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Prognosis After Transient Monocular Blindness

Among patients who present with transient ischemic attacks (TIAs), do prognoses differ between those with transient monocular blindness (amaurosis fugax) and those with hemispheric symptoms? To address this question, researchers analyzed data from a previously published North American trial in which medical therapy and carotid endarterectomy were compared in 2885 patients with nondisabling stroke or TIA (see JW Dec 1 1998, p. 181, accession number 981113001, and N Engl J Med 1998; 339:1415).

The trial included 397 patients whose only previous cerebrovascular event was transient monocular blindness and 928 whose only event was hemispheric TIA. During 3 years of follow-up, medically treated patients with transient monocular blindness and 50 percent or greater carotid stenosis had a 10 percent risk for ipsilateral stroke -- exactly half that of patients with hemispheric TIA. Among patients with transient monocular blindness and 50 percent or greater carotid stenosis, 6 risk factors (including male sex and age 75 or older) predicted subsequent ipsilateral stroke. Patients with at least 3 risk factors had a 3-year stroke risk of 24 percent with medical therapy and of 10 percent with surgery; those with 2 risk factors had risks of 12 percent and 7 percent, respectively, and those with 0 or 1 risk factor had risks of 2 percent and 4 percent, respectively.

Comment: This analysis confirms that an episode of transient monocular blindness confers lower risk for subsequent stroke than does hemispheric TIA. In addition, the findings suggest that carotid endarterectomy is beneficial only for a high-risk subset of patients with transient monocular blindness. This issue of The New England Journal of Medicine also includes a review of treatment approaches for patients with carotid stenosis.

— AS Brett

Published in Journal Watch General Medicine October 19, 2001

Citation(s):

Benavente O et al. Prognosis after transient monocular blindness associated with carotid-artery stenosis. N Engl J Med 2001 Oct 11 345 1084-1090.

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Sacco RL. Extracranial carotid stenosis. N Engl J Med 2001 Oct 11 345 1113-1118.

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• Medline abstract (Free)