Evaluation of 2 weight-based protocols for administration of heparin

Abstract

Background: In 1996, a weight-based protocol for administration of heparin was implemented and assessed at the authors' institution. Since then, several modifications have been made, including introduction of a lower-target protocol. These changes warranted re-evaluation of the standard and lower-target protocols. Objective: To determine and compare the efficacy and safety of the standard and lower-target protocols for heparin administration and to descriptively compare these findings with the original 1996 protocol. Methods: This 5-month retrospective, observational study involved 100 consecutive patients, 50 assigned to each of the 2 current protocols (standard and lower target), who were treated between September 2006 and January 2007. The primary outcomes were efficacy, represented by the time to achieve partial thromboplastin time (PTT) above the lower limit of the therapeutic range and within the therapeutic range, and safety, as indicated by the incidence of major bleeding and thromboembolic events over the entire course of heparin therapy. Results: There were no significant differences between the standard and lower-target protocols with respect to median time to achieve PTT above the lower limit of the therapeutic range (6.0 h versus 6.3 h, respectively; p = 0.24) or median time to achieve PTT within the therapeutic range (14.4 h versus 14.3 h, respectively, p = 0.93). Compared with the original 1996 protocol, these protocols appeared to have shorter times to achieve both of these outcomes. The rate of adverse events was infrequent, with fewer episodes of major bleeding (1%, for both current protocols combined) than in the 1996 study (10%). Conclusions: The 2 current weight-based protocols for administration of heparin appeared to have similar efficacy and safety and appeared to perform at least as well as the original 1996 protocol.