Silent infarcts prognostic in young stroke patients

Sep 12 2012

By Eleanor McDermid, Senior medwireNews Reporter

Silent ischemic lesions are common and are associated with a high rate of recurrent events in young patients with acute ischemic stroke, report researchers.

"In such patients, careful follow-up and extensive investigations to identify underlying traditional and nontraditional vascular risk factors are therefore warranted," say Alexandre Poppe (University of Montreal, Quebec, Canada) and colleagues.

Using magnetic resonance imaging, the team identified silent ischemic lesions in 28.2% of 170 patients aged 50 years or younger. A previous Finnish study found lesions in 18% of a cohort of patients younger than 50 years; the Finnish study was population-based, whereas Poppe and team studied hospitalized patients. Both studies found silent ischemic lesions to be predictive of recurrent events.

"Our similar findings therefore support generalizability of the association between [silent ischemic lesions] and recurrent ischemic stroke in young patients with arterial ischemic stroke," write Poppe et al in Neurology.

They report that 23.0% of patients with silent ischemic lesions had a recurrent stroke during an average 25 months of follow up, compared with just 6.5% of those without. After accounting for confounders, the presence of silent ischemic lesions raised patients' risk for recurrent stroke 3.2-fold, and their risk was raised even more if they also had leukoaraiosis, at a 7.3-fold increase.

No patient had leukoaraiosis without silent ischemic lesions, leading the researchers to suggest that leukoaraiosis may represent accumulations of silent lesions.

Silent ischemic lesions were associated with increased rates of hypertension and coronary artery disease, and also with migraine with aura, but not migraine without aura. Migraine with aura has been linked to stroke risk in young patients, but not in older patients, in whom the effects of conditions such as hypertension and diabetes may outweigh the influence of migraine. There was also a high rate of Type 2 diabetes among patients who had both silent ischemic lesions and leukoaraiosis.

Poppe et al believe that the presence of silent ischemic lesions "may represent the cumulative effect of exposure to various vascular risk factors and hence remains an independent predictor of stroke recurrence even after adjustment for baseline risk factors."

The absence of such lesions in some young patients therefore "probably reflects stroke mechanisms that are monophasic and carry a lower recurrence risk."

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