PHILADELPHIA – A disproportionate number of breakthrough strokes were observed among patients receiving rivaroxaban for nonvalvular atrial fibrillation in a stroke unit, according to a small, single-center, retrospective study presented at the annual meeting of the American Academy of Neurology.
The researchers reviewed all patients presenting to a tertiary care stroke unit in Australia from January 2015 to June 2018.
A total of 56 patients (median age was 74 years; 61% were male) had received direct oral anticoagulant (DOAC) therapy and then had an ischemic stroke. Of those patients, 37 (66%) had strokes while receiving the treatment; 14 patients (25%) had a stroke after recently stopping a DOAC, often prior to a medical procedure; and 5 patients (9%) were not adherent to their DOAC regimen.
Of the 37 patients who had strokes during DOAC treatment, 48% were on rivaroxaban, 9% were on dabigatran, and 9% were on apixaban, Fiona Chan, MD, of The Princess Alexandra Hospital, Brisbane, Australia, and coinvestigators reported in a poster presentation.
While these findings need to be replicated in a larger study, they do “raise concern for inadequate stroke prevention within this cohort,” they said.
Moreover, the findings illustrate the importance of bridging anticoagulation prior to procedures, when appropriate, to minimize stroke risk, they added, as 25% of the strokes had occurred in patients who recently stopped the DOACs due to procedures.
To determine which DOAC was most often associated with breakthrough ischemic strokes in patients with nonvalvular atrial fibrillation, the investigators compared the proportion of DOACs prescribed in Australia to the proportion of observed strokes in their cohort.
Despite accounting for about 51% of Australian DOAC prescriptions, rivaroxaban represented nearly 73% of breakthrough strokes among the patients who had strokes while receiving the treatment (P = .001), the investigators reported.
Conversely, apixaban accounted for about 35% of prescriptions but 14% of the breakthrough strokes (P = .0007), while dabigatran accounted for 14% of prescriptions and 14% of the strokes (P = 0.99), the investigators said in their poster.
One limitation of this retrospective study is that the patient cohort came from a single specialized center, and may not reflect the true incidence of nonvalvular atrial fibrillation across Australia, the researchers noted.
Dr. Chan and coinvestigators reported that they had no relevant financial disclosures.
SOURCE: Chan F et al. AAN 2019. .