The Carotid Intima Media Thickness: A Predictor of the Clincal Coronary Events

Background: The Carotid Intima-Media Thickness (CIMT) is a simple and an inexpensive tool which can be used to assess the cumulative effect of atherosclerotic risk factors and it is also an independent predictor of the future cardiovascular risk. Nevertheless, criticism has been raised throughout the scientific community, based on the observations which indicated a weak correlation between CIMT and coronary atherosclerosis. It has been suggested by the International Atherosclerosis Project, that the atherosclerotic process occurs at the same time in the carotid, cerebral and the coronary arteries. Measurement of the Carotid Intima-Media Thickness (CIMT) of the Common Carotid Artery (CCA) by B-mode ultrasound was found to be a suitable non-invasive method, to visualize the arterial walls and to monitor the early stages of the atherosclerotic process. Aim: This study sought to determine the usefulness of B-mode ultrasound as a non-invasive marker to examine the association between CIMT and the extent and the severity of coronary artery disease and its association with the cardiovascular risk factors, if any. Methods: A cross-sectional study was done among hundred cases and hundred age and sex matched controls who were in the age group of 30-65 years. The cases included those who had undergone coronary angiography. The controls included non-diabetic non-hypertensives with no cardiovascular risk factors. The CIMT was assessed by using a 7MHz linear array transducer. Fasting blood samples were collected for measuring the blood sugar and the lipid profiles. Results: The statistical analysis was done by using the Student's t test and ANOVA and a p value of <0.001 was considered to be significant. The Average Carotid Intima Media Thickness (AVCIMT) was higher in the cases (0.90 vs 0.47 in controls, p<0.001, very highly significant). The AVCIMT was found to be higher in those with triple vessel disease (1.00mm) >double vessel disease (0.91mm) >single vessel disease (0.82mm) >normal coronaries (0.65mm). Conclusion: The easy applicability and the non invasive nature of B-mode ultrasonography make it suitable for use as a surrogate endpoint for measuring the atherosclerotic burden in people with cardiovascular risk factors. Even in this present study, we found a significant association between the extent of carotid atherosclerosis which was measured by B-mode ultrasound, and the presence, its extent, or the lack of coronary atherosclerosis which was documented by coronary angiography.