Prospective, Multicenter, Randomized Controlled Clinical Study Evaluating the VitaFlow Liberty® Flex Transcatheter Aortic Valve Delivery System for the Treatment of Severe Aortic Stenosis Lesions

Summary

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.

Eligibility

Inclusion Criteria:

1. Diagnosis of severe aortic stenosis, defined as: echocardiographically confirmed peak aortic valve velocity ≥4.0 m/s, or mean aortic valve gradient ≥40 mmHg, or aortic valve area (AVA) ≤1.0 cm2 (or AVA index ≤0.6 cm2/m2);
2. Preoperative cardiac and great vessel CT angiography (CTA) with 3D reconstruction demonstrating an aortic-left ventricular angle \>60°, indicating potential challenges for arch crossing and valve crossing;
3. New York Heart Association (NYHA) functional class ≥II;
4. Voluntary participation in the study with signed informed consent.

Exclusion Criteria:

1. Known allergy or intolerance to components of the investigational or control devices (e.g., nitinol) or contrast agents;
2. Contraindication or known allergy to anticoagulant or antiplatelet therapy, rendering the patient unable to tolerate such treatment;
3. Known active infective endocarditis or other active infections;
4. Known severe vascular disease that would preclude safe prosthetic valve implantation;
5. Ascending aorta width ≥55mm;
6. Pre-procedural imaging shows aortic root anatomy unsuitable for transcatheter aortic valve implantation (including aortic root calcification that may affect proper valve expansion);
7. Pre-procedural echocardiography shows intracardiac mass, left ventricular or left atrial thrombus, or vegetation;
8. Acute myocardial infarction within 30 days prior to procedure (defined as Q-wave MI or non-Q-wave MI);
9. Concomitant severe mitral or tricuspid regurgitation;
10. Concomitant cardiogenic shock or hemodynamic instability requiring inotropic support, mechanical ventilation, or mechanical cardiac assistance;
11. Concomitant severe left ventricular dysfunction (defined as left ventricular ejection fraction LVEF\<20%);
12. Concomitant hematologic abnormalities defined as leukopenia (WBC count \<3×109/L), thrombocytopenia (platelet count \<30×109/L), history of bleeding diathesis or coagulopathy, or hypercoagulable state;
13. Female subjects known to be pregnant or breastfeeding;
14. Subjects currently participating in or planning to participate in other drug or device clinical studies within 12 months postoperatively; Any other condition that the investigator or heart team deems may hinder the subject's safe participation in the study.

Conditions2

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