TCT 2017: No advantage with extending dual antiplatelet therapy beyond six months in STEMI patients

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Resolute Onyx

The primary results from the DAPT-STEMI trial suggest that 12-month dual antiplatelet therapy (DAPT) is not superior to six-month DAPT in patients who have undergone percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). The study is one of several exploring shorter durations of DAPT after PCI.

Presenting the data at the 2017 Transcatheter Cardiovascular Therapeutics (TCT) meeting (29 October–2 November, Denver, USA), Elvin Kedhi (Isala Hartcentrum, Zwolle, the Netherlands) reported that second-generation drug-eluting stents “have consistently shown superior safety outcomes than their predecessors, even in STEMI patients” and this “questioned the need for a long duration of DAPT”. He added: “Whether a shorter DAPT duration is feasible in STEMI patients has not been previously studied.”

In DAPT STEMI, patients underwent PCI with a zotarolimus-eluting stent (Resolute Integrity, Medtronic) were prescribed DAPT for six months. At six months, patients who had not experienced an event (870 patients) were randomised to receive DAPT for another six months (437) or to receive aspirin monotherapy (433). The primary endpoint was a composite of all-cause mortality, myocardial infarction, any revascularisation, stroke, and TIMI major bleeding at 18 months.

At 18 months, there was not a significant difference between the 12-month DAPT and the six-month DAPT groups in the primary endpoint—6.6% vs. 4.8%, respectively—meaning the six-month DAPT was found to be non-inferior to 12-month DAPT (p for non-inferiority 0.004).There were also no significant differences in the secondary endpoint (a composite of all-cause death, myocardial infarction, stroke, stent thrombosis, or TIMI major bleeding at 15 and at 18 months at 12 months) between groups. There were also no differences between groups in the individual components of the primary endpoint.

“Six-month DAPT is non-inferior in regards to a combined safety, efficacy, and bleeding endpoint as compared to 12-month DAPT after primary PCI with a second-generation zotarolimus-eluting stent,” Kedhi concluded. He added: “This trial, for the first time, showed that, in the modern drug-eluting stent era, event-free STEMI patients do no benefit from a prolonged DAPT beyond six months as currently recommended.”

Similarly, the REDUCE trial—also presented at TCT—indicated that three-month DAPT after PCI with the Combo dual therapy stent (OrbusNeich) was non-inferior to 12-month DAPT in patients with acute coronary syndrome. In this study, the primary endpoint was a composite of all-cause mortality, myocardial infarction, stent thrombosis, stroke, target-vessel revascularisation, and bleeding at 12 months. Harry Suryapranata (Radboud University Medical Center, Nijmegen, The Netherlands), who presented REDCUCE at TCT, said: “The REDUCE trial shows that among acute coronary syndrome patients treated with a Combo stent, three months of DAPT is non-inferior to 12 months of DAPT. Therefore, this strategy could be considered if needed, even in acute coronary syndrome population.”

In their respective presentations, both Kedhi and Suryapranata stated further studies were needed to confirm the safety and efficacy of short-term DAPT in patients undergoing PCI with a new-generation drug-eluting stent. Speaking to Cardiovascular News, Kedhi commented that as DAPT-STEMI used a zotarolimus-eluting stent, it was “therefore the only stent that we can apply the results of DAPT-STEMI to”. He added: “While it is thinkable that other second-generation drug-eluting stents might offer similar benefits, this should still be proved by clinical trials.”

Additionally, at TCT, Kedhi reported that the Onyx One clinical study will compare the safety and efficacy of one-month DAPT after PCI with a zotarolimus-eluting stent (Resolute Onyx stent, Medtronic) with that after PCI with a drug-coated stent (BioFreedom, Biosensors) in patients at high-risk of bleeding. A previous study, LEADERS FREE, found that the BioFreedom stent was superior to a bare metal stent for the management of patients at high risk of bleeding. In this study, all patients received DAPT for one month after PCI.

Abbott is also exploring the safety and efficacy of a shorter duration of DAPT in patients at high risk of bleeding.  XIENCE Short DAPT, an open-label study, will compare with the safety and efficacy of three-month DAPT with that of 12-month DAPT following PCI with the company’s everolimus-eluting stent Xience.

At present, US and European guidelines advise that patients with acute coronary syndromes (including STEMI) should receive DAPT for at least 12 months.

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