The natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.

Aims: Treatment decisions in patients with scimitar syndrome (SS) are often challenging, especially in patients with isolated SS who are often asymptomatic and who might be diagnosed accidentally. We queried a large multi-institutional registry of SS patients to evaluate the natural history of this condition and to determine the efficacy of surgical treatment in terms of survival and clinical status. Methods and results: We collected data on 485 SS patients from 51 institutions; 279 (57%) patients were treated surgically (STPs) and 206 (43%) were clinically monitored (CMPs). Median age at last follow-up was 11.6 years (interquartile range 4-22 years). Overall survival probability at 30 years of age was 88% [85-92% confidence intervals (CI)] and was lower in patients with associated congenital heart disease (CHD) (P < 0.001) and pulmonary hypertension (P < 0.001). Most patients were asymptomatic at last follow-up (279/451, 62%); STPs were more frequently asymptomatic than CMPs (73% vs. 47%, P < 0.001), with fewer cardiac [odds ratio (OR) 0.42, 95% CI 0.22-0.82] and respiratory symptoms (OR 0.08, 95% CI 0.02-0.28). Many STPs (63/254, 25%) had stenosis/occlusion of the scimitar drainage, and this was associated with a younger age at surgery (OR 0.4, CI 0.21-0.78). Conclusion: Patients with SS have a high overall survival. Survival probability was lower in patients with associated CHDs and in patients with pulmonary hypertension. Surgical treatment of SS is beneficial in reducing symptoms, however, given the significant risk of post-operative scimitar drainage stenosis/occlusion, it should be tailored to a comprehensive haemodynamic evaluation and to the patient's age.