Predictive Value of Intraoperative Diagnosis of Residual Ventricular Septal Defects by Transesophageal Echocardiography

Background. Intraoperative transesophageal echocardiography (IOTEE) is well established as a monitoring tool during ventricular septal defect (VSD) repair to ensure complete closure of the defect. Residual shunts detected by IOTEE are common. The predictive value of IOTEE findings on the long-term course of residual shunts is not well documented, especially in regard to the need for reoperation or bacterial endocarditis prophylaxis. The objective of this study is to determine the predictive value of intraoperative IOTEE diagnosis of residual VSDs and therefore delineating the natural history of these findings. Methods. Retrospective review of IOTEE reports of 690 consecutive patients with VSD (isolated or part of a complex lesion) was undertaken. Those were compared with transthoracic echocardiographic reports of these patients before their discharge from the hospital, and the most recent transthoracic echocardiographic examination. Positive and negative predictive values, sensitivity, and specificity of such diagnoses were then calculated from predischarge and from follow-up transthoracic echocardiographic data. Results. There were 260 of 690 patients with a residual VSD on IOTEE; 24 required repeat cardiopulmonary bypass for complete closure. There were 573 patients with predischarge transthoracic echocardiographic examination; 296 had residual VSDs (125 not detected by IOTEE), and 13 defects required reoperation during the same hospitalization, 5 of which were detected by IOTEE. The positive and negative predictive values were 78\% and 65\%, respectively. Follow-up transthoracic echocardiographic examination of 383 local patients showed residual VSD in 57 (37 not detected by IOTEE), with positive and negative predictive values of 15\% and 83\%, respectively. Conclusions. Although IOTEE is sensitive enough to detect residual VSD shunts in many patients (37\% of this cohort), the majority of these defects are trivial and resolve spontaneously, with a positive predictive value of only 15\% on follow-up transthoracic echocardiographic examination and a rare need for reoperation.