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In studies of CAS, stroke rates depend on stroke definition
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A standard definition of what constitutes a major stroke or minor stroke should be enacted for trials comparing carotid artery stenting and carotid endarterectomy, according to an analysis published in EuroIntervention.
Researchers found widely different rates of stroke in such studies because there was no uniform definition used.
Stephan Staubach, MD , from the department of cardiology, pneumology and intensive care, Municipal Hospital Munich GmbH, Neuperlach Clinic in Munich, and colleagues analyzed data from 947 percutaneous carotid interventions in symptomatic and asymptomatic patients with relevant carotid artery stenting (CAS) from 1999 to 2014.
They calculated stroke rates from that cohort based on the definitions used in various CAS registries and randomized trials comparing CAS with endarterectomy.
“An updated definition of stroke ... includes objective evidence of ischemic injury by imaging and clinical evidence based on symptoms persisting 24 hours until death,” the researchers wrote. “In several large registries and randomized trials comparing carotid endarterectomy and CAS, stroke is categorized as minor or major stroke.”
Each patient from the cohort was examined twice by a board-certified neurologist before and after the intervention, and again if a neurological deficit occurred.
Each deficit was given a score based on the NIH Stroke Scale and the modified Rankin scale, whereas Fleiss’ kappa and Cohen’s kappa test were employed to differentiate between major and minor strokes.
The researchers found that, during 30 days, 3.6% of the cohort experienced stroke. By study-determined definition (major stroke = symptoms lasting > 30 days, NIHS Stroke Scale 4 and/or modified Rankin scale 3), 1.6% of the patients sustained a major stroke while 2% experienced a minor one. All determinations of stroke were in substantial agreement (Fleiss’ kappa = 0.73.)
By the researchers’ definition, 19 patients experienced minor strokes and 15 experienced major ones, but across other definitions used, minor strokes ranged from 14 patients to 22 patients and major strokes ranged from 13 patients to 20 patients, Staubach and colleagues wrote.
“There is no general agreement on the timing of the assessment of stroke severity,” they wrote. “This is important because some patients improve ... due to early therapy or intensive rehabilitation; however, a smaller proportion shows clinical impairment. Hence, minor stroke may be different depending on the moment of clinical examination of the patients.” – by James Clark
Disclosure: The researchers report no relevant financial disclosures.
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