Right ventricular function after extracardiac conduit repair for tetralogy of Fallot. A comparison among surgical approaches.

Right ventricular volume measurements and hemodynamic studies were performed in 20 patients after total correction of tetralogy of Fallot. There were 6 patients with an extracardiac conduit and Hancock xenograft (G-1), 8 with an outflow tract patch (G-2) and 6 without or with a minimal right ventriculotomy and repair of pulmonary valve (G-3). The age at the time of operation was over 3 years in each patient and averaged 5 +/- 2 (mean +/- SD) years. Right ventricular systolic pressure averaged 81 +/- 22, 55 +/- 22 and 58 +/- 30 mmHg in G-1, G-2 and G-3, respectively. Right ventriculography showed no contraction of the right ventricular free wall at the anastomosis to the conduit and poor contraction around the anastomosis in G-1. The right ventricular enddiastolic volume index (RVEDVI) was 114 +/- 31, 155 +/- 57 and 115 +/- 28 ml/m2 in G-1, G-2 and G-3, respectively. The right ventricular ejection fraction (RVEF) was 0.42 +/- 0.11 in G-1, 0.53 +/- 0.04 in G-2 (p less than 0.05, vs G-1) and 0.57 +/- 0.04 in G-3 (p less than 0.02, vs G-1). Pulmonary regurgitation was evident in 17 patients, and RVEDVI correlated well with degrees of pulmonary incompetence. Fourteen patients in G-2 and G-3 were divided into G-A and G-B to evaluate right ventricular function with or without pressure overloading of the right ventricle. G-A consisted of 7 patients with a right ventricular systolic pressure of more than 50 mmHg (74 +/- 26) and G-B of 7 patients with a value less than 50 mmHg (39 +/- 4). There was no difference in RVEDVI and RVEF between G-A and G-B. RVEF was significantly lower in G-1 than G-A (p less than 0.02) and G-B (p less than 0.05). These results suggested that an extracardiac conduit with Hancock xenograft reduced the contraction of the right ventricular free wall and induced a depressed right ventricular pump function in patients with a high right ventricular pressure.