Objective (69) The occurrence of unpredictable pain crises are the principal determinant of the quality of life for patients with venous malformations (VM). A definite coagulation phenomenon, characterized by an increase in D-dimer levels and the presence of phleboliths within the malformation, has been previously reported. By applying Virchow’s triad and evaluating intralesional samples, our objective is to delineate the coagulation profile and the extent of endothelial dysfunction within the malformation. Methods (42) With the authorization of the Ethics Committee, a research project was undertaken on intralesional and extralesional blood samples from 30 pediatric patients afflicted with spongiform VM. Thromboelastometry analyses were performed using ROTEM ® Sigma, and the concentration of syndecan-1 was determined by ELISA. Results (80) In the ROTEM ® analyses, the A5, A10, and MCF values were below the established reference ranges in the intralesional samples in both the EXTEM and INTEM assays indicating that intralesional clots had significant instability. Furthermore, during the investigation of the delayed fibrinolysis phase using recombinant tissue plasminogen activator (rtPA) in EXTEM analysis, widespread hyperfibrinolysis was observed intralesional. Additionally, analysis of syndecan-1 showed significant differences between extralesional and intralesional levels (p<0.026) and controls (p<0.03), suggesting differences in the state of endothelium. Conclusions (39) For the first time, we developed a comprehensive understanding of the coagulopathic profile of VM and the role of endothelial dysfunction in its pathogenesis. These findings will enable the implementation of targeted therapies based on the individual coagulation profiles.

Introduction Sirolimus has become the third leg in the treatment of vascular anomalies, initially relegated as rescue therapy for refractory lesions but lately recommended as first line. Our objective is to determine when it is best to start sirolimus treatment. Methods A retrospective review of patients with vascular anomalies treated with sirolimus during a 9-year period was performed. The variables analyzed included subtype of vascular anomaly, age at the start of treatment, sirolimus dosage and levels, response and duration of treatment among others. Results 129 patients were included and classified according to ISSVA in: tumor (7), lymphatic malformation (60), venous malformation (16), combined malformations (26), others (22). Overall response was positive in 90.8%. Median duration of treatment was 5.5 months (0-110). Response was not influenced by dosage and levels, neither by subtype of vascular anomaly, location, extension or symptoms. However the lower the age of starting sirolimus, the better the response, mainly under 5 years of age (p=0.004). At 6 months 67% of patients had responded while at 12 months over 84% did. By age, patients under 5 years showed positive response at a median time of 2 months, compared to 5 and 7 months from older patients. Time until a positive response was not influenced by subtype neither by severity. Conclusion Overall response to sirolimus was good and most patients responded irrespective of their severity in location, extension or symptoms. Patients under 5 years old respond better and faster making our goal to attempt for an early treatment.