A level‐headed approach to measuring direct oral anticoagulants: A 2‐year retrospective analysis of DOAC levels from a tertiary UK centre

Abstract

Introduction Direct oral anticoagulants (DOAC) are commonly prescribed and measuring drug levels may be useful in a number of contexts. However, data on DOAC level measurement and their clinical utility in real‐world studies are limited. Methods We carried out a 2‐year retrospective cohort study of DOAC levels measured at our institution. Results One hundred and sixty‐nine levels measured in 113 patients were included in the final analysis. Our patients had a median age of 69.9. AF was the commonest indication for anticoagulation. Median turnaround time for inpatient levels was 92 minutes. Median FXa inhibitor levels within 6 hours of last dose and following one half‐life were similar to those described previously. However, the range of levels was wider than expected. Importantly, some levels remained in an on therapy range even after 3 half‐lives. There was no correlation between dabigatran level and time from last dose. The reason for request varied with setting; 23 outpatient levels were to monitor drug efficacy, whereas 54 and 43 inpatient levels were collected in the context of bleeding and emergency surgery respectively. 60.3% of levels had an impact on clinical decision making. Conclusion Our real‐world study demonstrates that DOAC levels can be performed in a timely manner to influence clinical decision making. In addition, it suggests there is a wide variation in levels such that it can be difficult to predict in the real world. Overall, this supports the wider use of DOAC levels to help guide clinicians in managing patients taking these drugs.

Evaluation of Anti-Xa Apixaban and Rivaroxaban Levels With Respect to Known Doses in Relation to Major Bleeding Events

“…Recent studies with more dynamic patient populations have noted higher interindividual variability in anti-Xa levels at any given time point, which further challenges the need for established therapeutic ranges. 48,49 Though our study findings explore potential use of anti-Xa level monitoring for safe anticoagulation practices in the interim, they are not intended to suggest deviation from current guideline-based clinical practice. More data is needed as challenges remain with anti-Xa level interpretation and subsequent long-term clinical-decision making.…”

Is It Really Safe to Discontinue Anticoagulant Treatment Before Ptosis Surgery From Serious Bleeding?

“…Second, the action of ACs/APs would have persisted even when the AC was discontinued. Two studies 15,16 reported residual serum concentrations of ACs/ APs in patients who underwent elective invasive procedures. Anne et al 15 confirmed persistent AC effects in most patients even after discontinuing for 3 times the half-life of the known AC.…”

Is It Really Safe to Discontinue Anticoagulant Treatment Before Ptosis Surgery From Serious Bleeding?

“…Second, the anticoagulant action would have persisted even when the anticoagulant was discontinued. Two studies [16,17] reported residual serum concentrations of anticoagulants in patients who underwent elective invasive procedures. Anne et al [16] con rmed persistent anticoagulant effects in most patients even after discontinuing for 3 times the halflife of the known anticoagulant.…”