Introduction
Vascular malformations are not rare, but finding an experienced physician to care for them may be difficult. This is because surgical removal may be demanding or impossible, embolization with coils requires an adequate arterial inflow, and closure with ethanol is complex and fraught with complications. Fortunately, a number of specialized multidisciplinary clinics have been formed in the United States and abroad to take care of the small number of under-served patients who harbor vascular anomalies.
Venous malformations are the most common of all vascular anomalies. They comprised 37% of BB Lee's experience at the Sungkyunkwan Vascular Malformation Clinic at the Samsung Hospital in Seoul. Of the 294 cases, 128 were in the extremities (98 in the lower). In the Vascular Anomalies Clinic of the University of California at San Francisco, 62% of patients diagnosed over 10 years of age had venous malformations.
Yakes described 36 such patients in 1994. He called attention to high-flow and low-flow malformations and pointed out that incorrect terms included hemangioma, cavernous hemangioma, venous angioma, phlebectasias, and cavernoma. Yakes used the classification system of Mulliken and Glowacki. In 1982, that system was a step forward away from the chaos of disordered terminology that dominated the 20th century. Mulliken noted that hemangiomas were true endothelial tumors that exhibited a distinct proliferative phase, which was followed by slow involution.
In 1988, a consensus conference was held in Hamburg, Germany under the direction of Stefan Belov of Sofia, Bulgaria. The conference was attended by many of the world's experts on congenital vascular malformations (CVMs), founding members of the International Society for Studies of Vascular Anomalies (ISSVA). Ultimately, this conference proposed an acceptable classification and terminology of CVMs that was properly based on embryologic information that had been accumulating over many years.
The Hamburg classification defined CVMs according to developmental arrest at various stages of embryonic life. This was somewhat modified by consensus at a meeting of these same experts in Denver in 1992. The classification singled out predominantly arterial, venous, arteriovenous shunting and lymphatic lesions in their truncular or extratruncular forms and added the anatomical forms of aplasia or obstruction, dilation, and infiltrating or limited forms. Arterial and venous forms with and without shunts were acknowledged, as were hemolymphatic types.
Extratruncular forms develop from the earliest stages of embryonic life, at the reticular stage. They have embryonic characteristics of developmental potential. This means that, when stimulated by trauma, pregnancy or surgery, they can begin to grow. They are further classified as diffuse and infiltrating, or as limited and localized.
Truncular forms develop from later stages of embryonic life and their hemodynamic impact may be severe. They are further classified as an aplasia type (obstruc tion, hypoplasia, stenosis, spur or membrane) or a dilation type (localized aneurysm, diffuse ectasia). The Hamburg classification separates vascular malformations from vascular tumors and can decrease confusion regarding these different entities.
Although the Hamburg classification provided a path away from the name-based terminology, some of these eponyms persist even though they remain imprecisely defined. As originally described, the Klippel-Trenaunay syndrome was a triad. This included a cutaneous hemangioma, varicose veins since childhood and limb hypertrophy
Gradually, as various quantities of arteriovenous shunting in these limbs were recognized, the eponym became corrupted into the Klippel-Trenaunay-Weber syndrome. Parkes Weber described "hemangiectatic hypertrophy" and included all hypertrophies of the lower limb. He included limbs not only with varices but also true arteriovenous fistulas. This introduced confusion because congenital arteriovenous fistulas and the Klippel-Trenaunay syndrome are distinctly different entities. Several authorities have described the Klippel-Trenaunay syndrome variously. At the Mayo Clinic, it was described as a limb hemangioma with over growth of bone and soft tissues in a limb with varicose veins. We favor this definition, thus separating the Klippel-Trenaunay syndrome from high-flow vascular malformations and leaving the syndrome as a venous angiodysplasia.
Probably, the Hamburg classification terminology should be used and the name-based eponyms dropped. But there is a certain historic charm in the use of eponyms, and our interpretation of the Klippel-Trenaunay syndrome is a limb with capillary vascular malformations, soft tissue and/or bony hypertrophy, and varicose veins without gross arteriovenous shunting or lymphatic/soft tissue abnormalities. Some, but not all, of these limbs have abnormal development of deep and superficial veins.
Venous malformations (angiomas) are often present at birth, although they may not be evident until later. They consist of a spongy tangle of veins, and these lesions usually vary in size (Figure 20.2). Treatment of these venous malformations is often requested for cosmetic reasons, but painful ulcerations, nerve compression and functional disability can command care.
Investigations
Following a focused physical examination, a duplex ultrasound examination can add information about blood flow, volume and velocity of a vascular malformation. If carefully done, it can identify feeding arteries and
draining veins. Magnetic resonance imaging has replaced conventional arteriography and phlebography in the initial evaluation of vascular malformations. It provides hemodynamic and anatomic information, as well as relationships with surrounding tissues and organs. Lee has found a sensitivity in excess of 97% and a specificity of 91%. It is also useful in assessment of the results of treatment. T1- and T2-weighted images have shown excellent ability to differentiate low-flow shunting from high-flow lesions. Angiography, especially catheter-directed and superselective arteriography, remains useful in pretreatment planning. Magnetic resonance imaging has a distinct limitation in differentiating between lymphatic and vascular malformations.
Personal experience
During a 30-month period, 1321 patients were investigated for venous disorders at the Vein Institute of La Jolla, CA. Fourteen (incidence: 1%) were found to have venous malformations (5 men, 9 women). The age range was 15-76 years (mean: 30.8 ± 18.6). Lesions were classified by the Hamburg system and were primarily venous, extratruncular in 12 patients and combined extratruncular and truncular in 2 patients.
Eight patients, three of them males, had manifestations of lower extremity Klippel-Trenaunay syndrome; six had only venous malformations. Eighteen of the 22 patients were treated.
All patients were studied by Doppler duplex examination. Selected lesions were chosen for helical computed tomographic studies. Magnetic resonance venography was also used to image the lesions, define the deep circulation, note connections with normal circulation, identify vessels for therapeutic access, and determine infiltration of the lesion into adjacent soft tissue.
Foam was produced by the technique of Tessari, using two syringes connected by a three-way stopcock, with the air-to-polidocanol ratio being 4 or 5 to 1. This was used at 1% or 2% concentration, specific for each patient.
The SonoSite 190 Plus duplex Doppler was used for ultrasound guidance whenever deep access was required, and to monitor progress and effects of treatment. A goal was set for each patient before treatment was begun.
The mean number of treatments was 3.6 ± 2.8 (range: 1-10). A primary goal of pain-free healing was set in patients with nonhealing, painful ulcerations or sympto matic varicose veins. This was achieved in all treated patients. Cosmetically, all of the patients were improved, and symptomatic patients were relieved of ulcers and pain.
Sclerosant foam is a satisfactory tool to use in treating venous malformations and the Klippel-Trenaunay syndrome. Use of foam sclerotherapy in this experience has proven the technique to be effective, essentially pain-free, and durable in the short term.
Discussion
Absolute ethanol sclerotherapy has been used in the treatment of vascular malformations. Its action is to denature tissue protein, precipitating protoplasm with subsequent obliteration of the vessel lumen. Its use is fraught with complications. The procedures require general anesthesia but are effective. In the Boston Children's Hospital experience, 13% of 40 patients experienced deep ulcerations, 50% had blistering and 28% had hemoglobinuria.
In order to minimize complications, sclerotherapy with liquid sclerosants has been used in the treatment of venous, lymphatic and low-flow vascular malformations. It finds a place in the treatment of small vascular malformations. Over a 20-year period ending in 1995, 157 patients were treated with liquid sclerotherapy in the Dermatology Department of the Humboldt University in Berlin, Germany. The majority of the lesions were hemangiomas and vascular malformations located in the head and neck, and 55% were in children and adolescents. One to three treatments sufficed and the results appeared durable.
Liquid sclerosants, unfortunately, become diluted and inactivated by intralesional blood. Alternatively, the use of sclerosants in microfoam form significantly improves the procedure. The foam displaces blood instead of becoming diluted, and the echogenicity of the bubbles makes them visible on ultrasound surveillance. Foam treatments, in contrast to those using ethanol, can be given on a strictly ambulatory basis.
Yamaki described the use of sclerosant foam in treating a facial vascular malformation of the cheek in a patient with a failed attempt at surgical removal.
Duplex guidance and general anesthesia were used, with the foam being produced by the Tessari technique using 1% polidocanol.
The first report of a large group of patients treated by foam sclerotherapy was that of Cabrera from Granada, Spain. The report included 50 patients, 19 with limited venous malformations, 16 with infiltrating venous malformations and 15 with Klippel-Trenaunay syndrome. Sclerotherapy was by direct injection of 0.25-4% polidocanol microfoam using ultrasound guidance. The therapy was judged to be beneficial in 92% of the patients. Amongst the 46 responders, 18 showed disappearance of treated lesions, 15 had a reduction in malformation size of more than 50% and 13 showed a reduction in malformation size of 50% or less. Of those with severe pain, 25 of 39 patients experienced total relief, and in the other 14, the pain was significantly reduced. No patient reported a major adverse event. There were 4 cases of transient skin pigmentation and 3 cases of skin necrosis.
Cabrera's group has also taken the lead in the evaluation of Klippel-Trenaunay syndrome. Their conclusion was that multidetector computed tomography and three-dimensional magnetic resonance venography are extremely helpful for the global evaluation of patients with Klippel-Trenaunay syndrome. Information regarding soft tissue and bony anatomy, as well as information about superficial and deep venous systems, may be obtained with a single examination (Figure 20.3). In examining 16 patients, persistent embryonic veins were seen in all patients. In one patient, aplasia/atresia of the whole deep venous system was revealed. Half of the patients had popliteal venous abnormalities, including aplasia (6 patients) and an aneurysm (1 patient). Other abnormalities in this group of patients included femoral vein hypoplasia in 4 patients, duplication of the femoral vein in 1 patient, and aplasia of the femoral vein in 3 patients.
Conclusions
Foam sclerotherapy holds several advantages over absolute ethanol and liquid sclerosants although, admittedly, it is nowhere near as powerful as ethanol. Neither does it carry the need for general anesthesthia or have the rate of complications of alcohol. The efficacy of a given concentration of sclerosant is greatly increased when used as foam instead of liquid. Also, a small amount of liquid can produce four to five times its volume when made into foam. It is echogenic, a significant benefit that allows foam sclerotherapy of vascular malformations to be moved into an outpatient office.
