Purpose or Case Report: Norwood procedure is a 3-stage surgical palliation for patients with functionally single ventricle anatomy, most commonly hypoplastic left heart syndrome. Complications after stage I operation are not uncommon and include Blalock Taussig Thomas (BTT) /Sano shunt abnormalities, Damus-Kaye-Stansel (DKS) anastomotic narrowing, and neo-aortic arch /branch vessel stenosis. Transthoracic echocardiography (TTE) is traditionally the mainstay for evaluation. The purpose of our study is to compare Gated Cardiac Computed Tomographic Angiography (CCTA) with TTE when evaluating post-operative complications after stage I Norwood procedure and implications of CCTA findings on management.

Methods & Materials: We performed a retrospective chart review of all patients who underwent urgent CCTA for suspected complications related to stage I Norwood procedure over a 4-year period. Elective Pre-Glenn CCTA’s were excluded. Patient demographics, CCTA findings, TTE findings, as well as interventions performed were recorded.

Results: 34 patients were included. Male to female ratio was 1:1. The mean age at CCTA was 63 days (range 4-210 days). All patients had a prior TTE with the mean time interval between TTE and CCTA of 2 days (range 0-9 days). CCTA detected 57 abnormalities in 30 patients, with 23 directly related to post-surgical complications including shunt related complications (10/23, 43%), DKS anastomotic narrowing (2/23, 9%), and neo-aortic arch/branch vessel abnormalities (11/23, 48%). The 23 complications were managed as follows: surgery (9, 39%), catheter-based intervention (7, 30%), medical/no change in management (7, 30%). TTE missed 10/23 (43%) findings detected by CCTA of which 50% had direct surgical/interventional implications, either managed with surgery (3/10, 30%) or catheter-based intervention (2/10, 20%).

Conclusions: CCTA plays an important role in detecting surgical complications after stage I Norwood procedure, and identifies additional findings compared to TTE that have direct surgical/interventional implications. CCTA should be part of imaging algorithm in imaging these patients.