Outcome predictors and implications for management of scimitar syndrome.

BACKGROUND: Scimitar syndrome is a rare congenital anomaly. We evaluated risk factors for postoperative pulmonary vein stenosis or death and predictive factors for survival without scimitar vein surgery in patients with scimitar syndrome.
METHODS: The records of patients with scimitar syndrome evaluated at our medical center between 1964 and 2011 were reviewed.
RESULTS: Scimitar syndrome was identified in 80 patients, with a median follow-up of 4.5 years. Patients presenting less than 1 year of age had a higher incidence of symptoms, aortopulmonary collaterals, coexisting congenital heart disease (CHD), extracardiac anomalies, and pulmonary hypertension. Of 36 patients having scimitar vein surgery, 18 had postoperative pulmonary vein obstruction that occurred with similar frequency after baffle or reimplantation procedures, early or late in the study period, and tended to be more common in infants (P = .10). Overall, 19 (24%) of 80 died. Multivariate risk factors for death included systolic pulmonary pressure >0.5 systemic level (P = .007) and left pulmonary vein stenosis (P = .009). Pulmonary artery systolic pressure <0.5 systemic level (P = .01) and absence of CHD excluding atrial septal defect (P = .01) were predictive factors in 28 patients who survived and did not have scimitar vein surgery; these patients had no or mild right ventricular dilation and a ratio of pulmonary-to-systemic flow <1.6 either at baseline, after coiling aortopulmonary collaterals or nonscimitar vein intervention.
CONCLUSIONS: Postoperative pulmonary vein obstruction is common after scimitar vein surgery regardless of redirection technique. Pulmonary hypertension and left pulmonary vein stenosis are risk factors for death, whereas patients without significant pulmonary hypertension or associated CHD did well without scimitar vein surgery. These observations may guide management decisions in patients with scimitar syndrome.