May NUI Galway Professor Leads International Debate on the use of Aspirin to Prevent Heart Disease and Stroke

Bill McEvoy, an expert in heart disease prevention who last year returned to Ireland to take up the position of Professor of Preventive Cardiology at NUI Galway and Consultant Cardiologist at Galway University Hospitals, has been invited to debate another international expert on the benefits of aspirin in preventing heart disease and stroke. This debate is important because aspirin is so widely used and because it will also be published in the New England Journal of Medicine, the premier international medical publication, which is widely read by doctors around the world.

Professor McEvoy argues that aspirin continues to have a role in certain patients who are at high risk for heart disease and stroke but who have yet to suffer a clinical manifestation (also known as the ‘primary prevention’ of cardiovascular disease). On the other hand, Professor Sigrun Halvorsen from the University of Oslo in Norway argues that the use of aspirin in primary prevention of cardiovascular is no longer justifiable. Both agree that aspirin should be continued in those who have already suffered a clinical heart attack or stroke, in order to reduce the chances of a recurrence (termed ‘secondary prevention’).

The motivation for this major debate among physicians is based on three recent 2018 clinical trials that suggested aspirin is less effective in the primary prevention of cardiovascular disease than had been previously thought. Older clinical trials, carried out before the turn of the millennium, had demonstrated that aspirin can prevent heart attacks and strokes among adults who were at sufficiently high risk. However, these trials were done at a time when smoking was more common and the treatment of high blood pressure and high cholesterol was less effective than what is available today.

In the 2018 trials, the benefits of aspirin in preventing heart disease and stroke appeared to have been less pronounced in adults treated to current best practice standards (participants in the 2018 trials had much better control of their blood pressure and cholesterol than did the participants in older trials of aspirin). This suggests that aspirin may no longer be necessary for primary prevention as long as cardiac risk factors like smoking, high cholesterol, and high blood pressure are well controlled with modern treatments. Because aspirin causes increased bleeding, particularly in the stomach, there have consequently been arguments to now stop using aspirin for the primary prevention of cardiovascular disease altogether.

However, Professor McEvoy, who also led the review of evidence for aspirin for a recent clinical practice guideline, published by the American Heart Association and American College of Cardiology in March 2019, feels that aspirin continues to have a potential role in some patients. In his pro-argument, he points out that two of the three recent aspirin trials continued to report reductions in non-fatal heart attacks with aspirin use. Furthermore, over a quarter of patients in the recent 2018 trials did not take their aspirin as prescribed, whereas participants in the older studies were much more compliant with the aspirin medication. Therefore, one reason aspirin might not look as good in the recent studies is because the participants simply weren’t taking it. Indeed, when some of the 2018 trials were reanalyzed to look at patients who actually took the aspirin, the reductions in heart attack were even more evident (though these reductions still appear less than in older trials).

Professor McEvoy also argues that, because heart attacks are rarely fatal in a modern era where most patients have a stenting procedure or cardiac surgery to open the blood vessel blockage that caused the heart attack, the benefits of aspirin may take a longer time than previously thought to become evident (specifically less non-fatal heart attacks might translate into less heart failure over prolonged follow-up) and that the results of these 2018 trials (which only reported results after five years of follow-up) will need to be extended to 10 or more years before it is known for sure that aspirin is not as effective as previously thought.

Ultimately, McEvoy feels the ball should be in the patient’s court. If, after discussing the risks and benefits of aspirin with their doctor, the patient prefers to prevent a heart attack than a bleeding episode (most of which are minor) and if the patient’s risk for cardiovascular disease is sufficiently high, then McEvoy feels it is reasonable to continue recommending aspirin for now- though with annual reassessment of the pros and cons.

In a statement Professor Bill McEvoy, NUI Galway and Galway University Hospitals, said: “As an Irish physician, its great to be invited to lead this international debate among physicians around the world. I’m proud that Galway and Ireland are flying the flag of heart disease and stroke prevention and this article is great exposure for the research we are carrying out at NUI Galway and the National Institute of Preventive Cardiology, also based in Galway.”

Professor McEvoy has also been invited to write an extended review on this topic for another leading medical journal, The Lancet, which is due to be published on 25, May 2019.

To read the full debate in New England Journal of Medicine on Wednesday, 15 May 2019 at 5pm EST, visit: https://www.nejm.org

-Ends-