Vascular Surgery for Arteriovenous Malformations

Updated: Sep 09, 2016
  • Author: Allison Leigh Speer, MD; Chief Editor: Vincent Lopez Rowe, MD  more...
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Overview

Background

Vascular anomalies are among the most common congenital abnormalities in infants and children. Historically, their treatment has been impeded by confusing terminology and imprecise classification. Lesions were named with descriptive terms (eg, strawberry hemangioma or port-wine stain) or histopathologic terms (eg, capillary hemangioma, cavernous hemangioma, or lymphangioma). Although some vascular anomalies may appear similar, their biologic behavior differs markedly; therefore, treatment should be based on a proper classification system. [1, 2]

Classification

Classification of vascular anomalies is based on the landmark 1982 paper by Mulliken and Glowacki, which proposed a simplified categorization of these anomalies that was based on biologic activity. [3] As a result, the following two main types of vascular anomalies are generally recognized:

  • Vascular tumors
  • Vascular malformations

Differentiating between these two types of anomalies is essential because their treatment is quite different. The management of vascular anomalies is a dynamic and rapidly developing subspecialty, which requires interdisciplinary care and collaboration.

During its 1996 workshop, the International Society for the Study of Vascular Anomalies (ISSVA) adopted a classification system designed to provide a common language for guiding treatment. It was based on Mulliken and Glowacki’s biologic study but also further distinguished vascular malformations according to hemodynamics and predominant anomalous channels (see Table 1 below). [4, 5, 6, 7]

Table 1. ISSVA 1996 Classification of Vascular Anomalies (Open Table in a new window)

Vascular Tumors Vascular Malformations
Infantile hemangiomas



Congenital hemangiomas



Rapidly involuting congenital hemangioma (RICH)



Noninvoluting congenital hemangioma (NICH)



Tufted angioma (± Kasabach-Merritt syndrome)



Kaposiform hemangioendothelioma (± Kasabach-Merritt syndrome)



Spindle cell hemangioendothelioma



Other, rare hemangioendotheliomas (eg, epithelioid, composite, retiform, polymorphous, Dabska tumor, lymphangioendotheliomatosis)



Dermatologic acquired vascular tumors (eg, pyogenic granuloma, targetoid hemangioma, glomeruloid hemangioma, microvenular hemangioma)



Slow-flow vascular malformations



Capillary malformation (CM)



  • Port-wine stain
  • Telangiectasia
  • Angiokeratoma
Venous malformation (VM)



  • Common sporadic VM
  • Bean syndrome
  • Familial cutaneous and mucosal venous malformation (VMCM)
  • Glomuvenous malformation (GVM)
  • Maffucci syndrome
Lymphatic malformation (LM)



  Fast-flow vascular malformations



Arterial malformation (AM)



Arteriovenous fistula (AVF)



Arteriovenous malformation (AVM)



 



  Complex-combined vascular malformations



CVM



CLM



LVM



CLVM



AVM-LM



CM-AVM



C=capillary, V=venous, L=lymphatic, A=arterial, M=malformation, F=fistula

At its 20th workshop in 2014, the ISSVA approved a revised classification (see Table 2 below). [8]

Table 2. ISSVA 2014 Classification of Vascular Anomalies (Open Table in a new window)

Vascular Tumors Vascular Malformations
Benign vascular tumors



Infantile hemangioma/hemangioma of infancy



Congenital hemangioma



  • Rapidly involuting (RICH)
  • Noninvoluting (NICH)
  • Partially involuting (PICH)
Tufted angioma



Spindle-cell angioma



Epithelioid angioma



Pyogenic granuloma



Others



Simple vascular malformations



Capillary malformation (CM)



  • Cutaneous/mucosal CM (port-wine stain)
  • Telangiectasia
  • Cutis marmorata telangiectatica congenita (CMTC)
  • Nevus simplex/Salmon patch
  • Others
Lymphatic malformation (LM)



  • Common/cystic LM
  • Generalized lymphatic anomaly (GLA)
  • LM in Gorham-Stout disease
  • Channel-type LM
  • Primary lymphedema
  • Others
Venous malformation (VM)



  • Common VM
  • Familial VM cutaneomucosal (VMCM)
  • Blue rubber bleb nevus (Bean) syndrome VM
  • Glomuvenous malformation (GVM)
  • Cerebral cavernous malformation (CCM)
  • Others
Arteriovenous malformation (AVM)



  • Sporadic
  • In hereditary hemorrhagic telangiectasia (HHT)
  • In CM-AVM
  • Others
Arteriovenous fistula (AVF)



  • Sporadic
  • In HHT
  • In CM-AVM
  • Others
Locally aggressive or borderline vascular tumors



Kaposiform hemangioendothelioma



Retiform hemangioendothelioma



Papillary intralymphatic angioendothelioma, Dabska tumor



Composite hemangioendothelioma



Kaposi sarcoma



Others



Combined vascular malformations



CM + VM = CVM



CM + LM = CLM



CM + AVM = CAVM



LM + VM = LVM



CM + LM + VM = CLVM



CM + VM + AVM = CVAVM



CM + LM + VM + AVM = CLVAVM



Malignant vascular tumors



Angiosarcoma



Epithelioid hemangioendothelioma



Others



Anomalies of major named vessels (channel-type or truncal vascular malformations)



Affecting



  • Lymphatics
  • Veins
  • Arteries
Anomalies of



  • Origin
  • Course
  • Number
  • Length
  • Diameter
  • Valves
  • Communication (AVF)
  • Persistence (of e,bryonal vessel)
  Vascular malformations associated with other anomalies



Klippel-Trenaunay syndrome



Parkes Weber syndrome



Servelle-Martorell syndrome



Sturge-Weber syndrome



Limb CM + congenital nonprogressive limb hypertrophy



Maffucci syndrome



Macrocephaly-CM



Microcephaly-CM



CLOVES syndrome



Proteus syndrome



Bannayan-Riley-Ruvalcaba syndrome



C=capillary, V=venous, L=lymphatic, A=arterial, M=malformation, F=fistula.  

A few vascular anomalies remain provisionally unclassified. [8] Additional information is available on the ISSVA Web site.

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Pathophysiology

The pathogenesis of AVMs is not well understood [9] but is thought to involve abnormal vasculogenesis. Multiple biologic studies since 1982 have demonstrated clear differences between vascular tumors (hemangiomas) and vascular malformations. Some have hypothesized that infantile hemangiomas result from excess angiogenesis, whereas vascular malformations are due to errors in vessel remodeling. [10] Although some vascular malformations thicken, expand, or multiply with time, whether true angiogenesis occurs is unclear.

Marler et al suggested that vascular malformations may be angiogenesis-dependent disorders. They found that urinary high-molecular-weight matrix metalloproteinases (hMW MMPs) and basic fibroblast growth factor (bFGF) levels are elevated in vascular tumors and some vascular malformations (eg, lymphatic malformations [LMs], lymphaticovenous malformations [LVMs], and AVMs) and that the urinary increase in these proteins parallels the tissue remodeling seen in diffuse and expanding vascular malformations. [11] They suggested that drugs targeting bFGF or MMPs may be an adequate therapeutic strategy for patients suffering from these vascular anomalies.

Inherited forms of vascular malformations are rare [5] but may offer insight into the molecular mechanisms and signaling pathways involved in the pathogenesis of these lesions. This may in turn identify potential novel therapeutic targets, though at present, it is unclear whether the more common sporadic vascular malformations share similar biologic mechanisms with the infrequent inherited vascular malformations.

An AVM is a hemodynamically active fast-flow vascular malformation. Arterial feeders and enlarged draining veins directly connect through micro- and macroarteriovenous fistulas that create the nidus or epicenter of the AVM. AVMs may occur both superficially and viscerally. They are usually present at birth and rarely regress. [5] They have a normal endothelial cell cycle and grow commensurately with the child. [3, 1]

The natural history of AVMs is organized into a clinical staging system proposed by Schobinger at the 1990 ISSVA meeting in Amsterdam (see Table 3 below). [12]

Table 3. Schobinger Staging for AVMs (Open Table in a new window)

Stage Description
I - Quiescence Pink-bluish stain, warmth, and arteriovenous shunting are revealed by Doppler scanning. The arteriovenous malformation mimics a capillary malformation or involuting hemangioma.
II - Expansion The description is the same as stage I, plus enlargement, pulsations, thrill, and bruit and tortuous/tense veins.
III - Destruction The description is the same as stage II, plus dystrophic skin changes, ulceration, bleeding, persistent pain, or tissue necrosis. Bony lytic lesions may occur.
IV - Decompensation The description is the same as stage III, plus congestive cardiac failure with increased cardiac output and left ventricle hypertrophy.
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Epidemiology

Although vascular anomalies are among the most common pediatric abnormalities, occurring in approximately 1% of children, [13] AVMs are rare. [5]

Most AVMs are evident at birth (40% in a study of 200 AVMs by Enjolras et al), [14] though they may not be clinically relevant. Mulliken and Glowacki noted that 90% of vascular malformations were present at birth in a series of 23 patients; however, these lesions were predominately venous in type and may not be representative of AVMs per se. [3]

The female-to-male ratio for vascular malformations is 1:1. [3, 14]

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Prognosis

AVMs never regress and usually follow the stages outlined by Schobinger (see Pathophysiology). Morbidity and mortality are dependent on several factors, as follows:

  • Location and size of the AVM
  • Whether the AVM is surgically accessible or amenable to palliative embolization/sclerotherapy
  • Presence or absence of congestive heart failure

The prognosis is excellent when AVMs are managed by an interdisciplinary team, and the best success is achieved in surgically accessible lesions treated with combined embolization and complete surgical resection. (See the image below.)

Panel A: 12-year-old female with right facial arte Panel A: 12-year-old female with right facial arteriovenous malformation (AVM) s/p sclerotherapy. Panel B: 12.5-year-old female 4 months after resection of right facial AVM with preoperative embolization, complex closure, and lip reconstruction with rotational advancement flaps. Panel C: 13-year-old female with good recovery and no residual palpable or pulsatile AVM. Panel D: 14-year-old female with regrowth of AVM after the onset of puberty.
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