Editorial: What is transposition of the great arteries?

Revival and modification of the Mustard operation

OBJECTIVE

The neonatal arterial switch operation is currently the procedure of choice for patients with transposition of the great arteries. However, a large number of patients present too late for the arterial switch operation and are best managed with the atrial switch operation.

METHODS

We have used the Mustard operation in its original form or following a new modification designed to enhance the atrial functions and filling of the left ventricle in an attempt to improve long-term results.

RESULTS

Between July 2013 and November 2018, a total of 101 patients underwent the Mustard operation, 86 with the new modification. The median age at operation was 16 months (6 months to 27 years). A total of 75 patients (74.3%) were male. Median preoperative oxygen saturation was 71%. There were no early deaths and there were 3 late deaths during a median follow-up period of 24.2 months (all in patients with large ventricular septal defect and established pulmonary vascular disease). At the latest follow-up, all patients were in stable sinus rhythm. There were no baffle leaks. Seven patients had asymptomatic narrowing of the superior baffle, and 1 patient required balloon dilatation. Follow-up is 100% complete and includes computed tomography and magnetic resonance imaging at regular intervals (75 patients to date). Computerized analysis of representative subsets showed enhanced rate and pattern of filling of the left ventricle in the modified operation compared with the classic operation.

CONCLUSIONS

The use of the Mustard operation, particularly the modified technique should play an important role in treating late-presenting patients with transposition of the great arteries. Improving the pattern of filling of the left ventricle could enhance the long-term results of the Mustard operation.

Conal anatomy in 119 patients with d-loop transposition of the great arteries and ventricular septal defect: an echocardiographic and pathologic study

OBJECTIVES

We sought to study the range of conal morphology in transposition of the great arteries with ventricular septal defect and their embryologic and surgical implications.

BACKGROUND

Conal anatomy in transposition of the great arteries and ventricular septal defect is variable and might affect surgical repair.

METHODS

Conal anatomy was explored using two-dimensional echocardiography in 119 patients with transposition of the great arteries and a large ventricular septal defect who presented between 1984 and 1991. The influence of conal anatomy on surgical technique was determined by review of the operative reports. Specimens of transposition of the great arteries with unusual conal anatomy were selected from the Cardiac Registry for comparison with the echocardiograms.

RESULTS

One hundred five patients (88.2%) had subaortic conus only with no subpulmonary conus (Group 1). Subarterial conus was present bilaterally in eight patients (6.7%) (Group 2). Four patients (3.4%) had only subpulmonary conus with no (or minimal) subaortic conus (Group 3). Among these four patients, the aorta was posterior to the pulmonary artery in one patient, side by side relative to the pulmonary artery in two patients and slightly anterior in the fourth patient. Subarterial conus was absent bilaterally in two patients (1.7%) (Group 4); the aorta was slightly posterior in one and side by side with the pulmonary artery in the other.

CONCLUSIONS

This variability of conal anatomy in transposition of the great arteries with ventricular septal defect implies four mechanisms by which transposition can occur. The conal anatomy appeared to affect surgical repair in Groups 1 and 2 insofar as it influenced ventricular outflow tract obstruction. In Groups 3 and 4, an arterial switch operation was performed in four of the six patients. The posterior location of the aorta obviated the need for the Lecompte maneuver in two of these four patients. In the remaining two cases in Groups 3 and 4, the condition was repaired by directing the left ventricular outflow across the ventricular septal defect to the aorta using a patch, with or without placement of a conduit from the right ventricle to the pulmonary artery.

Morphogenetic considerations on congenital malformations of the outflow tract. Part 2: Complete transposition of the great arteries and double outlet right ventricle

On the basis of our recent embryologic work concerning the separation process of the outflow tract, our study of the morphology of specimens from the Leiden Collection of malformed hearts, and in conjunction with our review of the literature, we have reconsidered the morphogenesis of complete transposition and double outlet right ventricle. In complete transposition, a mirror-image arrangement of the columns of the aorto-pulmonary septum could explain the discordant ventriculo-arterial connexion and might thus play a role in its development. Dedicating a cardinal role to the aorto-pulmonary septum in the morphogenesis of complete transposition does not, however, seem justified. Double outlet right ventricle is not an embryologic entity. From the stance of the embryologist, we prefer to consider double outlet right ventricle in terms of a feature that may occur in specimens related to hearts with either a concordant ventriculo-arterial connexion (such as tetralogy of Fallot, or the so-called Eisenmenger ventricular septal defect), or a discordant ventriculo-arterial connexion (complete transposition).

Atypical d-transposition of the great arteries: anterior pulmonary trunk

Clinical, angiocardiographic and necropsy data in a case of atypical d-transposition of the great arteries with an anterior pulmonary trunk are described. The unusual arrangement of the great arteries and the presence of bilateral coni were demonstrated with angiocardiography and confirmed on pathologic study.