ADAPT-DES is the largest study ever to explore the overall treatment
implications of platelet reactivity on patient outcomes after
successful coronary drug-eluting stent implantation. Researchers
investigated the relationship between platelet reactivity during dual
therapy with aspirin and clopidogrel and clinical outcomes such as stent
thrombosis, major bleeding, and other adverse events.
The study enrolled 8,583 patients at 11 sites in the US and Germany
who underwent a percutaneous coronary intervention (PCI) with at least
one drug-eluting stent between January 7, 2008, and September 16, 2010.
Researchers assessed platelet reactivity with the VerifyNow Aspirin,
P2Y12, and IIb/IIIa tests. Patients were followed for one year to
determine the relationship between platelet reactivity and subsequent
events. At one year, stent thrombosis had occurred in 70 patients (0.8
percent), heart attack in 269 (3.1 percent), major bleeding in 531 (6.2
percent), and death in 161 (1.9 percent).
Platelet reactivity units (PRU), an index of platelet inhibition to
clopidogrel, were measured by the VerifyNow P2Y12 test. High platelet
reactivity, defined as a PRU of greater than 208, was present in 42.7
percent of patients. At one year, researchers found that high platelet
reactivity was significantly associated with stent thrombosis (1.3
percent vs. 0.5 percent) and heart attack (3.9 percent vs. 2.7 percent),
but was also found to be protective against major bleeding (5.6 percent
vs. 6.7 percent). High platelet reactivity was also associated with
one-year mortality (2.4 percent vs. 1.5 percent). However, because high
platelet reactivity is also associated with other patient risk factors
and baseline characteristics, multivariable modeling was also performed;
it showed no independent association between high platelet reactivity
"Results from the ADAPT-DES registry definitely demonstrate that
high platelet reactivity after implantation of drug-eluting stents is an
independent predictor of one-year stent thrombosis and heart attack,
but it is also protective against major bleeding, both of which impact
mortality," said lead investigator Gregg W. Stone, MD. Dr Stone is
professor of medicine at Columbia University College of Physicians and
Surgeons and Director of Cardiovascular Research and Education at the
Center for Interventional Vascular Therapy at NewYork-Presbyterian
Hospital/Columbia University Medical Center. Dr. Stone is also
co-director of the Medical Research and Education Division at the
Cardiovascular Research Foundation (CRF).
"Because of the counteracting effects of ischemia and bleeding,
platelet reactivity was not an independent predictor of one-year
mortality. Therefore, overcoming high platelet reactivity with more
potent antiplatelet agents is unlikely to improve survival unless the
beneficial effect of reducing stent thrombosis and heart attack can be
separated from the likely increase in bleeding that results from greater
platelet inhibition," said Dr. Stone.
Dr. Stone added: "Platelet reactivity on aspirin was unrelated to
stent thrombosis, heart attack, or death, but may be related to
bleeding. This raises questions as to the utility of aspirin in patients
treated with drug-eluting stents."
The ADAPT-DES trial was sponsored by CRF with research support from
Boston Scientific, Abbott Vascular, Medtronic, Cordis, Biosensors, The
Medicines Company, Daiichi Sankyo, Eli Lilly, Volcano, and Accumetrics.