Relation between the Change in Mean Platelet Volume and Clopidogrel Resistance in Patients Undergoing Percutaneous Coronary Intervention

We aimed to determine the association between the change in mean platelet volume (MPV) over time and aspirin/clopidogrel resistance in patients undergoing percutaneous coronary intervention (PCI). The MPV and platelet function were analysed in 302 patients who underwent PCI. MPV changes were associated with increased aspirin reaction units (ARU, r = 0.114; P = 0.047), increased P2Y12 reaction units (PRU, r = 0.193; P = 0.001), and decreased P2Y12% inhibition (PI%, r = 0.273; P < 0.001). The group with increasing MPV values showed significantly higher PRU values and lower PI% compared with the group with decreasing MPV values (222.5+/- 73.9 vs. 195.6+/- 63.7 PRU, P = 0.001; 24.1+/-21.0 vs. 32.8+/- 18.5 PI%, P < 0.001, respectively). The clopidogrel resistant group (>= 235 PRU or <= 15% of PI%) showed a significantly higher positive change in MPV (Delta MPV) values than the clopidogrel responder group (0.53+/- 0.78 vs. 0.13+/- 0.69 fL, P < 0.001). When the Delta MPV cut-off level was set at 0.20 fL using the receiver operating characteristic curve, the sensitivity and specificity for differentiating between the clopidogrel resistant and responder groups were 72.6% and 59.3%, respectively. After adjusting for traditional risk factors, the odds ratio in the clopidogrel resistant group with Delta MPV >= 0.2 fL was 4.10 (95% confidence interval; 1.84-9.17). In conclusion, Delta MPV was associated with PRU and PI%; a positive Delta MPV was an independent predictive marker for clopidogrel resistance after PCI.