3D echocardiography to evaluate ischemic mitral regurgitation in humans.

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

DESCRIPTION (provided by applicant): Ischemic mitral regurgitation (IMR) is a frequent complication of myocardial infarction that is associated with poor long-term survival. Irrespective of treatment, patients who develop IMR are at significantly increased risk for congestive heart failure (CHF) and have markedly worse prognoses following coronary revascularization. Results following mitral valve repair for IMR have been disappointing, and experienced centers report failure rates as high as 50% at 6 months post-repair. Recently reported imaging data suggests that pre- and post-repair IMR are associated with dilatation and flattening of the mitral valve annulus, preventing normal valve apposition and allowing regurgitant blood flow. The detailed basis for the failure of mitral valve repair and the effect of infarction-induced remodeling on mitral annular shape has been incompletely studied to date. Our aim is to assess the of impact of annuloplasty ring shape on human mitral valve mechanics and mitral valve repair durability in cases of IMR and show that the use of an annuloplasty ring that accurately reproduces the saddle shape of the native mitral annulus increases repair durability. To accomplish these goals we will utilize a novel technology: high-resolution, quantitative, 3-dimensiorial echocardiography for comprehensive imaging of the human mitral valve. This emerging technology will allow us to quantify the three geometric pathologies that contribute to the development of IMR: annular dilation, annular flattening, and leaflet tethering, and, therefore, predict which patients will benefit from mitral valve repair versus replacement. We will utilize real-time three-dimensional echocardiography (rt-3DE) to establish quantitative parameters of IMR. We aim to characterize the nature of annular remodeling in IMR with a spatial resolution not possible with previous imaging technology. In addition, we will assess the effects of ring annuloplasty shape on repair durability. IMR will be repaired in humans with either a standard fiat annuloplasty ring or a saddle ring that reflects native annular shape. For both valve groups, rt:-3DEparameters measured pre- and post-repair will be used to assess the degree of MR and characteristics of the mitral valve immediately, at 12 months, and at 24 months post-repair. The five-year survival for infarction-induced CHF approaches 50% despite best medical and surgical therapy, and the resultant strain on the healthcare system is staggering. The primary objective of this project is to develop a clinically relevant, noninvasive, powerful imaging modality for interrogating the mitral valve in cases of IMR, and to utilize this technique to delineate clinically effective, relevant surgical therapy.