Both carotid intima-media thickness (IMT) and arterial plaques have been shown to predict future CV events. Since there are no previous studies on the subject, our objective was to compare carotid IMT and the length of plaques in abdominal-pelvic main arteries in CV risk assessment in a prospective study setting with a follow-up of over 20 years.
A total of 1007 patients (50% men), aged 51 ± 6.0 years, participated in the current study. Carotid IMT and the summarized plaque length (SUM) from abdominal aorta to common femoral arteries were ultrasonographically assessed. Patients were followed-up a median (1st-3rd quartile) of 22.5 (17.5-23.2) years for CV events.
SUM significantly predicted CV events (HR per every 10 mm increase: 1.035, 95% CI: 1.027-1.044, p < 0.001). Those in the highest SUM tertile had over 3-fold risk for CV event (HR: 3.392, 95% CI: 2.427-4.741, p < 0.001) when compared to those in the lowest tertile. SUM significantly predicted CV events even after adjusting for age, sex, hypertension, diabetes, smoking (pack-years), LDL cholesterol and IMT. Adding SUM to the established model improved C-index (95% CI) from 0.706 (0.674-0.738) to 0.718 (0.688-0.747) as well as both discrimination (p < 0.001) and reclassification (p < 0.001) of the patients. In contrast, IMT predicted cardiovascular events only in univariate analysis and it did not improve discrimination or reclassification of the patients.
In light of our findings, SUM is a superior indicator and clinical tool for evaluating the overall CV risk compared to carotid IMT.

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