Pulse pressure in sustained essential hypertension: a haemodynamic study.

Central and forearm haemodynamics were studied in 73 middle-aged male subjects: 14 normotensive controls and 59 patients with sustained essential systolic/diastolic hypertension. Hypertensives were divided into two groups: pulse pressure within the normal range (40-60 mmHg; group I) or above 60 mmHg (group II) for the same level of mean arterial pressure (MAP). Indices of systemic and forearm arterial compliance and distensibility for the same age and MAP were reduced to the same extent in group I and II. In contrast, the peak systolic blood flow velocity of the brachial artery, cardiac output (CO) and stroke volume (SV) were significantly greater in group II than in group I. Systemic and forearm vascular resistances were significantly increased in group I but remained within the normal range in group II. The study provided evidence that, in middle age, there is a group of hypertensive patients characterized by a disproportionate increase in pulse pressure for the level of MAP. The elevation of the pulsed component of blood pressure (BP) reflects a relative hyperkinesia with an increase in CO and arteriolar vasodilatation. The subsequent increase in systolic pressure is produced by a combination of reduced arterial distensibility and increased SV.