Evaluation of the elasticity and characteristic impedance of the ascending aorta in man

Abstract
In 30 patients, simultaneous measurements of ascending aortic pressure and diameter were performed, allowing one to evaluate: (1) the influence of age, the aortic diastolic pressure, and the radius on the aortic elasticity; (2) the correlations between characteristic impedance of the aorta (Zo), systemic arterial resistance, age and diastolic aortic pressure; and (3) the importance of Zo when comparing two indices of left ventricle performance; one during isovolumic phase ([dP/dt]/Pt) max and the other during the outflow phase (maximum acceleration of aortic blood flow).