Intraoperative prebypass and postbypass epicardial color flow imaging in the repair of atrioventricular septal defects

Abstract

The use of intraoperative epicardial Doppler echocardiography with color flow imaging both before and after cardiopulmonary bypass to assist repair of congenital heart defects in infants and small children has not been reported. To demonstrate its simplicity and utility, we obtained immediately prebypass and postbypass examinations from 18 consecutive patients undergoing repair of atrioventricular septal defects between March 1987 and March 1988 (aged newborn to 3 years, smallest 2.4 kg, 11 patients less than 1 year old). Direct application of a sterile transducer to the epicardial surface eliminates any restriction imposed by the transesophageal approach, and the routine use of color flow imaging enables the operating surgeon to directly evaluate intracardiac anatomy and flows in a variety of orientations. Average examination time was 3.95 +/- 1.96 minutes. Prebypass studies disclosed that a short-axis inspection through the common atrioventricular valve orifice produced a unique visualization of the dynamic commitments of atrioventricular valve tissue throughout systole and diastole that was helpful in planning valve allocation during repair. In addition, echocardiography demonstrated features not previously appreciated in seven of 18 patients (39%). In all, image quality and resolution were vastly superior to preoperative chest wall studies. Postbypass studies revealed significant residual interventricular shunts in two of 18 patients (11%). Views obtained from various orientations directed specific and efficient repair immediately so that all patients left the operating room with documented, surgically acceptable results. Comparison of ventricular function between prebypass and postbypass studies enabled appropriate application of pharmacologic agents in the operating room if necessary. All patients survived their operation. There have been two late deaths, and 16 patients are alive and doing well (follow-up: 9 to 21 months). These experiences indicate that intraoperative epicardial Doppler color flow imaging (1) can be easily learned and applied by the surgeon, (2) enhances the repair of atrioventricular septal defect by providing unique spatial, anatomic, and flow information in the beating heart at the time of repair, (3) increases confidence of a surgically acceptable repair before the patients leave the operating room, (4) guides specific surgical or anesthetic adjustments to optimize results, and (5) works as a valuable aid that may help reduce poor results in the repair of complex congenital cardiac lesions.