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) and 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 heparin concentrations tested by anti-Xa activity. A secondary objective was to 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 consent were obtained, adult patients undergoing cardiac or peripheral vascular surgery were included in this study. Interventions: In both surgical groups, blood was sampled for ACT, HMT, and anti-Xa activity. Each HMT was performed on both noncitrated and citrated samples, Measurements and Main Results: As an indicator of heparin effect, the HMI had a strong correlation with the ACT (r = 0.899; P < 0.01). In addition, the HMT had a significantly stronger correlation with anti-Xa activity than the ACT (p < 0.01). The correlation obtained from the noncitrated samples was 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 similar to citrated HMT results, thus supporting the use of fresh whole blood for testing purposes. Copyright (C) 1999 by W.B. Saunders Company.