Extremely Small 20-mm Versus Standard-Size Balloon-Expandable Transcatheter Heart Valves: Propensity-Matched Analysis From the OCEAN-TAVI Registry

Background: The 20-mm balloon-expandable transcatheter heart valve (THV) represents the smallest available option for transcatheter aortic valve replacement (TAVR). Its current underutilization stems from concerns regarding prosthesis-patient mismatch, durability, and potential adverse outcomes. Objectives: The purpose of this study was to compare the long-term outcomes between the 20-mm balloon-expandable THVs and standard-size balloon-expandable THVs. Methods: Patients who underwent transfemoral TAVR with SAPIEN THVs were sourced from the OCEAN-TAVI (Optimized Transcatheter Valvular Intervention) registry, an ongoing, multicenter cohort study that has enrolled over 7,000 TAVR patients in Japan. A 1:3 propensity-matched analysis, based on 24 baseline clinical and echocardiographic variables, was used to contrast the 20-mm with >20-mm balloon-expandable THVs. Results: Of 5,086 eligible patients, 284 (5.6%) received the 20-mm balloon-expandable THV. After propensity-matching, the 20-mm THV group (n = 276) and the >20-mm THV group (n = 828) demonstrated balanced baseline characteristics, with an absolute standardized difference <0.10. The average follow-up duration for patients who were alive was 955 ± 512 days, and the average time to death was 584 ± 543 days. The 20-mm group showed a higher frequency of prosthesis-patient mismatch (PPM) (moderate PPM: 29.2% vs 10.8%; severe PPM: 4.9% vs 1.5%; P < 0.001). Over a 5-year period, all-cause mortality and heart failure rehospitalization rates were comparable between the 2 groups (all-cause mortality: 34.2% vs 38.0%; HR: 1.01; 95% CI: 0.74-1.37; P = 0.970; heart failure rehospitalization: 15.2% vs 16.3%; HR: 0.81; 95% CI: 0.50-1.29; P = 0.371). Conclusions: This registry-based study suggests that the initially observed inferior forward hemodynamics associated with the 20-mm THV do not translate into heightened long-term mortality or heart failure rehospitalization risks.