Thirty months of DAPT linked to better outcomes in stable, unstable patients

SAN DIEGO — Patients randomly assigned 30 months of dual antiplatelet therapy experienced improvements in major CV outcomes at the consequence of increased bleeding, regardless of whether they were stented as a result of MI, according to results presented here at the American College of Cardiology Scientific Sessions.

Robert W. Yeh, MD, MSc, and colleagues aimed to evaluate the risks and benefits of 12 versus 30 months of DAPT among patients with and without MI undergoing coronary stent implantation following presentation.

Robert W. Yeh

The co-primary endpoints of the randomized, double blind, placebo-controlled trial included definite or probable stent thrombosis and major adverse CV and cerebrovascular events (MACCE, a composite of death, MI or stroke). GUSTO moderate or severe bleeding served as the primary safety outcome.

The researchers randomized 11,648 patients, of whom 9,961 underwent PCI with drug-eluting stents and 1,687 underwent it with bare-metal stents. Everolimus-eluting stents were most commonly used, according to Yeh. About two-thirds of the cohort was treated with clopidogrel, he added.

Approximately one-third of the cohort (30.7%; n=3,576) presented with ACS, while 8,072 were non-ACS patients.

“The DAPT study enrolled a heterogeneous group of patients,” Yeh, assistant professor of medicine at Harvard Medical School and the Massachusetts General Hospital Corrigan Minehan Heart Center, told Cardiology Today’s Intervention. “We know that patients with ACS have a higher risk for early and late ischemic events compared with those patients presenting with more stable disease, so we wanted to understand if the results that we found in the primary DAPT analysis were consistently observed in patients presenting with ACS compared with patients presenting with more stable disease.”

Study results

Ongoing thienopyridine treatment between 12 and 30 months in patients with MI was associated with a stent thrombosis rate of 0.5%, compared with a rate of 1.9% in those assigned placebo between 12 and 30 months (HR = 0.27; P < .001). Among patients without MI, 0.4% in the 30-month DAPT group had stent thrombosis, vs. 1.1% in the 12-month DAPT group (HR = 0.33; P < .001; P for interaction = .69).

The reduction in MACCE associated with 30-month DAPT was greater for those with MI than those without, according to the researchers. Among those with MI, the MACCE rate was 3.9% in the 30-month group and 6.8% in the 12-month group (HR = 0.56; P < .001). In those without MI, the MACCE rate was 4.4% in the 30-month group and 5.3% in the 12-month group (HR = 0.83; P = .08; P for interaction = .03).

Ongoing thienopyridine yielded a rate of subsequent MI of 5.2% among patients with MI, compared with a 2.2% rate for placebo (HR = 0.42; P < .001). In the non-MI group, the rate of MI was 3.5% in the 30-month group vs. 2.1% in the 12-month group (HR = 0.6; P < .001; P for interaction = .15).

MI occurred more frequently in the ACS population, according to Yeh. “The majority of MIs were not related to stent thrombosis,” he said.

Continued thienopyridine use was associated with increased bleeding among patients with MI (1.9% vs. 0.8%; P = .005), as well as for those with no MI (2.6% vs. 1.7%; P = .007; P for interaction = .21).

Lessons learned

Yeh added that there are some lessons to be learned from the DAPT findings. “One is that ACS patients are at higher risk for late ischemic events,” he said. “It turned out that they were at slightly lower risk for bleeding events. The benefits of extended-duration DAPT were accrued in both ACS and non-ACS patients. The absolute magnitude of the benefit was probably greater in the ACS patients. Nonetheless, the relative reductions in complications such as stent thrombosis and MI were really similar, actually, between the two populations.

“In both ACS and stable patients who have taken a year of DAPT after a stent procedure without bleeding, continuation of therapy should strongly be considered to reduce risks of stent thrombosis and MI,” Yeh told Cardiology Today’s Intervention. - by Rob Volansky and Erik Swain

References:

Yeh RW, et al. Abstract 406-06. Presented at: American College of Cardiology Scientific Sessions: March 14-16, 2015; San Diego.

Yeh RW, et al. J Am Coll Cardiol. 2015;doi:10.1016/j.jacc.2015.03.003.

Disclosure: Yeh reports serving on an advisory board for Abbott Vascular and consulting for Gilead Sciences and Merck.