Cardiac Magnetic Resonance Imaging in the Evaluation and Management of Scimitar Syndrome.

Background: Scimitar syndrome (ScS) features a partial anomalous pulmonary venous connection to the inferior vena cava, with possible septal defects, right lung hypoplasia, and aortopulmonary collaterals. We hypothesize that cardiac magnetic resonance imaging measurements can elucidate ScS physiology and guide surgical decisions. Methods: This retrospective cohort study included 26 patients diagnosed with ScS from 2011 to 2022 at Children's Hospital of Philadelphia. Patients with single-ventricle physiology were excluded. Medical records were reviewed for patient characteristics and cardiac magnetic resonance imaging data. Results: Indexed right ventricular end-diastolic volume (RVEDV) (P = .007) and indexed total shunt volume (P = .029) were significantly greater in the surgical group vs the nonsurgical group. Total shunt volume had a moderate effect (0.43), and RVEDV had a large effect (0.55) on surgery. Conclusions: These cardiac magnetic resonance imaging-derived measurements demonstrate that patients with surgically corrected ScS had a higher total pulmonary blood flow, total systemic blood flow, and significantly greater RVEDVs and total shunt volumes. RVEDV had the largest effect on surgery. These data mark a primary step in developing diagnostic criteria for ScS surgery referral using cardiac magnetic resonance imaging-derived measurements. Further research is needed to determine clinical cutoffs.