[Perioperative anticoagulation with NOAC using the example of rivaroxaban]

The methods for removal of direct oral anticoagulants and heparins to improve the monitoring of hemostasis: a narrative literature review

The assessment of hemostasis is necessary to make suitable decisions on the management of patients with thrombotic disorders. In some clinical situations, for example, during thrombophilia screening, the presence of anticoagulants in sample makes diagnosis impossible. Various elimination methods may overcome anticoagulant interference. DOAC-Stop, DOAC-Remove and DOAC Filter are available methods to remove direct oral anticoagulants in diagnostic tests, although there are still reports on their incomplete efficacy in several assays. The new antidotes for direct oral anticoagulants - idarucizumab and andexanet alfa - could be potentially useful, but have their drawbacks. The necessity to remove heparins is also arising as heparin contamination from central venous catheter or therapy with heparin disturbs the appropriate hemostasis assessment. Heparinase and polybrene are already present in commercial reagents but a fully-effective neutralizer is still a challenge for researchers, thus promising candidates remain in the research phase.

Monitoring of Anticoagulant Activity of Dabigatran and Rivaroxaban in the Presence of Heparins

The routine monitoring of direct oral anticoagulants (DOACs) may be considered in patients with renal impairment, patients who are heavily obese, or patients requiring elective surgery. Using the heparin-binding copolymer (HBC) and polybrene, we aimed to develop a solution for monitoring the anticoagulant activity of DOACs in human plasma in the interfering presence of unfractionated heparin (UFH) and enoxaparin. The thrombin time (TT) and anti-factor Xa activity were monitored in pooled plasma from healthy volunteers. In these tests, plasma with dabigatran or rivaroxaban was mixed with UFH or enoxaparin and then incubated with HBC or polybrene, respectively. HBC and polybrene neutralized heparins and enabled monitoring of anticoagulant activity of dabigatran in the TT test. Both agents allowed for accurate measurement of anti-factor Xa activity in the plasma containing rivaroxaban and heparins in the concentration range reached in patients’ blood. Here, we present diagnostic tools that may improve the control of anticoagulation by eliminating the contamination of blood samples with heparins and enabling the monitoring of DOACs’ activity.

[Peri-Interventional Management of Direct Oral Anticoagulants - Balancing Benefits and Risks]

Zusammenfassung. Das periprozedurale Management von direkten oralen Antikoagulanzien löst bei vielen Klinikern noch Unsicherheit aus. Dies mag daran liegen, dass mit Apixaban, Dabigatran, Edoxaban und Rivaroxaban Substanzen mit unterschiedlichen Wirkansätzen und Pharmakokinetik auf dem Markt vertreten sind. Der Umgang mit DOAK bedarf einer individuellen Risikoeinschätzung betreffend Blutungen und Thromboembolien, insbesondere im perioperativen/periinterventionellen Management. Ein Therapie-Monitoring ist im Regelfall nicht erforderlich. Situativ kann die Bestimmung der Serumkonzentration von Interesse sein. Es stehen für die einzelnen Substanzen hierfür unterschiedliche Verfahren zur Verfügung. Die Möglichkeit einer Verfälschung weiterer Gerinnungsmarker muss berücksichtigt werden. Im Falle einer schweren Blutungskomplikation muss PPSB angewendet werden. Das einzige bisweilen verfügbare Antidot stellt Praxbind® (Idarucizumab) dar. Aktuelle Forschungsergebnisse lassen aber mutmassen, dass zukünftig weitere Therapieoptionen auch für Substanzen, welche den Faktor Xa hemmen, bald zur Verfügung stehen werden.