Blood Pressure Control in End-Stage Renal Disease in Man: Indirect Evidence of a Complex Pathogenic Mechanism besides Renin or Blood Volume

1977 ◽  
Vol 52 (1) ◽  
pp. 19-21
Author(s):  
G. Cannella ◽  
A. Castellani ◽  
G. Mioni ◽  
M. Usberti ◽  
U. Guerra ◽  
...  

1. In twenty-three uraemic patients on regular dialysis, plasma renin activity and blood volume were measured before and after a single dialysis. Three groups were identified; the first had a low or normal plasma renin activity and a high or normal blood volume, the second had a high plasma renin activity and a low blood volume and the third had both variables above normal. 2. In spite of these differences, diastolic blood pressure before and after dialysis was the same in the three groups and multiple regression analyses failed to demonstrate any dependence of blood pressure on plasma renin activity, blood volume or body weight taken separately or together. 3. We conclude that other factors besides plasma renin activity and blood volume are important in maintaining arterial hypertension in terminal renal failure.

1982 ◽  
Vol 63 (2) ◽  
pp. 121-125 ◽  
Author(s):  
S. Swart ◽  
R. F. Bing ◽  
J. D. Swales ◽  
H. Thurston

1. Plasma renin activity, body weight and blood pressure were measured before and after 7 days' treatment with bendrofluazide in ten hypertensive subjects. They were then treated with bendrofluazide alone (5 mg daily) for a minimum of 3 years. The diuretic was then discontinued and the measurements were repeated before and again after 7 days with bendrofluazide. The results were compared with those obtained before chronic treatment with the diuretic. 2. Chronic diuretic treatment was associated with a persistent and progressive rise in plasma renin activity, that fell promptly to pretreatment levels when diuretics were discontinued. This was associated with significant weight gain but no immediate significant rise in blood pressure. 3. When acutely challenged with bendrofluazide the patients showed a greater increase in plasma renin activity on the second occasion than on the first. Three out of five patients with an initially subnormal response had normal responses after chronic diuretic treatment. 4. Chronic diuretic treatment increased the responsiveness of the juxtaglomerular apparatus in some hypertensive patients. 5. Classification of hypertensive patients into renin subgroups may be influenced by previous therapy, even when that therapy has been discontinued for 4 weeks. In particular ‘low renin hypertension’ may be masked by recent use of diuretics, as shown by three of the five patients in this subgroup in the present study.


1978 ◽  
Vol 54 (1) ◽  
pp. 75-83 ◽  
Author(s):  
P. Van Hoogdalem ◽  
A. J. M. Donker ◽  
F. H. H. Leenen

1. Angiotensin II blockade before and after marked sodium depletion in patients with hypertension [unilateral renovascular (eight), bilateral renovascular (four) and essential (four)] was performed by intravenous administration of the angiotensin II antagonist Sar1-Ala8-angiotensin II (saralasin). 2. On normal sodium intake, saralasin decreased mean blood pressure by 8 mmHg in the unilateral renovascular group, by 6 mmHg in the bilateral renovascular group and increased it by 3 mmHg in the essential hypertensive group. After sodium depletion saralasin decreased mean blood pressure by 33 mmHg, 35 mmHg and 18 mmHg respectively. The saralasin-induced decrease in blood pressure significantly correlated with the log of the initial plasma renin activity. 3. Saralasin infusion decreased effective renal plasma flow (ERPF) in all three hypertension subgroups, both on normal sodium intake and after sodium depletion. Glomerular filtration rate decreased in direct relation to the hypotensive effect of saralasin but ERPF showed this relationship only after sodium depletion. On normal sodium intake saralasin increased filtration fraction by 17%, but decreased it by 7% after sodium depletion. 4. It is concluded that the hypotensive action of saralasin closely correlates with the value of circulating plasma renin activity, apparently independent of the aetiology of the hypertension. The decrease in ERPF during saralasin infusion in the patients on normal sodium intake seems mainly related to the agonistic activity of saralasin, but that after sodium depletion to the hypotensive effect of saralasin.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Lucia La Sala ◽  
Elena Tagliabue ◽  
Elaine Vieira ◽  
Antonio E Pontiroli ◽  
Franco Folli

Abstract Background Information about the renin–angiotensin–aldosterone system (RAAS) in obese individuals before and after bariatric surgery is scarce. Aim of this study was to analyze the RAAS in severely obese subjects, in relation to anthropometric and metabolic variables, with special reference to glucose tolerance. Methods 239 subjects were evaluated at baseline, and 181 one year after bariatric surgery [laparoscopic gastric banding (LAGB)]. Results At baseline, renin (plasma renin activity, PRA) was increased from normal to glucose tolerance and more in diabetes, also correlating with ferritin. After LAGB, the decrease of PRA and aldosterone was significant in hypertensive, but not in normotensive subjects, and correlatied with decrease of ferritin. PRA and glucose levels were predictive of persistent hypertension 1 year after LAGB. Conclusions These data support the role of RAAS in the pathophysiology of glucose homeostasis, and in the regulation of blood pressure in obesity. Ferritin, as a proxy of subclinical inflammation, could be another factor contributing to the cross-talk between RAAS and glucose metabolism.


2000 ◽  
Vol 10 (4) ◽  
pp. 353-357 ◽  
Author(s):  
Michael Hauser ◽  
Andreas Kuehn ◽  
Neil Wilson

AbstractBackgroundDespite successful surgical repair of aortic coarctation, life expectancy is reduced, and up to one-third of patients remain or become hypertensive. So as to characterize the responses for blood pressure, we have studied 55 patients with surgically repaired coarctation. Their mean age was 11.3 ± 5.97 years. We documented maximal uptake of oxygen, anaerobic threshold, plasma renin activity and blood pressures during a Bruce protocol treadmill test. The velocity across the site of repair as imaged by crosssectional echocardiography was measured before and after exercise. We measured the changes in heart rate and blood pressure subsequent to an infusion of 1 ug per kg of isoprenalin, monitoring blood pressure over 24 hours in all patients.ResultsWhen compared with 40 healthy age-matched controls, the patients with coarctation had a normal exercise capacity. Resting systolic blood pressures above the 95th percentile were present in 45% of the patients. Exercise-induced hypertension, and an elevation in the average systolic 24 hour blood pressures, were observed, but less frequently than elevated baseline values, suggesting that socalled white-coat” hypertension may be present in this population. Abnormal reactions and elevation of plasma renin activity were related to a history of paradoxical hypertension at the time of surgery. Attenuation of the circadian rhythm for blood pressure was a frequent finding, and may have implications in the development of long-term damage to end-organs. A high correlation was found between mean systolic blood pressure measured by 24 hour monitoring and left ventricular hypertrophy (r=0.65, p<0.05).ConclusionsAbnormalities in blood pressure occurred independently of significant mechanical obstruction. Despite successful surgical repair, abnormalities in the shape of the aortic arch, reduced sensitivity of baroreceptor reflexes, and neurohumoral factors may all contribute to the development of hypertension.


1983 ◽  
Vol 64 (2) ◽  
pp. 141-152 ◽  
Author(s):  
J. Brod ◽  
J. Bahlmann ◽  
M. Cachovan ◽  
P. Pretschner

1. Central and peripheral haemodynamics, circulating blood volume and plasma renin activity (PRA) were investigated under resting conditions in 97 patients with chronic nonuraemic renal parenchymatous disease and without anaemia. For comparison a group of 17 healthy subjects was used. 2. An initial abnormality appeared in 12 out of 32 normotensive renal patients. It consisted of a markedly increased circulating blood volume, raised cardiac output, low total peripheral and forearm vascular resistance, hyperfusion of the forearm and increased venous distensibility. PRA was slightly (but insignificantly) higher in these hyperkinetic subjects with relaxed peripheral vessels than in the other 20 normotensive renal patients who did not differ haemodynamically from the control subjects. 3. Fifteen out of 47 renal patients with a mild or moderate hypertension (stage I–II WHO) were hyperkinetic. However, in these there was no compensatory vasodilatation in response to the high cardiac output: forearm blood flow was normal and venous distensibility below that of the control subjects. Blood volume was normal. Plasma renin activity (PRA) was the same as in the normotensive renal patients. 4. The difference between stage I–II and stage III was due entirely to a rise in total peripheral vascular resistance. 5. A re-examination of these patients 2-8 years after they had been first studied revealed that 11 out of the 12 originally hyperkinetic normotensive renal patients were now hypertensive compared with only one-half of the originally normokinetic normotensive renal subjects. 6. It is concluded that an inability of the diseased kidney to control volume homoeostasis leads to hypervolaemia, which raises cardiac output in the renal patients whilst still normotensive. As long as the arterioles adjust to the high output and the capacitance system to the high volume, blood pressure remains normal. When this adaptation of the periphery ceases, blood pressure rises, normalizing (possibly through a pressure diuresis) blood volume. PRA does not correlate with any of these changes and only in advanced renal hypertension may its rise partly contribute to the maintenance of high blood pressure without being its cause.


1985 ◽  
Vol 13 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Makoto Uchiyama ◽  
Kaoru Sakai

Na and K metabolism, and orthostatic response of blood pressure and plasma renin activity (PRA) were studied in six children, aged 10 to 15 years, with postural hypotension before and after treatment with Dihydergot®(DHE). All abnormal findings which we had already observed in children with postural hypotension (i.e. low fractional excretion of filtered Na in spite of low PRA, extremely high PRA on fainting, great postural fall in blood pressure, and so on) improved on treatment with DHE. This suggests that these abnormal physiological findings found in children with postural hypotension may result from increased venous pooling which can be reduced by DHE. Consequently, DHE seems an excellent drug to treat postural hypotension from the physiological point of view.


1989 ◽  
Vol 257 (3) ◽  
pp. R647-R652 ◽  
Author(s):  
S. M. Block ◽  
J. E. Pixley ◽  
A. H. Wray ◽  
D. Ray ◽  
K. D. Barnes ◽  
...  

Blood volume restitution after hemorrhage was investigated in lambs in the first week of life. Two groups of nonsplenectomized lambs were bled 10 and 20% of their blood volume at 2%/min while being suspended horizontally in a sling with their legs dependent, and a third group was bled 20% while lying down. Blood pressure fell 8% in the lambs bled both 10 and 20% while lying down and 44% in those bled 20% while being suspended. Blood volume was completely restored in all three groups by 5 h after the hemorrhage, the rate of restitution being equal among the groups. The initial phase of restitution was slower when the lambs were bled while lying down. Vasopressin levels were increased only in the lambs bled 20% of their blood volume while being suspended. Plasma renin activity increased similarly in all groups. Hemorrhage increased plasma glucose but did not change plasma protein and serum osmolality. We conclude that lambs bled up to 20% of blood volume restitute relatively quickly at a rate independent of the volume shed. The position of the animal affects the degree of hypotension, the levels of vasopressin, and the rate of the initial phase of volume restoration.


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