Using aortic distensibility index to detect coronary stenosis

OBJECTIVE: The aortic distensibility index, as a measure of vascular function, can serve as a marker of coronary artery disease severity. This study explores the feasibility of using the non-invasively measured index as an indicator of severity of coronary stenosis. METHODS: One hundred patients with normal left ventricular systolic function were prospectively enrolled. They were subjected to assessment of aortic distensibility using computed tomographic angiography and transthoracic echocardiography. Coronary artery disease severity and coronary artery calcium score were assessed. RESULTS: The mean age of the whole study cohort was 58 +/- 9 years, 63 (63%) being males. A significant inverse correlation was found between aortic distensibility measured using computed tomographic angiography and patients' age, systolic blood pressure, coronary artery calcium score and severity of coronary artery disease (percent luminal stenosis). However, there was no statistical correlation with the number of diseased coronary arteries. A strong direct correlation was recorded upon comparing aortic distensibility index values obtained using computed tomographic angiography and transthoracic echocardiography (r=0.325, P=0.004). Receiver operating characteristic curve analysis revealed that an echocardiography-derived aortic distensibility index value of 6.65% is associated with significant (50% luminal stenosis) coronary artery disease with a sensitivity of 83%, specificity of 93%, positive predictive value of 97% and negative predictive value of 65%. CONCLUSION: Non-invasive assessment of aortic distensibility indices is a feasible procedure to predict significant atherosclerotic coronary artery disease. Lower values are associated with significant obstructive coronary artery disease and high coronary artery calcium score.