An introduction to point-of-care testing in extracorporeal circulation and LVADs

Abstract

There is a delicate balance between bleeding and clotting in patients on circuits such as ventricular assist devices or extracorporeal membrane oxygenation. Traditional coagulation tests, prothrombin time, activated partial thromboplastin time, and anti-factor Xa levels, are used to monitor patients on these devices. However, turnaround times and inability to assess global hemostasis, including platelets and fibrinogen have contributed to a recognition that faster, accurate, and more informative coagulation tests are needed. Activated clotting time is used to monitor heparin in patients on circuits and has the advantages of being a near-patient point-of-care test. However, its utility is limited to heparin monitoring. Viscoelastic tests (thromboelastometry and thromboelastography) are global, whole-blood coagulation tests, and whole-blood platelet aggregometry evaluates platelet function. Ideally, these tests can ensure that patients are within the therapeutic range of their antithrombotic medications, identify patients at risk for hemorrhagic or thrombotic complications, and guide management of acute bleeding complications. This ideal is currently hampered by a lack of studies that delineate clear ranges that are clinically relevant. Future research is needed to better understand the optimal use of point-of-care coagulation testing in patients on extracorporeal circuits and ventricular assist devices.

Improving ECMO therapy: Monitoring oxygenator functionality and identifying key indicators, factors, and considerations for changeout

“…However, there is a need for long-term follow-up studies to assess the impact of change-outs on patient survival, organ function, and quality of life. Understanding the long-term consequences and potential complications associated with change-outs can guide decision-making and improve patient counseling and care [25,36,37,38,39,40].…”

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

“…ECMO and LVAD provide critical support to patients with life threatening cardiac or pulmonary failure. [ 33 ] Management of anticoagulation in patients with ECMO or LVAD is a tight rope walk as both bleeding (5-81%) and thrombotic (about 18%) complications are common. [ 34 ] Unfractionated heparin (UFH) is the most common anticoagulant in circuits.…”

“…[ 34 ] Unfractionated heparin (UFH) is the most common anticoagulant in circuits. [ 33 ] In patients with LVAD, antiplatelet agents are also part of therapeutic regime. [ 33 ] Patients on LVADs used as destination therapy are frequently managed with LMWH or vitamin K antagonist (VKA).…”

“…[ 33 ] In patients with LVAD, antiplatelet agents are also part of therapeutic regime. [ 33 ] Patients on LVADs used as destination therapy are frequently managed with LMWH or vitamin K antagonist (VKA). [ 33 ] As of now, the standard practice in most of the centres manging LVADs is to use of APTT to monitor UFH, anti-Xa assay to monitor action of LMWH and INR to monitor VKA.…”

“…[ 36 ] To date, there have been no randomized multi-institutional trials comparing TEG or ROTEM with APTT, PT/INR, or anti-Xa levels for monitoring and dose adjustment of anticoagulation and antiplatelet medications in such patients. [ 33 ] Colman E et al (2019) retrospectively compared patients on ECMO whose bleeding was managed either with APTT alone or in combination with TEG. They reported that incidence of major bleeding did not differ between the two groups, whereas the mortality and incidences of retroperitoneal bleeding were less in the group managed with TEG.…”