title: Evaluation of coagulation in dogs with partial or complete extrahepatic biliary tract obstruction by means of thromboelastography.
abstract: OBJECTIVE
  To characterize in vitro coagulation status in a cohort of dogs with extrahepatic biliary tract obstruction (EHBO) and to evaluate these patients for hypercoagulability by means of thromboelastography.
  
  
  METHODS
  Prospective cohort study. Animals-10 dogs with EHBO and 19 healthy control dogs.
  
  
  METHODS
  Partial or complete EHBO was confirmed via exploratory celiotomy. Venous blood samples were collected for evaluation of prothrombin time (PT) and activated partial thromboplastin time (APTT); fibrinogen and D-dimer concentrations; protein C and antithrombin activities; and factor VII, VIII, and XI coagulant activities in plasma as well as thromboelastography in whole blood. Thromboelastography variables were measured from the thromboelastography tracing, and a coagulation index was calculated. Thromboelastography results were compared with those of healthy control dogs previously evaluated by the same laboratory.
  
  
  RESULTS
  Hypercoagulability was diagnosed in all dogs with EHBO on the basis of a high coagulation index. Thromboelastography variables, including maximal amplitude, α-angle, and coagulation index, were significantly higher, and K (clot formation time) and R (reaction time) were significantly lower in these dogs than in control dogs. All dogs with EHBO had PT and APTT within respective reference ranges. Plasma D-dimer and fibrinogen concentrations were above reference ranges in 8 and 7 dogs, respectively, and protein C and antithrombin activities were below reference ranges in 3 and 1 dogs, respectively.
  
  
  CONCLUSIONS
  In vitro hypercoagulability was commonly detected in dogs with naturally occurring EHBO. The traditional view of EHBO as a disease that causes hypocoagulability may need to be reconsidered.
authors: Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. philmayhew@gmail.com
authors: Philipp D
authors: PD
authors: Mayhew
authors: Michelle R
authors: MR
authors: Savigny
authors: Cynthia M
authors: CM
authors: Otto
authors: Dorothy Cimino
authors: DC
authors: Brown
authors: Marjory B
authors: MB
authors: Brooks
authors: Adrienne M
authors: AM
authors: Bentley
authors: Jeffrey J
authors: JJ
authors: Runge
authors: Mary Beth
authors: MB
authors: Callan
mesh_terms: D000818:Animals; D017734:Bile Ducts, Extrahepatic / Q000473:pathology*; D001778:Blood Coagulation Disorders / Q000175:diagnosis / Q000209:etiology / Q000662:veterinary*; D002779:Cholestasis / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D004283:Dog Diseases / Q000209:etiology / Q000473:pathology*; D004285:Dogs; D005260:Female; D008297:Male; D013916:Thrombelastography / Q000379:methods / Q000662:veterinary*