Etiologic work-up crucial after stroke

By Eleanor McDermid, Senior medwireNews Reporter

An elusive stroke etiology does not diminish the importance of a full work-up, say researchers.

In their study, the mortality rate during the 3 years after stroke was highest in patients with undetermined etiology because of an incomplete work-up. At 35.7%, this was higher even than in patients with confirmed cardioembolic stroke (30.1%).

By contrast, patients with undetermined etiology despite a complete work-up had relatively low mortality rates, at about 12%. The lowest rates, of about 5%, were seen among patients with lacunar stroke.

The study involved 3278 Korean patients, 37% of whom had stroke of undetermined subtype according to the TOAST (Trial of ORG 10172 in Acute Stroke Treatment) classification.

Patients with incomplete work-ups (4.8% of all patients) had more severe stroke than other patients. Ji Hoe Heo (Yonsei University College of Medicine, Seoul, Korea) and team say that the presence of severe neurological deficits may explain why some patients were incompletely evaluated.

However, after accounting for admission stroke severity and other confounders, the risk for mortality remained high in patients with undetermined etiology because of an incomplete work-up, at a 2.53-fold increase relative to patients with lacunar stroke.

The highest risk increase, of 2.84-fold, was in patients with cardioembolic stroke, whereas the smallest increase, of 1.67-fold, was in patients with stroke of undetermined etiology despite a complete etiologic work-up.

No patient with an incomplete evaluation underwent an angiographic evaluation, compared with 87-100% of other patients. "Therefore, the presence of significant carotid stenosis that might require stent/carotid endarterectomy could be missed," the researchers write in Stroke. "Lack of those evaluations and treatments in some patients with an incomplete evaluation could result in an increased risk of stroke recurrence and death."

Indeed, the high mortality rate in patients with incomplete work-ups appeared partly due to a high rate of fatal stroke, which occurred in about 25% of these patients over the 3-year period. Again, the rate was low in patients with undetermined etiology despite a complete work-up, at less than 5%.

The team concludes: "Taken together, our findings suggest the importance of initial evaluation for defining the stroke subtype and determining the prognosis."

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