Background: The Quantra Hemostasis Analyzer is a novel diagnostic device that uses an ultrasound-based technology, sonic estimation of elasticity via resonance (SEER) sonorheometry, to characterize the dynamic changes in viscoelastic properties of a blood sample during coagulation. Cardiac surgery utilizing cardiopulmonary bypass (CPB) is associated with a significant impact on the coagulation system and can result in perioperative coagulopathy. The aim of this study was to correlate SEER sonorheometry results to corresponding rotational thromboelastometry (ROTEM) and laboratory parameters obtained before, during, and after CPB.
Methods: The Quantra uses a multiwell cartridge that performs 4 independent measurements with different combination of reagents. The output test results include Clot Time, Clot Stiffness, Fibrinogen and Platelet Contribution, Clot Time Ratio, and Heparinase Clot Time. Clot Time was compared with ROTEM INTEM clotting time and the adjusted partial thromboplastin time. Clot Stiffness was compared with ROTEM EXTEM. The Fibrinogen Contribution to the Clot Stiffness was correlated to ROTEM FIBTEM as well as fibrinogen concentration by the Clauss method. The Platelet Contribution to Clot Stiffness was compared with absolute platelet count and ROTEM-determined clot elasticity attributable to platelets.
Results: Fifty-five patients undergoing elective cardiac surgery were enrolled in this prospective observational study. Clot Time exhibited good correlation with ROTEM INTEM clotting time (pre-CPB r = 0.84, post-CPB r = 0.65) and adjusted partial thromboplastin time (pre-CPB r = 0.72, post-CPB r = 0.89); however, the majority of values were within a narrow normal range. Clot Stiffness exhibited significant correlation with ROTEM EXTEM A10 throughout the course of the study in all samples (r = 0.84). Fibrinogen Contribution correlated strongly with FIBTEM A10 (r = 0.85), and moderately with the fibrinogen concentration (r = 0.73) determined with the Clauss assay. The Platelet Contribution to Clot Stiffness showed moderate correlation to absolute platelet counts (r = 0.48). However, the correlation between Platelet Contribution and ROTEM-determined clot elasticity attributable to platelets was stronger (r = 0.78) than platelet number. All of the correlation coefficients were statistically significant with P < .001.
Conclusions: SEER sonorheometry demonstrates significant correlation with ROTEM for determining Clot Stiffness and assessing Fibrinogen Contribution. SEER sonorheometry results can provide valuable information about the coagulation status in patients undergoing cardiac surgery using CPB.