Compliance changes in physiological and pathological states.

AIM

Although arterial compliance has been estimated by a variety of methods none of them can be directly validated because it is difficult to measure arterial volume. Moreover, because arterial pressure-volume relationships are non-linear, compliance is pressure-dependent. We have developed a method of estimating arterial compliance based on the Windkessel model of the arterial system that can account for the pressure-dependence of compliance.

RESULTS

Compared to normotensive humans, compliance was decreased in hypertension and normalized with alpha-blockade, angiotensin converting enzyme inhibition and vasodilators, but not with beta-blockade. Compliance changes with aging, exercise and some diseases were determined.

CONCLUSION

The decreased compliance seen in hypertension was due to an intrinsic change in the arterial wall, most likely due to increased smooth muscle tone.