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Aspirin has benefit in peripheral arterial disease

Is low-dose aspirin effective in preventing serious vascular events in patients with peripheral arterial disease?

Is low-dose aspirin effective in preventing serious vascular events in patients with peripheral arterial disease?


The original plan for this study was to recruit a sample of 2,000 patients with peripheral arterial disease.

However, this became difficult because of widespread aspirin use for other indications, and recruitment was therefore stopped at 366 patients.

A serious vascular event was defined as a fatal or nonfatal myocardial infarction or stroke, or death that could not be ascribed to a nonvascular cause such as cancer.

Critical leg ischaemia was defined as ischaemic pain at rest for more than two weeks, with or without ulcers or gangrene, plus ankle and toe blood pressure criteria.

Patients were randomised to four groups: aspirin 100mg daily, antioxidant vitamins (vitamin E 600mg, vitamin C 250mg, and ß-carotene 20mg), both, or neither. Patients with diabetes were included.

Patients were followed up every three months for two years. There was a significant reduction in major vascular events in the aspirin-treated groups: seven of 185 versus 20 of 181 (4% versus 11%; P = 0.02; numbers needed to treat [NNT] = 14; 95% CI, 8-53). C

ritical leg ischaemia occurred in 2.7% of aspirin-treated patients versus 4.4% of placebo patients (not significant). As in other studies there was no benefit with antioxidant vitamins. Neither treatment was associated with an increase in adverse events in this small study.

Level of evidence

1b (see loe.cfm)


Critical Leg Ischaemia Prevention Study (CLIPS) Group; Catalano M, Born G and Peto R. Prevention of serious vascular events by aspirin among patient with peripheral arterial disease: randomised, double-blind trial. J Int Med 2007;261:276-84.

Bottom line

Low-dose aspirin prevents major vascular events in patients with peripheral arterial disease with an NNT of 14 for two years.

The study was too small to assess whether there is a risk reduction in critical leg ischemia events.

Many of these patients have an indication for aspirin based on the presence of established coronary artery disease or diabetes.

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