Comparison of 2 weight-based heparin dosing nomograms in neurology and vascular surgical patients

Unfractionated heparin sodium (UFH) is used in neurology and vascular surgical patients to treat and prevent thromboembolic occlusions and requires weight-based dosing to achieve a therapeutic range; however, the optimal dosing strategy is not known. This study sought to determine whether an intravenous (IV) weight-based UFH dosing nomogram based on an 80-unit/kg bolus and 18-unit · kg(-1) · h(-1) initial infusion rate achieves therapeutic anticoagulation [activated partial thromboplastin time (aPTT), 65-110 seconds] more rapidly than that based on a 60-unit/kg bolus and 12-unit · kg(-1) · h(-1) initial infusion rate in 98 neurology and vascular surgery patients.

The study consisted of a retrospective chart review of adults prescribed and administered IV UFH for >6 hours, admitted under the neurology or vascular surgery teams and administered UFH for transient ischemic attack, stroke, acute ischemic limb, or postoperative revascularization.

The time to therapeutic aPTT analysis showed superiority of the higher dose (P = 0.04, log-rank test). At 6 hours, there was a significantly greater proportion of patients within the therapeutic range in the higher dose group (36.0% versus 16.7%, P = 0.03), with fewer subtherapeutic aPTTs (34.0% versus 70.8%, P < 0.001) and more supratherapeutic aPTTs (30.0% versus 12.5%, P = 0.034).

A weight-based nomogram for IV UFH using an 80-unit/kg bolus and an initial infusion rate of 18 units · kg(-1) · h(-1) showed a more rapid achievement of therapeutic aPTT when compared with a 60:12 dosing nomogram. Future research assessing a 70-unit/kg bolus dose is recommended.