Prediction of severe obstruction to right ventricular outflow after repair of tetralogy of Fallot and pulmonary atresia

Cineangiograms were available for a quantitative retrospective study along with complete clinical information in 96 patients who underwent intracardiac repair of tetralogy of Fallot with pulmonary atresia. Multivariate analysis determined that the risk factors for too high a ratio (greater than or equal to 1) between the peak pressure in the right ventricle and that in the left, in the operating room about 30 minutes after repair, were as follows: size of the patient, small size of the right and left pulmonary arteries, and a larger number of large aortopulmonary collateral arteries. When, according to the multivariate equation, the predicted probability of this ratio being equal to or greater than 1 is 50% or more, consideration may be given to preliminary operations before repair; when the predicted probability is 70% or more, complete repair at that stage may be unwise.