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Abstract

Introduction: The Direct thrombin inhibitors (DTI) are the standard of care for the treatment of proven or suspected Heparin Induced Thrombocytopenia (HIT). The management of DTI therapy is complicated by a narrow therapeutic index, frequent monitoring and titration, and interclass pharmacokinetic variability. Our institution formulated and implemented a dosing and titration guideline for bivalirudin and argatroban. Methods: Fifty consecutive patients receiving a DTI for proven or suspected HIT were identified following the implementation of the guideline. This group was compared to a control group of 50 consecutive patients who were managed with DTI therapy prior to guideline implementation. The data were evaluated and compared between the two groups including baseline characteristics, metrics relevant to achieving goal aPTT, and adverse events. Results: Notable proportions of patients in both cohorts, pre and post guideline implementation, were in the cardiac surgery Intensive Care Unit (40% and 44%) and on bivalirudin (76% and 80%).The percentage of patients reaching therapeutic aPTT goals increased after implementation of the guideline (72% vs. 92%, p=0.016), as did patients reaching therapeutic aPTT goals on initial dose administered (16% vs. 44%, p<0.01). Number of dose changes required to reach therapeutic aPTT goal decreased after implementation (3.14 + 3.02 vs. 1.85 + 2.78, p <0.05).There was a trend toward reduced median hours to therapeutic aPTT: 17.13 (6.00-36.75) vs. 10 (3.50- 28.00), p = 0.06. No differences in bleeding, thrombosis or critical aPTT values were observed. Conclusions: The percentage of patients reaching therapeutic aPTT goals significantly improved after the implementation of a DTI dosing guideline with no significant changes in thromboembolic events.