Natural history and clinical outcome of "uncorrected" scimitar syndrome patients: a multicenter study of the italian society of pediatric cardiology.

Introduction And Objectives: To analyze the clinical status of patients with "uncorrected" scimitar syndrome in a multicenter Italian study.

Methods: The natural history of scimitar syndrome was analyzed in 44 affected individuals (from 9 Italian centers).

Results: The median age at diagnosis was 1.05 years (range, 1 day-41 years). Thirty-three patients (75%) had an isolated form; 11 patients (25%) had associated congenital heart diseases. Twenty-two patients (50%) were symptomatic at diagnosis, including respiratory symptoms (n=20) and congestive heart failure (n=6). Patients with associated congenital heart defects had a higher prevalence of congestive heart failure (4 of 11 [36.4%] vs 2 of 33 [6.1%]; P=.027), pulmonary arterial hypertension (7 of 11 [63.6%] vs 2 of 33 [6.1%]; P=.027) than patients with isolated forms. Ten patients (22.7%) underwent correction of associated cardiac defects, leaving the anomalous pulmonary venous drainage intact. The median length of follow-up after diagnosis was 6.4 years (range, 0.2-27.5 years). Two patients died, both with associated cardiac defects and severe pulmonary arterial hypertension. Of 42 survivors, 39 (92.8%) were asymptomatic at the last follow-up visit; 3 patients still complained respiratory symptoms. There was no difference between isolated and associated forms of the disease.

Conclusions: In most patients, scimitar syndrome presented as an isolated lesion with a benign outcome. Nonetheless, when associated with other cardiac defects and pulmonary arterial hypertension, there was an increased risk of congestive heart failure and mortality. Correction of associated cardiac defects (transforming "associated" into "isolated" forms), together with the therapeutic occlusion of anomalous arterial supply to the lung, led to a benign outcome comparable to that in primarily isolated forms.