Extracranial Arteriovenous Malformation Research Articles

Somatic MAP2K1 Mutations Are Associated with Extracranial Arteriovenous Malformation

Arteriovenous malformation (AVM) is a fast-flow, congenital vascular anomaly that may arise anywhere in the body. AVMs typically progress, causing destruction of surrounding tissue and, sometimes, cardiac overload. AVMs are difficult to control; they often re-expand after embolization or resection, and pharmacologic therapy is unavailable. We studied extracranial AVMs in order to identify their biological basis. We performed whole-exome sequencing (WES) and whole-genome sequencing (WGS) on AVM tissue from affected individuals. Endothelial cells were separated from non-endothelial cells by immune-affinity purification. We used droplet digital PCR (ddPCR) to confirm mutations found by WES and WGS, to determine whether mutant alleles were enriched in endothelial or non-endothelial cells, and to screen additional AVM specimens. In seven of ten specimens, WES and WGS detected and ddPCR confirmed somatic mutations in mitogen activated protein kinase kinase 1 (MAP2K1), the gene that encodes MAP-extracellular signal-regulated kinase 1 (MEK1). Mutant alleles were enriched in endothelial cells and were not present in blood or saliva. 9 of 15 additional AVM specimens contained mutant MAP2K1 alleles. Mutations were missense or small in-frame deletions that affect amino acid residues within or adjacent to the protein's negative regulatory domain. Several of these mutations have been found in cancers and shown to increase MEK1 activity. In summary, somatic mutations in MAP2K1 are a common cause of extracranial AVM. The likely mechanism is endothelial cell dysfunction due to increased MEK1 activity. MEK1 inhibitors, which are approved to treat several forms of cancer, are potential therapeutic agents for individuals with extracranial AVM.

Elevated Expression of Matrix Metalloproteinase-9 not Matrix Metalloproteinase-2 Contributes to Progression of Extracranial Arteriovenous Malformation.

Extracranial arteriovenous malformations (AVMs) are rare but dangerous congenital lesions arising from direct arterial-venous shunts without intervening capillaries. Progressive infiltration, expansion, and soft tissue destruction lead to bleeding, pain, debilitation and disfigurement. The pathophysiology of AVMs is not well understood. Matrix Metalloproteinases (MMPs) are thought to play an important role in pathologic processes underlying many diseases. This study investigates the expression of MMP-9 and MMP-2 in aggressive extracranial AVMs. The differential expression of MMP-9 and its regulatory factors is also examined. Herein we demonstrate that mRNA and protein expressions of MMP-9, but not MMP-2, are significantly higher in AVM tissues compared to normal tissues. The serum level of MMP-9, but not MMP-2, is also elevated in AVM patients compared to healthy controls. MMP-9/neutrophil gelatinase-associated lipocalin (NGAL) complex is also significantly increased in AVM tissues. The MMP-9/ tissue inhibitor of metalloproteases-1 (TIMP-1) complex presents as a major form detected in normal tissues. The increased and aberrant expression of MMP-9 and specific MMP-9 forms may help explain the constitutive vascular remodeling and infiltrative nature of these lesions. Specific MMP-9 inhibitors would be a promising treatment for AVMs.

Combined Trans-Arterial Coil and Percutaneous Onyx Embolization for Treatment of an Extracranial High-Flow Arteriovenous Malformation

Combined Trans-Arterial Coil and Percutaneous Onyx Embolization for Treatment of an Extracranial High-Flow Arteriovenous Malformation

English

Crisoid aneurysms of scalp are rare extracranial arteriovenous malformation which presents as varicoid scalp swelling which gradually increases in size over time, and has high propensity for massive hemorrhage. Multidetector computed tomography is very useful in its evaluation and treatment planning, particularly when the feeding vessels and draining channels have both intra and extracranial course. We are reporting a case of 22-year-old female patient presented with varicoid pulsatile swelling in parieto-occipital region of the scalp with gradual progression in size. INTRODUCTION: Crisoid aneurysm is an extracranial arteriovenous malformation of scalp. It is congenital in about 80% of cases and traumatic in about 20% of cases. The congenital variety occurs as a result of faulty differentiation of the primitive vessel complex with persistence of primitive arteriovenous interconnections which are normally replaced by an intervening capillary bed (2, 7). The feeding arteries and veins of the lesion are the naive vessels which are massively dilated, because of hemodynamic alteration. These lesions can present as varicoid pulsatile swelling over the scalp which are progressively increasing in size and has propensity to massive hemorrhage. The lesion mostly supplied by external carotid artery branches, and drains into extracranial veins as well as dural sinuses through emissary veins. They are normally supplied by superficial temporal and occipital artery. The superficial temporal artery is frequently involved in traumatic crisoid aneurysm due to its long unprotected course. Angiography is gold standard investigation to delineate the lesion and to exclude an intracranial component. However this facility is not available at our institution. Multidetector computed tomography can be used in non-invasive diagnosis and treatment planning of this complex arteriovenous malformation.

Is a Swine Model of Arteriovenous Malformation Suitable for Human Extracranial Arteriovenous Malformation? A Preliminary Study

A chronic arteriovenous malformation (AVM) model using the swine retia mirabilia (RMB) was developed and compared with the human extracranial AVM (EAVM) both in hemodynamics and pathology, to see if this brain AVM model can be used as an EAVM model. We created an arteriovenous fistula between the common carotid artery and the external jugular vein in eight animals by using end-to-end anastomosis. All animals were sacrificed 1 month after surgery, and the bilateral retia were obtained at autopsy and performed hematoxylin and eosin staining and immunohistochemistry. Pre- and postsurgical hemodynamic evaluations also were conducted. Then, the blood flow and histological changes of the animal model were compared with human EAVM. The angiography after operation showed that the blood flow, like human EAVM, flowed from the feeding artery, via the nidus, drained to the draining vein. Microscopic examination showed dilated lumina and disrupted internal elastic lamina in both RMB of model and nidus of human EAVM, but the thickness of vessel wall had significant difference. Immunohistochemical reactivity for smooth muscle actin, angiopoietin 1, and angiopoietin 2 were similar in chronic model nidus microvessels and human EAVM, whereas vascular endothelial growth factor was significant difference between human EAVM and RMB of model. The AVM model described here is similar to human EAVM in hemodynamics and immunohistochemical features, but there are still some differences in anatomy and pathogenetic mechanism. Further study is needed to evaluate the applicability and efficacy of this model.

Usefulness of computed tomographic angiography in the management of extracranial scalp arteriovenous malformation

Usefulness of computed tomographic angiography in the management of extracranial scalp arteriovenous malformation

Anaesthetic management of a child with massive extracranial arteriovenous malformation

Vascular tumors affect the head and neck commonly but arteriovenous malformations are rare. Vascular malformations are often present at birth and grow with the patient, usually only becoming significant later in childhood. Embolization has been the mainstay of treatment in massive and complex arteriovenous malformations. We present a case of massive extracranial arteriovenous malformation in a 7-year-old boy causing significant workload on right heart and respiratory distress. The management of angioembolization under general anaesthesia and anaesthetic concerns are presented.

Arteriovenous malformation in the pretragal region: Case report

Arteriovenous malformation (AVM) in the extracranial region is uncommon. The most common sites are cheek, ear, nose, and forehead in order of frequency in the extracranial region. Although the external ear is the second most common site for the extracranial AVM, AVM in the pretragal region has not been reported until now. We reported a case of AVM in the pretragal region, which was successfully removed by complete excision after preoperative selective embolization in a 32-year-old man. Combined superselective and particle embolization is a useful method to decrease the blood flow in the pretragal AVM. We successfully treated the patient for the AVM in the pretragal area by complete excision within 72 hours after the preoperative combined superselective and particle embolization. Although our case is similar to auricular AVMs in point of symptoms and treatment, this is the first case reported at this unusual site.

Arteriovenous malformation of the scalp with cerebral steal

Arteriovenous malformation of the scalp resulting from blunt trauma to the head is an unusual occurrence and is rarely associated with neurological sequelae. This case details an arteriovenous malformation with a cerebral steal phenomenon. A 21-year-old man presented with an enlarging, pulsatile mass in the right facial/temporal area without known cause. CT and angiography were consistent with a large arteriovenous malformation involving the external carotid system, causing a secondary cerebral steal that resulted in neurological symptoms including seizure. Surgical resection of the mass was undertaken. The patient had an uncomplicated preoperative course with complete resolution of all neurologic symptoms. Cerebral steal is an uncommon consequence of traumatic extracranial arteriovenous malformation. The current literature is reviewed, and the diagnostic approach as well as therapeutic options are discussed.

Anesthetic management in an angiographic suite: a retrospective review of 88 cases.

Advances in the field of interventional and diagnostic radiology have resulted in anesthesiologists becoming involved in angiographic suites. In the present study, we evaluated the characteristics of patients and the anesthetic management in an angiographic suite, to determine what factors influenced the patient outcome. Data pertaining to patients that were anesthetized at an angiographic suite in a university hospital between 1 January 2007 and 31 December 2007 were evaluated retrospectively. Specifically, we evaluated the patient characteristics and the types of anesthesia administered, to determine which factors were related to patient outcome. Sixty-four percent of the patients enrolled in this study were women. Cases involving coiling for unruptured and ruptured aneurysm, embolization for intracranial arteriovenous malformation and fistula, pediatric diagnostic angiography, embolization for extracranial arteriovenous malformation, and implantable cardioverter-defibrillator (ICD) implantation all required the involvement of anesthesiologists. Major postoperatve complications included pneumonia, atelectasis, and hydrocephalus. In addition, GCS, net fluid balance, and anesthesia time had influence on patient outcome. We evaluated the characteristics of patient groups, procedures, and postoperative complications in an angiographic suite. The results of our analysis revealed that a through understanding of nervous and vascular pathology, as well as knowledge of current interventional radiology, neuroanesthesia and vascular anesthesia techniques is essential for development of safe and effective care.

An Uncommon Presentation of an Extra-Cranial High Flow Arterio-Venous Malformation (AVM) Involving the Left Auricle

A 34-year-old male presented with a pulsatile lesion of the left external ear. Previous attempts at excision had resulted in uncontrollable bleeding. This time, under general anesthesia and a hypotensive technique, the lesion was approached distally and anteriorly through the conchal cartilage, the feeder vessels were ligated and the lesion was removed successfully with no resultant deformity to the external ear

Auricular Arteriovenous Malformation: Evaluation, Management, and Outcome

The external ear is the second most common site for extracranial arteriovenous malformation in the head and neck. This retrospective review of 41 patients with auricular arteriovenous malformation was based on medical records, imaging studies, and photographs. Data were collected on natural history, progression, and outcome; patients were questioned about quality of life after treatment. The median age at initial presentation was 26 years (range, 1 to 55 years), and Schobinger stage was I in two patients, II in 19 patients, and III in 20 patients. No patients had a Schobinger stage of IV. Expansion occurred during childhood in seven patients, adolescence in 14 patients, pregnancy in 10 patients, and adulthood in 10 patients. Distribution of auricular and extra-auricular arteriovenous malformation was not limited to "watershed" areas between vascular territories (angiosomes). Twelve patients were untreated (follow-up, 0.5 to 6 years). Mean follow-up time for the 29 treated patients was 5.19 years (range, 1 to 18.75 years). Proximal ligation in nine patients caused progression: eight of them underwent amputation and one had embolization. Fifteen patients had embolization only: the arteriovenous malformation worsened and amputation was necessary in six patients; in the remaining nine patients, two improved, four persisted, and three worsened. Of 20 patients who had auricular amputation, 16 (80 percent) were controlled, three (15 percent) improved, and one had unresectable, residual cervicofacial arteriovenous malformation. Of 22 of 29 treated patients surveyed, 81 percent were satisfied with their management. Hearing was either unaffected (n = 15) or diminished (n = 5); two patients noted decreased sound localization. The authors recommend periodic evaluation for stage I to II auricular arteriovenous malformation and intervention if there is evolution to stage III. Preoperative embolization and partial or total amputation effectively control auricular and para-auricular arteriovenous malformation. Embolization can be palliative in children or in patients who are not psychologically prepared for amputation. Extensive extra-auricular arteriovenous malformation requires individualized endovascular therapy and resection.

Arteriovenous Malformations of the Head and Neck: Natural History and Management

This is a retrospective review of 81 patients with extracranial arteriovenous malformation of the head and neck who presented to the Vascular Anomalies Program in Boston over the last 20 years. This study focused on the natural history and effectiveness of treatment. The male to female ratio was 1:1.5. Arteriovenous malformations occur in anatomic patterns. Sixty-nine percent occurred in the midface, 14 percent in the upper third of the face, and 17 percent in the lower third. The most common sites were cheek (31 percent), ear (16 percent), nose (11 percent), and forehead (10 percent). A vascular anomaly was apparent at birth in 59 percent of patients (82 percent in men, 44 percent in women). Ten percent of patients noted onset in childhood, 10 percent in adolescence, and 21 percent in adulthood. Eight patients first noted the malformation at puberty, and six others experienced exacerbation during puberty. Fifteen women noted appearance or expansion of the malformation during pregnancy. Bony involvement occurred in 22 patients, most commonly in the maxilla and mandible. In seven patients, the bone was the primary site; in 15 other patients, the bone was involved secondarily. Arteriovenous malformations were categorized according to Schobinger clinical staging: 27 percent in stage I (quiescence), 38 percent in stage II (expansion), and 38 percent in stage III (destruction). There was a single patient with stage IV malformation (decompensation). Stage I lesions remained stable for long periods. Expansion (stage II) was usually followed by pain, bleeding, and ulceration (stage III). Once present, these symptoms and signs inevitably progressed until the malformation was resected. Resection margins were best determined intraoperatively by the bleeding pattern of the incised tissue and by Doppler. Subtotal excision or proximal ligation frequently resulted in rapid progression of the arteriovenous malformation. The overall cure rate was 60 percent, defined as radiographic absence of arteriovenous malformation. Cure rate for small malformations was 69 percent with excision only and 62 percent for extensive malformations with combined embolization-resection. The cure rate was 75 percent for stage I, 67 percent for stage II, and 48 percent for stage III malformations. Outcome was not affected significantly by age at treatment, sex, Schobinger stage, or treatment method. Mean follow-up was 4.6 years. (Plast. Reconstr. Surg. 102: 643, 1998.)

Arteriovenous malformations of the head and neck: natural history and management.

This is a retrospective review of 81 patients with extracranial arteriovenous malformation of the head and neck who presented to the Vascular Anomalies Program in Boston over the last 20 years. This study focused on the natural history and effectiveness of treatment. The male to female ratio was 1:1.5. Arteriovenous malformations occur in anatomic patterns. Sixty-nine percent occurred in the midface, 14 percent in the upper third of the face, and 17 percent in the lower third. The most common sites were cheek (31 percent), ear (16 percent), nose (11 percent), and forehead (10 percent). A vascular anomaly was apparent at birth in 59 percent of patients (82 percent in men, 44 percent in women). Ten percent of patients noted onset in childhood, 10 percent in adolescence, and 21 percent in adulthood. Eight patients first noted the malformation at puberty, and six others experienced exacerbation during puberty. Fifteen women noted appearance or expansion of the malformation during pregnancy. Bony involvement occurred in 22 patients, most commonly in the maxilla and mandible. In seven patients, the bone was the primary site; in 15 other patients, the bone was involved secondarily. Arteriovenous malformations were categorized according to Schobinger clinical staging: 27 percent in stage I (quiescence), 38 percent in stage II (expansion), and 38 percent in stage III (destruction). There was a single patient with stage IV malformation (decompensation). Stage I lesions remained stable for long periods. Expansion (stage II) was usually followed by pain, bleeding, and ulceration (stage III). Once present, these symptoms and signs inevitably progressed until the malformation was resected. Resection margins were best determined intraoperatively by the bleeding pattern of the incised tissue and by Doppler. Subtotal excision or proximal ligation frequently resulted in rapid progression of the arteriovenous malformation. The overall cure rate was 60 percent, defined as radiographic absence of arteriovenous malformation. Cure rate for small malformations was 69 percent with excision only and 62 percent for extensive malformations with combined embolization-resection. The cure rate was 75 percent for stage I, 67 percent for stage II, and 48 percent for stage III malformations. Outcome was not affected significantly by age at treatment, sex, Schobinger stage, or treatment method. Mean follow-up was 4.6 years.

Progression of a Dural Arteriovenous Malformation Resulting in an Intracerebral Hematoma. A Case Report

A progressing, essentially extracranial arteriovenous malformation with purely external carotid feeders can involve the intracranial vasculature by enlargement of its drainage area. Thus it can cause cerebral dysfunction by an intracranial bleed or raised intracranial pressure due to venous engorgement. A case is described to support this possibility.