No benefit for ASA in asymptomatic peripheral vascular disease

January 01, 0001

No benefit for ASA in asymptomatic peripheral vascular disease

Asymptomatic peripheral vascular disease can be identified by measuring the ankle brachial index (ABI). These British researchers examined the effectiveness of daily aspirin in preventing vascular events in patients with a low ABI found on screening of the general population in the Aspirin for Asymptomatic Atherosclerosis trial. This study was an intention-to-treat double-blind randomized controlled trial conducted from 1998 to 2008 that involved the screening of 28,980 men and women without identified cardiovascular disease living in Scotland. Of those, 3350 with a low ABI (0.95) were entered into the trial. The enrollees received either once daily 100 mg aspirin (enteric coated) or placebo.

The researchers found: "After a mean follow-up of 8.2 years, 357 participants had a primary end point event (13.5 per 1000 person-years). No statistically significant difference was found between groups (13.7 events per 1000 person-years in the aspirin group vs 13.3 in the placebo group, HR-1.03). A vascular event comprising the secondary end point occurred in 578 participants (22.8 per 1000 person-years) and no statistically significant difference between groups (22.8 events per 1000 person-years in the aspirin group vs 22.9 in the placebo group, HR-1.00). There was no significant difference in all-cause mortality between groups (176 vs 186 deaths, respectively, HR-0.95). An initial event of major hemorrhage requiring admission to hospital occurred in 34 participants (2.5 per 1000 person-years) in the aspirin group and 20 (1.5 per 1000 person-years) in the placebo group (HR-1.71)."

The researchers concluded: "Among participants without clinical cardiovascular disease, identified with a low ABI based on screening a general population, the administration of aspirin compared with placebo did not result in a significant reduction in vascular events."

This study, powered to detect a 25% reduction in events, disappointingly found no benefit in administering daily aspirin in people with asymptomatic peripheral vascular disease as measured by ABI.

For the full abstract, click here.

JAMA 303(9):841-848, 3 March 2010 © 2010 the American Medical Associtiation
Aspirin for Prevention of Cardiovascular Events in a General Population Screened for a Low Ankle Brachial Index- A Randomized Controlled Trial. F. Gerald R. Fowkes, Jacqueline F. Price, Marlene C. W. Stewart, et al.

Category: K. Circulatory. Keywords: aspirin, myocardial infarction, stroke, ankle-brachial index, prevention, randomized controlled trial, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 23 March 2010

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