Systematic review and meta-analysis of transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis

Background: Transcatheter aortic valve implantation (TAVI) has emerged as an acceptable treatment modality for patients with severe aortic stenosis who are deemed inoperable by conventional surgical aortic valve replacement (AVR). However, the role of TAVI in patients who are potential surgical candidates remains controversial. Methods: A systematic review was conducted using five electronic databases, identifying all relevant studies with comparative data on TAVI versus AVR. The primary endpoint was all-cause mortality. A number of periprocedural outcomes were also assessed according to the Valve Academic Research Consortium endpoint definitions. Results: Fourteen studies were quantitatively assessed and included for meta-analysis, including two randomized controlled trials and eleven observational studies. Results indicated no significant differences between TAVI and AVR in terms of all-cause and cardiovascular related mortality, stroke, myocardial infarction or acute renal failure. A subgroup analysis of randomized controlled trials identified a higher combined incidence of stroke or transient ischemic attacks in the TAVI group compared to the AVR group. TAVI was also found to be associated with a significantly higher incidence of vascular complications, permanent pacemaker requirement and moderate or severe aortic regurgitation. However, patients who underwent AVR were more likely to experience major bleeding. Both treatment modalities appeared to effectively reduce the transvalvular mean pressure gradient. Conclusions: The available data on TAVI versus AVR for patients at a higher surgical risk showed that major adverse outcomes such as mortality and stroke appeared to be similar between the two treatment modalities. Evidence on the outcomes of TAVI compared with AVR in the current literature is limited by inconsistent patient selection criteria, heterogeneous definitions of clinical endpoints and relatively short follow-up periods. The indications for TAVI should therefore be limited to inoperable surgical candidates until long-term data become available.