Abstract
Purpose: Calcium channel blockers (CCBs) do not reduce the risk of initial or recurrent myocardial infarction (MI) in patients diagnosed with stable coronary artery disease (CAD). The aim of this current study was to evaluate the association between CCBs and aspirin resistance in patients with CAD. Methods: Patients with stable CAD who were regularly taking aspirin (75-100 mg qd) for at least one month prior to enrollment in the study were included. The VerifyNow system was used for platelet function testing with high on-aspirin platelet reactivity (HAPR) defined as aspirin reaction units (ARU) >550. We compared patients treated with CCBs versus control group. Results: 503 patients with CAD were included in this study, 88 were treated with CCBs; Mean age (67.9±9.7 in the CCB group vs 66.5±11.4 in the control group, p=0.288), gender (77.3 male vs. 82.9%, p=0.214) and rates of diabetes mellitus (34.7 vs. 36.9%, p=.121) were similar. Rates of hypertension were higher in the CCB group (83.9 vs. 63.5%, p<0.01), but rates of past MI were lower (47.1 vs. 59.7%, p=0.039). The mean ARU was 465.4P70.0 for patients treated with CCBs versus 445.2u60.0 in controls (p=0.006). Similarly, 15.9% of CCB patients demonstrated HAPR compared to 7.0% (p=0.006). In a multivariate analysis, the administration of CCBs was independently associated with HAPR (OR- 1.72, 95% CI 1.04 – 8.91, p=0.047). Conclusions: Usage of CCBs is positively correlated with aspirin resistance. These findings may suggest an adverse pharmacologic effect of CCBs among patients with stable CAD treated with aspirin.
Impact of Calcium Channel Blockers on Aspirin Reactivity in Patients with Coronary Artery Disease
