Noninvasive assessment of endothelial dysfunction by brachial artery flow-mediated dilatation in prediction of coronary artery disease in Indian subjects.

ABSTRACT

BACKGROUND: A noninvasive technique for testing endothelial function by ultrasound measurement of flow-mediated dilatation has recently generated considerable interest as a marker of atherosclerosis, and in the prediction of clinical coronary events and coronary artery disease. METHODS AND RESULTS: We measured the flow-mediated dilatation of the brachial artery (endothelium-dependent vasodilatation) in 136 subjects, with or without evidence of coronary artery disease. Endothelial dysfunction was diagnosed if flow-mediated dilatation was less than 4.5%. Of the 136 subjects (age group 40-70 years) recruited for the study, 94 were males and 42 females. Sixty-eight subjects had evidence of coronary artery disease as diagnosed by documented hospitalization due to myocardial infarction or acute coronary syndrome, proved by coronary angiography when feasible or noninvasive cardiac evaluation. Endothelial dysfunction was detected in 90 subjects (66.2%). Prevalence of coronary artery disease was higher among subjects with endothelial dysfunction compared to those without (57.5% v. 34.7%, p=0.013). Prevalence of endothelial dysfunction was significantly higher among subjects with coronary artery disease as compared to those without coronary artery disease (76.4% v. 55.8%, p=0.012). The present study showed a sensitivity of 76%, specificity of 44%, positive predictive value of 58% and negative predictive value of 65% for endothelial dysfunction in the prediction of coronary artery disease. Multiple regression analysis using coronary artery disease as a dependent variable revealed a statistically significant association with endothelial dysfunction (p=0.033) even after the inclusion of traditional risk factors into the model. CONCLUSIONS: We conclude that endothelial dysfunction shows a strong association with coronary artery disease and can be a useful noninvasive tool for the evaluation of coronary artery disease.