Evaluation of a multi‐target direct thrombin inhibitor dosing and titration guideline for patients with suspected heparin‐induced thrombocytopenia

To the Editor: Heparin-induced thrombocytopenia (HIT) is an antibody-mediated adverse drug reaction that can occur in patients receiving heparinoid therapy [1,2]. Management of HIT consists of discontinuation of the heparinoid and anticoagulation using a direct thrombin inhibitor (DTI), such as argatroban and bivalirudin. Institutions have implemented dosing guidelines for initial DTI dosing and titration. Standardization of DTI dosing and titration using a nursing driven guideline titrating to an activated partial thromboplastin time (aPTT) goal of 50–80 has been shown to reduce time and number of titrations to therapeutic aPTT [3]. An analysis of two dosing guidelines for argatroban achieved an aPTT goal of 50–70 [4]. To our knowledge, currently no published bivalirudin dosing guideline exists that allows for a more stringent aPTT goal. Brigham and Women’s Hospital instituted a dosing and titration guideline for argatroban and bivalirudin that allowed the prescriber to select between three therapeutic aPTT goals: 50–80, 50–70, or 60–80 (Table 1). The protocol provided guidance for agent selection and dosing strategy based on age, organ function, and clinical condition. We hypothesized that a standardized dosing and titration guideline for DTIs improve achievement of therapeutic goals in patients with proven or suspected HIT. We conducted a single center, prospective, observational evaluation of patients treated with a DTI according to a dosing and titration guideline compared to a historic control