Management of coagulopathy of KHE
Management of KMP is emergent as it may result in life-threatening bleeding complications (Table 2). Although surgical resection can result in cure, this is often unsafe due to coagulopathy and the extensive, infiltrative nature of the KHE. Embolization has also been successful in select cases28. However, medical management by a hematologist is currently the standard in the US. There are no randomized clinical trials for KHE and therefore most of the evidence for treatment is through expert opinions or observational studies. Historically corticosteroids have been successful in initial management of KMP but is rarely successful as monotherapy29. Due to adverse effects of prolonged corticosteroids in infants and young children, the dose should be weaned rapidly once evidence of control of coagulopathy. Vincristine in combination with corticosteroids has been recommended in previous consensus statements to be the treatment of choice but has recently been supplanted by sirolimus (plus corticosteroids) as the first line choice17,30,31. A randomized control trial of vincristine versus sirolimus was discontinued early due to poor accrual primarily because of the provider and family preference of sirolimus despite lack of rigorous evidence. Vincristine is now primarily preferred for refractory or recurrent cases. Topical sirolimus or tacrolimus have been shown in small studies to be beneficial for superficial cutaneous lesions32,33. Antiplatelet therapy such as aspirin or ticlopidine in combination with vincristine have also shown success34-37. Although it appears counterintuitive to most hematologists to treat a patient with severe thrombocytopenia with antiplatelet agents, this may be an option to prevent continued platelet aggregation and activation as this is the primary trigger for the coagulopathy. Antiplatelet therapy is used more frequently in European centers and has not been widely adopted in North American centers. However, for cases refractory to corticosteroids and/or sirolimus or recurrent KMP upon tapering current medical therapy, antiplatelet therapy should be considered as an adjuvant. Some reports of fibrinolytic agents have been reported38, but we do not currently routinely recommend these therapies.
Supportive care is critically important in the early management of KMP. Platelet transfusions should be avoided unless indicated for severe bleeding or prior to biopsy or resection17. Platelets contain pro-angiogenic growth factor which may potentiate growth of the vascular lesion. In addition, the transfused platelets will be further trapped within the lesion resulting in further immediate growth and will promote activation and consumption of coagulation factors39,40. It is generally accepted that cryoprecipitate or fresh frozen plasma be transfused for active bleeding or prior to procedures if the fibrinogen is less than 100mg/dL. Routine administration of cryoprecipitate for asymptomatic mild hypofibrinogenemia is not indicated. Transfusion of packed red blood cells is indicated for severe or symptomatic anemia17.