Influence of aging on arterial compliance.

With aging, pulse pressure increases. A high pulse pressure has been recognised as an important cardiovascular risk factor. The increase in pulse pressure with aging is mainly due to a decrease in large artery compliance. Compliance and distensibility are large artery wall properties. Compliance is the buffering capacity of the vessel. Distensibility reflects much more the elasticity of the artery. Compliance is related to distensibility and arterial diameter. These large artery wall properties can be measured non-invasively using new echo-tracking techniques. With these techniques it has been shown that the elasticity (distensibility) and the buffering capacity (compliance) of the common carotid artery is decreasing with aging, while diameter of the artery increases. This increase in diameter might be a compensating mechanism to limit the decrease in compliance. There are indications that the effect of aging on large artery wall properties may not be similar at all vascular territories. A decrease in compliance leads to a high pulse pressure and isolated systolic hypertension. The drug of choice for the treatment of isolated systolic hypertension should increase large artery compliance with no, or only minor effect on resistance vessels. This would lead to a decrease in pulse pressure without decreasing mean blood pressure. As a result, systolic but not diastolic blood pressure decreases. It appears that nitrates better than other anti-hypertensive drugs can decrease pulse pressure. They therefore have been advocated for the treatment of isolated systolic hypertension.