Pain management
Treatment with compression is usually the first intervention for pain secondary to a vascular malformation. Subsequently, systemic treatment of pain is targeted at associated phleboliths and localized intra-lesion thrombosis. Aspirin, an antiplatelet agent, was initially used and shown to be helpful in a subset of patients41. With an increased severity in pain and evidence of phleboliths, LMWH is commonly prescribed. In recent years, newer oral anticoagulants such as rivaroxaban have become available. Rivaroxaban, a direct factor Xa inhibitor can prevent and treat venous thrombosis. At this time, all anticoagulants used in the standard of care for pediatric population are prescribed without formal FDA-approved indication. By directly inhibiting the coagulation factors, it should have clinical efficacy equivalent to heparins. Several case reports of pediatric and adult patients with slow-flow vascular malformations refractory to LMWH had improvement in LIC and pain from rivaroxaban42-44. Sirolimus therapy has also been shown to improve pain and LIC in some patients with slow-flow vascular malformations15,30.
VTE prophylaxis and management of pain
Management for VTE risk and pain due to microthrombi secondary to LIC begins with conservative management utilizing compression garments to help flow return, decrease stagnant blood flow and maintain integrity of the flaccid vessel45,46. The approach in our practice is that treatment for pain should be considered if there is evidence of LIC (D-dimer > 2 times ULN) and/or one or more of the following: decreased fibrinogen, decreased platelet count, presence of phleboliths, or localized pain. Anticoagulation may be initiated at the following recommended doses according to our practice:
- LMWH 0.5 mg/kg/dose every 12 hours, increase to 1 mg/kg/dose every 12 hours at 2 weeks if no or minimal benefit
OR
- Rivaroxaban 10 mg PO daily, increase to 15 mg at 2 weeks if no or minimal benefit (for patients >50kg and 15 years of age)
Duration of anticoagulation can vary from a minimum of 2 weeks to long-term treatment. Follow up is recommended at 2 weeks, 4 weeks, 12 weeks and every 3 months until off anticoagulation. This approach is currently being investigated in a multi-institutional prospective clinical trial. [Figure 3]