ABSORB II: Absorb BVS, Xience Yield Similar Outcomes at 2 Years

At 2 years, there are no significant differences with regard to clinical outcomes between the Absorb everolimus-eluting bioresorbable scaffold and the Xience everolimus-eluting stent, according to late-breaking results from the randomized ABSORB II study presented on Monday at TCT 2015.

Bernard Chevalier, MD, of the Institut Jacques Cartier, in Massy, France, cautioned that the trial was not powered for clinical outcomes and that 2-year data came from a non-prespecified interim analysis. The study’s primary endpoints of vasomotion and minimum lumen diameter at 3 years, he said, are not yet available.

Chevalier reported 2-year findings on 501 patients randomized 2:1 to receive Absorb BVS (n = 335) or Xience (n = 166 patients). The patient-oriented composite endpoint, MACE, device-oriented composite endpoint/target lesion failure and target vessel failure all were equivalent between the 2 devices.

To eliminate the role of periprocedural events, the investigators calculated a hazard ratio for patient-oriented composite endpoint from day 37 post-procedure to day 758 and again found no difference (HR 0.69; 95% CI 0.37-1.28; P = .2317). Additionally, no discrepancies were seen for MACE, device-oriented composite endpoint and TVF.

With regard to nonhierarchical events, there also were no significant differences. The death rate in the Absorb BVS group was 1.2% at 2 years, compared with 0.6% in the Xience group (P = .67). The MI rate in the Absorb BVS patients was 5.8% vs. 2.4% in Xience patients (P = .1). Definite/probable stent thrombosis occurred in 1.5% of Absorb BVS patients and in none of the Xience patients (P = .17). The rate of clinically indicated TLR was 2.7% with Absorb BVS and 1.8% with Xience (P = .76), while the rate of any revascularization was 5.8% and 9.1%, respectively (P = .17).

Postprocedural usage of antiplatelet medications was similar between the groups. In all, 92.2% of patients in both groups were taking aspirin at 2 years (P = .99) while 36.2% of Absorb BVS and 34.3% of Xience patients remained on DAPT at 2 years (P = .68).

Chevalier discussed the cases of very late definite stent thrombosis in Absorb BVS patients, one at 447 days and one at 602 days. Both patients were on aspirin alone at the time of the event, and possible causes included suboptimal expansion of the device, proximal stent malapposition, and incomplete lesion coverage at the device’s edges.

Jonathan Hill, MD, of Kings College Hospital, in London, United Kingdom, noted during a subsequent discussion that the Absorb BVS was implanted using IVUS in ABSORB II. This, he said, “may not represent how this device is put in, in the future.” The use of optical coherence tomography is more likely, he predicted.

Chevalier also noted that the investigators’ much longer experience with Xience compared with Absorb could have influenced the results. “The exploratory observations presented in this report are hypothesis-generating and need to be confirmed in larger randomized trials such as ABSORB III,” he advised.

Disclosures:

• Chevalier reports receiving consultant/honoraria fees from Abbott Vascular.