The Surgical Treatment of End-Stage Heart Failure

A bioenergetic assessment of mitral regurgitation: a new tool to assess severity?

Mitral regurgitation is frequently classified as mild, moderate or severe based on echocardiography. Patients with mild mitral regurgitation are usually managed medically. We hypothesise that mild mitral regurgitation as assessed volumetrically can in fact be severe when analysed from a bioenergetics point of view. The conservation of energy predicts that any regurgitant volume will require the heart to provide more work energy to support the circulation. Mitral regurgitation involves the left ventricle imparting potential energy, via blood pressure, and kinetic energy, via regurgitant velocity, to the regurgitant blood volume. This implies that regurgitant volume, regurgitant velocity, systolic blood pressure, heart rate, regurgitant orifice area and cardiac output are all important factors. We present limited data to demonstrate our hypothesis. A bioenergetic analysis of mitral regurgitation, may identify patients whose mitral regurgitation, assessed via echocardiography as mild, is actually clinically significant. In addition we identify the importance of blood pressure and heart rate control in patients with mitral regurgitation. The concept that a bit of mitral regurgitation in patients with poor left ventricles is a good thing, as it helps offload the left ventricle is from an engineering point fundamentally flawed.

Evaluation of nonscarred myocardial T1 value using contrast-enhanced look-locker cardiac MRI and its relationship to cardiac function in dilated cardiomyopathy: Comparison of 1.5 and 3.0 Tesla MRI

PURPOSE

To assess relationship between nonscarred myocardial T1 value measured using contrast-enhanced Look-Locker MRI and cardiac function in dilated cardiomyopathy (DCM) at 1.5 Tesla (T) and 3.0T MRI.

MATERIALS AND METHODS

Contrast-enhanced Look-Locker MRI was performed in 35 DCM patients. Nonscarred myocardial and blood T1 values were calculated from the signal intensity values and the delay time obtained on Look-Locker MRI. We assessed the correlation between the myocardial T1 value or myocardial T1 minus blood T1 value and cardiac function estimated using cine MRI (e.g., end-diastolic volume: EDV, left ventricular ejection fraction: LVEF) or brain natriuretic peptide (BNP).

RESULTS

With 1.5T MRI (n = 16), the myocardial T1 value correlated negatively with the EDV(r = -0.66) and end-systolic volume (ESV; r = -0.68), and positively with the LVEF (r = 0.51); the myocardial T1 minus blood T1 value correlated inversely with EDV (r = -0.70), ESV (r = -0.62), and brain natriuretic peptide (BNP; r = -0.56). With 3.0T MRI (n = 17), the myocardial T1 value correlated negatively with ESV (r = -0.44), septal thickness (r = -0.60), and BNP (r = -0.51), and positively with LVEF (r = 0.61); the myocardial T1 minus blood T1 value negatively correlated with BNP (r = -0.50) and positively with LVEF (r = 0.54).

CONCLUSION

The nonscarred myocardial T1 value measured with either 1.5T or 3.0T contrast-enhanced Look-Locker MRI is significantly related to cardiac dysfunction in DCM.

Mitral valve surgery in advanced heart failure

The appropriateness and timing of mitral valve surgery in patients with advanced heart failure and severe mitral regurgitation remains controversial. Recent surgical results provide evidence for beneficial effects on left ventricular remodeling and functional capacity. Given the absence of randomized trials comparing the outcomes of mitral valve surgery to medical therapy, however, clinical decision making regarding surgery for these fragile patients poses a dilemma to thoughtful clinicians. This paper reviews the pathophysiology of mitral regurgitation in heart failure and proposes an integrated approach to management.

[Advances in heart failure]

This article reports on the most significant developments in the field of heart failure in the past year. Principal innovations in the management of chronic heart failure are explained, including the most important features of new management models for patients with chronic heart failure and the main advances in drug therapy and in the use of and indications for cardiac devices in these patients. In addition, recent progress in the treatment of advanced heart failure, with particular emphasis on acute heart failure, is reviewed. Novel approaches to the surgical management of patients with heart failure, including new contributions in the field of the circulatory support, are also highlighted in this update.

Outcome of patients listed for heart transplantation after a failed surgical ventricular restoration procedure

Patients with end-stage ischemic cardiomyopathy (IHD) and left ventricular (LV) dilatation are increasingly treated by means of surgical ventricular restoration (SVR). In some patients, SVR can delay heart transplantation (HTX). We retrospectively analyzed our experience, trying to ascertain whether HTX after a failed SVR (fSVR) carried a greater mortality risk. Since 1985, we performed 742 HTX. Since June 1999, 133 IHD patients were listed for HTX. We assigned them to 3 groups: (A) not a redo (n=54); (B) redo after coronary artery bypass grafting (n=54); and (C) redo after fSVR (n=25). Respectively, 37, 33, and 12 patients underwent HTX with in-hospital mortality after HTX of 4/37 (10.8%), 12/33 (36.4%), and 2/12 (16.7%). Mortality on the list was 9/54 (16.7%), 11/54 (20.4%), and 7/25 (28.0%) respectively. Removal from the list occurred in 4, 5, and 2 patients, and 4, 5, and 4 patients are still awaiting HTX, respectively. In group C, the mean time from SVR to HTX list was 45.6+/-43.3 months, and list mortality occurred after 5.83+/-5.81 months. In-hospital mortality in both patients of group C was due to the occurrence of multisystem organ failure; 10/12 were extubated after 19.3+/-9.6 hours and discharged from the intensive care unit after 3.9+/-1.6 days. The recorded complications were: 3 acute renal failure, 1 pericardial effusion, and 2 episodes of acute rejection. Since only 5/25 patients with fSVR had undergone SVR at our institution, we cannot establish which patients were really eligible for HTX at the time of SVR. Our experience showed that patients listed for HTX displayed a high list mortality, but that HTX after a failed SVR did not seem to have a poorer outcome than HTX after previous conventional CABG.