August 21, 2023 Author : José Ferreira Santos It is increasingly common in medical appointments that patients ask about the need or benefits of taking aspirin to prevent a heart attack or other cardiovascular event. The answer is not always simple, there are multiple factors to consider, for example: History of cardiovascular disease, general health history, family health history and other individual characteristics of each person; Other medicines and respective mechanisms of action; International recommendations, based on scientific knowledge and history of use. The name Aspirin Aspirin is the commercial designation (or trademark) that the pharmaceutical company Bayer gave, at the end of the 19 th century, to its medicine containing acetylsalicylic acid as active ingredient. Acetylsalicylic acid was discovered in 1853; A few years later, Bayer began marketing Aspirin, to control pain (analgesic effect) and inflammation (anti-inflammatory effect). The great popularity that Aspirin achieved caused the brand name to be used widely to refer to medicines with acetylsalicylic acid, even when there were already other medicines containing the same active ingredient, from other laboratories and with other brands. Cardiovascular effects of aspirin In the 1950s, after years of using Aspirin to relieve pain and control inflammation, it was realized that it could have other effects, namely in the treatment of myocardial infarction and other events related to the formation and circulation of blood clots. In a dose different from that which has analgesic and anti-inflammatory effects – the so-called low dose, which varies between 75-150 mg/day – aspirin started to be used as a medicine with antiplatelet effects: Platelets are one of the types of blood cells; The sticking of platelets is part of the normal mechanism of blood clotting in case of bleeding; Some cardiac events, such as acute myocardial infarction and stroke (cerebrovascular accident) are due to the formation and circulation of blood clots, obstructing the arteries. The antiplatelet effect of aspirin prevents the formation of blood clots and that is why it may be indicated to protect and reduce the risk of cardiac events, in low doses. And its intake by people with established cardiovascular disease has become widespread. Results of aspirin use in established cardiovascular disease Over the years, multiple studies have been conducted that have demonstrated what are now established benefits of aspirin: When administered in the acute phase of acute myocardial infarction or stroke, aspirin reduces the risk of mortality from these diseases: For example, in one of the first studies with aspirin in patients with myocardial infarction, ISIS-2, it was found that the administration of aspirin for one month reduced the probability of death by 23%! When given long-term to patients who have established cardiovascular disease, aspirin reduces the risk and increases the likelihood of event-free survival: On average, a patient taking a low dose of aspirin reduces the risk of having a new event by about 20%! When arterial revascularization procedures are performed (for example, coronary bypass surgery, carotid or coronary angioplasty, among others), aspirin is an obligatory complement to the treatment and can even be combined with other antiplatelet drugs. The YES answer This is the simplest answer to the question of taking aspirin when it comes to secondary prevention. In most of the following cases, taking aspirin (or another antiplatelet agent) is part of the mandatory treatment: Acute myocardial infarction; Ischemic stroke; Peripheral arterial disease, Angina pectoris; History of angioplasty; Coronary bypass surgery; Another cardiovascular disease related to atherosclerosis. Naturally, among people who have these problems there may be exceptions and therefore the decision should always be made by a doctor. Aspirin in the primary prevention of cardiovascular events The excellent results obtained and the experience of using aspirin, for several years, in patients with established cardiovascular disease, made doctors and scientists begin to study the impact on the primary prevention of cardiovascular events, that is, in people who had never had a cardiovascular event. Meanwhile, the concept was established that aspirin protects the heart. The truth is that it reduces the risk of myocardial infarction and, as such, it can even be taken by healthy people to increase the possibility of surviving without cardiovascular events. In many countries, aspirin has been sold over-the-counter for many years now, and everyone can freely choose whether or not to take aspirin! For their part, physicians, began to prescribe aspirin more liberally. In a sense, aspirin has become a longevity drug, whose role has become difficult to question. The accumulated knowledge, both from research and from the use of aspirin by millions of people, allows a rigorous answer to the question whether or not we should take aspirin to prevent cardiovascular events, but not in the same way for everyone, particularly in the case of primary prevention. The answer IT DEPENDS, IT MAY NOT BE THE BEST OPTION This is the answer in the case of primary prevention, that is for those who have not had cardiovascular events and have not been diagnosed with any heart disease, which means that preventing something in someone who is potentially healthy. What do the three most recent studies tell us about the use of aspirin in primary prevention, that is, in people who have never had a cardiovascular event: In older patients over 70 years of age without cardiovascular disease, aspirin medication (ASPREE main results): Did not reduce the risk of cardiovascular events or increase years of life; Increased the risk of bleeding by 38%. In middle-aged patients over 55 years of age with cardiovascular risk factors (eg tobacco use, high blood pressure and high cholesterol) but no established cardiovascular disease, aspirin medication (ARRIVE main results): Did not reduce the risk of cardiovascular events; Increased the risk of bleeding by about two times. In diabetics, over 40 years of age and without cardiovascular disease, aspirin medication (ASCEND main results): Reduced the risk of events by 12%; Increased the risk of bleeding by 29%, negating the benefit achieved. When used in primary prevention, the summary of 13 clinical trials, with 164,225 participants, indicates that aspirin preventive medication produces the following results: 0.41% absolute reduction in the risk of having a serious cardiovascular event (including death, myocardial infarction or stroke); 0.47% absolute increase in the risk of having a major bleed; That is, in practice, the benefit in reducing the risk of cardiovascular events is offset by the risk of severe bleeding. These studies do not tell the whole story of aspirin and even in primary prevention, there may be patients who benefit from the medication. These are patients who have many risk factors and a high probability of having a heart attack or stroke even though they have not yet had an event; These are what physicians call patients at high cardiovascular risk who may benefit from preventive aspirin therapy. In conclusion Taking aspirin to prevent heart attacks and other cardiovascular events? Talk to your doctor, but in most cases: Yes, if you have or had: Acute myocardial infarction Ischemic stroke Peripheral arterial disease History of angioplasty History of coronary bypass surgery Other cardiovascular disease related to atherosclerosis No , if you: Are healthy (has not had any of the problems mentioned above); Are over 70 years old or under 40 years old; Have an increased risk of bleeding due to any concomitant illness. Perhaps , your doctor will decide, if: You have a high cardiovascular risk. You must also remember that with regard to cardiovascular prevention, measures associated with lifestyle are as or more important than the discussion about whether or not to take aspirin! References Baigent C, Blackwell L, Collins R, Emberson J, Godwin J, Peto R, et al. Aspirin in the primary and secondary prevention of vascular disease: collaborative meta-analysis of individual participant data from randomised trials. Lancet. 2009;373:1849-60. Jacobsen AP, Raber I, McCarthy CP, Blumenthal RS, Bhatt DL, Cusack RW, et al. Lifelong aspirin for all in the secondary prevention of chronic coronary syndrome: still sacrosanct or is reappraisal warranted? Circulation. 2020;142:1579-1590. Miner J, Hoffhines A. The discovery of aspirin's antithrombotic effects. Tex Heart Inst J. 2007;34:179-86. Patrono C, Baigent C. Role of aspirin in primary prevention of cardiovascular disease. Nat Rev Cardiol. 2019;16:675-86. doi: 10.1038/s41569-019-0225-y. Peters AT, Mutharasan RK. Aspirin for prevention of cardiovascular disease. JAMA. 2020;323:676. Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. Lancet 1988;2:349-60. Zheng SL, Roddick AJ. Association of aspirin use for primary prevention with cardiovascular events and bleeding events: a systematic review and meta-analysis. JAMA. 2019;321:277-87. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
