Left ventricle is better suited as pulmonary ventricle in simple transposition with severe pulmonary hypertension

Background. The conventional treatment of transposition of great arteries with prepared left ventricle is an arterial switch operation. This, in our experience, does not hold for patients with transposition of great arteries with intact ventricular septum where the left ventricle continues to be prepared secondary to severe pulmonary arterial hypertension without an immediately reversible cause. Methods. Ten infants with D-transposition of the great arteries with essentially intact interventricular septum and severe pulmonary arterial hypertension underwent surgical treatment. Age ranged from 3 to 6 months (mean, 4.2 months). One of these patients had a large ductus with left to right shunting but the others had no intra- or extracardiac shunt to account for their pulmonary hypertension. All 10 had “prepared” left ventricles. The first 4 children underwent an arterial switch operation. Uneventful surgery was followed by prolonged ventilator dependence in all 4 with occurrence of severe pulmonary arterial hypertension every time weaning from ventilator was attempted. This was accompanied by metabolic acidosis and features of right heart failure. Only 1 patient with large ductus could be extubated and discharged from hospital. Subsequently, the other 6 infants underwent a Senning repair. Results. There was no early mortality. All patients were separated from mechanical ventilation within 48 hours of surgery without blood gas derangement or heart failure despite elevated pulmonary artery pressure in all. The child with the arterial switch operation has pulmonary artery pressure of 50% systemic 4 years following repair; although among the Senning group, 2 patients continue to have pulmonary artery pressure more than 60% of systemic and 4 have normal pulmonary artery pressure at a mean follow-up of 1 year. Conclusions. Atrial level repairs seem to perform better than arterial level repairs in children having TGA with persistent pulmonary artery hypertension without a correctable cause. Better tolerance of pulmonary arterial hypertension in this group is probably consequent to the superior ability of the left ventricle to tolerate a pressure load in the early postoperative period.