Cuff and ambulatory blood pressure in subjects with essential hypertension.

Clinic cuff blood-pressure measurements, obtained on at least three occasions, were compared with mean arterial pressures in 59 patients with borderline or essential hypertension who underwent direct ambulatory monitoring of blood pressure. In 22 patients (group I) mean cuff and ambulatory pressures were similar (+/- 10 mm Hg) while in 32 subjects (group II) cuff pressures were more than 10 mm Hg higher. Groups I and II could not be distinguished on the basis of clinical examination, indices of sympathetic nerve activity, or blood-pressure variability, or by the magnitude of pressure rise during physical or mental exercise. Group II had less cardiovascular target organ damage and better baroreflex sensitivity but there was considerable overlap. There was no reliable way of telling which subjects would have lower ambulatory than cuff pressures. 20 out of 59 subjects classified as hypertensive by cuff measurements had awake ambulatory pressures or less than 140/90 mm Hg.