Subtherapeutic doses of low-molecular-weight heparin (LMWH) appear to be safe for use among patients with slow-flow vascular malformations (SFVMs) undergoing sclerotherapy, though further research is needed, according to research published in Pediatric Blood & Cancer.

Vascular malformations affect about 1.5% of the general population, and are associated with a series of hematological complications, including coagulopathy. Coagulation abnormalities are the most common with SFVMs, which are associated with localized intravascular coagulopathy (LIC). LIC can involve a series of serious complications, including deep vein thrombosis, pulmonary embolism, hemorrhage during procedures, and disseminated intravascular coagulopathy, the latter of which can be fatal in up to half of patients.

First-line treatment of symptomatic SFVM often involves sclerotherapy, which can cause development of thrombin and fibrin clot. LMWH is, furthermore, often used in a periprocedural manner, though scientific data do not explicitly support this addition.

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For this study, researchers aimed to “better characterize the hematologic complications of sclerotherapy that occur in patients with SFVM and evidence of LIC who received and did not receive periprocedural LMWH.”

All data were analyzed retrospectively and were obtained from patients undergoing sclerotherapy between 2008 and 2016, and who had both SFVM and LIC. A total of 304 patients who underwent sclerotherapy were identified; 59 patients with SFVM had evidence of LIC (median age at time of procedure, 11.4 years).

The 59 patients underwent 281 sclerotherapy procedures, and 85% of patients received periprocedural LMWH. Among the 86% of patients who were considered pediatric, no thrombotic complications were noted. One adult patient developed multiple pulmonary emboli post-procedure. Fibrinogen levels fell below 100 mg/dL after sclerotherapy in 4 patients, leading to the need for cryoprecipitate.

In addition, 1 patient had sclerotherapy-induced hemolysis and required packed red blood cell transfusion. Intraoperative bleeding or thrombotic events were not reported.

While appearing safe, the authors noted that closer investigation of the consequences of LMWH use in this setting is necessary.


Ricci KW, Chute C, Hammill AM, Dasgupta R, Patel M. Retrospective study of hematologic complications in patients with slow-flow vascular malformations undergoing sclerotherapy. Pediatr Blood Cancer. Published online August 11, 2020. doi:10.1002/pbc.28277