Argatroban dosage requirements and outcomes in intensive care versus non-intensive care patients

To compare the outcomes of reduced-dose argatroban therapy in patients in the intensive care unit (ICU) with those of non-ICU patients.

Retrospective medical record review.

Large, academic, tertiary care hospital.

Thirty-eight ICU patients and 43 non-ICU patients who received the institutional protocol of argatroban 0.8 microg/kg/minute and 1.2 microg/kg/minute, respectively, between March 2004 and September 2005.

Data on patient demographics, argatroban dosing, heparin-induced thrombocytopenia antibody results, activated partial thromboplastin times (aPTTs), new thrombotic events, and major bleeding events were extracted from medical records. Time-weighted mean +/- SD doses of argatroban were 0.82 +/- 0.3 microg/kg/minute for ICU patients and 1.25 +/- 0.29 microg/kg/minute for non-ICU patients. Mean aPTT ratios were similar between groups: 2.07 +/- 0.53 for ICU patients and 2.00 +/- 0.45 for non-ICU patients. More than 70% of all aPTT ratios were therapeutic. More than 95% of patients in both groups achieved a therapeutic aPTT ratio during therapy. Fewer ICU patients than non-ICU patients had all therapeutic aPTT ratios during argatroban therapy (29% vs 51%, p=0.07). Thrombotic events occurred in six (16%) ICU patients versus none of the non-ICU patients (p=0.009). Thrombotic events occurred in 4 (31%) of the 13 ICU patients with confirmed heparin-induced thrombocytopenia. Major bleeding occurred in four (11%) ICU patients versus none of the non-ICU patients (p=0.04).

Both ICU and non-ICU patients require less than the manufacturer-recommended initial dosage of argatroban. However, ICU patients appear to be at an increased risk for bleeding and thrombotic events despite their attainment of therapeutic aPTTs.