Published online before print May 17, 2007, doi: 10.1161/STROKEAHA.107.484030
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(Stroke. 2007;38:e61.)
© 2007 American Heart Association, Inc.
Letters to the Editor |
Impact of Anticoagulation on Poststroke Mortality in Ischemic Stroke Patients With Atrial Fibrillation
Neurosonology and Stroke Research Program, Barrow Neurological Institute, Phoenix, Ariz, Department of Neurology, University of Athens School of Medicine, Athens, Greece
Department of Neurology, University of Athens School of Medicine, Athens, Greece
To the Editor:
We read with great interest the recent study by Andersen and Olsen regarding the usefulness of anticoagulation treatment in reducing poststroke mortality in patients with ischemic stroke (IS) and atrial fibrillation (AF). The authors, after evaluating data from a prospective nationwide registry, concluded that IS patients with AF and no contraindication to oral anticoagulants (OA) had an almost 50% reduction in the hazard of death when secondary prevention with anticoagulation treatment was instituted. This effect was independent of age, stroke severity, and stroke risk factors.1 The former findings raise certain potential clinical implications regarding the optimal management of IS survivors with AF, because in a previous randomized controlled trial no significant benefit of oral anticoagulation on poststroke mortality was identified.2
Our group has previously investigated the efficacy and safety of OA for secondary prevention in specific subgroups of IS patients with AF (age older than 75 years, moderate-to-severe stroke severity) that have been under-represented or excluded from randomized controlled trials. Interestingly, we documented similar results to the findings of Andersen and Olsen. More specifically, OA decreased the risk of recurrent thromboembolism (stroke and systemic embolism) by approximately two-thirds (HR=0.31 for patients older than 75 years; HR=0.36 for patients with moderate-to-severe stroke) and halved the risk of poststroke mortality (HR=0.47 for patients older than 75 years; HR=0.44 for patients with moderate-to-severe stroke) after adjustment for demographic characteristics and cardiovascular risk factors.3,4
In people older than 75 years, AF is the most important single cause of IS,5 whereas AF patients with disabling stroke carry a high intrinsic risk of recurrent thromboembolism.6,7 In view of the limited randomized data regarding the effect of OA on long-term prognosis of patients with moderate-to-severe IS and aged older than 75 years, which has led to a significant underuse of anticoagulation therapy in these 2 stroke subgroups,8 Andersen and Olsen may consider comparing the benefit of OA between patients of 75 or younger and those older than 75 years old, as well as between patients with mild and moderate-to-severe stroke. Should a higher preventive effect of anticoagulation be identified in patients of older age and more severe strokes, then this finding may constitute an important argument in favor of the wider implementation of OA in these 2 undertreated IS subgroups. Additionally, it would be interesting to evaluate the influence of AF profile (chronic versus intermittent) on poststroke mortality in this large nationwide stroke registry, because recent studies have indicated that intermittency of rhythm does not appear to affect stroke risk when other risk factors are considered.3,4,9
In the absence of definitive evidence from randomized controlled trials, the data from this large prospective Danish cohort, although obtained in a nonrandomized and uncontrolled setting, provide useful information regarding the potential beneficial impact of oral anticoagulation on the risk of poststroke mortality and strengthen the case of wider but judicious use of OA in IS survivors with no contraindication to antithrombotic therapy, regardless of their age or stroke severity.
Acknowledgments
Disclosures
None.
References
1. Andersen KK, Olsen TS. Reduced poststroke mortality in patients with stroke and atrial fibrillation treated with anticoagulants. Results from a Danish quality-control registry of 22,179 patients with ischemic stroke. Stroke. 2007; 38: 259–263.
2. EAFT (European Atrial Fibrillation Trial) Study Group. Secondary prevention in non-rheumatic atrial fibrillation after transient ischaemic attack or minor stroke. Lancet. 1993; 342: 1255–1262.[Medline] [Order article via Infotrieve]
3. Vemmos KN, Tsivgoulis T, Spengos K, Manios E, Toumanidis S, Zakopoulos N, Moulopoulos SD. Anticoagulation influences long-term outcome in patients with non-valvular atrial fibrillation and severe ischemic stroke. Am J Geriatr Pharmacother. 2004; 2: 265–273.[CrossRef][Medline] [Order article via Infotrieve]
4. Tsivgoulis G, Spengos K, Zakopoulos N, Manios E, Peppes V, Vemmos K Efficacy of anticoagulation for secondary stroke prevention in older people with non-valvular atrial fibrillation: a prospective case series study. Age Ageing. 2005; 34: 35–40.
5. Hart RG, Halperin JL. Atrial fibrillation and stroke: concepts and controversies. Stroke. 2001; 32: 803–808.
6. Hart RG, Halperin JL. Atrial fibrillation and thromboembolism: a decade of progress in stroke prevention. Ann Intern Med. 1999; 131: 688–695.
7. Hart RG, Pearce LA, Miller VT, Anderson DC, Rothrock JF, Albers GW, Nasco E. Cardioembolic vs. noncardioembolic strokes in atrial fibrillation: frequency and effect of antithrombotic agents in the stroke prevention in atrial fibrillation studies. Cerebrovasc Dis. 2000; 10: 39–43.[CrossRef][Medline] [Order article via Infotrieve]
8. Devereaux PJ, Anderson DR, Gardner MJ, Putnam W, Flowerdew GJ, Brownell BF, Nagpal S, Cox JL. Differences between perspectives of physicians and patients on anticoagulation in patients on anticoagulation in patients with atrial fibrillation: observational study. BMJ. 2001; 323: 1–7.
9. Hart RG, Pearce LA, Rothbart RM, McAnulty JH, Asinger RW, Halperin JL. Stroke with intermittent atrial fibrillation: incidence and predictors during aspirin therapy. Stroke Prevention in Atrial Fibrillation Investigators. J Am Coll Cardiol. 2000; 35: 183–187.
Related Article:
Stroke 2007 38: e62.
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