Considerable variability in randomly timed DOAC concentrations was observed before elective electrical cardioversion, with dosing discrepancies that highlight the importance of periodically reassessing prescribed doses against current patient characteristics.
Key Findings
Results
In 37 AF patients on rivaroxaban, dabigatran, or edoxaban before elective ECV, DOAC plasma concentrations varied considerably when sampled irrespective of dose timing.
Cross-sectional study of adult AF patients scheduled for elective electrical cardioversion.
Blood samples were collected before the procedure regardless of when the DOAC was last taken.
Concentrations were measured with drug-specific chromogenic assays and compared descriptively with guideline expected peak and trough ranges.
Results
Ten of 37 measurements (27.0%) exceeded the upper bounds of the expected peak concentration distributions.
The abstract reports "Ten measurements (27.0%) exceeded the upper bounds of expected peak concentration distributions."
Comparisons with expected distributions were descriptive only, with no formal statistical testing.
Results
Two measurements (5.4%) fell below the lower bounds of the expected trough distributions.
The abstract reports "two measurements (5.4%) fell below the lower bounds of trough distributions."
Samples were randomly timed relative to dosing, which limits interpretation against peak/trough references.
Results
Polypharmacy was highly prevalent in the study population.
Polypharmacy was observed in 83.8% of the 37 participants.
The authors note possible drug-drug interactions as a source of concentration variability.
Results
Two patients were receiving standard DOAC doses despite meeting renal criteria for dose reduction.
This dosing discrepancy was identified when prescribed doses were compared with patient characteristics.
The authors conclude that periodically reassessing prescribed doses against current patient characteristics is important.
Conclusions
The authors conclude that larger prospective studies with standardized sampling and clinical follow-up are needed to clarify the clinical significance of the findings.
The study was small (n=37), cross-sectional, and used non-standardized sampling times.
Comparisons to guideline ranges were descriptive reference points only, and no clinical outcomes were linked to concentrations.
What This Means
People with atrial fibrillation who undergo electrical cardioversion to restore a normal heart rhythm need to take blood thinners without interruption to lower the risk of stroke. Newer blood thinners (DOACs) are often assumed to work predictably, so blood levels are rarely checked. This small study measured DOAC levels in 37 patients just before a planned cardioversion.
Blood levels varied considerably. About a quarter of measurements (10 of 37) were above the expected peak range, and 2 were below the expected trough range. Most patients (about 84%) took multiple medications, which could affect drug levels. Two patients were on a standard dose even though their kidney function met criteria for a lower dose. Because blood was drawn at random times relative to the last dose, the comparison with expected ranges is only rough.
This research suggests that checking whether a patient's DOAC dose still fits their current characteristics, such as kidney function, may be worthwhile. The study was small, did not follow patients for outcomes, and cannot show whether the variation affects safety or effectiveness. Larger studies with standardized blood sampling and follow-up are needed.
Ņikitina A, Urtāne I, Siļčonoks D, Meisters J, Latkovskis G, Gavrilova A. (2026). Assessment of Direct Oral Anticoagulant Plasma Concentrations Before Elective Electrical Cardioversion.. Medicina (Kaunas, Lithuania). https://doi.org/10.3390/medicina62102007