DurAVR TM Biomimetic THV: EFS and FIH trial update

Published in Congress: Euro PCR 2024
Link: https://eurointervention.pcronline.com/doi/10.4244/EIJ-D-23-00282

Dr. Özkan Karaca

Introduction:
Trancatheter aortic valve replacement is a widely accepted treatment for patients with severe aortic stenosis (AS). Since its initial opening, there have been design improvements that have resulted in overall procedural versatility, ease of use, magnitude of results, reduction in residual paravalvular leak, and reduced need for a permanent pacemaker after implantation. The goal of restoring patients' hemodynamic performance and exercise ability to pre-existing conditions has led to the development of hemodynamics, diversity, and changes in existing valve design with technologies tailored to provide optimal acute and potential long-term benefits. Conventional bioprosthetic aortic valves consist of 3 separate pieces of flat tissue sewn together; this prevents the valve from opening fully, thereby causing enlargement of smaller orifice areas and is potentially associated with abnormal formation patterns. In contrast, the DurAVR transcatheter heart valve (THV) is produced by molding a single piece of tissue into the shape of the natural aortic valve, while also offering a larger orifice area and near-normal flow patterns.

Objective:
This study aimed to evaluate the safety and feasibility of the DurAVR THV, the first in its class biomimetic valve, in the treatment of symptomatic severe AS patients.

Methods:
This study is a first-in-human (FIH), prospective, nonrandomized, single-arm, single-center study. Patients with severe, symptomatic AS at high surgical risk and who were suitable for the DurAVR THV prosthesis were included in the study. Implant success, hemodynamic performance, and safety were evaluated by clinical, echocardiography, computed tomography (CT), and cardiac magnetic resonance imaging (CMR) at baseline, 30 days, 6 months and 1 year after the procedure. A total of 25 patients with severe, symptomatic AS at any surgical risk were screened for this study between November 2021-May 2022, and 13 patients were included in the study. The study used the balloon-expandable DurAVR THV, which surrounds a single piece of bovine pericardial tissue molded into a three-leaf valve to mimic the performance of a healthy native aortic valve. Patients were evaluated with medical, echocardiographic, CT and CMR evaluations, the Kansas City Cardiomyopathy Questionnaire (KCCQ), and the 6-minute walk test (6MWT) at baseline and 30 days, 6 months, and 1-year after the procedure. Primary performance endpoints were accurate positioning of a single DurAVR THV in the appropriate anatomical location and postoperative hemodynamic performance; safety endpoints at 30-day and 1-year follow-up were all-cause death, myocardial infarction, disabling stroke, and life-threatening bleeding.

Results:
13 patients (73.9±6.4 years old, 77% female) were included in the study. DurAVR THV was successfully implanted in all cases and no device-related complications were observed during the procedure. One access site complication, one permanent pacemaker implantation, and one case of moderate aortic regurgitation occurred. Apart from this, no death, stroke, bleeding, reintervention, or myocardial infarction was observed during follow-up. Although the mean annulus diameter was 22.95±1.09 mm, no degree of prosthesis-patient incompatibility was observed during the follow-up period (effective orifice area [EOA] 2.00±0.17 cm2 and mean pressure gradient [MPG] on the 30th day). Positive hemodynamic results were observed at 9.02±2.68 mmHg) and at 1 year (EOA 1.96±0.11 cm2, MPG 8.82±1.38 mmHg). New measures of valve performance derived from CMR demonstrated restoration of laminar flow consistent with the pre-disease state, with a mean coaptation length of 8.3±1.7 mm. CMR demonstrated restoration of aortic flow eccentricity and systolic flow reversal rate.

Comment:
This work; preliminary results from the FIH study with DurAVR THV demonstrated a good safety profile, with good hemodynamic performance and restoration of near-normal flow dynamics maintained at 1 year. DurAVR THV device has drawn a profile close to the natural valve structure, thanks to its one-piece valve structure that aims to increase the effective orifice opening, by showing hemodynamically close values ??and findings to normal flow parameters. This may have potential clinical benefits in reducing the risk of aortic dilatation and remodeling and ameliorating the potentially increased aortic stiffness seen after surgical aortic valve replacement. Additional studies are needed to investigate the prognostic significance of restoration of normal aortic flow on durability, myocardial recovery, and myocardial remodeling.