title: Sonoclot® evaluation of single- and multiple-dose subcutaneous unfractionated heparin therapy in healthy adult dogs.
abstract: BACKGROUND
  Heparin therapy is difficult to monitor due to variation in animal response. While laboratory measurements of activated partial thromboplasin time (aPTT) and Anti-Xa activity (AXA) accurately describe heparin effect, their availability is limited.
  
  
  OBJECTIVE
  Sonoclot analysis would be as sensitive as AXA and aPTT to monitor effects of unfractionated heparin (UFH) in healthy adult dogs.
  
  
  METHODS
  Six adult mixed-breed dogs.
  
  
  METHODS
  A prospective study design was employed. On day 1, baseline samples were collected (CBC, PT, aPTT, and Sonoclot), and UFH (300 U/kg SC) was administered to 6 dogs following an IV loading dose of 50 U/kg. Sonoclot and aPTT were performed hourly for 12 hours. AXA was assayed at hours 3, 6, 9, and 12. UFH (300 U/kg q8 h SC) was administered at 12 hours, and subsequently (q8 h) for 2 additional days. On day 4, a final dose of UFH was administered, and a sampling protocol identical to day 1 was performed.
  
  
  RESULTS
  Sonoclot activated clotting time (ACT) and clot rate (CR) correlated with AXA (R = 0.69, R = 0.65, respectively, P < .001), although to a lesser degree than aPTT (R = 0.75, P < .001). Linear regression using ACT and CR as covariates indicated a stronger correlation with AXA (R = 0.73, P < .001). ACT values strongly correlated with aPTT (R = 0.87, P < .001).
  
  
  CONCLUSIONS
  Administration of UFH to healthy dogs results in progressive changes in Sonoclot values. AXA was correlated with a combination of ACT and CR and with aPTT. Sonoclot may play a role in monitoring UFH therapy; however, prospective studies evaluating its utility in clinical cases are warranted.
authors.affiliation: Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Babski
authors.forename: B M
authors.initials: BM
authors.lastname: Brainard
authors.forename: A G
authors.initials: AG
authors.lastname: Ralph
authors.forename: J R
authors.initials: JR
authors.lastname: Pittman
authors.forename: A
authors.initials: A
authors.lastname: Koenig
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000097:blood / Q000494:pharmacology*; D001780:Blood Coagulation Tests / Q000379:methods / Q000662:veterinary*; D004285:Dogs / Q000097:blood*; D005260:Female; D006493:Heparin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D000925:Anticoagulants; D006493:Heparin