Associations Between PFA-Measured Aspirin Resistance, Platelet Count, Renal Function, and Angiotensin Receptor Blockers

Aspirin resistance is used to describe patients who are undergoing aspirin therapy but fail for the inhibition of thromboxane biosynthesis in platelets. Although the true mechanism is unclear, drug–drug interaction remains a possible factor. The study aimed to determine whether there was association between aspirin resistance and the concomitant cardiovascular medication. Using the Platelet Function Analyzer-100 system, aspirin resistance was evaluated in aspirin-treated patients from the outpatient department. The associations between aspirin resistance and their concomitant common cardiovascular medication were analyzed. Aspirin resistance was prevalent in 147 (17.7%) of 831 patients. Concomitant angiotensin receptor blocker (ARB) treatment and low platelet count were associated with aspirin response (P = .04, .02, respectively). Multivariate logistic regression analysis results showed an association between aspirin response and ARB therapy (adjusted odds ratio [OR] 1.48; 95% confidence interval, CI: 1.08-2.18). And the association was blunted when platelet count was considered (adjusted OR 1.43, 95% CI: 0.92-2.23). In ARB-treated patients, increased creatinine and decreased hematocrit laboratory data increased the risk of aspirin resistance (P = .02, .04, respectively), and the effect of platelet count on aspirin resistance was diminished by ARB therapy. Concomitant ARB treatment in aspirin-treated patients decreased the risk of aspirin resistance, and the effect was dependent on low platelet count. In ARB-treated patients, increased creatinine and decreased hematocrit data increased the risk of aspirin resistance. In addition, the effect of platelet count on aspirin resistance was diminished by ARB treatment.