Original Article

Do Different Heparin Brands Influence Activated Clotting Times?

¹ Clinical Perfusion, St. Boniface General Hospital, University of Manitoba, Winnipeg, Manitoba, Canada
² Department of Anesthesia, St. Boniface General Hospital, University of Manitoba, Winnipeg, Manitoba, Canada

^* Address correspondence to: Louise Dyck, Chief Perfusionist, St. Boniface General Hospital, 409 Tache Avenue, Winnipeg, Manitoba R2H 2A6 Canada

Abstract

A change in brand suppliers of heparin at our institution resulted in a number of anecdotal reports of possible differences in potency. Both products are marketed as heparin sodium extracted from porcine intestinal mucosa. Heparin Leo® is 1000 international units (British Pharmacopeia) per ml. while Hepalean® is 10000 United States Pharmacopeia (U.S.P) units per ml.

Perfusion records were retrospectively reviewed for one month periods when Heparin Leo® (n=52) or Hepalean® (n=61) were used to provide anticoagulation therapy for cardiopulmonary bypass.

Heparin Leo® was found to be less clinically potent than Hepalean®. While increasing the initial loading dose of Heparin Leo® by 5% (378 vs 395 units/kg⁻¹), the initial post load activated clotting time (ACT) was 17% lower (556 vs 666 seconds). Heparin units required per kilogram per minute of cardiopulmonary bypass were 23% higher for Heparin Leo®. Additionally 8 of 52 Heparin Leo® patients did not achieve an initial post load ACT of greater than 400 sees while this occurred in 2 of 61 patients treated with Hepalean®. These results were statistically significant.

British Pharmacopeia and United States Pharmacopeia heparin reference standards differences are insufficient to explain the discrepancies observed in this study.