title: Embolization of high flow arteriovenous malformations: experience with use of superabsorbent polymer microspheres.
abstract: OBJECTIVE
  To determine efficacy, safety, and requirements for adjunctive embolization or surgery in the treatment of symptomatic arteriovenous malformations (AVMs) with superabsorbent polymer microsphere (SAP-MS) particles.
  
  
  METHODS
  SAP-MS particles (sodium acrylate and vinyl alcohol copolymer) are nonbiodegradable spheres with a precisely calibrated diameter. SAP-MS particles swell by absorbing fluids and become soft and deformable. Twenty-five patients (16 men, nine women; mean age, 32 y; range 12-66 y) with symptomatic facial (n = 5), upper- (n = 8) and lower- (n = 12) extremity AVMs were treated primarily (n = 23) or preoperatively (n = 2) by transarterial embolization (TAE) treatment with use of SAP-MS particles. Direct puncture embolization (DPE; n = 4) and/or surgical intervention (n = 5; ie, skin graft, resection, or amputation) were required. Surgical specimens from the resected (n = 2) and the amputated (n = 2) patients were evaluated histologically. Follow-up study, including clinical findings and imaging studies, was performed at intervals ranging from 3 months to 1 year. Clinical outcome was evaluated retrospectively, depending on the subjective improvement of symptoms and signs, according to the medical records.
  
  
  RESULTS
  Seventy-two TAEs (range, 1-11; mean, 2.8) and 12 DPEs (range, 1-3; mean, 2.4) were performed during the mean follow-up period of 38 months (range, 7-110 mo). Twenty patients (80%) experienced symptom improvement by embolotherapy alone (n = 17) or in combination with surgery (n = 3). One lip and two finger AVMs were totally removed by surgical excision or amputation after TAE treatment. In diffuse upper- (n = 1) and lower- (n = 1) extremity AVMs, the symptoms were uncontrolled. No nerve injury or skin necrosis was observed after TAE treatment with SAP-MS particles. Mucosal necrosis was induced by DPE with ethanol in one patient. Histologically, SAP-MS particles penetrated intralesional vessels and conformed to the vessel lumen, resulting in tight vessel occlusion. Minimal perivascular reaction was observed.
  
  
  CONCLUSIONS
  SAP-MS particles were used safely in TAE treatment of AVM. TAE treatment with use of SAP-MS particles was suitable for certain symptomatic AVMs, but diffuse AVMs remain a challenge and a combination of alternative methods will be necessary for further strategy.
authors.affiliation: Department of Radiology, Osaka University Graduate School of Medicine, Suita, Japan. osuga@radiol.med.osaka-u.ac.jp
authors.forename: Keigo
authors.initials: K
authors.lastname: Osuga
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hori
authors.forename: Hikaru
authors.initials: H
authors.lastname: Kitayoshi
authors.forename: Azzam Anwar
authors.initials: AA
authors.lastname: Khankan
authors.forename: Atsuya
authors.initials: A
authors.lastname: Okada
authors.forename: Takashi
authors.initials: T
authors.lastname: Sugiura
authors.forename: Takamichi
authors.initials: T
authors.lastname: Murakami
authors.forename: Ko
authors.initials: K
authors.lastname: Hosokawa
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000180:Acrylic Resins / Q000627:therapeutic use*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001165:Arteriovenous Malformations / Q000628:therapy*; D002648:Child; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D011108:Polymers / Q000627:therapeutic use*; D011145:Polyvinyls / Q000627:therapeutic use*
chemical_list: D000180:Acrylic Resins; D011108:Polymers; D011145:Polyvinyls; C569390:acrylic acid-vinyl alcohol copolymer