Adjustment of Antiplatelet Therapy in Patients With Myocardial Infarction Treated Without Revascularization: A Retrospective Cohort Study

Background

Although a substantial proportion of patients with myocardial infarction (MI) are treated without revascularization, no randomized controlled trial has evaluated the optimal antiplatelet strategy in this vulnerable population and practice patterns may be heterogeneous. This study aims to describe postdischarge antiplatelet therapy (APT) practice patterns in medically managed patients with MI.

Methods

A retrospective cohort study was conducted at the Montreal Heart Institute (July 31, 2020–July 31, 2023). Patients aged ≥18 years hospitalized for MI and discharged without revascularization were included, and discharge antiplatelet patterns were documented.

Results

A total of 365 patients were included, comprising 156 women (42.7%) (median age: 71.4 years [interquartile range: 61-83]). Reasons for being treated without revascularization include MI without obstructive coronary artery disease (n=139; 38%), no angiography performed (n=118; 32%), severe disease not amenable to revascularization (n=71; 20%), small branch disease (n=21; 6%), and spontaneous coronary dissection (n=16; 4%). At discharge, 41.9% (n=153) received dual APT (DAPT), 38.4% (n=140) received single APT, and 19.7% (n=72) received no antiplatelet agent. The most common DAPT regimen prescribed was clopidogrel–acetylsalicylic acid (aspirin) (34.0%; n=124), and the most frequently prescribed antiplatelet monotherapy was aspirin (25.8%; n=94). Among patients treated with DAPT, duration of prescription was 12 months in 91.5% of cases. Postdischarge antiplatelet strategy varied depending on the underlying MI etiology.

Conclusion

Postdischarge antiplatelet strategies prescribed in patients with an MI treated without revascularization are heterogeneous, whereas the preferred strategy is DAPT for 12 months. This variability reflects current clinical equipoise in this understudied population.