Related Experiment Video
Updated: May 9, 2026
In Vitro Thrombosis Test for Ventricular Assist Devices
Published on: March 21, 2025
Validation of rotational thromboelastometry during cardiopulmonary bypass: A prospective, observational in-vivo study
Fabrizio Gronchi1, Anouk Perret, Enrico Ferrari
1From the Department of Anaesthesiology (FG, AP, CMM, PS, CM), Department of Cardiac Surgery (EF, JF, MC), Lausanne University Hospital, Lausanne, Switzerland.
Background:
Rotational thromboelastometry (ROTEM) is a whole blood point-of-test used to assess the patient's coagulation status. Three of the available ROTEM tests are EXTEM, INTEM and HEPTEM. In the latter, heparinase added to the INTEM reagent inactivates heparin to reveal residual heparin effect. Performing ROTEM analysis during cardiopulmonary bypass (CPB) might allow the anaesthesiologist to anticipate the need for blood products.
Objective:
The goal of this study was to validate ROTEM analysis in the presence of very high heparin concentrations during CPB.
Design:
Prospective, observational trial.
Setting:
Single University Hospital.
Participants:
Twenty patients undergoing coronary artery bypass grafting.
Main Outcome Measure:
ROTEM analysis was performed before heparin administration (T0), 10 min after heparin (T1), at the end of CPB (T2) and 10 min after protamine (T3). The following tests were performed: EXTEM, INTEM, and HEPTEM. Heparin concentrations were measured at T1 and at the end of bypass (T2).
Results:
At T1, EXTEM differed from baseline for coagulation time: +26.7 s (18.4 to 34.9, P < 0.0001), α: -3° (1.0 to 5.4, P = 0.006) and A10: -4.4 mm (2.3 to 6.5, P = 0.0004). INTEM at T0 was different from HEPTEM at T1 for coagulation time: + 47 s (34.3 to 59.6, P > 0.0001), A10: -2.3 mm (0.5 to 4.0, P = 0.01) and α -2° (1.0 to 3.0; P = 0.0007). At T2, all parameters in EXTEM and HEPTEM related to fibrin-platelet interaction deteriorated significantly compared to T1. At T3, EXTEM and INTEM were comparable to EXTEM and HEPTEM at T2.
Conclusion:
HEPTEM and EXTEM measurements are valid in the presence of very high heparin concentrations and can be performed before protamine administration in patients undergoing cardiac surgery with CPB.
Trial Registration:
clinicaltrials.gov Identifier: NCT01455454.
