title: Aneurysm sac hygroma: a cause of endotension.
abstract: OBJECTIVE
  To describe a new pathophysiological mechanism for endotension.
  
  
  METHODS
  Four patients developed aneurysm sac expansion after repair of abdominal aortic aneurysms, one with a conventional polytetrafluoroethylene (PTFE) graft and the others with a variety of commercially made endografts (2 PTFE, 1 Dacron). Pressures within the sacs were nonpulsatile and approximately half the systemic blood pressure. Attenuation on computed tomography (CT) was significantly less in the sac than in the graft in 3 of the patients. A clear, highly viscous fluid was aspirated from all 4 sacs, supporting the diagnosis of aneurysm sac hygroma. Prominent local hyperfibrinolysis in the sac was combined with signs of local coagulation activation.
  
  
  CONCLUSIONS
  A new mechanism for continued sac expansion based on aneurysm sac hygroma is proposed. Measurement of attenuation may be of diagnostic value. It is further proposed that local hyperfibrinolysis/coagulation may promote rebleeding, liquefaction, and continued expansion analogous to the chronic subdural hematoma.
authors.affiliation: Department of Vascular Surgery, Sahlgrenska University Hospital, Göteborg, Sweden. bo.risberg@surgery.gu.se
authors.forename: B
authors.initials: B
authors.lastname: Risberg
authors.forename: M
authors.initials: M
authors.lastname: Delle
authors.forename: E
authors.initials: E
authors.lastname: Eriksson
authors.forename: H
authors.initials: H
authors.lastname: Klingenstierna
authors.forename: L
authors.initials: L
authors.lastname: Lönn
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects*; D005342:Fibrinolysis / Q000502:physiology; D006801:Humans; D018191:Lymphangioma, Cystic / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011312:Pressure; D011475:Prosthesis Failure; D013396:Suction; D014057:Tomography, X-Ray Computed