Thrombin-induced platelet-fibrin clot strength: relation to high on-clopidogrel platelet reactivity, genotype, and post-percutaneous coronary intervention outcomes.

The relationship between thrombin-induced platelet-fibrin clot strength (MATHROMBIN), genotype and high on-treatment platelet reactivity (HPR) is unknown. The aim of this study is to assess the influence of MATHROMBIN measured by thrombelastography on HPR and long-term major adverse cardiovascular events (MACE) in percutaneous coronary intervention (PCI)-treated patients during aspirin and clopidogrel therapy. MATHROMBIN, platelet aggregation, genotype, and two-year MACE were assessed in 197 PCI-treated patients. HPR was defined as 5 µM ADP-induced PR ≥ 46% measured by conventional aggregometry. Both high MATHROMBIN(≥ 68 mm) and CYP2C19*2 allele carriage were independently associated with ADP-induced platelet aggregation (β coefficient: 8.3% and 12.0%, respectively). The combination of CYP2C19*2 allele carriage and high MATHROMBIN increased the predictive value for the risk of HPR (odds ratio: 13.89; 95% confidence interval: 3.41 to 55.56; p < 0.001). MACE occurred in 25 patients (12.7%). HPR and high MATHROMBIN were both associated with MACE (hazard ratio: 3.09 and 2.24, respectively), and patients with both HPR and high MATHROMBIN showed an increased risk for MACE (adjusted hazard ratio: 5.56; 95% confidence interval: 1.85 to 16.67; p = 0.002). In conclusion, this is the first study to demonstrate that high platelet-fibrin clot strength is an independent determinant of HPR in PCI-treated patients. Combining the measurements of platelet aggregation and platelet-fibrin clot strength may enhance post-PCI risk stratification and deserves further study.