Influence of ventricular septal defect type on surgical results in children with tetralogy of fallot

Background. Tetralogy of Fallot (TOF) with subpulmonary ventricular septal defects (VSD) is relatively more common among Orientals than among Occidentals. This study assessed the influence of type of VSD on surgical results in children with TOF. Methods. Fifty-one patients with TOF (age range, 14 months to 11 years, mean 40.7 months, median 30 months, 29 boys, 22 girls) who underwent total correction by a single surgeon between January 1992 and December 1995 were retrospectively studied. Of the 51 patients, 17 patients with subpulmonary VSD were classified as group I. The remaining 34 patients with perimembranous VSD were classified as group II. All patients underwent a combined transatrial and transpulmonary surgical approach. Early postoperative results were evaluated 7 to 10 days after surgery and late postoperative results were evaluated 1 year after surgery. Results. There were no statistically significant differences between the two groups in age, sex, body weight, pulmonary to systemic flow ratio, pulmonary to aortic annulus diameter ratio or preceding palliative shunt or balloon pulmonary valvuloplasty. Nevertheless, group I patients had better oxygen saturation preoperatively (84.2 ± 4.4% vs 80.3 ± 7.6%, p = 0.037). During surgery, the transannular patch rate was higher in group I (100% vs 73.5%, p = 0.003). The cardiopulmonary bypass time, postoperative stay in the intensive care unit, duration of chest tube placement, early postoperative residual VSD rate, and early and late postoperative residual pulmonary stenosis rate were not significantly different between the groups. However, late postoperative residual VSD rate was 33.3% in group I and 6.45% in group II, which was statistically significant (p = 0.029). There were no significant differences in arrhythmia between the two groups. Conclusions. Patients with TOF with subpulmonary VSD had a better preoperative oxygenation, higher transannular patch rate during surgery and a higher incidence of late residual VSD than those with TOF with perimembranous VSD.