A 67-year-old male patient with history of coronary artery disease with prior percutaneous coronary intervention (PCI) of the mid left anterior descending artery in March 2020, hypertension, hyperlipidemia, type 2 diabetes mellitus, and chronic kidney disease stage 2 presents to his primary cardiologist for follow-up. His current medications include aspirin 81 mg daily, atorvastatin 80 mg daily, lisinopril 10 mg daily, metoprolol succinate 25 mg daily, and metformin 500 mg daily.
In early 2020, he presented to the emergency department with chest pain at rest. His physical exam was unremarkable; however, he was found to have ST depression in V2-V4 on his electrocardiogram and an elevated high-sensitivity troponin. He was taken to the cardiac catherization laboratory where coronary angiography revealed severe stenosis of his mid left anterior descending artery. He underwent PCI with placement of a drug-eluting stent. Subsequently, he was chest-pain free and discharged from the hospital the next day. Echocardiography during the hospitalization revealed no major abnormalities in ventricular function and preserved ejection fraction. He completed a 12-month course of dual antiplatelet therapy with a P2Y12 receptor inhibitor, ticagrelor, and aspirin 81 mg with no complications. Afterwards, ticagrelor was discontinued, and he remained on aspirin monotherapy.
Now in clinic, he reports that since discontinuing the ticagrelor, he has remained free of chest pain and is able to complete his daily activities without limitation. He is adherent to all his prescribed medications and purchases his aspirin over the counter at the local drugstore. On examination, his heart rate is 67 bpm, and blood pressure is 115/72 mmHg. The remainder of the exam is unremarkable. At the end of the clinic visit, the patient asks if he should switch to high-dose 325 mg aspirin given his recent heart attack.
The correct answer is: A. Continue aspirin 81 mg daily
This patient has chronic, stable atherosclerotic cardiovascular disease (ASCVD) with prior myocardial infarction. Over the last several years, there has been a paradigm shift toward low-dose aspirin even without randomized clinical trial data to support these changes. The most recent European guidelines give a Class IA recommendation for daily low-dose aspirin for patients with chronic ASCVD.1,2
Results from the recent ADAPTABLE (Aspirin Dosing: A Patient-Centric Trial Assessing Benefits and Long-Term Effectiveness) study used a real-world environment to show that treating patients with ASCVD with low-dose 81 mg aspirin is as effective as using the higher dose 325 mg for the prevention of major adverse cardiovascular events.3 There was also poorer adherence to the higher-dose aspirin, which is supportive of starting and continuing lower-dose aspirin in this patient population. The gastrointestinal side effects of aspirin are thought to be more prevalent in higher doses of aspirin; however, the results of ADAPTABLE showed no difference in major bleeding between the doses.
Ultimately, the ideal dose of aspirin for chronic and stable ASCVD is 81 mg as supported by recent evidence; therefore, answer A is correct, and the majority of patients should not switch doses of aspirin. At this point, there is not sufficient evidence for antiplatelet monotherapy with ticagrelor (answer C), although studies are ongoing about alternative strategies that do not involve aspirin. Answer D is not correct because there is not good evidence to support full-dose ticagrelor therapy for longer than 12 months post-PCI, and, if utilized, the more appropriate dose would be 60 mg twice daily per the PEGASUS-TIMI 54 (Prevention of Cardiovascular Events in Patients With Prior Heart Attack Using Ticagrelor Compared to Placebo on a Background of Aspirin–Thrombolysis in Myocardial Infarction 54) trial results.
References
- Knuuti J, Wijns W, Saraste A, et al. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes. Eur Heart J 2020;41:407-77.
- Hall HM, de Lemos JA, Enriquez JR, et al. Contemporary patterns of discharge aspirin dosing after acute myocardial infarction in the United States: results from the National Cardiovascular Data Registry (NCDR). Circ Cardiovasc Qual Outcomes 2014;7:701-7.
- Jones WS, Mulder H, Wruck LM, et al. Comparative Effectiveness of Aspirin Dosing in Cardiovascular Disease. N Engl J Med 2021;384:1981-90.
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