Impact of Surgical and Transcatheter Aortic Valve Replacement in Low-Gradient Aortic Stenosis: A Meta-Analysis.

ABSTRACT Background Low-gradient (LG) severe aortic stenosis (AS) encompasses a wide variety of pathophysiology including classical low-flow, low-gradient (LF-LG), paradoxical LF-LG, and normal-flow, low-gradient (NF-LG) AS and uncertainty exists regarding the impact of aortic valve replacement (AVR) on each sub-class of LGAS. Objectives We aimed to assess the impact of AVR on survival in patients with each sub-class of LGAS, and to compare outcomes following surgical AVR (SAVR) and transcatheter AVR (TAVR). Methods PUBMED and EMBASE were queried through October 2020 to identify studies comparing survival of different management (SAVR, TAVR, and conservative) in LGAS. Pairwise meta-analysis comparing AVR versus conservative and network meta-analysis comparing SAVR versus TAVR versus conservative were performed. Results Thirty-two studies with a total of 6,515 patients and a median follow-up time of 24.2 (interquartile range 36.5) months were included. AVR was associated with a significant decrease in all-cause mortality in classical LF-LG (HR 0.42, 95%CI 0.36-0.48), paradoxical LF-LG (HR 0.41, 95%CI 0.29-0.57), and NF-LG (HR 0.41, 95%CI 0.27-0.62) compared to conservative management. SAVR and TAVR were each associated with a decrease in all-cause mortality in classical LF-LG (HR 0.46, 95%CI 0.38-0.55; HR 0.49, 95%CI 0.37-0.64, respectively), paradoxical LF-LG (HR 0.42, 95%CI 0.28-0.65; HR 0.42, 95%CI 0.25-0.72, respectively), and NF-LG (HR 0.40, 95%CI 0.21-0.77; HR 0.46, 95%CI 0.26-0.84, respectively) compared to conservative management. No significant difference was observed between SAVR and TAVR. Conclusion In all sub-class of LGAS, AVR was associated with a significant decrease in all-cause mortality regardless of surgical or transcatheter approach.