Resident Université de Montréal Montréal, Quebec, Canada
Background: The use of acetylsalicylic acid (ASA) for secondary prevention of obstructive atherosclerotic coronary artery disease (CAD) is well established. However, there are no recommendations or evidence supporting its use in subclinical (non-obstructive) CAD. The objective of this study is to describe ASA prescribing trends in this population.
METHODS AND RESULTS: A single-center, retrospective observational cohort study was conducted between January 1st and December 31st, 2022, at the Montreal Heart Institute. The study included patients who underwent elective coronary angiography showing subclinical CAD, defined as < 50% stenosis of the left main coronary artery, < 70% stenosis in other territories, or non-significant lesions based on interventional assessment tools. Patients were excluded if they had a history of peripheral or cerebral vascular disease, a history of heart surgery, or a new or past history of acute coronary syndrome (ACS) or percutaneous coronary intervention. The primary outcome was ASA prescription within 30 days post-coronary angiography. Secondary outcomes included ASA prescription between 31 and 365 days post-coronary angiography and the occurrence of an event (ACS, revascularization, or mortality) in the year following coronary angiography.
Of the 1,390 electronic medical records reviewed, 395 patients, with a mean age of 68.8 ± 10.5 years, were included. 59.7% were men and more than half of them were known for hypertension, dyslipidemia or valvular diseases. 53.7% of these patients underwent coronary angiography for preoperative evaluation, 35.9% for investigation of stable angina, and 10.3% for other reasons. ASA was prescribed to 13.2% of patients within the first 30 days and to 23.8% between 31 and 365 days post-coronary angiography. A total of 38.7% of patients were already taking ASA and continued its use. During the year following their procedure, 20 patients — 18 of whom were on ASA — experienced an event. Independent predictors of ASA prescription, identified through multivariable logistic regression, included male sex (p = 0.04), history of dyslipidemia (p = 0.032), history of stage 3 to 5 chronic kidney disease (p = 0.016), absence of atrial fibrillation/flutter (p < 0.001), and suspected stable angina as the indication for coronary angiography (p = 0.01).
Conclusion: At a quaternary cardiology centre, approximately 75% of patients with subclinical CAD either continued taking or were prescribed ASA within a year post-angiography. Randomized studies are needed to better define its role in subclinical CAD.
