ASPIRIN IN HEART HEALTH: PART 2

Aspirin in primary prevention, BEFORE a cardiovascular event.

IN

the previous article entitled

Aspirin in Heart Health Part 1, the importance of using aspirin in secondary prevention was discussed. Secondary prevention is stopping or reducing the risk of a second event such as a further heart attack or stroke. However, giving aspirin to people before they have an event, i.e. in primary prevention, has caused controversy over subsequent years. Does giving aspirin in primary prevention offer any benefits in hear health? In the last three to six months, a number of trials have tried to answer this question. In August 2018, a study called ASCEND was published in the New England Journal

of Medicine. This trial studied patients who were diabetic, but had not had any history of heart problems, i.e. they were a primary prevention population. These patients, 15,000 of them were in fact followed for over seven years and although at the end of that time, there was some suggestion that the risk of having a heart attack was reduced in the group receiving aspirin, this benefit was offset by an increased risk of bleeding caused by taking aspirin for a long term. There was an increased risk of bleeding from the upper part of the gut or of bleeding into the brain. Unfortunately, the ASCEND trial did not show a benefit in giving aspirin for a group of diabetic patients, who had not had previous heart problems.

Released at the same time as the ASCEND trial results, a study called ARRIVE published in The Lancet, showed that aspirin had no significant benefit in outcome when given to 13,000 subjects randomised to take aspirin or not. These

were people with ‘moderate cardiovascular risk’ but had not had a previous heart attack or stroke. Moderate cardiovascular risk means that the risk of an event in the next ten years is between 10 and 20% risk. This group of patients was followed for approximately six years and during that time any benefits in reduction of stroke or heart attack were matched by complications of bleeding. The most recent trial for aspirin, studied for its role in ‘primary prevention’, was the

ASPREE trial. Primary prevention deals with delaying or preventing the onset of a cardiovascular event. Nearly 20,000 people across the world were enrolled to try and evaluate whether aspirin given to otherwise healthy older adults, over 70 years of age, would improve function and reduce death. These participants in the trial were followed

for approximately six years and there was no suggestion that giving aspirin to this healthy group of older citizens made any difference. In fact, there was even a small suggestion that it could worsen the outcome. It is worth noting that these healthy older adults had lived to be healthy older adults, because they did not have coronary artery or cardiovascular disease up to that point and so to some degree, the group already had a relatively low risk to benefit from aspirin, in the context of reducing cardiovascular risk.

SO WHERE DOES ALL THIS INFORMATION LEAVE US NOW?

It would certainly seem that aspirin should not just be tried to reduce risk of heart attack and stroke for everyone. It certainly does not have a clear-cut use in normal primary preventative situations of low or moderate/intermediate risk patients. There is some data to suggest that patients with elevated blood pressure may well benefit from being on aspirin and that is because elevated blood pressure can push people into a higher risk category.

I tend to try and be more precise about how to evaluate the risk that an individual may have in the primary preventative setting by undertaking imaging of their coronary arteries. None of the primary prevention studies as above, have incorporated imaging as a selector for aspirin therapy or not, so the use of imaging in primary prevention by aspirin remains somewhat unanswered and speculative. However, if we find people with high or very high-risk features on imaging, then understanding the pros and cons of aspirin based on the individual’s situation, the use of aspirin may well be a reasonable consideration. This is something that needs to be considered on a patient to patient basis with all the information available and with a clear conversation between doctor and patient striving for the best management strategy for that individual. I have written a book on this very subject.

When it comes to secondary prevention i.e. people who have had a heart attack or stroke, there remains no question that aspirin is beneficial, and these current trials do not impact or alter the way we view aspirin in that situation. This means that if you have had a problem with your heart arteries, neck arteries or arteries in the legs and you have been put on aspirin by your doctor, then that aspirin is going to be doing a good job for you. Please do not stop your therapy based on the way some media outlets have presented the data from ASCEND,

ARRIVE and ASPREE, check if it relates to your condition. Every treatment needs to be considered for the individual patient based on the merits of benefit of that therapy, weighed up clearly against the risks that could be inherent. This is something that your doctor needs to work through with you and something you need to be aware of and informed of. Please work with your doctor for your own best outcomes.