Venous malformations are dilated veins or abnormal clusters of dilated veins that can occur in utero. In some patients there is a hereditary component, while other patients have no family history of venous malformations. As patients grow, these abnormal veins can slowly dilate, causing visible distortion of the overlying skin as the veins swell with blood. Gravity usually plays a major role in slow enlargement of the veins, and elevation of the involved body part usually results in a decrease in size as the veins empty. Blunt trauma can cause the rupture of these weak dilated vessels, resulting in hematomas.
Patients with venous malformations are particularly susceptible to clots, as the blood flow is very sluggish in the affected veins. Your doctor may request a variety of blood tests (PT, PTT, fibrinogen, and D-dimer) to check the severity of a clotting condition and monitor for potential complications. Patients with localized clots in their abnormal vessels may have prolonged clotting times, measured by protime (PT) and partial thromboplastin time (PTT); reduced amounts of clotting chemicals such as fibrinogen; and increased amounts of a clotting breakdown product known as D-dimer. If your child’s blood test results are abnormal, consultation with hematology is usually recommended.
Conservative treatment of vascular malformations consists of the use of compression garments. Non-steroidal anti-inflammatory medication can reduce the pain caused by clotted vessels and help to decrease the tendency of the blood to clot.
An MRI scan, and sometimes an MR vein scan, will help to confirm the size and extent of the abnormal veins. Depending upon the type of venous malformation, patients may greatly benefit from sclerotherapy, a technique that most commonly involves injection of sodium sotradecyl sulfate into the veins. This chemical creates a foam that leads to clotting and internal scarring of the veins.
In rare circumstances, a combination of ligation (tying off the abnormal vein where it connects with normal veins) and sclerotherapy is performed. More recently, endovascular laser coagulation (using heat generated by a laser fiber to damage the inside of the abnormal vein) has become available for large, dilated, relatively straight veins.
When the venous malformation includes very superficial veins in the skin or just below the skin, sclerotherapy with a weak alcohol (polidocanol) can be used as another treatment option. Polidocanol is commonly used for cosmetic spider veins and small cosmetic varicose veins in adults.
Surgical debulking of venous malformations may be performed when there is a well-demarcated cluster of dilated veins, or residual soft tissue bulk after sclerotherapy has obliterated the bulk of the abnormal veins.