Influence of body size and left ventricular ejection dynamics on total arterial compliance determined using Doppler echocardiography and subclavian artery pulse tracings in healthy humans.

The aim was to investigate determinants of total arterial compliance in healthy humans. Estimates of aortic root pressures and flow were obtained non-invasively with the calibrated subclavian artery pulse tracing and Doppler echocardiography in 37 males (27-76 years) and 45 females (20-77 years). Total arterial compliance, estimated using a three-element vascular model, correlated positively with body height (r = 0.45, p < 0.01) and acceleration time of aortic root flow (r = 0.32, p < 0.01) and inversely with age (r = -0.34, p < 0.05), heart rate (r = -0.33, p < 0.01), and mean arterial pressure (r = -0.51, p < 0.01). Multivariate analysis indicated that height and heart rate contributed most to the prediction of total arterial compliance. The inclusion of mean arterial pressure within the model significantly reduced the contribution of age, but not that of body height and heart rate. After adjustment for height and heart rate, total arterial compliance did not differ significantly between gender. Thus, total arterial compliance, as assessed in this study, seems to reflect both arterial capacity and viscoelastic properties of the arterial wall. Differences in body size, heart rate and mean arterial pressure should be considered when comparing total arterial compliance in different groups.