Variation of segment specific carotid artery intima-media thickness in a selected Sri Lankan population.

Abstract

Introduction and objective Carotid artery intima-media thickness (CIMT) is a strong predictor of coronary heart disease (CHD). The literature debates considering segment-specific CIMT variation while constructing country-specific risk prediction models to screen at-risk populations. We evaluated segment-and site-specific variation in CIMT to derive a composite score for Sri Lankans. Methods The study was conducted from November 2019 to October 2020 in a private hospital in Colombo. Based on predefined inclusion-exclusion criteria, cases (having a CHD diagnosis, n=338) and controls (n=356) were recruited. People without any suggestive medical history of having angina type chest pain , no significant ECG changes suggestive of acute coronary syndrome, negative treadmill test, normal echocardiographic evidence and negative test results of Troponin I and T were considered as controls. Ultrasound examination of the common-carotid-(CCA), the carotid-bulb-(CB) and the internalcarotid segments-(ICA) of the carotid vessel were conducted by a radiologist, and CIMTs were measured. A composite-CIMT score defined as the average value of all six segments of both the left and right sides was derived. Results 694 participants were enrolled. The mean-(+SD) age of the study sample was 60.2(±9.86) years. The highest mean-(+SD) CIMT value was in the CB-(0.89 (±0.09mm)) in the CHD group and in the CCA-(0.72 (±0.11mm)) in the non-CHD group. The lowest mean-(+SD) CIMT was in the ICA in both the CHD group-(0.86 (±0.08mm)) and in the non-CHD-(0.69 (±0.11mm)). There was a significant difference in the mean CIMT values between the right and left sides (p<0.05 for all) in both the two groups. The composite value for CHD and non-CHD groups was 0.88(±0.07) mm and 0.71(±0.09) mm (P<0.001). Conclusion Carotid artery segment-specific-CIMT variations are present in this population. Further analyses should be carried out to determine if a composite-CIMT value is a better predictor of CHD.