A prediction model for unstable carotid atheromatous plaque in acute ischemic stroke patients: proposal and internal validation.

The aim of this prospective study was to analyze the utility of a gray-scale median (GSM) system for identifying unstable plaques and to design and validate a prediction model for unstable plaques in symptomatic atheromatous carotid arteries. Fifty-two patients with non-cardioembolic cerebral infarction were included in the study. The receiver operating characteristic analysis revealed 76% sensitivity and 82% specificity for a GSM of 29 (p < 0.001) as a cutoff point for unstable plaques. A logistic regression model indicated that a GSM <29, male gender and not having been treated with angiotensin-converting enzyme inhibitors were independently associated with an unstable plaque classification. A probability model for unstable plaques was achieved by combining the strength of each variable (high blood pressure, hypercholesterolemia, smoking, previous stroke, anti-hypertensive drugs, calcium channel blockers, intima-media thickness). The model was tested with receiver operating characteristic curve analysis (p < 0.001) and validated by the leave-one-out cross-validation method (p < 0.001). The prediction model based on a GSM <29, male gender and not having been treated with angiotensin-converting enzyme inhibitors resulted in a probable unstable plaque assessment.