Incremental predictive value of vascular assessments combined with the Framingham Risk Score for prediction of coronary events in subjects of low-intermediate risk

Background: In patients with low-intermediate risk, the use of the Framingham Risk Score (FRS) may not allow accurate prediction of the occurrence of coronary events. Objective: To determine whether non-invasive vascular sonographic assessments add value to the FRS for prediction of coronary events. Methods: Brachial artery flow-mediated dilatation (FMD), carotid intima-media thickness (IMT) and the presence of carotid plaque in 70 male subjects (mean (SD) age 62 (9) years) with a low-intermediate FRS who presented with a recent coronary event were evaluated and compared with those in 35 male controls matched for age (mean age 60 (9) years). Results: Patients with a recent coronary event had a significantly higher FRS than controls. They had a significantly lower FMD (3.56 (2.41)% vs 5.18 (2.69)%, p = 0.003) and significantly higher prevalence of carotid plaque (67% vs 40%, p = 0.008), but there was no significant difference in mean maximum IMT between the two groups (1.01 (0.28) vs 0.96 (0.14) mm, p = 0.32). Multivariate analysis revealed that FMD <= 4.75% was an independent predictor of an acute coronary event. Of the three vascular markers, FMD (4.75% and presence of carotid plaque provided the best diagnostic accuracy for a coronary event, with area under the curve (AUC) of 0.70 and 0.64 (p = 0.001 and p = 0.033), respectively, based on receiver operating characteristic curve analysis. Furthermore, incorporating carotid plaque or FMD (4.75% into the FRS (AUC = 0.72 and AUC = 0.78) provided incremental benefit in risk stratification over FRS alone (AUC = 0.66) (p = 0.008 and p = 0.007, for comparison of difference in two receiver operating characteristic curves). Conclusions: Incorporating a measure of FMD or carotid plaque burden with FRS significantly increases the accuracy of predicting coronary events in subjects of low intermediate risk and hence should be considered as additional investigations to improve coronary risk assessment.