Prof. Dirk A. Loose M.D.
Consultant Surgeon
Specialist in vascular medicine


Hardly any other vascular condition has as varied a clinical presentation as congenital vascular malformation (angiodysplasia). On the one hand, the manifestation depends on the anatomical region, and on the other hand on the localisation of the vascular abnormality. The symptoms are also dependent on these factors.

The disease manifests in the form of a pathologically altered vascular layout and circulatory system, which in most cases causes continual growth. The malformations can occur in all organs and all regions of the body– however, it is generally the arms, legs, pelvis and torso that are affected. Improper blood circulation in the extremities and organs often results in debilitating pain, swelling, skin discolouration and causes secondary diseases presenting with pain, functional limitations or even complete loss of function.

External influences have thus far not been identified as causes for the occurrence of congenital vascular malformation. Although genes and mutations could be isolated, thus proving different hereditary dispositions. (N.Limaye, M. Vikkula, Molecular and Genetic Aspects of Hemangiomas and Vascular Malformations, in: R. Mattassi, D. A. Loose, M.Vaghi, Ed.: Hemangiomas and Vascular Malformations, Springer, Italia, 2015: 21-38).

Vascular malformations occur right from the embryonic phase, probably from as early as the 6th week in the life of the embryo. In Germany, around two to four per cent of new-borns suffer from congenital vascular malformation: a comparatively high value when you consider that malformation is frequently not detected at birth. At the same time, very pronounced malformation can often be detected well before birth, i.e. in the womb. However, it can also be the case that initially hidden forms only become visible and begin to cause discomfort in later childhood or as a young adult.

It is often the case that congenital malformations are confused with so-called “stork bites”. Unlike these ‘strawberry marks’ (haemangioma), the spontaneous regression of congenital vascular malformations does not occur. However, even when a correct diagnosis is issued, in many clinics it is assumed that congenital vascular malformation cannot be treated. This is not the case, as with suitable measures, the growth of the malformed vessels can be restricted to the affected part of the body, or completely prevented. Even though not all forms of the illness can be cured, the correct treatment can have a marked positive influence on the progression of the disease. In particular, early treatment during childhood promises a good chance of success.

Colloquially, congenital vascular malformation is frequently referred to as Klippel-Trénaunay Syndrome (Riesenwuchs, published in 1900 and 1907). However, this name is much too imprecise and describes the symptoms more than the actual disease pattern. In the 1988 work, “Hamburger Klassifikation” [Hamburg Classification] (and the 2018 supplemented classification of the ISSVA: International Society for the Study of Vascular Anomalies), the disease was precisely defined as having six different types:

  • Predominantly arterial vascular defects
    • Malformation of arteries
    • Frequency: extremely rare (1 %)
    • Pain type: mainly nerve pain
    • Treatment: surgical removal of the diseased vessels (e.g. aneurysm resection and vascular reconstruction)

Truncal (late embryonic) arterial malformation in the shoulder (Arteria Axillaris)

Aneurysm resection (Removal of arterial extension) and vascular reconstruction through vein interposition graft (vascular graft)

Truncal (late embryonic) arterial malformation (Coarctatio Abdominalis). Slightly pronounced kidney artery within the course of the main artery in the chest and stomach region

Reconstruction or extension by means of synthetic or vein transplant

Truncal (late embryonic) arterial malformation Major diversion (Synthetic prosthesis) with small branches into the individual arteries

  • Predominantly venous vascular defects
    • Malformation of veins
    • Frequency: very common (65 %)
    • Pain type: sharp, cramps, tension, feeling of heaviness, overheating
    • Treatment possibilities: treatment with medication to limit the coagulation of the blood, non-surgical obliteration treatment, gradual surgical removal of the diseased vessels, thus bypassing the disturbed blood flow, removal of blood clots

Extratruncal (early embryonic) defined venous malformation in the calf. Surgical removal of the diseased vessels

Extratruncal (early embryonic) infiltrating (grown in the muscle) venous malformation. Surgical removal of the affected infiltrated tissue parts (here musculature) using the Below IV technique

Extratruncal (early embryonic) infiltrating (grown in the muscle) venous malformation on the right upper arm. Main vein present, but atrophic, it only transports a minimal amount of blood. The malformation transports the most volume.

Gradual reduction of malformation, then removal (Bypass operation), so that the existing main vein can absorb the incoming volume.

Truncal (late embryonic) venous malformation on the leg Main vein present, but atrophic. Truncal vein absorbs the main volume and causes massive congestion. Gradual reduction and then complete removal of malformation. In children the surgical technique Loose I has proven its worth in identifying the marginal vein (truncal venous malformation which runs on the outside of the leg).

Truncal (late embryonic) venous malformation on the leg Embryonic vein (a special form of the marginal vein with guide vein/Vena Femoralis missing) is under high pressure.

Surgical removal of all arteriovenous fistula (Bypass connection between artery and vein). This reduces the venous high pressure in the embryonic vein. This single draining vein must be retained at all cost.

  • Predominantly lymphatic vascular defects
    • Malformations in the lymphatic vascular system
    • Frequency: rare (3 %)
    • Pain type: congestive pain, tension, feeling of heaviness, severe pain in the case of erysipelas (bacterial infection of the upper layers of the skin and lymphatic channels)
    • Treatment: Conservative: manual lymphatic drainage, compression therapy, antibiotics in the case of erysipelas
    • Invasive: Laser surgery, obliteration of cysts, in rare cases surgery

  • Predominantly arteriovenous vascular defects
    • Improper connections between arteries and veins (arteriovenous fistulae)
    • Frequency: varying (5-15 %)
    • Pain type: painful sensitivity to heat, strong and continuous pulsing pain, pain when bearing weight, burning rest pain
    • Treatment: consistent, step-by-step closing of all arteriovenous fistulae, either by means of embolisation (artificial closure of blood vessels using a catheter technique with application e.g. if liquid plastic or mini-spiral) or also by means of the surgical closure of the arteriovenous fistulae with intraoperative ultrasound control (technique by Loose II).

Truncal (late embryonic) arteriovenous fistula.

Treatment through embolisation (Closure of diseased vessels using radiological catheter technique) or through surgical vein closure of the fistula and reconstruction of the arterial vessel with a synthetic prosthesis (see Illustration)

Truncal (late embryonic) arteriovenous malformation in the right pelvis area

Basically, an arteriovenous malformation should primarily be treated by means of embolisation therapy (Closure of diseased vessels using radiological catheter technique or by direct spraying of sclerosing agent)

Surgical closure of the feeding fistula artery as a single treatment principle is considered to be malpractice

Extratruncal (early embryonic) arteriovenous malformation in the upper thigh area. Treatment with ultrasound controlled closure of the AV fistula using the Loose II technique

If for example after embolisation therapy has been carried out (Closure of diseased vessels using radiological catheter) the smallest arteriovenous fistula that are still remaining can no longer be treated with embolisation therapy then there is the option to close these surgically using ultrasound.

Extratruncal (early embryonic) arteriovenous malformation in the upper thigh ingrown into the musculature

Surgical removal of the arteriovenous fistula in connection with the share of the affected muscle

Extratruncal (early embryonic) arteriovenous malformation in upper thigh with pressure of the great saphenous vein (Vein, which runs from foot to groin)

Closure of fistula and removal of the great saphenous vein (which is not needed) and thus normalisation of arterial and venous circulation

  • Microvascular defects
    • Malformation of capillaries/very small blood vessels (mainly in the skin or hypoderm area)
    • Frequency: rare (2 %)
    • Pain type: diffuse, localised pain
    • Treatment: local excision (surgical removal of body tissue), laser therapy

  • Combined forms
    • Mixture of the five disease types named above
    • Frequency: common (14 %)
    • Pain type: varies greatly, dependent on the predominant vessel type (venous, lymphatic, microvascular, arteriovenous)
    • Treatment: Reduction of the predominant malformed vessel types by means of sclerosing (obliteration), embolisation (artificial closure of blood vessels), laser therapy or surgery

Extratruncal (early embryonic) combined form of malformation above the temporomandibular joint. Complete removal of the malformation with preservation of the surrounding tissue structures, for example nerves

Extratruncal (early embryonic) combined form of malformation in the right wrist.

Complete removal of the malformation with preservation of the surrounding tissue structures, for example nerves