Effects of reconstructive surgery for left ventricular anterior aneurysm on ventriculoarterial coupling

Left-ventricular aneurysms: from disease to repair

Myocardial infarction may be complicated by the formation of a left-ventricular aneurysm that distorts the normal elliptical geometry of the ventricle to produce a dilated spherical ventricle with limited contractile and filling capacities. One of the consequences is congestive heart failure, which may be refractory to medical therapy and require surgical treatment. Surgical methods to restore the volume and shape of the left ventricle have evolved over the years. Nevertheless, although surgery for left-ventricular aneurysms has been performed for almost 50 years, the most appropriate approach is still controversial. This review gives an overview of the postinfarction left-ventricular aneurysm, tackling issues from the disease itself to surgical and other techniques of ventricular remodeling.

Mechanisms leading to reversible mechanical dysfunction in severe CAD: alternatives to myocardial stunning

Patients with severe chronic coronary artery disease (CAD) exhibit a highly altered myocardial pattern of perfusion, metabolism, and mechanical performance. In this context, the diagnosis of stunning remains elusive not only because of methodological and logistic considerations, but also because of the pathophysiological characteristics of the myocardium of these patients. In addition, a number of alternative pathophysiological mechanisms may act by mimicking the functional manifestations usually attributed to stunning. The present review describes three mechanisms that could theoretically lead to reversible mechanical dysfunction in these patients: myocardial wall stress, the tethering effect, and myocardial expression and release of auto- and paracrine agents. Attention is focused on the role of these mechanisms in scintigraphically “normal” regions (i.e., regions usually showing normal perfusion, glucose metabolism, and cellular integrity as assessed by nuclear imaging techniques), in which stunning is usually considered, but these mechanisms could also operate throughout the viable myocardium. We hypothesize that reversion of these three mechanisms could partially explain the unexpected functional benefit after reperfusion recently highlighted by high-spatial-resolution imaging techniques.

Left ventricular reconstruction benefits patients with dilated ischemic cardiomyopathy

BACKGROUND

Since the preoperative left ventricular end-systolic volume index (LVESVI) of greater than 100 mL/m2 was demonstrated to be an independent predictor of long-term mortality following isolated coronary artery bypass grafting (CABG), LV reconstruction (LVR) has been concomitantly performed in patients with a dilated LV due to ischemic cardiomyopathy.

METHODS

We retrospectively assessed the ability of preoperative and intraoperative variables to affect the actuarial survival in 48 patients with a preoperative LV ejection fraction (EF) of less than 0.30 and a preoperative LVESVI of greater than 100 mL/m2. Mean preoperative LVEF was 0.22 +/- 0.07, and preoperative LVESVI was 121 +/- 28 mL/m2. Coronary artery bypass grafting was performed in all patients. Mean number of grafted vessels was 2.8. The LVR was concomitantly performed in 20 patients and mitral valve plasty in 11. Preoperative and intraoperative variables were exposed to univariate and multivariate analyses.

RESULTS

There were 3 hospital deaths and 17 late deaths during the follow-up period. Causes of deaths were pump failure (9), myocardial infarction (2), ventricular arrhythmia (4), cerebral infarction (2), and cancer (2). Cox's proportional hazards model identified LVR and renal failure as independent factors, which affected the actuarial survival with odds ratios of 0.28 and 3.64 (p < 0.05). The 5-year actuarial survival (Kaplan-Meier) was significantly greater following LVR (90% +/- 11%) compared to isolated CABG (53% +/- 17%).

CONCLUSIONS

Left ventricular reconstruction contributed to improve the actuarial survival in patients with dilated ischemic cardiomyopathy, which could not be achieved by isolated CABG. The LVR can be an alternative to heart transplantation for the treatment of ischemic cardiomyopathy.

Ventricular energetics in endoventricular circular patch plasty for dyskinetic anterior left ventricular aneurysm

BACKGROUND

The endoventricular circular patch plasty (Dor procedure) applies to patients with a left ventricular dysfunction due to an ischemic dilated ventricle. In the present study, we analyzed left ventricular energetics in patients who underwent the Dor procedure.

METHODS

We measured left ventricular contractility (end-systolic elastance; Ees), afterload (effective arterial elastance; Ea), and efficiency (ventriculoarterial coupling; Ea/Ees, and the ratio of stroke work and pressure-volume area; SW/PVA) based on the cardiac catheterization data before and after the Dor procedure in 8 patients with a postinfarction dyskinetic anterior left ventricular aneurysm. Concomitant procedures included coronary artery bypass grafting in all patients, mitral valve repair in one patient, and cryoablation in one patient. End-systolic elastance (Ees) and Ea were approximated as follows: Ees = mean arterial pressure/minimal left ventricular volume, and Ea = maximal left ventricular pressure/(maximal left ventricular volume-minimal left ventricular volume), and thereafter Ea/Ees and SW/PVA were calculated. The left ventricular volume was normalized with the body surface area.

RESULTS

End-systolic elastance (Ees) increased after the Dor procedure (from 1.15 +/- 0.60 to 1.86 +/- 0.84 mm Hg x m2 x mL(-1), p < 0.01), thus resulting in an improvement in Ea/Ees and SW/PVA (from 2.94 +/- 1.11 to 1.64 +/- 0.49, p < 0.01, and from 0.426 +/- 0.110 to 0.559 +/- 0.082, p < 0.01, respectively), even though Ea did not substantially change (from 2.96 +/- 0.78 to 2.74 +/- 0.55 mm Hg x m2 x mL(-1), p = 0.4).

CONCLUSIONS

Left ventricular contractility and efficiency improves after the Dor procedure in patients with a dyskinetic anterior left ventricular aneurysm. However, afterload does not change. The use of appropriate afterload-reducing therapy thus plays an especially important role in the management of patients who undergo the Dor procedure.

Early results and operative considerations of endoventricular circular patch plasty for ischemic cardiomyopathy

Seven patients with ischemic cardiomyopathy who underwent elective endoventricular circular patch plasty (EVCPP) were included in this study. The mean age of the patients at the time of surgery was 63 years old. All seven patients had anterior left ventricular aneurysms following old myocardial infarction. Two patients were graded NYHA class II, 4 patients class III, and one patient class IV. EVCPP was performed under cardiac arrest with moderate hypothermia in five patients. The two most recent patients underwent EVCPP under on-pump beating and normothermia. Coronary artery bypass grafting was conducted in all cases and the mean number of grafts was 1.8, ranging from one to three. The mitral valve was replaced in one patient. One patient died of myonephrotic metabolic syndrome caused by ischemia of the lower limb. In the follow-up of six patients, the left ventricular end-diastolic volume index (LVEDI) decreased significantly from 128 +/- 31 mL/ m2 to 108 +/- 37 mL/m2. Left ventricular end-systolic volume index (LVESI) decreased in five patients. Left ventricular end-diastolic and end-systolic diameter remained unchanged after surgery. The left ventricular ejection fraction (LVEF) increased from 0.28 +/- 0.08 to 0.321 +/- 0.1. LVESI and LVEF did not improve in one patient with a large residual dyskinetic area at the distal LV septum. A residual dyskinetic area at the distal LV septum was observed in two of four patients who underwent EVCPP under cardiac arrest. This condition, however, was not detected in two patients who underwent EVCPP under on-pump beating conditions. In the follow-up study, the grade of NYHA functional classification improved in all six patients. In conclusion, EVCPP under on-pump beating is a realistic and effective procedure with which to complete ideal LV geometry and promote good results in patients with ischemic cardiomyopathy.

Surgical treatments for heart failure

The surgical options for CHF are a part of a larger paradigm shift in management. Viable and effective surgical options other than cardiac transplant and ventricular assist devices clearly exist and are applicable to a large portion of patients with CHF. These surgical therapies are of acceptable risk before decompensated CHF develops. The rapidly evolving therapies for altering LV remodeling, which underlies CHF progression, are an exciting area that may be joined in the future by molecular advances in myoblast transfer and gene therapy. These therapies are the basis of the discipline of CHF surgery within cardiovascular surgery.