# Aspirin Use in Secondary Prevention of Myocardial Infarction: A Systematic Review and Meta-Analysis

## TL;DR

This study reviews aspirin's effectiveness in preventing heart attacks and finds that while it works, newer treatments may offer better safety and outcomes for some patients.

## Contribution

The study provides updated evidence on aspirin's role and compares it with newer antiplatelet therapies for secondary heart attack prevention.

## Key findings

- Aspirin reduced recurrent heart attacks by 19% but increased bleeding risk, especially at higher doses.
- P2Y₁₂ inhibitors showed similar effectiveness with lower bleeding risk compared to aspirin.
- Personalized strategies, such as 81 mg aspirin or P2Y₁₂ inhibitors for high-bleeding-risk patients, improved outcomes.

## Abstract

Aspirin is widely used for secondary prevention of myocardial infarction (MI), but its comparative efficacy against newer antiplatelet regimens remains debated. This study, therefore, aimed to evaluate aspirin’s role in secondary MI prevention by assessing its effectiveness, safety, and potential alternatives. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant meta-analysis, including 14 studies (n = 327,987) published between 2000 and 2024, was conducted. Random-effects models were applied to pool risk ratios (RRs) for cardiovascular events and bleeding outcomes. Subgroup analyses were performed according to dosing, comorbidities, and treatment strategies. Aspirin reduced recurrent events by 19% (RR: 0.81, 95% CI: 0.78-0.84) but increased bleeding risk, particularly at the 325 mg dose. P2Y₁₂ inhibitors demonstrated comparable efficacy with lower bleeding risk (HR: 0.56-0.95). Extended dual antiplatelet therapy (DAPT) benefited high-risk patients, such as those post-percutaneous coronary intervention (PCI) (HR: 0.85, 95% CI: 0.75-0.96) and those with diabetes (HR: 0.86, 95% CI: 0.75-0.99), but was associated with higher bleeding risk (HR: 1.3-1.8). Monotherapy exhibited lower heterogeneity (I² = 46.75%) than dual therapy (I² = 70.31%). Overall, aspirin remains a cornerstone of secondary prevention. Still, personalized strategies-favoring 81 mg dosing, P2Y₁₂ inhibitors in patients at high bleeding risk (HBR), and time-limited DAPT in those at high ischemic risk-appear to optimize outcomes.