High post-clopidogrel platelet reactivity assessed by a point-of-care assay predicts long-term clinical outcomes in patients with ST-segment elevation myocardial infarction who underwent primary coronary stenting.

BACKGROUND: Recent studies have shown that post-clopidogrel high platelet reactivity (HPR), assessed by a point-of-care assay, is associated with a higher risk of adverse events after percutaneous coronary intervention (PCI). We assessed the clinical impact of HPR by the VerifyNow P2Y12 point-of-care assay in 181 patients with ST-segment elevation myocardial infarction (STEMI) who underwent primary PCI with drug-eluting stents (DES) at 3 hospitals.

METHODS: The primary endpoint of the study was the 12-month major adverse cardiovascular events (MACE), which comprised cardiovascular death, nonfatal MI and ischemic stroke. All patients received a single loading dose of 600 mg clopidogrel and 300 mg aspirin followed by a daily maintenance dose of 75 mg clopidogrel and 100mg aspirin.

RESULTS: A P2Y12 reaction unit (PRU) ≥ 282 (AUC 0.719, 95% CI 0.588-0.851, p=0.004, sensitivity 68.8%, specificity 73.8%) was the optimal cut-off value in predicting 12-month MACE by receiver operating characteristic curve analysis. Occurrence of MACE was significantly more frequent in patients with HPR (PRU ≥ 282) compared to patients without HPR (20.4% vs. 3.9%, HR 6.24, 95% CI 2.05-18.99, p=0.001). By multivariate analysis, HPR (HR 3.84, 95% CI 1.17-12.58, p=0.026) and elderly patients above 80 years of age (HR: 8.13, 95% CI 1.79-37.03, p=0.007) were found to be the significant predictors of 12-month MACE. The MACE-free survival rate was significantly lower in patients with HPR compared to patients without HPR (p<0.001).

CONCLUSION: HPR assessed by a point-of-care assay was able to predict 12-month MACE in patients with STEMI who underwent primary PCI with DES.