Prognostic Implication of Three-Dimensional Mitral Valve Tenting Geometry in Dilated Cardiomyopathy.

BACKGROUND AND AIM OF THE STUDY: Functional mitral regurgitation (FMR) is a clinically important complication of left ventricular (LV) dysfunction, occurring as a result of geometric deformity in the mitral valve (MV) complex. The study aim was to determine whether tenting parameters derived from real-time three-dimensional echocardiography (RT3DE) can predict the long-term prognosis for patients with dilated cardiomyopathy (DCM).

METHODS: Mitral valve tenting morphology, LV volume and function, and papillary muscle positions were monitored using transthoracic RT3DE in 75 subjects (66 with DCM, nine controls). The maximum tenting sites of the leaflet (maxTS) were also mapped from the reconstructed 3D images, to determine if the 3D tenting parameters correlated to long-term outcome.

RESULTS: Follow up information was collected from 62 patients with DCM over a mean period of 42 +/- 31 months. Cardiovascular events occurred in 30 patients (48%), including 13 cardiac deaths (21%). The patients were allocated to an Event group (n = 30) or a Non-event group (n = 32). The LV volumes were significantly larger and LV ejection fraction was lower in the Event group compared to the Non-event group. The 3D tenting volumes were significantly larger in the Event group than the Non- event group (p = 0.05). The maxTS were positioned mostly in the middle portion of the anterior mitral leaflet in the Non-event group (maxTS-mid AML), but in the Event group they were mostly found in the MV coaptation region of the leaflet (maxTS-coapt) (p <0.001). Patients with maxTS-coapt had a worse prognosis compared to those with maxTS-mid AML. On multivariate Cox regression analysis, maxTS was the strongest predictor of event-free survival.

CONCLUSION: The 3D tenting pattern, assessed with RT3DE, would be an important clinical parameter in predicting long-term prognosis in patients with DCM.