The 5-year risk associated with the NeoVas bioresorbable scaffold (BRS) versus cobalt chromium (CoCr) everolimus-eluting stents (EES) is comparable in a new randomized trial, despite previous signs of greater hazard with the BRS. However, researchers on the 560-patient study — published Tuesday online in JACC: Cardiovascular Interventions — warned that “comparability or the potential signs of harm of NeoVas BRS should be investigated in appropriately sized randomized trials in the future.” The study was led by Kai Xu, MD, and Xiaozeng Wang, MD, both from the General Hospital of Northern Theater Command, China, and Guosheng Fu, MD, from the Sir Run Run Shaw Hospital, China. BRS were introduced as a way to tackle very late stent thrombosis, restenosis and neoatherosclerosis concerns associated with metallic drug eluting stents (DES), the researchers noted. The aim is to improve vessel wall recovery to normal physiological pulsatility and adaptive vascular responses after being absorbed. However, despite US Food and Drug Administration (FDA) approval for Abbott Vascular’s everolimus-eluting poly-l-lactic acid (PLLA)–based BRS based on 1-year results showing noninferiority to the fluoropolymer-based CoCr everolimus-eluting stent (EES) for target lesion failure (TLF), an increased risk of adverse clinical events were later observed 5 years post-percutaneous coronary intervention (PCI). Adverse effects including BRS-related device thrombosis and target vessel myocardial infarction (TVMI) led to Abbott’s withdrawal of the first-generation PLLA-based BRS from the market. “This experience demonstrates that long-term clinical follow-up is essential to determine whether a novel BRS has an acceptable rate of adverse clinical events compared with contemporary metallic DES,” the researchers wrote. Following positive early data from the NeoVas randomized trial, the current study therefore set out to assess the 5-year risk in the study for Lepu Medical’s NeoVas, a new PLLA-based BRS. The prospective, multicenter, single-blind trial randomized 560 coronary artery disease patients with non-complex lesions and a reference vessel diameter of 2.5 to 3.75 mm and lesion length ≤20 mm in a 1:1 fashion to either treatment with the NeoVas BRS (n = 278) or Abbot Vascular’s CoCEES, XIENCE (n = 282), and followed for 5 years. Optical coherence tomography (OCT) and fractional flow reserve were performed in a prespecified subgroup of 166 patients at 3-year follow-up, the researchers said, noting that the 5-year risk observed with Abbott’s first-gen PLLA BRS was limited to the first 3 years after implantation. The researchers noted that, at baseline, there were no significant differences in demographic or risk characteristics between the groups, while quantitative coronary angiographic measures and device diameters and lengths were also similar. The 5-year target lesion failure rate was 9.5% in the NeoVas group, and 7.2% in the CoCrEES group (hazard ratio [HR]: 1.33; 95% confidence interval [CI]: 0.74 to 2.38; P = 0.33). Device thrombosis at 5-years were also similar (1.5% vs 0.7%, respectively; HR: 2.05; 95% CI: 0.37 to 11.16; P = 0.45), as was fractional flow reserve both post-procedurally and at 3-years (0.89 ± 0.07 vs 0.90 ± 0.05, respectively; P = 0.11). In the 3-year optical CT subset, NeoVas was shown to be substantially absorbed (72.3% ± 13.2%). The researchers added that adverse event rates were also similar with the two devices, including target lesion failure-led all-cause death (4% in NeoVas BRS vs 3.2% in CoCr EES; p = 0.63) and cardiac death (1.8% vs 1.1%, respectively; p = 0.50), target vessel myocardial infarction (2.5% vs 1.8%, respectively; p = 0.54, and any revascularization (10.5% vs 11.1%, respectively; p = 0.83). Still, they said that larger confirmatory randomized trials are required. In an accompanying editorial, TUM University Hospital German Heart Center’s Salvatore Cassese, MD, PhD, and Michael Joner, MD — also from the German Centre for Cardiovascular Research, Germany — stressed that “significant concerns” remain about the use of novel BRS devices due to similarities with the previous generation, after its withdrawal. However, they stressed that “The current study may offer some hope.” “Drawing upon their experience with the current BRS platform, the investigators are encouraged to investigate further iterations and novel devices with improved mechanical features, applying the utmost scientific rigor, scrutiny, and transparency,” concluded the editorialists. Sources: Xu K, Fu G, Wang X, et al. 5-Year Outcomes With a Novel Coronary Sirolimus-Eluting Bioresorbable Scaffold: The NeoVas Randomized Trial. JACC Cardiovasc Interv; 18: 2107-2115. Joner M, Cassese S. Vascular Restoration With Bioresorbable Scaffolds: Epic Revolution or Pyrrhic Victory? JACC Cardiovasc Interv; 18: 2116-2119. Image Credit: Rasi – stock.adobe.com