Absorb BVS Matches Xience V in Chinese Patients
The Absorb BVS performs comparably to the Xience V everolimus-eluting stent through 1 year in patients with coronary artery disease, according to results of the ABSORB China trial presented yesterday and published simultaneously in the Journal of the American College of Cardiology.
In the open-label trial, researchers led by Run-Lin Gao, MD, of Fu Wai Hospital, in Beijing, China, randomized 480 patients with up to 2 de novo lesions in different native coronary arteries to one of the two devices (both Abbott Vascular) at 24 sites in China. Average lesion length was approximately 14 mm. Patients were well matched for demographic, clinical and angiographic characteristics. Mean procedure duration was longer in the Absorb group (45.2 minutes vs 41 minutes; P = .05), but patients in the Absorb and Xience V groups had similarly high rates of device success (98% vs 99.6%; P = .22) and procedural success (97% vs 98.3%; P = .37).
At 1 year, in-segment late loss in the per-treatment-evaluable population (primary endpoint), defined as those patients who received only the study device without major prespecified protocol deviations, was 0.19 mm in the Absorb arm and 0.13 mm in the Xience V arm. The 0.06-mm difference met criteria for noninferiority (P = .01), and results were similar in the intention-to-treat population.
Additional quantitative coronary angiography at 1 year showed that patients who received the Absorb BVS had a smaller minimal lumen diameter (2.27 vs 2.5 mm; P < .0001), greater in-segment percent diameter stenosis (18.5% vs 11.3%; P < .0001), and increased in-stent lumen loss (0.23 vs 0.1; P = .0001). However, in-segment and in-stent restenosis was infrequent and comparable between groups.
The rate of target lesion failure at 1 year was 3.4% with Absorb and 4.2% with Xience V, a nonsignificant difference (HR 0.79; 95% CI 0.31-2.00; P = .62). Other clinical outcomes also did not differ between groups. Although the rate of all-cause death was significantly lower in the Absorb arm (0% vs 2.1%; P = .03), Gao said that disparity was likely due to chance. There was only 1 case of scaffold thrombosis, and no patients in the Xience V group developed stent thrombosis.
Longer-term data critical
A panel discussion after Gao’s presentation touched on the need for information on outcomes beyond 1 year to help operators decide between using a bioresorbable scaffold (BRS) over a current-generation DES. TCT Director Gregg W. Stone, MD, of New York-Presbyterian Hospital/Columbia University Medical Center, in New York, N.Y., noted that the added benefits of bioresorbable scaffold are expected to be seen after the scaffolds have completely disappeared. Potential long-term advantages include reductions in neoatherosclerosis, strut fracture and polymer reactions, the unjailing of jailed side branches and fewer ‘full metal jackets.’
“This is theoretical,” he said, “and it’s going to take us a good 5-plus years to get the long-term data… to see if the curves do separate as we’re hoping for.”
Nicolas M. Van Mieghem, MD, PhD, of Erasmus Medical Center, in Rotterdam, The Netherlands, said that lessons have been learned from the extensive European experience with Absorb BVS. One is that postdilatation is mandatory with all implants, he said, adding that he was surprised to see that the practice was used in only 63% of patients in the current trial. Another important lesson, he said, is that when operators are being introduced to bioresorbable scaffold technology, it is crucial to see how the device functions in real life. “And that means invasive imaging pre and post [procedure],” he said.
Finally, TCT Director Martin B. Leon, MD, also of New York-Presbyterian Hospital/Columbia University Medical Center, stressed that the interaction between operator and device is more intense when working with bioresorbable scaffold compared with DES, increasing the need for careful attention to preparation, postdilatation and imaging as the new technology is introduced into practice.
- The trial was sponsored by Abbott Vascular.
- Gao reports receiving a research grant from Abbott Vascular.
- Leon, Stone and Van Mieghem report relationships with multiple device companies.