Another study has cast doubt on the role of aspirin in primary prevention. The Aspirin for Asymptomatic Atherosclerosis trial showed no reduction in vascular events with aspirin in asymptomatic subjects with a low ankle brachial index (ABI). Men and women aged 50-75 years living in central Scotland were invited for ABI screening for asymptomatic atherosclerosis over a ten-year period from 1998 to 2008. A total of 28,980 patients were screened of which 3,350 had a low ABI and were randomised to aspirin 100mg or placebo. Patients were followed up for a mean of 8.2 years.'There is little doubt that aspirin is beneficial in patients with symptomatic cardiovascular disease or with a history of stroke but this trial adds further weight to the reluctance to use aspirin for primary prevention in asymptomatic patients even in those considered at high risk with little evidence of benefit and some evidence of harm.'