Surgical approaches to dilated cardiomyopathy

Recurrent mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation

OBJECTIVES

We sought to characterize the temporal return of mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation; to identify its predictors, particularly with respect to annuloplasty type; and to determine whether annuloplasty type influences survival.

METHODS

From April 1985 through November 2002, 585 patients underwent annuloplasty alone for repair of functional ischemic mitral regurgitation, generally with concomitant coronary revascularization (95%). A flexible band (Cosgrove) was used in 68%, a rigid ring (Carpentier) in 21%, and bovine pericardial annuloplasty (Peri-Guard) in 11%. Six hundred seventy-eight postoperative echocardiograms were available in 422 patients to assess the time course of postoperative mitral regurgitation and its correlates. Most echocardiograms were performed early after the operation (median, 8 days); 17% were performed at 1 year or beyond.

RESULTS

During the first 6 months after repair, the proportion of patients with 0 or 1+ mitral regurgitation decreased from 71% to 41%, whereas the proportion with 3+ or 4+ regurgitation increased from 13% to 28% ( P < .0001); the regurgitation grade was stable thereafter. The temporal pattern of development of 3+ or 4+ regurgitation was similar for Cosgrove bands and Carpentier rings (25%) but substantially worse for Peri-Guard annuloplasties (66%). Small annuloplasty size did not influence postoperative regurgitation grade ( P = .2), although Cosgrove bands were used in most patients receiving 26- and 28-mm annuloplasties. Freedom from reoperation was 97% at 5 years. Annuloplasty type was not associated with survival.

CONCLUSIONS

Although initial mitral valve replacement would eliminate the risk of postoperative mitral regurgitation, this strategy has been associated with reduced survival. Therefore the development of additional techniques is necessary to achieve more secure repair of functional ischemic mitral regurgitation.

New surgical therapies for heart failure

A growing number of patients present with heart failure. Some of them may qualify for surgical correction of their cardiac condition. Since heart transplantation will always be available to only a small number of patients, several new surgical techniques have been developed for approval in heart failure patients. Classic interventions such as revascularization, valve repair, or valve replacement have been improved and modified to meet the need of heart failure patients. Several of these techniques are currently under investigation in large clinical trials. These trials will definitely have an impact on the development of surgical treatment of patients with heart failure.

Cell transplantation in non-ischemic dilated cardiomyopathy. A novel biological approach for ventricular restoration

OBJECTIVE

With a rising incidence, dilated cardiomyopathy (DCM) is regarded as a major health care concern. Although both medical therapy and novel surgical treatments have been applied to treat DCM, the effects of preventing left ventricular (LV) dilatation are limited, and the mortality rate associated with the disease remains high. Thus novel management strategies for improved treatment of DCM are awaited.

METHODS

Researchers have found that, in models of regional ventricular dysfunction, transplanted cells induced a profound biological phenomenon that restored contractile function and prevented ventricular dilatation. We have investigated muscle cell transplantation in hamsters with DCM, and have found that heart cells and smooth muscle cells survived in the host myocardium after transplantation, which suppressed LV dilatation and wall thinning, and preserved heart function. Our current studies are focusing on the clinical applicability of these encouraging early findings by evaluating the optimal cell types, the timing of transplantation, and cryopreservation as cell storage. Concurrently, we are investigating the influence of cell transplantation on myocardial remodeling in order to outline the mechanism of benefit afforded by donor cell engraftment. We believe that the timing of cell transplantation with respect to the progression of the underlying disease is critical in preventing ventricular thinning, dilation and preserving cardiac function.

CONCLUSIONS

This novel approach can be a clinically applicable biological therapy for patients with progressive DCM. More studies to uncover the specific molecular and cellular effects of cell transplantation on the host myocardium are necessary for future clinical application.