The Association between Multi-Vessel Coronary Artery Disease and High On-Aspirin Platelet Reactivity.

Background: Multi-vessel coronary artery disease (MV-CAD) is correlated with worse clinical outcomes compared with single-vessel CAD (SV-CAD). The aim of this study was to evaluate the association between MV-CAD and high on-aspirin platelet reactivity (HAPR) in patients with stable CAD treated with aspirin. Methods: The current study is an analysis of prospectively enrolled randomly selected patients with known stable CAD, who were taking aspirin (75–100 mg qd) regularly for at least one month, and had undergone coronary angiography at least 3 months prior to the enrollment to the study. Exclusion criteria: acute coronary syndrome at the time of platelet function testing, active malignancy, acute infection, active inflammatory/rheumatic disease, major surgery in the past 6 months, chronic liver failure, treatment with oral anticoagulation, non-adherence with Aspirin and thrombocytopenia (<100 K/micl). Blood was drawn from the participants and sent for platelet function testing (VerifyNow, Instrumentation Laboratory Company, Bedford, Massachusetts, United States). MV-CAD was defined as >50% stenosis in ≥2 separate major coronary territories per coronary angiography. HAPR was defined as aspirin reaction units (ARU) >550. Results: Overall, 507 patients were analyzed; age 66.7 ± 11.2, 17.9% women, 223 (44%) had MV-CAD. The rate of HAPR was significantly higher among patients with MV-CAD vs. SV-CAD (14.8% vs. 3.5%, p < 0.001, respectively). Furthermore, a "dose response"-like association was found between the number of stenotic coronary arteries and the rate of HAPR (3.5%, 13.5 and 17.3% for SV-CAD, 2-vessel and 3-vessel disease, respectively). In a multivariate analysis adjusted for potential confounders, MV-CAD was found to be a strong independent predictor of HAPR [OR = 1.8 (95%CI: 1.05–4.7), p = 0.014]. Conclusions: A significant association between MV-CAD and HAPR was found. Additional studies designed to investigate the mechanisms of HAPR and different therapeutic options for this subset of patients are warranted. [ABSTRACT FROM AUTHOR]