Minoru Nihei

Altered circadian blood pressure rhythm in patients with Cushing's syndrome.

The circadian blood pressure rhythm was compared in patients with Cushings syndrome, essential hypertension, and primary aldosteronism. In patients with essential hypertension or primary aldosteronism, a clear nocturnal fall in systolic and diastolic blood pressure and heart rate was observed. This fall was seen in untreated subjects as well as in patients receiving combined treatment with a calcium antagonist, diuretic, converting enzyme inhibitor, alpha-blocker and beta-blocker, or sympatholytic drug. In these groups, there was a positive correlation between heart rate and systolic or diastolic blood pressure. On the other hand, in patients with Cushings syndrome, there was no nocturnal fall in blood pressure but in some patients a rise was observed. In all patients there was a nocturnal fall in heart rate. Thus, there was no significant correlation between heart rate and blood pressure in these patients. Exogenous glucocorticoid eliminated the normal nocturnal fall of blood pressure in patients with chronic glomerulonephritis or systemic lupus erythematosus. These results suggest that the changed circadian blood pressure pattern in patients with Cushings syndrome is not due to antihypertensive treatment or to the mineralocorticoid excess accompanying this disease, but it is attributable to excess glucocorticoid or the associated disturbance in the adrenocorticotropic hormone-glucocorticoid system (or both). This conclusion also implies that the normal circadian rhythm of blood pressure may be regulated at least in part by the adrenocorticotropic hormone-glucocorticoid system.

Exogenous glucocorticoid eliminates or reverses circadian blood pressure variations.

The effect of glucocorticoid on circadian variations of blood pressure was examined. In untreated patients with essential hypertension, a clear nocturnal fall in blood pressure and heart rate was observed and this was unaffected by combined treatment with antihypertensive drugs. The circadian blood pressure variation in patients with chronic glomerulonephritis (CGN) not receiving glucocorticoid treatment was essentially the same as that in patients with essential hypertension. In both groups there was a positive correlation between blood pressure and heart rate. On the other hand, in patients with CGN and systemic lupus erythematosus (SLE) who were treated with glucocorticoid, there was no nocturnal fall in blood pressure, and often a significant rise. In these patients the blood pressure was lowest in the afternoon and began to rise from then, and during the night, attaining a peak level in the morning. Despite this changed pattern of blood pressure variations, the heart rate in these patients was clearly reduced at night. In 10 patients with CGN and SLE, circadian rhythm of blood pressure and heart rate was examined before and during treatment with prednisolone (40.2 ± 17.0mg/day for 58.0 ± 19.4 days, mean ± s.d.). Prednisolone abolished the nocturnal fall of blood pressure, while the nocturnal fall of heart rate remained. There was no correlation between blood pressure and heart rate in patients with glucocorticoid treatment. These results suggest that the circadian blood pressure variation is influenced by the hypothalmo-pituitary-adrenal axis, probably through its action on the autonomic nervous system.

A Finger Volume-Oscillometric Device for Monitoring Ambulatory Blood Pressure: Laboratory and Clinical Evaluations

A new portable device for the indirect measurement of ambulatory blood pressure in the finger was successfully applied to normotensive and hypertensive subjects in and outside a ward setting. The device uses the volume-oscillometric technique and, equipped with a microprocessor, permits long-term ambulatory monitoring of indirect systolic and mean blood pressure at desired intervals (once every 1-10 min). Systolic and mean blood pressures obtained by this method were well correlated with those measured by the direct (Oxford) and arm-cuff methods. Systolic and diastolic blood pressure obtained by the volume-oscillometric device were almost identical with those recorded by an arm-cuff. Systolic blood pressure obtained by the volume oscillometric method was, however, significantly lower than that measured by the direct method. The new device has also been used to measure blood pressure during treadmill exercise and ice-water immersion. Mean values of blood pressure and the SD of these averaged for 24 hours, or for every hour, were reproducible when the measurements were repeated under the same condition. The present device is portable, causes minimal noise, can detect rapid change in blood pressure and causes less discomfort when compared to the conventional arm-cuff method. Regular measurements can be made with minimal sleep disturbance. This fully automatic volume-oscillometric device allows reliable 24-hour monitoring of ambulatory blood pressure not only in but also outside a ward setting, and as such is useful for studies of hypertension.

Effect of weight loss on blood pressure and drug consumption in normal weight patients.

The effect of weight loss on blood pressure and on antihypertensive drug consumption was examined in 81 nonobese subjects with essential hypertension who had been chronically treated with antihypertensive drugs. A hypocaloric diet was prescribed for 5 months. A weight loss greater than 2 kg in 5 months was considered significant. Quality and quantity of antihypertensive medications were scored according to a formula. In the subjects whose medication and weight did not change, mean arterial pressure remained unchanged, whereas it decreased significantly (-7.1 +/- 1.9 mm Hg) in those who showed significant weight loss (-3.28 +/- 0.34 kg) with no change in medication. Among the subjects whose antihypertensive medication remained constant during the diet program there was a significant correlation between the change in weight and mean arterial pressure (r = 0.45, p less than 0.01). Mean arterial pressure increased significantly (+5.1 +/- 1.7 mm Hg) in subjects whose weight remained unchanged with a decrease in medication, whereas it remained significantly lower than the control (by -3.1 +/- 2.0 mm Hg) in those whose weight decreased significantly (-4.57 +/- 0.69 kg) with the decrease in medication. The weight loss-induced decrease in blood pressure occurred independently of the initial degree of obesity and the initial level of mean arterial pressure. Urinary sodium excretion in the control period and at the end of the diet program did not differ significantly between subgroups. These results indicate that, even in subjects of normal weight with essential hypertension, weight loss can induce a fall in blood pressure that leads to a reduction of antihypertensive medication.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of age on the nocturnal fall of blood pressure and its modulation by long-acting calcium antagonists

The clinical significance of the nocturnal fall of blood pressure (BP) was examined. BP was monitored every 5 min for 24 hrs by means of a finger volume oscillometric device. The nocturnal fall was observed in all age groups (young: less than 40, n = 49; adult: 40 less than or equal to less than 60, n = 110; old: 60 less than or equal to, n = 33). The amplitude of nocturnal fall of BP (averaged daytime blood pressure--averaged nighttime blood pressure) in old patients (systolic = 13 +/- 11, diastolic = 10 +/- 8 mmHg, mean +/- SD) was similar to that in the young patients (systolic = 11 +/- 8, diastolic = 10 +/- 8 mmHg). These 192 subjects were also classified according to mean BP level (MBP) averaged for daytime in the ambulatory blood pressure monitoring records [MBP less than 85 (mmHg), n = 31; 85 less than or equal to MBP less than 100, n = 72; 100 less than or equal to MBP less than 115, n = 49; 115 less than or equal to MBP, n = 25]. BP level did not affect the pattern of circadian variation in the normal subjects or in the essential hypertensive patients at WHO stage I or II. The amplitude of the nocturnal fall in systolic BP increased with the increase in BP level, but this was not the case with diastolic BP (mean daytime BP less than 85 mmHg: systolic = 11 +/- 8, diastolic = 8 +/- 6 mmHg; 85 less than or equal to less than 100: systolic = 14 +/- 8, diastolic = 11 +/- 6 mmHg; 100 less than or equal to less than 115: systolic = 17 +/- 9, diastolic = 11 +/- 8; 115 less than or equal to: systolic 17 +/- 8, diastolic = 11 +/- 6 mmHg). Nitrendipine (8.6 +/- 5.6 mg, 22.5 +/- 11.4 days, n = 14) and nisoldipine (9.3 +/- 6.2 mg, 21.5 +/- 11.4 days, n = 15) administered once daily in the morning or nifedipine slow release tablet, 20 mg twice daily (n = 15, 17.7 +/- 5.2 days) induced a significant downward shift in the circadian BP pattern, in other words, the hypotensive effect was also observed during the night when the BP had already been low. Taken together, the information on the nocturnal behavior of BP would be valuable, especially in treating aged patients with essential hypertension with a long-acting antihypertensive drug.