Correspondence

“Silent” Strokes and Dementia

N Engl J Med 2003; 349:96July 3, 2003

Article

To the Editor:

Vermeer et al. (March 27 issue)1 demonstrate associations between “silent” (asymptomatic) stroke and recurrent stroke and dementia. The risk of large strokes was the highest, with nonsignificant trends toward an increased risk of small-vessel or white-matter lesions. Whether incident silent infarcts and incident symptomatic infarcts confer similar risks of recurrent symptomatic stroke and dementia is unclear. If an analogy to carotid disease holds, there may be different risks for silent strokes and for symptomatic strokes.

Although the accompanying editorial by Blass and Ratan2 raises important issues about risk-factor modification in patients with a silent stroke, information is limited on combination antiplatelet therapy for the reduction of the risk of dementia. There are data showing decreases in overall mortality among patients with vascular dementia who are treated with any antithrombotic agent.3 However, there is no absolute benefit of antiplatelet drugs (including aspirin) in the prevention of a first symptomatic stroke.4 Sustained-release dipyridamole and aspirin are quite reasonable treatments for patients with symptomatic stroke, but clinical trials are needed in order to show whether specific antiplatelet drugs are cost effective in decreasing the risk of dementia after a silent infarction.5 Pending future investigations, aspirin alone might still be the initial choice for patients who are at high risk for cerebrovascular disease.4,5

Michael J. Schneck, M.D.
Loyola University Medical Center, Maywood, IL 60153
mschneck@lumc.edu

5 References

1. 1

   Vermeer SE, Prins ND, den Heijer T, Hofman A, Koudstaal PJ, Breteler MMB. Silent brain infarcts and the risk of dementia and cognitive decline. N Engl J Med 2003;348:1215-1222
   Full Text | Web of Science | Medline

2. 2

   Blass JP, Ratan RR. “Silent“ strokes and dementia. N Engl J Med 2003;348:1277-1278
   Full Text | Web of Science | Medline

3. 3

   Freels S, Nyenhuis DL, Gorelick PB. Predictors of survival in African American patients with AD, VaD, or stroke without dementia. Neurology 2002;59:1146-1153
   Web of Science | Medline

4. 4

   Hart RG, Halperin JL, McBride R, Benavente O, Man-Son-Hing M, Kronmal RA. Aspirin for the primary prevention of stroke and other major vascular events: meta-analysis and hypotheses. Arch Neurol 2000;3:326-332
   CrossRef | Web of Science

5. 5

   Antithrombotic Trialists' Collaboration. Collaborative meta-analysis of randomized trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients. BMJ 2002;342:71-86[Erratum, BMJ 2002;324:141.]
   

Author/Editor Response

Dr. Schneck's point about the need for further studies of silent stroke is well taken. We tried to make the same point in our editorial. Further studies will, we hope, provide clear information on whether clinically silent stroke should be treated more as a previous stroke or more as a marker of cardiovascular disease.

John P. Blass, M.D., Ph.D.
Raj R. Ratan, M.D., Ph.D.
Weill Medical College of Cornell University, White Plains, NY 10605