of evolocumab on walking performance is not known.

METHODS

We performed a double-blind, randomized, placebo-controlled study to compare maximal walking time (MWT) and pain free walking time (PFWT) in patients with PAD and claudication treated with monthly subcutaneous injections of evolocumab 420 mg (n = 35) or placebo (n = 35). We also performed measurements of lower limb perfusion, brachial flow mediated dilatation (FMD), carotid intima media thickness (IMT), and serum biomarkers of PAD disease severity.

RESULTS

After six-months of treatment with evolocumab MWT increased by 37.7 % (87.5 ± 24 s) compared to 1.4 % (-21.7 ± 22.9 s) in the placebo group, p = 0.01. PFWT increased by 55.3 % (67.3 ± 21.2 s) in the evolocumab group compared to 20.3 % (8.5 ± 20.3 s) in the placebo group, p = 0.051. There was no difference in lower extremity arterial perfusion measurements. FMD increased by 42.0 ± 73.9 % (1.01 ± 0.7 %) in the evolocumab group and decreased by 16.29 ± 20.06 % (0.99 ± 0.68 %) in the placebo group (p < 0.001). IMT decreased by 7.16 ± 4.6 % (0.06 ± 0.04 mm) in the evolocumab group and increased by 6.68 ± 4.9 % (0.05 ± 0.03 mm) in the placebo group, (p < 0.001).

CONCLUSIONS

The addition of evolocumab to maximal tolerated statin therapy improves maximal walking time in patients with PAD and claudication, increases FMD, and decreases IMT.

CONDENSED ABSTRACT

Peripheral arterial disease (PAD) impairs quality of life by causing lower extremity intermittent claudication, rest pain, or amputation. Evolocumab is a monthly injectable monoclonal antibody medication that reduces cholesterol. In this study, we randomly treated patients with PAD and claudication, and on background statin therapy, with evolocumab or placebo, and found that evolocumab improves walking performance on a treadmill test by increasing maximal walking time. We also found that evolocumab decreases plasma MRP-14 levels, a marker of PAD severity.

Real-World Safety and Effectiveness of Controlled-Release Cilostazol in Patients with Symptomatic Peripheral Artery Disease

BACKGROUND

Cilostazol is the only first-line medication for treating intermittent claudication, and the controlled-release (CR) formulation is associated with a lower prevalence of adverse events (AEs).

OBJECTIVE

The objective of the study was to assess the safety and effectiveness of cilostazol CR in patients with symptomatic peripheral artery disease (PAD).

METHODS

In this multicentre (113 sites), open-label, prospective observational study, we evaluated the real-world safety and effectiveness of cilostazol CR 200 mg once daily in patients with symptomatic PAD treated in routine clinical settings. The primary endpoint was the incidence and severity of AEs, and their causal relationship with cilostazol CR. The secondary endpoint was the effectiveness of the drug, as assessed by each patient's physician, for improving intermittent claudication.

RESULTS

Among 2063 participants who received cilostazol CR for a mean duration of 88.6 days, 99 (4.80 %) experienced adverse drug reactions (ADRs), although no unexpected adverse reactions were observed. There was no significant difference in the incidence of ADRs according to patient demographics and comorbidities (all p > 0.05). The treatment was 'effective' in 1600 patients (78.93 %), although effectiveness significantly differed according to the patients' sex and the presence of comorbidities, including diabetes mellitus, hypertension, and coronary artery disease (all p < 0.01).

CONCLUSIONS

This study demonstrated the tolerability and effectiveness of cilostazol CR treatment in patients with symptomatic PAD.

Moderate dose of dietary nitrate improves skeletal muscle microvascular function in patients with peripheral artery disease

Peripheral artery disease (PAD) is an atherosclerotic disease characterized by compromised lower-extremity blood flow that impairs walking ability. We showed that a moderate dose of dietary nitrate in the form of beetroot juice (BRJ, 0.11 mmol/kg) can improve macrovascular function and maximal walking distance in patients with PAD. However, its impacts on the microcirculation and autonomic nervous system have not been examined. Therefore, we investigated the impacts of this dose of dietary nitrate on skeletal muscle microvascular function and autonomic nervous system function and further related these measurements to 6-min walking distance, pain-free walking distance, and exercise recovery in patients with PAD. Patients with PAD (n = 10) ingested either BRJ or placebo in a randomized crossover design. Heart rate variability, skeletal muscle microvascular function, and 6-min walking distance were performed pre- and post-BRJ and placebo. There were significant group × time interactions (P < 0.05) for skeletal muscle microvascular function, 6-min walking distance, and exercise recovery, but no changes (P > 0.05) in heart rate variability or pain-free walking distance were noted. The BRJ group demonstrated improved skeletal muscle microvascular function (∆ 22.1 ± 7.5 %·min-1), longer 6-min walking distance (Δ 37.5 ± 9.1 m), and faster recovery post-exercise (Δ -15.3 ± 4.2 s). Furthermore, changes in skeletal muscle microvascular function were positively associated with changes in 6-min walking distance (r = 0.5) and pain-free walking distance (r = 0.6). These results suggest that a moderate dose of dietary nitrate may support microvascular function, which is related to improvements in walking distance and claudication in patients with PAD.

Characterizing patient-reported claudication treatment goals to support patient-centered treatment selection and measurement strategies

OBJECTIVE

Patient-reported outcomes (PRO) have been increasingly emphasized for peripheral artery disease (PAD). Patient-defined treatment goals and expectations, however, are poorly understood and might not be achievable or aligned with guidelines or clinical outcomes. We evaluated the patient-reported treatment goals among patients with claudication and the associations between patient characteristics, goals, and PAD-specific PRO scores.

METHODS

Patients with a diagnosis of claudication were prospectively recruited. Patient-defined treatment goals and outcomes related to walking distance, duration, and speed were quantified using multiple-choice survey items. Free-text items were used to identify activities other than walking distance, duration, or speed associated with symptoms and treatment goals. The peripheral artery disease quality of life and walking impairment questionnaire instruments were included as PRO. The treatment goal categories were compared with the PRO percentile scores using 95% confidence intervals (CIs), categorical tests, and logistic regression models. Associations between the patient characteristics and PRO were evaluated using linear and ordinal logistic regression models.

RESULTS

A total of 150 patients meeting the inclusion criteria were included in the present study. Of these 150 patients, 144 (96%) viewed the entire survey. Their mean age was 70.0 ± 11.3 years, and 32.9% were women. Most of the respondents had self-reported their race as White (n = 135), followed by Black (n = 3), Asian (n = 2), Native American (n = 2), and other/unknown (n = 2). Two participants self-reported Hispanic ethnicity. The primary treatment goals were an increased walking distance or duration without stopping (62.0%), the ability to perform a specific activity or task (23.0%), an increased walking speed (8.0%), or other/none of the above (7.0%). The specific activities associated with symptoms or goals included outdoor recreation (38.5%), labor-related tasks (30.7%), sports (26.9%), climbing stairs (23.1%), uphill walking (19.2%), and shopping (6%). Among the patients choosing an increased walking distance and duration as the primary goals, 64% had indicated that a distance of ≥0.5 mile (2640 ft) and 59% had indicated a duration of ≥30 minutes would be a minimum increase consistent with meaningful improvement. Increasing age was associated with lower odds of a distance improvement goal of ≥0.5 mile (odds ratio [OR], 0.68 per 5 years; 95% CI, 0.51-0.92; P = .012) or duration improvement goal of ≥30 minutes (OR, 0.76 per 5 years; 95% CI, 0.58-0.99; P = .047). Patient characteristics associated with PAD Quality of Life percentile scores included age, ankle brachial index, and gender. Ankle brachial index was the only patient characteristic associated with the walking impairment questionnaire percentile scores.

CONCLUSIONS

Patients define treatment goals according to their desired activities and expectations, which may influence their goals and perceived outcomes. Patients' expectations of minimum increases in walking distance and duration consistent with meaningful improvement exceeded reported minimum important difference criteria for many patients and would not be captured using common clinic-based walking tests. Patient age was associated with both treatment goals and PRO scores, and the related floor and ceiling effects could influence sensitivity to PRO changes for younger and older patients, respectively. Heterogeneity in treatment goals supports consideration of tailored decision-making and outcomes informed by patient characteristics and perspectives.

MetfOrmin BenefIts Lower Extremities with Intermittent Claudication (MOBILE IC): randomized clinical trial protocol

BACKGROUND

Peripheral artery disease (PAD) affects over 230 million people worldwide and is due to systemic atherosclerosis with etiology linked to chronic inflammation, hypertension, and smoking status. PAD is associated with walking impairment and mobility loss as well as a high prevalence of coronary and cerebrovascular disease. Intermittent claudication (IC) is the classic presenting symptom for PAD, although many patients are asymptomatic or have atypical presentations. Few effective medical therapies are available, while surgical and exercise therapies lack durability. Metformin, the most frequently prescribed oral medication for Type 2 diabetes, has salient anti-inflammatory and promitochondrial properties. We hypothesize that metformin will improve function, retard the progression of PAD, and improve systemic inflammation and mitochondrial function in non-diabetic patients with IC.

METHODS

200 non-diabetic Veterans with IC will be randomized 1:1 to 180-day treatment with metformin extended release (1000 mg/day) or placebo to evaluate the effect of metformin on functional status, PAD progression, cardiovascular disease events, and systemic inflammation. The primary outcome is 180-day maximum walking distance on the 6-min walk test (6MWT). Secondary outcomes include additional assessments of functional status (cardiopulmonary exercise testing, grip strength, Walking Impairment Questionnaires), health related quality of life (SF-36, VascuQoL), macro- and micro-vascular assessment of lower extremity blood flow (ankle brachial indices, pulse volume recording, EndoPAT), cardiovascular events (amputations, interventions, major adverse cardiac events, all-cause mortality), and measures of systemic inflammation. All outcomes will be assessed at baseline, 90 and 180 days of study drug exposure, and 180 days following cessation of study drug. We will evaluate the primary outcome with linear mixed-effects model analysis with covariate adjustment for baseline 6MWT, age, baseline ankle brachial indices, and smoking status following an intention to treat protocol.

DISCUSSION

MOBILE IC is uniquely suited to evaluate the use of metformin to improve both systematic inflammatory responses, cellular energetics, and functional outcomes in patients with PAD and IC.

TRIAL REGISTRATION

The prospective MOBILE IC trial was publicly registered (NCT05132439) November 24, 2021.

Systematic review the efficacy and safety of cilostazol, pentoxifylline, beraprost in the treatment of intermittent claudication: A network meta-analysis

Objective

To evaluate the efficacy and safety of cilostazol, pentoxifylline, beraprost for intermittent claudication due to lower extremity arterial occlusive disease.

Methods

Randomized controlled clinical trials were identified from PubMed, Scopus, EMbase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, SinoMed, Wanfang and Chongqing VIP databases, from the database inception to 31/12/2021. The outcome measures were walking distance measured by treadmill (maximum and pain-free walking distance), ankle-brachial index and adverse events. The quality of included studies was assessed by the Cochrane bias risk assessment tool. A network meta-analysis was carried out with Stata 16.0 software.

Results

There were 29 RCTs included in the study, covering total 5352 patients. Cilostazol was ranked first for both maximum and pain-free walking distance, followed by beraprost and pentoxifylline. For cilostazol, pentoxifylline and beraprost, maximum walking distance increased by 62.93 95%CI(44.06, 81.79), 32.72 95%CI(13.51, 55.79) and 43.90 95%CI(2.10, 85.71) meters, respectively relative to placebo, and pain-free walking distance increased by 23.92 95%CI(11.24, 36.61), 15.16 95%CI(2.33, 27.99) and 19.78 95%CI(-3.07, 42.62) meters. For cilostazol, pentoxifylline, beraprost and cilostazol combined with beraprost, ankle-brachial index increased by 0.06 95%CI(0.04, 0.07), -0.01 95%CI(-0.08, 0.05), 0.18 95%CI(0.12, 0.23) and 0.23 95%CI(0.18, 0.27), respectively relative to placebo. The pentoxifylline and cilostazol was associated with a lower ratio of adverse events than beraprost and cilostazol combined with beraprost.

Conclusion

Cilostazol, pentoxifylline and beraprost were all effective treatments for intermittent claudication; cilostazol with good tolerance was likely to be the most effective in walking distance, while beraprost and cilostazol combined with beraprost were more prominent in the ankle-brachial index.

Effects of a person-centred, nurse-led follow-up programme on adherence to prescribed medication among patients surgically treated for intermittent claudication: randomized clinical trial

BACKGROUND

Management of intermittent claudication should include secondary prevention to reduce the risk of cardiocerebrovascular disease. Patient adherence to secondary prevention is a challenge. The aim of this study was to investigate whether a person-centred, nurse-led follow-up programme could improve adherence to medication compared with standard care.

METHODS

A non-blinded RCT was conducted at two vascular surgery centres in Sweden. Patients with intermittent claudication and scheduled for revascularization were randomized to the intervention or control (standard care) follow-up programme. The primary outcome, adherence to prescribed secondary preventive medication, was based on registry data on dispensed medication and self-reported intake of medication. Secondary outcomes were risk factors for cardiocerebrovascular disease according to the Framingham risk score.

RESULTS

Some 214 patients were randomized and analysed on an intention-to-treat basis. The mean proportion of days covered (PDC) at 1 year for lipid-modifying agents was 79 per cent in the intervention and 82 per cent in the control group, whereas it was 92 versus 91 per cent for antiplatelet and/or anticoagulant agents. The groups did not differ in mean PDC (lipid-modifying P = 0.464; antiplatelets and/or anticoagulants P = 0.700) or in change in adherence over time. Self-reported adherence to prescribed medication was higher than registry-based adherence regardless of allocation or medication group (minimum P < 0.001, maximum P = 0.034). There was no difference in median Framingham risk score at 1 year between the groups.

CONCLUSION

Compared with the standard follow-up programme, a person-centred, nurse-led follow-up programme did not improve adherence to secondary preventive medication. Adherence was overestimated when self-reported compared with registry-reported.

Propionyl-L-carnitine for intermittent claudication

BACKGROUND

Peripheral arterial disease (PAD) is a manifestation of systemic atherosclerosis. Intermittent claudication is a symptomatic form of PAD that is characterized by pain in the lower limbs caused by chronic occlusive arterial disease. This pain develops in a limb during exercise and is relieved with rest. Propionyl-L-carnitine (PLC) is a drug that may alleviate the symptoms of PAD through a metabolic pathway, thereby improving exercise performance.

OBJECTIVES

The objective of this review is to determine whether propionyl-L-carnitine is efficacious compared with placebo, other drugs, or other interventions used for treatment of intermittent claudication (e.g. exercise, endovascular intervention, surgery) in increasing pain-free and maximum walking distance for people with stable intermittent claudication, Fontaine stage II.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials register to July 7, 2021. We undertook reference checking and contact with study authors and pharmaceutical companies to identify additional unpublished and ongoing studies.

SELECTION CRITERIA

Double-blind randomized controlled trials (RCTs) in people with intermittent claudication (Fontaine stage II) receiving PLC compared with placebo or another intervention. Outcomes included pain-free walking performance (initial claudication distance - ICD) and maximal walking performance (absolute claudication distance - ACD), analyzed by standardized treadmill exercise test, as well as ankle brachial index (ABI), quality of life, progression of disease, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted data, and evaluated trials for risk of bias. We contacted study authors for additional information. We resolved any disagreements by consensus. We performed fixed-effect model meta-analyses with mean differences (MDs) and 95% confidence intervals (CIs). We graded the certainty of evidence according to GRADE.

MAIN RESULTS

We included 12 studies in this review with a total number of 1423 randomized participants. A majority of the included studies assessed PLC versus placebo (11 studies, 1395 participants), and one study assessed PLC versus L-carnitine (1 study, 26 participants). We identified no RCTs that assessed PLC versus any other medication, exercise, endovascular intervention, or surgery. Participants received PLC 1 grams to 2 grams orally (9 studies) or intravenously (3 studies) per day or placebo. For the comparison PLC versus placebo, there was a high level of both clinical and statistical heterogeneity due to study size, participants coming from different countries and centres, the combination of participants with and without diabetes, and use of different treadmill protocols. We found a high proportion of drug company-backed studies. The overall certainty of the evidence was moderate. For PLC compared with placebo, improvement in maximal walking performance (ACD) was greater for PLC than for placebo, with a mean difference in absolute improvement of 50.86 meters (95% CI 50.34 to 51.38; 9 studies, 1121 participants), or a 26% relative improvement (95% CI 23% to 28%). Improvement in pain-free walking distance (ICD) was also greater for PLC than for placebo, with a mean difference in absolute improvement of 32.98 meters (95% CI 32.60 to 33.37; 9 studies, 1151 participants), or a 31% relative improvement (95% CI 28% to 34%). Improvement in ABI was greater for PLC than for placebo, with a mean difference in improvement of 0.09 (95% CI 0.08 to 0.09; 4 studies, 369 participants). Quality of life improvement was greater with PLC (MD 0.06, 95% CI 0.05 to 0.07; 1 study, 126 participants). Progression of disease and adverse events including nausea, gastric intolerance, and flu-like symptoms did not differ greatly between PLC and placebo. For the comparison of PLC with L-carnitine, the certainty of evidence was low because this included a single, very small, cross-over study. Mean improvement in ACD was slightly greater for PLC compared to L-carnitine, with a mean difference in absolute improvement of 20.00 meters (95% CI 0.47 to 39.53; 1 study, 14 participants) or a 16% relative improvement (95% CI 0.4% to 31.6%). We found no evidence of a clear difference in the ICD (absolute improvement 4.00 meters, 95% CI -9.86 to 17.86; 1 study, 14 participants); or a 3% relative improvement (95% CI -7.4% to 13.4%). None of the other outcomes of this review were reported in this study.

AUTHORS' CONCLUSIONS

When PLC was compared with placebo, improvement in walking distance was mild to moderate and safety profiles were similar, with moderate overall certainty of evidence. Although In clinical practice, PLC might be considered as an alternative or an adjuvant to standard treatment when such therapies are found to be contraindicated or ineffective, we found no RCT evidence comparing PLC with standard treatment to directly support such use.

Cilostazol for intermittent claudication

BACKGROUND

Peripheral arterial disease (PAD) affects between 4% and 12% of people aged 55 to 70 years, and 20% of people over 70 years. A common complaint is intermittent claudication (exercise-induced lower limb pain relieved by rest). These patients have a three- to six-fold increase in cardiovascular mortality.  Cilostazol is a drug licensed for the use of improving claudication distance and, if shown to reduce cardiovascular risk, could offer additional clinical benefits. This is an update of the review first published in 2007.

OBJECTIVES

To determine the effect of cilostazol on initial and absolute claudication distances, mortality and vascular events in patients with stable intermittent claudication.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and AMED databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registries, on 9 November 2020.

SELECTION CRITERIA

We considered double-blind, randomised controlled trials (RCTs) of cilostazol versus placebo, or versus other drugs used to improve claudication distance in patients with stable intermittent claudication.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for selection and independently extracted data. Disagreements were resolved by discussion. We assessed the risk of bias with the Cochrane risk of bias tool. Certainty of the evidence was evaluated using GRADE. For dichotomous outcomes, we used odds ratios (ORs) with corresponding 95% confidence intervals (CIs) and for continuous outcomes we used mean differences (MDs) and 95% CIs. We pooled data using a fixed-effect model, or a random-effects model when heterogeneity was identified. Primary outcomes were initial claudication distance (ICD) and quality of life (QoL). Secondary outcomes were absolute claudication distance (ACD), revascularisation, amputation, adverse events and cardiovascular events.

MAIN RESULTS

We included 16 double-blind, RCTs (3972 participants) comparing cilostazol with placebo, of which five studies also compared cilostazol with pentoxifylline. Treatment duration ranged from six to 26 weeks. All participants had intermittent claudication secondary to PAD. Cilostazol dose ranged from 100 mg to 300 mg; pentoxifylline dose ranged from 800 mg to 1200 mg. The certainty of the evidence was downgraded by one level for all studies because publication bias was strongly suspected. Other reasons for downgrading were imprecision, inconsistency and selective reporting. Cilostazol versus placebo Participants taking cilostazol had a higher ICD compared with those taking placebo (MD 26.49 metres; 95% CI 18.93 to 34.05; 1722 participants; six studies; low-certainty evidence). We reported QoL measures descriptively due to insufficient statistical detail within the studies to combine the results; there was a possible indication in improvement of QoL in the cilostazol treatment groups (low-certainty evidence). Participants taking cilostazol had a higher ACD compared with those taking placebo (39.57 metres; 95% CI 21.80 to 57.33; 2360 participants; eight studies; very-low certainty evidence). The most commonly reported adverse events were headache, diarrhoea, abnormal stools, dizziness, pain and palpitations. Participants taking cilostazol had an increased odds of experiencing headache compared to participants taking placebo (OR 2.83; 95% CI 2.26 to 3.55; 2584 participants; eight studies; moderate-certainty evidence).Very few studies reported on other outcomes so conclusions on revascularisation, amputation, or cardiovascular events could not be made. Cilostazol versus pentoxifylline There was no difference detected between cilostazol and pentoxifylline for improving walking distance, both in terms of ICD (MD 20.0 metres, 95% CI -2.57 to 42.57; 417 participants; one study; low-certainty evidence); and ACD (MD 13.4 metres, 95% CI -43.50 to 70.36; 866 participants; two studies; very low-certainty evidence). One study reported on QoL; the study authors reported no difference in QoL between the treatment groups (very low-certainty evidence). No study reported on revascularisation, amputation or cardiovascular events. Cilostazol participants had an increased odds of experiencing headache compared with participants taking pentoxifylline at 24 weeks (OR 2.20, 95% CI 1.16 to 4.17; 982 participants; two studies; low-certainty evidence).

AUTHORS' CONCLUSIONS

Cilostazol has been shown to improve walking distance in people with intermittent claudication. However, participants taking cilostazol had higher odds of experiencing headache. There is insufficient evidence about the effectiveness of cilostazol for serious events such as amputation, revascularisation, and cardiovascular events. Despite the importance of QoL to patients, meta-analysis could not be undertaken because of differences in measures used and reporting. Very limited data indicated no difference between cilostazol and pentoxifylline for improving walking distance and data were too limited for any conclusions on other outcomes.

Cilostazol: a Review of Basic Mechanisms and Clinical Uses

Primarily used in the treatment of intermittent claudication, cilostazol is a 2-oxyquinolone derivative that works through the inhibition of phosphodiesterase III and related increases in cyclic adenosine monophosphate (cAMP) levels. However, cilostazol has been implicated in a number of other basic pathways including the inhibition of adenosine reuptake, the inhibition of multidrug resistance protein 4, among others. It has been observed to exhibit antiplatelet, antiproliferative, vasodilatory, and ischemic-reperfusion protective properties. As such, cilostazol has been investigated for clinical use in a variety of settings including intermittent claudication, as an adjunctive for reduction of restenosis after coronary and peripheral endovascular interventions, and in the prevention of secondary stroke, although its widespread implementation for indications other than intermittent claudication has been limited by relatively modest effect sizes and lack of studies in western populations. In this review, we highlight the pleiotropic effects of cilostazol and the evidence for its clinical use.

Therapeutic Effects of Medication Use on Intermittent Claudication: A Network Meta-analysis

OBJECTIVE

To systematically evaluate the therapeutic effects of commonly used drugs for the treatment of intermittent claudication in patients with peripheral arterial diseases.

METHODS

We systematically searched bibliographic databases for randomized clinical trials published between 2000 and 2020, through the China National Knowledge Infrastructure, WanFang Data, PubMed, MEDLINE, Embase, and Cochrane library. Included studies focused on therapeutic effects of beraprost, clopidogrel, aspirin, sarpogrelate and cilostazol on treating intermittent claudication. The outcome measures were maximum walking distance, pain-free walking distance, ankle-brachial index, and severe adverse events. The quality of included trials was evaluated by using the bias risk assessment tool recommended by the Cochrane, after extracting data from the literatures. Stata was used to conduct the network meta-analysis.

RESULTS

There were 27 randomized control trials included in the study, covering in total 9491 patients. The network meta-analysis results showed that for maximum walking distance, better therapeutic effect was noted in using beraprost, sarpogrelate, and cilostazol. Beraprost, beraprost combined with aspirin, and sarpogrelate were better in improving pain-free walking distance than other drugs. For the ankle-brachial index, cilostazol combined with clopidogrel, sarpogrelate, and beraprost had better therapeutic effects than others. The use of sarpogrelate, beraprost, and aspirin was associated with a lower ratio of severe adverse events than the use of cilostazol and placebo.

CONCLUSIONS

Among the commonly used drugs for the treatment of intermittent claudication, beraprost and sarpogrelate may have better efficacy in improving the walking distance and ankle-brachial index, with a beneficial effect on cardiovascular and cerebrovascular comorbidities.

Pentoxifylline for intermittent claudication

BACKGROUND

Intermittent claudication (IC) is a symptom of peripheral arterial disease (PAD) and is associated with high morbidity and mortality. Pentoxifylline, one of many drugs used to treat IC, acts by decreasing blood viscosity, improving erythrocyte flexibility, and promoting microcirculatory flow and tissue oxygen concentration. Many studies have evaluated the efficacy of pentoxifylline in treating people with PAD, but results of these studies are variable. This is the second update of a review first published in 2012.

OBJECTIVES

To determine the efficacy of pentoxifylline in improving the walking capacity (i.e. pain-free walking distance and total (absolute, maximum) walking distance) of people with stable intermittent claudication, Fontaine stage II.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases, and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 28 January 2020. There were no language restrictions.

SELECTION CRITERIA

We included all double-blind, randomised controlled trials (RCTs) comparing pentoxifylline versus placebo or any other pharmacological intervention in people with IC Fontaine stage II.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, assessed the included studies, matched data and resolved disagreements by discussion. Review authors assessed the methodological quality of studies using the Cochrane 'Risk of bias' tool and collected results related to the outcomes of interest, pain-free walking distance (PFWD), total walking distance (TWD), ankle-brachial pressure index (ABI), quality of life (QoL) and side effects. Comparison of studies was based on duration and dose of pentoxifylline. We used GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

We identified no new eligible studies for this update. This review includes 24 studies with 3377 participants. Seventeen studies compared pentoxifylline versus placebo. The seven remaining studies compared pentoxifylline with flunarizine (one study), aspirin (one study), Gingko biloba extract (one study), nylidrin hydrochloride (one study), prostaglandin E1 (two studies), and buflomedil and nifedipine (one study). Risk of bias for the individual studies was generally unclear because there was a lack of methodological reporting for many of the included studies, especially regarding randomisation and allocation methods. Most included studies did not provide adequate information to allow selective reporting to be judged and did not report blinding of assessors. Heterogeneity between included studies was considerable with regards to multiple variables, including duration of treatment, dose of pentoxifylline, baseline walking distance and participant characteristics; therefore, pooled analysis for comparisons which included more than one study, was not possible. Pentoxifylline compared to placebo Of 17 studies comparing pentoxifylline with placebo, 11 reported PFWD and 14 reported TWD; the difference in percentage improvement in PFWD for pentoxifylline over placebo ranged from -33.8% to 73.9% and in TWD ranged from 1.2% to 155.9%. It was not possible to pool the data of the studies because data were insufficient and findings from individual trials were unclear. Most included studies suggested a possible improvement in PFWD and TWD for pentoxifylline over placebo (both low-certainty evidence). The five studies which evaluated pre-exercise ABI comparing pentoxifylline and placebo found no evidence of a difference (moderate-certainty evidence). Two of the three studies that evaluated QoL between people who received pentoxifylline and placebo were larger studies that used validated QoL tools and generally found no evidence of a difference between groups. One small, short-term study, which did not specify which QoL tool was used, reported improved QoL in the pentoxifylline group (moderate-certainty evidence). Pentoxifylline generally was well tolerated; the most commonly reported side effects consisted of gastrointestinal symptoms such as nausea (low-certainty evidence). Certainty of the evidence from this review was low or moderate, with downgrading due to risk of bias concerns, inconsistencies between studies and the inability to evaluate imprecision because meta-analysis could not be undertaken. The seven remaining studies compared pentoxifylline with either flunarizine, aspirin, Gingko biloba extract, nylidrin hydrochloride, prostaglandin E1, or buflomedil and nifedipine; data were too limited to allow any meaningful conclusions to be made.

AUTHORS' CONCLUSIONS

There is a lack of high-certainty evidence for the effects of pentoxifylline compared to placebo, or other treatments, for IC. There is low-certainty evidence that pentoxifylline may improve PFWD and TWD compared to placebo, but no evidence of a benefit to ABI or QoL (moderate-certainty evidence). Pentoxifylline was reported to be generally well tolerated (low-certainty evidence). Given the large degree of heterogeneity between the studies, the role of pentoxifylline for people with IC Fontaine class II remains uncertain.

Long-Term Effects of Bosentan on Cardiovascular Events in Hispanic Patients with Intermittent Claudication: Four-Year Follow-up of the CLAU Trial : The CLAU Randomized Trial Long-Term Outcome

INTRODUCTION

The Clinical and Endothelial Function Assessment after Endothelin Receptor Antagonist (CLAU) trial demonstrated the effect of bosentan on the endothelial function, inflammatory status and claudication distance in Hispanic patients with incipient peripheral arterial disease (PAD). Our aim was to assess the protective effect on cardiovascular events of bosentan versus conventional anti-atherosclerosis therapy.

METHODS

CLAU included 56 patients with intermittent claudication, randomized 1:1 to receive bosentan for 12 weeks (n = 27) or placebo (n = 29), associating the best medical treatment. Log-rank and hazard ratio (HR) analyses were performed to estimate the relative efficacy of bosentan in preventing incidence of major adverse events (MAE) including target limb revascularization (TLR), amputation, myocardial infarction (MI), and all-cause death; major cardiovascular adverse events (MACE) including TLR, amputation, MI, stroke, and cardiovascular-cause death; and major adverse limb events (MALE), which combines TLR and amputation.

RESULTS

During the follow-up period (34 ± 5 months), five MAE occurred in the control group only (17.2%), including two TLR, one amputation, one stroke, and an MI. The ratio of event-free survival for MAE to 3 years follow-up was higher in the group treated with bosentan (100% vs 66%, p = 0.01, HR = 76; 95% confidence interval 0.05-104,677, p = 0.24). A similar trend was observed in incidence of MACE (100% vs 66%, p = 0.01) and MALE (100% vs 80%, p = 0.15).

CONCLUSION

Treatment with bosentan in the early low-to-mild stages of PAD may prevent cardiovascular events and the need for lower limb revascularization in the Hispanic population. Trial Registration ClinicalTrials.gov identifier NCT25102012.

[Clinical study of efficacy and safety of Aducil in patients with chronic lower limb ischaemia]

AIM

The study was aimed at assessing efficacy and safety of treatment with Aducil® (cilostazol) compared with Trental® 400 in patients with moderate-to-severe intermittent claudication due to peripheral atherosclerosis.

PATIENTS AND METHODS

The study included a total of one hundred and forty-five 36-to-75-year-old patients. The participants were distributed into 2 groups according to the inclusion/exclusion criteria in a 2 to 1 proportion: patients in group 1 received Aducil® 100 mg BID, in group 2 - Trental® 400 TID for 12 weeks. 142 subjects completed the protocol.

RESULTS

Analysis of the effectiveness of treatment according to the primary criterion showed a better effectiveness of Aducil® as compared with Trental® 400. Subjects who received Aducil® had a higher increase in the absolute maximum walking distance after 12 weeks of treatment as compared with those taking Trental® 400: 126±110 m versus 45±39 m, respectively (р<0.001). Subjects who received Aducil® had a statistically significant improvement in quality of life parameters such as physical and mental health components according to the SF-36 questionnaire after 12 weeks of treatment (р≤0.01). Subjects in Aducil® group had better quality of life with an increase from 34 to 40 points according to the physical component score, while patients in Trental® 400 group demonstrated minor positive changes (from 35 to 37 points); mean mental component score increased from 45 to 48 points in Aducil® group as compared with an increase from 45 to 47 points in Trental® 400 group. While self-reported physical health status was similar between the groups at baseline, subjects in Aducil® group reported better physical functioning after treatment (р=0.016). Two adverse events were registered in two subjects in Aducil® group.

CONCLUSION

Analysis of the study endpoints demonstrated that Aducil® had better treatment effectiveness in patients with chronic lower limb ischemia stage IIB according to the classification of A.V. Pokrovsky-Fontaine as compared with Trental® 400, while the safety profile and drug tolerance were similar between the two.

Growth factors for angiogenesis in peripheral arterial disease

BACKGROUND

Peripheral artery disease (PAD) is associated with a high clinical and socioeconomic burden. Treatments to alleviate the symptoms of PAD and decrease the risks of amputation and death are a high societal priority. A number of growth factors have shown a potential to stimulate angiogenesis. Growth factors delivered directly (as recombinant proteins), or indirectly (e.g. by viral vectors or DNA plasmids encoding these factors), have emerged as a promising strategy to treat patients with PAD.

OBJECTIVES

To assess the effects of growth factors that promote angiogenesis for treating people with PAD of the lower extremities.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Specialised Register (June 2016) and CENTRAL (2016, Issue 5). We searched trial registries for details of ongoing or unpublished studies. We also checked the reference lists of relevant publications and, if necessary, tried to contact the trialists for details of the studies.

SELECTION CRITERIA

We included randomised controlled trials comparing growth factors (delivered directly or indirectly) with no intervention, placebo or any other intervention not based on the growth factor's action in patients with PAD of the lower extremities. The primary outcomes were limb amputation, death and adverse events. The secondary outcomes comprised walking ability, haemodynamic measures, ulceration and rest pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and assessed the risk of bias. We used outcomes of the studies at low risk of bias for the main analysis and of all studies in the sensitivity analyses. We calculated odds ratios (OR) for dichotomous outcomes and mean differences for continuous outcomes with 95% confidence intervals (CI). We evaluated statistical heterogeneity using the I2 statistic and Cochrane's Q test. We conducted meta-analysis for the overall effect and for each growth factor as a subgroup analysis using OR in a fixed-effect model. We evaluated the robustness of the results in a sensitivity analysis using risk ratio (RR) and/or a random-effects model. We also assessed the quality of the evidence for each outcome.

MAIN RESULTS

We included 20 trials in the review and used 14 studies (on approximately 1400 participants) with published results in the analyses. Six published studies compared fibroblast growth factors (FGF), four studies hepatocyte growth factors (HGF) and another four studies vascular endothelial growth factors (VEGF), versus placebo or no therapy. Six of these studies exclusively or mainly investigated participants with intermittent claudication and eight studies exclusively participants with critical limb ischaemia. Follow-up generally ranged from three months to one year. Two small studies provided some data at 2 years and one of them also at 10 years.The direction and size of effects for growth factors on major limb amputations (OR 0.99, 95% CI 0.71 to 1.38; 10 studies, N = 1075) and death (OR 0.99, 95% CI 0.69 to 1.41; 12 studies, N = 1371) at up to two years are uncertain. The quality of the evidence is low due to risk of bias and imprecision (at one year, moderate-quality evidence due to imprecision). However, growth factors may decrease the rate of any limb amputations (OR 0.56, 95% CI 0.31 to 0.99; 6 studies, N = 415). The quality of the evidence is low due to risk of bias and selective reporting.The direction and size of effects for growth factors on serious adverse events (OR 1.09, 95% CI 0.79 to 1.50; 13 studies, N = 1411) and on any adverse events (OR 1.10, 95% CI 0.73 to 1.64; 4 studies, N = 709) at up to two years are also uncertain. The quality of the evidence is low due to risk of bias and imprecision (for serious adverse events at one year, moderate-quality evidence due to imprecision).Growth factors may improve haemodynamic measures (low-quality evidence), ulceration (very low-quality evidence) and rest pain (very low-quality evidence) up to one year, but they have little or no effect on walking ability (low-quality evidence). We did not identify any relevant differences in effects between growth factors (FGF, HGF and VEGF).

AUTHORS' CONCLUSIONS

The results of this review do not support the use of therapy with the growth factors FGF, HGF or VEGF in people with PAD of the lower extremities to prevent death or major limb amputation or to improve walking ability. However, the use of these growth factors may improve haemodynamic measures and decrease the rate of any limb amputations (probably due to preventing minor amputations) with an uncertain effect on adverse events; an improvement of ulceration and rest pain is very uncertain. New trials at low risk of bias are needed to generate evidence with more certainty.

Effect of blood pressure lowering medications on leg ischemia in peripheral artery disease patients: A meta-analysis of randomised controlled trials

BACKGROUND

It has been suggested that anti-hypertensive medications may worsen leg ischemia in peripheral artery disease (PAD) patients. We undertook a meta-analysis to assess the effect of anti-hypertensive medications on measures of leg ischemia including maximum walking distance (MWD), pain free walking distance (PFWD) and ankle brachial pressure index (ABPI). A meta-regression was performed to evaluate whether the effect of the anti-hypertensive medications on mean arterial pressure (MAP) was associated with changes in ABPI, MWD or PFWD.

METHOD

A systematic literature search was performed to identify placebo controlled randomized control trials (RCT) testing anti-hypertensive medications, which reported baseline and follow-up measurements of: MAP and MWD, PFWD or ABPI in patients with intermittent claudication (IC) due to PAD.

RESULT

A meta-analysis was performed on 5 RCTs comprising a total of 180 and 127 patients receiving anti-hypertensive medications and placebo respectively. This analysis suggested that anti-hypertensive medication did not significantly affect MWD, PFWD or ABPI. In contrast, the meta-regression analysis showed that the reduction in MAP due to the anti-hypertensive drugs was positively correlated with increased MWD during follow-up (β = 8.371, p = 0.035). Heterogeneity across studies, as assessed by I2, was high. The follow-up period within the included trials was generally short with 3 out of 5 studies having a follow-up period of ≤ 6 weeks.

CONCLUSION

This study suggests that anti-hypertensive treatment does not worsen but may improve leg ischemia in PAD patients. Larger multicenter trials with longer anti-hypertensive treatment periods are required to clarify the effect of anti-hypertensives on leg ischemia in PAD patients.

Nonrevascularizable buttock claudication improved with Sildenafil: A case report

RATIONALE

Sildenafil, a phosphodiesterase-5-inhibitor (PDE5i), could represent a new treatment in addition to the medical treatment and advice to walk in peripheral arterial disease (PAD).

PATIENT CONCERNS AND DIAGNOSES

We report a case of a 62-year-old heavy smoker man who developed a buttock claudication and a severe walking limitation following an aorto-bi-femoral bypass in 1992. Since 2003, each year, he has been referred for investigation of bilateral buttock claudication on treadmill using transcutaneous oxygen pressure (tcpO2) measurement during exercise to argue for the vascular origin of the walking impairment. He had a severe bilateral buttock ischemia and the maximum walking distance (MWD) he reached was 258 m in 2011 despite the medical optimal treatment and walking rehabilitation. Ethical approval is not necessary for this case report according to the French legislation and written consent to publication was obtained from the patient.

INTERVENTIONS

Sildenafil, 100 mg/d, was introduced in February 2015 and the MWD increased to 310 m only after 2 h after the first oral intake, then to 713 m after 3 weeks, and finally to 1313 m in January 2017.

OUTCOMES

Recently, the patient is treated with Sildenafil 100 mg/d. He has no more pain during walking and his quality of life has improved.

MAIN LESSONS TO LEARN

Sildenafil, a PDE5i, may represent a new therapeutic option in addition to the conventional optimal medical therapy in patients with arterial claudication. tcpO2 measurement during exercise is a promising technique for the diagnosis and monitoring of patients with PAD. A crossover, double-blind, prospective randomized monocenter study (ARTERIOFIL-NCT02832570) and a double-blind prospective randomized multicenter study (VALSTAR-NCT02930811) are ongoing to confirm our original observation.

Ticagrelor versus Clopidogrel in Symptomatic Peripheral Artery Disease

BACKGROUND

Peripheral artery disease is considered to be a manifestation of systemic atherosclerosis with associated adverse cardiovascular and limb events. Data from previous trials have suggested that patients receiving clopidogrel monotherapy had a lower risk of cardiovascular events than those receiving aspirin. We wanted to compare clopidogrel with ticagrelor, a potent antiplatelet agent, in patients with peripheral artery disease.

METHODS

In this double-blind, event-driven trial, we randomly assigned 13,885 patients with symptomatic peripheral artery disease to receive monotherapy with ticagrelor (90 mg twice daily) or clopidogrel (75 mg once daily). Patients were eligible if they had an ankle-brachial index (ABI) of 0.80 or less or had undergone previous revascularization of the lower limbs. The primary efficacy end point was a composite of adjudicated cardiovascular death, myocardial infarction, or ischemic stroke. The primary safety end point was major bleeding. The median follow-up was 30 months.

RESULTS

The median age of the patients was 66 years, and 72% were men; 43% were enrolled on the basis of the ABI and 57% on the basis of previous revascularization. The mean baseline ABI in all patients was 0.71, 76.6% of the patients had claudication, and 4.6% had critical limb ischemia. The primary efficacy end point occurred in 751 of 6930 patients (10.8%) receiving ticagrelor and in 740 of 6955 (10.6%) receiving clopidogrel (hazard ratio, 1.02; 95% confidence interval [CI], 0.92 to 1.13; P=0.65). In each group, acute limb ischemia occurred in 1.7% of the patients (hazard ratio, 1.03; 95% CI, 0.79 to 1.33; P=0.85) and major bleeding in 1.6% (hazard ratio, 1.10; 95% CI, 0.84 to 1.43; P=0.49).

CONCLUSIONS

In patients with symptomatic peripheral artery disease, ticagrelor was not shown to be superior to clopidogrel for the reduction of cardiovascular events. Major bleeding occurred at similar rates among the patients in the two trial groups. (Funded by AstraZeneca; EUCLID ClinicalTrials.gov number, NCT01732822 .).

Effects of Policosanol and Ticlopidine in Patients with Intermittent Claudication: A Double-Blinded Pilot Comparative Study

Policosanol is a cholesterol-lowering drug with concomitant antiplatelet effects. The present study was undertaken to compare the effects of policosanol and ticlopidine in patients with moderately severe intermittent claudication (IC). The study had a 4-week baseline step, followed by a 20-week double-blinded, randomized treatment period. Twenty-eight eligible patients were randomized to policosanol 10 mg or ticlopidine 250 mg tablets twice daily (bid). Walking distances in a treadmill (constant speed 3.2 km/hr, slope 10°, temperature 25°C) were assessed before and after 20 weeks of treatment. Both groups were similar at baseline. Compared with baseline, policosanol significantly increased (p<0.01) mean values of initial (ICD) and absolute (ACD) claudication distances from 162.1 to 273.2 m and from 255.8 to 401.0 m, respectively. Ticlopidine also raised significantly (p<0.01) ICD (166.2 to 266.3 m) and ACD (252.9 to 386.4 m). Comparisons between groups did not show significant differences. Policosanol, but not ticlopidine, significantly (p<0.05), but modestly, increased the ankle/arm pressure ratio. After 10 weeks, policosanol significantly (p<0.001) lowered low-density lipoprotein-cholesterol (LDL-C), total cholesterol (TC) (p<0.01), and TC/HDL-C and raised (p<0.05) high-density lipoprotein-cholesterol (HDL-C). At study completion, policosanol lowered (p<0.001) LDL-C (30.2%), TC (16.9%), and TC/HDL-C (33.9%), increased (p<0.01) HDL-C (+31.7%), and left triglycerides unchanged. Ticlopidine did not affect the lipid profile variable. Policosanol induced modest, but significant, reductions (p<0.01) of fibrinogen levels compared with baseline and ticlopidine. Treatments were well tolerated and did not impair safety indicators. Three ticlopidine patients (21.4%) withdrew from the trial, only 1 owing to a serious adverse experience (AE) (unstable angina). Three other ticlopidine patients experienced mild AE (headache, diarrhea, and acidity). It is concluded that policosanol (10 mg bid) can be as effective as ticlopidine (250 mg bid) for improving walking distances of claudicant patients, and it could be advantageous for the global risk of these individuals owing to its cholesterol-lowering effects. This study is, however, just a pilot comparison, so that further studies in larger sample sizes are needed for definitive conclusions of the comparative effects of both drugs on patients with IC.

Effect of Cholesterol Lowering and Cardiovascular Risk Factors on the Progression of Aortoiliac Arteriosclerosis: A Quantitative Cineangiography Study

The post-Coronary Artery Bypass Graft (Post-CABG) trial has shown that aggressive compared to moderate lowering of low-density lipoprotein cholesterol (LDL-C) delayed the progression of obstructive disease in aortocoronary saphenous vein grafts and in the left main coronary artery. Patients had been allocated to high- and low-dose lovastatin therapy for a 4-5 year period. The present study evaluated the effect of LDL-C lowering and the role of cardiovascular risk factors on the progression of arteriosclerosis in the distal abdominal aorta and common iliac arteries. From one of the participating centers of the post-CABG trial, 145 patients who had adequate imaging of the aortoiliac arteries at baseline and follow-up were included. Angiographic outcomes, presumed to reflect progression of arteriosclerosis and obtained from lumen diameter (LD) measurements using quantitative cineangiography, were as follows: significant decrease of the minimum lumen diameter (LD) and increase of the maximum LD, percent lumen stenosis, and percent lumen dilatation. These outcomes were not significantly less frequent in patients randomly allocated to aggressive compared to moderate LDL-C lowering. Of 9 cardiovascular risk factors, only 2 were significantly related to progression of aortoiliac arteriosclerosis. Current smoking predicted both percent lumen stenosis increase and, to a lesser degree, percent lumen dilatation increase (p=0.010 and p=0.055, respectively). Abnormally high body mass index (BMI ≥25 kg/m2) correlated with percent lumen dilatation increase (p=0.006). Aggressive compared to moderate LDL-C lowering did not prevent or delay the progression of aortoiliac arteriosclerosis. Smoking predicted both lumen narrowing and dilatation presumably caused by arteriosclerosis. Abnormally high BMI, reflecting overweight or obesity, was strongly associated with vessel dilatation.

PGE1 and Other Prostaglandins in the Treatment of Intermittent Claudication: A Meta-analysis

In intermittent claudication, pharmacologic drugs and invasive measures are indicated in patients who do not benefit from exercise training. To evaluate the therapeutic role of prostaglandins (PGs), especially of prostaglandin E1 (PGE1), for this indication, the author performed a meta-analysis of all published prospective, randomized, controlled clinical studies in which descriptive sample statistics of the pain-free walking distance (PFWD) and the maximum walking distance (MWD) were available. In total, 9 studies with PGE1 and 4 studies with other PGs (beraprost, iloprost, AS-013) that met these selection criteria could be analyzed. In patients treated with PGE1 (n=344), PFWD increased significantly (p<0.001) more (+107%) than in patients treated with other PGs (n=402; +42%) or placebo (n=470; +24%). Similar results were also found for the MWD. Side effects were significantly (p<0.001) fewer with PGE1 therapy than with other PGs (14.0% vs 30.8% of patients). In conclusion, PGE1 proved to be the most effective and best tolerated of the PGs evaluated.

Quality of the assessment of primary and secondary endpoints in claudication and critical leg ischemia trials

Clinical trials in peripheral arterial disease (PAD) require an accurate definition of the disease for inclusion; they typically use treadmill testing, questionnaires and hemodynamic measures as primary and secondary endpoints. Trials of new pharmacologic therapies for PAD often employ multiple clinical sites with presumed expertise in the diagnosis and management of PAD as well as in clinical trials. However, considerable variability has been observed in the assessment of endpoints used in PAD trials, as well as a marked placebo response with treadmill testing. This variability and placebo response impact adversely on overall trial integrity, necessitate an inflated sample size, and may contribute to the large number of recently negative claudication trials. We hypothesized that site monitoring visits for evaluating testing methods would identify and characterize several critical issues that would contribute to poor testing quality. One hundred sites participating in three claudication trials for which peak walking time on the treadmill was the primary endpoint, and 16 sites participating in a critical leg ischemia study for which transcutaneous oxygen tension (TcPO2) was the primary endpoint were evaluated. Each site was visited one or more times by a clinical monitor trained in conducting a ‘site endpoint evaluation visit’ focusing on equipment, physical set-up of the room in which testing was to be conducted, and the site staff’s ability to conduct each of the specific measurements. Full reports were generated that covered a number of technical issues for each measurement and data were extracted from these reports to summarize the testing problems encountered at each site. Problems with treadmill testing were common. For example, 92% of sites had problems with their treadmill equipment, 58% did not perform proper treadmill familiarization, 24% did not start the treadmill test appropriately, 24% did not conduct the test properly, and 15% did not properly conclude the test to determine the peak walking time of the participant. Similar problems were encountered with the ankle-brachial index test, the administration of questionnaires and measurement of the TcPO2. Major deficiencies were identified at the majority of sites in the assessment of primary and secondary endpoints in PAD trials. These errors and improper testing provide a potential explanation for the wide variability and placebo responses observed in claudication and critical leg ischemia trials. Site interventions need to address these deficiencies in measurement to improve the quality of PAD trials.

Randomized trial of AT-1015 for treatment of intermittent claudication. A novel 5-hydroxytryptamine antagonist with no evidence of efficacy

AT-1015 is a novel selective 5-HT2A serotonin receptor antagonist that is known to impair platelet aggregation and vasoconstriction. Serotonin has been hypothesized to contribute to claudication symptoms in individuals with peripheral arterial disease (PAD) via micro-vascular vasoconstrictor and thrombotic effects. AT-1015 was thus evaluated in 439 patients with claudication who were randomized in a double-blind, placebo-controlled trial comparing 10 mg, 20mg, and 40 mg BID versus placebo for 24 weeks. Treadmill walking performance was assessed by peak walking time (PWT) and pain-free walking time (PFWT). Quality of life (QoL) was measured by the Walking Impairment Questionnaire (WIQ) and the Health Status Survey SF-36. Limb hemodynamics was assessed with the ankle-brachial index (ABI). The 40 mg arm was terminated prematurely by recommendation of the Data Safety Monitoring Committee due to an excess number of non-fatal myocardial infarctions. At study conclusion, there were no statistically significant differences in the mean change of PWT, PFWT, ABI and QoL between the 10 mg and 20 mg BID treatment groups compared with placebo. The proportion of patients who experienced an adverse event (AE) was similar across all treatment groups. Antimuscarinic and gastrointestinal AEs were more common in the AT-1015 treatment groups. Two deaths occurred: one in the placebo group and the other in the AT-1015 20 mg group. Although a prolongation of the QTc interval was observed in all groups, this was not clinically significant (QTc > 500ms). Mean supine pulse rates were significantly increased in all AT-1015 treatment groups, consistent with predicted antimuscarinic effects. Population pharmacokinetic analysis fit a one-compartment model with first-order absorption and elimination. These data indicate that selective serotonin receptor blockade does not improve exercise tolerance or quality of life in individuals with claudication.

Pain description in patients with isolated proximal (without distal) exercise-related lower limb arterial ischemia

Among the last 250 claudicants referred to the laboratory for transcutaneous oxygen pressure recording at exercise, we analyzed the symptoms reported by the 36 patients who showed isolated proximal (without distal) ischemia. Among the symptomatic proximal sites cited by these patients, the hip and thigh represent 60%, whereas the buttock is cited in fewer than 25% of cases. Buttock symptoms are reported in only 31% of symptomatic patients. ‘Buttock’ claudication is probably not the dominant symptom in isolated proximal vascular ischemia. Assessing proximal lower limb ischemia through the sole detection of ‘buttock pain’ could contribute to the underestimation of proximal vascular ischemia.

Masterclass series in peripheral arterial disease

Peripheral arterial disease (PAD) of the lower extremities is a common and potentially life-threatening manifestation of systemic atherosclerosis. Significant PAD is identified by an ankle brachial index (ABI) <0.90; its presence is strongly associated with the major modifiable cardiac risk factors. Early detection and treatment of asymptomatic PAD is a current focus of numerous cardiovascular guideline organizations as less than a third of patients report typical claudication symptoms. This has created an ever-increasing treatment gap, whereby millions of eligible patients are inadequately treated. Risk factor management including exercise, smoking cessation, and aggressive treatment of lipids and blood pressure are essential in PAD patients. However, life-long antiplatelet therapy provides additional reductions in vascular events beyond aggressive risk factor management. The use of aspirin as well as more potent antiplatelet therapies such as thienopyridines holds promise for reducing atherothrombosis in this very high-risk population.

Sarpogrelate, a 5-HT2A receptor antagonist in intermittent claudication. A Phase II European study

This was a multinational, multicentre, double-blind Phase II study in Europe to evaluate the efficacy and safety of two dose regimens (200 mg bid and 200 mg tid) of sarpogrelate (MCI-9042, 5-HT2A receptor antagonist) compared to placebo in patients with stable, moderately severe intermittent claudication. Following a single-blind placebo run-in period of 6 weeks, 364 (309 male and 55 female) patients (59.2 ± 8.4 years, mean SD) were randomized to receive sarpogrelate 200 mg bid, 200 mg tid or placebo for 24 weeks with a follow-up of 8 weeks. The primary objective was the increase of absolute claudication distance (ACD) at the end of treatment (week 24) compared to placebo. Analysis of covariance (ANCOVA) was performed on the log-transformed percentage of baseline ACD: loge (ACD/baseline). A responder analysis (defined as a 50% improvement in ACD) was also performed. There was a marked training/placebo effect on the ACD which persisted up to 16 weeks. At 24 weeks the primary objective did not reach statistical significance (200 mg bid vs placebo, p = 0.225; 200 mg tid vs placebo, p = 0.580). In the responder analysis, 200 mg bid showed a statistically significant difference vs placebo ( p = 0.035). In the exploratory analysis with completers (patients completing all treadmill tests), there was a statistical difference in ACD/baseline change for 200 mg bid ( p = 0.035) and in the responder analysis for 200 mg tid ( p = 0.044) at 24 weeks compared to placebo. Both treatments showed a carry-over effect for ACD during the 8-week follow-up (weeks 28-32). The treatment was well tolerated and no clinically significant safety concerns were reported. In conclusion, the study results confirm that sarpogrelate is well tolerated and although the primary endpoint failed to reach statistical significance, the responder analysis showed an increased absolute walking distance, which makes a further trial warranted, including a larger population, and possibly also a longer treatment period.

A pilot study of l-arginine supplementation on functional capacity in peripheral arterial disease

Peripheral arterial disease (PAD) impairs walking capacity and is often associated with a profound endothelial vasodilator dysfunction, characterized by reduced bioactivity and/or synthesis of endothelium-derived nitric oxide (NO). Previous studies have suggested that dietary supplementation of L-arginine, the precursor of NO, improves endothelium-dependent vasodilation, limb blood flow and walking distance. However, these studies have been small, and have used large intravenous doses of L-arginine. The optimal dose of L-arginine has not been determined. Accordingly, this pilot study was conducted to establish the lowest effective oral dose of L-arginine to improve walking distance in preparation for the definitive study. Patients with PAD and intermittent claudication ( n = 80) participated in this study. Eligibility criteria included: (1) ankle-brachial index (ABI) at rest ≤0.90; (2) post-exercise reduction in ABI ≥25%; and (3) difference in absolute claudication distance of ≤25% between two consecutive treadmill tests. Treadmill testing was performed using the Skinner-Gardner protocol and community-based walking was assessed using the walking impairment questionnaire. Patients were randomly assigned to oral doses of 0, 3, 6 or 9 g of L-arginine daily in three divided doses for 12 weeks. Treadmill testing was performed prior to administration of the study drug and again after 12 weeks of treatment. The study drug was well tolerated, with no significant adverse effects of L-arginine therapy. The safety laboratory studies were unremarkable, except for a statistically significant reduction in hematocrit in the L-arginine-treated groups. There was no significant difference observed in absolute claudication distance between the groups. However, a trend was observed for a greater increase in walking distance in the group treated with 3 g L-arginine daily, and there was a trend for an improvement in walking speed in patients treated with L-arginine. This pilot study provided data for safety, for power calculation and for dosing for the larger definitive trial that is now underway.

Design of the START-trial: STimulation of ARTeriogenesis using subcutaneous application of GM-CSF as a new treatment for peripheral vascular disease. A randomized, double-blind, placebo-controlled trial

Peripheral arterial disease (PAD) affects a large percentage of the elderly population. Standard invasive treatment, apart from risk factor modulation, consists of bypass surgery or percutaneous transluminal angioplasty. However, symptomatic recurrence rates are high for both procedures and a substantial part of the patient population with PAD is not a candidate for invasive revascularization due to complexity of the lesion and/or co-morbidity. Therapeutic arteriogenesis has been proposed as an alternative treatment option. The present paper describes the design of the START-trial. This trial aims to determine the potential of the proarteriogenic substance granulocyte/macrophage colony stimulating factor (GM-CSF) to increase maximal walking distance in patients with intermittent claudication. A double-blinded, randomized, placebo-controlled study will be performed in 40 patients with peripheral obstructive arterial disease Rutherford grade I, category 2 or 3, that are candidates for bypass surgery or percutaneous transluminal angioplasty. Based on pharmacokinetic and toxicologic studies, a dose of 10 mg/kg will be used. Patients will be treated for a period of 14 days on each consecutive day, with the last injection applied on day 12. The primary endpoint will be the change in walking distance from day 0 to day 14 as assessed by an exercise treadmill test. Secondary endpoints will be the ankle-brachial index at rest and after exercise, the pain-free walking distance and cutaneous microcirculatory alterations as assessed by laser Doppler fluxmetry. Iliac flow reserve and conductance will be measured by magnetic resonance imaging.

Medical Management of Intermittent Claudication

The symptoms of intermittent claudication (IC) lead sufferers to seek medical attention, potentially leading to substantial workup and invasive testing. However, only a minority of people with IC develop limb-threatening ischemia or symptoms of significant lifestyle-limiting claudication. Patients with IC have a substantial risk of concomitant cardiovascular and cerebrovascular disease. Assessment of co-morbidities and control of risk factors reduce the cardiovascular risk of these patients. A multitude of drugs have been developed and tested in numerous trials for the symptoms of IC. Although no drug alone offers a “cure” to IC, some are used as adjuvant therapy to reduce claudication symptoms.

Supervised exercise training combined with ginkgo biloba treatment for patients with peripheral arterial disease

Objectives: To evaluate whether a combination of supervised exercise training and ginkgo biloba treatment is a better treatment than exercise training alone for patients with peripheral arterial disease.

Design: A 24-week double-blind, placebo-controlled ginkgo biloba trial with the first 12-week period as a non-exercise control stage and the second 12-week period as an exercise training stage.

Setting: Exercise physiology laboratory.

Subjects: Twenty-two subjects with peripheral arterial disease.

Interventions: The subjects were randomly allocated into a ginkgo or a placebo group. During the first stage, the ginkgo group ingested standardized ginkgo biloba tablets with a daily dosage of 240 mg, while the placebo group received placebo tablets. During the second stage, all subjects engaged in a supervised treadmill-walking programme while continuing to take the same dosage of ginkgo biloba or placebo tablets.

Main measures: Walking capacity on treadmill, oxygen consumption during exercise, peripheral haemodynamics and blood viscosity were measured at baseline, and after the first and the second stages of treatment.

Results: The ginkgo group did not show significant changes in most of the measured variables after each stage of treatment, except that the maximal walking time was significantly increased after the combined treatment (from 236 ± 112 seconds to 557 ± 130 seconds, P < 0.001). However, similar response was also found in the placebo group after exercise training (from 384 ± 125 seconds to 820 ± 146 seconds, P < 0.001).

Conclusion: Supervised exercise training combined with ginkgo biloba treatment did not produce greater beneficial effects than exercise training alone in patients with peripheral arterial disease.

Limb hemodynamics are not predictive of functional capacity in patients with PAD

To the practicing clinician, it seems obvious that limb hemodynamics would be the primary determinant of walking distance. However, other determinants, such as skeletal muscle metabolism, may play a role. Accordingly, in the current study, we examined the relationship between measures of limb hemodynamics and walking capacity in patients with peripheral arterial disease (PAD). We measured toe and ankle pressures for calculation of toe-(TBI) and ankle (ABI)-brachial indices; basal and hyperemic calf blood flow (CBF; by plethysmography); and initial (ICT) and absolute (ACT) claudication time using the Skinner-Gardner protocol. As expected, PAD patients had impaired limb hemodynamics with reduced TBI, ABI and a reduction in ABI post-exercise. However, there was no relationship between any of the hemodynamic variables (including ABI, ABI reduction post-exercise, TBI, baseline or maximal CBF) and walking distance as assessed by ICT or ACT. A subset of PAD patients with an ACT >750 s (n =16; ‘long claudicators’) were compared with a subset of PAD patients with an ACT <260 s (n = 16; ‘short claudicators’). The average ACT in the long claudicants was over fivefold greater than the short claudicators. Surprisingly, there were no differences between the two groups in any of the hemo-dynamic variables. There was also no relationship between the initial ABI, TBI, toe pressure, baseline or hyperemic CBF, and the improvement in ACT over the 3-month course of the study. This study found little relationship between hemodynamic variables and functional capacity in PAD. Accordingly, to assess the response to therapeutic interventions, exercise performance and functional status need to be directly measured, and cannot be predicted from hemodynamic measurements.

Urokinase Thrombolysis in Acute-on-Chronic Vascular Occlusion of Lower Limb

Between January 2000 and June 2003, 70 patients (63 men and 7 women) with acute-on-chronic lower limb vascular occlusion underwent thrombolysis with 1 million units of urokinase. Forty-eight patients had unilateral and 22 had bilateral involvement; 9 had gangrenous changes. The mean age was 47 ± 9 years, 73% were smokers, and 13% had diabetes. The definition of a good response was either return of distal pulses or a warm limb and relief of pain at rest. Fifty-three (76%) patients (including 5 with gangrenous changes) had symptomatic improvement with thrombolysis (group 1), and 17 (24%) did not respond (group 2). All 70 patients (including 7 who later required amputation) underwent surgical intervention with a polytetrafluoroethylene interposition graft or arterioplasty. A good response to surgical treatment was found in significantly more patients (49/53, 92%) in group 1 compared to group 2 (7/17, 41%). Claudication distance after 6 months of follow-up improved in a significantly higher percentage of patients in group 1 (85%) than group 2 (38%). Preoperative thrombolysis improved the outcome and predicted the result of arterial surgery.

Nonoperative Management of Lower Extremity Claudication Caused by a Baker's Cyst: Case Report and Review of the Literature

A Baker's or popliteal cyst is a synovial cyst in the popliteal fossa arising from the knee joint. The majority of patients develop a popliteal mass that is asymptomatic, but in a small percentage of patients, complications and symptoms occur; these may not only encompass the popliteal veins and arteries but may also include cyst leakage, infection, hemorrhage, and compartment syndrome. Severe lower limb ischemia caused by a Baker's cyst is extremely rare, having been reported only six times since 1960; all patients were treated with surgical intervention.

We report the case of a 29-year-old male presenting with right calf claudication caused by a Baker's cyst. The patient was managed nonoperatively with nonsteroidal anti-inflammatory agents, proper exercises, and close observation. His claudication improved progressively and had completely disappeared at 12 months of follow-up. A repeat duplex arterial study showed that increased blood flow to the right foot and the right ankle/brachial index improved to 0.97 from 0.67. Repeat ultrasonography demonstrated that the size of the cyst decreased from 4.5 × 1.5 cm to 2.8 × 0.9 cm. The patient had been followed for 20 months and remained asymptomatic in the last 8 months. We will continue to follow the patient to evaluate the long-term outcome.

In summary, our own data and literature review suggest that the limb ischemia caused by Baker's cyst may be a transient condition and can be managed nonoperatively in selected patients.

Comparison of the Results of Percutaneous Transluminal Angioplasty and Stenting with Medical Treatment for Claudicants Who Have Superficial Femoral Artery Occlusive Disease

The outcomes of medical management of peripheral vascular disease localized to the superficial femoral artery (SFA) were compared with those obtained by percutaneous transluminal angioplasty (PTA) with or without stenting in a review of selected studies.

The natural history of localized SFA disease is favorable, with major amputation rates less than 10% and revascularization in only 18% of patients over a 10-year interval.

Conservative treatment of claudicants shows increases (150%) in walking distance if the ankle brachial index (ABI) is over 0.6 and patients stop smoking. Analysis of 10 trials (882 patients) of PTA with or without stenting found that the overall primary patency rates at 12 months were 71.1% for PTA plus stenting and 58.3% for PTA alone. Technical success with PTA with or without stenting is over 90%, and early results at 6 months are superior to those with exercise. In three randomized controlled trials, however, the difference between PTA and medical treatment at 2 years, whether measured by walking distance or ABI, was not significant, nor was the quality of life. For long-term improvement in walking distance (> 1 year) in the claudicant, intervention is not superior to medical treatment and a monitored exercise program. Consideration should be given to including a nonintervention control group and 2-year outcomes in the evaluation of new SFA stents.

Statins And Biomarkers In Claudicants With Peripheral Arterial Disease: Cross-sectional Study

This exploratory substudy of The Iron (Fe) and Atherosclerosis Study (FeAST) compared baseline inflammatory markers, including cytokines, C-reactive protein (CRP), and ferritin, in subjects with peripheral arterial disease (PAD) taking statins with subjects with PAD who were not taking statins. Inflammatory markers in the serum of 47 subjects with PAD not taking statins and a healthy cohort of 21 medication-free men were compared with 53 PAD subjects taking statins at entry to the FeAST.

Healthy subjects demonstrated lower levels of tumor necrosis factor (TNF)-R1, interleukin-6 (IL-6), and CRP. TNF-α R1 averaged 2.28 ng/mL versus 3.52 ng/mL, p  =  .0025; IL-6 averaged 4.24 pg/mL versus16.61 pg/mL, p  =  .0008; and CRP averaged 0.58 mg/dL versus 0.92 mg/dL, p  =  .0192. A higher level of IL-6 was observed in PAD statin takers versus PAD subjects not taking statins: 19.47 pg/mL versus 13.24 pg/mL, p  =  .0455. As expected, total cholesterol and low-density lipoprotein levels were lower in the statin-treated group, p  =  .0006 and p  =  .0001, respectively. No significant differences in inflammatory cytokines were detected for varying doses of simvastatin. Additionally, no significant differences in inflammatory biomedical markers were found in subjects with PAD alone compared with those with concomitant coronary artery disease (CAD).

Unexpectedly, serum inflammatory cytokine IL-6 levels were significantly higher in PAD subjects receiving statins. There was no difference in measured inflammatory markers in PAD subjects with concomitant CAD.

Padma 28 for intermittent claudication

BACKGROUND

Intermittent claudication (IC) is pain caused by chronic occlusive arterial disease that develops in a limb during exercise and is relieved with rest. Most drug treatments of IC have a limited effect in improving walking distance. Padma 28, a Tibetan herbal preparation, has been used to treat IC, but there is debate as to whether Padma 28 produces a clinical benefit beyond the placebo effect. This is an update of a review first published in 2013.

OBJECTIVES

To determine whether Padma 28 is effective, compared with placebo or other medications, in increasing pain-free and maximum walking distance for patients with intermittent claudication.

SEARCH METHODS

For this update the Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (September 2015), the Cochrane Register of Studies ((CENTRAL) (2015, Issue 8)) and clinical trials databases.

SELECTION CRITERIA

Randomised controlled trials of Padma 28 compared with placebo or other pharmacological treatments in people suffering from IC.

DATA COLLECTION AND ANALYSIS

All review authors independently assessed the selected studies and extracted the data. Risk of bias was evaluated independently by two review authors. Depending on the data provided in the individual trials, we extracted mean or median walking distance at the end of the trial, or change in walking distance over the course of the trial, or both. Where not provided, and whenever possible, the statistical significance of differences in these parameters between treatment and placebo groups in individual trials was calculated. Where possible, data were combined by meta-analysis.

MAIN RESULTS

No new trials were identified in the search for this review update. In total five trials involving 365 participants were included in this review. All trials compared Padma 28 with placebo for at least 16 weeks of follow-up. Pain-free and maximum walking distances both increased significantly in the groups treated with Padma 28, with no significant change in the placebo group. In general, the studies presented results comparing the treatment arms before and after treatment but made no comparisons between the Padma 28 and placebo groups. Pooled data of maximum walking distance after treatment with Padma 28 and placebo from two studies (193 participants) indicated a higher maximum walking distance (mean difference (MD) 95.97 m, 95% confidence interval (CI) 79.07 m to 112.88 m, P < 0.00001, very low quality evidence) in the Padma 28 group compared with placebo. The clinical importance of these observed changes in walking distance is unclear as no quality of life data were reported. There was no effect on ankle brachial index (ABI): change in ABI values between baseline and six months follow up MD -0.01, 95% CI -0.07 to 0.05, 1 study, 56 participants, P = 0.72, very low quality evidence). Mild side effects, especially gastrointestinal discomfort, tiredness and skin eruption, were reported but this outcome was not different between the Padma 28 and placebo groups (odds ratio 1.09, 95% CI 0.42 to 2.83, four studies, 231 participants, P = 0.86, very low quality evidence).

AUTHORS' CONCLUSIONS

Some evidence exists from individual trials to suggest that Padma 28 may be effective in increasing walking distances, at least in the short term (four months), in people with IC. Side effects do not appear to be a problem. However, the longer term effects of treatment are unknown and the clinical significance of the improvements in walking distance are questionable. Moreover, the quality of the evidence is limited by the small sample size of the available trials, limited reporting of statistical analyses that compared treatment groups, and relatively high withdrawal rates that were linked to the outcome. That is, patients were withdrawn if they failed to improve walking distance. There was also evidence of publication bias. We therefore feel there is currently insufficient evidence to draw conclusions regards the effectiveness of Padma 28 in the routine management of IC. Further well-designed research would be required to determine the true effects of this herbal preparation.

Trimetazidine hydrochloride as a new treatment for patients with peripheral vascular disease--an exploratory trial

OBJECTIVE

To evaluate the therapeutic effect of trimetazidine hydrochloride in peripheral vascular disease patients who had Rutherford classification grade 2-3.

PATIENTS AND METHODS

72 patients with Rutherford classification grade 2-3 in peripheral vascular were recruited successfully, they were randomly assigned to control group (35 cases) and trimetazidine group (37 cases), patients in control group received conventional treatment and trimetazidine group received conventional treatment plus trimetazidine hydrochloride for 6 months. Their ankle brachial index (ABI), maximum walking distance, pain onset time and the maximum walking time were compared before and after the treatment.

RESULTS

After 6 months' treatment, the ABI, maximum walking distance, pain onset time and the maximum walking time in two groups were both improved of when compared with before treatment (p < 0.05). The maximum walking distance, pain onset time and the maximum walking time in trimetazidine group were improved better than control (p < 0.05) while no evident improvement in ABI between the 2 groups (p > 0.05).

CONCLUSIONS

Conventional therapy plus trimetazidine hydrochloride could significantly improve the clinical symptoms of patients with Rutherford classification Grade 2-3 in peripheral vascular.

Pentoxifylline for intermittent claudication

BACKGROUND

Intermittent claudication (IC) is a symptom of peripheral arterial disease (PAD) and is associated with high morbidity and mortality. Pentoxifylline, one of many drugs used to treat IC, acts by decreasing blood viscosity, improving erythrocyte flexibility and promoting microcirculatory flow and tissue oxygen concentration. Many studies have evaluated the efficacy of pentoxifylline in treating individuals with PAD, but results of these studies are variable. This is an update of a review first published in 2012.

OBJECTIVES

To determine the efficacy of pentoxifylline in improving the walking capacity (i.e. pain-free walking distance and total (absolute, maximum) walking distance) of individuals with stable intermittent claudication, Fontaine stage II.

SEARCH METHODS

For this update, the Cochrane Vascular Group Trials Search Co-ordinator searched the Specialised Register (last searched April 2015) and the Cochrane Register of Studies (2015, Issue 3).

SELECTION CRITERIA

All double-blind, randomised controlled trials (RCTs) comparing pentoxifylline versus placebo or any other pharmacological intervention in patients with IC Fontaine stage II.

DATA COLLECTION AND ANALYSIS

Two review authors separately assessed included studies,. matched data and resolved disagreements by discussion. Review authors assessed the methodological quality of studies by using the Cochrane 'Risk of bias' tool and collected results related to pain-free walking distance (PFWD) and total walking distance (TWD). Comparison of studies was based on duration and dose of pentoxifylline.

MAIN RESULTS

We included in this review 24 studies with 3377 participants. Seventeen studies compared pentoxifylline versus placebo. In the seven remaining studies, pentoxifylline was compared with flunarizine (one study), aspirin (one study), Gingko biloba extract (one study), nylidrin hydrochloride (one study), prostaglandin E1 (two studies) and buflomedil and nifedipine (one study). The quality of the evidence was generally low, with large variability in reported findings.. Most included studies did not report on random sequence generation and allocation concealment, did not provide adequate information to allow selective reporting to be judged and did not report blinding of assessors. Heterogeneity between included studies was considerable with regards to multiple variables, including duration of treatment, dose of pentoxifylline, baseline walking distance and participant characteristics; therefore, pooled analysis was not possible.Of 17 studies comparing pentoxifylline with placebo, 14 reported TWD and 11 reported PFWD; the difference in percentage improvement in TWD for pentoxifylline over placebo ranged from 1.2% to 155.9%, and in PFWD from -33.8% to 73.9%. Testing the statistical significance of these results generally was not possible because data were insufficient. Most included studies suggested improvement in PFWD and TWD for pentoxifylline over placebo and other treatments, but the statistical and clinical significance of findings from individual trials is unclear. Pentoxifylline generally was well tolerated; the most commonly reported side effects consisted of gastrointestinal symptoms such as nausea.

AUTHORS' CONCLUSIONS

Given the generally poor quality of published studies and the large degree of heterogeneity evident in interventions and in results, the overall benefit of pentoxifylline for patients with Fontaine class II intermittent claudication remains uncertain. Pentoxifylline was shown to be generally well tolerated.Based on total available evidence, high-quality data are currently insufficient to reveal the benefits of pentoxifylline for intermittent claudication.

Cilostazol for intermittent claudication

BACKGROUND

Peripheral arterial disease (PAD) affects between 4% and 12% of people aged 55 to 70 years, and 20% of people over 70 years. A common complaint is intermittent claudication, characterised by pain in the legs or buttocks that occurs with exercise and which subsides with rest. Compared with age-matched controls, people with intermittent claudication have a three- to six-fold increase in cardiovascular mortality. Symptoms of intermittent claudication, walking distance, and quality of life can be improved by risk factor modification, smoking cessation, and a structured exercise programme. Antiplatelet treatment is beneficial in patients with intermittent claudication for the reduction of vascular events but has not previously been shown to influence claudication distance. This is an update of a review first published in 2007.

OBJECTIVES

To determine the effect of cilostazol (an antiplatelet treatment) on improving initial and absolute claudication distances, and in reducing mortality and vascular events in patients with stable intermittent claudication.

SEARCH METHODS

For this update, the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched October 2013) and CENTRAL (2013, Issue 9).

SELECTION CRITERIA

Double-blind, randomised controlled trials (RCTs) of cilostazol versus placebo, or versus other antiplatelet agents in patients with stable intermittent claudication.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for selection and independently extracted data. Disagreements were resolved by discussion. We performed the meta-analysis as a fixed-effect model with weighted mean differences (WMDs) and 95% confidence intervals (CIs) for continuous data, and odds ratios (ORs) with 95% CIs for dichotomous data.

MAIN RESULTS

We included fifteen double-blind, RCTs comparing cilostazol with placebo, or medications currently known to increase walking distance e.g. pentoxifylline. There were a total of 3718 randomised participants with treatment durations ranging from six to 26 weeks. All participants had intermittent claudication secondary to PAD. Comparisons included cilostazol twice daily, with dosages of 50 mg, 100 mg and 150 mg compared with placebo, and cilostazol 100 mg, twice daily, compared with pentoxifylline 400 mg, three times daily. The methodological quality of the trials was generally low, with the majority being at an unclear risk for selection bias, performance bias, detection bias and other bias. Attrition bias was generally low, but reporting bias was high or unclear in the majority of the studies. For eight studies data were compatible for comparison by meta-analysis, but data for seven studies were too heterogenous to be pooled. For the studies included in the meta-analysis, for initial claudication distance (ICD - the distance walked on a treadmill before the onset of calf pain) there was an improvement in the cilostazol group for the 100 mg and 50 mg twice daily, compared with placebo (WMD 31.41 metres, 95% CI 22.38 to 40.45 metres; P < 0.00001) and WMD 19.89 metres, 95% CI 9.44 to 30.34 metres; P = 0.0002), respectively. ICD was improved in the cilostazol group for the comparison of cilostazol 150 mg versus placebo and cilostazol 100 mg versus pentoxifylline, but only single studies were used for these analyses. Absolute claudication distance (ACD - the maximum distance walked on a treadmill) was significantly increased in participants taking cilostazol 100 mg and 50 mg twice daily, compared with placebo (WMD 43.12 metres, 95% CI 18.28 to 67.96 metres; P = 0.0007) and WMD 32.00 metres, 95% CI 14.17 to 49.83 metres; P = 0.0004), respectively. As with ICD, ACD was increased in participants taking cilostazol 150 mg versus placebo, but with only one study an association cannot be clearly determined. Two studies comparing cilostazol to pentoxifylline had opposing findings, resulting in an imprecise CI (WMD 13.42 metres (95% CI -43.51 to 70.35 metres; P = 0.64). Ankle brachial index (ABI) was lowered in the cilostazol 100 mg group compared with placebo (WMD 0.06, 95% CI 0.04 to 0.08; P < 0.00001). The single study evaluating ABI for the comparison of cilostazol versus pentoxifylline found no change in ABI.There was no association between treatment type and all-cause mortality for any of the treatment comparisons, but there were very few events, and therefore larger, adequately powered studies will be needed to assess if there is a relationship. Only one study evaluated individual cardiovascular events, and from this study there is no clear evidence of a difference between any of the treatment groups and risk of myocardial infarction or stroke. We evaluated adverse side effects, and in general cilostazol was associated with a higher odds of headache, diarrhoea, abnormal stool, dizziness and palpitations. We only reported quality of life measures descriptively as there was insufficient statistical detail within the studies to combine the results, although there was a possible indication in improvement of quality of life in the cilostazol treatment groups.

AUTHORS' CONCLUSIONS

Cilostazol has been shown to be of benefit in improving walking distance in people with intermittent claudication secondary to PAD. Although there is an increase in adverse side effects, they are generally mild and treatable. There is currently insufficient data on whether taking cilostazol results in a reduction of all-cause mortality and cardiovascular events or an improvement in quality of life. Future research into the effect of cilostazol on intermittent claudication should carefully consider comparability, sample size and homogeneity when designing a study.

Efficacy of clopidogrel treatment and platelet responsiveness in peripheral arterial procedures

INTRODUCTION

Long-term antiplatelet therapy with clopidogrel has been recommended in patients undergoing peripheral arterial procedures. Poor antiplatelet effect of clopidogrel or high on-clopidogrel platelet reactivity (HCPR) has been recently identified in patients with peripheral arterial disease (PAD).

AREAS COVERED

This review focuses on the use of clopidogrel and the phenomenon of HCPR in PAD patients treated for intermittent claudication or critical limb ischaemia (CLI). The authors summarize current guidelines and recommendations for use of clopidogrel following peripheral arterial procedures and explore the prevalence and clinical impact of HCPR in the PAD population. Underlying mechanisms of HCPR and relevant clinical and genetic factors are analyzed with particular attention to the potential utility of point-of-care platelet function testing (PFT).

EXPERT OPINION

Clopidogrel is a safe, effective and well-tolerated antiplatelet agent in PAD patients following peripheral arterial revascularization. Dual-antiplatelet therapy could also be considered after complex endovascular procedures. HCPR has been identified in more than 50% of PAD patients on clopidogrel and has been related with significantly increased re-intervention rates. Incidence of HCPR is significantly higher in patients with CLI, diabetes mellitus and chronic renal disease. Personalized antiplatelet therapy on the basis of PFT is an elegant emerging concept for optimization of platelet inhibition and potential identification of patients at increased risk of bleeding and warrants investigation in future large-scale trials.

Anticoagulants (heparin, low molecular weight heparin and oral anticoagulants) for intermittent claudication

BACKGROUND

Anticoagulant treatment for intermittent claudication might improve functional capacity and prevent acute cardiovascular complications caused by peripheral obstructive arterial disease. This is an update of the review first published in 2001.

OBJECTIVES

To assess the effects of anticoagulant drugs (heparin, low molecular weight heparin (LMWH) and oral anticoagulants) in patients with intermittent claudication (Fontaine stage II) in terms of improving walking capacity (pain-free walking distance or absolute walking distance), mortality, cardiovascular events, ankle/brachial pressure index, progression to surgery, amputation-free survival and side effects of these drugs.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 2013) and CENTRAL (2013, Issue 4).

SELECTION CRITERIA

All randomised trials of anticoagulants used to treat patients with intermittent claudication.

DATA COLLECTION AND ANALYSIS

Seven studies were included. Only three studies (two evaluating oral anticoagulants, one evaluating heparin) met the high quality methodological inclusion criteria and were included in the primary analysis. Four other studies were included in the sensitivity analysis. The authors extracted the data independently.

MAIN RESULTS

No new studies were included for this update. Seven studies with a combined total of 802 participants were included in this review. No significant difference was observed between heparin treatment and control groups for pain-free walking distance or maximum walking distance at the end of treatment. There were no data to indicate that LMWHs benefit walking distance. Revascularisation or amputation-free survival rates were reported in one study only with a five year follow-up. No study reported a significant effect on overall mortality or cardiovascular events and the pooled odds ratios were not significant for these outcomes either. Major and minor bleeding events were significantly more frequent in the group treated with oral anticoagulants compared to control, with a non-significant increase in fatal bleeding events. No major bleeding events were reported in the study evaluating heparin, while a non-significant increase in minor bleeding events was reported.

AUTHORS' CONCLUSIONS

The benefit of heparin, LMWHs and oral anticoagulants for treatment of intermittent claudication has not been established while an increased risk of major bleeding events has been observed, especially with oral anticoagulants. There is no clear evidence to support the use of anticoagulants for intermittent claudication at this stage.

Cilostazol: improving walking distance in patients with intermittent claudication

Intermittent claudication is a common, disabling symptom of peripheral arterial disease that limits walking distance and is associated with an increased cardiovascular risk of acute limb- or life-threatening complications. Very few patients with intermittent claudication (<7%) are suitable candidates for surgical revascularization, yet in contrast to the treatment of stable angina, few effective medical therapies (apart from exercise) are available for the symptomatic relief of intermittent claudication. The phosphodiesterase-3 inhibitor, cilostazol (Pletal, Otsuka Pharmaceuticals Ltd), is the first symptom-relieving treatment for intermittent claudication that has been evaluated successfully in large multicenter placebo-controlled, double-blind clinical trials (involving >2000 patients). A meta-analysis of the eight major efficacy studies with cilostazol has shown significant improvements in pain-free and maximum walking distance, and a good overall safety and tolerability profile. Thus, in the UK, USA and Japan, cilostazol administered at 100 mg twice daily is licensed for symptom relief in patients with stable, moderate-to-severe intermittent claudication, as an adjunct to nonpharmacological approaches such as exercise.