Serial Lung Perfusion Scintigraphy After Unifocalization and Repair of Tetralogy of Fallot With Major Aortopulmonary Collaterals

Background In patients with tetralogy of Fallot and major aortopulmonary collaterals (MAPCAs), pulmonary blood supply is highly variable. Our approach to this condition emphasizes complete unifocalization of the pulmonary circulation, incorporating all lung segments and addressing stenoses out to the segmental level. Post-repair, we recommend serial lung perfusion scintigraphy (LPS) to assess short-term changes in pulmonary blood flow distribution. Methods We reviewed post-discharge and follow-up LPS performed through three years post-repair and analyzed serial changes in perfusion, risk factors for change, and the relationship between LPS parameters and pulmonary artery reintervention. Results Of 543 patients who had postoperative LPS results in our system, 317 (58%) had only a predischarge LPS available for review, while 226 had 1 (20%) or more (22%) follow-up scans within three years. Overall, pulmonary flow distribution prior to discharge was balanced, and there was minimal change over time; however, there was considerable patient-to-patient variation in both metrics. On multivariable mixed modeling, time after repair (P = .025), initial anatomy consisting of a ductus arteriosus to one lung (P