aPTT Versus Anti Xa Monitoring of Unfractionated Heparin - a Retrospective Review of Clinical Outcomes

Data abstraction was completed through electronic medical record review of two hundred patients. Time point 0 was the date of changing to the new protocol. One hundred patients in reverse chronological order were reviewed for the original protocol and one hundred patients in chronological order with the new protocol. Data included demographics, duration of time prior to achieving therapeutic parameters, number of dosage changes, diagnosis of cancer, bleeding events and recurrent thrombotic events. Unpaired Student t tests were utilized to statistically analyze the differences between the cohorts.

Both methodologies achieved therapeutic levels rapidly. The Rosbourough method required statistically significant less dosage changes when compared to the Rashke method. The incidence of major and minor bleeding was similar between the two dosing algorithms. Although not statistically significant, the incidence of recurrent thromboses was numerically higher with the Rosbourough method compared to Rashke method. This is concerning and suggests that the higher loading dose may be more appropriate. A prospective comparison of these two monitoring methods using Rashke dosing is planned.

Off Label Use: Discuss alternative dosing and anti Xa monitoring of unfractionated heparin infusion.