Right ventricle failure and outcome of simple and complex arterial switch operations in neonates

To analyze the causes and role of right ventricle failure in the morbidity and mortality after arterial switch operation for transposition of the great arteries in neonates.

Between January 1999 and December 2001, 62 neonates underwent arterial switch operation. The simple transposition group was comprised of 39 patients with transposition of the great arteries and intact ventricular septum. The complex transposition group included 23 patients with large ventricular septal defects, accompanied with left ventricle outflow tract obstruction in 6 cases and dextrocardia in 1 case. Arterial switch operation was performed on elective basis in all but 3 patients who underwent emergency operation.

Patients with complex heart defects had significantly lower body weight (p = 0.008) than patients with simple trasposition of great arteries. The usual coronary artery pattern (ie, the left anterior descending artery and circumflex artery arising from the right aortic sinus; the right coronary artery arising from the left aortic sinus) was found in 74% of the neonates in the simple transposition group and 65% of the neonates in the complex transposition group. Age, weight, coronary artery anatomy, cardiopulmonary bypass, duration of aortic cross-clamp, bleeding, and the need for delayed chest closure did not influence the outcome of surgery. Low cardiac output after surgery was more common in the complex transposition group (p = 0.0001), although it was not a predictor of fatal outcome. Preoperative hypoxia coupled with acidosis (odds ratio (OR), 5.70; 95% confidence intervals (CI), 4.45-7.44), and emergency operations (OR, 3.62; 95% CI, 2.22-5.59) were strong predictors of unfavourable outcome. We lost 4 patients out of 62 (6.5%) because of right ventricle failure caused by persistent pulmonary hypertension. Right ventricle failure on the second postoperative day, e.g., sustained increased central venous pressure > 15 mm Hg (p < 0.001) and high velocity tricuspid regurgitation > 4 m/s (p = 0.002), indicated bad prognosis.

Difficult coronary anatomy was not a risk factor for morbidity and mortality after arterial switch operation. Poor preoperative health condition, hypoxia (despite effective balloon atrioseptostomy), and acidosis contributed to persistent pulmonary hypertension. Operation on the emergency basis and tricuspid valve insufficiency with right ventricle failure were strong predictors of unfavorable outcome.