Minimally Invasive Tumor Therapy (MITT)

Department of Radiology, Charité – Universitätsmedizin Berlin

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References

  1. Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants and children: a classification based on endothelial characteristics. Plastic and reconstructive surgery. 1982;69(3):412-22.
  2. Nozaki T, Matsusako M, Mimura H, Osuga K, Matsui M, Eto H, et al. Imaging of vascular tumors with an emphasis on ISSVA classification. Japanese journal of radiology. 2013;31(12):775-85.
  3. Hyodoh H, Hori M, Akiba H, Tamakawa M, Hyodoh K, Hareyama M. Peripheral vascular malformations: imaging, treatment approaches, and therapeutic issues. Radiographics. 2005;25 Suppl 1:S159-71.
  4. Donnelly LF, Adams DM, Bisset GS, 3rd. Vascular malformations and hemangiomas: a practical approach in a multidisciplinary clinic. AJR Am J Roentgenol. 2000;174(3):597-608.
  5. Burrows PE. Hemangiomas and vascular malformations. Canadian Association of Radiologists journal = Journal l'Association canadienne des radiologistes. 1995;46(2):143.
  6. Lee BB, Baumgartner I, Berlien HP, Bianchini G, Burrows P, Do YS, et al. Consensus Document of the International Union of Angiology (IUA)-2013. Current concept on the management of arterio-venous management. International angiology : a journal of the International Union of Angiology. 2013;32(1):9-36.
  7. Burrows PE, Mulliken JB, Fellows KE, Strand RD. Childhood hemangiomas and vascular malformations: angiographic differentiation. AJR Am J Roentgenol. 1983;141(3):483-8.

Interventional Treatment of Blood Vessel Defects or Arteriovenous Malformations (AVM)

 

Vascular anomalies are a large heterogeneous group of blood vessel defects or abnormal clusters of blood vessels. Two major groups of vascular anomalies are distinguished: vascular tumors (hemangiomas) and abnormal connections between blood vessels (vascular malformations) (1). The differences between hemangiomas and vascular malformations are summarized in Table 1. In addition, there are mixed types with features of both hemangiomas and malformations.

 

Table 1:

Differences between hemangiomas and vascular malformations (from (4))

 

 

 

 

 

 

 

 

 

 

Vascular malformations are benign vascular lesions that occur during fetal development. They are present at birth but may not be visible or cause symptoms (2). These malformations arise from arteries, capillaries, veins, or lymphatic vessels (Table 2). Two groups of vascular malformations are distinguished on the basis of blood flow velocity in the abnormal vessel connections: high-flow malformations (fast-flowing blood) and low-flow malformations (slow-flowing blood) (Table 3).

 

Table 2:

Simplified ISSVA classification of vascular anomalies

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 3:

High-flow und low-flow malformations according to Burrows & Mulliken 1983 (7)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

High-flow vascular malformations involve the arterial or capillary vascular system, while low-flow malformations are connected to the venous or lymphatic vascular system (Figure 1).

 

Figure 1: A An infantile hemangioma consists of a solid cellular mass with an organized, acinar pattern of arterial supply and drainage into dilated regional veins. B An arteriovenous fistula is a focal macroscopic connection between an artery and a vein, which is typically dilated. C An arteriovenous malformation typically consists of a nidus or network of abnormal vascular channels with feeding arteries and draining veins. D A venous malformation is a postcapillary lesion composed of abnormally shaped, dilated venous channels. Major conducting veins can be involved. E A lymphatic malformation is composed of fluid-filled spaces or channels lined with lymphatic endothelium. (From (5)).

 

Treatment is different for high-flow and low-flow vascular malformations (Table 3). In addition, the treatment depends on the site and severity of the malformation. Vascular malformations can occur anywhere in the body (such as the brain, skin, lungs, kidneys, or liver). The site determines the patient’s signs and symptoms and hence the type of treatment that is likely to be effective.

 

Vascular malformations should be treated when they cause symptoms. The reasons that make treatment necessary or advisable (absolute and relative indications) are summarized in Table 4. Treatment options include sclerotherapy, embolization, surgical removal, laser coagulation, and manual compression (3).

 

Table 4:

Absolute and relative indications for the treatment of vascular malformations

 

 

 

 

 

 

 

 

 

 

 

The treatments performed by interventional radiologists are briefly described below.

 

Sclerotherapy

 

Sclerotherapy is the direct local injection of an irritating agent through a needle that is advanced through the skin into the abnormal vessel cluster. It aims at destroying the innermost lining of the vessel wall (endothelium) to induce formation of blood clots (thrombosis), thus stopping blood flow through the abnormal vessels. Different substances can be used for sclerotherapy of vascular malformations. Common sclerosing agents are highly concentrated alcohol, alcohol gel (Sclerogel), lauromacrogol (Aethoxysclerol) foam, and sodium tetradecyl sulfate (STS, Fibro-Vein) foam (Figure 3). Lymphatic malformations can also be treated using doxycycline or picibanil (OK-432). After the procedure, the treated malformation should be compressed by a bandage. Sclerotherapy is typically used to treat malformations in which venous outflow is the main problem. In these cases, the sclerosing agent is injected directly into the vein.

 

Embolization

 

Transarterial embolization is mainly used to treat high-flow malformations with an arterial feeder (Figure 2). In such cases, arterial blood flow to the vascular anomaly can be reduced or stopped by means of small metal devices or embolic (clotting) agents. Metal devices like coils or plugs are deployed in the feeding artery to block blood flow to the malformation. Embolic agents for occlusion of arterial feeders include highly concentrated alcohol, ethanol gel (Sclerogel), small plastic particles, tissue glue (Histoacryl), and liquid embolic agents (Onyx) (Figure 4).

 

 

 

Figure 2: Angiographic classification of arteriovenous malformations (AVM): Type I (arteriovenous fistula): shunting (S) of typically three separate arteries (A) and a single draining vein (V). Type II (arteriolovenous fistula): shunting (S) of multiple arterioles (A) and a draining vein (V). Type III (arteriolovenous fistula): multiple shunts (S) between arterioles (A) and venules (V) (1, 6).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For optimal treatment of a complex malformation, it may be advisable to combine sclerotherapy and transarterial embolization (Figure 5). In most cases, it takes more than one procedure to completely eliminate a vascular malformation. Interventional treatment of vascular malformations may be painful, which is why we typically use general anesthesia for these procedures.

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  • Contact:

Minimally Invasive Tumor Therapy (MITT)

Charité, Campus Virchow-Klinikum

Department of Radiology

Augustenburger Platz 1

13353 Berlin, Germany

Phone: +49 (0)30/450-557309

Fax: +49 (0)30/450-557947

minimal-invasive-ambulanz@charite.de oder mia@charite.de

 

Case Examples

 

 

Figure 3: Arteriovenous malformation of the fourth toe of the right foot. The leftmost arterial angiogram shows a marked vascular anomaly. The next angiogram shows the thin needle that is directly inserted into the area of increased blood flow at the root of the fourth toe. The malformation is embolized by injection of alcohol gel (Sclerogel). The final angiogram, obtained after sclerotherapy, shows markedly reduced blood flow. The patient’s symptoms improved after treatment.

 

Figure 4: Pulmonary arteriovenous malformation. In this case, the shunt in the lung was closed by deploying 2 vascular plugs, which were introduced through the pulmonary artery.

 

Figure 5: Combined transvenous sclerotherapy with highly concentrated alcohol gel (Sclerogel) and transarterial embolization with tissue glue (Onyx) in 2 treatment sessions. The upper row of images shows the malformation in the area of the left shoulder before embolization. The malformation had a mass effect and caused pain. The second row of images shows the situation after the first treatment session: markedly reduced blood flow at the site of the lesion is apparent. The bottom row of images shows the outcome after the second treatment session of the combined approach used in this patient.

Vascular malformations

  • Consist of dysplastic blood vessels
  • Present at birth
  • Growth proportional to child
  • No regression/shrinkage

Relative

  • Pain
  • Debilitating pain
  • Functional problems
  • Severe cosmetic deformity
  • High risk of complications
  • Lymphatic leakage
  • Abnormal bone growth due to malformation

Hemangiomas

  • Show cellular proliferation
  • Small or absent at birth
  • Rapid growth in early childhood
  • Involution/Regression in late childhood

Absolute

  • Bleeding
  • Heart failure due to arteriovenous shunt volume
  • Ischemia
  • Chronic venous ischemia
  • Malformation disturbs vital functions
  • Compression or obstruction of important structures

Vascular tumors

Vascular malformations (clusters of abnormal vessels)

Simple

 

Combined

Flow velocity

Hemangioma

Capillary

Venous

Lymphatic

Lymphaticovenous malformation (LVM)

Capillary lymphaticovenous malformation

Slow

Hemangioendothelioma

Angioma

Arterial/Arteriovenous malformation (AVM)

Capillary arteriovenous malformation

Fast

A

Malformation

High-flow

Low-flow

Definition

Involves the arterial or capillary vascular system

Involves the venous or lymphatic vascular system

Examples

Arteriovenous fistula

Arteriovenous malformation

Venous malformation

Lymphatic malformation

Capillary malformation

Combined malformation

Treatment

Transarterial embolization

Sclerotherapy

B

C

D

E