High on-clopidogrel platelet reactivity predicts poor outcome after PCI
MedWire News: High on-clopidogrel platelet reactivity (HPR) is a strong predictor of cardiovascular (CV) death, myocardial infarction (MI), and stent thrombosis (ST) among patients who have received percutaneous coronary intervention (PCI), show the findings of a systematic review.
Previous studies have suggested a relationship between HPR and recurrent thrombotic events post-PCI, therefore Dániel Aradi (University of Pécs, Hungary) and colleagues carried out a systematic review and meta-analysis of studies published between January 2003 and February 2010 to summarize the available evidence.
They identified 20 observational studies, comprising 9187 patients receiving aspirin and clopidogrel therapy after PCI. All studies reported an intention-to-treat analysis on the clinical relevance of HPR, measured with an adenosine diphosphate (ADP)-specific platelet function assay.
The prevalence of HPR ranged from 6.1% to 79.9%, with an average of 32.3%. This variation was largely due to differences in platelet reactivity cutoff and the type of platelet function device used, says the team.
When results were pooled, HPR was associated with a significant 3.0-, 4.1-, and 4.9-fold increase in the rate of non-fatal MI, definite or probable ST, and composite ischemic events, respectively, compared with normal on-clopidogrel ADP reactivity.
In addition, patients with HPR had a 3.4-fold increase in CV mortality compared with those with normal reactivity.
Although there were large differences in the methodology, as well as in the definition of HPR, the predicted risk for CV death, MI, or ST did not differ significantly between the studies, observes the team.
"Whether HPR is a marker for adverse outcomes or a modifiable risk factor that can be diminished by more aggressive antiplatelet strategies remains to be established by ongoing, large-scale randomized trials," Aradi and co-authors conclude in the American Heart Journal.
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By Laura Dean