Managing Ischemic Stroke in Patients Already on Anticoagulation for Atrial Fibrillation: A Nationwide Practice Survey

Characteristics of Ischemic Stroke Despite Oral Anticoagulant Use For Atrial Fibrillation

Oral anticoagulation (OAC) prevents stroke in atrial fibrillation, yet a residual stroke risk remains. In this single-center retrospective analysis of acute ischemic stroke patients despite OAC, suboptimal OAC treatment is common (30%: inappropriate dosing (17%); patient non-adherence (13%)). Other causes of stroke included OAC interruption (14.5%), a competing stroke mechanism (11.0%), and undetermined breakthrough stroke in 44.5%. Overall, easily modifiable causes of ischemic stroke despite OAC are common. Accordingly, strategies to improve treatment compliance, including appropriate dosing along with guideline-based risk factor and periprocedural OAC management, should be emphasized to improve secondary stroke prevention in this patient population.

Oral anticoagulant switching in patients with atrial fibrillation: a scoping review

INTRODUCTION

Oral anticoagulants (OACs) prevent stroke in patients with atrial fibrillation (AF). Several factors may cause OAC switching.

OBJECTIVES

To examine the phenomenon of OAC switching in patients with AF, including all available evidence; frequency and patterns of switch, clinical outcomes, adherence, patient-reported outcomes, reasons for switch, factors associated with switch and evidence gaps.

DESIGN

Scoping review.

DATA SOURCES

MEDLINE, Embase and Web of Science, up to January 2022.

RESULTS

Of the 116 included studies, 2/3 examined vitamin K antagonist (VKA) to direct-acting OAC (DOAC) switching. Overall, OAC switching was common and the definition of an OAC switch varied across. Switching from VKA to dabigatran was the most prevalent switch type, but VKA to apixaban has increased in recent years. Patients on DOAC switched more to warfarin than to other DOACs. OAC doses involved in the switches were hardly reported and patients were often censored after the first switch. Switching back to a previously taken OAC (frequently warfarin) occurred in 5%-21% of switchers.The risk of ischaemic stroke and gastrointestinal bleeding in VKA to DOAC switchers compared with non-switchers was conflicting, while there was no difference in the risk of other types of bleeding. The risk of ischaemic stroke in switchers from DOAC versus non-switchers was conflicting. Studies evaluating adherence found no significant changes in adherence after switching from VKA to DOAC, however, an increase in satisfaction with therapy were reported. Reasons for OAC switch, and factors associated with OAC switch were mostly risk factors for stroke and bleeding. Clinical outcomes, adherence and patient-reported outcomes were sparse for switches from DOACs.

CONCLUSIONS

OAC switching is common in patients with AF and patients often switch back to an OAC they have previously been on. There are aspects of OAC switching that have received little study, especially in switches from DOACs.

Ischemic stroke in oral anticoagulated patients with atrial fibrillation

BACKGROUND

Ischemic strokes in orally anticoagulated patients pose challenges for acute management and secondary prevention but the characteristics of these strokes are poorly understood. We examined the clinical and imaging features, the presumed underlying etiology and the subsequent antithrombotic management.

METHODS

We analyzed a consecutive series of patients enrolled into the EIDASAF study, a single center, observational study of ischemic stroke patients with a diagnosis atrial fibrillation (AF) prior to the index event who had been admitted to the Hyperacute Stroke Unit of Imperial College London between 2010 and 2017. We compared patients with oral anticoagulation therapy prior admission (OAC_prior ) with those without anticoagulation (OAC_naive ). Brain imaging was analyzed centrally.

RESULTS

763 patients were included in the analysis. 481 (63%) were OAC_naive while 282 (37%) were OAC_prior . Patients with OAC_prior were younger, more often had a previous history of stroke or transient ischemic attack (TIA), and more often suffered from hypertension and diabetes. In OAC_naive, patients, large and deep middle cerebral artery infarcts occurred more often than in OAC_prior patients. The groups differed significantly in the distribution of competing etiologies underlying their stroke. At discharge, OAC_prior more frequently were (re)-anticoagulated compared to OAC_naive patients. Within the OAC_prior group, patients with recurrent strokes did not differ from those with a first stroke regarding clinical characteristics and pattern of cerebral infarction but they were less frequently anticoagulated.

CONCLUSIONS

Ischemic strokes on OAC represent a significant proportion of AF-related strokes. There is an unmet need to better understand the causes underlying these strokes and to optimize the medical management.