Revista Argentina de Radiología (Sep 2011)
Medición del espesor miointimal carotídeo como predictor de riesgo de accidente isquémico transitorio Carotid Intima - Media Thickness measurement as a risk predictor of transient ischemic attack Objectives
Abstract
Objetivos. Determinar si el riesgo de accidente isquémico transitorio (AIT) es mayor en pacientes con valores anormales de espesor miointimal carotídeo (EMIC). Materiales y Métodos. Evaluación de 168 pacientes con y sin AIT estudiados con ecografías de vasos de cuello, midiendo EMIC. Diseño de casos y controles apareados por distintas variables. Análisis estadístico: variables continuas (media ± DS), comparadas mediante prueba "t de Student" para muestras relacionadas. Variables categóricas (porcentajes) comparadas mediante pruebas de McNemar. Para evaluar EMIC como predictor de AIT, se ajustaron dos modelos de regresión logística condicional, considerando EMIC como variable continua y como variable binaria EMIC normal (1 mm). Se construyó una curva ROC para evaluar la capacidad discriminativa de EMIC, calculando la sensibilidad y especificidad para diferentes puntos de corte. Resultados. Valor de EMIC: casos 1,03 ± 0,31 mm (IC 95%: 0,97-1,10); controles 0,77 ± 0,27mm (IC 95%: 0,710,83); pTo determine if the risk of transient ischemic attack (TIA) is higher in patients with abnormal values of carotid intima-media thickness (CIMT). Materials and Methods. We evaluated 168 patients with and without TIA by ultrasound of the neck vessels, measuring CIMT. Case and controls were matched according to different variables. Statistical analysis: continuous variables (mean ± SD) were compared using the Student's t test for related samples. Categorical variables (percentages) were compared using the McNemar tests. In order to assess CIMT as a predictor of TIA, two models of conditional logistic regression were adjusted, considering CIMT both as a continuous variable and as a binary variable: normal CIMT (1 mm). A ROC curve was performed to determine the discriminative capacity of CIMT, estimating the sensitivity and specificity for different cutoff values. Results. CIMT value: cases 1.03±0.31 mm (95% CI: 0.971.10); controls 0.77±0.27 mm (95% CI: 0.71-0.83); p<0.001. The risk of TIA was about 9 fold higher in patients with abnormal CIMT (OR=8.8; p<0.001). With 95 % confidence interval we were able to affirm that for each 0.05 mm increase in CIMT, the risk of TIA increased between 16 and 44%. Area under ROC curve: 0.75 (95% CI: 0.67-0.82). Conclusions. Abnormal values of CIMT are significantly associated with a higher probability of suffering a TIA. According to our experience, the carotid wall US examination would allow to predict cerebrovascular preclinical disease.
