title: High prevalence of right-to-left shunt in patients with symptomatic great saphenous incompetence and varicose veins.
abstract: BACKGROUND
  Varicose veins are common and increasingly are being treated by less invasive endoscopic methods such as foam sclerotherapy. Patent foramen ovale (PFO) is also common, present in approximately one-quarter of adults. PFO allows bubbles introduced by foam sclerotherapy to cross into the general circulation, potentially causing cerebral artery gas embolization with unevaluated consequences.
  
  
  METHODS
  Men and women aged 18 to 60 years with symptomatic varicose veins (CEAP C(3-5)) responded to an advertisement to recruit volunteers for a study on endovenous microfoam ablation (EMA). Participants' veins were screened by duplex ultrasound imaging, and those with isolated great saphenous vein (GSV) incompetence were tested for right-to-left (R-L) vascular shunt using transcranial Doppler (TCD) of the middle cerebral artery to detect the presence of bubble emboli after an injection of an agitated saline, blood, and air mixture as a contrast at rest and with the Valsalva maneuver.
  
  
  RESULTS
  Of 221 participants tested for R-L shunt, 85 (38.5%) were positive at rest (95% confidence interval [CI], 32.5-45.2) and 114 (51.8%) were positive after the Valsalva maneuver (95% CI, 45.4-58.5). A total 130 patients (58.8%) were positive for R-L shunt at rest or after Valsalva (95% CI, 52.5%-65.1%). This is significantly higher than the reported 26% prevalence of PFO in the general population (95% CI, 24.4-30.1).
  
  
  CONCLUSIONS
  The prevalence of R-L shunt in patients with GSV incompetence CEAP C(3-5) in this study was higher than expected in the general population. TCD does not differentiate between intracardiac shunts and intrapulmonary shunts, so this observation needs further investigation. This link between R-L shunt and varicose veins is novel and, whether etiologic or functional, may improve the understanding of both conditions. The findings have importance in the treatment of varicose veins with foam sclerotherapy and EMA.
authors.affiliation: BTG International Ltd in London, London, United Kingdom. David.wright@btgplc.com
authors.forename: David D
authors.initials: DD
authors.lastname: Wright
authors.forename: Kathleen D
authors.initials: KD
authors.lastname: Gibson
authors.forename: Jean
authors.initials: J
authors.lastname: Barclay
authors.forename: Alexander
authors.initials: A
authors.lastname: Razumovsky
authors.forename: Janet
authors.initials: J
authors.lastname: Rush
authors.forename: Charles N
authors.initials: CN
authors.lastname: McCollum
mesh_terms: D000328:Adult; D003326:Coronary Circulation; D004739:England / Q000453:epidemiology; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000209:etiology; D008297:Male; D008875:Middle Aged; D000077423:Polidocanol; D011092:Polyethylene Glycols / Q000009:adverse effects; D015995:Prevalence; D011652:Pulmonary Circulation; D012039:Regional Blood Flow; D012501:Saphenous Vein / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012597:Sclerosing Solutions / Q000009:adverse effects; D015911:Sclerotherapy / Q000009:adverse effects; D012720:Severity of Illness Index; D018616:Ultrasonography, Doppler, Duplex; D017585:Ultrasonography, Doppler, Transcranial; D014481:United States / Q000453:epidemiology; D014636:Valsalva Maneuver; D014648:Varicose Veins / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D014689:Venous Insufficiency / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology / Q000628:therapy; D055815:Young Adult
chemical_list: D012597:Sclerosing Solutions; D000077423:Polidocanol; D011092:Polyethylene Glycols