A novel optical sensor contained within a small hand-held device called iCoagLab was able to accurately measure anticoagulation and global hemostasis in patients during cardiac surgery with cardiopulmonary bypass (CPB) using a drop of blood, allowing multifunctional coagulation/dose-response monitoring to high-dosages of heparin during surgery.
Results of a study evaluating the accuracy and sensitivity of the device were presented by Diane Malu Tshikudi, MS, and colleagues of the Wellman Center for Photomedicine, Massachusetts General Hospital, and Harvard Medical School in Boston, at the Thrombosis & Hemostasis Summit of North America (THSNA) 2020 Virtual Conference.
“An estimated 20% [of] patients suffer from excessive bleeding post-surgery that can require transfusion of blood products,” wrote the investigators. “This underscores the need for tools to accurately monitor heparin dosage, protamine concentration, and patients’ coagulation status perioperatively and at point-of-care.”
In the study, several coagulation parameters were assessed using the iCoagLab, including activated clotting time (ACT), clot progression rate/fibrin polymerization (α-angle), and clot strength (MA) and the tool’s capability to monitor anticoagulation during cardiac surgery. These parameters were also measured using conventional thromboelastography (TEG), i-STAT kaolin ACT, and Hepcon HMS Plus instruments for correlation and comparison. Of note, according to the authors, the hand-held iCoagLab device requires only 25µL of whole blood and produces results within minutes.
To test device performance, the team used whole blood samples from 18 healthy volunteers; the samples were spiked with heparin (1-5 USP/mL) and subsequently with protamine (30-90 µg/mL) to neutralize heparin. Clinical testing during cardiac surgery was conducted using whole blood samples from 30 patients. Samples were assessed at 6 timepoints during surgery: at baseline, after heparin administration, before CPB, after CPB, before protamine administration, and after protamine reversal.
In the device performance testing, addition of heparin significantly prolonged the ACT measured by iCoagLab, and the iCoaglab ACTs were strongly correlated with those of TEG (r=.91; P <.0001) and i-STAT ACT (r=.78; P <.0001). At high heparin doses, like TEG, the iCoagLab device measured decreasing MA (P <.01). In all the cases, addition of protamine significantly reversed effects of heparin (2 USP/mL), shortening the ACTs measured by the iCoagLab, TEG, and i-STAT kaolin ACT and restoring α-angle and MA values measured by the iCoagLab and TEG back to baseline values.
Among the 6 timepoint samples from the patients undergoing cardiac surgery, the iCoagLab ACT was strongly correlated with the TEG ACT (r=.87; P <.0001) and moderately correlated with the Hepcon ACT (r=.76; P <.0001). The iCoagLab and TEG values for MA (r=.71; P <.001) and α-angle (r=.68; P <.0001) were also moderately correlated.
“We successfully monitor[ed] cardiac surgery patients’ coagulation status using the iCoagLab technology,” concluded the authors. “The iCoagLab rapidly and accurately measures anticoagulation and protamine reversal in patients during CPB in 25 µL of blood, likely opening the opportunity for multifunctional coagulation monitoring at the point of care.”
Tshikudi DM, Wirth A, Andrawes MN, Nadkami S. Point-of-care coagulation monitoring using a novel optical sensor in patients undergoing cardiac surgery. Abstract presented at: THSNA 2020 Thrombosis & Hemostasis Summit of North America; October 27-30, 2020. Abstract 12.