A three-dimensional echocardiographic study on aortic-mitral coupling in transcatheter aortic valve replacement

Normal aortic valve (AV) and mitral valve (MV) function in a reciprocal interdependent fashion. We hypothesized that MV function would be affected by severe aortic stenosis (AS) and that it would remain altered after transcatheter AV replacement (TAVR). Using three-dimensional (3D) echocardiography, we studied aortic-mitral coupling in patients with severe AS undergoing TAVR and compared them with controls.

Three-dimensional transoesophageal echocardiography (Philips iE33) was performed on 43 patients: 27 with severe AS studied pre- and post-TAVR and 16 controls. A custom software tracked the aortic annulus (AoA) and mitral annulus (MA), allowing dynamic automated measurements of AoA and MA morphology, angle, and motion. The AS pre-TAVR patients had significantly reduced MA displacement, MA area, and maximum AoA area compared with the controls. Post-TAVR, MA displacement, MA area, and AoA area remained reduced. End-systolic AoA-MA angle was significantly wider in the AS patients compared with the controls and remained wider post-TAVR. Pre-TAVR, there was no difference in MA or AoA dynamics between patients with mild vs. moderate-to-severe MA calcium; Edwards-Sapien vs. a Medtronic CoreValve valve; normal vs. reduced left ventricular systolic function whereas post-TAVR, MA dynamics were significantly reduced in those with moderate-to-severe MA calcium.

This is the first study to demonstrate that AS can affect a secondary 'unaffected' valve, the MV, due to the calcification in the aortic-mitral fibrous continuity. TAVR does not result in recovery of MV structure. These changes have implications in the future TAVR valve development and the possible need for MV assessment pre- and post-TAVR.