Mean platelet volume and high-residual platelet reactivity in patients receiving dual antiplatelet therapy with clopidogrel or ticagrelor

Objective: High on-treatment platelet reactivity (HRPR) is associated with a two-to ninefold increased risk of recurrent ischemic events among patients receiving dual antiplatelet therapy (DAPT) for coronary artery disease. However, its determinants are still poorly understood. The aim of the present study was to assess the impact of mean platelet volume (MPV) on platelet reactivity in patients receiving DAPT after an acute coronary syndrome or PCI. Methods: Patients treated with DAPT (acetylsalicylic acid [ASA] and clopidogrel or ticagrelor) were scheduled for platelet function assessment at 30 - 90 days post-discharge. By whole blood impedance aggregometry, HRPR was considered for ASPI test > 862 aggregation units (AU)*min (for ASA) and ADP test values 417 AU*min (for ADP-antagonists). Results: Our population is represented by a total of 487 patients on DAPT, divided according to MPV tertiles (< 10.4 fl; 10.4- 11.29 fl; >= 11.3 fl). Larger-sized platelets were associated with use of statins (p < 0.001) and beta-blockers (p = 0.03), higher hemoglobin levels (p = 0.002) and lower platelets count (p < 0.001). Higher platelet reactivity was observed at ASPI test in patients with higher MPV (r = 0.12, p = 0.008), but not for ADP-mediated aggregation (r = -0.007, p = 0.88). However, a low prevalence of HRPR was observed with ASA, with no impact of MPV tertiles (1.2 vs 1.1 vs 1.6%, p = 0.70, adjusted OR [95% CI] = 1.05 [0.51 - 1.77], p = 0.87). MPV did not influence the prevalence of HRPR for ADP-antagonists (25.9 vs 1 vs 26.5%, p = 0.89; adjusted OR [95% Cl] = 1.1 [0.84- 1.45], p = 0.50) with similar results among the 259 patients receiving clopidogrel (adjusted OR [95% Cl] = 1.15 [0.82- 1.62], p = 0.43) and the 228 patients on ticagrelor (adjusted OR [95% Cl] = 1.46 [0.84- 2.55], p = 0.18). Conclusion: In patients receiving DAPT, MPV does not affect the response to major antiplatelet therapies. In fact, MPV elevation does not influence the risk of HRPR with clopidogrel, ticagrelor or ASA.