Excess Unfractionated Heparin Dosing for STEMI and NSTEMI

Discussion

The original heparin standing orders used by this site were based on recommendations for the treatment of venous thromboembolic disease. The ACCP consensus document also states that the dosing for patients with coronary thrombosis is lower than that for venous thrombosis.

The use of the one heparin dosing algorithm for all patients receiving heparin resulted in systematic dosing of cardiac patients at venous thromboembolic doses. However, the algorithm used by this site actually resulted in less excess dosing by the ACTION metric because they calculated based on ideal body weight. This lowered the calculated dose for patients who were of large body size. The ACTION metric was based on actual body weight. Yet, the risk related to bleeding from excess dosing of heparin is greatest in those of small body size, where ideal and actual weights are similar. Therefore, although this reduced the proportion reported to be excessively dosed, the dosing of smaller sized patients was still at higher than recommended for coronary thrombosis.

The heparin standing orders for this site resulted in 100% excess dosing on the ACTION metric for STEMI patients due to the substantially lower limits set for excess dosing (60 U/kg bolus maximum 4000 U, and 12 U/kg/h infusion maximum 1000 U/h). Actual body weight is the preferred weight measure for dosing, as it is simple, and patients over 80 kg will receive the dosing upper limits.

The ACTION report highlighted a systematic error, and triggered the site to review their heparin process. In addition, the experience of this site points out that algorithms based on PTT values need to be checked based on their corresponding relationship to the reference range, and therapeutic range as determined by control values.

ACC-NCDR ACTION Quality Improvement Registry

Weight-Based Unfractionated Heparin Dose for NSTEMI and STEMI The ACTION Heparin Algorithm is a template based on current ACC/AHA Unstable Angina/NSTEMI and STEMI Focused Update recommended initial heparin bolus and infusion dose, as well as a reasonable algorithm for subsequent weight-based dose adjustments (Slide 3).