Degree Of Renal Artery Stenosis Research Articles

Relationship between 24-h Ambulatory Blood Pressure Variability and Degree of Renal Artery Stenosis in Hospitalized Patients with Hypertension.

Blood pressure variability (BPV) is a critical risk factor for cardiovascular outcomes and is associated with atherosclerotic renal artery stenosis (ARAS), which is diagnosed using digital subtraction angiography (DSA). However, the relationship between the degree of renal artery stenosis (d-RAS), diagnosed using renal artery contrast-enhanced ultrasound (CEUS), and 24-hour ambulatory BPV in hospitalized patients with ARAS remains unclear. Hospitalized hypertensive patients were divided into ARAS and non-ARAS groups based RAS diagnoses using CEUS. The ARAS patients were further classified into unilateral and bilateral categories. Quantification of BPV over 24 hours, daytime, and nighttime utilized standard deviation (SD), coefficient of variation (CV), and average real variability (ARV). Percentage stenosis was used to evaluate d-RAS. Pearson's and multivariate beta regression analyses were used to assess correlations between BPV and d-RAS. We found that 24-hour systolic BPV (SBPV), presented as SD, CV, and ARV indices, was positively correlated with unilateral d-RAS (R1 = 0.460, p = 0.001; R1 = 0.509, p < 0.001; R1 = 0.677, p < 0.001, respectively). This correlation was consistent with the daytime SBPV (R1 = 0.512, p < 0.001; R1 = 0.539, p < 0.001; R1 = 0.678, p < 0.001, respectively) and daytime diastolic BPV (DBPV) (R1 = 0.379, p = 0.010; R1 = 0.397, p = 0.007; R1 = 0.319, p = 0.033, respectively). Similarly, 24-hour DBPV assessed by SD and CV also correlated positively with unilateral d-RAS (R1 = 0.347, p = 0.019; R1 = 0.340, p = 0.022, respectively), as did nighttime SBPV assessed by ARV indices (R1 = 0.415, p = 0.005). No significant correlations were found between BPV and bilateral d-RAS (p > 0.05). Multivariate beta regression analysis indicated that 24-hour SBPV (odds ratio [OR] = 1.035, 95% confidence interval [CI]: 1.054-1.607, p = 0.035) and daytime SBPV (OR = 1.033, 95% CI: 1.004-1.061, p = 0.023; both evaluated via AVR) were independent risk factors for d-RAS. SBPV is positively correlated with unilateral d-RAS at all time points. Both 24-hour and daytime SBPV (evaluated using ARV indices) were identified as independent d-RAS risk factors.

Evaluating Short-Term and Long-Term Risks Associated with Renal Artery Stenosis Position and Severity: A Hemodynamic Study.

Background: Moderate renal artery stenosis (50-70%) may lead to uncontrolled hypertension and eventually cause irreversible damage to renal function. However, the clinical criteria for interventional treatment are still ambiguous in this condition. This study investigated the impact of the position and degree of renal artery stenosis on hemodynamics near the renal artery to assess the short-term and long-term risks associated with this disease. Methods: Calculation models with different degrees of stenosis (50%, 60%, and 70%) located at different positions in the right renal artery were established based on the computed tomography angiography (CTA) of a personalized case. And computational fluid dynamics (CFD) was used to analyze hemodynamic surroundings near the renal artery. Results: As the degree of stenosis increases and the stenosis position is far away from the aorta, there is a decrease in renal perfusion. An analysis of the wall shear stress (WSS)-related parameters indicated areas near the renal artery (downstream of the stenosis and the entrance of the right renal artery) with potential long-term risks of thrombosis and inflammation. Conclusion: The position and degree of stenosis play a significant role in judging short-term risks associated with renal perfusion. Moreover, clinicians should consider not only short-term risks but also independent long-term risk factors, such as certain regions of 50% stenosis with adequate renal perfusion may necessitate prompt intervention.

The performance of duplex ultrasonography for the assessment of renal artery stenosis in Takayasu’s arteritis patients

BackgroundThis study intends to analyze the hemodynamic parameters of the renal artery in patients with Takayasu’s arteritis (TAK) to explore the diagnostic efficacy of duplex ultrasonography in assessing the involved renal artery in TAK patients.MethodsOne hundred fifteen TAK patients with 314 renal arteries were retrospectively analyzed, who were admitted to Peking Union Medical College Hospital between 2017 and 2022. These patients underwent both renal artery ultrasonography and angiography within a 4-week period. Specifically, the study compared seven ultrasonic parameters across groups categorized by the severity of renal artery stenosis (RAS), including noninvolvement, < 50% stenosis, 50–69% stenosis, and 70–99% stenosis. Receiver operating characteristic (ROC) curves were employed to determine the optimal threshold values for renal artery peak systolic velocity (RPSV), renal-aortic PSV ratio (RAR), and renal-interlobar PSV ratio (RIR) in order to diagnose various degrees of RAS in TAK patients.ResultsStatistically significant differences were observed in RAR and RIR among the four groups (all P < 0.05). However, no statistically significant differences were found in RPSV and AT between the moderate stenosis group (50–69% stenosis) and the severe stenosis group (70–99% stenosis). The discrimination of interlobar PSV (IPSV) and interlobar RI (IRI) was not significant, and IEDV did not show statistical significance among the four groups.For TAK patients, the recommended thresholds of RPSV for the diagnosis of renal artery involvement (RAI), ≥ 50% RAS, and ≥ 70% RAS were determined to be 143 cm/s, 152 cm/s, and 183 cm/s, respectively. The sensitivities, specificities, and accuracies of these thresholds were all found to be greater than 80%. Additionally, the optimal thresholds of RIR for detecting RAI, ≥ 50% RAS, and ≥ 70% RAS were determined to be 4.6, 5.6, and 6.4, respectively, with satisfactory diagnostic efficiencies. The areas under the curve (AUCs) for RPSV and RIR were calculated to be 0.908 and 0.910, respectively, for the diagnosis of ≥ 50% RAS, and 0.876 and 0.882 for the diagnosis of ≥ 70% RAS. When the aortic PSV is greater than or equal to 140 cm/s, the RAR exhibits inadequate diagnostic efficacy. Conversely, when the aortic PSV is less than 140 cm/s, a RAR value of 2.2 or higher can be employed as the diagnostic threshold for identifying RAS of 70% or greater, with a sensitivity of 84.00%, specificity of 89.93%, and an overall accuracy of 89.08%.ConclusionIn the present study, it has been demonstrated that RPSV and RIR possess substantial diagnostic value as ultrasonic parameters for diagnosing RAS in TAK patients. Furthermore, when assessing the diagnostic efficacy of RAR, it is crucial to consider the severity of aortic stenosis as a determining factor.

Endovascular Versus Medical Management of Atherosclerotic Renovascular Disease: Update and Emerging Concepts.

Atherosclerotic renovascular disease is the most frequent cause of renovascular hypertension and its prevalence increases with age and in specific subset of patients, such as those with end-stage chronic kidney disease, heart failure, and coronary artery disease. Besides hypertension, atherosclerotic renovascular disease is responsible for several clinical manifestations, including life-threatening conditions, such as recurrent flash pulmonary edema, rapidly progressive chronic kidney disease, or acute kidney injury. Atherosclerotic renovascular disease is usually part of a more diffuse atherosclerotic process and requires a combination therapy including antihypertensive, antiplatelet and lipid-lowering agents, as well as optimization of antidiabetic treatment, if needed. Besides medical therapy, percutaneous renal angioplasty was supposed to be the most effective therapy for atherosclerotic renovascular disease, by leading to blood flow restoration. However, despite an apparently solid rationale, several randomized clinical trials failed to confirm the favorable effects of percutaneous renal angioplasty on blood pressure control, kidney function, cardiovascular and renal outcomes, previously reported in observational, retrospective and single-center cohorts, switching off the enthusiasm for this procedure. Several studies' limitations may partly account for this failure, including heterogeneity of diagnostic techniques, overestimation of the degree of renal artery stenosis, inappropriate timing of revascularization, multiple protocol revisions, frequent crossovers, and most importantly exclusion of patients at higher likelihood to respond to angioplasty. The purpose of this review is to summarize studies' potential weaknesses and provide guidance to the clinician for identification of patients who may benefit most from revascularization.

Role of Contrast-Enhanced Ultrasound in the Evaluation of Patients With Suspected Renal Arterial Stenosis.

ObjectivesTo explore the role of Contrast-enhanced ultrasound (CEUS) in the evaluation of patients with suspected renal artery stenosis and analyze the causes of the misdiagnosis and missed diagnosis.MethodsThe data of 40 patients (80 renal arteries) diagnosed with RAS by CEUS in Beijing Hospital from September 2018 to October 2020 were compared with their digital subtraction angiography (DSA) results to analyze the causes underlying missed diagnosis and misdiagnosis of RAS by CEUS.Results1. Compared with the gold standard DSA results, the AUC of the ROC curve of CEUS in detecting normal renal artery and renal artery stenosis was 0.961, the sensitivity was 96.4%, the specificity was 95.8%, and the Kappa value of the consistency analysis was 0.912 (P < 0.01); 2. Compared with the gold standard DSA results, the ROC curve of CEUS in distinguishing renal artery stenosis ≥70% from <70% stenosis has an AUC of 0.916, a sensitivity of 90.9%, a specificity of 92.3%, and the Kappa value of the consistency analysis is 0.77 (P < 0.01); 3. CEUS missed two cases (one for mild stenosis and one for moderate stenosis), and the detection rate of renal artery stenosis was 97.5% (78/80); A total of 65 renal arteries diagnosed by CEUS were consistent with DSA, and the diagnostic accuracy of CEUS for the degree of stenosis was 81.25% (65/80); Among the 13 misdiagnosed renal arteries, 4 of them can be corrected to the same degree as DSA by the reference to hemodynamic index, and the diagnosis rate of the degree of renal artery stenosis by ultrasonography (combined with CEUS and hemodynamic indicators) can be improved to 86.25%.Conclusions1. CEUS can clearly show the renal arteries, and is consistent with DSA in distinguishing normal renal artery stenosis from renal artery stenosis, as well as renal artery stenosis ≥70% and <70% stenosis; 2. CEUS showed good performance in detecting normal renal artery and renal artery stenosis, and the missed diagnosis is concentrated on mild and moderate stenosis; 3. CEUS combined with hemodynamic indicators (Doppler ultrasound) can improve the accurate diagnosis rate of renal artery stenosis by ultrasonography; 4. The most important factor for the accurate diagnosis of renal artery stenosis by CEUS is the operator's standardized examination, which is not only related to the duration of the operator has been engaged in this inspection, but also related to whether the operator has received professional training in relevant aspects. These all indicate the necessity and importance of the standardized operation of renal artery contrast-enhanced ultrasound examination, and professional training should be given to operators.

Evaluation of Endovascular Therapy for Unilateral Atherosclerotic Renal Artery Stenosis Using Measurements of Differential Renal Function

Abstract Background To evaluate the efficacy of endovascular therapy in patients with unilateral arteriosclerotic renal artery stenosis using nuclide renal dynamic imaging and to analyze the influencing factors that may affect the renal function. Methods A retrospective analysis was made on 60 patients with &amp;gt;70% unilateral arteriosclerotic renal artery stenosis who underwent renal artery stent implantation. Serum creatinine, urea nitrogen, renal artery color Doppler ultrasonography, and renal dynamic imaging results were obtained before and after 1 year of operation. A regression model was used to analyze the influencing factors. Results All patients underwent balloon dilatation and stenting of the affected renal artery. The immediate intervention success rate was 100%. The residual stenosis of the affected renal artery was less than 20%. No serious complications occurred during the perioperative period. After operation, systolic blood and diastolic blood pressures were improved (P &amp;lt; 0.01), the serum creatinine was stable (P = 0.25), and the degree of renal artery stenosis of the affected side was relieved significantly (P &amp;lt; 0.01). One year after operation, the patency rate of renal artery stent was 85%. Based on the changes of differential glomerular filtration rate of the affected side, 40 patients (66.7%) were improved while 20 patients (33.3%) were not. A linear regression analysis showed that the renal insufficiency of the affected side before operation was the only significant influencing factor (B = 0.50, P &amp;lt; 0.01). Conclusions Renal artery stenting is safe and effective in the treatment of unilateral renal artery stenosis. One-year patency rate is 85%. Two-thirds of the patients have an improved renal function after operation. The patients with preoperative renal insufficiency of affected side are more likely to benefit from renal artery stenting.

Influence of renal artery stenosis morphology on hemodynamics

Objective Currently, the clinical classification of the severity of renal artery stenosis (RAS) solely depends on the degree of stenosis. In addition, when the stenosis degree is between 50% and 70%, the clinical strategy is decided based on whether the RAS is hemodynamically significant. In this study, the influence of RAS morphological parameters on hemodynamics was numerically analyzed to provide a theoretical basis for clinical treatment. Methods Idealized RAS models were established to investigate the hemodynamic effects of the stenosis length, asymmetric stenosis, and direction of the opening of the renal artery. Results The longer the stenosis length, the greater is the ratio of the low time-averaged wall shear stress (WSS) and high oscillatory shear index (OSI) area distal stenosis (when the stenosis area is the same). In addition, asymmetric stenosis leads to a significant increase in the ratio of the renal artery peak systolic velocity (R-PSV) and the abdominal aorta peak systolic velocity (A-PSV) when the stenosis area is 60–70%. Furthermore, the fraction flow reserve (FFR) of the RAS model with 12 mm stenosis length, upward eccentricity and upward direction of renal artery opening was approximately equal to the cumulative value of the influence of different stenosis morphologies on FFR. Conclusion An assessment of the severity of RAS should consider the stenosis area and other morphological parameters, including the length and asymmetry of RAS as well as the direction of the opening of renal artery, particularly when the stenosis degree of RAS is between 50% and 70%.

Clinical value of color Doppler ultrasonography in evaluating the degree of atherosclerotic renal artery stenosis in the elderly by ROC curve analysis

Objective To evaluate the clinical value of color Doppler ultrasonography (CDFI) in evaluating the degree of atherosclerotic renal artery stenosis (ARAS) in the elderly by using ROC curve analysis. Methods From March 2015 to September 2018, 117 patients with ARAS admitted to Anji Branch of the First Affiliated Hospital of Medical College of Zhejiang University were selected.All patients underwent color Doppler ultrasonography and renal artery angiography.Renal artery angiography was used as the gold standard.The diagnostic value of color Doppler ultrasonography for ARAS was analyzed.The changes of color Doppler ultrasonography indicators of renal artery in different degrees of stenosis were compared.The ROC curve was used to analyze the value of color Doppler ultrasound in evaluating the degree of atherosclerotic renal artery stenosis in the elderly. Results Using renal arteriography as the gold standard, the sensitivity of color ultrasonography for ARAS was 82.17% (129/157), and the specificity of diagnosis was 80.52% (62/77). The PSV [(227.59±34.28)cm/s] and EDV [(57.39±6.48)cm/s] in the severe stenosis group were higher than those in the moderate stenosis group [(183.84±41.05) cm/s and (50.29±5.22)cm/s] (t=6.269, 6.506, all P<0.05) and the mild stenosis group [(128.47±52.35)cm/s and (37.52±7.15)cm/s] (t=10.517, 12.813, all P<0.05) and the non-stenosis group [(86.49±28.94)cm/s and (26.48±5.02)cm/s] (t=18.598, 21.971, all P<0.05). The RI in the severe stenosis group[(0.41±0.07)] was lower than that in the moderate stenosis group [(0.47±0.06)] (t=4.966, P<0.05) and the mild stenosis group [(0.52±0.07)] (t=8.496, P<0.05) and the no stenosis group [(0.70±0.11)] (t=17.101, P<0.05). The ROC curve was used to analyze the diagnostic value of color ultrasound parameters for moderate and severe stenosis.The area under the diagnostic curve of PSV, EDV and RI for moderate and severe stenosis was 0.869, 0.932 and 0.937, respectively. Conclusion CDFI plays an important role in the early diagnosis and clinical screening of elderly patients with ARAS.It is helpful to judge the degree of renal artery stenosis and evaluate the condition of the patients.It is non-invasive, simple and inexpensive, and worthy of clinical application. Key words: Ultrasonography, doppler, color; ROC curve; Atherosclerotic renal artery stenosis; Blood flow velocity; End-diastolic flow velocity; Peak velocity ratio; Resistance index; Aged

The Relationship Between Renal Artery Stenosis and Degree of Angio Score on the Lower Extremity Peripheral Arterial Disease in Cipto Mangunkusumo Hospital

Introduction: The most common cause of the peripheral arterial disease (PAD) is atherosclerosis. PAD is associated with other atherosclerotic diseases such as renal artery stenosis (RAS). Life expectancy decreases in patients with RAS, especially those whose stenosis is above 60% but has not reached the stage of chronic kidney failure. This study aims to determine the prevalence of RAS in PAD patients, the relationship between angiographic scoring system (ANGIO Score), history of hypertension, and diabetes mellitus with the degree of RAS. Method: This research was a cross-sectional study conducted at Cipto Mangunkusumo Hospital from February to May 2019. Patients with a diagnosis of lower extremity PAD and had been assessed with CT angiography examination, were included in this study. The degree of RAS and ANGIO Score were calculated. Sampling was done by the total sampling method. Results Most patients were women 33 (50.8%), while men were 32 (49.2%). 90.8% of the patients had diabetes, while 61.5% of the sample had hypertension. Grade 1 RAS was the most found. There was no correlation between ANGIO Score on age, sex, and diabetes mellitus, but there was a significant relationship with hypertension. There was a relationship between RAS with age and hypertension, but there was no relationship with diabetes mellitus and gender. ANGIO Score and RAS had a significant relationship (p &lt;0.001). Conclusion: There was a relationship between the ANGIO Score and the severity of RAS. The cut-off score of 9 for the ANGIO Score had a sensitivity of 85.7% and a specificity of 61.4% for predicting RAS. Keywords: peripheral arterial disease, angiographic scoring system, renal artery stenosis, CT angiography

AB063. Gore PROPATEN Vascular Graft vs. great saphenous vein graft for aorto-renal artery bypass in pediatric/adolescent patients of Takayasu arteritis

BackgroundFor patients of Takayasu arteritis with severe renal artery stenosis, the graft restenosis rate after interventional therapy is 77.3%, thus aorto-renal artery bypass would be the main treatment for this type of patients and can decrease the restenosis rate.MethodsFrom Mar 1993 to Dec 2017, 31 cases of pediatric/adolescent Takayasu arteritis patients with severe renal artery stenosis were admitted to our center. All patients were diagnosed by the American College of Rheumatology 1990 criteria for the classification of Takayasu arteritis. All patients underwent aorto-renal artery bypass. The location and degree of renal artery stenosis were evaluated by preoperative total aortic enhanced computed tomography (CT) scan, and the potential position of renal artery trunk or renal artery branches for graft anastomosis was also selected by analysis of CT. Saphenous vein graft (SVG) or Gore PROPATEN Vascular Graft was used for the bypass. The procedure of surgery was as follows: using median incision or lumbar incision to expose the abdominal aorta and renal artery trunk and its branches; using 8-cm SVG or Gore PROPATEN Vascular Graft as the graft for bypass; the distal was anastomosed to abdominal aorta end-to-side, the proximal was anastomosed to renal artery trunk or branch side-to-side. All patients were treated with glucocorticoid for 3 months postoperatively, and were regularly followed up by vascular ultrasonography and aortic enhanced CT scan.ResultsIn this study there were 24 female and 7 male patients. The patients’ age was 8–18 years. The follow-up time was 3–300 months. The average blood pressure was (175±26)/(100±19) mmHg before operation, and decreased to (139±15)/(85±13) mmHg after operation. SVG graft was used in 26 patients and Gore PROPATEN Vascular Graft in five patients. In SVG graft group, the graft restenosis occurred in seven patients in 1 year after surgery, and aneurysmal degeneration occurred in three patients (incidence of 10%) in 5–7 years postoperatively and was treated with endovascular exclusion; while in Gore PROPATEN Vascular Graft group there was such complications.ConclusionsAorto-renal artery bypass is an effective treatment for Takayasu arteritis patients with severe stenosis of renal artery trunk, but using SVG graft for the bypass has a high risk of late aneurysmal degeneration of the graft. In pediatric/adolescent patients of Takayasu arteritis, the requirement for the future growth and the long-term control of disease should be considered, thus these patients could benefit more from the use of Gore PROPATEN Vascular Graft in aorto-renal artery bypass, by reducing the incidence of aneurysmal degeneration while guaranteeing the patency of the bypass graft.

The effect of revascularization in patients with anatomically significant atherosclerotic renovascular disease presenting with high-risk clinical features.

Patients with atherosclerotic renovascular disease (ARVD) and high-risk clinical presentations have largely been excluded from randomized controlled trials comparing renal revascularization and optimal medical therapy. Here, we explore the effect of revascularization on death, progression to end-stage kidney disease (ESKD) and cardiovascular events (CVE) in a highly selected cohort of patients with ARVD. All patients with a radiological diagnosis of ARVD referred to our tertiary centre have been recruited into a single-centre cohort study between 1986 and 2014. Patients with ≥70% unilateral or bilateral ARVD together with one or more of the following putative high-risk presentations were designated 'high-risk': flash pulmonary oedema (FPE), severe hypertension, rapidly deteriorating renal function. The effect of revascularization on clinical outcomes in high-risk patients, patients with bilateral severe ARVD and those with <1 g proteinuria at baseline was compared with 'control' patients who had the same degree of renal artery stenosis (RAS) but did not exhibit these features. Median follow-up was 58.4 months [interquartile range (IQR) 25.4-97.3]. Revascularization was associated with a reduced risk of progression to ESKD, CVE and all combined events in patients with rapidly deteriorating renal function [ESKD: hazard ratio (HR) 0.47 (95% confidence interval, CI, 0.25-0.85), P = 0.01; CVE: HR 0.51 (95% CI 0.29-0.91), P = 0.02; Any: HR 0.51 (95% CI 0.29-0.90), P = 0.02]. High-risk patients with bilateral ≥70% RAS and those with <1 g/day baseline proteinuria also had significantly better renal and cardiovascular outcomes post-revascularization when compared with controls. Our results indicate that revascularization may be of benefit in patients with anatomically significant RAS who present with rapidly deteriorating renal function, especially in the presence of severe bilateral ARVD or <1 g/day proteinuria.

OP.1C.05] THE POLISH REGISTRY FOR FIBROMUSCULAR DYSPLASIA - THE PRELIMINARY REPORT ON DISTRIBUTION OF VASCULAR BED INVOLVEMENT AND COMPLICATIONS IN PATIENTS ENROLLED IN ARCADIA-POL STUDY

Objective: To present preliminary evaluation of vascular bed involvement and vascular complications in patients with fibromuscular dysplasia (FMD) enrolled to ARCADIA-POL registry. Design and method: The first 84 patients (59F[70.2%], 25M[29.8%], mean age: 42.5 ± 14.8 years, range:18–72) with confirmed FMD in any vascular bed were enrolled in 2015 in ARCADIA-POL registry (instituted on the basis of as Polish-French collaboration). A standardized FMD data form was used for data collection. All patients underwent detailed clinical evaluation including ambulatory blood pressure monitoring (ABPM), biochemical evaluation, biobanking, duplex Doppler of carotid and abdominal arteries and whole body angio-CT. Results: In the analyzed group FMD was identified in renal arteries in 74 (88.1%) patients, bilaterally in 29 (39.2%) patients as well as in carotid, intracranial and vertebral arteries in 14 (16.7%), 14 (16.7%) and 6 (7.1%) patients, respectively. FMD was also identified in celiac trunk and mesenteric, iliac and splenic arteries in 12(14.3 %), 7(8.3%), and 6(7.1%) patients, respectively. Evaluating degree of renal artery stenosis on duplex Doppler and angio-CT, significant stenosis was identified in 19 (25.7%) patients (in this group 8 patients had restenosis after previous intervention) whereas non-significant stenosis was found in 55 (74.3%) patients (in this group 9 patients had a history of intervention on renal artery). In 39 patients (46.4%) FMD was identified in two or more vascular bed. Two vascular beds were involved in 31% (26 pts), three in 11.9% (10 pts), four in 2.4 % (2 pts) and five in 1.2 % (1 pt). Arterial dissection(s) and aneurysms in various vascular beds were found in 14.3% and 26.2% of patients respectively. Severe FMD defined as first onset of FMD <30 years, affecting at least 3 vascular beds complicated with thrombosis or dissection requiring an endovascular or surgical repair, with no inflammatory background was identified in 2 patients (2.4%). Conclusions: Preliminary data of ARCADIA-POL registry showed that renal FMD was the most frequent, but also cerebrovascular FMD occurred in relatively large proportion of patients. Our data revealed high incidence of FMD lesions coexisting in different vascular beds as well as relatively frequent occurrence of vascular complications.

Duplex derived intrarenal resistance index correlates with invasive pressure gradient measurements in detecting relevant unilateral renal artery stenosis.

The purpose of this study was to assess the correlation between the transstenotic pressure gradient as determined by a pressure wire and the decrease in the intrarenal resistance index (RI) > 0.05 measured by duplex ultrasound in significant unilateral renal artery stenosis (RAS). Intravascular ultrasound (IVUS) was correlated to the angiographic degree of RAS. In 17 patients, transstenotic pressure gradient measurements, IVUS and RI measurements were obtained before and after stenting. After stenting, graded stenosis was created by progressive balloon catheter inflation. Stenosis severity was expressed as the ratio of the distal pressure (Pd) corrected for aortic pressure (Pa). The balloon inflation pressure was adjusted to create a stenosis with Pd/Pa ratio 1.0 to 0.7. In parallel, RI measurements were performed in the affected kidney and compared to the contralateral kidney for the calculation of the side-difference in RI. IVUS was performed to correlate the cross-sectional degree of stenosis with quantitative angiography (QA). In 60 out 68 measurements, the RI difference (decline > 0.05) correlated with a Pd/Pa ratio < 0.9; this correlation was significant by linear regression analysis (p < 0.001). The preinterventional mean degree of stenosis was 63.4 % + 16.1 (24.6 - 84.6 %) as assessed by QA and 76.7 % + 13.2 % (47 - 92 %) as assessed by IVUS, showing a significant correlation (p < 0.035). In unilateral RAS, a drop in RI > 0.05 as compared to the unaffected kidney correlates to an invasively measured Pd/Pa ratio < 0.9, which is regarded as a significant pressure gradient associated with increased renin production, which promotes renovascular hypertension. QA underestimates RAS severity as compared to IVUS.

Autophagy Portends the Level of Cardiac Hypertrophy in Experimental Hypertensive Swine Model.

Left ventricular (LV) hypertrophy (LVH) plays an important role in hypertensive heart disease, and may be accompanied by myocardial autophagy. However, the pattern of autophagy during evolution of LVH is unclear. We hypothesized that autophagy activation indicates advancing cardiac LVH with tissue remodeling. Ten domestic pigs with a 10-week unilateral renovascular hypertension (HTN) were classified as mild or moderate HTN (n = 5 each group) based on the degree of renal artery stenosis (above or below 75%). Seven normal pigs served as controls. Left ventricular remodeling, function, and microvascular density were assessed using multi-detector- and micro-computed tomography and histology. Markers of myocardial autophagic and endoplasmic reticulum (ER) stress-related unfolded protein response (UPR), apoptosis, and fibrosis were examined ex vivo. Both HTN groups had increased myocyte cross-sectional area, but it was greater in moderate HTN, accompanied by elevated LV muscle-mass. Moderate, but not mild HTN, also showed impaired microvascular density and impaired myocardial perfusion. Autophagy mediators were unaltered in mild HTN but UPR markers were increased, while in moderate HTN they were all upregulated, whereas UPR markers were suppressed. Myocardial apoptosis and fibrosis were also greater in moderate HTN. Autophagic proteins were correlated with LVH and fibrosis. Autophagic activity is stimulated during the exacerbation of LVH, following a transient early increase in ER stress, and may be involved in the progression of cardiac remodeling in renovascular hypertensive heart disease.

Where now in the management of renal artery stenosis? Implications of the ASTRAL and CORAL trials.

The neutral findings of Angioplasty and Stenting for Renal Artery Lesions and Cardiovascular Outcomes in Renal Artery Lesions trials have shown that unselected revascularization does not improve outcomes in atherosclerotic renovascular disease (ARVD). This review highlights recent translational, clinical and epidemiological studies and suggests directions for future research. Imaging studies show that the degree of renal artery stenosis is not the most important determinant of outcome and response to therapies in ARVD. Porcine models have established a better understanding of the microvascular and inflammatory changes that occur in ARVD. Biomarkers of inflammation and cardiovascular dysfunction may be informative but do not yet help assess prognosis or response to treatment. Stem cell therapies show promise in animal models but have yet to translate into clinical practice. Analysis of patient subgroups with high-risk presentations of ARVD has provided new insights into treatment response and may guide future studies. It is time to reframe thinking and research in ARVD. We need better ways to identify patients likely to benefit from revascularization and to improve response to treatment in these individuals. Many preclinical studies show promise, but these are often small scale and difficult to replicate. Future work should focus on establishing an international disease registry as a foundation for collaborative research.

Renal artery stenting: early results

Abstract Background Atherosclerotic renovascular disease (ARVD) is defined as renal artery stenosis with an occlusion of 60% or more. It is an established cause of resistant hypertension and renal insufficiency. ARVD is evaluated using renal artery duplex ultrasound, which measures the degree of renal artery stenosis and renal resistance index. Treatment with renal artery balloon angioplasty and stents has been shown to improve blood pressure and renal function in some patients. Aim of the study This was a prospective study evaluating the early effects of renal artery angioplasty and stenting in patients with ARVD as regards the blood pressure and renal function. Methods During March 2009 to September 2011, 37 patients (21 men and 16 women) with ARVD (unilateral or bilateral), resistant hypertension, and renal impairment were selected and divided into two groups: group A (25 patients) comprised patients who underwent renal artery balloon angioplasty and stenting (intervention group) and group B (12 patients) comprised those who were kept on medical treatment as controls and followed up without intervention. Results Two weeks after intervention, eight patients (32%) stopped one medication, seven patients (28%) stopped two medications (i.e. one antihypertensive medication only), and five patients (20%) stopped all medications, whereas the blood pressure did not change in five patients (20%). The average mean systolic blood pressure of group A was 140 mmHg and the average serum creatinine level was 2.1. As regards group B, the average mean systolic blood pressure was 170 mmHg for patients who were on three antihypertensive medications, and the average serum creatinine level was 2.4. Conclusion The main effect of renal artery revascularization in ARVD is on blood pressure control in patients with resistant hypertension, with minimal influence on the renal function.

Relation of Pulse and Systolic and Mean Blood Pressure to Severe Renal Artery Stenosis in Patients Undergoing Concurrent Coronary and Renal Angiography

Abrupt onset of renal ischemia is associated with increased blood pressure (BP), but it is unknown whether BP remains elevated in patients with chronic severe atherosclerotic renal artery stenosis (RAS). Patients undergoing coronary angiography who had concurrent renal angiography were divided into 3 groups: severe (stenosis ≥70% diameter reduction), moderate (10%-69%), and minimal RAS. Aortic BP was measured at the time of angiography. Renal angiography was performed in 762 (5.4%) of 14,181 patients undergoing coronary angiography. The mean age was 62 ± 12 years, 52% were women, 93% had hypertension, and 42% had diabetes mellitus. Minimal, moderate, or severe RAS was found in 62%, 30%, and 9% of patients. Patients with minimal RAS were younger, less likely to have hypercholesterolemia or coronary artery disease, and had a lower creatinine than patients with severe RAS. Severe RAS was associated with a lower diastolic BP and mean BP and a higher pulse pressure (PP), but there was no difference in systolic BP or the number of antihypertensive medications between the 3 groups. The degree of RAS had a weak positive correlation with PP, a weak negative correlation with diastolic BP, and almost no correlation with systolic BP or mean BP. In multivariate linear regression analysis, there was an association between severity of RAS and PP but not with mean BP or systolic BP. In conclusion, PP, but not systolic BP, diastolic BP, mean BP, or number of antihypertensive medications, was elevated in patients with severe RAS.

Evaluation of Renal Artery in Hypertensive Patients by Unenhanced MR Angiography Using Spatial Labeling With Multiple Inversion Pulses Sequence and by CT Angiography

The purposes of this study were to determine the performance of a new unenhanced MR angiography (MRA) sequence, spatial labeling with multiple inversion pulses (SLEEK), with regard to its ability to present the renal arteries and to reveal renal artery disease in patients with secondary hypertension. Unenhanced MRA using SLEEK was performed on a 1.5-T MRI system for assessing renal arteries in 50 patients with hypertension. Then all patients underwent CT angiography (CTA) within 1-7 days. The ability to present the renal arteries and to reveal renal artery disease with SLEEK was evaluated by two experienced radiologists and was compared with CTA results using a joint reading performed in consensus. Forty-six patients with hypertension successfully underwent SLEEK MRA. A total of 119 renal arteries were assessed, including 86 normal arteries, 26 with stenoses, and seven with fibromuscular dysplasia on CTA. There was excellent correlation between SLEEK and CTA in presenting the degree of renal artery stenosis (r(s) = 0.851; p < 0.05). SLEEK was superior to CTA in revealing the third- and fourth-order segmental branches in the renal parenchyma (p < 0.05). SLEEK has the advantage of avoiding interference from vertebra, atherosclerotic plaques, and early venous system enhancement. Unenhanced MRA using SLEEK is a reliable diagnostic method for evaluating renal artery disease and revealing segmental branches in the renal parenchyma. It is relatively inexpensive and is not associated with renal complications. It can be used as an alternative to CTA for screening for renal artery disease, especially in patients with hypertension and renal insufficiency.

The effect of revascularization of renal artery stenosis on renal perfusion in patients with atherosclerotic renovascular disease

Only a small fraction of patients with atherosclerotic renovascular disease (ARVD) treated with revascularization have improved renal function after the procedure. It has been suggested that this may be due to effects of renal microvascular disease. Our aim was to measure the effect of renal artery stenosis (RAS) revascularization on renal perfusion in patients with renovascular disease. Seventeen renovascular disease patients were treated by dilatation of unilateral (N = 8) or bilateral (N = 9) RAS (N = 23 kidneys), mainly because of uncontrolled or refractory hypertension. The patients were studied before and after (103 ± 29 days) the procedure. Renal perfusion was measured using quantitative positron emission tomography (PET) perfusion imaging. Although renal perfusion correlated inversely with the degree of RAS in patients with renovascular disease, it did not change after revascularization. Our data support the notion of former clinical trials that angiographic severity of RAS does not determine the response to revascularization. Quantitative PET perfusion imaging is a promising tool to noninvasively measure renal perfusion for the assessment of physiological impact of RAS.

Early superoxide scavenging accelerates renal microvascular rarefaction and damage in the stenotic kidney

Renal artery stenosis (RAS), the main cause of chronic renovascular disease (RVD), is associated with significant oxidative stress. Chronic RVD induces renal injury partly by promoting renal microvascular (MV) damage and blunting MV repair in the stenotic kidney. We tested the hypothesis that superoxide anion plays a pivotal role in MV dysfunction, reduction of MV density, and progression of renal injury in the stenotic kidney. RAS was induced in 14 domestic pigs and observed for 6 wk. Seven RAS pigs were chronically treated with the superoxide dismutase mimetic tempol (RAS+T) to reduce oxidative stress. Single-kidney hemodynamics and function were quantified in vivo using multidetector computer tomography (CT) and renal MV density was quantified ex vivo using micro-CT. Expression of angiogenic, inflammatory, and apoptotic factors was measured in renal tissue, and renal apoptosis and fibrosis were quantified in tissue sections. The degree of RAS and blood pressure were similarly increased in RAS and RAS+T. Renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced in the stenotic kidney (280.1 ± 36.8 and 34.2 ± 3.1 ml/min, P < 0.05 vs. control). RAS+T kidneys showed preserved GFR (58.5 ± 6.3 ml/min, P = not significant vs. control) but a similar decreases in RBF (293.6 ± 85.2 ml/min) and further decreases in MV density compared with RAS. These changes were accompanied by blunted angiogenic signaling and increased apoptosis and fibrosis in the stenotic kidney of RAS+T compared with RAS. The current study shows that tempol administration provided limited protection to the stenotic kidney. Despite preserved GFR, renal perfusion was not improved by tempol, and MV density was further reduced compared with untreated RAS, associated with increased renal apoptosis and fibrosis. These results suggest that a tight balance of the renal redox status is necessary for a normal MV repair response to injury, at least at the early stage of RVD, and raise caution regarding antioxidant strategies in RAS.