The use of Doppler ultrasound of the renal arteries for the diagnosis of vasorenal hypertension at the outpatient stage]

Ultrasonic dopplerography of the renal arteries was used to improve the differential diagnosis of arterial hypertension before hospitalization. Dopplerograms of the renal arteries of normal subjects were characterized by almost symmetrical parameters of the blood stream. In patients with vasorenal hypertension a marked asymmetry of the blood stream was seen with its reduction and qualitative changes in the dopplerogram on the side of the stenosed renal artery, that was confirmed by angiographic findings. Chronic pyelonephritis was dopplerographically characterized by hemodynamically insignificant asymmetry of the blood stream in the renal arteries with its reduction on the side of the involved kidney. In essential hypertension the type of asymmetry of blood stream parameters in the renal artery seemed similar to that in normal subjects.     

Changes in the proportion of A- and B-types of granules containing atrial and brain natriuretic peptides in atrial myocytes in vasorenal hypertension in rats

The system of cardiac natriuretic peptides (NP) is a very important factor opposing the effects of the rennin-angiotensin-aldosterone system (RAAS), sympathoadrenal system and vasopressin to reduce blood pressure. In the present study, we analyzed the release of atrial and brain natriuretic peptides in the myocytes of the right atrium in rats by the quantitative morphometric method using double immunocytochemical labeling of atrial granules comprising NP in vasorenal hypertension induced by the renal artery ligation. The decrease in the total amount of secretory granules in atrium myocytes by 18% was detected on the 30th day after the operation. The number of the A-type granules was reduced by 53%, and the number of B-type granules was increased by 64% in comparison with the intact animals. Our data indicate activation of NP secretion in vasorenal hypertension. The results suggest that high arterial pressure might be explained by reduced expression of NP receptors in this pathology.     

Morphofunctional characteristics of the intrinsic arterial vessels of the kidney in healthy subjects and in various cardiovascular diseases

The investigation has been performed in 132 kidneys of corpses of persons at various ages, 96 of them died from some cardiovascular diseases and 36--from mechanical asphyxia. Injection, macro-microscopical, histological, biometrical and variational-statistic methods have been used. The total section areas of the arterial vessels is determined, it characterizes the vascular bed capacity of the renal cortical and medullary parts. At atherosclerosis, hypertension and cardiac ischemia an essential decrease in the vascular bed capacity in the cortical part and its increase in the medullary part of the kidney is observed. An increasing diameter of the juxtamedullary glomeruli is supposed to intensify the juxtamedullary blood stream. The greatest changes in architectonics and capacity of the renal arterial bed is observed at hypertension combined with atherosclerosis, and the least--at a chronic cardiac ischemia.     

Several pathogenetic factors of experimental "indomethacin" hypertension]

The content of cyclic nucleotides (cAMP and cGMP) in the blood plasma, urine and tissues, and also morphological changes of the vascular renal bed were studied in rats with arterial hypertension induced by chronic inhibition of prostaglandin synthesis. A considerable thickening of the wall of the interlobular and arcuate arteries with marked lumen narrowing occurred mainly on account of hypertrophy and the swelling of smooth muscle cells. At the same time there was a marked increase in the cGMP concentration, a decrease of cAMP level, and a reduction of the cAMP/cGMP coefficient in the biological fluids. It is suggested that the changed cyclic nucleotides metabolism is associated with organic and functional changes of the peripheral vascular bed underlying an increase of the total vascular resistance in arterial hypertension.     

Renal artery aneurysms in children]

Renal artery aneurysms were diagnosed in 11 patients (9 boys) aged 1 to 14. The examinations were carried out for vasorenal hypertension in 4 cases, for bladder-ureter reflux, hematuria, nephroptosis in 4, ureterohydronephrosis in 2 cases, and for interstitial nephritis. Aneurysms of the major trunk of the renal artery, mostly oval-shaped, 11 x 14 to 25 x 28 mm in size, were detected in 4 patients, intrarenal aneurysms 2 x 3 to 5 x 6 mm in size in 7 cases. The share of aneurysms among uronephrologic conditions in children was found to be 1.54%, among vasorenal hypertension cases, 4.3%. Vasorenal hypertension is the main optional sign of aneurysms of the main trunk of the renal artery, whereas for intrarenal aneurysms such sign is hematuria.     

Ultrasonographic study of blood flow in the renal arteries of patients with arterial hypertension

Vascular duplex ultrasound duplex with simultaneous ECG registration was made to estimate the quantitative and time parameters of blood flow in the renal arteries with grade 1-2 arterial hypertension. There were increases in vascular resistance indices and acceleration phase index and a reduction in systolic phase index. There were correlations of the time parameters of blood flow in the renal arteries with age and lipidogram values.     

Radiologic endovascular prosthesis of the renal arteries in patients with renovascular hypertension]

A high percentage of restenoses after roentgenovascular dilatation of the renal arteries laid the basis of a search for new therapeutic methods for these patients. Experiments on implantation of nitinol spiral endoprostheses showed their ability for long-term permeability of renal arteries, not causing their thrombosis and intimal spreading, destruction of formed elements of the blood, change in plasma proteins. Morphological investigations have shown rapid formation (during 14 days) of connective tissue neointima, covered on the side of the blood flow with the true vascular endothelium (ensuring a nonadhesive surface and laminar blood flow), around the coils of an endoprosthesis. This method after its experimental development started to be used in clinical practice. The authors reported the first experience in the clinical use of this method (12 patients with vasorenal hypertension). A 15-month follow-up revealed a stable antihypertensive effect in all patients.     

Arterial hypertension and neurofibromatosis: renal artery stenosis and coarctation of abdominal aorta.

A 10-year-old girl had arterial hypertension, generalized neurofibromatosis, coarctation of the abdominal aorta and multiple stenoses at the origin of each renal artery. After resection of the stenotic areas and reimplantation of the renal arteries in the aorta, her arterial pressure decreased substantially. However, hypertension recurred and radiologic follow-up 4 1/2 years later showed distinct progression of the coarctation and renewed stenosis of all renal arteries at their origin. The stenotic areas showed eccentric intimal proliferation, frequently bulging into the lumen, with small nodular aggregates of smooth muscle cells and proliferation of fibrous tissue containing spindle-shaped nuclei in a palisading pattern. Hypertension associated with neurofibromatotic vascular disease has been described in 47 other patients in the literature. These patients have been young (mean age, 14 years) and predominantly male. In contrast to fibromuscular dysplasia, in which 95% of all stenoses are found in the distal two thirds of the renal arteries, in vascular neurofibromatosis more than 50% of the stenoses are found at the origin.     

Endothelin induces an initial increase in cardiac output associated with selective vasodilation in rats

The systemic and regional hemodynamic effects of endothelin (ET), a novel endothelial derived vasoconstrictor peptide were studied in Wistar Kyoto rats. A bolus of 1 nmol/Kg ET intravenously induced a transient 43% decrease in blood pressure associated with a 57% decrease in systemic resistance and a 30% increase in cardiac output (p less than 0.01 for all parameters). This was followed by an increase of 20% in arterial pressure and of 71% in systemic resistance and a decrease of 30% in cardiac output at 10 minutes. The initial fall in blood pressure was not abolished by pretreatment with verapamil, captopril, indomethacin, ketanserin, atropine, methylene blue or ethanol. Verapamil abolished the hypertensive phase by markedly decreasing cardiac output. ET had selective effects on the arterial tree; during the hypotensive phase it caused a transient increase in blood flow in the carotid and femoral arteries (+41% and +83% respectively, p less than 0.01) but a decrease in flow in the renal and mesenteric arteries (-53% and -44% respectively, p less than 0.05). Accordingly, there was a decrease in resistance in the carotid and femoral beds (-55% and -67% respectively, p less than 0.01) and an increase in resistance in the renal and mesenteric beds (+102%; p less than 0.01 and +23%; p = N.S. respectively). Subsequently there was an increase in resistance in all vascular beds to variable degrees. The maximal increase in resistance was in the renal bed (+156%). Thus, ET causes initially a potent systemic vasorelaxation and an increase in cardiac output later progressing to systemic vasoconstriction and a decrease in cardiac output. The initial vasodilation is selective, appearing in musculocutaneous beds but not in visceral beds.     

Morphology of myometrial and decidual arteries in normal pregnancy, in toxemia of pregnancy, and in maternal diabetes (author's transl)]

127 specimens, obtained by different methods from the myometrium and the placental bed after parturition, are investigated histologically. This material includes normal pregnancies as well as cases of maternal diabetes with and without hypertension and cases of hypertension in EPH-gestosis. The different parts of the arterial system (spiral arteries, basal arteries, radial arteries) are separately investigated. Physiologically, the pregnancy induces changes in the wall of the decidual arteries and possibly in the distal part of the radial arteries. The fibromuscular layer including the elastic fibers were destructed and replaced by fibrin and connective tissue. For this reason, in these parts of arteries it is very difficult to separate pathological from physiological changes.     

Pulmonary vascular response of the coati to chronic hypoxia.

The unusually muscular pulmonary arteries normally present in cattle and swine residing at low altitude are associated with a rapid development of severe pulmonary hypertension when those animals are moved to high altitude. Because these species lack collateral ventilation, they appear to have an increased dependence on hypoxic vasoconstriction to maintain normal ventilation-perfusion balance, which, in turn, maintains thickened arterial walls. The only other species known to lack collateral ventilation is the coati, which, similarly, has thick-walled pulmonary arteries. We tested the hypothesis that coatis will develop severe high-altitude pulmonary hypertension by exposing six of these animals (Nasua narica) to a simulated altitude of 4,900 m for 6 wk. After the exposure, pulmonary arterial pressures were hardly elevated, right ventricular hypertrophy was minimal, there was no muscularization of pulmonary arterioles, and, most surprising of all, there was a decrease in medial thickness of muscular pulmonary arteries. These unexpected results break a consistent cross-species pattern in which animals with thick muscular pulmonary arteries at low altitude develop severe pulmonary hypertension at high altitude.     

Protein kinase C activity and reactivity to phorbol ester in vascular smooth muscle from spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY)

Protein kinase C (PKC) activity in aortic and renal arterial smooth muscle from SHR (20-23 wk male; mean arterial pressure = 178 mm Hg) and WKY (age/sex matched; mean arterial pressure = 126 mm Hg) was quantitated. Activity was greatest in the particulate fractions relative to the soluble fractions in all sources. The only difference between SHR and WKY was in the soluble fraction from SHR renal arteries, which had 2 fold more activity (255 pmol/mg/min) when compared with WKY (136 pmol/mg/min). This difference was not apparently related to force modulation, since the magnitude of isometric force development in renal arteries in response to phorbol 12,13-dibutyrate was not different between SHR and WKY. The magnitude of force developed in response to phorbol 12,13-dibutyrate and PKC activity in the particulate fraction was greatest in aorta vs. renal arteries in both WKY and SHR. These results suggest that regional vascular differences in the amount of PKC activity may exist which are not apparently related to a disease state (i.e., hypertension). These differences may be related to differential sensitivity to phorbol ester-mediated contractions in isolated smooth muscle.     

Morphological aspects of age-related adaptation of the arterial vessels of the human kidneys in various cardiovascular diseases

The investigation has been performed in 190 normal kidneys and at certain cardiovascular diseases (atherosclerosis of the abdominal aorta, hypertension, chronic ischemic cardiac disease and their combination). Principally similar morphological structures are mobilized in the process of the renal arterial bed adaptation both normal and at the cardio-vascular diseases studied. Transition from certain functional changes to the organic ones in the muscular tunic and in the elastic membranes of large arteries, in correlation of afferent and deferent glomerular arterioles of all cortical layers is stated, as well as adaptive rearrangement of the microvessels and of the juxtamedullary shunt.     

Increased arterial smooth muscle Ca2+ signaling, vasoconstriction, and myogenic reactivity in Milan hypertensive rats

The Milan hypertensive strain (MHS) rats are a genetic model of hypertension with adducin gene polymorphisms linked to enhanced renal tubular Na(+) reabsorption. Recently we demonstrated that Ca(2+) signaling is augmented in freshly isolated mesenteric artery myocytes from MHS rats. This is associated with greatly enhanced expression of Na(+)/Ca(2+) exchanger-1 (NCX1), C-type transient receptor potential (TRPC6) protein, and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2) compared with arteries from Milan normotensive strain (MNS) rats. Here, we test the hypothesis that the enhanced Ca(2+) signaling in MHS arterial smooth muscle is directly reflected in augmented vasoconstriction [myogenic and phenylephrine (PE)-evoked responses] in isolated mesenteric small arteries. Systolic blood pressure was higher in MHS (145 ± 1 mmHg) than in MNS (112 ± 1 mmHg; P < 0.001; n = 16 each) rats. Pressurized mesenteric resistance arteries from MHS rats had significantly augmented myogenic tone and reactivity and enhanced constriction to low-dose (1-100 nM) PE. Isolated MHS arterial myocytes exhibited approximately twofold increased peak Ca(2+) signals in response to 5 μM PE or ATP in the absence and presence of extracellular Ca(2+). These augmented responses are consistent with increased vasoconstrictor-evoked sarcoplasmic reticulum (SR) Ca(2+) release and increased Ca(2+) entry, respectively. The increased SR Ca(2+) release correlates with a doubling of inositol 1,4,5-trisphosphate receptor type 1 and tripling of SERCA2 expression. Pressurized MHS arteries also exhibited a ～70% increase in 100 nM ouabain-induced vasoconstriction compared with MNS arteries. These functional alterations reveal that, in a genetic model of hypertension linked to renal dysfunction, multiple mechanisms within the arterial myocytes contribute to enhanced Ca(2+) signaling and myogenic and vasoconstrictor-induced arterial constriction. MHS rats have elevated plasma levels of endogenous ouabain, which may initiate the protein upregulation and enhanced Ca(2+) signaling. These molecular and functional changes provide a mechanism for the increased peripheral vascular resistance (whole body autoregulation) that underlies the sustained hypertension.     

Diagnostic possibilities of contrast magnetic resonance tomography

The practice of examinations of more than 400 patients in the diagnostic center of CRIRR showed a high diagnostic efficiency of contrast MRA, especially in stenoses, occlusions, pathologic bends of the brachiocephalic vessels; aneurysms and stenoses of the abdominal and thoracic aorta, stenoses and occlusions of visceral branches of the abdominal aorta, iliac arteries including condition of vessels after surgical correction. Valuable facts have been obtained in vasorenal hypertension caused by stenoses, occlusions, extravasal compressions, additional arteries, and in the portal system (thrombosis of the main trunk and branches of the portal vein, signs of portal hypertension).     

Localization of the sites of pulmonary vasomotion by use of arterial and venous occlusion

In this study, we present a new approach for using the pressure vs. time data obtained after various vascular occlusion maneuvers in pump-perfused lungs to gain insight into the longitudinal distribution of vascular resistance with respect to vascular compliance. Occlusion data were obtained from isolated dog lung lobes under normal control conditions, during hypoxia, and during histamine or serotonin infusion. The data used in the analysis include the slope of the arterial pressure curve and the zero time intercept of the extrapolated venous pressure curve after venous occlusion, the equilibrium pressure after simultaneous occlusion of both the arterial inflow and venous outflow, and the area bounded by equilibrium pressure and the arterial pressure curve after arterial occlusion. We analyzed these data by use of a compartmental model in which the vascular bed is represented by three parallel compliances separated by two series resistances, and each of the three compliances and the two resistances can be identified. To interpret the model parameters, we view the large arteries and veins as mainly compliance vessels and the small arteries and veins as mainly resistance vessels. The capillary bed is viewed as having a high compliance, and any capillary resistance is included in the two series resistances. With this view in mind, the results are consistent with the major response to serotonin infusion being constriction of large and small arteries (a decrease in arterial compliance and an increase in arterial resistance), the major response to histamine infusion being constriction of small and large veins (an increase in venous resistance and a decrease in venous compliance), and the major response to hypoxia being constriction of the small arteries (an increase in arterial resistance). The results suggest that this approach may have utility for evaluation of the sites of action of pulmonary vasomotor stimuli.     

Morphofunctional characteristics of cadmium-induced arterial hypertension

Chronic (12 weeks) peroral administration of cadmium chloride to albino rats in a dose of 2.5 mg/100 g body weight results in arterial hypertension characterized by the increase in systolic blood pressure up to 148 +/- 1.8 mm Hg (vs. 115.4 +/- 1.5 mm Hg in the control animals); the increase in vascular resistance, left ventricular cardiomyocyte hypertrophy, as well as by hypertrophy of arterial walls, the decrease in the ventricular index, the activation of synthesizing function of atrial endocrine cardiomyocytes; enhanced secretion of ANP; a more than two-fold increase in plasma myoglobin concentration, as well as by the development of cadmium-induced nephropathy. In the rehabilitation period (9 weeks) a relatively quick fall in the blood pressure is observed, as well as morphological features of myocardial and renal function recovery, suggesting the nonpersistent nature of cadmium-induced hypertension.     

Apport de la scintigraphie rénale avec test au captopril dans l’exploration de l’hypertension artérielle rénovasculaire : à propos d’un cas

IntroductionDynamic renal scintigraphy with ^99mTc-DTPA and captopril test is a non-invasive functional method for the diagnosis of renovascular hypertension. It allows differentiating between hypertension induced by renal arterial stenosis from primary arterial hypertension with an incidental stenosis.Case reportA 14-year-old girl, without previous medical history, developed a severe arterial hypertension with cephalgias and ears buzzing. Auscultation revealed a murmur in the left lumbar pit. Renal angiography objectified a stenosis of the infrarenal aorta due to a circumferential parietal thickening associated to renal arteries stenosis more marked in the left side. Dynamic renal scintigraphy after administration of captopril highlighted a marked collapse of the rate of tracer uptake exceeding 40% on the left side with an increase in the time of collecting on the right side testifying a frankly positive test prevailing on the left. A transluminal angioplasty of the left renal artery and a revascularisation surgery on the right side were carried out. The evolution was marked by an improvement of blood pressure figures.DiscussionDynamic renal scintigraphy using ^99mTc-DTPA with captopril test constitutes a non-invasive process with a low dosimetry for the patients. Its principal goal is to affirm the role of renovascular stenosis in the origin of arterial hypertension and to determine which hypertensive patients with renal arterial stenosis can be treated successfully by surgical or endoscopic revascularisation of the kidney.     

Chemical activation of thin-fiber phrenic afferents. 2. Cardiovascular responses

To assess the effects of groups III and IV (thin-fiber) phrenic afferents on arterial pressure, heart rate, and distribution of cardiac output, we injected capsaicin into phrenic arteries of in situ isolated and innervated left diaphragms of dogs anesthetized with chloralose, vagotomized, and mechanically ventilated. Blood flow in the ascending aorta, common carotid, renal, superior mesenteric, and femoral arteries was measured by electromagnetic and Doppler flow probes. Injection of 1 mg capsaicin into the left phrenic artery produced congruent to 15% increase in mean arterial pressure and congruent to 7% increase in heart rate with no change in aortic flow. Phrenic arterial flow decreased by 64%, renal arterial flow by 16%, and superior mesenteric arterial flow by 10%, whereas carotid flow increased by 13% and flow to the right gastrocnemius muscle did not change. Mean arterial pressure, heart rate, and blood flow distribution (with the exception of the decline in phrenic blood flow) returned to baseline within 60 s of the injection. Injection of 1.5 mg capsaicin into the right isolated and innervated gastrocnemius produced congruent to 35% increase in mean arterial pressure, 17% rise in heart rate, and no change in aortic blood flow. Phrenic and carotid arterial flow rose by 240 and 41%, respectively, whereas renal and superior mesenteric flow declined by 50 and 20%, respectively. In conclusion, thin-fiber phrenic afferents have an excitatory effect on arterial pressure and heart rate. They redistribute blood flow away from the renal and intestinal vascular beds and toward the carotid vascular bed. On the other hand, the cardiovascular reflex from thin-fiber phrenic afferents seems less potent than that from limb muscle afferents.     

Wave Transmission through an Assembly of Randomly Branching Elastic Tubes

Calculations are presented of the transmission of oscillations through an assembly of randomly branching elastic tubes, as a model of not only the major arteries, but also a peripheral vascular bed. It appears that the viscosity of the arterial wall must be the major source of attenuation in the larger arteries, while the viscosity of the blood plays a significant role only in the smaller vessels. In all situations, variations of cross-sectional area have a considerable effect on wave transmission, causing a general decrease in amplitude and an accentuation of reflection from the terminations. The effects of variation in cross-sectional area are sufficiently great to indicate that they should be included in future models of the arterial system. Finally, it is argued that because of the presence of random branching and elastic nonuniformity, the determination of the reflection coefficient for a system such as the arterial tree may be quite misleading.