Purpose: To determine if the addition of common carotid artery (CCA) intimal medial thickness (IMT) and internal carotid artery (ICA) stenosis could reclassify patients in the low and intermediate Framingham Risk Score (FRS) categories.
Method: Our cardiology database and reporting system was searched for patients with a low or an intermediate FRS, who have also had carotid duplex imaging performed. 154 patients had all the necessary data points entered: FRS, R) CCA IMT, L) CCA IMT and, if applicable, any ICA stenosis using Intersocietal commision for the accreditation of vascular laboratories (ICAVL) imaging and velocity criteria. A CCA IMT >0.99mm was considered abnormal as was the presence of any degree of ICA stenosis in either carotid territory.
Results: Of the 154 P, 58 were low FRS and 96 were intermediate FRS. 27 P patients (46.5%) in the low FRS group had an abnormal carotid study, and 71 patients (74.0%) in the intermediate FRS group had an abnormal carotid study. Of the 308 ICA in the 154 patients studied, 121 ICA (39.8%) had an ICA stenosis based on ICAVL imaging and velocity criteria. There were 103 ICA with a stenosis of 1-39%, 14 ICA with a stenosis of 40-59% and 4 ICA with a stenosis of 60-79%. A further 39 CCA had an IMT of >0.99mm as their only abnormality. Overall 52.6% of the 304 carotid territories had abnormalities. See Table 1.
Conclusions: 74% of all intermediate FRS P are reclassified as high risk, and the remaining 26% are reclassified as low risk when carotid duplex imaging data is added. 46.5% of all low FRS patients are reclassified as high risk when carotid duplex imaging data is added. This has important therapeutic ramifications with respect to the lipid target values and vascular protective therapy for both groups. We believe that all patients with an intermediate FRS should undergo carotid duplex imaging, and serious consideration should be given to low FRS patients, to ensure proper classification of vascular risk.