At the European Society for Cardiology Congress this week, we learned about more situations where aspirin is unhelpful. Professor Gerry Fowkes and colleagues from Edinburgh looked at nearly 30000 men and women aged 50 to 80 years who had never had any cardiovascular disease, but had a low ankle-brachial pressure index, a marker of peripheral vascular disease. The ankle brachial index (ABI) is the ratio of the blood pressure in the arm to the blood pressure at the ankle, and is an indicator of subclinical atherosclerosis. The ABI predicts risk of major vascular events in healthy populations, independently of established cardiovascular risk factors, such as diabetes, smoking and cholesterol. The Edinburgh team recruited over 3000 people with low ABI from their population and randomised them to 100mg aspirin or placebo, with 8 years of follow-up.

There was no difference between aspirin and placebo whether we look at cardiovascular events or all cause mortality, and there were more major bleeds in the aspirin arm of the trial. Same bottom line as before: do not give aspirin to people before they have a vascular event.

Since medical school, I have always been struck by the number of patients of all ages who live life by the “aspirin-a-day” mantra. In people who have had heart attacks or strokes, aspirin reduces further events by 25%. This beneficial effect is known as “secondary prevention”, and outweighs aspirin’s bleeding risk [1, 2].