Purpose or Case Report: Scimitar syndrome is characterized by anomalous right pulmonary venous connection to the inferior vena cava with ipsilateral lung underdevelopment. Patients often have additional cardiac and extracardiac anomalies as part of the syndrome, leading to a wide range of clinical manifestations. Robust data about the variant anomalies and associated outcomes are lacking. We aimed to describe anatomical variations and clinical outcomes in scimitar syndrome.
Methods & Materials: Patients with scimitar syndrome underwent preoperative cross-sectional imaging between 2000 and 2025. Demographics, procedural records, imaging features, clinical course, and outcomes were reviewed. Multivariable analysis was conducted to identify associations with clinical outcomes.
Results: Of 24 patients with scimitar syndrome, nine (38%) were male and median age at diagnosis was 7.5 months [IQR 0-48.5]. Most patients (23/24, 96%) were situs solitus. Common cardiac associations included dextroposition (20/24, 83%), PDA (11/24, 46%), intracardiac shunts (9/24, 38%), and non-scimitar pulmonary vein stenosis (7/24, 29%). One patient had anomalous origin of left coronary artery from pulmonary artery. Aberrant systemic arterial supply to the ipsilateral lung was found in 17 (71%) of patients, most from the celiac axis (8/17, 47%). Horseshoe lung was the most frequent extracardiac association (13/24, 54%). Half of the patients had total right pulmonary venous drainage through the scimitar vein, most commonly to the supradiaphragmatic IVC (16/24, 67%). One patient had an atypical upside-down connection to the SVC, one had a meandering vein to the left atrium, and three patients had dual connections to both IVC and left atrium. Scimitar vein stenosis was present in 15/24 (63%) of patients, with a median diameter reduction of 34% [IQR 17.1-43.2]. Cardiac catheterization was performed in 17/24 (71%) and 7/24 (29%) required corrective surgery. In this cohort, pulmonary hypertension occurred in 18/24 (33%) and death in 3/24 (13%) . Non-scimitar pulmonary vein stenosis (p=0.001), and the percentage of scimitar vein stenosis (p=0.022) were associated with pulmonary hypertension.
Conclusions: Scimitar syndrome demonstrates diverse cardiac and extracardiac associations, with variable venous drainage patterns. Pulmonary hypertension was relatively common and associated with pulmonary vein stenosis. Despite this anatomic complexity, overall mortality remained low.