Apical Left Ventriculotomy is Safe in Infants and Young Children Requiring Cardiac Surgery

Introduction

In 1967, an article coauthored by Robert Gross contained the comment “It is obviously with some temerity that the systemic ventricle is deliberately incised . . .,” a philosophy that pervades and persists in cardiac surgery to this day. ¹ The assumption is based upon previous associations between incisions in the left (or systemic) ventricle with increased mortality and morbidity, particularly in infants. ^2,3 In order to determine whether this assumption is still true in the current era of early cardiac surgery, we reviewed our recent experience with left ventriculotomy in neonates and infants.

Materials and Methods

Between August 2007 and September 2010, five patients underwent repair of a cardiac lesion via a left ventriculotomy approach by the senior surgeon (C.J.K.-C.); a retrospective review of these records constitutes the basis for this study. The diagnoses were multiple ventricular septal defects, which included three large apical muscular ventricular septal defects, one massive left ventricular rhabdomyoma, and a left ventricular apical aneurysm of undetermined etiology. For the multiple ventricular septal defect patients, the mean age was 11 ± 3 months, with mean weight of 7 ± 2 kilograms. The patient with a rhabdomyoma was a critically unstable 5-day-old neonate weighing 2.6 kilograms. In this neonate, the ventricular mass originated from the base of the posterior mitral valve leaflet and occupied the entire ventricular cavity resulting in a tenuous prostaglandin-dependant circulation (Figure 1). The last patient was a 2-year-old male weighing 15 kilograms with a large functionally important left ventricular apical aneurysm in whom the presumptive diagnosis was an embolism to the mid-portion of the left anterior descending coronary artery (Figure 2).

OPEN IN VIEWER

Figure 1.

Echocardiogram of a neonate with a left ventricular mass.

OPEN IN VIEWER

Figure 2.

Cineangiogram of left ventricular apical aneurysm.

Echocardiograms were obtained postoperatively (ie, at time of hospital discharge) and then again at most recent follow-up, and left ventricular ejection fraction was recorded, forming the primary outcome measure of the analysis. Other end points were (1) intensive care unit length of stay, (2) hospital length of stay, (3) postoperative inotrope requirement, (4) postoperative arrhythmias, and (5) mitral valve function. The study was approved by the University of Tennessee Health Science Center Institutional Review Board.

Surgical Technique

All surgeries were done on cardiopulmonary bypass with moderate hypothermia and cold cardioplegic cardiac arrest. A 1 centimeter longitudinal apical left ventriculotomy is made parallel to, but several millimeters away from, the left anterior descending artery, creating a “fish-mouth” opening at the apex of the left ventricle (Figure 3). An important technical point is that in order to avoid injury to the papillary muscles, it is best to not vent the left heart during the time the apical incision is made but rather have the LV cavity filled with cardioplegia solution at the time of the incision. This allows the left ventricle to remain somewhat full, and the papillary muscles spread away from the ventricular septum and the incision. Following the repair, the ventriculotomy is closed primarily in two layers.

OPEN IN VIEWER

Figure 3.

Surgical approach to apical ventricular septal defect.

Results

There was no perioperative mortality. Although the left ventricular ejection fractions were slightly lower than their preoperative values, all remained greater than 50%. Results are enumerated below and in Table 1.

OPEN IN VIEWER

Table 1.

Results of Left Ventriculotomy

	Multiple VSD Patients (n = 3) (mean ± SD)	LV Aneurysm	Rhabdomyoma
Age	11 ± 3 months	2 years	5 days
Weight	7 ± 2 kg	15 kg	2.6 kg
Postop LVEF	61 ± 8 %	54%	58%
Follow-up LVEF		60%	53%
Extubated ≤48 hours	3/3	Yes	No
Hospital LOS	9 ± 7 days	5 days	18 days
ICU LOS	4 ± 1 days	2 days	7 days
Arrhythmias	0	PVC’s	0
Inotropes	Dopamine (n = 2) 3 mcg/kg/min	None	Epinephrine 0.05 mcg/kg/min

Abbreviations: VSD, ventricular septal defect; LV, left ventricle; LVEF, left ventricular ejection fraction; LOS, length of stay; SD, standard deviation; ICU, intensive care unit; PVC, premature ventricular contraction.

For the multiple ventricular septal defect patients, mean early postoperative ejection fraction was 61%. All three ventricular septal defect patients were extubated within 24 to 48 hours. Mean intensive care unit length of stay was 4 ± 1 days, with mean hospital length of stay 9 ±7 days. A prophylactic dopamine infusion at 3 mcg/kg per min was maintained for 24 hours in two patients. No patients experienced postoperative arrhythmias, and all had normal cardiac function at last echocardiogram.

In the patient with a ventricular aneurysm, early postoperative ejection fraction was 54%. The patient was extubated within 4 hours and remained in the intensive care unit for 2 days and in the hospital for 5 days. There was no inotrope requirement, and no perioperative arrhythmia requiring treatment other than electrolyte supplementation. At 11 months of follow-up, the ejection fraction is 60%, with normal mitral valve function.

The neonate with a rhabdomyoma had an early postoperative ejection fraction of 58%. Prior to surgery the left ventricle could not maintain a cardiac output, and, in addition, there was moderate mitral regurgitation related to the ventricular mass interfering with mitral valve function. Postoperatively, the patient remained in the intensive care unit for 7 days, and 18 days overall in the hospital, mostly related to feeding issues. At 12 months of follow-up, the ejection fraction is 53%, with no more than physiologic mitral valve regurgitation.

Comment

A left ventriculotomy has been a controversial surgical approach for intracardiac surgery for decades, despite early experimental evidence that it could be well tolerated. ⁴ Much of the assumption of increased mortality comes from earlier eras, when patients were older, and at greater risk of death from sequelae such as advanced pulmonary vascular disease from long-standing ventricular septal defects, but even recently, left ventriculotomies were identified as independent risk factors for morbidity. ^5,6 In recent years, however, the reevaluation of the utility of a left ventricular approach has begun, as in a study from the group at the University of Michigan, in which a left ventriculotomy approach for multiple ventricular septal defects was associated with preservation of ejection frcation, including in neonates. ⁷

As mentioned in the “Surgical Technique” section, the precise anatomic location and orientation of the ventriculotomy has great impact on the results. In a canine experimental model, Waldhausen et al determined that longitudinal left ventriculotomies cause less disruption to the coronary vasculature, less injury to papillary muscles, and better preservation of ventricular function with smaller areas of ischemia compared to transverse incisions. ⁸ This experimental work was corroborated and refined by DiBernardo et al, in 1998, who demonstrated in animal models that apical placement of the incision had a less detrimental effect on stroke volume and left ventricular ejection fraction than longitudinal incisions in the ventricular free wall, based upon analysis of the various axes of left ventricular contraction. ⁹

While the bulk of work on feasibility of left ventriculotomies, especially in children, has focused on cases of multiple ventricular septal defects, ¹⁰ it is often necessary in other congenital or complex lesions in all age groups. ¹¹ The Mayo Clinic group described an “apical myectomy” approach for patients with hypertrophic cardiomyopathy which we applied to our 2-year-old child with mid-cavitary obliterative hypertrophy and a large dyskinetic apical aneurysm. ¹²

Our present study adds to the growing body of evidence suggesting that in appropriately selected cases, an apical left ventricular approach is not associated with significant mortality or important morbidity in the short term. By echocardiography, the left ventricular function appears to be preserved (53%-58%), and the postoperative course (time to extubation, intensive care unit length of stay, inotrope requirement) seems to be in line with current trends and standards of care. ¹³ No child spent more than 7 days in the intensive care unit, with 4 days being the average for the multiple ventricular septal defect patients. Four of our five patients were extubated within 48 hours postoperatively. The limitations of this analysis are, obviously, the small number of subjects, and the need for longer term follow-up. Nonetheless, we feel that our experience adds to a body of information supporting the contention that this technique can be safely applied in appropriately selected patients, with reasonable expectation of short-term outcomes which are satisfactory. As therapies continue to evolve, and sometimes give way to “hybrid” techniques, the surgeon should always consider an apical left ventriculotomy as a suitable approach to a variety of congenital cardiac lesions. ¹⁴