Increase in carotid IMT is considered marker of early atherosclerosis. However, experimental and clinical studies suggest that changes in arterial wall thickness may also represent an adaptive response to chronic changes in vessel diameter and/or intraluminal BP aimed to normalize wall tensile stress (WTS).

Aim of the study: to assess whether in healthy young-to middle-aged population a short-term common carotid (CCA) IMT progression rate (ΔIMT) is associated with WTS at baseline.

Methods: study population consisted of 749 healthy subjects at low-average Framingham risk (327 men, age=45±8 years) undergoing carotid US, fasting blood test (LDL-and HDL-cholesterol, triglycerides), oral glucose tolerance test and questionnaire regarding smoking and family history of cardiovascular diseases at baseline and after 3-year follow-up. WTS was calculated as (diastolic BP^*CCA radius)/IMT.

Results: during a 3-year period, BMI, waist girth, systolic and diastolic BP and plasma glucose increased (p<0.001), HR decreased (p<0.001), and plasma lipids and insulin did not change significantly. CCA diameter (+0.09±0.30 mm, p<0.0001) and IMT (+18±58 μm, p<0.0001) increased, whereas WTS (−0.27±6.70 kPa, p=0.36) remained unchanged. ΔIMT significantly increased by WTS quartiles at baseline (p<0.0001). In multiple regression model, adjusted for gender, smoking, family history and atherosclerotic risk factors (or their 3-year changes), the only independent determinants of ΔIMT were male gender, age and WTS at baseline (β±SE: 0.12±0.04, 0.17±0.04 and 0.32±0.04, cumulative R²=0.20, p<0.0001).

Conclusions: In healthy young-to-middle-aged population, the strongest predictor of short-term IMT progression rate was baseline WTS, followed by age and gender. Thus, IMT increase cannot be always considered marker of atherosclerosis.