title: Clinical significance of cerebrovascular gas emboli during polidocanol endovenous ultra-low nitrogen microfoam ablation and correlation with magnetic resonance imaging in patients with right-to-left shunt.
abstract: BACKGROUND
  Foam generated by manual agitation of liquid sclerosant with air or gas is routinely utilized to treat refluxing veins. Although generally well tolerated, serious neurological events have been reported. The composition and properties of the foam, including bubble size and gaseous components, may contribute to the potential for microcirculatory obstruction and cerebral ischemia. We tested an ultra-low nitrogen polidocanol endovenous microfoam with controlled bubble size and density and hypothesized that patients at risk due to the presence of middle cerebral artery (MCA) bubble emboli during microfoam injection would not demonstrate evidence of clinical or subclinical cerebral infarction.
  
  
  METHODS
  Patients with great saphenous vein incompetence were treated with ultra-low nitrogen (≤ 0.8%) polidocanol endovenous microfoam injected under ultrasound guidance. Patients with right-to-left shunt were included to evaluate the safety of cerebral arterial bubbles. All patients with MCA emboli detected by transcranial Doppler during endovenous microfoam ablation received intensive surveillance for microinfarction, including brain magnetic resonance imaging and measurement of cardiac troponin-I.
  
  
  RESULTS
  MCA bubble emboli were detected in 60 of 82 treated patients; 22 patients had no detectable emboli. Among patients with MCA bubbles detected, 49 (82%) had ≤ 15 bubbles. No patients developed magnetic resonance imaging abnormalities, neurological signs, or elevated cardiac troponin.
  
  
  CONCLUSIONS
  Patients treated with foamed liquid sclerosants are commonly exposed to cerebrovascular gas bubbles. In this series of 60 high-risk patients with MCA bubble emboli during or after treatment with ultra-low nitrogen polidocanol endovenous microfoam, there was no evidence of cerebral or cardiac microinfarction. The results of this study cannot be generalized to foams compounded using bedside methodologies, since the composition of these foams is substantially different.
authors.affiliation: Wake Forest University School of Medicine, Winston-Salem, NC, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Regan
authors.forename: Kathleen D
authors.initials: KD
authors.lastname: Gibson
authors.forename: Janet E
authors.initials: JE
authors.lastname: Rush
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Shortell
authors.forename: Stanley A
authors.initials: SA
authors.lastname: Hirsch
authors.forename: David D I
authors.initials: DD
authors.lastname: Wright
mesh_terms: D000293:Adolescent; D000328:Adult; D002544:Cerebral Infarction / Q000175:diagnosis / Q000453:epidemiology*; D004618:Embolism, Air / Q000453:epidemiology*; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000453:epidemiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology; D000077423:Polidocanol; D011092:Polyethylene Glycols / Q000008:administration & dosage*; D012501:Saphenous Vein; D012597:Sclerosing Solutions / Q000008:administration & dosage*; D015911:Sclerotherapy / Q000009:adverse effects / Q000379:methods*; D018616:Ultrasonography, Doppler, Duplex; D017585:Ultrasonography, Doppler, Transcranial; D018084:Ultrasonography, Interventional; D014648:Varicose Veins / Q000000981:diagnostic imaging / Q000628:therapy*; D055815:Young Adult
chemical_list: D012597:Sclerosing Solutions; D000077423:Polidocanol; D011092:Polyethylene Glycols