Effect of verapamil in intermittent claudication A randomized, double-blind, placebo-controlled, cross-over study after individual dose-response assessment

Thromboangiitis obliterans: Aggressive angioplasty provides a potential solution (randomized pilot study)

Background

Thromboangiitis obliterans is an inflammatory disease affecting both medium- and small-sized vessels. Vasodilators, antiplatelets were proposed for treatment but the effect was minimal.

Objective

This study was conducted to investigate the effect of balloon angioplasty on patients with Buerger's disease compared to medical treatment.

Methods

Between January 2006 and December 2016, 82 patients with Buerger's disease were enrolled in the study, of whom 52 were randomized to the aggressive endovascular intervention and 30 were randomized medically by cilostazol and aspirin as a control group. In all, 23% of the patients presented with severe claudication, 50% with ischemic rest pain and 27% with ischemic ulcers. Randomization was done using the opaque envelope method. Allocation concealment was maintained to ensure no selection bias. Patient groups were compared for the duration of ulcer healing, ankle-brachial index, peak systolic velocity changes and transcutaneous oximetry (TcPO2) level for 30 months.

Results

No major procedural complications occurred in the endovascular group. Angiographic success was achieved in 100% of supragenicular lesions but in 90% of infrapopliteal lesions. The endovascular group showed a statistically significant improvement in the ulcer healing size and duration at 6 months after the procedure with a mean time of 3 ± 0.9 months compared to 5.8 ± 1.69 months for the medical treatment group (p < 0.001), the mean TcPO2 from 27.23 ± 16.75 mm Hg (range: 0-56 mm Hg) before the procedure to 71.32 ± 12.94 mm Hg (range: 52-92 mm Hg) following revascularization (p < 0.01). The mean ankle-brachial index significantly improved from 0.54 ± 0.14 preoperatively to 0.82 ± 0.08 at final follow-up (p < 0.01).

Conclusion

The endovascular therapy should be considered as an effective, safe, minimally invasive method in the light of the promising results after a modification of the standard technique.

The association of race with quality of health in peripheral artery disease following peripheral vascular intervention: The Q-PAD Study

Black patients have a higher prevalence of peripheral artery disease (PAD) than white patients, and also tend to have a greater extent and severity of disease, and poorer outcomes. The association of race with quality of health (QOH) after peripheral vascular intervention (PVI), however, is less well-known. In our study, we hypothesized that after PVI, black patients experience worse QOH than white patients. We retrospectively assessed racial differences in health status using responses to the Peripheral Arterial Questionnaire (PAQ) at baseline (pre-PVI) and up to 6 months following PVI among 387 patients. We used the PAQ summary score (which includes physical limitation, symptoms, social function and quality of life) as a measure of QOH. We compared QOH scores at baseline and at follow-up after PVI between black ( n=132, 34.1%) and white ( n=255, 65.9%) patients. We then computed the change in score from baseline to follow-up for each patient (the delta) and compared the median delta between the two groups. Multivariable regression was used to model the delta QOH after controlling for factors associated with race or with the delta QOH. There was no significant difference in mean QOH by race either at baseline ( p=0.09) or at follow-up ( p=0.45). There was no significant difference in the unadjusted median delta by race (white 25.3 vs black 21.5, p=0.28) and QOH scores improved significantly at follow-up in both groups, albeit the improvement was marginally lower in black compared with white patients after adjustment for baseline confounders ( b = -6.6, p=0.05, 95% CI -13.2, -0.11).

Pathogenesis of thromboangiitis obliterans: Gene polymorphism and immunoregulation of human vascular endothelial cells

Thromboangiitis obliterans (TAO) is a nonatherosclerotic, segmental, inflammatory vasculitis, which commonly affects the small- and medium-sized arteries of the upper and lower extremities. Despite its discovery more than a century ago, little progress has been made in its treatment. Unless the pathogenesis is elucidated, therapeutic approaches will be limited. The purpose of this review article is to collate current knowledge of mechanisms for the pathogenesis of thromboangiitis obliterans and to propose potential mechanisms from a genetic and immunoreactive point of view for its inception. Therefore, we discuss the possibility that the pathogenesis of this disease is due to a type of gene polymorphism, which leads to an immunological inflammatory vasculitis associated with tobacco abuse, highly linked to T cells, human vascular endothelial cells (HVECs), and the TLR-MyD88-NFκB pathway, distinct from arteriosclerosis obliterans and other vasculitides.

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.

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.

Thromboangiitis Obliterans (Buerger's Disease)-Current Practices

Thromboangiitis obliterans (TAO) is a nonatherosclerotic, segmental inflammatory disease that most commonly affects the small and medium-sized arteries and veins in the upper and lower extremities. Cigarette smoking has been implicated as the main etiology of the disease. In eastern parts of the world TAO forms 40-60% of peripheral vascular diseases. Clinical features and angiographic finding are the basis of early diagnosis of TAO. Abstinence from smoking is the only definitive treatment to prevent disease progression. Medical management in form of aspirin, pentoxyfylline, cilostazol, and verapamil increase pain-free walking distance in intermittent claudication, but long term usage fails to prevent disease progression in patients who continue to smoke. Surgical treatment in form of revascularization, lumbar sympathectomy, omentopexy, and Ilizarov techniques help reduce pain and promote healing of trophic changes. Newer treatment modalities like spinal cord stimulation, prostacyclin, bosentan, VEGF, and stem cell therapy have shown promising results. Latest treatment options include peripheral mononuclear stem cell, and adipose tissue derived mononuclear stem cells have been shown to be effective in preventing disease progression, decrease major amputation rates, and improving quality of life.

Treatment strategies for peripheral artery disease

Peripheral arterial disease is an underecognized manifestation of systemic atherosclerosis associated with high rates of cardiovascular morbidity and mortality. The rationale of therapy is to reduce cardiovascular risk, improve symptoms of intermittent claudication, and prevent the development of critical limb ischemia and amputation. Exercise therapy and several pharmacologic agents have been shown to improve walking distance in patients with intermittent claudication. Patients with lifestyle-interfering symptoms despite exercise, or those who progress to critical limb ischemia, frequently undergo revascularization. Endovascular techniques are commonly used in these patients. Combined pharmacological and endovascular strategies will play an increasing role in management of these patients in the future.

A method for evaluating drug effects on intermittent claudication using a treadmill in rats with unilateral hindlimb artery occlusion

INTRODUCTION

We have developed an in vivo experimental model for evaluating peripheral arterial insufficiency and predicting the efficacy of drugs on intermittent claudication (IC). We found that rats that had been running normally on a treadmill developed a gait disturbance when a hindlimb artery was unilaterally occluded. We hypothesized that the distance run before gait disturbance developed (DGD) in rats with occlusion of a hindlimb artery might be an appropriate index of the severity of peripheral insufficiency, and that the model might serve as a test bed for evaluating drug efficacy. To prove this hypothesis, we examined whether DGD was determined by severity of hindlimb ischemia. Furthermore, we also examined whether cilostazol, which has been proved to have ameliorative effects in patients with IC, increased DGD.

METHODS

To vary the severity of ischemia, either the superficial femoral artery, the distal portion of the iliac artery, or the proximal portion of iliac artery was unilaterally occluded. After a recovery period, these rats were subjected to a treadmill test (15 m/min and 15% incline) to determine DGD and examine the effect of cilostazol on DGD.

RESULTS

DGD was the longest and shortest in rats with superficial femoral artery and proximal portion of iliac artery occlusion, respectively. Intermediate DGD was observed in rats with distal portion of iliac artery occlusion. These data suggest that DGD is correlated with the severity of hindlimb ischemia. Two weeks or longer administration of cilostazol 30 and 100 mg/kg twice a day evoked a significant increase in DGD.

DISCUSSION

Peripheral arterial insufficiency and its modulation by drugs can be evaluated in rats with unilateral hindlimb artery occlusion, on a treadmill, by measuring DGD.

Pharmacologic treatment for intermittent claudication

In contradistinction to chronic critical limb ischemia, the peripheral arterial disease patient with intermittent claudication is at relatively low risk for limb loss. As a result, initial claudication management should employ non-interventional therapies rather than immediate catheter-based or surgical revascularization. Although exercise therapy is the most efficacious conservative treatment for claudication, supervised exercise programs are not widely available at present. Consequently, a pharmacologic agent can be utilized to lessen the symptoms and improve the function of the claudicant. This manuscript provides a comprehensive review of the various pharmacotherapies that have been investigated for improving walking distance in the setting of intermittent claudication. Cilostazol, a phosphodiesterase III inhibitor, appears to provide the greatest benefit, significantly improving not only walking distance but quality of life as well. Early trials indicate that propionyl-L-carnitine, oral prostaglandins, L-arginine, and therapeutic angiogenesis may eventually yield significant benefit in lessening the symptoms of intermittent claudication.

Pharmacotherapy for peripheral arterial disease: emerging therapeutic options

Although endovascular therapy has revolutionized the management of patients with peripheral arterial disease (PAD), noninterventional regimens, such as structured exercise therapy, atherosclerotic risk factor modification, and pharmacotherapy, are effective in patients suffering from mild-to-moderate PAD and intermittent claudication (IC). For more than a decade, the only pharmacologic therapy for IC available in the United States was pentoxifylline, which had demonstrated superiority in improving walking distances but offered minimal clinical benefit. Recently, basic research into the pathophysiology of IC has led to the development of cilostazol, a new pharmacologic agent approved for treatment of this condition in 1999. Ongoing research in the use of angiogenic growth factors has further broadened the range of potential alternatives to treatment in patients with PAD. Revascularization procedures, including nonsurgical and surgical techniques, can thus be reserved to improve patency and reduce the risk of limb loss in patients with PAD and IC with more severe impairment.

Comparison of the long-term results between surgical and conservative treatment in patients with intermittent claudication

BACKGROUND

The optional therapeutic strategy for patients with intermittent claudication remains controversial. In this study, we investigated the influence of surgical and conservative therapies on improving the quality of life in patients with intermittent claudication.

METHODS

We analyzed 427 patients who were admitted to our hospital with intermittent claudication in their legs during a 15-year period from January 1984 to December 1999. We separated them into 2 groups; 259 patients (362 legs) were treated surgically and 168 patients were treated conservatively.

RESULTS

At the suprainguinal and infrainguinal (above knee) region, the surgery group showed significantly better rate of improvement than did the conservative group, but in the infrainguinal (below knee) region, there was no significant difference between the 2 groups. The 3-year and 5-year patency rates for the arterial reconstruction of the suprainguinal and infrainguinal region was satisfactory, but that of the infrainguinal region was not very good even if an auto vein graft was used.

CONCLUSIONS

Aggressive surgical treatment is therefore recommended in patients whose distal anastomotic region is above the knee, because there are great benefits from surgical reconstruction. However, in patients whose distal anastomotic region is below the knee, conservative treatment might be just as effective as surgery.

Peripheral vascular disease and hypertension: a forgotten association?

Peripheral vascular disease (PVD) is associated with a high cardiovascular morbidity and mortality. Intermittent claudication is the most common symptomatic manifestation of PVD, but is also an important predictor of cardiovascular death, increasing it by three-fold, and increasing all-cause mortality by two to five-fold. Hypertension is a common and important risk factor for vascular disorders, including PVD. Of hypertensives at presentation, about 2-5% have intermittent claudication, with this prevalence increasing with age. Similarly, 35-55% of patients with PVD at presentation also have hypertension. Patients who suffer from hypertension with PVD have a greatly increased risk of myocardial infarction and stroke. Apart from the epidemiological associations, hypertension contributes to the pathogenesis of atherosclerosis, the basic underlying pathological process underlying PVD. Hypertension, in common with PVD, is associated with abnormalities of haemostasis and lipids, leading to an increased atherothrombotic state. Nevertheless, none of the large antihypertensive treatment trials have adequately addressed whether a reduction in blood pressure causes a decrease in PVD incidence. There is therefore an obvious need for such outcome studies, especially since the two conditions are commonly encountered together.

Nutritional therapy for peripheral arterial disease: a double-blind, placebo-controlled, randomized trial of HeartBar

We investigated the clinical effects of a food bar enriched with L-arginine and a combination of other nutrients known to enhance the activity of endothelium-derived nitric oxide (EDNO) in individuals with claudication from atherosclerotic peripheral arterial disease. The study was a 2-week, double-blind, placebo-controlled trial of subjects randomized to three groups (two active bars, one active and one placebo bar, and two placebo bars per day) followed by an 8-week open-label period. Subjects (n=41) were outpatient volunteers with intermittent claudication. Pain-free and total walking distances were measured by variable-grade, treadmill exercise testing. Quality of life was assessed using the Medical Outcome Survey (SF-36). After 2 weeks of treatment, the pain-free walking distance increased 66% while the total walking distance increased 23% in the group taking two active bars/day. The general and emotional/social functioning components of the SF-36 also improved. These effects were not observed in the one active bar/day and placebo groups. The effects were maintained after 10 weeks and, in addition, an improvement in walking distance was observed in the group taking one active bar. These findings reveal that use of a nutrient bar designed to enhance EDNO activity improves pain-free and total walking distance as well as quality of life in individuals with intermittent claudication.

Current and future drug therapies for claudication

The primary objectives of claudication treatment are to reduce cardiovascular mortality and improve walking ability. Patients with claudication have 60% mortality over 10 years, with most deaths due to myocardial infarction and stroke. Aggressive risk-factor modification is required in all these patients, particularly smoking cessation, lipid modification, and treatment of hypertension, diabetes and elevated homocysteine levels. Aspirin, ticlopidine and clopidogrel are all effective in reducing the risk of myocardial infarction, stroke and vascular death, and thus antiplatelet therapy should be considered in all claudicants. Patients with disabling claudication should be considered for therapies that relieve claudication pain and improve exercise performance, the most effective being exercise training and smoking cessation. Pentoxifylline, the only approved claudication drug in the United States, has modest efficacy in improving treadmill exercise performance. Other drugs shown to be of some benefit in patients with claudication include propionyl-L-carnitine, cilostazol and possibly prostaglandin derivatives. Several antiplatelet agents and angiogenic growth factors are also being evaluated for the treatment of claudication.