Aspirin Resistance in Coronary Artery Disease: Prevalence and Clinical Implications

Introduction: Coronary artery disease (CAD) remains a major cause of morbidity and mortality worldwide. Aspirin is a cornerstone in CAD management due to its antiplatelet effects; however, aspirin resistance can lead to suboptimal outcomes. In Iran, limited data exist regarding the prevalence of aspirin resistance among patients presenting with chest pain. This study aimed to determine the prevalence of aspirin resistance and its clinical implications in a cohort of Iranian patients with CAD. Methods: This prospective cross-sectional study was conducted in 2021 at the Emergency Department of Imam Hossein Hospital, Tehran, Iran. A total of 155 patients aged ≥ 18 years on daily aspirin therapy ( ≥ 75 mg for ≥ 7 days) were recruited using convenience sampling. Bleeding time was measured by the standard SimPlate method (resistance defined as BT < 5 minutes). Normality of variables was tested with the Shapiro–Wilk test; between-group comparisons were performed using the t-test for continuous variables and the χ² test for categorical variables. Statistical significance was defined as P < 0.05. Results: Among 155 participants (mean age 57.49 ± 13.13 years; 59.4% male), 133 (85.8%) exhibited aspirin resistance. Resistant patients were significantly older than sensitive ones (59.64 ± 12.47 vs. 44.50 ± 9.05 years; P < 0.001). No gender difference was observed (P = 0.363). Compared with aspirin-sensitive patients, resistant patients had higher rates of hypertension (42.1% vs. 18.2%; P = 0.033), diabetes mellitus (42.9% vs. 9.1%; P = 0.003), and hyperlipidemia (32.3% vs. 0%; P = 0.002). Finally, hospitalization was more frequent in resistant patients (81.2% vs. 22.7%; P < 0.001). Conclusion: These findings indicate that aspirin resistance is prevalent among Iranian CAD patients and is strongly associated with older age and increased cardiovascular risk factors, underscoring its clinical significance. Routine screening for aspirin resistance should be integrated into CAD management protocols, enabling personalized antiplatelet strategies and ultimately improving patient outcomes.