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

We describe a 17-year-old hypertensive man with a left abdominal mass on the computed tomographic scan. Radiologic studies revealed a large tumor near the left renal hilus, resulting in renal compression and displacement toward the posterolateral abdominal cavity. Aortography excluded stenosis of the renal arterial vessels. Plasma and urinary catecholamines were normal and plasma renin activity (PRA) was high. The left renal vein renin was 2.1-fold higher than the right one. After resecting the tumor including the left kidney and adrenal, high blood pressure and elevated PRA returned to normal. Histologically, the tumor was a paraganglioma, and the affected kidney showed hyperplasia of the juxtaglomerular apparatus. Thus, the hypertension in our patient was probably due to renal ischemia extrinsically compressed by a non-functioning retroperitoneal paraganglioma (Page kidney).
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PMID:Hypertension and unilateral renal ischemia (Page kidney) due to compression of a retroperitoneal paraganglioma. 891 22

In human essential hypertension, and in all forms of experimental hypertension studied thus far, volume regulation and the relationship between blood pressure (BP) and sodium excretion (pressure natriuresis) are abnormal. Considerable evidence indicates that resetting of pressure natriuresis plays a key role in causing hypertension, rather than merely occurring as a consequence of increased BP. In patients with essential hypertension, resetting of pressure natriuresis is characterized either by a parallel shift to higher BPs and salt-insensitive hypertension, or by a decreased slope of pressure natriuresis and salt-sensitive hypertension. This clearly indicates that essential hypertension cannot be ascribed to a single abnormality of kidney function. Multiple physiological studies have shown that salt-sensitive hypertension can be elicited by renal abnormalities that cause either loss of functional kidney mass or an inability to modulate the renin-angiotensin-aldosterone (RAA) system appropriately; these abnormalities include loss of functional nephrons, decreased glomerular capillary filtration coefficient, patchy renal ischemia, and increased distal and collecting tubular reabsorption. Renal abnormalities that cause salt-insensitive hypertension are characterized by normal functional kidney mass, and the ability to appropriately modulate the renin-angiotensin system during changes in sodium intake; important causes of salt-insensitive hypertension include widespread increases in preglomerular resistance and increased reabsorption in the proximal tubules and loops of Henle. By comparing the characteristics of pressure natriuresis in essential hypertensive subjects with those found in experimental hypertension of known origin, we can gain considerable insight into the etiology of human hypertension.
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PMID:Central role of the kidney and abnormal fluid volume control in hypertension. 900 86

Midaortic syndrome (MAS) is a well-recognized but rare cause of renovascular hypertension (RVH). Several techniques have been described to treat RVH caused by MAS. The authors recently treated two children with MAS and RVH. In both patients the right kidney had two renal arteries. A 13-year-old boy presented with severe headaches, pain in his lower extremities with exertion, and marked hypertension (blood pressure, 170/110). An aortogram demonstrated 70% narrowing of his abdominal aorta from the suprarenal region to 5 cm above the iliac bifurcation. There was significant stenosis of the celiac axis, superior mesenteric artery, and left renal artery. The right kidney had two renal arteries, and the upper pole artery was stenotic at its origin. A 10-year-old girl, known to have hypertension for several years had an aortogram that demonstrated 70% narrowing of the abdominal aorta from the suprarenal region to 3 cm above the iliac bifurcation. There was involvement of the left renal artery at its orifice. She also had two renal arteries to the right kidney with the right upper pole artery being stenotic at its origin and in the mid-portion of the vessel. Aortic reconstruction was accomplished with a polytetrafluoroehtylene (PTFE) bypass graft in each case. The first case also involved patch angioplasty of the celiac axis. In both cases, the right kidney was autotransplanted. It was removed intraoperatively, cold perfused, and the two renal arteries reconstructed followed by transplantation to the right iliac vessels. In both cases the left renal artery was reimplanted into the PTFE graft. Both patients had uncomplicated postoperative courses. The 13-year-old boy had evidence of renal ischemia in a portion of the lower pole of the autotransplanted kidney by DTPA scan. He has mild hypertension controlled with antihypertensive medication. The 10-year-old girl has a normal DTPA scan and is normotensive. MAS is a rare and challenging congenital vascular anomaly that causes RVH. In the presence of double renal arteries the technique of autotransplantation with cold perfusion and "bench" vascular reconstruction reduces the warm ischemia time and should produce satisfactory results.
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PMID:Renal autotransplantation for renovascular hypertension caused by midaortic syndrome. 904 31

Contrast-media associated nephropathy (CMAN) consists in a sudden impairment of glomerular filtration rate following exposure to radiographic contrast materials. Damage may be limited to an asymptomatic mild increase of blood creatinine, or reach the highest levels of nitrogen retention compatible with acute renal failure. Some preexisting clinical conditions or pathologies may lead to CMAN: not only renal insufficiency, diabetes mellitus, multiple myeloma, congestive heart failure and severe hypertension, but also simple dehydration and a growing series of immunologic diseases are recognized as predisposing condition. The exact mechanism responsible for renal injury is still doubtful but recently animal models have shown substantial ischemic changes that may be added to the traditional presumed pathogenesis of direct tubular toxicity and intra-tubular obstruction. As renal ischemia stimulates both endogenous vasoconstrictor and vasodilator substances, it is now supposed that CMAN acts similarly to non-steroidal anti-inflammatory agents, selectively inhibiting the vasodilatory prostaglandin phase and therefore causing a derangement of the physiologic vasoconstriction/vasodilatation balance of renal circulation. The role of oxygen free radicals to contribute to renal dysfunction is considered. Low osmolality non ionic contrast media when compared to conventional high osmolality ionic contrast media have reduced but not eliminated CMAN. Simple but effective lines of prevention include the previous selection of patients predisposed to CMAN for concomitant pathology, suspension of FANS or any other recognized nephrotoxic substance, the least amount of contrast media compatible with radiologic visualization of the patient's problem, careful hydration of the patient before contrast injection and sustained diuresis afterwards. The usefulness of pre-treatment with Ca-channel blockers or atrial natriuretic factors remains sub judice.
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PMID:[Physiopathology, clinical aspects and prevention of renal insufficiency caused by contrast media]. 917 67

Little attention has been paid to nephropathies and proteinuria in renovascular hypertension (RVH). Recently there has been a growing interest in the conditions induced by RVH. 10 cases of RVH were diagnosed by angiography and renin sampling from renal veins in the last 6 years in our hospital. The patients were all male and mean age was 64 +/- 8 (SD) years. Data were as follow: protein excretion was 3.8 +/- 2.2 g/day (> or = 3.5 g/day in 8 patients), sBP 202 +/- 24 mmHg, dBP 113 +/- 17 mmHg, serum renin concentration 64 +/- 45 pg/ml, and ipsilateral/contralateral renal vein renin ratio 3.3 +/- 1.0. RVH was treated by nephrectomy in 3 patients, percutaneous transluminal renal angioplasty (PTA) in 2, and angiotensin converting enzyme inhibitors (ACE-I) administration in 8. Biopsies were performed on contralateral kidney in 4 patients. Focal segmental glomerulosclerosis (FGS) was found in 3 patients, and nephrosclerosis in 1, whereas only nephrosclerosis was found in nephrectomized kidneys in all 3 patients. After nephrectomy, PTA and the treatment by ACE-I, not only blood pressure but also proteinuria was markedly reduced. These findings suggest that severe stenosis of the renal artery led to renal ischemia, which activated renin excretion, to cause glomerular hyperfiltration through vasoconstriction of the efferent arterioles in the contralateral kidney. FGS-like lesion thus induced appeared to have caused massive proteinuria.
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PMID:Renovascular hypertension may cause nephrotic range proteinuria and focal glomerulosclerosis in contralateral kidney. 935 55

In the vast population of patients with established hypertension, there is a small group in whom the blood pressure elevation is caused by renal ischemia. These patients have renovascular hypertension, which can presently be diagnosed with greater precision than in the past. The exact prevalence of renovascular hypertension is not known and the diagnosis is probably missed in many patients. It is important to recognize this condition in clinical practice, because it is a correctable from of secondary hypertension and because it is a reversible cause of renal failure in some patients. Clinical identification of patients with renovascular hypertension has been so imprecise and complex that the very diagnostic quest for this condition has been questioned. However, it is well recognized that renovascular disease is a progressive disorder with serious sequelae if appropriate therapy is not rendered.
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PMID:Renovascular hypertension. 937 73

Ischemic renal disease (IRD) is defined as a clinically important reduction in glomerular filtration rate or loss of renal parenchyma caused by hemodynamically significant renal artery stenosis. IRD is a common and often overlooked clinical entity that presents itself in the setting of extrarenal arteriosclerotic vascular disease in older individuals with azotemia. Eleven to 14% of end-stage renal disease (ESRD) cases are attributable to chronic IRD. A high percentage of patients entering ESRD programs are hypertensive. Many patients with a presumed diagnosis of hypertensive nephrosclerosis actually have undiagnosed ischemic nephropathy as the etiology of their ESRD. It is important for the clinician to identify IRD, because IRD is a potentially reversible cause of chronic renal failure in a hypertensive patient. Atherosclerotic renal artery disease is common among patients with coronary artery disease and aortic and peripheral vascular disease. Atherosclerotic renal artery disease is a progressive disorder, and its progression is associated with loss of renal mass and functioning. A decrease in glomerular filtration rate sufficient to cause an elevation of the serum creatinine concentration requires injury to both kidneys. Consequently, IRD can arise from one of two main clinical situations: bilateral hemodynamically significant renal artery stenosis leading to bilateral renal ischemia; and hemodynamically significant renal artery stenosis in a solitary functioning kidney, or in a kidney that is providing the majority of a patient's glomerular filtration. The primary reason for establishing the diagnosis of IRD is the hope that correction of a renal artery stenosis will lead to improvement of renal function, or a delay in progression to ESRD. There are six major clinical settings in which the clinician could suspect IRD: acute renal failure caused by the treatment of hypertension, especially with angiotensin converting enzyme inhibitors; progressive azotemia in a patient with known renovascular hypertension; acute pulmonary edema superimposed upon poorly controlled hypertension and renal failure; progressive azotemia in an elderly patient with refractory or severe hypertension; progressive azotemia in an elderly patient with evidence of atherosclerotic disease; and unexplained progressive azotemia in an elderly patient. Noninvasive testing modalities that have been used recently include the angiotensin converting enzyme inhibitor renal scan, duplex Doppler sonography, magnetic resonance angiography, and the spiral computed tomography. Treatment methods include percutaneous transluminal angioplasty, endovascular stenting, and surgical revascularization. The results of treatment for preservation of renal function have been encouraging, with stabilization or improvement in renal function observed in a significant proportion of cases.
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PMID:Ischemic renal disease: an emerging cause of chronic renal failure and end-stage renal disease. 943 40

The aim of the present study was to provide an overview of the role of circulating gonadal steroids on the adaptive changes of the renin-angiotensin system to chronic hypobaric hypoxia (CHH: 4400 m simulated altitude in an hypobaric chamber) and the development of experimental hypertension by bilateral renal ischemia. In order to fulfill this goal, blood pressure (BP), plasma renin activity (PRA) and plasma angiotensinogen concentration (PAoC) as well as haematocrit (Htc) and body weight (BW) of intact and post-puberal castrated normotensive (Nt) and hypertensive (Ht) rats of both sexes were studied following an experimental design similar to that of previous works. Post-puberal castration decreased BP of Nt and Ht rats subjected to CHH. Sexual dimorphism in BP, PRA and PAoC was maintained while that in haematocrit disappeared after castration. Results suggest that circulating sexual steroid hormones are involved in the response of the renin-angiotensin system to the experimental conditions of environmental reduced O2 partial pressure.
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PMID:Effect of castration on renin-angiotensin system of hypertensive rats submitted to chronic hypobaric hypoxia (simulated altitude: 4400 m). 943 79

The pathogenesis of fibrosis and the functional features of pressure overload myocardial hypertrophy are still controversial. The objectives of the present study were to evaluate the function and morphology of the hypertrophied myocardium in renovascular hypertensive (RHT) rats. Male Wistar rats were sacrificed at week 4 (RHT4) and 8 (RHT8) after unilateral renal ischemia (Goldblatt II hypertension model). Normotensive rats were used as controls. Myocardial function was analyzed in isolated papillary muscle preparations, morphological features were defined by light microscopy, and myocardial hydroxyproline concentration (HOP) was determined by spectrophotometry. Renal artery clipping resulted in elevated systolic arterial pressure (RHT4: 178 +/- 19 mmHg and RHT8: 194 +/- 24 mmHg, P < 0.05 vs control: 123 +/- 7 mmHg). Myocardial hypertrophy was observed in both renovascular hypertensive groups. The myocardial HOP concentration was increased in the RHT8 group (control: 2.93 +/- 0.38 micrograms/mg; RHT4: 3.02 +/- 0.40 micrograms/mg; RHT8: 3.44 +/- 0.45 micrograms/mg of dry tissue, P < 0.05 vs control and RHT4 groups). The morphological study demonstrated myocyte necrosis, vascular damage and cellular inflammatory response throughout the experimental period. The increased cellularity was more intense in the adventitia of the arterioles. As a consequence of myocyte necrosis, there was an early, local, conjunctive stroma collapse with disarray and thickening of the argyrophilic interstitial fibers, followed by scarring. The functional data showed an increased passive myocardial stiffness in the RHT4 group. We conclude that renovascular hypertension induces myocyte and arteriole necrosis. Reparative fibrosis occurred as a consequence of the inflammatory response to necrosis. The mechanical behavior of the isolated papillary muscle was normal, except for an early increased myocardial passive stiffness.
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PMID:Myocyte necrosis is the basis for fibrosis in renovascular hypertensive rats. 945 75

Vascular nephropathies are a steadily increasing cause of end-stage renal failure. Arterionephrosclerosis and arteriolonephrosclerosis are common features in the hypertensive patient. This is especially true for blacks of African descent, in whom hypertension and nephrovasculopathies are a major cause of renal insufficiency. That primary hypertension leads to renal vascular lesions, glomerular obsolescence and interstitial fibrosis has long been established. It should not, however, obscure the fact that renal vascular lesions can be observed in animal models as well as in some humans, especially young blacks, in the absence of, or anticipating the onset of hypertension. This leads to considering the hypothesis that nephroangiosclerosis might stem from a genetic defect in the renal vascular bed and that this defect is strongly associated with the hypertensive trait. Atherosclerotic renal disease is a major, potentially treatable cause of chronic renal disease is a major, potentially treatable cause of chronic renal failure, especially in whites. It leads to renal atrophy, but the ischemic kidney retains a vigorous potential for tubular cell regeneration, which pleads for early recognition and treatment. Recent data suggest that renal ischemia, be it due to renal artery stenosis or to cholesterol crystal embolism, ranks among the multiple causes of secondary focal segmental glomerulosclerosis. Irrespective of its initial mechanism, ischemia induces renal fibrosis, the pathophysiology of which is centered on increased generation of angiotensin II. Finally, renal vascular lesions are commonly observed in the course of various nephropathies, even in the absence of hypertension, and the relationship between these lesions and the unfavorable prognosis of glomerulopathies, especially primary focal-segmental glomerulosclerosis, membranous glomerulopathy and IgA glomerulonephritis, remains to be elucidated. Expanding knowledge of the spectrum of nephrovasculopathies opens perspectives for investigating, understanding and treating a major mechanism of progressive renal insufficiency.
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PMID:Ischemic renal diseases: new insights into old entities. 964 58


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