Published online by Cambridge University Press: 19 August 2008
Obstruction to the pulmonary venous return is a frequent associated anomaly in patients with isomerism of the right atrial appendages. Yet, preoperative diagnosis by means of either cross-sectional echocardiography or cardiac catheterization can be intriguing. Indeed, the presence of two morphologically right lungs reduce considerably the size of window for precordial echocardiography. Also, in the presence of severe pulmonary stenosis or atresia, it can be difficult at cardiac catheterization to enter the pulmonary trunk. In these patients, construction of a systemic-to-pulmonary artery anastomosis will almost inevitably result in pulmonary edema. Between May 1984 and December 1988, five patients with isomerism of the right atrial appendages, severely decreased pulmonary blood flow and concealed obstruction to the pulmonary venous return were admitted to our hospital. A modified Blalock Taussig shunt by interposition of a polytetrafluoroethylene prosthesis was performed in each patients and all of them developed pulmonary edema. Three patients died despite appropriate medical treatment. The remaining two patients were successfully treated by banding of the Blalock shunt. This was performed in the first patient at the time of the initial surgery, when prior to closure of chest, pulmonary edema became manifest. The second patient who developed pulmonary edema early postoperatively, underwent cardiac catheterization to confirm the clinical diagnosis of obstruction to the pulmonary venous return. Reduction of blood flow through the Blalock shunt with resolution of edema was initially achieved by means of a partially occluding balloon catheter. Pulmonary edema recurred one week later because of rupture of the balloon and the patient eventually underwent a successful banding of the Blalock shunt through a left thoracotomy. We conclude that preoperative assessment of the pulmonary venous return is mandatory in patients with right isomerism and reduced pulmonary blood flow. Construction of a modified Blalock-Taussig shunt in the presence of concealed obstruction to the pulmonary venous return will almost inevitably cause pulmonary edema. Banding of the Blalock shunt can be successful, as observed in our experience, for the management of this serious complication.