Comparison of Clinical Scoring Tools to Predict Heparin-Induced Thrombocytopenia in Cardiac Surgery

Kari A. Allan, Jessica R. Crow, Jessica E. Chasler, Janhavi Athale, John P. Lindsley, Kenneth M Shermock, Michael Streiff, Glenn J.R. Whitman, Kathryn E. Dane

Research output: Contribution to journalArticlepeer-review


The 4Ts and HIT-Expert Probability (HEP) scoring tools for heparin-induced thrombocytopenia (HIT) have not been validated in cardiac surgery patients, and the reported sensitivity and specificity of the Post-Cardiopulmonary Bypass (CPB) scoring tool vary widely in the 2 available analyses. It remains unclear which of the available scoring tools most accurately predicts HIT in this population. Forty-nine HIT-positive patients who underwent on-pump cardiac surgery within a 6-year period were loosely matched to 98 HIT-negative patients in a 1:2 case-control design. The 4Ts, HEP, and CPB scores were calculated for each patient. Sensitivity and specificity of each tool were calculated using standard cut-offs. The Youden method was utilized to determine optimal cut-offs within receiver operating characteristic (ROC) curves of each score, after which sensitivities and specificities were recalculated. Using standard cut-offs, the sensitivities for the CPB, HEP, and 4Ts scores were 100%, 93.9%, and 69.4%, respectively. Specificities were 51%, 49%, and 71.4%, respectively. The AUC of the scoring tool ROC curves were 0.961 for the CPB score, 0.773 for the HEP score, and 0.805 for the 4Ts score. Using the Youden method-derived optimal cut-off of ≥3 points on the CPB score, sensitivity remained 100% with improved specificity to 88.9%. The CPB score is the preferred HIT clinical scoring tool in adult cardiac surgery patients, whereas the 4Ts score performed less effectively. A cut-off of ≥ 3 points on the CPB score could increase specificity while preserving high sensitivity, which should be validated in a prospective evaluation.

Original languageEnglish (US)
JournalSeminars in thoracic and cardiovascular surgery
StateAccepted/In press - 2021


  • Anticoagulation
  • Cardio-pulmonary bypass
  • Heparin-induced thrombocytopenia
  • thrombosis

ASJC Scopus subject areas

  • Surgery
  • Pulmonary and Respiratory Medicine
  • Cardiology and Cardiovascular Medicine


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