Heparin management test versus activated coagulation time during cardiovascular surgery: Correlation with anti-Xa activity

Objective: To compare the abilities of the heparin management test (HMT) an d the activated coagulation time (ACT) to provide a measurement of heparin effect in patients undergoing cardiac or peripheral vascular surgery. These measurements of heparin effect were also compared with measurements of hep arin concentrations tested by anti-Xa activity. A secondary objective was t o compare the performance of the noncitrated HMT with that of the citrated HMT Design: A prospective study. Setting: A single-center study conducted in a university hospital. Participants: After human investigation committee approval and informed con sent were obtained, adult patients undergoing cardiac or peripheral vascula r surgery were included in this study. Interventions: In both surgical grou ps, blood was sampled for ACT, HMT, and anti-Xa activity. Each HMT was perf ormed on both noncitrated and citrated samples, Measurements and Main Results: As an indicator of heparin effect, the HMI h ad a strong correlation with the ACT (r = 0.899; P < 0.01). In addition, th e HMT had a significantly stronger correlation with anti-Xa activity than t he ACT (p < 0.01). The correlation obtained from the noncitrated samples wa s identical with that obtained from the citrated samples (r = 0.819; p < 0. 001 for both groups). Conclusion:The ability of the HMT and the ACI to measure heparin effect was similar. The HMT performed better than the ACI when using anti-Xa activity as a measure of heparin concentration. Noncitrated HMT results were simila r to citrated HMT results, thus supporting the use of fresh whole blood for testing purposes. Copyright (C) 1999 by W.B. Saunders Company.