Anticoagulation and hemostasis monitoring during cardiac surgery with a drop of whole blood using a novel optical sensor

Abstract

Cardiac surgical patients with cardiopulmonary bypass receive large heparin doses to prevent thrombosis during surgery. Activated clotting time (ACT), used to assess anticoagulation, correlates poorly with heparin plasma concentration and lacks information on key coagulation metrics such as fibrin polymerization (α-angle) and clot strength (MA). Here we assess the accuracy and measurement sensibility of our novel optical sensor, iCoagLab, in measuring several coagulation parameters including ACT, α-angle and MA and evaluate its capability to monitor anticoagulation during cardiac surgery. iCoagLab measures anticoagulation by assessing changes in blood viscosity from intensity fluctuations of laser speckle patterns measured from 25μL of blood sample. In this study, blood samples from 9 volunteers spiked with increased concentrations of heparin (1-5USP/mL) and from 30 patients undergoing cardiac surgery were assessed using iCoagLab. Coagulation parameters, including, ACT, α-angle and MA, were extracted and compared with corresponding results obtained from thromboelastography (TEG), ISTAT-kaolin-ACT and Hepcon-HMS-Plus-instruments. In volunteer samples, heparin treatment significantly prolonged the ACT values measured by iCoagLab which correlated closely with TEG (r=0.91, p<0.0001) and ISTAT-ACT (r=0.78, p<0.0001). At high heparin dose, both the iCoagLab and TEG presented a decrease in MA (p<0.01). Similarly, in cardiac surgical samples, iCoagLab-ACT highly correlated with Hepcon (r=0.76 p<0.0001) and TEG-ACT (r=0.86, p<0.0001). Furthermore, the iCoagLab and TEG MA and α-angle were also significantly modulated by surgery (p<0.05-0.0001). In conclusion, iCoagLab accurately measured anticoagulation and global hemostasis using a drop of blood, likely opening the unique opportunity for multifunctional coagulation monitoring at the point-of care during cardiac surgery.