Rationale and study design for one-stop assessment of renal artery stenosis and renal microvascular perfusion with contrast-enhanced ultrasound for patients with suspected renovascular hypertension.

BACKGROUND: Renal artery stenosis (RAS) is always associated with abnormalities in renal microvascular perfusion (RMP). However, few imaging methods can simultaneously evaluate the degree of luminal stenosis and RMP. Thus, this study will aim to evaluate the feasibility of using contrast-enhanced ultrasound (CEUS) for assessing both RAS and RMP to achieve a one-stop assessment of patients with suspected renovascular hypertension. METHODS: This will be a single-center diagnostic study with a sample size of 440. Patients with chronic kidney disease (CKD) and suspected of having resistant hypertension will be eligible. Patients with Stages 1-3 CKD will undergo CEUS and computed tomography (CT) angiography (CTA). Values obtained by CEUS and CTA for diagnosing low-grade (lumen reduced by <60%) and high-grade (lumen reduced by ≥60%) RAS will be compared. Moreover, all patients will also undergo radionuclide imaging. The diagnostic value for RAS will be assessed by the receiver operating characteristic curve, including the accuracy, sensitivity, specificity, positive predictive values, negative predictive values, and area under the ROC. Pearson correlation analysis will be performed to assess the association between CEUS findings for RMP and glomerular filtration rate measured by a radionuclide imaging method. CONCLUSION: The data gathered from this study will be used to evaluate the feasibility of expanding clinical applications of CEUS for evaluation of patients with suspected renovascular hypertension. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800016252; https://www.chictr.org.cn.

Duplex scan and histologic assessment of acute renal injury in a kidney-kidney crosstalk swine experimental model.

OBJECTIVE: The objective of this study was to identify the effect of two left renal vasculature occlusion strategies on the duplex ultrasound-assessed rheology and histology of the contralateral kidney. METHODS: Pigs were randomly assigned to one of two groups: left renal artery-only clamping (A group, n = 8) or left renal artery and vein clamping (AV group, n = 9). Bilateral renal parenchymal biopsy specimens were taken every 10 minutes for 90 minutes. Duplex ultrasound resistive index (RI) and pulsatility index (PI) were measured. Mixed models with normal distribution and first-order autoregressive correlation structure and generalized estimating equation models were used. Results are presented as adjusted means with standard errors, estimated proportions with standard errors, and line plots with 95% confidence intervals. RESULTS: RI and PI increased in the nonischemic kidney. In A group animals, RI values increased significantly (P < .01) after 30 minutes of ischemia and PI increased significantly (P < .04) from 30 to 60 minutes of ischemia. The number of histologic abnormalities was higher in A group than in AV group biopsy specimens. The percentage of lesions increased significantly after 10 minutes in A group nonischemic kidneys (P < .02) and between 50 and 80 minutes in AV group nonischemic kidneys (P < .01). CONCLUSIONS: Nonischemic kidneys were acutely affected by contralateral ischemia. Their function was more adversely affected by unilateral renal artery occlusion with preserved renal vein patency (A group).

Pulmonary vein isolation with concomitant renal artery denervation is associated with reduction in both arterial blood pressure and atrial fibrillation burden: Data from implantable cardiac monitor.

BACKGROUND: Renal artery denervation (RDN) has provided incremental atrial fibrillation (AF) suppression after pulmonary vein isolation (PVI) in patients with AF in the setting of drug-resistant hypertension. OBJECTIVE: To assess the relationship between changes of mean blood pressure (BP) and AF recurrences/AF burden after PVI combined with RDN. METHODS: All patients from two randomized studies with symptomatic paroxysmal AF and/or persistent AF and resistant hypertension who underwent PVI-only (n=37) or PVI with RDN (n=39), and implantable cardiac monitor (ICM) implantation were eligible for this study. Mixed-effects linear models were used to investigate the effect of RDN on mean BP and mean AF burden and associations between the two during the 12-month follow-up. RESULTS: Concomitant RDN was associated with a significant reduction in both mean AF burden (2.43 [95% CI: 1.76-3.09] % vs 6.95 [95% CI: 5.44-8.45] %) and mean BP (104 [95% CI: 103-106] mm Hg vs 112 [95% CI: 110-113] mm Hg). Decrease in mean BP was positively correlated with decline in mean AF burden: reduction of 5-10 mm Hg was accompanied by a 7.0% decreased mean AF burden, with greater reduction (up to 20 mm Hg) associated with on average 17.7% lower mean AF burden. CONCLUSIONS: Renal artery denervation when added to PVI decreases AF recurrences, AF burden, and mean BP. Reduction in mean BP is associated with both AF burden and recurrences. Further large-scale studies are needed to define the mechanistic pathway(s) of the antiarrhythmic effects of RDN.

Longitudinal Assessment of Renal Perfusion and Oxygenation in Transplant Donor-Recipient Pairs Using Arterial Spin Labeling and Blood Oxygen Level-Dependent Magnetic Resonance Imaging.

OBJECTIVES: The aims of this study were to assess renal function in kidney transplant recipients and their respective donors over 2 years using arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and to prospectively evaluate the effect of losartan on functional MRI measures in recipients. MATERIALS AND METHODS: The study included 15 matched pairs of renal transplant donors and recipients. Arterial spin labeling and BOLD MRI of the kidneys were performed on donors before transplant surgery (baseline) and on both donors and recipients at 3 months, 1 year, and 2 years after transplant. After 3 months, 7 of the 15 recipients were prescribed 25 to 50 mg/d losartan for the remainder of the study. A linear mixed-effects model was used to evaluate perfusion, R2*, estimated glomerular filtration rate, and fractional excretion of sodium for changes across time or associated with losartan treatment. RESULTS: In donors, cortical perfusion in the remaining kidney decreased by 50 ± 19 mL/min per 100 g (11.8%) between baseline and 2 years (P < 0.05), while cortical R2* declined modestly by 0.7 ± 0.3 s-1 (5.6%; P < 0.05). In transplanted kidneys, cortical perfusion decreased markedly by 141 ± 21 mL/min per 100 g (34.2%) between baseline and 2 years (P < 0.001), while medullary R2* declined by 1.5 ± 0.8 s-1 (8.3%; P = 0.06). Single-kidney estimated glomerular filtration rate increased between baseline and 2 years by 17.7 ± 2.7 mL/min per 1.73 m (40.3%; P < 0.0001) in donors and to 14.6 ± 4.3 mL/min per 1.73 m (33.3%; P < 0.01) in recipients. Cortical perfusion at 1 and 2 years in recipients receiving 25 to 50 mg/d losartan was 62 ± 24 mL/min per 100 g higher than recipients not receiving the drug (P < 0.05). No significant effects of losartan were observed for any other markers of renal function. CONCLUSIONS: The results suggest an important role for noninvasive functional monitoring with ASL and BOLD MRI in kidney transplant recipients and donors, and they indicate a potentially beneficial effect of losartan in recipients.

Renal artery stenting may not be appropriate for patients with atherosclerotic renal artery stenosis.

INTRODUCTION: This study compared aortorenal bypass to renal artery stenting to determine the most efficacious and financially sound method for treating patients with atherosclerotic renal artery stenosis (RAS). METHODS: A decision analysis using direct and indirect costs, and value of statistical life (VSL) was completed. Direct costs were obtained using the Nationwide Inpatient Sample (NIS), indirect costs from the National Institute of Diabetes and Digestive and Kidney Diseases, and VSL from the Department of Transportation. A variance-based sensitivity analysis was completed to assess the accuracy of the decision analysis. RESULTS: Aortorenal bypass has a 95% five-year patency, a 98% 30-day survival, a 26% rate of overall complications, and a 70% five-year dialysis-free survival. Renal artery stenting has a 56% five-year patency, a 99% 30-day survival, a 40% rate of complications, and a 65% five-year dialysis-free survival. Renal artery stenting has an overall cost of $305,370 and aortorenal bypass has an overall cost of $103,453 per patient. After accounting for VSL, renal artery stenting has a negative value of -$182,270 and aortorenal bypass has a value of $415,881. CONCLUSIONS: Lower five-year patency and higher rate of complications from renal artery stenting that ultimately lead to significantly lower five-year dialysis-free survival.

Assessment of abdominal branch vessel patency after bare-metal stenting of the thoracoabdominal aorta in a human ex vivo model of acute type B aortic dissection.

OBJECTIVE: The purpose of this study was to assess the efficiency of bare-metal stenting of the thoracoabdominal aorta in a human ex vivo model of acute type B aortic dissection and the impact of this approach on the patency of the visceral and renal arteries. METHODS: Fifteen human cadaveric aortas were harvested. Type B aortic dissections were surgically initiated 2 cm below the left subclavian artery. Aortas were thereafter connected to a bench top pulsatile flow to induce propagation of the dissection. A 5-mm 30° lens (Richard Wolf, Vernon Hills, Ill) was introduced successively into the false lumen and the true lumen to monitor the propagation of the dissection. Bare-metal stents were deployed into the true lumen from the primary entry tear to the infrarenal aorta. Measurement of systolic pressure was taken within the abdominal branch vessels before and after stenting. A pressure gradient drop of 15 mm Hg or more after bare-metal stenting was considered hemodynamically relevant. RESULTS: Dissection was propagated at least to the renal aorta in 11 cases (73%) and to the infrarenal aorta in 3 cases (20%). Of the 60 abdominal branch vessels studied, 22 (36.7%) were supplied by the false lumen. After extensive aortic bare-metal stenting, complete reattachment of the dissection flap was observed in all cases. Regarding visceral and renal artery patency after bare-metal stenting, a significant pressure gradient drop was reported in 54.5% (n = 12) when these arteries were supplied by the false lumen, whereas those originating from the true lumen had a significantly less common pressure gradient drop (7.9% [n = 3]; P < .0001). CONCLUSIONS: Bare-metal stenting in this model of acute type B aortic dissection was effective in true lumen reexpansion but induced a high (54.5%) rate of significant pressure drop in the visceral and renal arteries when they were supplied by the false lumen.

Doppler assessment of splanchnic arterial flow in patients with liver cirrhosis: correlation with ammonia plasma levels and MELD score.

PURPOSE: To assess the clinical significance of blood flow velocity and resistance index (RI) in the visceral arteries of patients with liver cirrhosis with respect to plasma ammonia (NH3) level and liver function. METHODS: We included 80 patients with liver cirrhosis (58 men) and 20 healthy controls (11 men). Duplex Doppler ultrasonography was used to assess flow velocity and RI in the hepatic (HA), right (RRA), and left renal (LRA), and splenic (SA) (LA) artery. Plasma NH3 was measured by biochemistry. Liver function was assessed by MELD score (model of end-stage liver disease). RESULTS: HA, LRA, and SA systolic flow velocities were greater, whereas RRA diastolic velocity was lower in patients with liver cirrhosis than in controls RI was higher in LRA, RRA, SA, and HA in patients with liver cirrhosis than in controls. NH3 levels were significantly elevated in all patients with liver cirrhosis (p < 0.05) and significantly correlated with RI of RRA, LRA, and SA. CONCLUSION: We found greater renal, hepatic, and LA RI in patients with liver cirrhosis than in healthy controls. The correlation we found between elevated renal artery RI (≥0.70) and MELD score emphasizes the risk of renal dysfunction during progression of liver cirrhosis.

Assessment of the kidneys: magnetic resonance angiography, perfusion and diffusion.

Renal magnetic resonance (MR) imaging has undergone major improvements in the past several years. This review focuses on the technical basics and clinical applications of MR angiography (MRA) with the goal of enabling readers to acquire high-resolution, high quality renal artery MRA. The current role of contrast agents and their safe use in patients with renal impairment is discussed. In addition, an overview of promising techniques on the horizon for renal MR is provided. The clinical value and specific applications of renal MR are critically discussed.

Physiological assessment of renal artery stenosis: comparisons of resting with hyperemic renal pressure measurements.

OBJECTIVES: We compared resting and hyperemic pressure gradients induced by intrarenal papaverine for the assessment of renal artery stenosis (RAS). We also investigated the incidence of the QT interval prolongation and ventricular arrhythmias. BACKGROUND: In the coronary circulation, maximal hyperemia is essential in determining the significance of a stenosis. In the renal circulation, the role of maximal hyperemia for the assessment of RAS has not been established. METHODS: In 55 patients with RAS (67 RAS), resting P(d)/P(a) ratio (the ratio between distal renal pressure to the aortic pressure), renal fractional flow reserve (FFR), and resting and hyperemic systolic gradients (RSG and HSG, respectively) were measured with a pressure guidewire. In a subset of 16 patients, renal vein renin activity (RVRA) was measured. RESULTS: HSG was significantly greater than RSG (20 ± 14 mm Hg vs. 9.0 ± 13 mm Hg, respectively; P < 0.001). Renal FFR was significantly lower than baseline P(d)/P(a) ratio (0.91 ± 0.06 vs. 0.94 ± 0.06 vs. respectively; P < 0.001). RVRA increased from 50 ± 66% at rest to 122 ± 112% at hyperemia, P < 0.01. At HSG of 21 mm Hg or renal FFR of 0.90, RVRA increased markedly (120%), but RVRA increased modestly (18%) when RSG was 16 mm Hg or resting P(d)/P(a) ratio was 0.93. The corrected QT intervals at baseline vs. hyperemia were not significantly different (433 ± 26 vs. 436 ± 25 msec, respectively; P = NS); no episodes of ventricular arrhythmias were noted. CONCLUSIONS: Renin production, an index of renal ischemia, was markedly greater at hyperemia than at rest, suggesting that RAS, with either an HSG of 21 mm Hg or a renal FFR of 0.90, can be considered a hemodynamically significant stenosis. Intrarenal papaverine neither prolonged the QT interval nor induced ventricular arrhythmias and the safety of which will need to be corroborated in a large study. © 2010 Wiley-Liss, Inc.

Assessment of renal vascular resistance and blood pressure in dogs and cats with renal disease.

This study investigated the possible relationships between renal resistive index (RI) or pulsatility index (PI) and systolic blood pressure and biochemical and haematological parameters in dogs and cats with renal disease. The study included 50 dogs and 20 cats with renal disease. RI and PI were significantly higher in both dogs and cats with renal disease than in 27 healthy dogs and 10 healthy cats. In dogs, a significant negative correlation was found between RI and red blood cell count, and a positive correlation was found between PI and serum creatinine. In cats, a positive correlation was found between RI and serum urea, between PI and serum creatinine, and between PI and serum urea. No relationship could be found between either RI or PI and systolic blood pressure.

Assessment of renal artery fibromuscular dysplasia: angiography, intravascular ultrasound (with virtual histology), and pressure wire measurements.

Fibromuscular dysplasia (FMD) of the renal arteries is classically associated with secondary hypertension in younger individuals, which may be treatable and even curable by percutaneous transluminal renal angioplasty. Angiography of these renal arteries often displays "beaded" luminal abnormalities. The angiographic findings, however, may not accurately reflect the severity or precise location of the intraluminal obstruction. We present a case of an older individual with longstanding hypertension and FMD, in whom the use of a coronary pressure wire and intravascular ultrasound enabled precise localization and treatment of the hemodynamically significant stenosis. Virtual histology of FMD in the renal vasculature is also reported.

Assessment of the effect of radio contrast media on resistive index of renal artery by color doppler sonography.

Renal ischemia and direct toxic effect of contrast media are the main confounding causes of contrast-induced nephropathy (CIN). The effect of different contrast mediums on the resistance of renal artery is quite unclear. The aim of the present study was to assess the resistive index (RI) changes of renal segmental artery in color Doppler duplex sonography after injection of two different contrast mediums: iodixanol and iohexol. The RI of the renal segmental artery of 62 randomly chosen patients, with a normal baseline renal function, was calculated using color-coded Doppler sonography before and five minutes after bolus injection of two different contrast mediums. Thirty-one patients were administered 50 mL of iodixanol (Visipaque) and 31 patients were administered 50 mL of iohexol (Omnipaque) during intravenous urogram procedures. The RI results were analyzed and compared in two groups using two-tailed t-test. The mean RI of renal segmental artery increased significantly after administration of contrast media (mean +/- SD 0.61 +/- 0.046 vs 0.58 +/- 0.042; p< 0.001). The mean change of RI was 0.0387 +/- .00552 (mean +/- SE) in the setting of iohexol injection and 0.0216 +/- .00423 (mean +/- SE) five minutes after administration of iodixanol (p= 0.017). Both non-ionic iso-osmolar dimeric iodixanol and low-osmolar iohexol increase the renal artery resistance, but the changes are more dramatic with iohexol, suggesting better tolerance with iodixanol.

Clinical significance and renal haemodynamics of incidentally detected retroaortic left renal vein: assessment with venous Doppler sonography.

The purpose of this study was to determine whether renal venous pulsations are affected by compression of the left renal vein (LRV) between the aorta and spine, and also to determine the clinical significance of incidentally detected retroaortic LRV. The study population was recruited from 783 consecutive patients undergoing abdominal CT examination for various indications. 22 patients with a retroaortic LRV were prospectively enrolled in this study, and 22 patients without renal disease served as a control group. After measuring the diameters of the central and peripheral portions of the LRV on CT images, the ratio (P/C) and difference (P-C) of the diameters were calculated. Doppler sonography of the interlobar arteries and veins of the left kidney was then performed to obtain impedance indices. Urine analysis of all subjects and scrotal colour Doppler ultrasound of male patients were also performed. The retroaortic LRV diameters were significantly narrower than the pre-aortic LRV diameters (p = 0.002). The left intrarenal venous impedance indices were significantly higher in the patients with retroaortic LRV (p = 0.026) and in the subgroups with P/C>2 (p = 0.020), with P-C>4 mm (p = 0.007) and without nutcracker-like associations (p = 0.006) than in control subjects, but no significant difference was noted between the arterial resistance indices. Haematuria (n = 8), proteinuria (n = 4), varicocele (n = 3) and collaterals (n = 1) were detected in the study group but not in the control group. In conclusion, incidentally detected retroaortic LRV appears to be associated with haematuria, proteinuria, varicocele and altered venous pulsatility. Further investigations are needed to understand the role of venous Doppler ultrasound in the nutcracker phenomenon.

Assessment of renal hemodynamic effects of nesiritide in patients with heart failure using intravascular Doppler and quantitative angiography.

OBJECTIVES: We evaluated the magnitude and site of action of the nesiritide mediated renal vasodilatory effect in patients with heart failure (HF). BACKGROUND: Nesiritide, a recombinant human B-type natriuretic peptide is approved for the treatment of acute decompensated HF and has been shown to exert favorable hemodynamic, neurohormonal, and symptomatic effects. The renal effect of nesiritide in HF patients has not been well defined. METHODS: In 15 patients with acute decompensated HF, intravascular Doppler and quantitative angiography of the renal artery were used to assess the effect of nesiritide on renal artery diameter and velocity time integral as well as renal blood flow and vascular resistance. Nesiritide was administered intravenously at a standard dose of 2 microg/kg bolus followed by a continuous infusion at a rate of 0.01 microg/kg/min. Assessment of nesiritide effect was made at 15 min. RESULTS: Nesiritide infusion was associated with a significant central hemodynamic effect including a fall in mean pulmonary artery pressure (36 +/- 12 mm Hg to 31 +/- 13 mm Hg, p < 0.001), mean pulmonary capillary wedge pressure (21 +/- 2 mm Hg to 15 +/- 10 mm Hg, p < 0.001), and systemic vascular resistance (1,995 +/- 532 dynes s cm(-5) to 1,563 +/- 504 dynes s cm(-5), r < 0.001), and an increase in cardiac output from 3.9 +/- 1.2 l/min to 4.6 +/- 1.6 l/min (p = 0.001). Nesiritide was also associated with a significant vasodilatory effect on the large conductance renal arteries resulting in an increase in renal artery diameter from 6.2 +/- 0.7 mm to 6.7 +/- 0.8 mm (p < 0.001). At the same time, there was a concomitant fall in mean renal artery pressure (99 +/- 17 mm Hg to 89 +/- 13 mm Hg, p = 0.002) and renal blood flow velocity time integral (27 +/- 15 cm/beat to 23 +/- 15 cm/beat, p = 0.008) and, therefore, no significant change in renal blood flow or renal vascular resistance. CONCLUSIONS: The nesiritide effect on the renal circulation in patients with HF is complex, with a marked vasodilatory action on the large, conductance renal arteries but a concomitant fall in velocity time integral and no effect on renal vascular resistance or renal blood flow. Lack of increase in renal blood flow may be due to a fall in renal blood pressure or an intrarenal vasoconstrictive effect.

MR imaging assessment of changes in renal function with renal artery stent placement in swine.

PURPOSE: To prospectively test the hypothesis that magnetic resonance (MR) imaging can detect changes in renal function at the time of renal artery stent placement in a swine model of renal artery stenosis (RAS). MATERIALS AND METHODS: In this animal care and use committee-approved study, hemodynamically significant (>50%) RAS was surgically induced in six pigs. MR imaging was employed for assessment of the anatomic and physiologic changes induced by fluoroscopically guided stent placement. With MR imaging, we assessed changes in renal blood flow (RBF), extraction fraction (EF), and single-kidney glomerular filtration rate (skGFR) during the procedure. Arterial diameter stenosis before and after stent placement was assessed with x-ray digital subtraction angiography (DSA). Mean changes in functional and anatomic parameters were compared with the Wilcoxon matched-pairs test, with an alpha level of 0.05. RESULTS: There was no significant change in mean RBF after stent deployment (P=.44). Mean EF increased from 0.19+/-0.08 before stent placement to 0.31+/-0.17 after stent placement (P=.16). Mean skGFR measurements were 25 mL/min+/-16 before stent placement and 41 mL/min+/-28 after stent placement (P<.05). According to x-ray DSA measurements, mean stenosis measurements were 60%+/-12% before stent placement and 24%+/-16% after stent placement (P<.02). CONCLUSIONS: In swine, MR imaging can detect immediate changes in renal function after radiographically guided stent placement for unilateral RAS. This functional MR technique may have applications in the setting of hybrid MR/x-ray DSA procedure suites.

Best duplex-sonographic criteria for the assessment of renal artery stenosis--correlation with intra- arterial pressure gradient.

PURPOSE: Colour coded duplex sonography (DS) is widely used for the assessment of renal artery stenosis (RAS). Different criteria have been specified for the detection of significant RAS. The aim of our study was to compare routinely used DS criteria, both with intra-arterial pressure gradients and arteriographic degree of stenosis, and to validate different cut-off points of these DS criteria for the assessment of haemodynamically significant RAS. MATERIALS AND METHODS: We retrospectively analysed forty-nine patients (median age 67 years, 29 male) with RAS documented by duplex sonography, referred for renal arterial subtraction arteriography and intra-arterial pressure measurement (93 renal arteries). DS measurement of peak systolic velocity (PSV) in the main renal artery, the renal/aortal velocity ratio (RAR) and the side-to-side differences of the intrarenal resistive indices (DeltaRI) were correlated to intra-arterial pressure measurements and arteriographic degree of stenosis. Receiver operating characteristics (ROC) were used to determine the best cut-off value of DS criteria. RESULTS: 39 (41 %) renal arteries had normal findings or non significant stenosis < 50 %, 23 (25 %) had a diameter reduction between 50 % and 69 %, and 31 (33 %) > or = 70 %. The systolic pressure gradient showed good correlation with the arteriographic degree of RAS (r = 0.77, p < 0.001) and the PSV measured by duplex sonography (r = 0.67, p < 0.001). Mean systolic pressure gradient was 24 mmHg at 50 % stenosis and 23 mmHg at PSV of 200 cm/sec. A PSV of > or = 200 cm/sec provided a sensitivity of 92 % and specificity of 81 % for detecting RAS of > or = 50 %. Similar results were found for RAR > or = 2.5 with a sensitivity of 92 % and specificity of 79 %. These cut-off values have a negative predictive value of 100 % for excluding high-grade RAS of > or = 70 %. A DeltaRI of > or =0.05 has low sensitivity of 31 %, but a high specificity of 97 % for detecting RAS of > or = 50 %. CONCLUSION: DS measurements and the severity of arteriographic diameter reduction correlate well with systolic pressure gradients. Clinically expedient DS criteria for detecting RAS of > or = 50 % are a PSV of > or = 200 cm/sec or a RAR of > or =2.5. These criteria allow reliable exclusion of severe RAS of > or = 70 %.

Renal frame count: a quantitative angiographic assessment of renal perfusion.

Renal perfusion may be measured by a variety of noninvasive methods; however, there is no objective angiographic method to assess renal perfusion. We measured the renal frame count (RFC) in 26 patients (50 kidneys) with normal renal function and normal renal angiograms and 9 patients (15 kidneys) with renal artery fibromuscular dysplasia (FMD) and normal renal function. The mean age of the patients with normal renal arteries was 61.5 +/- 9.5 (range, 47-82 years) and the mean age of patients with FMD was 72.5 +/- 9.2 (range, 54-86 years; P = 0.005). There was no correlation between the age and RFC in both the normal renal artery group and the FMD group. The mean RFC for the normal renal arteries was 20.4 +/- 3 (95% CI = 19.5-21.2), which was significantly lower than the FMD group's mean RFC of 26.9 +/- 9.9 (95% CI = 21.4-32.4; P = 0.0001). RFC is an objective angiographic measure to quantify renal perfusion. Compared to normal renal arteries, those with FMD had significantly increased RFC consistent with decreased perfusion.

[Assessment of vasomotor endothelial function in patients with diabetes mellitus type 1 at different stages of diabetic nephropathy]. / Otsenka vazomotornoi funktsii éndoteliia u bol'nykh sakharnym diabetom tipa 1 na raznykh stadiiakh diabeticheskoi nefropatii.

AIM: To study a vasomotor endothelial function in patients with diabetes mellitus (DM) type 1 at different stages of diabetic nephropathy (DN). MATERIAL AND METHODS: Twenty six patients with DM type 1 (11 males and 15 females, mean age 25.9 +/- 4.3 years, mean history of DM 12.9 +/- 3.4 years) entered the study. They were divided into 4 groups: group 1--without renal affection, group 2--with microalbuminuria (MAU), group 3--with proteinuria (PU), group 4--with chronic renal failure (CRF). The control group consisted of 7 healthy volunteers. Endothelium-dependent vasodilation (EDVD) was studied in the test with reactive hyperemia provoked by 4-5 min occlusion of the brachial artery by pneumocollar and subsequent assessment of arterial diameter changes after decompression using high-resolution ultrasound dopplerography. RESULTS: Reactive hyperemia resulted in dilation of the artery in all the examinees. This dilation was maximal on second 30 after removal of the collar in the controls, group 2, 3 and 4 and reached 9.2 +/- 2.9, 9.63 +/- 3.62, 7.25 +/- 5.23 and 4.42 +/- 4.05%, respectively. Resting blood flow velocity was similar in all the groups and rose maximally by 95-150%. To estimate EDVD of the brachial artery more precisely, the coefficient of endothelial sensitivity to shift tension was calculated. It made up 0.084 +/- 0.04 (control group), 0.0825 +/- 0.08 (group 1), 0.138 +/- 0.07 (group 2), 0.067 +/- 0.05 (group 3) and 0.052 +/- 0.04 (group 4). CONCLUSION: At the earliest stage of DN (stage MAU), EDVD is not affected as maximal vasodilation of the brachial artery and endothelial sensitivity to shift tension do not differ from the control values. This means that the stage of MAU is reversible in early treatment, but PU and CRF are not reversible stages associated with depletion of endothelial cells and loss of sensitivity to changing hemodynamic conditions.

[Role of ultrasound dopplerography with acute captopril test in assessment of renal hemodynamics in chronic glomerulonephritis]. / Pol' ul'trazvukovoi dopplerografii s ispol'zovaniem ostroi farmakologicheskoi proby s kaptoprilom v otsenke pochechnoi gemodinamiki pri khronicheskom glomerulonefrite.

AIM: To examine blood flow in renal and intrarenal arteries and its changes in the acute pharmacological test with captopril in patients with chronic glomerulonephritis (CGN). MATERIAL AND METHODS: Renal circulation was studied in 50 patients with CGN using ultrasound dopplerography (USDG) of renal vessels on the unit GE Logiq 400 CL PRO Series. The velocity and indices of peripheral blood resistance in the major renal artery (RA) and in intrarenal arteries were estimated. In 26 patients the blood flow was studied again after intake of 50 mg captopril. RESULTS: Poor renal blood flow was registered in cortical parenchyma in 36% CGN patients (with chronic renal failure in 75%). Multifactorial regression analysis has demonstrated that only blood creatinine was independently related with slowing down of the blood flow at the level of RA and intrarenal arteries. Morphological index of activity correlated with resistance indices while a high sclerosis index correlated with blood flow slowing. Older patients had higher resistance indices. Captopril significantly accelerated blood flow and insignificantly changed indices of peripheral resistance including those in CRF patients. CONCLUSION: Poor blood flow in the cortical layer of renal parenchyma in CGN, according to USDG, occurs rather frequently and was associated with CRF and older age of the patients. Blocking of renin-angiotensin system at the level of angiotensin II formation improves renal blood flow in most of the patients.