Measurements of base blood pressure during sleep and its clinical significance in hypertensive patients.

The intra-arterial blood pressure (BP) was measured during 24 hours on 52 patients with essential hypertension using a portable device. The minimum BP inherent to each subject (base BP) was determined from the systolic and diastolic BP histograms during sleep. In this study the systolic and diastolic BPs were presented as a mean BP (BP) and a base BP, and the average of BPs during waking hours was considered as the sum of the base BP and the additional BP increment. The clinical significance of the base BP and BP increment was examined by comparing them with the results of clinical examinations. The comparison showed that the base BP was closely related with the left ventricular hypertrophy and severity of hypertension, while the BP increment correlated with the baroreflex sensitivity and plasma norepinephrine concentration. In this paper, a new tonometry was developed to indirectly record the BP of the superficial temporal artery. The tonometry correlated well with the intra-arterial BP measurement, and was available for the indirect base BP evaluation at an outpatient-clinic.