Evaluation of Carotid Intima Media thickness as a predictor of Macrovascular complications in Type 2 Diabetes Mellitus

The identification of arterial wall changes in asymptomatic subjects indicates the need for more strict control of macrovascular risk factors, seeking to prevent future macrovascular events. Population and hospital based studies using non-invasive techniques to evaluate early changes in the structure and function of the arterial wall, such as the measurement of intima media wall thickness, investigation of endothelial dysfunction and macrovascular calcification (63, 64, and 65) have been employed for the purpose. Studies determined 0.8 mm as the reference values for early thickening of the intima media complex associated with an increase in macrovascular risk (54, 66-69). Grook et al conducted a study with 315 patients with familial hypercholesterolemia compared 118 controls and showed that an intima media thickening of up to 0.8 mm would be considered normal. The present study shows that even asymptomatic patients with T2DM has increased carotid IMT value and the risk of acquiring macro vascular combination increase as IMT value increases. This study shows that increasing CIMT is strongly associated with macrovascular disease. In the present study we used mean aggregate IMT of the extra cranial arteries (altogether 6 sites at each common carotid artery, the bifurcation and the internal carotid artery) including thickness of plaque lesion, with a view to evaluate the association between macrovascular status and grade of carotid atherosclerosis. Mean IMT aggregate has been accessed in many previous studies, although in same of them it proved difficult to evaluate internal carotid intima media thickness precisely (50, 59). However, technological advancement in ultrasound equipment and the availability of high resolution transducer has allowed more accurate evaluation of arterial wall structure in past decade. The present study showed carotid artery IMT was higher in patients with macrovascular complication in T2DM than in patients without macrovascular complications in T2DM. Thickening of the mean aggregate intima media complex just over 1 mm may prove to the predictive of significant macrovascular disease in nearly 95% of the patients. The study observations are consistent with several previous studies Crouse et al (58) found a strong correlation between macrovascular disease and increased IMT in carotid artery diseases. Likewise, in my study mean aggregate IMT increases with advancing macrovascular disease. Other investigators carried out population based studies in which IMT was evaluated with regard to the number and incidence of stroke or acute coronary syndromes (60). A strong association between IMT and risk of stroke and myocardial infection was established in Rotterdam study (60). Bots et al (53) used B mode ultrasonography to study the carotid arteries of 7983 patients aged over 55 years. Throughout 4.6 years of observation they registered 194 new myocardial infections in the study going patients who has myocardial infarction had significantly higher IMT than others. Furthermore, O’ leary et al (55) having examined over 5800 patients (>65 years) with high resolution ultrasonography found increased IMT of carotid arteries directly associated with increased risk of myocardial infarction and stroke. Since, both the sensitivity and specificity of Treadmill testing and Echocardiography are limited; the introduction of IMT measurements of the carotid arteries may contribute significantly to diagnose the status of patients. In these patients high aggregated IMT in carotid arteries may be adhesive factor in introduction of effective medical treatment such as statins and antihypertensive drugs along with effective blood sugar control. IMT may be considered as another risk factor for CAD, in the same way of Diabetes, hypertension according to recommendations of European society of cardiology publications 2000. The non-invasive assessment of common carotid intima media thickness appears to provide a promising method of study of atherosclerosis directly at the level of vessel in population at large. The use of carotid intima media thickness measurements as an indicator of generalized atherosclerosis is conditioned on the view that its measurement reflects on macrovascular disease risk. CONCLUSION : In conclusion, the present studies based on short follow up periods: 1. Even in asymptomatic type 2 diabetic patients have increased carotid intima media thickness. 2. An increase in carotid intima media thickness strongly goes in hand with macrovascular complications. 3. Intima media thickness measurement has an intermediate or proxy end point in observational and interventional study