Primary arterial switch operation for transposition of the great arteries with intact ventricular septum in infants older than 21 days.

OBJECTIVES: The aim of this study was to assess the surgical outcome of the primary arterial switch operation (ASO) in infants 3 weeks to 2 months old.

BACKGROUND: The surgical management of transposition of the great arteries and intact ventricular septum (TGA/IVS) beyond 2 to 3 weeks of age is controversial. Concern that regression of the left ventricular (LV) myocardial mass will render the left ventricle incapable of coping with the acutely increased work of systemic perfusion has been considered a contraindication to a primary ASO.

METHODS: We used retrospective analysis of 37 patients 3 weeks to 2 months old and 156 patients <3 weeks old who underwent primary ASO with TGA/IVS to determine the surgical outcomes.

RESULTS: Between January 1990 and December 1996, primary ASO was performed in 37 patients 21 to 61 days old (late ASO group) and 156 patients <21 days old (early ASO group) with TGA/IVS. One (2.7%, 95% confidence interval [CI] 0.07% to 14.2%) of 37 patients and 13 (8.3%, 95% CI 4.5% to 13.8%) of 156 patients died. One late death occurred in each group. Mechanical LV support was required in 1 (2.7%, 95% CI 0.07% to 14.2%) of 37 late ASO and 6 (3.8%, 95% CI 1.4% to 8.2%) of 156 early ASO group patients postoperatively. Neither death nor the need for mechanical LV support in the late ASO group patients could be attributed to LV failure. In the late ASO group, age, LV geometry, LV mass index, LV posterior wall thickness index, LV volume index, LV mass/volume ratio, patent arterial duct or pattern of coronary anatomy did not predict death, duration of postoperative ventilation or inotropic support or time in intensive care. Moreover, there was no difference in duration of ventilation, duration of inotropic support or the time spent in intensive care in comparison to a random sample of 37 neonates from the early ASO group.

CONCLUSIONS: Primary ASO may be appropriate treatment for infants with TGA/IVS < or = 2 months old, regardless of preoperative echocardiographic variables. The upper age limit for which primary ASO is indicated in TGA/IVS is not yet defined.