title: Chronic venous insufficiency in patients with absence of the inferior vena cava.
abstract: OBJECTIVE
  Up until now, knowledge of absence of the inferior vena cava (AIVC) is limited to case reports and small case series, usually reported shortly after diagnosis. To characterize long-term evolution of outcomes of patients with AIVC, we performed a survey of current practice in Belgium, The Netherlands, and Luxembourg (Benelux).
  
  
  METHODS
  Vascular surgeons and phlebologists in the Benelux area were asked to complete a questionnaire on medical history and treatment of each patient in follow-up at their practice with a diagnosis of AIVC.
  
  
  RESULTS
  The Benelux survey yielded 35 patients with AIVC, with a follow-up ranging from 0 to 28 years. Their median age was 40 years (range, 14-65 years), and 26 (74%) were male. Diagnosis of AIVC was made in 26 patients at the time of presentation with deep vein thrombosis (DVT). DVT was bilateral in 15 patients and involved one or both iliac veins in 21 (81% of all AIVC patients with acute DVT). Computed tomography scanning was used to detect AIVC in 29 patients. Thrombophilia was present in 16 (46%). The CEAP C classification was C4-6 in 17 right legs (49%) and 15 left legs (43%). Unilateral or bilateral ulceration had occurred in 11 patients in the past, and three had active ulceration. Long-term conservative treatment consisted of oral anticoagulant treatment in 28 patients and compression stockings in 27.
  
  
  CONCLUSIONS
  The results of this survey on AIVC illustrate the unfavorable long-term clinical evolution of these patients. They frequently present with advanced stages of chronic venous insufficiency at a relatively young age, with the development of unilateral or bilateral extensive DVT and subsequent moderate to severe post-thrombotic syndrome.
authors.affiliation: Department of Dermatology, Erasmus Medical Center, Rotterdam, The Netherlands; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium. Electronic address: m.demaeseneer@erasmusmc.nl.
authors.forename: Marianne G R
authors.initials: MG
authors.lastname: De Maeseneer
authors.affiliation: Department of Thoracic and Vascular Surgery, University Hospital Antwerp, Antwerp, Belgium.
authors.forename: Marjan
authors.initials: M
authors.lastname: Hertoghs
authors.affiliation: Department of Thoracic and Vascular Surgery, University Hospital Antwerp, Antwerp, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Lauwers
authors.affiliation: Department of Dermatology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Wendy
authors.initials: W
authors.lastname: Koeyers
authors.affiliation: Department of Vascular Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: de Wolf
authors.affiliation: Department of Vascular Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands; Department of Vascular Surgery, University Hospital RWTH Aachen, North Rhine-Westphalia, Germany.
authors.forename: Cees
authors.initials: C
authors.lastname: Wittens