The purpose of this study was to identify the most common direct oral anticoagulant (DOAC) agent associated with breakthrough ischaemic strokes amongst patients on DOAC therapy for non-valvular atrial fibrillation(NVAF), taking into account the different prescribing regimens between DOACs available in Australia. 

DOACs were approved for stroke prevention in NVAF in 2010. Guidelines have increasingly favoured this therapy amongst suitable patients over Warfarin due to its easier prescribing regimen and superior safety profile. However, despite similar elimination kinetics the dosing frequency differ amongst the agents: twice daily for Dabigatran and Apixaban while once daily for Rivaroxaban. Comparison of efficacy between these agents is limited due to significant study population differences between landmark DOAC trials. 

This was a retrospective review of all patients presenting to a tertiary hospital stroke unit in Queensland, Australia from January 2015 to June 2018. Patients were included if they sustained an ischaemic stroke whilst on DOAC for NVAF. DOAC agent, patient compliance and outcomes of admission were documented. Patients who had a recent cessation of DOAC and their indications were also acknowledged.

A total of 42 patients sustained an ischaemic stroke whilst on DOAC therapy. 5 patients were deemed to be non-compliant while 5 patients had DOAC therapy commenced within one week prior to presentation. 74% of the identified cohort with a breakthrough stroke were on Rivaroxaban , 12% were on Apixaban and 14% on Dabigatran. A further 14 patients had DOAC recently ceased, most commonly pre-procedure, leading to an ischaemic stroke. 

This study highlights the disproportionate number of breakthrough strokes amongst patients on Rivaroxaban for NVAF, raising the concern for inadequate stroke prevention within this cohort. This study also acknowledges the importance of physician awareness for bridging anticoagulation prior to procedures to minimize risks of ischaemic strokes.