Randomized trial of the effects of low-dose calcium-heparin in patients with peripheral arterial disease and claudication. Italian CAP Study Group

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.

Medical management of critical limb ischaemia: where do we stand today?

Critical limb ischaemia (CLI) is a severe form of peripheral arterial disease (PAD). CLI often causes disabling symptoms of pain and can lead to loss of the affected limb. It is also associated with increased risk of myocardial infarction, stroke and death from cardiovascular disease. The aims of management in patients with CLI are to relieve ischaemic pain, heal ulcers, prevent limb loss, improve function and quality of life and prolong survival. Here, current evidence regarding the medical management of CLI is reviewed. Cardiovascular risk factors should be assessed in all patients with CLI; smoking cessation and treatment of hypertension, hyperlipidaemia and diabetes all reduce the mortality rate in those with PAD. Antiplatelet agents (either aspirin or clopidogrel) are recommended to reduce both the incidence of cardiovascular events and risk of arterial occlusion. By contrast, routine use of anticoagulation (either warfarin or heparin) is not recommended. Treatment of the limbs themselves is often more challenging. Prostanoids may have some efficacy for treating rest pain and for ulcer healing, and iloprost shows favourable results in reducing the risk of major amputations, but long-term follow-up data regarding disease progression are lacking. There is insufficient evidence to support the use of naftidrofuryl or cilostazol, and pentoxifylline is not beneficial. Furthermore, there is no evidence of proven benefit of hyperbaric oxygen. A number of angiogenic growth factors have been studied in Phase I studies and randomized controlled trials (RCTs). They appear to be safe, but efficacy results have been mixed. Treatment with stem cells also shows some potential from early trials, but further larger RCTs are needed to demonstrate clear benefit. Thrombolysis may be an alternative for patients who develop acute limb ischaemia and are unsuitable for surgical intervention. However, newer endovascular techniques are likely to have a greater role in the future.

Antithrombotic therapy in peripheral artery disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline focuses on antithrombotic drug therapies for primary and secondary prevention of cardiovascular disease as well as for the relief of lower-extremity symptoms and critical ischemia in persons with peripheral arterial disease (PAD).

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

The most important of our 20 recommendations are as follows. In patients aged ≥ 50 years with asymptomatic PAD or asymptomatic carotid stenosis, we suggest aspirin (75-100 mg/d) over no therapy (Grade 2B) for the primary prevention of cardiovascular events. For secondary prevention of cardiovascular disease in patients with symptomatic PAD (including patients before and after peripheral arterial bypass surgery or percutaneous transluminal angioplasty), we recommend long-term aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 1A). We recommend against the use of warfarin plus aspirin in patients with symptomatic PAD (Grade 1B). For patients undergoing peripheral artery percutaneous transluminal angioplasty with stenting, we suggest single rather than dual antiplatelet therapy (Grade 2C). For patients with refractory claudication despite exercise therapy and smoking cessation, we suggest addition of cilostazol (100 mg bid) to aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 2C). In patients with critical limb ischemia and rest pain unable to undergo revascularization, we suggest the use of prostanoids (Grade 2C). In patients with acute limb ischemia due to acute thrombosis or embolism, we recommend surgery over peripheral arterial thrombolysis (Grade 1B).

CONCLUSIONS

Recommendations continue to favor single antiplatelet therapy for primary and secondary prevention of cardiovascular events in most patients with asymptomatic PAD, symptomatic PAD, and asymptomatic carotid stenosis. Additional therapies for relief of limb symptoms should be considered only after exercise therapy, smoking cessation, and evaluation for peripheral artery revascularization.

Exercise after heparin administration: new therapeutic program for patients with-option arteriosclerosis oblitrans

BACKGROUND

A prospective study examined whether a combination of an exercise program and heparin administration improves the clinical symptoms of patients with arteriosclerosis obliterans (ASO) without an indication for surgical revascularization because of the lack of distal target vessels or other reasons such as high surgical risk or lack of a vein conduit from previous coronary artery bypass surgery.

METHODS AND RESULTS

A total of 19 consecutive patients with symptomatic non-option ASO diagnosed by angiography were randomly assigned to 3 groups: heparin + exercise (walking for 60 min after heparin injection [3,000 units/day IV for 14 days], n = 6), heparin administration only (n = 6), and exercise only (n = 7). Plasma levels of hepatocyte growth factor (HGF) were serially measured before and after intravenous administration of heparin. Ankle brachial pressure index was measured and treadmill exercise test (2.5 km/h, 12% slope) was performed before the 2-week treatment, just after finishing treatment, and 12 weeks after beginning the treatment. Ophthalmic examinations, including visual acuity test, ocular fundoscopy and fluorescein angiographic fundus photography, were performed before and 12 weeks after the treatment program. In all patients, HGF levels increased more than 4-fold of the basal level at 30 min after heparin injection. Maximum walking time was significantly higher in the heparin + exercise group than in the other 2 groups (p < 0.05). There were no patients who showed pathological retinal angiogenesis.

CONCLUSION

The combination of an exercise program and heparin administration improves the clinical symptoms of patients with non-option ASO.

Effects of simvastatin on walking performance and symptoms of intermittent claudication in hypercholesterolemic patients with peripheral vascular disease

PURPOSE

To analyze the effects of short-term therapy with simvastatin on walking performance in hypercholesterolemic patients with peripheral vascular disease.

METHODS

Eighty-six patients with peripheral arterial disease (Fontaine stage II), intermittent claudication, and total cholesterol levels >220 mg/dL were enrolled in a randomized, placebo-controlled, double-blind study. Forty-three patients were assigned to simvastatin (40 mg/d); the remaining 43 patients were assigned to placebo treatment. All patients underwent an exercise test and clinical examination, and completed a self-assessment questionnaire at 0, 3, and 6 months. Pain-free and total walking distance, resting and postexercise ankle-brachial indexes, and questionnaire scores were determined at each follow-up.

RESULTS

At 6 months, the mean pain-free walking distance had increased 90 meters (95% confidence interval [CI]: 64 to 116 meters; P <0.005) more in the simvastatin group than in the placebo group. Similar results were seen for the total walking distance (mean between-group difference in the change, 126 meters; 95% CI: 101 to 151 meters; P <0.001), and for the ankle-brachial index at rest (mean, 0.09; 95% CI: 0.06 to 0.12; P <0.01) and after exercise (mean, 0.19; 95% CI: 0.14 to 0.24; P <0.005). There was also a greater improvement in claudication symptoms among patients treated with simvastatin. The effects on walking performance, ankle-brachial indexes, and questionnaire scores had also been significant at 3 months.

CONCLUSION

High-dose short-term therapy with simvastatin may improve walking performance, ankle-brachial pressure indexes, and symptoms of claudication in hypercholesterolemic patients with peripheral vascular disease.

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.

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 STRATEGY

Randomised trials of anticoagulants for intermittent claudication were sought using the search strategy described by the Cochrane Peripheral Vascular Diseases Review Group. Additional trials were sought through: reference lists resulting from this search; recent conference proceedings; contact with authors of published trials and pharmaceutical companies producing anticoagulants.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Thirteen trials were initially considered eligible for inclusion in the review. Two studies evaluated oral anticoagulants, five evaluated standard heparin, and six evaluated LMWHs. 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 reviewers extracted the data independently.

MAIN RESULTS

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.

REVIEWER'S CONCLUSIONS

No benefit of heparin, LMWHs or oral anticoagulants has been established for intermittent claudication. An increased risk of major bleeding events has been observed especially with oral anticoagulants. The use of anticoagulants for intermittent claudication cannot be recommended at this stage.