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

Abstract

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.