Vascular endothelial growth factor, tissue factor, coagulation and fibrinolysis markers in slow-flow vascular malformations: a prospective study of treatment with sirolimus.

Slow-flow vascular malformations (VMs), especially those with venous components, can be complicated by localized intravascular coagulopathy (LIC), responsible for pain and impaired quality of life. Several studies have shown the effectiveness of mTOR inhibitors (especially sirolimus) on slow-flow VMs but its effect on coagulation has been poorly studied, especially in children. Our study shows that venous and combined VMs are associated with coagulation abnormalities and provides novel evidence that sirolimus improves coagulopathy in venous malformations. However we did not clearly evidence predictive biomarkers of response to sirolimus but this is the first study attempting to highlight predictive markers of response to sirolimus.