Predictors of postoperative ventricular dysfunction in infants who have undergone primary repair of a ventricular septal defect

By means of postoperative redionuclide angiography we identified a subset of infants undergoing primary repair of their ventricular septal defects (VSD) who had postoperative morbidity and ventricular dysfunction. Twenty-three consecutive infants undergoing repair of an uncomplicated VSD were studied. Radionuclide-determined postoperative ventricular dysfunction (VD), as defined by a left ventricular ejection fraction less than 0.30 2 to 4 hours after surgery, was correlated with clinical signs of postoperative morbidity. Six patients developed postoperative VD. Clinical correlates of VD included the use of postoperative inotropic support, increased number of postoperative intensive care days, and a low growth rate 3 months postoperatively. Potential predictors of VD were evaluated. A preoperative pulmonary-to-systemic blood flow ratio (Qp/Qs) greater than 3.0 and a pulmonary-to-systemic vascular resistance ratio (Rp/Rs) less than 0.20, taken in combination, gave a positive predictive value for VD of 100%. It is concluded that the preoperative Qp/Qs and Rp/Rs can be used to predict those infants at risk for postoperative morbidity following repair of their VSD.