According to a study published in JAMA, an additional 18 months of dual antiplatelet therapy (DAPT) after coronary stent replacement did not result in any significant differences in rates of stent thrombosis, adverse cardiac and cerebrovascular events or bleeding, compared to placebo.
Current guidelines recommended a minimum of 1 month of DAPT after base metal stent (BMS) placement following elective percutaneous coronary intervention and 6 to 12 months for drug-eluting stents (DES). Results from randomised trials show a reduction in stent thrombosis and non-stent-related heart with thienopyridine therapy beyond 12 months after DES placement. However, few trials have assessed the optimal duration of DAPT after BMS.
This study was conducted by Dean J. Kereiakes, M.D., of the Christ Hospital Heart and Vascular Center, Cincinnati, and Laura Mauri, M.D., M.Sc., of the Harvard Clinical Research Institute and Brigham and Women's Hospital, Boston, and colleagues. The research team randomly assigned 11,648 patients who received a bare metal stent (n = 1,687;) or drug eluting stent (n = 9,961), were treated with aspirin and who completed 12 months of DAPT without bleeding or ischaemic events to continued thienopyridine or placebo at months 12 through 30.
The findings show that patients treated with BMS who were randomised to continue thienopyridine vs placebo, rates of stent thrombosis were 0.5 percent vs 1.11 percent. Adverse cardiac and cerebrovascular events were 4.04 percent vs 4.69 percent; and rates of moderate/severe bleeding were 2.03 percent vs 0.90 percent, respectively. In both BMS and DES patients, stent thrombosis rates were 0.41 percent vs 1.32 percent; rates of MACCE were 4.29 percent vs 5.74 percent, and rates of moderate/severe bleeding were 2.45 percent vs 1.47 percent.
However, the study authors caution that it may be difficult to draw definitive conclusions because of the sample size. “The BMS subset may have been underpowered to identify such differences [in adverse events], and further trials are suggested.”
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