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

Fibromuscular dysplasia of renal arteries was the cause of hypertension in four consecutive children with renal artery stenosis. Two were asymptomatic, the third had had hypertension for seven years but had not been treated, and the fourth, a 9-month-old infant, presented with cardiac failure. Heart enlargement and left ventricular hypertrophy were present in all. Rapid sequence urograms demonstrated a smaller kidney and delayed appearance and disappearance of the contrast medium on the affected side in all. Angiograms showed left RAS in all. Peripheral plasma renin activity was elevated in only three of the four patients. Antihypertensive and diuretic drugs were not very effective therapeutically. Ischemia of the ipsilateral kidney probably prevented normal growth and led to shrinkage of the kidney in one patient. Following nephrectomy the BP has remained normal without any therapy for 24 to 64 months. With normalization of BP, accelerated growth ensued, the cardiomegaly regressed and the hypertensive retinopathy resolved. These patients demonstrate that: (1) FMD is an important cause of RAS. (2) the well-known radiologic feature of FMD, the beaded appearance, is usually not seen in children. (3) control of BP leads to normalization of linear growth, usually impaired in severe hypertension, and (4) target organ complications such as cardiomegaly, LVH, and hypertensive retinopathy are reversible in one to 10 months.
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PMID:Fibromuscular dysplasia of renal arteries: an important cause of renovascular hypertension in children. 15 54

In the present study the effect of surgery on blood pressure was investigated in 35 patients with renovascular hypertension: 17 patients with fibromuscular hyperplasia (FMD) and 18 with atherosclerosis (ASS) of the renal artery. Patients with FMD were younger (31,8 years), showed a shorter duration of hypertension (1.8 years) and were prevalently female (82%), whereas patients with ASS were markedly older (48.2 years), showed a longer duration of hypertension (2.6 years) and were most often male (78%). In both groups of patients the intravenous urogram was positive in a comparable high percentage (FMD=64%, ASS=61%). Following surgical intervention 47%(n=8) of the 17 patients with FMD were cured, 47% (n=8) were improved and only 6% (n=1) showed insufficient reduction of blood pressure values. In ASS the respective values were 28, 55 and 17%. Consequently a good effect of surgery (cured and improved) was observed in 88.5% of all patients. Patients with ASS who failed to respond to surgery (n=3) showed a remarkable long duration of hypertension (7.0 plus or minus 1.4 years). Plasma renin activity (PRA) was determined preoperatively in both renal veins in all 35 patients. From these values the PRA-ratio (PRA affected/unaffected side) was calculated. In 27 patients PRA determinations were repeated following (15 and 30 min) intravenous injection of 40 mg furosemide. PRA-ratios of larger than or equal to 1.5 were considered to be significant. In 31 patients with unilateral renovascular hypertension PRA-ratios were correlated to the postoperative blood pressure reduction. No significant differences in mean PRA-ratios were observed between cured and improved patients. Furthermore, for the total group of 31 patients no significant correlations were obtained between PRA-ratios and postoperative blood pressure reduction. Our results do not support the widespread opinion that PRA determinations in both renal veins are useful to predict the effect of surgery in patients with unilateral renovascular disease. Therefore, from our experience this method should not be recommended as obligatory in the diagnostic work-up of renovascular hypertension.
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PMID:[Renovascular hypertension. Prognostic value of renal venous renin determinations (author's transl)]. 50 54

The gain in the diagnostic power of the routine preoperative bilateral renal vein renin investigation by the inclusion of an acute stimulation of renin release was studied in 25 hypertensive patients with fibromuscular (FMD) and 44 with arteriosclerotic (AS) renovascular disease. Nine FMD and 17 AS patients had renal vein renin ratios greater than or equal to 1.50 under unstimulated conditions. Of these 26 patients, 8 in each group improved after surgical treatment. Among the 14 FMD and 24 AS patients with ratios less than 1.50, another 9 FMD and 7 AS patients improved after operation. After acute stimulation of renin release, no less than 18 FMD and 26 AS patients had a unilateral renin secretion from the diseased kidney and of these, 14 FMD and 14 AS patients were successfully treated with operation of the stenosis. Thus the stimulation was necessary for correct preoperative diagnosis in 38% of 32 successfully operated patients, and at the same time the predictive value of a negative test increased from 0.58 to 0.80. It is concluded that acute stimulation of renin release greatly improves the diagnostic power of the renal vein renin investigation in renovascular hypertension.
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PMID:Preoperative diagnosis of renovascular hypertension. The use of acute stimulation of renin secretion. 637 75

Clinical and angiographic characteristics of renovascular hypertension were studied in 95 patients. The patients were divided into 3 groups: 55 cases with aortic arteritis (group AA), 27 with fibromuscular dysplasia (group FMD) and 9 with atherosclerosis (group AS). The patients in group AS were significantly older in age and had longer history of hypertension. Abdominal bruit was heard significantly more often in group AA and serum potassium was significantly lower in group FMD. Angiographic data showed that in group AA lesions in thoracic aorta and abdominal aorta was found in 81.4% and those involving both renal arteries in 52.5%. In group FMD, 82.5% of patients had lesion in renal artery on one side and none had lesion in thoracic and abdominal aorta. In group AS, lesions were found mainly in thoracic and abdominal aorta, accounting for 77.7% and lesions in renal arteries were mainly unilateral. In group AA, lesions were found in 90 renal arteries altogether. Among them, 58.9% was in the proximal part of the renal artery; the lesion was either localized stenosis (67.8%) or obstruction (17.7%). In group FMD, lesions were found in 33 renal arteries altogether. Among them, 48.5% was in the middle or distal part of the renal artery and 27.3% resembled string of beads. In group AS, a total of 10 renal arteries were involved with 4 (40%) of ostial stenosis and 4 (40%) total obstruction.
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PMID:[Clinical and angiographic characteristics of renovascular hypertension]. 873 48

Flow (shear stress)-mediated dilation (FMD) plays a key role in the local control of vascular diameter and blood flow supply. Although vasodilator treatments improve FMD in diverse models of hypertension, FMD may also change in situations where systemic blood pressure is not affected. In pathological situations such as ischemia, local blood flow and vascular density are increased by vasodilators not affecting systemic blood pressure. As the mechanisms involved remain obscure, we studied FMD in resistance arteries from mice treated chronically (1 month) with hydralazine (200 mg/L in drinking water). Blood flow in mesenteric arteries of mice treated with hydralazine was significantly increased (130 +/- 15 to 169 +/- 27 microl/min, n = 10/group), whereas mean arterial blood pressure was not affected (79 +/- 5 vs 82 +/- 3 mm Hg in controls). Mesenteric resistance arteries (90 microm internal diameter, 75 mm Hg) were isolated and mounted in vitro in an arteriograph. Pressure (myogenic tone)-, phenylephrine-, and KCl-induced contractions, as well as acetylcholine- and sodium nitroprusside-induced dilations, were unaffected by hydralazine. Flow-mediated dilation in arteries from hydralazine-treated mice was significantly increased, especially for low flow values (up to sevenfold). L-NAME-sensitive and indomethacin-sensitive FMD were both increased by hydralazine. Passive arterial diameter increased and arterial wall thickness decreased after chronic hydralazine. This is the first functional evidence that flow (shear stress)-mediated dilation in resistance arteries is improved by a chronic treatment with a nonselective vasodilator. This arteriolar adaptation to a chronic increase in blood flow might be of importance in the pathophysiology of ischemic diseases.
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PMID:Chronic hydralazine improves flow (shear stress)-induced endothelium-dependent dilation in mouse mesenteric resistance arteries in vitro. 1207 39

Obesity is a cardiovascular risk factor in adults. Poorly is known about effect of obesity on cardiovascular system in children. Mechanical properties of a great elastic trunk, the common carotid artery (CCA) and endothelium function of the brachial artery were studied in 130 obese children (age: 12 +/- 3 years, body mass index (BMI): 29 +/- 5.5 kg/m2, without hypertension (115 +/- 19/58 +/- 8 mmHg). These patients had a vascular high resolution echographical analysis. Cross sectional compliance (CSC), cross sectional distensibility (CSD) and incremental elastic modulus (Einc) were analysed at the CCA site. The brachial artery dilation was measured after hyperthemia (flow mediated dilation, FMD), an endothelium dependent function and after sublingually glyceryl trinitrate (GTNMD), an independent endothelium function. Fat mass composition and distribution were assessed by dual-energy X-ray absorptiometry in 70 patients. In 50 obese patients an oral glucose tolerance test was done to determine insulin resistance. The obese children had significantly lower CSC and CSD than the healthy controls (respectively 0.12 +/- 0.04 vs 0.14 +/- 0.05 mm2.mmHg-1; p < 0.05 and 0.5 +/- 0.2 vs 0.8 +/- 0.4 mmHg(-1).10(-2); p < 0.001). Obese children had higher value than the controls for Einc (2.4 +/- 0.4 vs 1 +/- 0.24 mmHg.10(3); p < 0.001) that correlated poorly with fasting insulin concentrations (r = 0.34; p < 0.06) and BMI (r = 0.34; p < 0.01). FMD was significantly lower in obese children than in controls (6 +/- 3 vs 8 +/- 4%, p < 0.01) without modification of GTNMD (17 +/- 6 vs 18 +/- 7%, NS). These two parameters were respectively correlated with the android fat distribution (r = 0.36; p < 0.01; r = 0.49; p < 0.001). The CCA stiffness of obese children is linked to the amount of the overweight and to insulin resistance. The android fat distribution is related to endothelium dysfunction.
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PMID:[Arterial rigidity and endothelial dysfunction in obese children]. 1236 70

Insulin resistance is a risk factor for atherosclerosis and is associated with hyperinsulinemia, abnormal lipid profile, and hypertension. Whether hyperinsulinemia affects vascular function independent of insulin resistance or other metabolic risk factors is unknown. This investigation aimed to assess the effects of hyperinsulinemia on endothelial function in subjects with a spectrum of insulin sensitivity and lipid profile. Endothelium-dependent (flow-mediated dilation, FMD) and -independent (nitroglycerin) responses of the brachial artery were studied by high-resolution ultrasound before and during hyperinsulinemia (euglycemic clamp) in 25 normoglycemic, normotensive subjects. Participants were divided into an insulin-sensitive and an insulin-resistant subgroup based on their sensitivity index values, with a cutoff of 8, and into a normal-cholesterol and a high-cholesterol subgroup based on their total cholesterol levels, with a cutoff of 5.2 mmol/l (200 mg/dl). In the whole population, FMD was lower during hyperinsulinemia compared with baseline (2.3 +/- 0.6% vs. 6 +/- 0.6%; P < 0.001). Resting FMD was lower in the insulin-resistant subgroup compared with the insulin-sensitive subgroup (4.2 +/- 0.9% vs. 7.4 +/- 0.8%; P = 0.014) and in the high-cholesterol subjects compared with the normal-cholesterol subjects (4.4 +/- 0.7% vs. 8 +/- 0.7%; P = 0.002). Hyperinsulinemia decreased FMD in both the insulin-sensitive (from 7.4 +/- 0.8% to 3.6 +/- 0.4%; P < 0.001) and insulin-resistant (from 4.2% to 1.22%; P = 0.012) subgroups and in both the normal-cholesterol (from 8 +/- 0.7% to 3.9 +/- 0.4%; P < 0.001) and high-cholesterol (from 4.4 +/- 0.7% to 1.1 +/- 0.8%; P = 0.01) participants. Acute hyperinsulinemia impairs conduit vessel endothelial function independent of insulin sensitivity and lipid profile. Insulin may trigger endothelial dysfunction and promote atherosclerosis.
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PMID:Insulin impairs endothelium-dependent vasodilation independent of insulin sensitivity or lipid profile. 1294 32

Endothelial dysfunction is thought to be an important factor in the development of atherosclerosis. Over the past decade, a non-invasive technique has evolved to evaluate flow-mediated vasodilation ([FMD), an endothelium-dependent function, in the brachial artery. FMD decreases with increasing age and subjects with diabetes mellitus, hypercholesterolemia, smokers and hypertension have decreased FMD. There are a few concise studies reporting that FMD predicts cardiovascular events. However, the assumption that focal measurement of brachial artery FMD predicts coronary artery disease deserves further investigation.
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PMID:Is impaired flow-mediated dilatation of the brachial artery a cardiovascular risk factor? 1532 Aug 37

This study retrospectively reviewed the technical and clinical results of percutaneous transluminal renal artery angioplasty (PTRA) for non-atheromatous renal artery stenosis (RAS) in a Tertiary Renal Referral Centre. Forty-three patients (including 9 children) underwent 49 PTRA procedures for stenoses of 63 arteries over the period 1984-2001 (14 patients had bilateral stenosis treated during one procedure. There were 29 females and 14 males (age range 1-72 years, median 37 years). The etiology of the RAS was classical beaded FMD (medial fibroplasia) in 24, atypical or "variant FMD" with a more focal stenosis (intimal fibroplasia) in 11, neurofibromatosis type 1 (NF) in 7 and Takayasu's Arteritis in 1. Five of the NF patients had angioplasty for stenoses following vascular repair procedures. A technically good result was obtained in 34/34 arteries with "classical" RAS, 9/13 atypical arteries, 11/15 arteries of NF patients and in the one Takayasu's case. Clinical follow-up for a mean of 16 months revealed a cure rate of hypertension in classical FMD of 35% with improvement in a further 55%. In the atypical FMD cases, follow-up was obtained on 6 patients with 2 cures and the other 4 demonstrating benefit. There was a better chance of cure in younger patients. In native artery PTRA in children with NF, only 1 out of 3 patients was 'cured' post-PTRA, and 2 out of 3 failed. However, in postsurgical stenoses in NF patients 1 out of 4 patients was 'cured' and 3 out of 4 improved. In conclusion, classical FMD responds well to PTRA with better results in younger patients. Atypical FMD, especially in children and when associated with NF, is less predictable. Stenoses consequent to revascularization surgery respond well to PTRA.
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PMID:Renal angioplasty in non-atheromatous renal artery stenosis: technical results and clinical outcome in 43 patients. 1538 45

Impaired endothelium-dependent vasomotion is a diffuse disease process resulting in abnormal regulation of blood vessel tone and loss of several atheroprotective effects of the normal endothelium. The aim of the present study was to investigate the effects of aging and hypertension on endothelial function. Sixty-six geriatric subjects with ages over 60 (48 hypertensive and 18 healthy) and 40 middle-aged subjects (16 hypertensive and 24 healthy) were included in the study. Systemic vascular endothelial function was evaluated through measuring brachial arterial vasodilation, a physiologic answer to reactive hyperemia occured with increased blood flow in the vessel after transient ischemia (flow-mediated dilation, FMD%), and with carotid artery intima-media thickness (IMT) measurement, using high-resolution ultrasonography. Endothelial independent vasodilation was also measured after administration of sublingual isosorbide dinitrate (isosorbide dinitrate mediated dilation, IDNMD%). FMD% was significantly decreased in elderly and/or hypertensive (HT) patients (geriatric HT: 9.5 +/- 4.7%, geriatric non-HT: 12.7 +/- 5.5%, middle-aged HT: 12.9 +/- 4.3% and middle-aged non-HT: 18.9 +/- 8.1%) (geriatric HT versus geriatric non-HT (P = 0.02), geriatric HT versus middle-aged HT (P = 0.01), geriatric non-HT versus middle-aged non-HT (P = 0.008)). Both FMD% and IDNMD% were inversely correlated with age, baseline vessel diameter and carotid artery intima-media thickness. FMD% was also inversely correlated with diastolic blood pressure. No correlation was found between FMD% and systolic blood pressure, serum cholesterol and triglyceride levels. Endothelium dependent (EDD) and independent dilatation of large arteries decreased with aging even in the healthy elderly, and FMD further declined in HT elderly patients, indicating that age and hypertension independently impair endothelial function. Positive correlations with age and hypertension, and significant inverse correlation with FMD, makes carotid artery IMT a possible indicator of endothelial function.
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PMID:Non-invasive evaluation of endothelial function in hypertensive elderly patients. 1553 Oct 24


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