Vascular malformations: classification, imaging and treatment

Transcription

1 Vascular malformations: classification, imaging and treatment Poster No.: C-2166 Congress: ECR 2015 Type: Educational Exhibit Authors: C. De Angelis, A. Goracci, G. Mauri, D. Poretti, V. Pedicini, F. Melchiorre, U. G. Rossi, M. Venturini, F. Sardanelli ; San 2 Donato Milanese/IT, Milan/IT Keywords: Vascular, Interventional vascular, Arteries / Aorta, CTAngiography, Ultrasound, Percutaneous, Arterial access, Embolisation, Venous access, Arteriovenous malformations, Fistula, Haemangioma DOI: /ecr2015/C-2166 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 26

2 Learning objectives The purpose of this educational exhibit is to describe the most common vascular malformations and to illustrate materials and techniques at interventional radiologist's disposal to treat them in order to achieve the best therapeutic result, outlining their advantages and limits. Page 2 of 26

3 Background Vascular malformations are structural lesions resulting from errors of vascular morphogenesis (1), histologically characterized by a single line of endothelial cells. Even if congenital, they are not always appreciable at birth. (2) (See Figure 1 and Figure 2) A multidisciplinary approach is crucial for the treatment of patients with vascular malformations. (1) Interventional radiology offers an effective, minimally invasive, treatment for these pathologies and plays a crucial role in the multidisciplinary management of such conditions. Several different techniques are available and have to be known to offer the best option to the patient according to the type (high flow, low flow or mixed lesions) of vascular malformation. (1) (2) (3) (4) (5) (7) (9) Page 3 of 26

4 Images for this section: Fig. 1: Figure 1: examples of macroscopic vascular malformations of the left hand (a), of the left gluteus (b) and of the left thoracic-abdominal wall (c). Policlinico San Donato - San Donato Milanese/IT Page 4 of 26

5 Fig. 2: Figure 2: Chart shows the mechanism for development of vascular malformations. During the fetal period, the cancellous capillary plexus differentiates into arteries, veins, and lymph channels. If fetal arterial, capillary, venous, or lymphatic components do not appropriately regress, they persist as a malformation. Anastomosis between a main artery and a main vein leads to an arteriovenous fistula. Reference n 2 Page 5 of 26

6 Findings and procedure details Classification: The differentiation of vascular malformations into high flow, low flow or mixed lesions is crucial in developing treatment strategies. (1) (2) (3) (4) (5) (7) (9) In 1982 Mulliken and Glowacki introduced a classification system rooted in the pathophysiology of these lesions (1) (11). This standard was adopted by the "International Society for the Study of Vascular Anomalies (ISSVA)" and continues to be embraced by many clinicians in current practice (1) (12). An alternative classification is the "Hamburg classification system of vascular malformations", introduced several years later. (1) (13) This classification classifies lesions first based on the prevailing vascular structures involved (arterial, venous, lymphatic or capillary), also considering arteriovenous shunting and combined vascular defects. (3) In that way, high flow vascular malformations are characterized by arterial flow and include arterial malformations, arteriovenous malformations and arteriovenous fistulae while low flow ones are characterized by venous flow, and include capillary, venous and lymphatic malformations. (3) The embryological background of the lesion is then considered for additional delineation. (1) (13) Extratruncular lesions result from developmental arrest in the early reticular embryonic stage, prior to the development of vascular trunks. Extratruncular malformations may be infiltrating and diffuse or limited and localized. (1) (13) Truncular lesions result from a defect occurring during the stage of fetal development following the reticular stage, as the vascular trunks are developing. Truncular forms develop from stenosis or obstruction of vascular trunks, with resulting hypoplasia, or dilatation of vascular trunks, which in turn may be localized or diffuse. This distinction of truncal from extratruncal may provide insight in predicting response to treatment. (1) (13) (See Figure 3, Figure 4) Imaging: Preoperative imaging is crucial to characterize the vascular malformation in order to best plan the treatment strategy. (8) Several noninvasive imaging modalities are useful in characterizing vascular malformations, contributing information about lesion size, flow characteristics and relationship to adjacent structures. (1) Conventional radiography plays a minor role, though may be valuable in defining bone and joint involvement and presence of phleboliths. (3) (7) Contrast enhanced computed tomography (CT) and CT angiography are useful in evaluating osseous involvement and phleboliths but also provide informations about enhancement, thrombosis, calcification, vascular anatomy and involvement of adjacent structures. (1) (See Figue 5, Figure 6) Page 6 of 26

7 However, ultrasonography (US) and magnetic resonance imaging (MRI) are the primary noninvasive imaging modalities used in the evaluation of vascular anomalies. US is indispensable in the evaluation of superficial vascular lesions, thanks to its high temporal and spatial resolution and ability to evaluate flow dynamics with color Doppler analysis. (1) MRI is the most valuable modality for imaging vascular anomalies due to its superior contrast resolution, ability to characterize flow dynamics, depiction of deep and adjacent structures and lack of ionizing radiation. Most information needed to characterize a vascular anomaly (such as its relationship with organs, tendons, nerves and surrounding muscles) (3) (7) can be obtained from T1-weighted, fat saturated T2-weighted and gradient echo MR sequences. Dynamic contrast-enhanced MRI can provide supporting information about flow dynamics. (See Figure 7, Figure 8) Finally, also phlebography or angiography may be performed; they are almost useful before performing the interventional procedure, because they allow the correct study of afflux and outflow vessels from and to the malformation and may guide the direct puncture of nidus. (3) (7) (See Figure 9) Indications and contraindications: In most cases, conservative treatment is recommended. Treatment should be reserved for symptomatic patients, suffering clinical complications or cosmetically disfiguring malformations that lead to unacceptable cosmetic consequences. (1) (7) Symptoms may include rapid growth, ulceration, pain, deformity/asymmetry, hemorrhage or thromboembolic complications, infections/sepsis, functional limitations or cardiac failure. (4) (7) Contraindications to treatment are close proximity of the lesion to nervous plexuses, airways or periorbital regions, broad involvement of skin or low limbs' deep veins, serious coagulopathies, cardiac malformations and chronic pulmonary embolism. (8) Treatment options: Surgery has been the standard treatment, but funcional or cosmetic problems sometimes follow surgical excision. (7) An alternative treatment option consists of an effective minimally invasive procedure operated by an interventional radiologist. Several different techniques for percutaneous treatment, such as sclerotherapy and embolization, are available, and have to be known to offer the best option to the patient, according to the type of vascular malformation. The most common treatments include sclerotherapy or embolization. Sclerosing agents include doxycycline, sodium tetradecyl sulfate (STS), ethanol, bleomycin, doxycycline and OK-432. The main embolic agents are n-bca (n-butyle-2-cyanoacrylate), Onyx (Ethylene Vinyl Alcohol Copolymer), ethanol and microspheres. Complications related to embolic agents are treatment irreversibility and the risk to paste catheter if the procedure is not sufficiently fast and the agent is not properly diluted. (See FIGURE 10) Page 7 of 26

8 Patient preparation: The procedure is performed under local or general anaesthesia; the common precautions for the use of contrast medium during angiographic procedures, CT scans or MR imaging must be considered, so the patients must be properly hydrated to prevent renal damages and previously treated with corticosteroids in case of allergy. The procedure is performed under direct puncture of the lesion or after transarterial or transvenous catheterization, based on type and localization of the malformation; catheter is usually introducted under US guidance and the procedure is performed under fluoroscopy. Drainage outflows must be previously occluded through manual compression, haemostatic lace, coil or glue; skin's color has to be controlled during the procedure, which has to be stopped in case of erythema or pallor. (9) (10) Approach to low-flow vascular malformations: 1) Venous malformations are the most frequent low-flow vascular malformations (3) (4) and result from abnormal sprouting or branching during embryonic development. (1) Two thirds of all vascular malformations are venous predominant. (1) There is female preponderance. (1) Clinically, they appear as a soft, compressible, blue/purple mass, variable with posture or with Valsalva maneuver. (3) (4) These lesions typically involve cutaneous tissues of the face, trunk and limbs, but involvement of the viscera and bones has also been described. (1) The largest may cause hypoplasia of the affected limb as compared to contralateral side, and when they develop near joints movements are painful. (3) (4) Complications that most frequently occur include intravascular coagulation (thrombosis) and development of phleboliths, calcific and may result palpable as hard and mobile masses around 1 cm. (3) (4) MRI shows venous malformations as iso-hypointense on T1-weighted images and hyperintense on T2-weighted images. (3) (7) Low flow venous malformations may be treated by compression, surgical excision or sclerosis. Sclerosing agents include STS, polidocanol and ethanol. Access to the venous malformation is generally achieved by direct puncture, utilizing ultrasound guidance. A butterfly needle is frequently utilized for more superficial malformations. Venography is then performed, and the volume of contrast administered to fill the malformation is noted. The appearance of any outflow into the deep venous structures is also noted. The malformation is emptied of as much blood as possible to increase contact of the sclerosant with the vein wall. Compression of previously visualized outflow veins is applied with tourniquets or direct pressure. Sclerosant is then injected, generaly at a volume of 50-60% of that which was noted to fill the malformations with contrast. Foam sclerotherapy is ideal for treatment of low flow vascular malformations. Foaming the sclerosant increases the surface contact of the foam micelles with the endothelium of the malformation. Depending upon the size of the malformation, additional access is obtained Page 8 of 26

9 and the process is repeated. Large truncular malformations may require coil embolization or balloon occlusion of larger outflow veins, in addition to sclerotherapy. (1) 2) Lymphatic malformations arise from abnormal development of the lymphatic system during the early phases of angiogenesis and may be diffuse, often described as lymphedema, or localized, commonly described as a lymphangioma. (1) They are typically large, spongy but non-tender masses and can affect any area of the body, even if there is a propensity for the head and neck. (1) Lymphatic malformations may be macrocystic (# 2 cm3), microcystic (< 2 cm3) or a combination of macrocystic and microcystic. (1) (3) (4) Clinically variable, they may be focal, multifocal or diffuse and infiltrative and associated to osseous distortion (elephantiasis). (3) (4) Sometimes they are blue because of the presence of venules; (3) (4) they distinguish from others lowflow vascular malformations because they are incompressible and their dimensions are always the same. (3) (4) Complications include infections and sepsis. (3) (4) They are commonly encountered in infants and children; for this reason US plays an important role in the diagnosis, staging and treatment of lymphatic malformations. Also MRI is useful in determining the type and anatomic relationships of lesion but often requires sedation or general anesthesia in children. (1) MRI shows microcystic lesions as hypointense cysts with hyperintense septa after Gadolinium. (3) (7) Sclerotherapy is the primary form of treatment of macrocystic lymphatic malformations. Lesions are punctured under US guidance and accessed with 3 to 8 French multiholed drainage catheters. The entire contents of the cysts are aspirated and then 25% to 50% fo the volume replaced with a sclerosant. The sclerosant is instilled for several hours and then aspirated. Many sclerosants can be used for the procedure (doxycycline, STS, ethanol, bleomycin and OK-432). (1) 3) Capillary malformations present as flat pink or red macules that do not involute. They result from abnormal morphogenesis of superficial dermal blood vessels, which lead to ectatic papillary demal capillaries and postcapillary venules. These lesions occur in 0,3% of newborns without prepondercance of gender. Detection typically occurs at birth, although acquired capillary malformations are rarely identified. These malformations are not treated by interventional radiologist because superficial; in fact, they're pertaining to plastic surgery. (1) Approach to high flow vascular malformations: High flow vascular malformations exhibit variable presentation dependent on location. Superficial lesions may present as a warm painless mass with palpable bruit and associated dilated veins; skin erosion and bleeding is possible. Deeper lesions may present with steal phenomena as the malformation deprives blood flow from downstream structures. (1) 1) Arteriovenous malformations, often extratruncular, are the most frequent high-flow vascular malformations, and consist of a low resistance nidus recruiting blood supply Page 9 of 26

10 from numerous regional inflow arteries and draining by multiple outflow veins. (1) (3) (4) (5) Clinically, they present as painless, mobile, compressible and pulsating masses; dimensions don't vary with posture (but may vary with age, in particular they are related to hormonal and stress factors) and they may appear blue or red. (3) (4) (5) There have been identified four developmental stages, related to different complications: a quiescent phase, an expansion phase, a destruction phase and, finally, a decompensation (high output cardiac failure) phase. (1) (6) The goal in the treatment of high flow arteriovenous vascular malformations is eradication of the nidus, which is best accomplished with a liquid embolic agent that penetrates the feeding vessels into the nidus. (1) Particulate agents, such as polyvinyl alcohol (PVA) may be used independently or in conjunction with liquid embolic agents. Particulate agents do not generally provide complete occlusion, and recanalization may occur. (1) A commonly employed embolic agent is n-butyl cyanoacrylate ("glue"), which is a non-adherent liquid in a nonionic environment that rapidly polymerizes in an ionic environment. Polymerization rate is decreased by mixing with increasing volumes of Lipiodol, permitting pregressively distal penetration. Selecting the ideal ratio of n-bca/lipiodol permits polymerization to occur within the nidus of the arteriovenous malformations rather than the feeding artery. (1) An alternative to n-bca as a liquid embolic agent is Onyx. Distal microcatheter placement is essential. When using this material, a "plug" of Onyx is first formed around the tip of the microcatheter, preventing retrograde flow, and then the agent is forced in the direction of the nidus. (1) Finally, ethanol is an extremely effective alternative liquid agent, which causes protein denaturation and endothelial cell destruction. (1) The treatment success rate of using ethanol in arteriovenous malformations has been reported up to 68%. Its efficacy decreases with decreasing concentration, making it difficult to mix with contrast agents and still achieve the same result. It has a greater tendency for peripheral penetration and a higher incidence of non-target injury such as skin necrosis, nerve injury and related complications. Using a balloon occlusion catheter during ethanol delivery may decrease the incidence of complications. Acute pulmonary hypertension, right heart strain, and sudden death during the administration of alcohol have been reported, urging careful monitoring of pulmonary arterial pressures during procedures involving alcohol sclerosis. (1) (See Figure 11, Figure 12, Figure 13, Figure 14, Figure 15) 2) Macrofistulas malformations are truncular malformations, and consist of single or multiple arteries directly communicating with outflow veins without an interposed high resistance capillary system. (1) They are treated by coil occlusion of the fistula at the distal arterial end of the communication (accurate oversizing of the coils is essential to eliminate systemic embolization of the coil). In addition to coils, occlusion devices may be considered (such as the Amplatzer occlude device). (1) Page 10 of 26

11 Images for this section: Fig. 3: Figure 3: ISSVA classification of vascular malformations. Reference n 12 Page 11 of 26

12 Fig. 4: Figure 4: The Hamburg classification of vascular malformations. Reference n 13 Page 12 of 26

13 Fig. 5: Figure 5: 5a Patient showing a voluminous arteriovenous malformation at left thoracic and abdominal wall. 5b Posterior-anterior chest radiogram of the same patient, shows the voluminous malformation at left thoracic wall; yellow arrows refers to metallic elements inserted during previous treatments of the malformation. 5c-d arteriography and CT scan of the same patient. Policlinico San Donato - San Donato Milanese/IT Page 13 of 26

14 Fig. 6: Figure 6: Axial (a), coronal (b) and sagittal (c) CT scans, after injection of iv iodate contrast agent, of the same patient of figure 5, showing the voluminous arteriovenous malformation (*) at left thoracic and abdominal wall. Policlinico San Donato - San Donato Milanese/IT Page 14 of 26

15 Fig. 7: Figure 7: shows axial RM scans on T2 (a), T2FS (b) and T1 weighted images indicating an artero-venous malformation of the pelvic region, mainly on the right. We can recognise that fat tissue (*) is not homogeneous in the right inferior gluteus and at thigh's root on the posterior side; also muscles of the posterior region of the thigh are not homogeneous and this is related to the presence of the VM. Policlinico San Donato - San Donato Milanese/IT Page 15 of 26

16 Fig. 8: Figure 8: shows coronal (a) and axial (b) T2-weighted. Yellow arrows indicate ferromagnetic artifacts as a result of prior treatments: metallic spirals were introducted on the right side of the pelvic floor. Policlinico San Donato - San Donato Milanese/IT Page 16 of 26

17 Fig. 9: Figure 9: arteriography with selective catheterization (red arrow) of right internal iliac artery to study an arteriovenous pelvic malformation (*). Policlinico San Donato - San Donato Milanese/IT Page 17 of 26

18 Fig. 10: Figure 10: Treatment of vascular malformation. (a) Diagram shows a simple vascular malformation that consists of one feeding artery, the nidus, and one drainage vein. For this type of lesion, sclerotherapy with percutaneously administered liquid sclerosant is indicated. (b) Diagram shows a vascular malformation with several feeding arteries and drainage veins. For this type of lesion, sclerotherapy begins with a flowcontrol procedure (the drainage vein is occluded by means of a balloon catheter with or without use of coils or n-butyl cyanoacrylate [NBCA] to decrease the number of drainage veins) to achieve sclerosant stasis. Additional sclerotherapy to the nidus is then performed. (c) Diagram shows a vascular malformation with several drainage veins and feeding arteries, one of which was embolized. This is an ineffective procedure that makes the latent feeding arteries apparent. The nidus flow volume usually increases, and clinical symptoms worsen. As with embolization of the feeding artery, coil embolization of the drainage vessel alone is not sufficient treatment. Without ablation of the nidus, a good outcome cannot be expected. Reference n 7 Page 18 of 26

19 Fig. 11: Figure 11: (a) arteriovenous vascular malformation of the left foot; the image shows an example of direct puncture of VM under fluoroscopic guidance; (b) arteriovenous malformation of gluteus, thigh's root and pelvic floor on the right; yellow arrow shows the site of access during arteriography, which was transfemoral: the malformation is composed of curvy, ectasic arteries with many artero-venous shunts; part of he malformations is also feeded by branches of the left internal iliac artery. Policlinico San Donato - San Donato Milanese/IT Page 19 of 26

20 Fig. 12: Figure 12: arteriovenous vascular malformation of the left foot; images a-b-c show treatment through direct puncture of many points of VM at internal plantar under angiographic guidance with microparticles (Glubran); arteriographic study of the region of the left foot, location of the VMthrough anterograd of the left common femoral pucture (d-e): there are multiple pathologic areas, mainly extended at internal side of the foot, characterized by a wide nidus and wide venous drainages; frontal (d) and lateral (e) scans of VM. Image f shows the treatment with devascularization of a part of the VM and consequent its reduction. Policlinico San Donato - San Donato Milanese/IT Page 20 of 26

21 Fig. 13: Figure 13: arteriovenous malformation of gluteus, thigh's root and pelvic floor on the right; selective catheterization of the right internal iliac artery (a, yellow arrow); embolization with a radiotrasparent fluid as embolic agent under fluoroscopic guidance (b, yellow arrow). Policlinico San Donato - San Donato Milanese/IT Page 21 of 26

22 Fig. 14: Figure 14: arteriovenous malformation of the thigh's root. Arteriography of the vascular malformation (a); yellow arrow shows a spiral, outcome of a former therapeutic procedure; check after embolization (b). Policlinico San Donato - San Donato Milanese/IT Page 22 of 26

23 Fig. 15: Figure 15: voluminous arteriovenous vascular malformation of right thigh. Arteriography of the right tight (a); yellow arrow shows selective catheterization of an arterial branch of the malformation (b); check after embolization (c). Policlinico San Donato - San Donato Milanese/IT Page 23 of 26

24 Conclusion Interventional radiology plays a crucial role in the management of patients affected by vascular malformations. A multidisciplinary approach is crucial in the treatment of patients with these pathologies. Page 24 of 26

25 References 1)Nosher JL, Murillo PG, Liszewski M, Gendel V, E Gribbin C. Vascular anomalies: A pictorial review of nomenclature, diagnosis and treatment. World Radiol 2014 September 28; 6(9): ) Nozaki T, Nosaka S, Miyazaki O, et al. Syndromes associated with vascular tumors and malformations: a pictorial review. Radiographics 2013 Jul-Aug;33(4):12A. 3) Colletti G, Valassina D, Bertossi D, et al. Contemporary management of vascular malformations. J Oral Maxillofac Surg Mar;72(3): ) Burrows PE. Endovascular treatment of slow-flow vascular malformations. Tech Vasc Interv Radiol Mar;16(1): ) Rosen RJ, Nassiri N, Drury JE. Interventional management of high-flow vascular malformations. Tech Vasc Interv Radiol Mar;16(1): ) Schobinger R. Proceedings of International Society for the Study of Vascular Anomalies Congress Rome, Italy, June 23-26, ) Hyodoh H, Hori M, Akiba H, et al. Peripheral vascular malformations: imaging, treatment approaches, and therapeutic issues. Radiographics 2005;25 Suppl 1:S ) Feoktistov I, Ryzhov S, Zhong H, et al. Hypoxia modulates adenosine receptors in human endothelial and smooth muscle cells toward an A2B angiogenic phenotype. Hypertension 2004; 44: ) Alomari A, Dubois J. Interventional management of vascular malformations. Tech Vasc Interv Page 25 of 26

26 Radiol Mar; 14(1): ) Odeyinde SO, Kangesu L, Badran M. Sclerotherapy for vascular malformations: complications and a review of techniques to avoid them. J Plast Reconstr Aesthet Surg Feb;66(2): ) Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants and children: a classification based on endothelial characteristics. Plast Reconstr Surg 1982; 69: ) From: 13) Belov S. Anatomopathological classification of congenital vascular defects. Semin Vasc Surg 1993; 6: Page 26 of 26