An international consensus on managing new oral anticoagulants in patients having cardiac surgery provides pertinent information that will enlighten their use outside cardiac surgery also.
Measurement of DOACS may be useful in emergencies or uncertainty, or in significant renal or hepatic dysfunction; however, such measurement as well as routine coagulation testing is not recommended. Greater caution is also needed in the elderly. Dabigatran is particularly dependent on renal function.
Normal prothrombin time or activated partial thromboplastin time results exclude excess levels of dabigatran, rivaroxaban and edoxaban, but not apixaban. Normal thrombin time precludes significant dabigatran plasma levels, and the aPTT shows some correlation here also – for precise measurements, the diluted thrombin time (dTT), the ecarin clotting time or the ecarin chromogenic assay may be used. For the precise measurement of drug concentrations of all FXa inhibitors, chromogenic and calibrated anti‐FXa tests are recommended.
Reversal agents: for dabigatran, idarucizumab is available; for the FXa inhibitors, andexanet alpha has been approved in the US, and ciraparantag is currently under investigation. Ultrafiltration and Hemodialysis are also discussed for Dabigatran, and non-specific approaches of varying efficacy include prothrombin complex concentrate, fibrinogen concentrate, tranexamic acid and/or factor VIIa.
In general, withholding for 2 days is appropriate. For Dabigatran, this may need 3-5 days depending on renal function. Resumption at therapeutic doses is recommended after 2-3 days and after removal of chest drains. (In the non-cardiac surgery setting, resumption may be sooner depending on bleeding risk). Prophylactic doses may be needed sooner after surgery for thromboembolic prophylaxis. Bridging agents are not recommended for interruptions less than 4 days, as increased bleeding without lower thromboembolism is reported. Individualized approaches may be needed based on CHA2DS2‐VASc Score and bleeding risk.
From an anesthesia perspective, neuraxial anesthesia performance should be equated with high bleeding risk and longer interruption may be the preferred – the ASRA provides one such set of guidelines.