Intermittent claudication and rest pain: physiologic concepts and therapeutic approaches

Effect of Supervised Exercise Program on Individuals in Peripheral Arterial Disease with Type 2 Diabetes Mellitus - A Systematic Review

BACKGROUND

Type 2 Diabetes Mellitus (T2DM) is usually accompanied by various micro and macro vascular complications. Peripheral Arterial Disease (PAD) is one of the major complications of diabetes which is accountable for morbidity and mortality throughout the world. The first line of treatment in these individuals is life style modification and exercise. There is a dearth of literature on effect of supervised exercise program in PAD with T2DM on quality of life, walking impairment, change in Ankle Brachial Index (ABI) values. So, we conducted a systematic review to explore the available literature on supervised exercise program in PAD with T2DM.

METHODS

We conducted a systematic review (PubMed, Web of Science, CINAHL and Cochrane) to summarise the evidence on a supervised exercise program in PAD with T2DM. Randomised and nonrandomised studies were included in the review.

RESULTS

Three studies met the inclusion criteria. The outcomes taken into accounts by the studies were the quality of life, walking impairment questionnaire, Ankle brachial index. Neither of the studies matched in their supervised exercise program nor in their outcome.

CONCLUSION

In conclusion, the data evaluating the supervised exercise program in PAD with T2DM is inadequate to determine its effect on this population. Future large-scale studies can be conducted on both subjective and objective outcomes of PAD with T2DM to have a better understanding of the condition and for a universally acceptable exercise program for these individuals which the healthcare practitioners can use in their practice. Prospero registration number: CRD42018112465.

Naftidrofuryl for intermittent claudication

BACKGROUND

Lifestyle changes and cardiovascular prevention measures are a primary treatment for intermittent claudication (IC). Symptomatic treatment with vasoactive agents (Anatomic Therapeutic Chemical Classification (ATC) for medicines from the World Health Organisation class CO4A) is controversial.

OBJECTIVES

To evaluate evidence on the efficacy and safety of oral naftidrofuryl (ATC CO4 21) versus placebo on the pain-free walking distance (PFWD) of people with IC by using a meta-analysis based on individual patient data (IPD).

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched October 2012) and CENTRAL (2012, Issue 9).For the original review the authors handsearched the European Journal of Vascular and Endovascular Surgery (1984 to 1994) and checked relevant bibliographies. They contacted the registration holder of naftidrofuryl and the authors of identified trials for any unpublished data.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) with low or moderate risk of bias for which the IPD were available.

DATA COLLECTION AND ANALYSIS

We collected data from the electronic data file or from the case report form and checked the data by a statistical quality control procedure. All randomized patients were analyzed following the intention-to-treat (ITT) principle. The geometric mean of the relative improvement in PFWD was calculated for both treatment groups in all identified studies.The effect of the drug was assessed compared with placebo on final walking distance (WDf) using multilevel and random-effect models and adjusting for baseline walking distance (WD0). For the responder analysis, therapeutic success was defined as an improvement of walking distance of at least 50%.

MAIN RESULTS

We included seven studies in the IPD (n = 1266 patients). One of these studies (n = 183) was only used in the sensitivity analysis so that the main analysis included 1083 patients. The ratio of the relative improvement in PFWD (naftidrofuryl compared with placebo) was 1.37 (95% confidence interval (CI) 1.27 to 1.49, P < 0.001). The absolute difference in responder rate, or proportion successfully treated, was 22.3% (95% CI 17.1% to 27.6%). The calculated number needed to treat was 4.5 (95% CI 3.6 to 5.8).

AUTHORS' CONCLUSIONS

Oral naftidrofuryl has a statistically significant and clinically meaningful, although moderate, effect of improving walking distance in the six months after initiation of therapy for people with intermittent claudication. Access by researchers to data from RCTs that are suitable for IPD analysis should be possible through repositories of data from pharmacological trials. Regular formal appraisal of the balance of risk and benefit is needed for older pharmaceutical products.

Naftidrofuryl for intermittent claudication

BACKGROUND

Lifestyle changes and cardiovascular prevention measures are a primary treatment for intermittent claudication (IC). Symptomatic treatment with vasoactive agents (Anatomic Therapeutic Chemical Classification (ATC) for medicines from the World Health Organisation class CO4A) is controversial.

OBJECTIVES

To evaluate evidence on the efficacy and safety of oral naftidrofuryl (ATC CO4 21) versus placebo on the pain-free walking distance (PFWD) of people with IC by using a meta-analysis based on individual patient data (IPD).

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Trials Register (last searched December 2007) and CENTRAL (last searched 2007, Issue 4). We searched MEDLINE, EMBASE, International Pharmaceutical Abstracts, the Science Citation Index and contacted the authors and checked the reference lists of retrieved articles. We asked the manufacturing company for IPD.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) with low or moderate risk of bias for which the IPD were available.

DATA COLLECTION AND ANALYSIS

We collected data from the electronic data file or from the case report form and checked the data by a statistical quality control procedure. All randomized patients were analyzed following the intention-to-treat (ITT) principle. The geometric mean of the relative improvement in PFWD was calculated for both treatment groups in all identified studies. The effect of the drug was assessed compared with placebo on final walking distance (WDf) using multilevel and random-effect models and adjusting for baseline walking distance (WD0). For the responder analysis, therapeutic success was defined as an improvement of walking distance of at least 50%.

MAIN RESULTS

We included seven studies in the IPD (n = 1266 patients). One of these studies (n = 183) was only used in the sensitivity analysis so that the main analysis included 1083 patients. The ratio of the relative improvement in PFWD (naftidrofuryl compared with placebo) was 1.37 (95% confidence interval (CI) 1.32 to 1.51, P < 0.001). The absolute difference in responder rate, or proportion successfully treated, was 22.3% (95% CI 17.1% to 27.6%). The calculated number needed to treat was 4.5 (95% CI 3.6 to 5.8).

AUTHORS' CONCLUSIONS

Naftidrofuryl has a statistically significant and clinically meaningful effect of improving walking distance in the six months after initiation of therapy for people with intermittent claudication. Access by researchers to data from RCTs that is suitable for IPD analysis should be possible through repositories of data from pharmacological trials. Regular formal appraisal of the balance of risk and benefit is needed for older pharmaceutical products.

Differential impairment of vasodilator responsiveness of peripheral resistance and conduit vessels in humans with atherosclerosis

The purpose of this study was to assess the effect of atherosclerosis on the regulation of limb blood flow. To examine this issue, the reactivity of resistance and conduit vessels was evaluated in 11 patients with peripheral atherosclerotic disease and six control subjects. Responsiveness of resistance vessels was measured by venous occlusion plethysmography. Responsiveness of conduit vessels was determined by quantitative angiography to measure the diameter of the superficial femoral artery. To distinguish endothelium-dependent vasodilation from that caused by direct smooth muscle relaxation, each participant received intra-arterial infusions of methacholine and nitroprusside, respectively. Flow-mediated dilation of the superficial femoral artery was determined during reactive hyperemia. Vasoconstrictor function was determined by the infusion of phenylephrine. Methacholine reduced calf vascular resistance in the control subjects but not in the patients with atherosclerosis (-64 +/- 11% versus 6 +/- 18%, p less than 0.01). Nitroprusside decreased calf vascular resistance comparably in each group (-51 +/- 5% versus -42 +/- 4%, p = NS). The vasoconstrictor effect of phenylephrine was similar in each group (105 +/- 30% versus 108 +/- 22%, p = NS). In the superficial femoral artery, the vasodilator responses to both methacholine (20 +/- 4% versus 1 +/- 4%, p less than 0.05) and nitroprusside (19 +/- 4% versus 5 +/- 4%, p less than 0.05) were blunted in the atherosclerotic patients as was the vasoconstrictive response to phenylephrine (-15 +/- 1% versus -1 +/- 5%, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Radiating leg pain in the older patient

Failure to recognize the presentation frequently leads to misdiagnoses and treatment errors. To avoid such pitfalls, guidelines on seven prominent etiologies are provided. With careful attention to the history and physical examination, an understanding of how those etiologies present will lead to accurate diagnosis and appropriate treatment.

Pentoxifylline in the nonoperative management of intermittent claudication

To assess the clinical effectiveness of pentoxifylline (Trental) in the treatment of intermittent claudication and ischemic rest pain, 129 patients were retrospectively interviewed with respect to compliance and improvement of symptoms. Risk factors for the development of atherosclerosis were tabulated, as was the severity of symptomatic lower extremity peripheral vascular insufficiency. The duration of pentoxifylline treatment was 35.8 +/- 45.0 weeks (mean +/- 1 S.D.). Forty-eight percent of the patients discontinued pentoxifylline on their own, most commonly because of side effects (13%) or perceived lack of improvement (23%). Of those patients taking pentoxifylline for eight weeks or more (n = 110), 64% noted some improvement, with 31% reporting increased claudication distance and 52% reduced claudication pain. Pentoxifylline provided pain relief in 52% of patients with ischemic rest pain (n = 27). Neither diabetes, hypertension, concomitant antiplatelet therapy, the severity of claudication, nor pretreatment ankle-brachial Doppler pressures were related to treatment outcome. Increased daily walking exercise during treatment was associated with successful outcome (p = 0.04). Clinical response to pentoxifylline was inversely related to the number of cigarettes smoked daily in those with 1 block claudication (n = 71, p = 0.05). Pentoxifylline was not very effective in increasing reported claudication distance. This review suggests that pentoxifylline may be of value for patients with ischemic rest pain when arterial reconstruction is not possible. Whether pentoxifylline is useful adjunctive therapy for intermittent claudication requires further scrutiny.

Infusion of a stable prostacyclin analogue, iloprost, to patients with peripheral vascular disease: lack of antiplatelet effect but risk of thromboembolism

PURPOSE

Prostacyclin, a potent inhibitor of platelet function and vasodilator, has been used to treat peripheral vascular disease. The aim of this study was to monitor the thrombotic status of patients treated by infusion of a stable prostacyclin analogue, iloprost.

PATIENTS AND METHODS

Thirteen patients with peripheral vascular disease underwent iloprost infusion for 3 days (8 hours each day) in a dose ranging from 0.5 to 2 ng/kg/minute. Variable parameters of thrombosis such as platelet reactivity (shear-induced hemostatic plug formation and thrombus formation on a collagen fiber), coagulation, and spontaneous thrombolysis (dislodgment of hemostatic plugs) were measured from non-anticoagulated blood samples by hemostatometry immediately before and 1 hour after the infusion and on the last day, 4 hours after initiation of the infusion.

RESULTS

Analysis of data from all patients 1 hour after the infusion showed no changes in platelet reactivity and spontaneous thrombolysis, but coagulation was significantly enhanced. In four patients, significant platelet hyperreactivity was observed after the infusion. Four of the five patients tested while undergoing iloprost infusion showed an enhanced thrombotic reaction and markedly enhanced coagulation. Iloprost employed in vitro in a concentration that corresponds to the therapeutic peak blood level caused no inhibition of platelet function but significantly enhanced coagulation. The threshold in vitro iloprost concentration at which anti-platelet effect and increased spontaneous thrombolysis were observed was twice that of the therapeutic blood level.

CONCLUSIONS

These findings challenge the view that antagonism of platelet function is an important factor of iloprost therapy. Furthermore, platelet hyperreactivity in some patients and markedly enhanced coagulation during and after infusion of iloprost in general, represent a risk of thromboembolism, especially as patients are already in a prethrombotic condition.

The prevalence and one-year outcome of limb arterial obstructive disease in a nursing home population

To assess the utility of bedside diagnostic measures to detect prognostically significant peripheral vascular disease, we examined 60 nursing home residents by physical examination, Doppler sphygmomamometry and pneumatic oscillometry, and recorded the clinical history. Eighty-eight percent of the cases had tibial/brachial arterial systolic pressure indices below 0.95, the lower limit traditionally considered normal. Yet, no more than 5% of the patients carried a previous diagnosis of peripheral vascular disease or had intermittent claudication, leg ulcers or gangrene. Approximately half of the patients had tibial/brachial pressure indices less than 0.7, and one year later in these cases, there was significantly greater morbidity and nearly twice the mortality of patients with less severe disease. We conclude that simple bedside diagnostic tests of arterial disease used in this study discloses a high prevalence of disease in institutionalized elderly patients and identifies a group at particular risk for morbid complications.

Measurement of transstenotic pressure gradient during percutaneous transluminal coronary angioplasty

Obstruction to blood flow is accompanied by a pressure gradient across the obstructed site. In certain clinical settings, magnitude of pressure gradient has been used to judge severity of obstruction, and gradient reduction to judge success of an interventional procedure. In percutaneous transluminal coronary angioplasty (PTCA) the relationships between transstenotic pressure gradient, diameter stenosis, and lesion length are imprecisely known. We therefore examined 4263 sets of measurements in patients who underwent PTCA on single, discrete coronary arterial lesions. Multivariate regression analysis demonstrated that pressure gradient was artifactually elevated by about 12 mm Hg at low values of diameter stenosis but increased by the 4th power of stenosis as expected from fluid dynamics models. Pressure gradient was dampened and relatively constant at values of diameter stenosis of 60% or higher, probably because of total or near-total occlusion of the artery. Lesion length was not found to influence pressure gradient. Reductions in diameter stenosis (delta D) and pressure gradient (delta G) were related nonlinearly, with delta D proportional to the square root of delta G, suggesting that a reduction in gradient is directly proportional to an increase in cross-sectional area of the stenosis. The predictive value of final post-PTCA pressure gradients was found: a final gradient of 15 mm Hg or less predicted a final post-PTCA diameter stenosis of 30% or less, with 75% sensitivity and 29% specificity (p less than .01). The results of this study suggest that (1) pressure gradient as currently measured during PTCA is related to diameter stenosis but not to lesion length (2) reductions in pressure gradient and diameter stenosis are nonlinearly related.(ABSTRACT TRUNCATED AT 250 WORDS)

A non-invasive index of leg arterial perfusion pressure during walking, derived from cutaneous toe temperature

This article describes and evaluates a non-invasive technique for continuous monitoring of hemodynamic changes in the legs during walking. The method involves monitoring of cutaneous toe temperature. In six normal subjects we have shown that, during exercise under carefully controlled conditions, a unique steady-state toe temperature exists for any given leg arterial perfusion pressure, when perfusion pressure is varied by means of an external occluding ankle cuff. Further, we have demonstrated a strong correlation between this external ankle cuff pressure and the time rate of changes of toe temperature during the test-period following occlusion. Correlation coefficients, r1, were between -1 and -0.88 (mean -0.95; standard deviation +/- 0.03) for big toe and between -1 and -0.87 (mean -0.94; standard deviation +/- 0.03) for third toe. We conclude that during walking the time profile of toe temperature changes is a useful index of changes in leg perfusion pressure. Therefore, toe temperature may be used to study the dynamics of leg arterial circulation in atherosclerotic occlusive diseases.

Forefoot capillary filtration rate measured during lowering in normal subjects and in patients with occlusive arterial disease before and after arterial reconstruction

Capillary filtration rate (CFR) was measured by a mercury-in-silastic strain-gauge around the forefoot when the forefoot was lowered 40 cm below heart level. In seven normal limbs, CFR was 0.061 (0.049-0.086) ml (100 g min)-1 against 0.049 (0.016-0.071) ml (100 g min)-1 in 24 limbs with occlusive arterial disease (P = 0.01). About 8 days after arterial reconstruction CFR decreased to 0.039 (0.018-0.071) ml (100 g min)-1, but before 3 months after reconstruction CFR increased to normal values 0.061 (0.037-0.071) ml (100 g min)-1. The explanation offered for the reduced CFR before and immediately after arterial reconstruction is temporary thrombosis in the smallest distributing arteries and in the arterioles resulting in heterogeneous flow distribution and decreased fluid filtration in poorly perfused segments of the capillary bed. The results speak against increased capillary filtration as the aetiology of the post-reconstructive oedema.

Can drugs help patients with lower limb ischaemia?

The prevalence of symptomatic arterial disease of the lower limbs is 2 per cent of the population aged 45-60, but it has a relatively benign course, with 70 per cent of patients requiring no therapy. Of the numerous drugs used in the treatment of the disease, there is no evidence to suggest that antilipaemic drugs, anticoagulants, vasodilators or rheological agents confer any benefit to the patient. The initial use of antiplatelet drugs and prostaglandins has been disappointing despite the undoubted importance of the platelet/endothelial interaction in the aetiology of atherosclerosis. As it is unlikely that we can reverse advanced disease, this is hardly surprising. Long term use of these drugs may prevent deterioration in those patients with progressive disease, and controlled trials on this aspect of treatment are now required. Symptomatic relief in the claudicant may perhaps be obtained with naftidrofuryl and suloctodil and with the former in more severe ischaemia, but their use should not replace the beneficial effects of exercise and cessation of smoking.

Local regulation of blood flow and the occurrence of edema after arterial reconstruction of the lower limbs

The relation between edema after arterial reconstruction of the lower limbs and various potential etiologic factors, including disturbances in local blood flow regulating mechanisms, was investigated in 22 patients with occlusive arterial disease. The occurrence of edema was unrelated to the severity of symptoms as well as to the perioperative changes in distal arterial blood pressure. Postreconstructive edema developed independently of postreconstructive hyperemia and of disturbances in the local vasoconstrictor response to increased venous pressure. The decisive factor for development of edema was the extensive dissection in the thigh and in the popliteal region required for femoropopliteal bypass surgery. Edema developed after nine of nine femoropopliteal bypass operations, and only after one of 12 reconstructions in the aorto-iliac or in the profound femoral segments (p = 0.001). It is concluded that the postreconstructive edema is a lymphedema due to surgical trauma, rather than the result of microvascular derangement.

Occlusive peripheral arterial disease. Guidelines for office management

Occlusive peripheral arterial disease is rather easy to diagnose because of its characteristic symptoms and the ease with which the extremities and their circulation can be examined. Elevation and dependency tests give a rough but reliable estimate of the degree of ischemia, and if more objective data are desired, the systolic blood pressure index can be determined. Management should be individualized according to the degree of disability and ischemia, the expected natural history, and the patient's general health.