Quantification of mitral annulus dynamic morphology in patients with mitral valve prolapse undergoing repair and annuloplasty during a 6-month follow-up

Abstract

Mitral valve (MV) repair is the preferred treatment for mitral regurgitation associated with organic MV prolapse (MVP). Our goals were to describe by transthoracic real-time 3D echocardiography (RT3D TTE) the pre-operative changes in mitral annulus (MA) dynamic morphology related to MVP, compared with a normal population, and to evaluate the differential long-term effects induced by annuloplasty, using either an incomplete flexible band or a complete semi-rigid ring. Forty-four patients (62 ± 11 years) with organic MVP and ejection fraction >55% were studied by RT3D TTE the day before MV repair, and 3 and 6 months after (23 patients received a complete rigid ring-CAR, 21 an incomplete flexible band-COS). An age-matched group of 20 normal subjects (57 ± 9 years) was studied as control. After initialization, the MA was tracked frame-by-frame in 3D, and several parameters computed. Differences in MVP vs. controls, vs. pre-surgery, and between rings were tested (P < 0.05). MVP showed enlarged MA resulting in greater area and height during the cardiac cycle, with reduced planarity compared with controls. Annuloplasty resulted in reduced MA area in both CAR and COS, with minimal area change, and planar shape (more evident in CAR than COS). The main factor affecting MA function after annuloplasty appears to be the undersizing of the MA dimensions, and not the choice of the ring. This methodology could represent the basis for further evaluation of implanted rings, to provide the surgeon with additional information to be used in the pre-surgical planning and ring selection.