Evaluation of ventricular septal defect repair using intraoperative transesophageal echocardiography: Frequency and significance of residual defects in infants and children

Intraoperative transesophageal echocardiography (IOTEE) is commonly used to assess for residual defect and the need to return to bypass after repair o f ventricular septal defect (VSD). The frequency and significance of residu al septal defects as noted on IOTEE has not been, well defined. We evaluate d the frequency of residual VSD via IOTEE and the relationship between size of a residual VSD and rate of reoperation. In addition, we looked at the r elationship between, the presence of a residual VSD via IOTEE and the prese nce of residual VSD at follow-up transthoracic echocardiography (TTE). Resi dual VSD teas measured via the Largest width of the Doppler color jet diame ter originating at the left ventricular septal surface. Of the 294 patients evaluated with IOTEE after VSD repair, one-third had a residual defect by IOTEE Doppler color flow mapping. Two-thirds of these defects closed sponta neously on TTE by the time of hospital discharge. There was no difference i n frequency of residual VSD between simple (VSD closure alone, n = 90) and complex (VSD with associated lesions, n = 204) repair. Return to bypass wit h immediate reoperation was undertaken in nine patients, all of whom had si gnificant shunt via oximetry (Qp/Qs > 1.5:1.0). All had residual VSD color jet diameters > 3 mm. Seven patients had residual color jet equal to 3 mm; however, hemodynamic studies did not reveal a significant shunt and none of these had reoperation. Seven, patients with no VSD or < 3 mm residual VSD via had late reoperation to close residual VSD at 4 days to 5 months after initial operation. These were due to patch dehiscence or development of an "intramural" VSD in patients with conotruncal anomaly. A residual defect on IOTEE color Doppler measuring <greater than or equal to> 4 mm predicts the need for immediate reoperation, while a 3 mm defect may be significant and requires additional intraoperative hemodynamic evaluation. The majority of small defects noted on IOTEE are not present at discharge TTE. Patients wi th conotruncal defect repair should be followed closely for development of late significant "intramural" defects.