Vein Facts:

Varicose veins are a sign that there is high pressure in the veins. This is called venous insufficiency or venous hypertension.

Klippel-Trenaunay Syndrome

Written by Dallas Vein Specialists on December 16, 2019

At Dallas Vein Specialists we have had experience in the treatment of a rare congenital venous malformation, the Klippel-Trenaunay syndrome (KTS), the cause of which is a genetic mutation and not inherited. Physical changes noted at birth may lead to the diagnosis early. The syndrome involves abnormal development of blood vessels, soft tissues such as skin and muscle, bone and the lymphatics.  The malformation involves the leg and is manifested by venous varicosities of the leg, some soft tissue and or bone overgrowth of the affected leg and a cutaneous port wine stain, a red to purple birthmark of the skin . Any 2 of these 3 findings are enough to make the diagnosis. The syndrome usually involves only one leg. The varicosities are present in the affected leg, and while the port wine stain on the skin is often on the affected leg, it may occur anywhere on the body in varying size. Not everyone has all 3 signs, but there should be at least 2 of these findings in every case with often a patient demonstrating all 3.


The syndrome is the result of mutation of the PIK3CA gene. In fetal development there is a vein in the lateral leg that later in fetal development normally disappears. There appears to be evidence of remnants of this vein remaining in some patients with KTS. When this vein, the lateral marginal vein, does not entirely recede and remains in the leg the stage is set for the syndrome to develop over time. The connections of this lateral marginal vein to the deep veins, which course in the leg musculature, that remain are the source of the elevated venous pressure that leads to the massive varicosities and other signs of severe venous insufficiency including ulcerations, painful open nonhealing wounds.


The syndrome is usually progressive in that there are increasing varicosities and associated pain in the involved leg. The high venous pressure occurs from the large connections that occur between the superficial veins in the fat compartment beneath the skin and the deep veins within the leg musculature. When the leg muscles are contracted as occurs with walking, large amounts of blood rush under pressure into the superficial veins causing them to enlarge and elongate as varicosities. The venous hypertension is pro-inflammatory and over time damages the soft tissues of the lower leg where gravity dictates the pressure in the superficial veins is the greatest.


Injections of sclerosing chemicals are commonly made to close the connections to the deep veins. These are usually unsuccessful. The connections are so large and the flow so brisk that no chemical will succeed. The cause of the high venous pressure, varicosities and ulcerations are the large connections, and the best chance of eliminating them is surgery. At Dallas Vein Specialists we have been successful in substantially improving the appearance and relieving much of the distorted appearance, pain and swelling and ulcerations that accompany the malformation. There is no cure, but quality of life can be improved. Careful studies are necessary to make sure of the normal status of the deep veins before proposing surgery. Operation is aimed at open exposure of the venous connections and interrupting them permanently with surgical division and closure. Subsequent major improvements in quality of life follow.