P6.17 CARDIOVASCULAR RISK FACTORS CONTRIBUTE TO THE VARIANCE OF WALL-TO-LUMEN RATIO

Abstract

Background: Common carotid artery intima-media thickness (cIMT) is an accepted ultrasound marker of subclinical atherosclerosis. It is argued that increase in cIMT may also reflect nonatherosclerotic thickening, thus, lumen diameter could be taken into account. A common approach to account for lumen diameter is wall-to-lumen ratio (WLR), however, its precise relations to cardiovasular risk factors remain unclear. We attempted to compare the contribution of cardiovascular risk factors to the variance in cIMT and WLR. Methods: Noninvasive measurements of cIMT and WLR were made with high-resolution ultrasonography in 5,983 subjects. They were male aged 40 to 55 and female aged 50 to 65 without previous cardiovascular events, participating in the Lithuanian High Cardiovascular Risk primary prevention program. We performed a multiple linear regression on cIMT and WLR incorporating traditional and less traditional cardiovascular risk factors. Results: Mean left and right cIMT was 0.66 ± 0.12 mm and 0.65 ± 0.11 mm respectively, whereas mean WLR was 0.092 ± 0.015. We found that cardiovascular risk factors could explain 8.9% of left cIMT and 8.3% of right cIMT. Strikingly, traditional and less traditional factors (namely age, male sex, LDL/HDL ratio, mean arterial blood pressure and triglyceride) contributed to a significantly larger proportion of WLR variance, amounting to 14.2%. Conclusions: Adjustment for carotid lumen diameter in analyses evaluating common carotid artery intima-media thickness should be considered. The precise role of WLR as an ultrasound marker of subclinical atherosclerosis remains a topic of interest for future research.