title: Clinical presentation, temporal relationship, and outcome in thirty-three patients with type 2 heparin-induced thrombocytopenia after cardiotomy.
abstract: BACKGROUND
  Type 2 heparin-induced thrombocytopenia is an uncommon but often fatal complication of heparin, frequently difficult to diagnose after cardiac surgery. In this series, we record the clinical presentation, temporal relationship, and treatment outcome of patients diagnosed with heparin-induced thrombocytopenia postoperatively.
  
  
  METHODS
  Thirty-three consecutive patients (1.1%) with a diagnosis of heparin-induced thrombocytopenia established by a greater than 50% drop in platelet count with or without a thrombotic event and a positive platelet factor-4 assay were reviewed. We recorded the clinical presentation, the time to presentation, treatment, and outcome (thrombosis, mortality). Univariate analysis was performed on 13 preoperative, operative, and postoperative variables.
  
  
  RESULTS
  The cohort was at increased mortality risk as a result of age (69.4 years), reduced cardiac function (46.8%), nonbypass operations (57.6%), emergency surgery (21.2%), and implantation of three assist devices. The mean time to suspect heparin-induced thrombocytopenia postoperatively was 5.4 days, with 22 cases (66.6%) occurring within 5 days. All patients had previous (within 3 months) exposure to heparin, and 66.6% had ongoing treatment with heparin before surgery. Overall mortality was 33%; thrombotic complications occurred in 15 patients (45.5%), with a mortality of 7 (46.6%) despite immediate cessation of heparin and treatment with a nonheparin analog. Thrombocytopenia without thrombosis occurred in 18 patients (54.5%), but a subgroup of 5 patients with nonthrombotic complications accounted for the 4 (22.2%) deaths.
  
  
  CONCLUSIONS
  Heparin-induced thrombocytopenia after cardiac surgery is uncommon but may occur within 5 days of surgery, further complicating diagnosis and treatment. Thrombotic complications result in a high mortality despite treatment with a nonheparin analog, and a subgroup of patients with thrombocytopenia fared poorly.
authors.affiliation: Division of Cardiac Surgery, McGill University Health Centre, Montreal, Quebec, Canada.
authors.forename: Calvin
authors.initials: C
authors.lastname: Wan
authors.forename: Margaret
authors.initials: M
authors.lastname: Warner
authors.forename: Benoit
authors.initials: B
authors.lastname: De Varennes
authors.forename: Patrick
authors.initials: P
authors.lastname: Ergina
authors.forename: Renzo
authors.initials: R
authors.lastname: Cecere
authors.forename: Kevin
authors.initials: K
authors.lastname: Lachapelle
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D006348:Cardiac Surgical Procedures; D002809:Chondroitin Sulfates / Q000008:administration & dosage / Q000627:therapeutic use; D015331:Cohort Studies; D003871:Dermatan Sulfate / Q000008:administration & dosage / Q000627:therapeutic use; D048909:Diabetes Complications / Q000453:epidemiology; D005260:Female; D005734:Gangrene / Q000209:etiology; D006493:Heparin / Q000009:adverse effects* / Q000276:immunology; D006497:Heparan Sulfate / Q000008:administration & dosage / Q000627:therapeutic use; D017052:Hospital Mortality; D006801:Humans; D007511:Ischemia / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010978:Platelet Factor 4 / Q000276:immunology; D011183:Postoperative Complications / Q000139:chemically induced* / Q000175:diagnosis / Q000276:immunology / Q000401:mortality / Q000628:therapy; D011184:Postoperative Period; D012189:Retrospective Studies; D012307:Risk Factors; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000145:classification / Q000175:diagnosis / Q000276:immunology / Q000628:therapy; D013927:Thrombosis / Q000188:drug therapy / Q000209:etiology / Q000401:mortality / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D001323:Autoantibodies; D002809:Chondroitin Sulfates; D003871:Dermatan Sulfate; D006493:Heparin; D006497:Heparan Sulfate; D010978:Platelet Factor 4; C035838:danaparoid