Background: Aortic annulus diameter is critical information for transcatheter aortic valve replacement (TAVR). Because aortic annulus is of an oval shape, three-dimensional measurements are indispensable. However, the geometric change of aortic annulus after TAVR is unclear. Thus, we tried to evaluate the shape and size of aortic annulus before and after TAVR by three-dimensional transesophageal echocardiography (3D-TEE).
Methods: In 27 patients (82.7±8.1 y/o) patients with severe aortic stenosis undergoing TAVR with SAPIEN XT prosthesis (23mm or 26mm), 3D-TEE was performed before and after replacement. Some patients were enrolled in PREVAIL JAPAN study. We performed the off-line analysis of aortic annulus geometry by the dedicated software (Q-LAB, Philips). We defined the aortic annulus as the plane formed by the 3 lowest points of aortic valve cusp and measured manually aortic annulus long diameter (DL), short diameter (DS) and Planimetry of the area (AAA) by multi-planar reconstruction images before replacement. Geometric mean diameter (DGM) was calculated as [2*√AAA/π]. Noncircularity of aortic annulus was calculated as eccentricity index (INECC) [1-(DS/DL) %]. After replacement, we also measured the external geometry of stent frame at the inflow level in the same way.
Results: Aortic valve area (0.56±0.12 vs. 1.36±0.20cm2, p<0.01) and mean pressure gradients (54±19 vs. 12±3mmHg, p<0.01) were improved after replacement. AAA (3.38±0.69 vs. 3.66±0.63cm2, p<0.01) and DGM (20.7±2.1 vs. 21.5±1.8mm, p<0.01) were significantly increased (0.86±0.76mm) and INECC was decreased (16.9±6.1 vs. 2.8±2.9%, p<0.01) after replacement.
Conclusions: The replaced prosthetic valve was larger than aortic annulus before TAVR and changed the shape into a circle. Aortic annulus should be three-dimensionally measured in view of the geometric change after TAVR.