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Randomized trial comparing 600- with 300-mg loading dose of clopidogrel in patients with non-ST elevation acute coronary syndrome undergoing percutaneous coronary intervention: results of the Platelet Responsiveness to Aspirin and Clopidogrel and Troponin Increment after Coronary intervention in Acute coronary Lesions (PRACTICAL) Trial.
Am Heart J. 2009 Jan;157(1):60.e1-9
Authors: Yong G, Rankin J, Ferguson L, Thom J, French J, Brieger D, Chew DP, Dick R, Eccleston D, Hockings B, Walters D, Whelan A, Eikelboom JW
BACKGROUND: There is uncertainty about the benefit of a higher loading dose (LD) of clopidogrel in patients with non-ST elevation acute coronary syndrome (NSTEACS) undergoing early percutaneous coronary intervention (PCI). METHODS: We compared the effects of a 600- versus a 300-mg LD of clopidogrel on inhibition of platelet aggregation, myonecrosis, and clinical outcomes in patients with NSTEACS undergoing an early invasive management strategy. Patients with NSTEACS (n = 256, mean age 63 years, 81.6% elevated troponin) without thienopyridine for at least 7 days were randomized to receive 600- or 300-mg LD of clopidogrel. Percutaneous coronary intervention was performed in 140 patients, with glycoprotein IIb/IIIa inhibitor use in 68.6%. Adenosine diphosphate (ADP)-induced platelet aggregation was measured by optical platelet aggregometry immediately before coronary angiography. RESULTS: Post-PCI myonecrosis was defined as a next-day troponin I greater than 5 times the upper limit of reference range and greater than baseline levels. Clopidogrel 600-mg LD compared with 300-mg LD was associated with significantly reduced ADP-induced platelet aggregation (49.7% vs 55.7% with ADP 20 micromol/L) but did not reduce post-PCI myonecrosis or adverse clinical outcomes to 6 months. There was no association between preprocedural platelet aggregation and outcome. CONCLUSIONS: These data confirm a modest incremental antiplatelet effect of a 600-mg clopidogrel LD compared with 300-mg LD but provide no support for a clinical benefit in patients with NSTEACS managed with an early invasive strategy including a high rate (69%) of glycoprotein IIb/IIIa inhibitor use during PCI.
PMID: 19081397 [PubMed - in process]