Peginterferon Alfa 2a: Treatment Option for Coagulopathy Associated with Vascular Malformation?.

We applied peginterferon alfa 2a for off label use therapy in a 44 year old male patient (pat.) with extensive venous malformation (VM) and associated localized intravascular coagulation (LIC). Since birth he had huge VMs in the left leg and left lower abdomen. During surgery and tooth extraction he had severe bleeding complications. In 2003 he reported a sensation of continually growing VMs and requested for therapy.

Clinical findings (examination, contrast medium CT) showed no considerable growth of VMs in comparison to former examinations. Laboratory findings were low fibrinogen, low factor VIII activity (FVIII:C) and factor XIII activity (FXIII:C), prolonged aPTT, mild thrombocytopenia and elevated d-dimers. Vascular surgeons disadvised another surgery. LMWH therapy had been carried out before and was ineffective considering coagulopathy and sizereduction of vascular malformations. Considering antiproliferative properties we decided for off label use therapy with peginterferon alfa 2a (Pegasys), 180 μg once a week. Therapy started September 2004 and was applied for 16 weeks. Laboratory tests, clinical examination and photo documentation were done before, during and after therapy.

During and after therapy laboratory findings showed normalization of fibrinogen, FVIII:C levels, aPTT and rising FXIII:C levels. We saw no significant change of VMs in clinical examination and photographs. The pat. reported no sense of vascular size reduction but also no sense of growing malformations. Due to interferon side effects such as lowered blood count, therapy was finished after 16 weeks.

In conclusion the LIC in the VMs seemed to improve under interferon therapy with normalization of fibrinogen and FVIII:C. Even though there was no significant size reduction of VMs yet, this therapy could be an important treatment option for normalization of coagulation parameters e.g. before surgery. In our patient interferon therapy seemed to be more effective than LMWH therapy. In literature only heparin was reported to be effective in coagulopathies associated with VMs, not interferon. Therefore the positive laboratory findings in our patient are remarkable.