Mitral valve motion after performing an edge-to-edge repair in an isolated swine heart

Objectives: Mitral valve motion after performing an edge-to-edge repair is a major concern, but it has not yet been observed directly. Mitral valve motion was assessed by using a high-speed digital video camera and microsonometric analysis in an isolated swine heart, and any changes in the mitral valve area or the development of mitral stenosis symptoms were evaluated. Methods: A temporary edge-to-edge repair model was created. The mitral valve motion was assessed by using a high-speed digital video camera, and the motion of the mitral annulus was measured by means of sonomicrometric analysis with or without performing edge-to-edge repair (n = 5). The left ventricular volumetric measurements were also measured with a conductance catheter. One cardiac cycle was divided into 4 phases: the mitral valve open phase, the isovolumic contraction phase, the aortic valve open phase, and the isovolumic relaxation phase. Results: The mitral valve was divided into 2 orifices by using the edge-to-edge technique, and the mitral valve area decreased by approximately 30%. The ratio of mitral valve open phase significantly decreased (31.9% ± 3.4% vs 41.4% ± 3.7%, P = .04). There were no significant differences in the diameter and the changes of anteroposterior dimensions of the mitral annulus. The stroke volume and the peak positive and negative dp/dt values showed no obvious change, but dv/dt values increased slightly without significance after removing the edge-to-edge suture (118 ± 25 vs 130 ± 17 mL/s, P = .14). Conclusions: The mitral valve area decreased slightly; however, edge-to-edge repair did not create symptomatic mitral stenosis and showed no adverse affects on cardiac function.