This is a prospective, multicenter, randomized controlled clinical study designed to evaluate the real-world performance of the VitaFlow Liberty® Flex Transcatheter Aortic Valve Retrievable and Steerable Delivery System (Investigational Device) for treating severe aortic stenosis (AS) in challenging anatomies. The study will compare it against the VitaFlow Liberty® Retrievable Delivery System (Control Device), which lacks steerability.
Key Study Elements:
Objective: The primary objective is to assess the device's performance using the incidence of a composite endpoint before hospital discharge. This endpoint includes permanent pacemaker implantation (PPI), valve-in-valve (ViV) implantation, or moderate-to-severe paravalvular leakage (PVL).
Design: A prospective, multicenter RCT with 1:1 randomization (Experimental: VitaFlow Liberty® Flex vs. Control: VitaFlow Liberty®). Approximately 15 sites in China will participate. Subjects undergo follow-up at discharge, 30 days, and 1 year post-procedure. An independent data center handles management and analysis.
Population: Patients with severe AS (echo confirmed: peak velocity ≥4.0 m/s, mean gradient ≥40 mmHg, or AVA ≤1.0 cm²/AVAi ≤0.6 cm²/m²) AND preoperative CTA showing a challenging aortic-left ventricular angle \>60°. NYHA class ≥II is required.
Devices:
Investigational: VitaFlow Liberty® Flex (Retrievable \& Steerable Delivery System - Models DSRS21/24/27/30/A series; Loading Tools LT-S series).
Control: VitaFlow Liberty® (Retrievable Delivery System - Models DSR21/24/27/30; Loading Tools LT series).
Endpoints:
Primary: Composite of PPI, ViV, or moderate-to-severe PVL before discharge.
Secondary: Include individual components of the primary endpoint (ViV, PVL) immediately post-procedure, procedural success (VARC-3), technical assistance rates, valve retrievals, implantation depth, arch/valve crossing performance, valve hemodynamics (gradient, area, leak, LVEF), NYHA class, Major Adverse Cardiac and Cerebrovascular Events (MACCE - all-cause death, MI, stroke, reoperation), major vascular complications (at discharge/30 days).
Key Inclusion: Severe AS, challenging anatomy (aortic-LV angle \>60°), NYHA ≥II, informed consent.
Key Exclusions: Device/contrast allergies, anticoagulant intolerance, active infection, severe vascular disease prohibiting access, ascending aorta ≥55mm, unsuitable aortic root anatomy, intracardiac mass/thrombus, recent MI (\<30 days), severe concomitant mitral/tricuspid regurgitation, cardiogenic shock, severe LV dysfunction (LVEF\<20%), hematologic abnormalities, pregnancy/breastfeeding, participation in other device trials.
Visits: Screening (≤30d pre-op), Procedure (intra-op to 24h post-op), Discharge (≤7d post-op), 30d Follow-up (±7d), 12m Telephone FU (±1m).
Sample Size: Planned enrollment of 232 subjects (116 per group), calculated for superiority testing. Based on an expected composite endpoint rate of 21% for the Flex system vs. a historical rate of 38% for non-steerable systems (Superiority margin Δ1=0%, one-sided α=2.5%, Power=80%, accounting for 5% dropout).
Purpose: This study aims to demonstrate the superiority of the retrievable and steerable VitaFlow Liberty® Flex delivery system in reducing the composite rate of key adverse events (PPI, ViV, significant PVL) at discharge compared to the non-steerable system, specifically in patients with severe AS and anatomically challenging aortic-left ventricular angles.