IV. Venous malformation

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Arteriovenous malformations and Stewart-Bluefarb syndrome
Alicia O’Connor, Australia

The evolution of the classification of vascular anomalies and the pathophysiology, evolution, and types of arteriovenous malformations were presented, the seminar concluded with an introduction to the 2015 Yakes arteriovenous malformation classification.1

Stewart-Bluefarb syndrome, a rare angioproliferative disorder that was first described in 1967, is characterized by an acroangiodermatitis that is associated with an underlying arteriovenous shunt. Acroangiodermatitis is a benign, uncommon angioproliferative disease characterized by violaceous macules, papules, or plaques on the dorsum of the feet. The malleolus pathogenesis is poorly understood, but it may be the result of an angiogenesis response to high perfusion rates.

A series of 5 patients was presented, where all underlying arteriovenous communications were initially diagnosed on duplex ultrasound and confirmed with magnetic resonance angiography. Congenital arteriovenous malformations were found in 4 patients, while 1 patient was diagnosed with a postthrombotic arteriovenous fistula. In 1 female and 2 male patients, the diagnosis was delayed as the acroangiodermatitis closely resembled other conditions. Management included observation and intervention using a variety of techniques, including percutaneous or transcatheter embolization, endovenous laser ablation, radiofrequency ablation, and ultrasound-guided foam sclerotherapy.

In conclusion, the presented case series highlights the challenges involved in the diagnosis and management of the Stewart-Bluefarb syndrome. Given the local and systemic sequelae of high-flow shunts, correct diagnosis and early detection of the underlying arteriovenous abnormalities are crucial for the long-term management of these patients and for preventing the associated complications.

1. Yakes WF. Yake’s AVM classification system [abstract 521]. J Vasc Interv Radiol. 2015;26:S224.

Klippel-Trenaunay syndrome: treatment with endovenous laser therapy
Roberto Simkim, Argentina

In this presentation, the management of Klipplel-Trenaunay syndrome was discussed. Intraoperatory ultrasound-guided endovenous laser therapy was performed in 11 patients with Klipplel-Trenaunay syndrome (3 cases treated with a 980 nm laser diode and 8 cases with a 1470 nm laser diode). In all cases, a preoperatory lower limb arteriography was performed. Previously, a person with Klipplel-Trenaunay syndrome who had been treated with a skeletozation technique was shown to have recurrence of the microarteriovenous fistulae 18 years later, as demonstratedby digital arteriography. Based on lower-limb arteriography, in the present cases where endovenous laser therapy was performed, there was a decrease in the microarteriovenous fistulae, showing that endovenous laser therapy could decrease the microarteriovenous fistulae present in patients with Klipplel-Trenaunay syndrome.

Regional segmentary skeletozation is a good technique that reduces the arteriovenous fistulae present in the lower limbs; however, the recurrence of varicose veins in these cases can be ≈30%. Endovenous laser therapy is a good technology for the treatment of varicose vein recurrences, which could apparently decrease the microarteriovenous fistulae in patients with Klipplel-Trenaunay syndrome.

Sclerotherapy in venous malformation
Yong Soo Do, Korea

Venous malformations represent 37.7% of the congenital vascular malformations. The symptoms include pain, presence of a mass in the body, and swelling due to venous hypertension. Consumption coagulopathy, cosmetic deformity, functional impairment (combined with abnormal bone growth), and pulmonary embolisms can be observed. Venous malformations, with combined abnormal bone growth, occurs in about 5% of cases. Abnormal bone growth may be due to hypertrophy (4%) or hypotrophy (1%). In cases of bone hypertrophy, there is an increase in the vascularization of the growth plate due to high oxygen tension and elevated temperature. In bone hypotrophy, there is a pressure reduction on the bone’s metaphysis due to venous hypoplasia. Venous malformations may cause a length discrepancy of more than 2 cm between both legs, which may be accompanied by pelvis tilting and spine lordosis.

Venous malformations are diagnosed by physical examination (soft compressible, palpable mass, and phleboliths), radioisotope imaging (Tc-99m labeled red blood cells), and magnetic resonance imaging (high-signal intensity lesion on T2-weighted imaging with fat suppression). Most venous malformations remain stable and quiescent without spontaneous regression. Often venous malformations grow slowly, but a growth spurt can occur at puberty or during the adolescent period. A second expansion can be observed around pregnancy.

The treatment consists of compression stockings, surgical resection, sclerotherapy, and low-molecular-weight heparin for consumption coagulopathy. The surgical treatment of venous malformations is limited with high recurrences, and the lesions can expand to a size that is larger than the initial size of the venous malformation and reapportion is almost impossible. Preoperative embolosclerotherapy is often performed to reduce intraoperative hemorrhages. Better results are observed when using sclerotherapy with polidocanol or sodium tetradecyl sulphate, which improves symptom relief in 74% of cases. The complication rate is around 10% to 30% with some injury (blisters and necrosis), nerve damage (transient or permanent), deep vein thrombosis, and fatal cardiac arrest.

In conclusion, ethanol or foam sclerotherapy with polidocanol or sodium tetradecyl sulphate are effective treatments for symptomatic localized venous malformations, with an acceptable rate of minor complications, but the patients need to be carefully selected.

Clinical course and management of vascular anomalies
Kurosh Parsi, Australia

The vascular anomalies are classified in vascular tumors and congenital vascular malformations. The diagnosis can be difficult and may require various imaging modalities (ultrasound and magnetic resonance). Hemangiomas are the most common vascular tumors, which can be either congenital or appear during infancy. The most common vascular tumor is the hemangioma in infancy (HOI), which occurs in approximately 10% of Caucasians and more frequently in females. HOI has three stages, initial proliferation and growth, a rest stage, and involution. HOIs are selflimited and benign. Vascular malformations that are present at birth do not involute.

The modified Hamburg classification is the most utilized classification system and this classification sorts the congenital venous malformations into extratruncular and truncular. Truncular malformations are more hemodynamically significant than extratruncular malformations. Extratruncular malformations (previously called angioma or angiomatous lesions) are present as lesions that are more primitive and occur at earlier stages of vasculogenesis. Truncular malformations arise from preexisting vascular structures in later stages of vasculogenesis and can present as ectasia, hypoplasia, agenesis, obstruction, or aneurysm of mature vessels (eg, popliteal vein aneurysm, persistent embryonic marginal vein, and embryonic sciatic vein).

Correct diagnosis is the most important part of managing venous malformations. Diagnosis starts by obtaining a detailed history, performing a clinical examination, and determining the presence of the lesion at birth (growth proportionate or disproportionate to the child’s growth and family history). The doctor should examine the lesion and the contralateral normal side to look for asymmetry. Ultrasound imaging and magnetic resonance imaging are mandatory for the diagnosis. B-mode ultrasound tests for compressibility (venous malformation) or noncompressibility (lymphatic malformation, arteriovenous malformation, and thrombosed or treated venous malformation). Lymphatic malformations show no flow on Doppler flow analysis, venous malformations show low or no flow (if thrombosed or sclerosed), and arteriovenous malformations show slow resistance, high diastolic flow, turbulence, and aliasing at the nidus. Magnetic resonance imaging is mandatory to evaluate the extension of the lesion and may eventually be complemented by using computed tomography angiography. When appropriate, a baseline evaluation may include whole-body blood pool scintigraphy, magnetic resonance imaging, and a biopsy of individual lesions.

It is essential to assess the extent, severity, and progression of the lesion prior to treatment. Early aggressive treatment may be required to prevent life- or limbthreatening complications. It is essential to ensure that the benefits from the intervention exceed the morbidity from the treatment since ill-planned interventions can stimulate explosive growth of the lesion.

Arteriovenous malformations and venous malformations are as different as apples and oranges
Byung Boong Lee, USA

Arteriovenous malformations and venous malformations are two different types of congenital vascular malformations. Congenital vascular malformations are a group of various birth defects developed anywhere throughout the entire peripheral vascular system, following the developmental arrest during various stages of embryogenesis. Therefore, congenital vascular malformations are not one disease entity, but a mixture of various defects with different characteristics and behaviors, often affecting more than one vascular system–capillary, arterial, venous, or lymphatic system.

Arteriovenous malformations result from a defective development that affects both the arterial and venous systems, but venous malformations represent a defective development that only affects the venous system, with no arterial involvement. Arteriovenous and venous malformations have entirely different clinical courses with different prognoses. Subsequently, the management principle and strategy of both conditions are fundamentally different, with both being as different as apples and oranges, although both are classified together as a congenital venous malformation.

Arteriovenous malformations are relatively rare among various congenital venous malformations, but they are the most destructive of all congenital venous malformation lesions. They have the highest risk of progression with a more destructive potency due to complicated central, peripheral, and local hemodynamic impacts on the entire cardiovascular system (arterial, venous, and lymphatic). In general, an early approach to the treatment of all arteriovenous malformation lesions, either macro- or microarteriovenous shunting, is mandated. Whenever and wherever possible, it is necessary to reduce the impact and consequence of the arteriovenous malformation lesion.

Aggressive control of the nidus of the lesion itself is essential to prevent recurrence and/or a first deterioration of the arteriovenous malformation lesion and to minimize the complicated hemodynamic consequences. Treating the arteriovenous malformation with a strategy to stop the feeding artery and leave the nidus intact made the condition worse, provoking more aggressive neovascular recruitment to the primitive lesion without exception.

On the contrary, venous malformations seldom become a limb- or life-threatening condition, except in a few cases involving the structure of vital organs. Venous malformations are the most common congenital venous malformations and the majority exists as an independent lesion that has a relatively benign course unless other congenital venous malformations are present. Therefore, not all (extratruncular) venous malformation lesions are indicated for therapy and they should be treated according to a discriminating selection based on new guidelines and new treatments modalities.