Multiple studies have shown a correlation between high on-treatment platelet reactivity (HPR) and ischemic complications after percutaneous coronary interventions (PCI); however, the role of platelet reactivity testing in order to adjust clopidogrel dose is debated. We sought to determine whether a strategy incorporating platelet reactivity testing with the Multiplate analyzer to tailor the dose of clopidogrel is superior to standard clopidogrel treatment after PCI. Between May 2008 and June 2009, 192 consecutive patients undergoing PCI were randomized to a tailored treatment strategy using the Multiplate analyzer or to uniform administration of 75 mg clopidogrel. In the tailored group, platelet function was assessed 24 h after clopidogrel loading, and patients with HPR (>46 U) received an additional 600 mg loading dose and 150 mg clopidogrel thereafter for one month. The primary endpoint was the composite of cardiac death, myocardial infarction, ischemic stroke or definite/probable stent thrombosis during six months. In the tailored group, a repeated loading dose of 600 mg clopidogrel significantly decreased platelet reactivity in patients with HPR (61.0 U [IQR: 52.5-71.5] vs. 21.5 U [15.8-30.5]; P < 0.0001) that remained unchanged during the maintenance phase on 150 mg clopidogrel (25.0 U [IQR: 19.8-27.0]; P = 0.20). The incidence of the primary endpoint was significantly higher in the standard clopidogrel group as compared to the Multiplate-tailored arm (5.3% vs. 0%, P = 0.03). In parallel, MACCE-free survival significantly improved in patients with Multiplate-tailored therapy (Kaplan-Meier log-rank: P = 0.02). Increasing the dose of clopidogrel according to the Multiplate assay may reduce ischemic complications in patients on clopidogrel after PCI.

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To shed light on the clinical significance of elevated CRP levels we performed a comparative analysis of the predictive values of both CRP and TnT in patients with unstable coronary artery disease for the occurrence of major cardiac events within 6 months. CRP and Troponin T were measured on admission in patients with acute coronary syndromes without ST segment elevation. Patients were treated according to a conservative management and the incidence of major cardiac events within 6 months was assessed. A total of 73 patients were included in the study. There were 27 major cardiac events (37%). An abnormal CRP (>4 mg/L) and an abnormal TnT (> 0.01 mg/L) were present in 36 patients (49.3%). The incidence of a major cardiac event was significantly higher among patients with CRP > 4 mg/L than in other patients (63.9 vs 10.8%), and this was evident both in patients with an elevated TnT (85.7 vs 20%) and in those without an elevated TnT (33.3 vs 4.5%). The sensitivity of a concentration of CRP > 4 mg/L for predicting a future ischaemic event was 85%, with a specifity of 72% and negative predictive value of 89%. For TnT > 0.01 mg/L the sensitivity was 77%, specifity 67% and negative predictive value 84%. The present study shows that both CRP, a non-specific acute phase reactant, and TnT, a cardiac specific marker of myocardial damage, are elevated early in a substantial number of patients with acute coronary syndromes. It shows that CRP and TnT are independent prognostic indicators of adverse ischaemic events.

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