Six-Month Evaluation of a Transcatheter Aortic Valve (Myval) in a Novel Ovine, Supra-Aortic Banding Model
29 Pages Posted: 1 Nov 2021 Last revised: 4 Nov 2021 Publication Status: Preprint
Abstract
BackgroundLong-term evaluation of transcatheter heart valves (THV) in the pre-clinical setting and clinical translation of outcomes was limited.AimWe evaluate biocompatibility and durability of a balloon expandable THV system (Myval, Meril Lifesciences) at 6-month follow-up in the novel ovine aortic banding model.MethodsA surgical ascending aortic banding model was created in 11 sheep. Two weeks later, 11 Myval THV systems (20 and 23 mm) were introduced and implanted via carotid approach for a 6 month follow-up. Transthoracic echocardiography was performed at 30, 90, and 180 days. Subsequently, the animals were sacrificed and the valves with surrounding tissue harvested for pathological and radiographic evaluation.ResultsAll valves were implanted successfully. There were 2 procedure-related deaths (18,1%). Two sheep died prematurely (18,1%), first on day 133 due to endocarditis and second on day 74 due to native aortic valve leaflet entrapment by prosthesis (18,1%). Total cumulative survival was 63,7%. At 6 months all valves that completed follow-up (n = 7) were functional with no significant regurgitation, calcification, thrombi, or vegetation. At terminal follow-up, mean pressure gradient was 21.9{plus minus}11 mm Hg, Vmax = 3.3{plus minus}1 m/s and ejection fraction of 53.3 {plus minus} 6%. In pathology, implant cusps were healed, covered with endothelialized and fibrocellular neointima, whereas the conduits were fully integrated without inflammatory reaction. There were no signs of thrombus or moderate to severe calcifications.ConclusionsIn this novel aortic banding model, surviving animals with Myval THV showed optimal deployment and good hemodynamic performance at 6 months and healing was complete.
Keywords: Aortic stenosis, TAVR, Pre-clinical research, Medical Innovation
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