Effect of oversizing and elliptical shape of aortic annulus on transcatheter valve hemodynamics: An in vitro study

Transcatheter aortic valve implantation (TAVI) is often performed in patients with non-circular aortic annulus and in oversizing (OS) conditions. The impact of elliptical annulus shape and the consequences of oversizing/underdeployment on the hemodynamic performance are still debated.

This in-vitro study aims to assess and compare the valve hemodynamic performances of the Edwards SAPIEN transcatheter heart valve (THV) in the different current conditions of use: important oversizing in small circular annuli and in elliptical annuli, moderate oversizing in circular and in elliptical annuli of various degrees of eccentricity.

A pulsed cardiovascular simulator was used. Edwards SAPIEN 23 and 26 (mm) were implanted in different circular and elliptical annuli of various sizes and eccentricity. Transvalvular mean pressure gradients (TPGm), effective orifice area (EOA) after implantation of Edwards SAPIEN THV were measured by Doppler-echocardiography and the performance index (PI=100 × EOA/Annulus Area) was calculated. Para and transvalvular regurgitation was assessed by color-Doppler and leakage volume was quantified by flowmeter measurement.

For a given aortic annulus area, EOAs after implantation of Edwards SAPIEN THV were generally larger and TPGms lower with elliptical annuli compared to circular annuli. The PI was higher (p=0.047) for elliptical (48 ± 3%) than for circular annuli (43 ± 5%). Paravalvular regurgitation occurred only in the case of the SAPIEN 26 implanted in the elliptical annulus with highest eccentricity.

The results of this in-vitro study suggest that the EOAs of Edwards SAPIEN are better in elliptical than in circular annuli. No transvalvular regurgitation occurred and only one paravalvular regurgitation was observed after implantation of SAPIEN 26 in the highly eccentric annulus.