Factors that preclude the use of a single-stage arterial switch reconstruction of dextrotransposition of the great vessels include

A. Age older than 6 weeks with a left ventricular pressure of less than 50% of systemic pressure.

D. Valvar pulmonic stenosis.

DISCUSSION: Single-stage arterial switch procedure for reconstruction of transposition of the great vessels, with or without associated VSD has become the standard of treatment in the majority of cardiac centers. Contraindications to arterial switch repair include fixed types of left ventricular outflow tract obstruction, including valvar pulmonic stenosis, which would render the systemic semilunar valve stenotic or incompetent. Anatomic abnormalities without stenosis, such as a bicuspid valve, however, are suitable for surgical correction. The location of VSD does not affect surgical outcome, and most VSDs can be approached adequately through the right atrium or the anterior great vessel. Most dynamic forms of left ventricular outflow tract obstruction are often relieved partially or completely by realignment of the ventricular septum with the hemodynamic changes following successful arterial switch repair. When, however, the left ventricle has not been prepared to sustain the pressure load of the systemic circulation by the decrease in pulmonary vascular resistance that occurs in the first few weeks of life and when the ventricular pressure is less than 50% of the systemic ventricular pressure, one-stage repair is contraindicated, and staged repair with pulmonary banding and shunt followed by arterial switch must be contemplated.