Evaluation of ventricular septal defect by transesophageal echocardiography: Intraoperative assessment

The miniaturization of transesophageal echocardiography (TEE) probes, together with the development of the capability for biplane imaging from the esophagus, have increased the use of TEE in pediatric cardiology. The aim of this study was to evaluate the TEE findings in patients with ventricular septal defect (VSD) before and after closure primarily by means of pediatric biplane probes. This study group included 69 patients who underwent VSD closure as an isolated repair or as a part of a definitive repair of a more complicated lesion. Ages ranged from 6 days to 15.6 years (median 1 year, 4 months), with operative weights ranging from 2.9 kg to 68 kg (median 10 kg). Preoperative and follow-up transthoracic echocardiograms (TTE) were also performed. Intraoperative TEE was performed without complication in all 69 patients. Preoperative results: (1) anatomic findings: Two muscular VSDs were detected by matrix TEE but could not be observed by TTE. A patient with preoperative TTE diagnosis of an ostium primum ASD was found to have atrioventricular (AV) canal by TEE. In three of six AV canal type VSDs, both TTE and TEE demonstrated left ventricular-right atrial shunting (2) aortic regurgitation associated with VSD: Aortic regurgitation as a result of right coronary cusp prolapse was detected in one of five supracristal VSDs in which the biplane or matrix TEE was used. In another two patients with perimembranous VSD, coronary cusp prolapse was detectable only by TEE, but no regurgitation was found; (3) tricuspid valve pouch/aneurysm/straddling and chordal attachment: In 19 of 30 cases with perimembranous VSD and two of 6 cases with AV canal VSDs, the presence of a TV pouch was detected by TEE. Six of these 21 pouches were not seen on the TTe examination. In a patient with AV canal VSD, TV straddling was observed only by TEE; (4) diameter measurements (comparison between TTE and TEE): A moderate correlation was found when the largest VSD diameter measured in any plane by TTE was compared to the largest diameter measured by TEE (r = 0.76, p < 0.01) in 26 perimembranous VSDs. There was good agreement between diameter measurements obtained by TTE and TEE except with AV canal VSDs, where TEE diameter (especially transverse plane) was consistently larger than the TTE diameter, although the number of patients was too small for statistical analysis. Postoperative results: Residual leaks and additional VSDs: In 25 patients residual leaks were diagnosed by TEE (23 of these were considered to be hemodynamically insignificant). The remaining two were recognized to be clinically important and reoperated before the chest was closed. Intraoperative TEE with biplane capability is of significant value in defining anatomic features and physiologic characteristics of flow through VSDs.