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Platelet reactivity after drug-eluting stent implantation predicted adverse outcomes
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High platelet reactivity on clopidogrel after drug-eluting stent implantation was an independent predictor of stent thrombosis and myocardial infarction at 1 year and also was protective against clinically relevant bleeding, according to study results published in The Lancet.
“The findings from this study emphasize the counter-balancing effects of hemorrhagic and ischemic complications after stent implantation, and suggest that safer drugs or tailored strategies for the use of more potent agents must be developed if the benefits of greater platelet inhibition in patients with cardiovascular disease are to be realized,” Gregg W. Stone, MD, director of cardiovascular research and education at the Center for Interventional Vascular Therapy at New York-Presbyterian Hospital/Columbia University Medical Center and co-director of the medical research and education division at Cardiovascular Research Foundation, and colleagues wrote.
Previous research on the association between platelet reactivity and stent thrombosis was inconclusive, according to background information in the study.
The prospective, multicenter registry study conducted by Stone and colleagues included 8,665 patients enrolled between January 2008 and September 2010. Participants included those who had been successfully treated with at least one drug-eluting stent and were adequately loaded with aspirin and clopidogrel, regardless of the number or complexity of lesions. All patients were treated with aspirin indefinitely and clopidogrel for at least 1 year.
The researchers assessed platelet reactivity after percutaneous coronary intervention using three point-of-care assays. Patients were analyzed at 30 days and 1 year after percutaneous coronary intervention and will be again after 2 years. High platelet reactivity on clopidogrel was defined as >208 P2Y12 reaction units (PRU). High platelet reactivity on aspirin was defined as >550 aspirin reaction units.
Definite or probable stent thrombosis served as the primary endpoint. Secondary endpoints included all-cause death, MI and clinically relevant bleeding.
After 1 year, stent thrombosis occurred in 0.8% of patients, MI occurred in 3.1% and clinically relevant bleeding developed in 6.2%. Death was reported in 1.9% of patients.
High platelet reactivity on clopidogrel was strongly associated with stent thrombosis (HR=2.49; 95% CI, 1.43-4.31) and MI (adjusted HR=1.42; 95% CI, 1.09-1.86). However, the researchers reported an inverse association with high platelet reactivity and bleeding (adjusted HR=0.73; 95% CI, 0.61-0.89). They observed no association between high platelet reactivity and death (HR=1.2; 95% CI, 0.85-1.7).
High platelet reactivity on aspirin was not significantly associated with stent thrombosis (adjusted HR=1.46; 95% CI, 0.58-3.64), MI or death, but there was an inverse association with bleeding (adjusted HR=0.65; 95% CI, 0.43-0.99).
Reference:
Stone GW. Lancet. 2013;382:614-623.
Disclosure:
The study was sponsored by the Cardiovascular Research Foundation with research support from Abbott Vascular, Accumetrics, Biosensors, Boston Scientific, Cordis, Daiichi Sankyo, Eli Lilly, Medtronic, The Medicines Company and Volcano. See the full study for a list of the researchers’ relevant financial disclosures.