title: Clinical experience of anti-Xa monitoring in critically ill dogs receiving dalteparin.
abstract: OBJECTIVE
  To describe a population of critically ill dogs receiving dalteparin monitored with an anti-Xa assay, to assess the potential utility of serial monitoring, and to investigate the association between pre-treatment thromboelastography (TEG) and the ability to achieve targeted anti-Xa activity.
  
  
  METHODS
  Descriptive retrospective study.
  
  
  METHODS
  Veterinary teaching hospital.
  
  
  METHODS
  Thirty-eight client-owned dogs receiving dalteparin and monitored with an anti-Xa assay.
  
  
  METHODS
  None.
  
  
  RESULTS
  Medical records were retrospectively reviewed for signalment, underlying disease, clinicopathological data, occurrence of thromboembolic events, complications, and outcome. Thirty-eight dogs receiving dalteparin were monitored with an anti-Xa assay. Diseases included hematological disease, protein-losing disease, neoplastic disease, and septic processes. Pretreatment hypercoagulability was present in 34/35 dogs by assessment of TEG. Five cases of thromboembolism were confirmed prior to starting treatment and 4 cases occurred during hospitalization. Bleeding complications were rare (3/38) and 29/38 dogs survived to discharge. Interpretation of the anti-Xa assay allowed for dose adjustment although reliable achievement of target anti-Xa activity was not demonstrated. Dogs with higher G values on pretreatment TEG were significantly less likely to achieve the target anti-Xa activity (ie, be above or below the target range).
  
  
  CONCLUSIONS
  Dalteparin was well tolerated in a heterogeneous population of dogs. However, dose adjustment in response to anti-Xa activity interpretation inconsistently resulted in subsequent attainment of the target anti-Xa range. Development of guidelines may be warranted to more consistently achieve the target range. Dogs that appear more hypercoagulable on pre-treatment TEG may require closer monitoring and greater dose adjustment to achieve the target anti-Xa range.
authors.affiliation: Section of Emergency and Critical Care, Department of Clinical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, MA, 01536.
authors.forename: Alex M
authors.initials: AM
authors.lastname: Lynch
authors.forename: Armelle M
authors.initials: AM
authors.lastname: deLaforcade
authors.forename: Claire R
authors.initials: CR
authors.lastname: Sharp
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000008:administration & dosage; D016638:Critical Illness; D017985:Dalteparin / Q000009:adverse effects / Q000627:therapeutic use*; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D015951:Factor Xa / Q000032:analysis / Q000187:drug effects; D065427:Factor Xa Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D013927:Thrombosis / Q000517:prevention & control / Q000662:veterinary
chemical_list: D000925:Anticoagulants; D065427:Factor Xa Inhibitors; D015951:Factor Xa; D017985:Dalteparin
keywords: anticoagulation; canine; low molecular weight heparin; thromboelastography