The Harvard Clinical Research Institute (HCRI) has announced results of the DAPT Study, a major international study that investigated the duration of dual antiplatelet therapy (DAPT, the combination of aspirin and a thienopyridine/antiplatelet medication to reduce the risk of blood clots) following coronary stent implantation. The continuation of dual antiplatelet therapy beyond one year resulted in significant benefits compared with aspirin alone, including reducing the rare but serious problem of stent thrombosis and preventing heart attack in other vessels. While longer-term dual antiplatelet therapy expectedly increased bleeding, severe and/or fatal bleeding was uncommon, and the difference between study groups was not statistically significant.
The DAPT Study assessed the benefits of 12 versus 30 months of dual antiplatelet therapy for preventing stent thrombosis and major adverse cardiovascular and cerebrovascular events (MACCE; composite of death, heart attack or stroke) in subjects undergoing percutaneous coronary intervention (PCI) with drug-eluting stent (DES) placement for the treatment of coronary artery lesions. While clotting inside the stent or in other blood vessels may occur after one year, the benefit of continuing treatment was unknown. The DAPT Study was performed as a public-private partnership in response to a request from the United States Food and Drug Administration (FDA) to the manufacturers of FDA-approved coronary stents to examine this important public health question in a broadly-inclusive and well-powered study.
Laura Mauri, M.D., M.Sc., principal investigator of the DAPT Study, interventional cardiologist at the Brigham and Women’s Hospital, Associate Professor of Medicine at Harvard Medical School and Chief Scientific Advisor for HCRI, presented these results in a late-breaking clinical trial session at the American Heart Association (AHA) Scientific Sessions 2014 in Chicago, and the results were published simultaneously in the New England Journal of Medicine1 . The findings from a secondary analysis of subjects who were treated with bare metal stents (BMS) were presented by Dean J. Kereiakes, M.D., the DAPT Study co-principal investigator, Medical Director of The Christ Hospital Heart and Vascular Center and The Carl and Edyth Lindner Center for Research and Education at The Christ Hospital, Cincinnati, Ohio. CT. Information regarding additional AHA presentations and publications related to the DAPT Study may be found at http://www.daptstudy.org/.
“The benefits of continuing dual antiplatelet therapy for 30 months were quite remarkable. The relative risk of a stent-related blood clot was reduced by 71%, compared with taking only aspirin after one year. The DAPT Study was the first and only study that was adequately powered to detect this benefit. Furthermore, the relative risk of heart attack was reduced by 53% by preventing these stent-related events, as well as by preventing events in vessels beyond the stented lesion,” said Dr. Mauri. “The study is a result of unprecedented collaboration amongst industry, government and academia, and valuable contributions from the investigators and patients.”
Concurrently Published Manuscripts Associated with the DAPT Study
1 Mauri L, Kereiakes DJ, Yeh RW, et al. Twelve or 30 Months of Dual Antiplatelet Therapy After Drug-eluting Stents. New England Journal of Medicine. Online ahead of print November 16, 2014.
2 Elmariah S, Mauri L, Doros G, et al. Extended Duration Dual Antiplatelet Therapy and Mortality: A Systematic Review and Meta-analysis. The Lancet. Online ahead of print November 16, 2014.
3 Stent Manufacturer-sponsored Studies Contributing to the DAPT Study, NCT00977938:
TAXUS Liberté Post Approval Study, Boston Scientific Corporation, NCT00997503
XIENCE V USA DAPT Cohort, Abbott, NCT01106534
EDUCATE, Medtronic, Inc., NCT01069003
CYPRESS, Cordis Corporation, NCT00954707
MacDougall Biomedical Communications, Inc.