Date Published: September 14, 2017
Publisher: Public Library of Science
Author(s): Shixuan Zhang, Peter L. Kolominsky-Rabas, Elena Cavarretta.
Transcatheter aortic valve implantation (TAVI) has been demonstrated to be an alternative treatment for severe aortic stenosis in patients considered as high surgical risk. Since its first human implantation by Cribier et al., TAVI has been shown to increase survival rate and quality of life for high surgical risks patients. The objective of this study is to provide an overview of TAVI registries and the reporting clinical outcomes based on the VARC-2 definitions. In addition, the comparability and adherence of VARC-2 reporting within the identified TAVI registries was reviewed.
A systematic review of TAVI registries reporting VARC-2 definitions has been performed in line with PRISMA guidelines in PubMed, ScienceDirect, Scopus databases and EMBASE. Based on VARC-2, patients’ characteristics and procedure characteristics, 30-day clinical outcomes, 1-year mortality and composited endpoints were extracted from each registry’s publications.
This review identified 466 studies that were potentially relevant, and 20 TAVI registries reported VARC-2 definitions involved in our present review. Of all 20 registries, an overall sample size of 12,583 patients was involved. The 30-day all-cause mortality ranged from 0 to 12.7%. From 20 registries, 14 registries reported the cardiovascular mortality at 30 days. 9 registries reported myocardial infarction (MI) rate based on VARC-2 definitions, and 7 registries reported peri-procedural MI rate (<72h). In our review, most of registries presented MI rates ranging from 0.5% to 2%. The majority of registries have reported complications such as bleeding, vascular complications and new pacemaker implantation. Since the introduction of VARC definitions from 2011, VARC and VARC-2 definitions are still not systematically used by all TAVI studies. These endpoint definitions warrant a concise and systemic analysis of outcome measures. Reporting TAVI-outcome uniformly makes study result comparison feasible. This definitely will increase patient safety, additionally to provide sufficient evidence to support decision makers like regulatory bodies, HTA agencies, payers.
This study identified 466 studies that were potentially relevant. Of all these studies, 37 originated from the PubMed (Medline) database, 274 from the Scopus database, 114 from the ScienceDirect and 41 were from the EMBASE. After removing duplicates, 323 abstracts have been reviewed independently by two researchers. According to the inclusion criteria and exclusion criteria, 197 studies from 74 registries were put into full text review. After full text reviewing, 69 studies from 20 registries were involved in the analysis in this study (Fig 1).
To our knowledge, this is the first systematic review analyzing clinical outcome reporting based on VARC-2 definitions. TAVI has become the fastest growing cardiac procedure since the introduction of coronary stents, with penetration rates of over 35% in countries such as Switzerland and Germany , where this rate has achieved to 52% In 2015 . Despite this growth, there was a lack of standardized reporting on clinical outcomes for patients undergoing TAVI before the introduction of VARC and VARC-2 definitions. As demonstrated and confirmed by Genereux et al. in a pooled analysis of 3,519 patients, VARC definitions already represent a new standard for consistency in reporting clinical outcomes for patients undergoing TAVI . The VARC-2 is an updated version of the original VARC. In the results section above, the authors summarized the registries reports using VARC-2 definitions based upon mortality as well as major complication categories. To address and support patients’ safety and procedural quality as demanded by regulatory bodies and HTA agencies, three main parts are needed to be taken into discussion: first of all, the authors provide the summary of the proportion use VARC-2 overall all TAVI registries; and investigate the trends of research in the field of TAVI since the introduction of VARC definitions; Secondly, the authors highlight important notices of reporting status for each complication, meanwhile, the authors compare the registry outcomes with meta-analysis of RCTs which use VARC and VARC-2 definitions , as well as the meta-analysis of studies based on VARC definitions . The authors also provide the influence factors description through comparison of single registry for each complication. In the last part, the author will summarize some aspects needed to be updated from VARC-2 definitions.
VARC and VARC-2 definitions are more and more widely used in clinical studies as well as in registry studies. However, since their introduction in 2011, VARC definitions are still not systematically reported in TAVI studies. These endpoint definitions warrant a concise and systemic analysis of outcome measures in high-risk patient populations. These standardized endpoint definitions make study result comparisons feasible, providing better insights by differentiating products and approaches, and thus increasing transparency for patients.