A Novel Transcatheter Device to Treat Calcific Aortic Valve Stenosis: An Ex Vivo Study

Aortic valve stenosis (AVS) is the most common valvular disease in developed countries. Surgical or transcatheter bioprosthetic aortic valve (AV) replacement is the standard treatment for severe AVS. However, bioprostheses are prone to structural degeneration. Hence, in terms of lifetime management, there is a need for therapies that can postpone AV replacement. With the aim of fragmenting calcifications and restoring AV leaflets flexibility, a new transcatheter debridement device (TDD) exploiting ultrasound is under development. We performed an ex-vivo study on human hearts to quantify how TDD treatment affects stenotic AVs hemodynamic. Additionally, a qualitative histological analysis was performed to assess TDD's impact on AV leaflets.

Three human hearts affected by AVS were characterized pre- and post-treatment in an ex-vivo beating heart simulator. To replicate physiological flowrates, a pulsatile pump was connected to the left ventricle, while a systemic impedance simulator connected to the aortic root and a reservoir connected to the left atrium closed the hydraulic circuit. Transvalvular pressure drop (ΔPsys), backflow volume, and effective orifice area (EOA) were evaluated. For histological analysis, AV leaflets sections were stained with Haematoxylin/Eosin and AlizarineRedS to highlight calcifications.

The treatment induced a reduction in ΔPsys in all tested samples, improving EOA, but caused an increase in backflow volume. Moreover, histology suggested AV leaflets integrity.

The TDD procedure improved AV fluid-dynamics during systole in all tested samples, without evidence of damage to tissues. This suggests TDD could be a promising option to postpone AV replacement for patients with AVS.