Shorter dual antiplatelet (DAPT) regimens for high-bleeding-risk (HBR) patients who underwent successful percutaneous coronary intervention (PCI) resulted in similar bleeding and thrombotic outcomes to the standard 12-month DAPT regimen in similar patients, according to study results presented Thursday at the TCT Connect virtual conference.
Furthermore, the shorter DAPT regimens reduced major bleeding in comparison with 12-month DAPT, the results show.
Roxana Mehran, MD, of Mount Sinai School of Medicine, New York, and Marco Valgimigli, MD, PhD, of Bern University Hospital, Switzerland, presented the results of three trials that are part of the XIENCE Short DAPT program.
XIENCE 90 enrolled 2,047 HBR patients across 106 U.S. sites to evaluate the safety of 3-month DAPT. The two XIENCE 28 trials enrolled 1,605 HBR patients at 111 international sites – 642 from 59 North American sites (XIENCE 28 USA) and 963 from 52 international sites (XIENCE 28 Global) to evaluate the safety of 1-month DAPT. All patients in all trials underwent PCI with the Xience everolimus-eluting stent (Abbott).
In XIENCE 90, patients were prescribed 3 months of DAPT after successful PCI. Those who were free from ischemic events and adhered to the DAPT regimen were eligible to be placed on aspirin monotherapy for 3 to 12 months. The primary endpoint was the composite rate of all-cause death or any myocardial infarction from 3 to 12 months in this so-called “3-month clear” population of 1,693 patients.
In XIENCE 28, patients were prescribed 28 days of DAPT after PCI. Patients who complied with the DAPT regimen and were event free (no myocardial infarction, repeat coronary revascularization, stroke or stent thrombosis) were placed on aspirin monotherapy. The primary endpoint was the composite of all-cause death or any myocardial infarction from 1 to 6 months in this so-called “1-month clear” population of 1,392 patients.
Patients in the XIENCE 90 and XIENCE 28 trials were compared to historical, comparable controls from the XIENCE V USA post-approval study (which took place from 2008 through 2011) using propensity-score-stratified analysis. Patients in the XIENCE V USA study underwent DAPT for 12 months.
Between 3 and 12 months, there was no difference between the XIENCE 90 and stratified XIENCE V USA patients in the incidence of the primary endpoint (5.4% vs. 5.4%; one-sided 97.5% upper confidence limit [UCL], 2.23%; noninferiority margin, 2.8%; p-noninferiority = 0.0063).
Between 1 and 6 months, there was no statistically significant difference between the XIENCE 28 and stratified XIENCE V USA patients in the rate of the primary endpoint (XIENCE 28, 3.5%, vs. XIENCE V USA, 4.3%; one-sided 97.5% UCL, 0.97%; noninferiority margin, 2.5%; p-noninferiority = 0.0005).
Turning to a major secondary endpoint, Bleeding Academic Research Consortium (BARC) 2-5 bleeding, the shorter DAPT strategies yielded numerically lower bleeding rates, but they did not reach superiority compared to the historical 12-month DAPT controls (BARC 2-5 bleeding rates, 3-12 months: XIENCE 90, 5.1%, vs. XIENCE V USA, 7.0%; p-superiority = 0.0687. BARC 2-5 bleeding rates, 1-6 months: XIENCE 28, 4.9%, vs. XIENCE V USA, 5.9%; p-superiority = 0.19).
Mehran also presented BARC 3-5 bleeding results, which she noted were not prespecified. These analyses did show superiority for the shorter DAPT strategies over 12-month DAPT (BARC 3-5 bleeding, 3-12 months: XIENCE 90, 2.2%, vs. XIENCE V USA, 6.3%; p-superiority < 0.0001. BARC 3-5 bleeding, 1-6 months: XIENCE 28, 2.2%, vs. XIENCE V USA, 4.5%; p-superiority = 0.0156).
The shorter DAPT regimens also did not appear to adversely affect stent thrombosis. Only 0.2% of XIENCE 90 patients experienced Academic Research Consortium (ARC) definite or probable stent thrombosis between 3 and 12 months, which was significantly below the 1.2% performance goal (two-sided 95% UCL, 0.63%; p<0.0001). Finally, the ARC rates of stent thrombosis between 1 and 6 months were roughly the same between the XIENCE 28 patients and stratified XIENCE V USA patients (0.3% vs. 0.3%).
The study received funding from Abbott.