Long‐Term Outcomes of Transcatheter Aortic Valve Replacement in Low‐Flow Low‐Gradient Aortic Stenosis: A Reconstructed Time‐to‐Event and Multivariate Meta‐Analysis

BACKGROUND: There are uncertainties regarding long-term outcomes of low-flow, low-gradient (LFLG) severe aortic stenosis (AS) following transcatheter aortic valve replacement (TAVR). This study investigates long-term outcomes of TAVR for high-gradient (HG), classical LFLG, and paradoxical LFLG AS. METHODS: We systematically searched PubMed, Embase, Scopus, and Cochrane Library databases until January 2025 for studies comparing HG, classical LFLG, and paradoxical LFLG AS outcomes following TAVR. The primary outcome was all-cause mortality, analyzed using reconstructed individual patient data meta-analysis. Secondary outcomes included cardiovascular mortality, heart failure hospitalization, acute kidney injury, bleeding events, stroke, myocardial infarction, permanent pacemaker implantation, and echocardiographic outcomes, analyzed using multivariate meta-analysis. RESULTS: We included 19 observational studies comprising 20 493 patients who underwent TAVR for severe AS. Time-to-event meta-analysis indicated a higher risk of 5-year all-cause mortality in patients with classical and paradoxical LFLG AS compared with HG AS (hazard ratio [HR], 1.92 [95% CI, 1.62-2.27] and HR, 1.20 [95% CI, 1.07-1.34], respectively). Multivariate meta-analysis indicated an increased risk of cardiovascular mortality in patients with LFLG versus HG AS (classical LFLG HR, 1.94 [95% CI, 1.74-2.16]; paradoxical LFLG HR, 1.40 [95% CI, 1.25-1.57]). Classical and paradoxical LFLG AS were also associated with a higher risk of heart failure hospitalization (HR, 4.12 [95% CI, 2.16-7.83]; HR, 1.80 [95% CI, 1.14-2.85], respectively) compared with HG AS. CONCLUSIONS: Classical and paradoxical LFLG AS were associated with higher all-cause and cardiovascular mortality following TAVR compared with HG AS. Future studies are needed to determine strategies to improve outcomes following TAVR in patients with LFLG AS.