Efficacy and safety of sirolimus in the treatment of vascular anomalies: A systematic review

The management of vascular anomalies is complex and requires a multidisciplinary team with a combination of medical, surgical, and intervention treatments. Medical treatment is limited and has conflicting results. Off-label use of mammalian target of rapamycin inhibitors shows promising results. The objective of this study was to systematically evaluate the literature published about the efficacy and safety of sirolimus in the treatment of vascular anomalies. A systematic review of the published literature was conducted using the PubMed database and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. There were 73 articles included: 2 randomized controlled studies, 2 nonrandomized prospective studies, and 69 retrospective case reports and case series. In total, 373 patients were included. Sirolimus was administered topically to 56 patients and orally to 317 patients. Sirolimus was highly effective in the treatment of vascular tumors associated with Kasabach-Merritt phenomenon (95.5% of the patients clinically improved and 93% had normalization of coagulopathy), venous malformations (size reduction was observed in 88.9% of patients), and lymphatic malformations (clinical improvement in 94.9% of patients). Topical sirolimus results were conflicting. Arteriovenous malformations were not improved by sirolimus. Low-level evidence suggests that sirolimus can improve the prognosis of vascular anomalies, most notably vascular tumors associated with life-threatening coagulopathy and venous and lymphatic malformations. Further research is needed to establish the benefits of sirolimus in the management of vascular anomalies.