The utility of ultrasonic tissue characterization of carotid plaque in the prediction of cardiovascular events in diabetic patients

•Cardiovascular disease (CVD) is the main cause of death in diabetic patients.•We examine the association between the carotid plaque echogenicity and the CVD risk.•The risk of CVD is higher in diabetic subjects with echolucent carotid plaques.•The presence of echolucent carotid plaques is an independent risk factor for CVD.•The evaluation of carotid plaque echogenicity improves the risk prediction of CVD.

ObjectiveThe aim of this study was to evaluate whether non-invasive ultrasonic tissue characterization of carotid plaque using gray-scale median (GSM) can be a predictor of future cardiovascular disease (CVD) events in type 2 diabetic patients.MethodsA total of 287 type 2 diabetic patients with carotid plaque but without CVD were enrolled (male 72%, mean age 65 ± 7 years). We prospectively evaluated the association between GSM, a quantitative parameter of the plaque echogenicity, and CVD.ResultsThe median follow-up period was 55 months, and there were 34 new CVD events. The risk of CVD event was significantly higher in the patients with echolucent (GSM ≤ 37) plaque (n = 67) as compared to those without (n = 220) (HR = 6.99, 95% CI 3.46-14.14, p < 0.001). Cox proportional hazards regression analysis showed that the presence of echolucent plaque (HR = 4.55, 95% CI 2.10-19.84, p < 0.001) as well as plaque thickness (HR = 1.44, 95% CI 1.01-2.06, p = 0.005) were independent predictors of CVD, even after adjustment for other risk factors. Time-dependent receiver-operating-characteristic curve analysis revealed that the addition of plaque thickness to Framingham risk score (FRS) resulted in significant increase in area under the curve (AUC) [from 0.60 (95% CI; 0.49-0.70) to 0.73 (95% CI; 0.63-0.82), p < 0.05]. Notably, the addition of plaque echogenicity (presence/absence of echolucent plaque) to the FRS and plaque thickness resulted in further and significant increase in AUC [from 0.73 (95% CI; 0.63-0.82) to 0.82 (95% CI; 0.75-0.88), p < 0.05].ConclusionUltrasonic tissue characterization of carotid plaque using the GSM can improve the risk prediction of cardiovascular event in asymptomatic type 2 diabetic patients with carotid plaque.