Novel epicardial off-pump device for mitral regurgitation: acute evaluation

First in human experience with an epicardial beating heart device for secondary mitral regurgitation

OBJECTIVE

We describe a novel, off-pump, epicardial implant that is intended to reshape both the mitral valve annulus and the left ventricle (LV) in those with secondary mitral regurgitation (MR).

METHODS

Five patients underwent an epicardial implant with the Mitral Touch device (Mitre Medical Corp, Morgan Hill, Calif), during concomitant off-pump coronary artery bypass for secondary MR. The median age was 71.2 years; 4 patients had severe MR and 1 moderate. Patients were followed for 1 year with transthoracic echocardiography and computed tomography. Safety, cardiac remodeling, and MR were assessed by an independent core laboratory.

RESULTS

One patient died within 30 days from nondevice-related organ failure and the remaining 4 survived through 1-year follow-up. Implant technical success was 100% and took an average of 52 minutes. Paired computed tomography showed mean left ventricular end-systolic volume remodeling at 1 and 12 months of -35% and -31%, respectively. They averaged left atrial end-systolic volume remodeling of -12% and -15% at 1 and 12 months. Right ventricular end-systolic volume changes of -19% and -8% and right atrial end-systolic volume remodeling of -5% and 1%, at the 1- and 12-month time points were noted. Regurgitant volume by transthoracic echocardiography decreased by 46% and 44% and the ejection fraction from 34.6% to 32.1% and 39.5%, at 1 and 12 months, respectively. There were no device-related complications reported to 1 year.

CONCLUSIONS

The Epicardial Mitral Touch System for Mitral Regurgitation (ENRAPT-MR) study demonstrates a first-in-man, off-pump, epicardial repair of secondary MR. Procedural safety and geometric correction of the mitral valve apparatus and LV was achieved. Further studies in the United States are underway.

Regurgitation Hemodynamics Alone Cause Mitral Valve Remodeling Characteristic of Clinical Disease States In Vitro

Mitral valve regurgitation is a challenging clinical condition that is frequent, highly varied, and poorly understood. While the causes of mitral regurgitation are multifactorial, how the hemodynamics of regurgitation impact valve tissue remodeling is an understudied phenomenon. We employed a pseudo-physiological flow loop capable of long-term organ culture to investigate the early progression of remodeling in living mitral valves placed in conditions resembling mitral valve prolapse (MVP) and functional mitral regurgitation (FMR). Valve geometry was altered to mimic the hemodynamics of controls (no changes from native geometry), MVP (5 mm displacement of papillary muscles towards the annulus), and FMR (5 mm apical, 5 mm lateral papillary muscle displacement, 65% larger annular area). Flow measurements ensured moderate regurgitant fraction for regurgitation groups. After 1-week culture, valve tissues underwent mechanical and compositional analysis. MVP conditioned tissues were less stiff, weaker, and had elevated collagen III and glycosaminoglycans. FMR conditioned tissues were stiffer, more brittle, less extensible, and had more collagen synthesis, remodeling, and crosslinking related enzymes and proteoglycans, including decorin, matrix metalloproteinase-1, and lysyl oxidase. These models replicate clinical findings of MVP (myxomatous remodeling) and FMR (fibrotic remodeling), indicating that valve cells remodel extracellular matrix in response to altered mechanical homeostasis resulting from disease hemodynamics.

Functional mitral regurgitation: modern concepts for ventricular geometry reshaping

Functional mitral valve regurgitation (MR), a condition affecting millions of primarily elderly patients worldwide, is associated with poor clinical outcomes. Functional MR has traditionally been considered a disorder of regional or global left ventricular (LV) remodeling secondary to myocardial disease, in which anatomically normal leaflets fail to coapt adequately. The primary mechanisms of MR are mitral annular dilatation and leaflet restriction secondary to LV remodeling. Although annuloplasty is commonly used to correct valve incompetence, the effects of altered ventricular mechanics on MR need to be specifically addressed. This review focuses on current concepts of geometric reconfiguration of the LV and mitral-ventricular apparatus to reduce MR.