24-hour blood pressure in primary and secondary hypertension

The blood pressure is subject to physiological day-night fluctuations, which can be attenuated in secondary hypertension as well but not in essential hypertension. In this study, the blood pressure profile over 24 hours was determined in a large collective of patients with primary and secondary hypertension for comparison to assess the relevance of ambulatory blood pressure monitoring in secondary hypertension. There were 88 patients with essential hypertension (age 20 to 73 years) and 80 patients with secondary hypertension (age 19 to 70 years) with a mean blood pressure value from 8 a.m. to 8 p.m. greater than 135 mm Hg. Blood pressure and heart rate were monitored for 24 hours. In 58/80 patients with secondary hypertension renal parenchymal disease was present, 14 had renovascular disease, three had Cushing's syndrome, four had primary hyperaldosteronism and one had a pheochromocytoma. Of the 88 patients with essential hypertension 67, and of the 80 patients with secondary hypertension 69 were on antihypertensive treatment. The measurements were carried out with a portable automatic ambulatory monitor unit (SpaceLabs 90202) between 6 a.m. and midnight at intervals of 15 minutes and from midnight to 6 a.m. at intervals of 30 minutes. The duration of sleep was documented. In patients with secondary hypertension, as compared with patients with essential hypertension, there were higher blood pressure values during the night from 8 p.m. to 8 a.m., and during sleep (Table 1). The profile of the hourly mean values for systolic and diastolic blood pressure (Figure 1) shows that patients with secondary hypertension, as compared with patients with essential hypertension, have a clearly diminished blood pressure reduction during the night.(ABSTRACT TRUNCATED AT 250 WORDS)