Symptomatic Carotid Occlusion Is Frequently Associated With Microembolization.

BACKGROUND AND PURPOSE: Symptomatic carotid artery disease is associated with significant morbidity and mortality. The pathophysiologic mechanisms of cerebral ischemia among patients with carotid occlusion remain underexplored. METHODS: We conducted a prospective observational cohort study of patients hospitalized within 7 days of ischemic stroke or transient ischemic attack because of ≥50% carotid artery stenosis or occlusion. Transcranial Doppler emboli detection was performed in the middle cerebral artery ipsilateral to the symptomatic carotid. We describe the prevalence of microembolic signals (MES), characterize infarct topography, and report clinical outcomes at 90 days. RESULTS: Forty-seven patients, 19 with carotid occlusion and 28 with carotid stenosis, had complete transcranial Doppler recordings and were included in the final analysis. MES were present in 38%. There was no difference in MES between those with carotid occlusion (7/19, 37%) compared with stenosis (11/28, 39%; P=0.87). In patients with radiographic evidence of infarction (n=39), 38% had a watershed pattern of infarction, 41% had a nonwatershed pattern, and 21% had a combination. MES were present in 40% of patients with a watershed pattern of infarction. Recurrent cerebral ischemia occurred in 9 patients (19%; 6 with transient ischemic attack, 3 with ischemic stroke). There was no difference in the rate of recurrence in those with compared to those without MES. CONCLUSIONS: Cerebral embolization plays an important role in the pathophysiology of ischemia in both carotid occlusion and stenosis, even among patients with watershed infarcts. The role of aggressive antithrombotic and antiplatelet therapy for symptomatic carotid occlusions may warrant further investigation given our findings.

Convergent validity and interrater reliability of estimating the ABCD2 score from medical records.

BACKGROUND AND PURPOSE: The ABCD(2) score is increasingly used for risk stratification of transient ischemic attack patients. We sought to determine the reliability and convergent validity of retrospective ABCD(2) score estimation from medical records. METHODS: We compared ABCD(2) scores that were prospectively determined by a vascular neurology attending to scores determined retrospectively from medical record review. Emergency department records and neurology consult notes for patients with acute transient ischemic attack were abstracted with explicit ABCD(2) scoring redacted. Scores were estimated by 2 independent raters using these records. Estimated ABCD(2) component scores, total scores, and risk category were compared both between retrospective raters and with prospectively obtained scores. Reliability was assessed using unweighted κ statistics. RESULTS: Interrater reliability was substantial with 72% exact agreement in total score between retrospective raters (κ=0.64) and nearly perfect with 82% agreement for ABCD(2) category (κ=0.71). Interrater agreement was best for age and diabetes mellitus and poorest for clinical features and duration. Agreement between the retrospective raters and prospectively obtained score was >90% for age, blood pressure, and diabetes mellitus, but only ≈70% for clinical features and duration. Retrospectively, estimated total ABCD(2) score exactly matched the prospective score in 58% of patients for rater 1 and 44% of patients for rater 2. Retrospectively, estimated ABCD(2) category matched the prospectively scored category in 67% of patients for rater 1 and 71% of patients for rater 2. CONCLUSIONS: The ABCD(2) score can be abstracted from medical records with substantial interrater reliability but limited convergent validity. This may lead to misclassification of risk category in more than one third of patients.