Comparing Transcatheter Aortic Valve Replacement (AVR) With Surgical AVR in Lower Risk Patients: A Comprehensive Meta-Analysis and Systematic Review

BACKGROUND: Transcutaneous aortic valve replacement (TAVR) is a novel percutaneous procedure for severe aortic stenosis and has been recently approved by Food and Drug Administration in lower risk patients. We performed the first ever meta-analysis and literature review of clinical trials comparing both 30-day and 1-year outcomes in lower risk patients undergoing TAVR vs. surgical aortic valve replacement (SAVR, having Society of Thoracic Surgeons score < 4% or equivalent). METHODS: Using predefined selection criteria as above, 68 articles were identified. Seven eligible articles were selected after extensive review. Primary effect outcomes were 30-day and 1-year all-cause mortality using risk ratio (RR) with significant P value of < 0.05. RESULTS: A total of 4,859 subjects were included. Risk of 30-day all-cause mortality was 40.1% less in TAVR group, RR 0.59 (95% confidence interval (CI): 0.38 - 0.92, P = 0.02) with no significant heterogeneity. Six studies except Schymik et al also reported 1-year risk. This was, however, not statistically significant with a 21% decrease in the TAVR group, RR 0.79 (95% CI: 0.57 - 1.09, P = 0.15). Six studies reported 30-day risk of secondary outcomes. The risk of 30-day stroke was 36% less in TAVR group, although this was not statistically significant, RR 0.64 (95% CI: 0.38 - 1.9, P = 0.10). The risk of acute kidney injury (AKI) stage 2 and above was 56% less in post-TAVR patients, RR 0.43 (95% CI: 0.35 - 0.54, P < 0.001) with no heterogeneity. For vascular complications, RR was high in TAVR group 4.62 (95% CI: 1.42-15.18, P = 0.01). Significant heterogeneity was demonstrated though (I(2) = 81). The risks for permanent pacemaker (PPM) were also higher in the TAVR group, RR 3.30 (95% CI: 2.04 - 5.33, P < 0.001) and significant heterogeneity was observed. After removing Thyregod et al and Partner 3 trial from the analysis, heterogeneity was removed, but the RR was still high 3.21 (95% CI: 2.54 - 4.068, P < 0.001). Post-operative incidence of endocarditis among TAVR patients was low but not statistically significant. The 30-day risk for infective endocarditis was RR 0.67 (95% CI: 0.13 - 3.48, P = 0.63). The 1-year risk was similarly low but not significant, RR 0.73 (95% CI: 0.28 - 1.92, P = 0.53). CONCLUSIONS: Among low risk patients, TAVR was found to be superior in short-term all-cause mortality and 1-year stroke, a result that was statistically significant for TAVR and close to significance for stroke. TAVR patients were also less likely to have post-operative bleeding and AKI stage 2 and beyond. Post-operative incidence of endocarditis among TAVR patients was low but not statistically significant. However, the rates of PPM and vascular complications are higher in TAVR patients. The results of TAVR in low risk population are thus extremely encouraging. However, the issue of long-term valve durability in this group needs further studies. Also, caution needs to be exercised while extending the indications to extremely young patients due to lack of enough studies.