Experts debate long-term DAPT for patients with stents

BOSTON — While conceding that definitive research has yet to emerge, two experts at the Cardiometabolic Health Congress debated the merits of whether patients with stents should receive dual antiplatelet therapy for more than 1 year.

Ph. Gabriel Steg, MD, and Robert A. Harrington, MD, also agreed that the 1-year cut-point is an arbitrary one.

Ph. Gabriel Steg

Thrombosis risk does not end

The annual rate of stent thrombosis in patients with stents is 0.4% to 0.6% per year, and does not abate after 1 year, Steg, professor of cardiology at Paris Diderot University and director of the coronary care unit at Hospital Bichat-Claude Bernard, said during the debate. Further, many registry studies have shown that “at the time of DAPT discontinuation, there is actually an increase of stent thrombosis, particularly if that discontinuation was not planned. The risk is great in the first 30 days, particularly marked in the first week, following discontinuation,” he said.

While a meta-analysis of trials that examined short-term vs. long-term DAPT in patients with drug-eluting stents showed no difference in stent thrombosis and an increased risk for bleeding in patients taking long-term DAPT, “all of those trials are small and many of the trials were not designed to look at this,” Steg, a member of the Cardiology Today’s Intervention Editorial Board, said. “If you have an underpowered trial, showing no significant difference is absolutely not the same thing as showing that there is no difference. Absence of evidence is not evidence of absence.”

In addition, many CV events after PCI are not related to the stent or the culprit lesion, “and prolonged DAPT may be effective in preventing these events,” Steg said.

Robert A. Harringon

One registry study found that “there is benefit [from long-term DAPT] in reducing death, MI and stroke once you have the appropriate power,” Steg, said. “There is no question that continuing [DAPT] will increase bleeding. The question is, do we offset this with benefit on the true hard outcomes such as stent thrombosis, death, MI and stroke? I believe the answer will be yes.”

Short-term DAPT may be sufficient

Current guidelines recommend DAPT for up to 1 year because follow-up on studies of DAPT for patients with stents has been 1 year or less, Harrington, the Arthur L. Bloomfield professor of medicine and chairman of the department of medicine at Stanford University, said during the debate. In patients with bare-metal stents who do not have ACS, the guidelines recommend DAPT for up to 1 year, “but perhaps as low as 2 weeks might be sufficient,” he said.

The OPTIMIZE study of patients undergoing PCI with a zotarolimus-eluting stent (Endeavor, Medtronic) demonstrated no difference in the composite primary endpoint of all-cause death, MI, stroke and major bleeding between those assigned 3-month DAPT compared with those assigned 12-month DAPT (HR=1.03; 95% CI, 0.77=1.36; P=.002).

More data to come

Both Steg and Harrington agreed that the DAPT trial may provide a definitive answer on the optimal duration of DAPT in patients with stents. The trial includes more than 20,000 patients who were randomly assigned at 12 months after stent placement and DAPT prescription to DAPT or aspirin plus placebo, and followed for an additional 18 months.

Results from the DAPT trial, which was funded by the NIH, will be presented at the American Heart Association Scientific Sessions in November. – by Erik Swain

Editor’s note: The stances taken by each debater were for educational purposes and do not necessarily reflect their own views.

For more information:

Harrington RA and Steg PG. Expert Debates in Antithrombotic Therapy. Presented at: Cardiometabolic Health Congress; Oct. 22-25, 2014; Boston.

Disclosure: Harrington reports financial ties with Adverse Events, ApoPharma, AstraZeneca, Element Science, Gilead, Johnson & Johnson, Merck, Medtronic, MyoKardia, Regardo, Sanofi, The Medicines Company, TMC Pharma Services and WebMD. Steg reports financial ties with Amarin, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi Sankyo-Lilly, GlaxoSmithKline, Medtronic, Merck Sharp & Dohme, Novartis, Otsuka, Pfizer, Sanofi, Sevier, The Medicines Company and Vivus.