Published online Oct 26, 2018. doi: 10.4330/wjc.v10.i10.165
Peer-review started: March 28, 2018
First decision: May 2, 2018
Revised: May 21, 2018
Accepted: August 26, 2018
Article in press: August 27, 2018
Published online: October 26, 2018
To statistically examine the released clinical trials and meta-analyses of polymeric bioresorbable scaffolds resuming the main accomplishments in the field with a translation to the routine clinical practice.
The statistical power in clinical trials such as ABSORB Japan, ABSORB China, EVERBIO II, AIDA, and few meta-analyses by the post hoc odds ratio-based sample size calculation, and the patterns of artery remodeling published in papers from ABSORB A and B trials were evaluated.
The phenomenal admiration from the first ABSORB studies in 2006-2013 was replaced by the tremendous disappointment in 2014-2017 due to reported relatively higher rates of target lesion failure (a mean prevalence of 9.16%) and device thrombosis (2.38%) in randomized controlled trials. Otherwise, bioresorbable vascular scaffold (BVS) performs as well as the metallic drug-eluting stent (DES) with a trend toward some benefits for cardiac mortality [risk ratio (RR), 0.58-0.94, P > 0.05]. The underpowered design was confirmed for some studies such as ABSORB Japan, ABSORB China, EVERBIO II, AIDA trials, and meta-analyses of Polimeni, Collet, and Mahmoud with some unintentional bias (judged by the asymmetrical Funnel plot). Scaffold thrombosis rates with Absorb BRS were comparable with DES performed with a so-called strategy of the BVS implantation with optimized pre-dilation (P), sizing (S) and post-dilation (P) (PSP) implantation (RR, PSP vs no PSP 0.37) achieving 0.35 per 100 patient-years, which is comparable to the RR 0.49 with bare-metal stents and the RR 1.06 with everolimus DES. Both ABSORB II and ABSORB III trials were powered enough for a five-year follow-up, but the results were not entirely conclusive due to the mostly non-significant fashion of data. The powered meta-analyses were built mostly on statistically poor findings.
The misunderstanding of the pathology of transient scaffolding drives the failures of the clinical trials. More bench studies of the vascular response are required. Several next-generation BVS including multifunctional electronic scaffold grant cardiology with a huge promise to make BVS technology great again.
Core tip: The high rates of target lesion failure and device thrombosis in randomized controlled trials caused confusion in the international interventional community with a decline of the technology in routine practice. The provided statistical analysis confirms the underpowered design of some clinical studies and meta-analyses of bioresorbable scaffolds. The misunderstanding of the pathobiology of the transient scaffolding drives the failures of the clinical trials. More bench studies of the vascular response are required to verify the leading mechanism of the device failure. Several next-generation scaffolds including multifunctional electronic scaffold grant cardiology with a huge promise to make this technology great again.