Arterial switch operation after mustard procedures in adult patients with transposition of the great arteries: is it time to revise our strategy?

Background After the Mustard or Senning procedure, adults with transposition of the great arteries may have right ventricular failure and require consideration of new therapies. A 2-stage arterial switch operation (ASO) may be performed as an alternative to heart transplantation. This procedure is relatively successful in children, but little is known about the 2-stage ASO in adults. We report our experience in adults undergoing pulmonary arterial banding as the first stage of a planned 2-stage arterial switch procedure after a failed Mustard operation. Methods and results Three adult patients with systemic right ventricular failure late after Mustard procedures embarked, through pulmonary artery banding, on a course toward a 2-stage arterial switch at the Toronto General Hospital. Baseline clinical characteristics as well as preoperative hemodynamics were reviewed. Immediate perioperative and postoperative events, hemodynamic measurements, and clinical outcomes were also recorded. Two patients were banded acutely such that their morphologic left ventricular to right ventricular (LV/RV) systolic pressure ratios were >0.65 after the initial banding procedure. The subpulmonary left ventricle failed in both cases. In contrast, the third patient had a more gradual approach to pulmonary artery banding (PAB), with an initial LV/RV pressure ratio of 0.5, which eventually led to a successful conversion to an arterial switch procedure. Conclusions Our evidence suggests that in adult patients expected to undergo a 2-stage arterial switch procedure after a failed Mustard operation, acute PAB achieving near-systemic subpulmonary LV pressure leads rapidly to ventricular failure and failure of this treatment strategy. A more gradual approach to PAB may be required to achieve a successful outcome.