Poor clopidogrel responsiveness linked to adverse PCI outcomes
MedWire News: Stable coronary artery disease (CAD) patients who respond poorly to clopidogrel are at increased risk for adverse clinical outcomes at 1 year, study results suggest.
Poor response to aspirin however, is not linked to adverse 1-year outcomes.
The findings of the study led by Gianluca Campo (Azienda Ospedaliera Universitaria Sant' Anna, Ferrara, Italy) also indicate that poor responders to either or both drugs have an increased risk for peri-percutaneous coronary intervention (PCI) myocardial infarction (MI), which is itself a further predictor of adverse long-term clinical outcomes.
The researchers used an assay to screen 826 patients with stable CAD undergoing PCI for aspirin and clopidogrel responsiveness. They then measured the combined primary outcome of death, MI, and stroke among the patients over a follow-up period of 1 year.
Overall, 278 and 548 patients were poor and full responders to aspirin and/or clopidogrel, respectively.
A glycoprotein (GP) IIb/IIIa inhibitor was taken by 47.5% of poor responders and 21.2% of full responders at the time of PCI.
Writing in the Journal of the American College of Cardiology, Campo and team report that over the follow-up period, 18 patients died, 80 had an MI, and two had a stroke.
The primary outcome occurred at a higher rate among poor aspirin and/or clopidogrel responders than among full responders, at 15.8% versus 8.6%, respectively (p=0.002).
Multivariate analysis showed that clopidogrel poor responders had a 15% higher risk for the primary outcome than full responders (p=0.01). Aspirin poor responders, however, were not at a significantly higher risk for the primary outcome.
The researchers also found that the occurrence of peri-procedural MI increased the risk for adverse 1-year primary outcome by 25%, irrespective of all other variables (p<0.01).
In addition, Campo and colleagues report that aspirin and/or clopidogrel poor responders taking a GP IIb/IIIa inhibitor had lower rates of peri-procedural MI than poor responders who were not taking the drug, at 21.2% and 34.7%, respectively (p=0.02).
This trend however, was not observed among aspirin and/or clopidogrel full responders.
Campo and colleagues conclude that although GP IIb/IIIa inhibitor therapy appears to remain a good option for minimizing peri-procedural MI risk in poor responders, "different strategies for maintenance therapy (eg, higher doses or switch to other drugs) should be tested to optimize the long-term outcome of poor responder patients."
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By Lauretta Ihonor