title: Development of Collateral Pathways in Tumor Obstruction of Confluence of the Hepatic Veins: Neither Fortuitous nor Innocuous.
abstract: Except in Budd-Chiari syndrome, alternative drainage pathways have been described rarely. The aim was to describe the alternative collaterals pathways due to tumor hepatic vein (HV) confluence obstruction and its impact in the setting of liver resection.
  
  
  
  Between 2006 and 2014, preoperative CT scans of 41 patients resected for malignant tumor(s) compressing the HV confluence were assessed for the presence of accessory veins and collateral veins. A 2:1 matched control group was used for comparison of intraoperative outcomes.
  
  
  
  Intrahepatic collaterals were observed in 28 (68%) patients, mostly between segments 3/4b and 5/4b, and subcapsular collaterals were observed in 12 (29%) patients. Patients with isolated right HV obstruction and with an accessory right HV present had fewer collateral pathways develop than patients without (6 of 10 patients [60%] vs 18 of 19 [95%]; p = 0.036). Segment 1 hypertrophy was present in only 6 (15%) patients. Compared with the control group, there was a significant increase in blood loss (900 mL [range 100 to 3,500 mL] vs 500 mL [range 100 to 2,600 mL]; p < 0.001), transfusion requirements (71% vs 15%; p < 0.001), and vascular clamping (hepatic pedicle: 85% vs 72%; p < 0.001, inferior vena cava: 41% vs 11%; p < 0.001) in case of HV obstruction.
  
  
  
  Development of collateral pathways is not fortuitous and depends on the number of HVs involved and pre-existing accessory veins. The increased blood loss observed in patients with collaterals leads to consider specific vascular clamping.
authors.affiliation: Department of Hepatobiliopancreatic Surgery, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France. Electronic address: louisebarbier@hotmail.fr.
authors.forename: Louise
authors.initials: L
authors.lastname: Barbier
authors.affiliation: Department of Radiology, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Ronot
authors.affiliation: Department of Hepatobiliopancreatic Surgery, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Monsinjon
authors.affiliation: Department of Histopathology, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Paradis
authors.affiliation: Department of Hepatobiliopancreatic Surgery, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Soubrane
authors.affiliation: Department of Radiology, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Vilgrain
authors.affiliation: Department of Hepatobiliopancreatic Surgery, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Belghiti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D001653:Bile Ducts, Intrahepatic; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D016022:Case-Control Studies; D018281:Cholangiocarcinoma / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D003097:Collateral Circulation; D005260:Female; D006498:Hepatectomy; D006503:Hepatic Veins / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies