Hemodynamic studies in patients with borderline blood pressure elevation.

Ninety-four patients with occasionally elevated (borderline) blood pressure, 61 patients with asymptomatic established hypertension, and 63 normal subjects have been studied at rest and during a progressive exercise test on a cycle ergometer. Subjects with borderline blood pressure had increased cardiac output in the resting recumbent position, but this was not maintained in the sitting position or during exercise. In the resting recumbent position there was overlap in the total peripheral resistance of normal subjects and patients with borderline blood pressure, but when analyzed in relation to the cardiac output, the total peripheral resistance of patients with borderline blood pressure was significantly elevated. In the sitting position the peripheral resistance of the patients with borderline blood pressure was elevated and remained elevated during light exercise, but fell into the normal range at higher loads. In this respect patients with borderline blood pressure differed from hypertensive patients who maintain a higher peripheral resistance than the normal subjects do at all levels of exercise. In conclusion, patients with occasional elevation of blood pressure have an abnormal peripheral resistance in relation to cardiac output both at rest and at low levels of exercise. This observation may indicate a prehypertensive state.