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

Renovascular hypertension is defined as a kind of hypertension secondary to altered renal perfusion with the activation of the renin-angiotensin system. Since a large number of these patients benefits from treatment--be it medical, surgical or angioplastic--a non-invasive low-cost method allowing accurate screening was looked for. Color-Doppler was employed by many authors to evaluate renovascular hypertension, for both the early diagnosis of the condition and the evaluation of treatment results in renal artery stenoses. However, the authors agree that color-Doppler cannot play a major role in the screening of renovascular hypertension due to the various qualitative and quantitative variables not being adequately codified, to the lack of a single color-Doppler method and to the difficult comparison of the results from the different units. Nevertheless, improved results are promised by technological evolution, together with the possibility to codify color-Doppler variables more easily repeatable. B-mode units with 3.5 and 5 MHz probes were employed in the thinnest subjects. In 5-25% of cases accessory renal arteries were observed. After identifying the vessel to be studied with several spatial scans, the smallest possible sample volume (usually 3-5 mm) was positioned. The normal flowmetric range was 0.07-0.1 s: it must not exceed 0.16 s, with persistence of high diastolic flow. Some authors' criteria were followed to define either stenosis or renal artery obstruction; moreover, pulsatile flow index was considered, together with the resistive index, pulsatility index and stenosis index.
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PMID:[Color-Doppler and angioplasty in renovascular hypertension]. 833 15

Renovascular hypertension profoundly alters skeletal muscle arteriolar responses to sepsis, yet systemic hemodynamics to sepsis are not affected by hypertension. In this study, we hypothesized that microvascular responses of skeletal muscle and systemic hemodynamics are changed during high- and low-cardiac-output Escherichia coli bacteremia in normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). During high-cardiac-output bacteremia, blood pressure and heart rate increased in WKY, but blood pressure decreased in SHR. During low-cardiac-output bacteremia, blood pressure initially decreased in WKY, while in SHR, pressure dropped significantly and remained severely depressed. Heart rate increased by 50% in SHR, but only by 10-15% in WKY during low-cardiac-output bacteremia. Large A1 and A2 arterioles constricted in both WKY and SHR during both phases of bacteremia. Small A3 and A4 arterioles dilated in WKY during bacteremia, but this small arteriole dilation was blunted in SHR. However, nitroprusside, an endothelium-derived relaxing factor (EDRF)-independently acting vasodilator, caused maximal dilation of these small arterioles of SHR. We conclude that there are profound changes and differences in systemic hemodynamics during bacteremia between the normotensive and the genetically hypertensive groups, whereas despite a possibly decreased endothelium-dependent vasodilator responsiveness in small arterioles of SHR during bacteremia, overall blood flow changes in skeletal muscle were similar among the two groups.
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PMID:Systemic hemodynamic and microvascular responses in spontaneously hypertensive rats during Escherichia coli bacteremia. 834 79

Renovascular hypertension and high renin hypertension were found to be associated with an excess prevalence of carotid artery atherosclerotic lesions and to a higher risk of stroke, respectively, as compared to low-to-normal renin hypertension. Primary aldosteronism, being characterized by hypertension and a chronically suppressed plasma renin activity, should be accompanied by a low prevalence of carotid artery lesions. To verify this hypothesis we investigated prospectively, by a high resolution duplex ultrasound technique, the prevalence of extracranial carotid artery lesions in a case-controlled study of 34 (22 women and 12 men, aged 22 to 76 years) patients with no history or symptoms of cerebrovascular disease. Primary aldosteronism was diagnosed in 17 patients; 12 had a surgically confirmed unilateral aldosterone-secreting adenoma; and 5 had idiopathic hyperaldosteronism. Each primary aldosteronism patient was individually matched with a control with primary hypertension for sex, race, age, body mass index, casual blood pressure levels, duration of hypertension, smoking, diabetes mellitus, total serum cholesterol, and triglycerides. After the matching, the two groups were similar in terms of demographic features and overall cardiovascular risk profile (all P = NS). However, plasma renin activity and aldosterone levels were significantly lower and higher, respectively, in primary aldosteronism than in primary hypertensive patients. In primary aldosteronism the overall prevalence of carotid artery lesions at duplex was 59%, not significantly different from that (53%) found in primary hypertensives. Thus, at variance with renovascular hypertension, primary aldosteronism is not associated with an excess prevalence of carotid artery lesions.
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PMID:Prevalence of extracranial carotid artery lesions at duplex in primary aldosteronism. 842 67

Renovascular hypertension represents 1 to 2% of all causes of hypertension. It is important to make the diagnosis as radical treatment may be proposed. Digitised arteriography is the reference diagnostic method. Spiral angiotomography is a new diagnostic technique for the investigation of the aorta and its branches. The examination was performed with a Siemens Somatom Plus S spiral scanner. The images were acquired after intravenous injection of 140 ml of iodine contrast medium in the forearm. Three dimensional reconstruction of the renal arteries may be performed secondarily. The results of 16 examinations were compared with those of arteriography. Nine stenoses were suspected after spiral angiotomography and confirmed in 7 cases by arteriography (sensitivity 100%; specificity 77%); two adrenal abnormalities were also detected by spiral tomography. In this series, spiral angiotomography detected all cases of renal artery stenosis with good specificity. Moreover, this investigation also allowed evaluation of the adrenal glands. The simple, non-invasive and polyvalent nature of this method should, if the results are confirmed in a large series, lead to its use as the investigation of first intention for suspected secondary causes of hypertension.
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PMID:[Value of spiral computed tomography with three-dimensional reconstruction in the investigation of renal arteries. An initial clinical experience apropos of 16 cases]. 876 Jun 57

Renovascular hypertension is a syndrome for which, historically, the description of the pathophysiological model in animals preceded the clinical description in human patients. These models allow to understand the local paracrine and systemic endocrine role of the renin-angiotensin system. Whatever the method used to induce renovascular hypertension, the model goes through an initial stage of renin-angiotensin activation, which is followed sooner or later by retention of salt and water. The logical approach to the diagnosis and treatment of renovascular hypertension in man proceeds from this experimental pathophysiological description. The diagnosis establishes a relationship between the stenosis of the renal artery, the systemic arterial hypertension associated with its consequences on the target organs, particularly the kidney downstream to the stenosis (ischaemia) and the contralateral kidney exposed to hypertension, and the high levels of circulating renin and angiotensin (nephro-angiosclerosis). The diagnosis involves a systemic and separate approach to the endocrine and excretory functions of the kidney under basal conditions and after acute blockade of the renin-angiotensin system. Therapeutic indications also proceed from similar logical pathophysiological approaches.
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PMID:[Renal artery obstruction: from experimental models to logical approach to diagnosis and treatment]. 876 13

To define the clinical characteristics of renovascular hypertension (RVH) and determine the clinical usefulness of captopril stimulated peripheral renin and postcaptopril renography in blacks at risk for RVH, 79 clinically selected hypertensive blacks were evaluated. Unstimulated (U-PRA), captopril stimulated (S-PRA) peripheral renin, and postcaptopril renography (PC-RENO) were obtained. All subjects underwent conventional renal arteriography. Renal artery stenosis (RAS) was present in 14 of 79 (18%) patients. Renovascular hypertension (RVH) was found in 7 of 79 (9%) patients. S-PRA had a sensitivity and specificity of 38% and 86% respectively to detect RAS; and a sensitivity and a specificity of 17% and 85% respectively to detect RVH. PC-RENO had a sensitivity and a specificity of 64% and 58% respectively to detect RAS; and a sensitivity and a specificity of 67% and 58% respectively to detect RVH. This study suggests that RAS occurs in 18% of clinically selected hypertensive blacks. RVH was present in 9% of this population. Captopril stimulated peripheral renin and postcaptopril renography are not useful as screening tools for the diagnosis of renovascular disease in blacks. Blacks at high risk should be evaluated with angiography.
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PMID:Renovascular hypertension in blacks. 883 2

Two boys, 11 and 10 years of age, respectively, having renovascular hypertension are reported. Diagnostically, captopril test and renal scintigraphy were useful as pharmacologic probes of the renal arterial stenosis and to determine its laterality, as well for examination of the operative outcome. Both children were rendered normotensive after renal revascularization, one by renal autotransplantation and the other by aortorenal bypass procedure. Renovascular hypertension in children is also discussed.
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PMID:Surgical revascularization in children with renovascular hypertension. 887 69

We investigated the early changes in the choroidal vasculature in rats following surgically induced renovascular hypertension. Renovascular hypertension was induced in a group of 12 male Wistar rats using a modified Goldblatt procedure. The rats were divided into four groups, each being sacrificed at weekly intervals, the first group being sacrificed 1 week following the procedure. Vascular casts were prepared of the choroidal circulation using acyl resin (mercox). These were then studied using the scanning electron microscope. No abnormality of the choroidal circulation was noted for the first 2 weeks. At 3 weeks, when a rise in the average mean arterial pressure was noted, nodular lesions were seen in the choroidal arteries and choriocapillaris. These lesions were present in far greater numbers by 4 weeks. It seems likely that the nodular lesions described are microaneurysms and may contribute to the pathogenesis of the clinically described Elschnig spot.
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PMID:Early changes in the choroidal vasculature of rats occurring with experimentally induced hypertension. 887 89

Although systolic left ventricular (LV) function is normal in the elderly, aging is associated in rat papillary muscle with mechanical and sarcoplasmic reticulum Ca2+ ATPase alterations similar to those observed in the hypertrophied heart. However, alterations in the other calcium-regulating proteins implicated in contraction and relaxation are still unknown. To investigate alterations in LV function and calcium-regulating proteins, we measured hemodynamics and Na(+)-Ca2+ exchanger (NCx), ryanodine receptor (RyR2), and sarcoplasmic reticular Ca2+ ATPase (SERCA2) mRNA levels (expressed in densitometric scores normalized to that of poly(A+) mRNA) in left ventricle from 4-month-old (adult, n = 13) and 24-month-old (senescent, n = 15) rats. For ex vivo contractile function, active tension was measured during isolated heart perfusion in adult (n = 11) and senescent (n = 11) rats. For comparison of age-dependent effects of moderate hypertension on both hemodynamics and calcium proteins, renovascular hypertension was induced or a sham operation performed at 2 (n = 11 and n = 6) and 22 (n = 26 and n = 5) months of age. In senescent rats, LV systolic pressure and maximal rates of pressure development were unaltered, although active tension was depressed (4.7 +/- 0.4 versus 8.3 +/- 0.7 g/g heart weight in adults, P < .0001). SERCA2 mRNA levels were decreased in senescent left ventricle (0.98 +/- 0.05 versus 1.18 +/- 0.05 in adults, P < .01), without changes in NCx and RyR2 mRNA accumulation. Renovascular hypertension resulted in 100% mortality in aged rats; in adults, renovascular hypertension resulted, 2 months later, in an increase of LV systolic pressure (170 +/- 7 versus 145 +/- 3 mm Hg in sham-operated rats, P < .05) and in mild LV hypertrophy (+18%, P < .01) associated with a decrease in SERCA2 mRNA levels (1.02 +/- 0.03 versus 1.18 +/- 0.03 in sham-operated rats, P < .001). Contractile dysfunction in senescent isolated heart and decreased SERCA2 mRNA levels were associated with in vivo normal LV function at rest, indicating the existence of in vivo compensatory mechanisms. RyR2 and NCx gene expressions were not implicated in the observed contractile dysfunction. In aged rats, renovascular hypertension resulted in 100% mortality, probably related to elevated levels of circulating angiotensin II, whereas in adult rats, renovascular hypertension induced a mild LV hypertrophy associated with a selective alteration in SERCA2 gene expression.
Hypertension 1997 Jan
PMID:Senescent heart compared with pressure overload-induced hypertrophy. 903 74

Renovascular hypertension is a potentially curable, secondary form of hypertension. It is caused by renal ischemic disease, which remains a significant clinical problem because of the increasing incidence of atherosclerosis with aging of the overall population. The role of the reinin-angiotensin system in renovascular hypertension has been consolidated by the discovery of angiotensin II receptor subtypes, various tissue renin-angiotensin systems and the function of angiotensin II as a vascular growth factor. To date renal vein renin estimation and converting enzyme renography seem to be the most reliable investigations to demonstrate the hypertensive role of a kidney before revascularization. Percutaneous transluminal angioplasty is a successful treatment in selected forms of renal artery stenosis. Open surgery consists of either bypass procedure or renal autotransplantation with extracorporeal reconstruction of the renal vasculature in cases of aneurysms or segmental renal artery stenoses. Control of hypertension and, increasingly important, preservation of renal function can be safely and successfully achieved, on the basis of careful diagnosis and individual selection of the therapeutic procedure are performed.
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PMID:[Renovascular arterial hypertension: current aspects of physiopathology, diagnosis and treatment]. 924 50


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