Ascending aorta distensibility abnormalities in hypertensive patients and response to nifedipine administration.

PURPOSE

The purpose of the present investigation was to study the distensibility of the ascending aorta in patients with arterial hypertension and normal subjects before and after administration of a calcium antagonist, nifedipine.

PATIENTS AND METHODS

The distensibility of the ascending aorta was measured before and after nifedipine administration in 22 male hypertensive patients and 12 age-matched male normotensive subjects. Aortic distensibility was calculated as a function of changes in aortic diameter and pulse pressure, using the formula: 2 x (pulsatile change in aortic diameter)/[(diastolic aortic diameter) x (aortic pulse pressure)]. Aortic diameters were measured by echocardiography and aortic pressures were obtained by catheterization of the ascending aorta.

RESULTS

In the basal state, the distensibility of the ascending aorta and aortic strain were lower in hypertensive patients than in normotensive subjects (p < 0.001); the lower aortic distensibility, however, was associated with a greater distending pressure. A good inverse correlation (r = -0.81) was found between mean aortic pressure and aortic distensibility. The aortic distensibility was increased after nifedipine administration in both groups; this increase in aortic distensibility, however, was lower in the patients with hypertension compared with normotensive subjects (p < 0.001).

CONCLUSIONS

Aortic distensibility is decreased in patients with arterial hypertension. Nifedipine administration increased the distensibility of the ascending aorta both in patients with arterial hypertension and in normotensive subjects. The increase of aortic distensibility after nifedipine administration was lower in hypertensive patients.