title: Transvenous extrahepatic portacaval shunt: feasibility study in a Swine model.
abstract: OBJECTIVE
  To evaluate the feasibility of intravascular ultrasonography (US)-guided access to the extrahepatic segment of the main portal vein (PV) to create a transvenous extrahepatic portacaval shunt (TEPS) as an easier and more durable alternative to transjugular intrahepatic portosystemic shunt.
  
  
  METHODS
  PV access from the inferior vena cava (IVC) to the main PV was performed in eight pigs by using intravascular US guidance. Either a prototype stent-graft (n = 6) or Wallgraft (n = 2) was used to create the shunt. Intravascular US demonstrated the main PV to be in direct contact with the IVC in all animals. A mean of 1.75 needle passes were needed to enter the PV. Immediate postprocedure computed tomography (CT) of the abdomen helped identify and quantify the presence of hemoperitoneum. Shunt venography was performed at 2 weeks, followed by necropsy.
  
  
  RESULTS
  PV access and TEPS creation were successful in all animals. Contrast medium extravasation, due to inadequate coverage of the portacaval tract, was identified in four procedures and addressed by the placement of additional devices in three cases and prolonged balloon inflation in one. Abdominal CT demonstrated small amounts of hemoperitoneum in five animals and moderate to large amounts in three. Two animals did not live to the 2-week follow-up study. One animal was sacrificed on the day of the procedure owing to intraperitoneal hemorrhage; the second died of intussusception-related bowel necrosis 10 days after TEPS creation. Shunts were occluded or severely stenotic at venography and necropsy in the remaining six animals.
  
  
  CONCLUSIONS
  TEPS is technically feasible after intravascular US-guided PV access.
authors.affiliation: John S. Dunn Center for Radiological Sciences, Section of Vascular and Interventional Radiology, Department of Diagnostic Radiology, University of Texas M.D. Anderson Cancer Center, Houston, 77030-4009, USA. mwallace@mdanderson.org
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Wallace
authors.forename: Kamran
authors.initials: K
authors.lastname: Ahrar
authors.forename: L Clifton
authors.initials: LC
authors.lastname: Stephens
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Wright
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005119:Extravasation of Diagnostic and Therapeutic Materials; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006465:Hemoperitoneum / Q000209:etiology; D008297:Male; D011167:Portacaval Shunt, Surgical / Q000379:methods*; D011183:Postoperative Complications; D013552:Swine; D014057:Tomography, X-Ray Computed; D018084:Ultrasonography, Interventional