Distensibility of the ascending aorta: comparison of invasive and non-invasive techniques in healthy men and in men with coronary artery disease.

Distensibility of the ascending aorta, measured non-invasively, was compared with values obtained by invasive techniques in 46 males (30 patients with coronary artery disease and 16 age-matched normal subjects). Aortic diameters were measured at a level 3 cm above the aortic valve using both echocardiographic and angiographic techniques. Aortic distensibility was calculated from the aortic diameters and aortic pressure or brachial artery pressure using the formula: 2 x (change in aortic diameter)/(diastolic aortic diameter) x (change in aortic pressure). Distensibility of the ascending aorta determined non-invasively was closely related to that obtained by direct measurements (r = 0.949, P less than 0.001). Patients with coronary artery disease had similar pressures, but markedly lower distensibility than normal subjects, as shown by both invasive and non-invasive techniques. The results indicate that aortic distensibility in patients with coronary artery disease can be obtained non-invasively with a high degree of accuracy.