Hemodynamic and angiographic findings following arterial switch repair for complete transposition

The arterial switch operation is the treatment of choice for complete transposition, and for the Taussig-Bing anomaly, with good early and mid-term results. This retrospective study examined the findings obtained at routine follow-up cardiac catheterization after primary arterial switch repair. We catheterized 111 patients after a mean of 16.9 months after surgery. These included 67 patients with an intact ventricular septum, 33 with a ventricular septal defect, and 11 with the Taussig-Bing anomaly. Right ventricular pressures were mildly elevated (mean 33.9±10.2 mm Hg) in the overall group with a mean pressure ratio between right and left ventricles of 0.34±0.1. Of the patients 74% had gradients across the right ventricular outflow tract of under 20 mm Hg, while three (2.7%) had gradients over 30 mm Hg. A significant gradient across the left ventricular outflow tract occurred in one patient (0.9%), while significant neo-aortic stenosis was not seen. The neo-aortic root remained dilated, with mild aortic valvar incompetence being seen in 12%, with none having higher grades of regurgitation. Left ventricular ejection fraction was normal in all patients, while left ventricular end-diastolic pressure was elevated in 38%. Coronary arterial stenosis was not seen, but one patient (0.9%) had left ventricular apical dyskinesia. Overall, therefore, we conclude that cardiac hemodynamics and ventricular systolic function after primary arterial switch are good. Minor gradients to the pulmonary arteries, and mild neo-aortic valvar incompetence were commonly noted. Left ventricular end-diastolic pressure was elevated in over a third of the patients. These subclinical and subtle abnormalities warrant ongoing follow-up to determine their long-term significance.