Platelet Larger Cell Ratio and High-on Treatment Platelet Reactivity During Dual Antiplatelet Therapy

Low response to antiplatelet agents has been associated to an increased risk of thrombotic complications and recurrent ischemic events. Platelet size has been proposed as a potential marker of platelet reactivity. Therefore, the aim of the present study was to evaluate the impact of platelet Larger Cell Ratio (p-LCR) on platelet aggregation and the prevalence of residual high-on treatment platelet reactivity (HRPR) in patients receiving dual antiplatelet therapy (DAPT) after a recent acute coronary syndrome or coronary revascularization.

Patients treated with DAPT (ASA and clopidogrel or ticagrelor) were scheduled for platelet function assessment at 30-90 days post-discharge. HRPR was considered for ASPI test >862 AU*min (for ASA) or ADP test values ≥417 AU*min (for ADP-antagonists) using impedance aggregometry.

Our population consisted of 530 patients receiving DAPT, who were divided in tertiles according to values of p-LCR (< 27.6; 27.6-34.7; ≥34.7 l). p-LCR was related with use of beta-blockers (p = 0.02) and statins (p = 0.002), and inversely with acute presentation (p = 0.05). Higher platelet count (p < 0.001) and haemoglobin levels (p = 0.001) were observed in higher p-LCR tertiles. The prevalence of HRPR for ASA was low and not significantly different across tertiles of p-LCR (1.1 vs 1.1 vs 1.7%, p = 0.66; adjusted OR[95%CI] = 1.68[0.66-4.29], p = 0.27). Moreover, p-LCR did not influence the occurrence of HRPR for ADP-antagonists (24.4% vs 20.9% vs 25.6 %%, p = 0.80, adjusted OR[95%CI] = 0.88[0.67-1.17], p = 0.38) and similar results were obtained when considering separately patients receiving clopidogrel (adjusted OR[95%CI] = 1.21[0.86-1.69], p = 0.29) or ticagrelor (adjusted OR[95%CI] = 1.17[0.69-2], p = 0.56).

In patients receiving DAPT for coronary artery disease, p-LCR does not impact platelet reactivity. Larger platelets did not influence the prevalence of high-on treatment platelet reactivity with the antiplatelet agents ASA, clopidogrel or ticagrelor.