Abstract
Background
Patients prescribed oral anticoagulants (OAC) for atrial fibrillation (AF) can still present with stroke. The mechanism for stroke in these patients can be due to multiple factors including subtherapeutic dosing and non-compliance. With the increasing use of direct-acting OACs (DOACs) in favour of warfarin, it is unclear if the incidence of stroke in those already taking OAC has reduced.
Methods
Data was extracted from our unit’s stroke registry, a prospectively maintained database, for patients who presented with stroke while receiving OAC for AF from 2013 to 2017. Type of OAC, type of stroke, OAC dosing at time of event including non-compliance, stroke management and outcome were recorded.
Results
67 patients were included for analysis, with 55 ischaemic and 12 haemorrhagic strokes. 52 patients were receiving warfarin at the time of their stroke vs. 15 receiving DOACs. 33/55 (60%) of ischaemic strokes occurred in patients taking warfarin with a sub-therapeutic INR. In 3/55 (5%) of ischaemic strokes, the OAC was held for a procedure while in 6/55 cases (11%) the OAC had been stopped for another reasons e.g. bleeding. 5/55 (7%) were due to non-compliance. 1 ischaemic stroke was due to under-dosing of a DOAC (dabigatran). 16 strokes were recorded in 2013 for patients prescribed OAC vs. 3 in 2017. Overall the number of ischaemic strokes due to subtherapeutic OAC decreased from 14 in 2013 to 1 in 2017 (p value 0.06).
Conclusion
The majority of strokes occurring in anticoagulated patients are related to warfarin use. We observed an almost significant reduction in the proportion of ischaemic strokes due to under-dosing of OAC over the study period. Warfarin continues to be recommended as the first line anticoagulant for stroke prevention in atrial fibrillation by the HSE Medicines Management Programme, a decision which we would argue warrants review.
306 The Changing Face of Stroke in the DOAC Era