Synergistic approaches in the surgical treatment of heart failure: complex solutions for complex problems

Cardiac remodeling and failure: from molecules to man (Part III)

Given the lack of a unified theory of heart failure, future research efforts will be required to unify and synthesize our current understanding of the multiple mechanisms that control remodeling in the failing heart. Matrix remodeling and the associated activation of inflammatory cytokines and MMPs have emerged as key pathways in the development of heart failure. As such, attempts to understand the integrated control of ECM homeostasis with the bioactivation of inflammatory cytokines may be of particular relevance to the development of effective anti-remodeling approaches. Notably, the implantation of isolated populations of cells in failing myocardium has a profound and consistent anti-remodeling effect that limits the progression to CHF. These observations were consistently identified in numerous studies using diverse experimental animal models and varied cell types. Accordingly, multicenter clinical trials are underway, and the preliminary data in patients with CHF are encouraging. Despite the enormous promise of cell transplantation to restore and regenerate failing myocardium, the mechanisms underlying these profound biological effects are not understood. An improved understanding of the myocardial response to cell implantation, particularly on parameters of matrix remodeling, may help unify our current understanding of the progression of heart failure and optimize the development of this technique for its evolving therapeutic use. The following review outlines recent advances in medical and surgical approaches to control the remodeling process that underlies the progression of heart failure.

Neurohormonal response to left ventricular reconstruction surgery in ischemic cardiomyopathy

OBJECTIVES

Activation of the neuroendocrine axis in congestive heart failure is of prognostic significance, and neurohumoral blocking therapy prolongs survival. The hypothesis that surgical reduction of left ventricular size and function decreases neuroendocrine activation is less established. We evaluated the neurohormonal response to left ventricular reconstruction surgery in ischemic cardiomyopathy.

METHODS

Norepinephrine, plasma renin activity, and angiotensin II were measured in 10 patients before and 12 months after left ventricular reconstruction. In an additional 5 patients, brain natriuretric peptide was measured before and 3 months postoperatively. Three-dimensional cardiovascular imaging was used to assess ejection fraction and left ventricular end-diastolic volume index.

RESULTS

Concurrent with improvements of New York Heart Association functional class (2.9 +/- 0.5 preoperatively vs 2.0 +/- 0.4 postoperatively, P <.001), ejection fraction (23.9% +/- 6.6% vs 36.2% +/- 6.2%, P <.01), and left ventricular end-diastolic volume index (140.8 +/- 33.8 mL/m(2) vs 90.6 +/- 18.3 mL/m(2), P <.01), considerable reductions were observed for median plasma profiles of norepinephrine (562.0 pg/mL vs 319.0 pg/mL, P <.05), plasma renin activity (5.75 microg/L/h vs 3.45 microg/L/h, P <.05), angiotensin II (41.0 ng/mL vs 23.0 ng/mL, P =.051), and brain natriuretric peptide (771.0 pg/mL vs 266.0 pg/mL, P <.05). The more plasma renin activity or angiotensin II decreased after left ventricular reconstruction, the higher was the increase in ejection fraction (R = -.745, P <.05 [plasma renin activity]; R = -.808, P <.05 [angiotensin II]).

CONCLUSIONS

Surgical improvements of ejection fraction and left ventricular end-diastolic volume index by left ventricular reconstruction were accompanied by improvement of both the neuroendocrine activity and the functional status in patients with congestive heart failure. Whether this favorable neurohormonal response is predictive of an improved survival requires further evaluation.

Contemporary outcomes of outpatients referred for cardiac transplantation evaluation to a tertiary heart failure center: impact of surgical alternatives

BACKGROUND

The growing epidemic of congestive heart failure in the setting of limited donor-organ availability has mandated continued development and increased utilization of medical and surgical alternatives to cardiac transplantation. We sought to assess current disposition and outcomes of patients recently referred for transplant evaluation to a single high-throughput tertiary referral center.

METHODS AND RESULTS

We performed a retrospective observational review of consecutive patients with advanced heart failure who were assessed initially in an outpatient setting by a heart failure cardiologist, with a view to transplant or nontransplant surgical alternatives between 1995 and 2000. Of 1174 consecutive referrals (mean age 55.1 [+/-12.7], 74% male), 588 (50%) were recommended for medical treatment (mean age 55.3 [+/-12.4], 72% male) and 200 (17%) for nontransplant surgery, principally coronary artery bypass grafting, mitral valve repair, infarct exclusion, partial left ventriculectomy, or combinations thereof (mean age 57.8 [+/-10.6], 76% male). A minority, 418 (36%), were initially listed for cardiac transplantation (mean age 53.5 [+/-13.9], 80% male). Of these, 74 (18% of listed) died waiting (34 on left ventricular assist device support), 45 were delisted (27 for improved clinical status), and 217 (18% of referred group) have been transplanted. The 3-year survival (Kaplan-Meier) was equivalent (82%) in the transplanted and nontransplant surgery groups (excluding partial left ventriculectomy patients).

CONCLUSION

In current clinical practice less than one fifth of transplant referrals are ultimately transplanted, reflecting both a limited donor supply and the application of alternative, nontransplant strategies. Medium-term survival in patients suitable for alternative surgical strategies equals that of cardiac transplantation.

Ventricular reconstruction surgery for congestive heart failure

The significant increase in the prevalence of heart failure in the United States has made this disease a major health problem. The continued shortage of donor organs has prevented heart transplantation from becoming an effective solution for the treatment of end-stage heart failure, and as a result, surgical treatments for heart failure have been reexamined. Surgical therapies represent the evolution of conventional operations, such as coronary artery bypass surgery, and the application of the more novel left ventricular (LV) reconstruction operations which address the geometry of the LV, the important component in the failing heart.

Tricuspid valve repair: durability and risk factors for failure

OBJECTIVES

To compare durability of tricuspid valve annuloplasty techniques, identify risk factors for repair failure, and characterize survival, reoperation, and functional class of surviving patients.

METHODS

From 1990 to 1999, 790 patients (mean age 65 +/- 12 years, 51% New York Heart Association functional class III or IV, and mean right ventricular systolic pressure 56 +/- 18 mm Hg) underwent tricuspid valve annuloplasty for functional regurgitation using 4 techniques: Carpentier-Edwards semi-rigid ring, Cosgrove-Edwards flexible band, De Vega procedure, and customized semicircular Peri-Guard annuloplasty. Of these patients, 89% had concomitant mitral valve surgery. A total of 2245 follow-up transthoracic echocardiograms were retrieved. Tricuspid regurgitation was analyzed, and risk factors for worsening regurgitation were identified, by multivariable ordinal longitudinal methods.

RESULTS

Tricuspid regurgitation 1 week after annuloplasty was 3+ or 4+ in 14% of patients. Regurgitation severity was stable across time with the Carpentier-Edwards ring (P =.7), increased slowly with the Cosgrove-Edwards band (P =.05), and rose more rapidly with the De Vega (P =.002) and Peri-Guard (P =.0009) procedures. Risk factors for worsening regurgitation included higher preoperative regurgitation grade, poor left ventricular function, permanent pacemaker, and repair type other than ring annuloplasty. Right ventricular systolic pressure, ring size, preoperative New York Heart Association functional class, and concomitant surgery were not risk factors. Tricuspid reoperation was rare (3% at 8 years), and hospital mortality after reoperation was 37%.

CONCLUSIONS

Tricuspid valve annuloplasty did not consistently eliminate functional regurgitation, and across time regurgitation increased importantly after Peri-Guard and De Vega annuloplasties. Therefore, these repair techniques should be abandoned, and transtricuspid pacing leads should be replaced with epicardial leads.

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.