Left ventricular outflow tract obstruction in TGA: treatment with LV-to-PA valved conduit

Progressive or recurrent left ventricular outflow tract obstruction after a previous Mustard or Senning operation represents a rare but challenging problem. The obstruction can be resected in some patients, but abnormal attachment of the mitral valve or a long fibromuscular tunnel represents a difficult surgical problem. Between 1979 and 1993, we encountered this type of left ventricular outflow tract obstruction in 10 patients, 4 to 13 years after the atrial repair. They ranged in age from 5 to 15 years (mean, 8.8 years) and weighed between 11.5 and 47 kg (mean, 25.3 kg). Operations were performed through a left thoracotomy with the patient on hypothermic cardiopulmonary bypass but without aortic cross-clamping. The left atrial appendage and descending aorta were cannulated. Good relief of the gradient was obtained in all patients (mean residual gradient, 14.8 mm Hg). All patients survived the operation. One patient died suddenly at home 6 months later; 2 patients required conduit replacement. All 9 long-term survivors are asymptomatic as of 6 months to 8 years after their conduit placement or replacement. We recommend the placement of a left ventricle-to-pulmonary artery valved conduit for the relief of severe left ventricular outflow tract obstruction arising after a Senning or Mustard operation that cannot be managed by other means.