Sirolimus Use in Pediatric Vascular Anomalies: Morbidity and Mortality in a Cohort at Phoenix Children’s and Review of the Literature

Objective(s): Describe patient characteristics, mortality, and health care utilization outcomes in pediatric/young adult patients with vascular anomalies (VA) treated with sirolimus at Phoenix Children’s (PC). Methods: A retrospective review of patients under 25 years of age who received sirolimus for VA from January 01, 2014 to April 19, 2022. Descriptive statistics summarized patient demographics, VA diagnosis, VA location, and monthly rates of emergency department (ED) visits, hospitalizations, and pediatric intensive care unit admissions while on sirolimus. Associations of VA location with health care utilization were assessed using 2-sided Wilcoxon rank sum tests. Results: Our cohort consisted of 35 patients, with 19 (54.3%) females, a mean (SD) age of 5.90 (6.30) years, treated with sirolimus for a mean of 27.9 (17.8) months. VA diagnoses included venous malformations (n = 1), lymphatic malformations (n = 15), venous-lymphatic malformations (n = 12), and kaposiform hemangioendotheliomas (n = 7). Overall, the mean SD of monthly rates was 0.11 (0.14) ED visits, 0.07 (0.13) hospitalizations, and 0.01 (0.03) pediatric intensive care unit admissions. Patients with VA in the beard area had a higher median monthly rate of ED visits (0.33 vs 0.04, P = 0.02) and hospitalizations (0.27 vs 0.0, P = 0.02). One death occurred in a patient with a lymphatic malformation located in the chest, neck, and beard area with intraoral involvement. Conclusions: Higher monthly rates of ED visits and hospitalizations were detected for patients with VA in the beard area, warranting further study. Level of Evidence: Level III.