This large prospective cohort study contained 2,162 consecutive patients from the Ontario Stroke Registry between July 2003 and March 2008 who were hospitalized with acute ischemic stroke and atrial fibrillation. It sought to examine the relationship between antithrombotic regimen upon discharge and the ensuing risk of major vascular events as well as major bleeding on follow up, giving particular attention to patients with severe stroke as well as those with coronary heart disease. The primary outcomes included death or hospital readmission for recurrent stroke, myocardial infarction, or major bleeding while secondary outcomes included hospital admission for stroke, myocardial infarction, major bleeding, intracerebral hemorrhage, all cause mortality, and a combination of these outcomes. Among the 2162 patients with atrial fibrillation, 8% were discharged without any antithrombotic therapy, 21.6% were prescribed antiplatelets alone, 39.3% were prescribed anticoagulation alone, and 31.1% were prescribed combination therapy with anticoagulation and antiplatelet. Comparing populations, it was seen that actual management of these patients differed, and patients with a higher risk of bleeding were less likely to be prescribed anticoagulation while patients discharged on combination therapy had a higher cardiovascular risk profile and higher risk of severe strokes.

After statistical analysis, it was discovered that combination anticoagulation and antiplatelet were associated with a trend towards a reduced risk of the primary outcome while no antithrombotic therapy or antiplatelet therapy alone were associated with an increased risk. Those patients not given antithrombotic therapy or given antiplatelet therapy alone were associated with a reduced risk of admission for major bleeding while combination therapy was associated with an increased risk. Of note, there was not an association with increased risk of admission for ICH over the four years on those patients with combination therapy. In assessing those patients found to have severe stroke, identified as those with mRS 4-5 on discharge, as well as those with coronary heart disease, it was found that those patients given no antithrombotic therapy or given antiplatelet therapy alone were associated with an increased risk of death or admission for stroke, myocardial infraction, or major bleeding. An interesting observation from this study is that over 60% of patients with atrial fibrillation discharged after acute stroke are not managed according to current antithrombotic guideline recommendations. Finally, the authors recommended further clinical trials to determine the efficacy of antithrombotic therapy in patients with severe stroke and high cardiovascular risk.