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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Percutaneous transluminal dilatation of a left sided renal artery stenosis was performed in a 61 year old patient with hypertension. Biochemical and hemodynamic activity of the renal artery stenosis was demonstrated by measurement of renal venous renin-activity and determination of renal plasma flow and of pre- and poststenotic blood pressure values. Shortly after the dilatation procedure hypertension disappeared and renal plasma flow increased. The described procedure might be an alternative method to renal vascular surgery.
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PMID:Percutaneous transluminal dilatation: a new treatment of renovascular hypertension? 67 42

A patient had unilateral renal artery stenosis and, at the same time, bilateral polycystic kidney disease. The renal venous renin ratio of 151:40, together with a high peripheral plasma renin activity, indicated that the hypertension was partially caused by renopressor mechanism. Correction of the obstructive lesion permitted a better control of hypertension with antihypertensive drugs, and the peripheral and renal venous renin activity returned to normal. The success in detecting one pathogenic mechanism responsible for arterial hypertension should not deter further diagnostic efforts.
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PMID:Renal artery stenosis and polycystic kidney disease. 67 87

Pressor responses to norepinephrine (NE) infusions were examined in normal rabbits, in rabbits with renal artery stenosis of over 30 days' duration (chronic renal hypertensive rabbits), and in rabbits with renal artery stenosis of 3 days' duration (3-day clipped rabbits). The 3-day clipped rabbits did not have hypertension, but they showed the same increased pressor responses to NE as did the chronic renal hypertensive rabbits, which was about 2.5 times that of the normal rabbits. Plasma renin activity (PRA) was the same in the 3-day clipped rabbits as in the normal group, but in the chronic renal hypertensive rabbits the PRA was significantly below normal. Infusions of angiotensin II (A II) in either subpressor or pressor amounts potentiated the pressor responses to NE in normal rabbits, whereas, in 3-day clipped rabbits and chronic renal hypertensive rabbits, A II in subpressor or pressor doses did not alter the pressor responses to NE. Infusion of the A II antagonist, [1-sarcosine, 8-isoleucine]angiotensin II, did not alter the pressor responses of normal rabbits to NE, but this A II analogue completely abolished the pressor hyperresponsiveness to NE in the 3-day clipped rabbits and greatly reduced the NE hyperresponsiveness in the chronic renal hypertensive rabbits; this A II antagonist did not alter the control arterial pressure in any of the three groups of rabbits. These studies show that the increased pressor response to NE in rabbits with renal artery stenosis occurs before the onset of hypertension and thus is not merely a result of the hypertension. Also, these results provide evidence that A II plays an important role in the increased pressor responses to NE in hypertensive and prehypertensive rabbits.
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PMID:Pressor responses to norepinephrine in rabbits with 3-day and 30-day renal artery stenosis. The role of angiotensin II. 67 26

Over an 18-month period nine infants in a neonatal intensive care unit developed hypertension (blood pressure, 115/88 to 280/140 mm Hg) at 2 to 45 days of age. Eight of the nine infants had indwelling umbilical artery catheters prior to onset of hypertension; six of the nine infants had evidence of a patent ductus arteriosus. Peripheral plasma renin activity was greater than 300 ng/ml/3 hr in six of eight infants. Angiograms were abnormal in six of seven infants and computerized renal scans were abnormal in all nine infants. One infant had congenital renal artery stenosis. Eight of nine infants had evidence of unilateral or bilateral renal artery thrombi which were felt to have emanated from an umbilical artery catheter or a ductus arteriosus. Hypertension in all infants was successfully controlled medically (follow-up of 3 to 27 months; mean, 14.4 months). Blood pressures remained normal when medication was discontinued. In our experience, neonatal renovascular hypertension is no longer uncommon, responds to aggressive medical management, and rarely requires early nephrectomy. Neonatal renovascular hypertension was usually associated with umbilical artery catheters positioned above the level of the renal arteries.
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PMID:Nonsurgical management of renovascular hypertension in the neonate. 68 86

A new method was developed for separate kidney function studies by catheterizing the ureters and exteriorizing the catheters through the urethra into the vagina. Renal artery plication was performed to reduce blood flow to one kidney by 66 +/- 5%. Arterial pressure increased from 107 +/- 2 to 131 +/- 3 mmHg and remained elevated for 28 days. Plasma renin activity was increased for the first 7-10 days only. Sodium and water excretion were markedly reduced in the kidney with the stenosed renal artery and after the first 2 days Na and water excretion were incresed in the contralateral kidney. These changes in Na and water excretion were frequently associated with similar directional changes in glomerular filtration rate (GFR) and renal plasma flow. An exception was noted in that renal sodium and water excretion remained low throughout the 28 days in the kidney with the constricted renal artery, whereas GRF returned to near the control level by the end of 2 wk. Altered filtration fraction did not appear to be a determining factor in control of the rate of Na excretion. It is suggested that GFR, the renin-angiotensin-aldosterone system, and other as yet undefined factors are involved in salt and water homeostasis during unilateral renal artery stenosis with hypertension.
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PMID:Separate renal function studies in conscious dogs with renovascular hypertension. 69 70

From our consecutive series of renal vein renin studies in 170 patients with kidney disorders and hypertension, we present those cured by surgical correction of a unilateral renal artery stenosis during the period 1973--75. The renin secretion patterns of these patients range between no demonstrable abnormality, even with a stimulating procedure using dihydralazine 7.5 i.v., and massive renin secretion already during basal conditions. Thus, the renin secretion may not be increased even after stimulation in some patients with durable unilateral renovascular hypertension. This fact may be explained by the rise of the systemic blood pressure, eventually maintained by sodium and water retention and accompanied by adaptive changes in the contralateral kidney. The perfusion pressure is thereby kept normal in the affected kidney, eliminating a stimulus for renin secretion. It is likely that many cases of renovascular hypertension pass through an early stage where no involvement of the renin-angiotensin system may be discovered. Of course, these patients will also benefit from surgery. The conclusion is that renin studies for diagnostic purposes should be performed when patients are on treatment and kept normotensive for some time, and that an additional challenge of the perfusion pressure, i.e., by use of dihydralazine, intravenously should be performed.
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PMID:Observations on the use and limitations of renal vein renins in hypertensive patients. 69 82

Three types of renal hypertension in the rat have been compared with respect to blood pressure increase, activity of the RAS, and secretion of aldosterone and corticosterone: type I - unilateral stenosis of the renal artery in the presence of an intact contralateral kidney; type II - unilateral stenosis of the renal artery after contralateral nephrectomy; type III - bilateral stenosis of the renal arteries. Blood pressure rose more rapidly and reached higher values in type II and type III hypertension than in type I hypertension. In the latter group, the activity of the RAS was more stimulated than in types II and III. The marked stimulation of the RAS in type I hypertension is ascribed to the negative fluid and sodium balance, which is the consequence of a pressure-induced diuresis of the unclamped contralateral kidney. Suppression of the activity of the RAS by a 4-week pretreatment with DOC-TMA and saline or by the administration of DOCA and saline as from the induction of renal artery stenosis did not prevent the development of hypertension caused by the clamping of one renal artery (type I). In spontaneously hypertensive rats of the stroke-prone substrain, high dietary salt intake caused higher blood pressure values and a higher incidence of cerebral lesions than normal dietary salt intake. Low salt intake was followed by a marked stimulation of the RAS, but blood pressure rose only slightly and no symptoms of cerebrovascular lesions were observed. It is concluded that neither in hypertension induced by renal artery stenosis nor in spontaneously hypertensive rats, the RAS contributes significantly to the increase in blood pressure nor does it play a major part in the pathogenesis of vascular lesions. These seem to be related to the retention of sodium, which may be obtained by renal artery stenosis, by excessive salt intake, or by the administration of a mineralocorticoid and salt.
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PMID:What makes the renin-angiotensin system a pathogenic factor? 69 4

Washout urography was used as a screening test for 100 hypertensive patients. Eleven patients had renal hypertension. These were 4 cases of unilateral renal artery stenosis, 6 cases of unilateral pyelonephritis and one case of bilateral pyelonephritis with atherosclerosis of the right renal artery. The increase in size of the affected kidneys after Lasix injection was much restricted relatvie to the normal contralateral kidneys. The test proved valuable for screening cases of renovascular hypertension and unilateral pyelonephritis.
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PMID:Washout urography in the diagnosis of renal hypertension. 70 Sep 44

We report on 15 patients operated upon for renovascular hypertension associated with bilateral renal artery stenosis. Followup has been for 1 to 12 years. Four of 5 patients with positive split renal function studies and 3 of 5 patients with positive renal vein renin assays underwent unilateral operations on the positive side. All of these patients were cured or improved. The guide for unilateral operations in hypertensive patients with bilateral renal artery stenosis by angiography was the physiological information obtained from the preoperative screening tests, especially the plasma renin activity ratios of the 3 different veins and the split renal function studies.
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PMID:Surgical treatment of renovascular hypertension associated with bilateral renal artery stenosis. 71 91

Percutaneous transluminal dilatation was performed in 5 patients with unilateral atherosclerotic renovascular disease and one patient with occlusion of a renal artery. Hemodynamic activity of the stenosis was documented by determination of pre- and poststenotic blood pressure values and by measurement of renal plasma flow. Flowing transluminal dilatation all patients showed a significant drop in blood pressure and antihypertensive treatment could be reduced or even discontinued. Only one patient became hypertensive again 3 months after the dilatation procedure. In this patient both the reduction of renal plasma flow and the delayed nephrographic effect on the stenotic side in the intravenous urogram were interpreted as symptoms of a recurrence of significant renal artery stenosis. In 2 of the six patients with impaired kidney function glomerula filtration are increased, as documented by a decrease in serum creatinine values. The results show that percutaneous transluminal dilatation may be a valuable method in the management of renovascular hypertension.
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PMID:[Renovascular hypertension: therapy by means of percutaneous transluminal dilatation of renal artery stenoses]. 71 24


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