Clinical application of viscoelastic point-of-care tests of coagulation-shifting paradigms

Abstract

Bleeding during cardiac surgery, liver transplant, trauma and post partum hemorrhage are often multifactorial and these factors are dynamic as new factors crop up during the course of management. Conventional tests of coagulation offer information of a part of the coagulation system and also is time consuming. Viscoelastic point of care tests (VE POCTs) like rotational thromboelastometry, thromboelastogram and Sonoclot, are based on analysis of the viscoelastic properties of clotting blood and provide information for the entire coagulation pathway. In this comprehensive review being presented here, we have examined the pros and cons of VE POCTs including clinical, cost and survival benefits. The recommendations of the various guidelines regarding use of VE POCTs in various scenarios have been discussed. The review also tried to offer suggestions as to their optimal role in management of bleeding during cardiac surgeries, extracorporeal membrane oxygenation, left ventricular assist devices, liver transplant and briefly in trauma and postpartum hemorrhage.

Anticoagulation Management in V-V ECMO Patients: A Multidisciplinary Pragmatic Protocol

“…VETs are point-of-care tests on whole blood samples used when fast and goal-directed therapy is needed. These are qualitative tests that can monitor global hemostasis, giving information regarding clot formation, stability, and lysis; hypercoagulability (eventually predicting thrombotic risk); hypo or hyperfibrinolysis [15].…”

“…It is also possible to measure the anticoagulation effect with UFH in a semi-quantitative manner using two simultaneous specific tests (e.g., INTEM and HEPTEM in rotational thromboelastometry). There are randomized controlled trials regarding VET usage in ECMO patients that show a good predictive value for hemorrhage and thrombosis, being a valuable test for UFH anticoagulation monitoring in ECMO or left ventricular assist device (LVAD) [13,15].…”

“…VET devices require calibration at regular intervals and skilled operators [15]. The sensitivity of the reagents differs between different manufacturers and sets of reagents [15]. We suggest a VET analysis as part of a multimodal coagulation management protocol.…”

Evaluation of Blood Coagulation by Optical Vortex Tracking

“…Currently, the primary clinical devices that can monitor the coagulation dynamics process are thrombelastography (TEG) and rotational thrombelastography (ROTEM). They evaluate the viscoelastic properties of a blood sample by applying a continuous oscillation to it and bringing it into contact with a metal wire to assess the formation, stabilization, and ultimately dissolution process [13][14][15][16]. While they overcome the drawbacks of CCTs, such as being unable to continuously monitor the whole process of coagulation, TEG and ROTEM, based on blood contact and mechanical excitation, delay clot formation and affect clot structure during measurements, leading to inaccurate coagulation results [15].…”

“…They evaluate the viscoelastic properties of a blood sample by applying a continuous oscillation to it and bringing it into contact with a metal wire to assess the formation, stabilization, and ultimately dissolution process [13][14][15][16]. While they overcome the drawbacks of CCTs, such as being unable to continuously monitor the whole process of coagulation, TEG and ROTEM, based on blood contact and mechanical excitation, delay clot formation and affect clot structure during measurements, leading to inaccurate coagulation results [15]. TEG and ROTEM are also less operable, more difficult to maintain, and more expensive due to their sophisticated components and complex construction.…”