Paravalvular Regurgitation In Tavi Of Edward Sapien Valve Is Not Related To Dyssymmetric Valve Expansion. A Multislice Computed Tomography Study

Background: Transcatheter aortic valve implantation (TAVI) is a novel technique for treatment of aortic stenosis in patients with high perioperative risk. It was previously shown that the self-expanding CoreValve, frequently presents dissymmetry, anatomical undersizing and incomplete apposition of struts. The aim of the present work was to evaluate symmetry and size of the balloon expanded Edwards Sapien valve (ES) by MSCT, aiming to evaluate whether central or paravalvular regurgitation may result from dissymmetric valve expansion. Methods: 24 patients underwent perioperative TEE and MSCT 1.7 (0.9 to 11.6) months after TAVI. Cross-sectional areas and smallest and largest diameters (D1, D2) were measured by MSCT at 3 determined levels: i.e. at the ventricular and aortic ends and in the middle of the stent. Stent area and diameters measured on implanted valves were indexed to the size of fully expanded stents measured by MSCT on unimplanted valves in vitro. Areas and dimensions of valves with significant (grade >1) vs. no or trivial paravalvular regurgitation were compared. Results: 11 patients had a 23 mm and 13 had a 26 mm ES prosthesis implanted. After TAVI, 16 patients had either no (n=10) or trivial (n=6) paravalvular regurgitation (group 1), while 8 patients had mild (n=3) to moderate (n=5) paravalvular regurgitation (group 2). By MSCT, the average minimal and maximal stent diameters were respectively 20.0±0.8 and 21.4±0.8 mm for 23 mm ES and 22.8±1.0 and 23.9±1.1mm for 26 mm valves. Average maximal to minimal stent diameter ratio was 1.04±0.04 for all valves. Only one patient had maximal to minimal valve diameter ratio > 1.1 indicative of dissymmetry. Both for the 23mm and 26 mm ES valves, stent areas were significantly larger at aortic (379.28±20.3 and 468.2±20.3 mm2 respectively) than at middle (351.7±14.9 and 438.7±26.4 mm2 respectively) or ventricular levels (338.6±18.5 and 415.6±31.0 mm2 respectively), p<0.001 by repeated measurements ANOVA. Measured area at aortic level in vivo was 95±18% of area measured in fully expanded unimplanted stents in vitro. There was no significant difference of stent area, minimal or maximal diameter or ratio of maximal to minimal diameter at any levels, among patients with trivial or less (group 1) or significant (group 2) aortic regurgitation. Conclusions: In our present series, the ES valve was found to expand homogeneously to 95% of predicted area with less than 4% dissymmetry. Paravalvular regurgitation was not related to dissymmetry nor incomplete expansion of stents.