Background: Complete repair of conotruncal defects frequently uses maintenance of an interatrial communication. Postoperative right ventricular dysfunction may be characterized by elevated right atrial pressure and decreased systemic oxygen saturation owing to right-to-left shunting at the atrial level.
Methods: From January 1996 to December 2005, 112 patients younger than 6 months of age underwent complete repair of tetralogy of Fallot or truncus arteriosus. An interatrial communication was used in 80 of 112 patients (71%). Hemodynamic data were determined during the first 48 hours after surgery.
Results: In patients with an atrial communication, mean oxygen saturation reached a nadir of 94% +/- 6%, and mean arterial PO2 a nadir of 73 +/- 25 mm Hg at 16 to 24 hours after surgery; both increased during the second 24 hours. At hospital discharge, median oxygen saturation was 98% (range, 86% to 100%). During the first 48 hours, mean oxygen saturation was less than 90% in 13 patients; the only multivariate risk factor was younger patient age. Mean right atrial pressure was greater than 10 mm Hg in 30 patients; multivariate risk factors were older patient age and repair with a transannular patch.
Conclusions: After complete repair of conotruncal defects using an interatrial communication, systemic oxygenation reaches a nadir at 24 hours after surgery, and improves by the time of hospital discharge. Clinically significant desaturation occurs in a small minority of patients. Infants undergoing repair before 2 months of age are at higher risk for systemic desaturation. The effects of an interatrial communication on systemic oxygenation should not be considered a contraindication to complete repair in early infancy.