Significant Renal Artery Stenosis Research Articles

Balloon angioplasty, with and without stenting, versus medical therapy for hypertensive patients with renal artery stenosis.

Atherosclerotic renal artery stenosis is the most common cause of secondary hypertension. Balloon angioplasty with stenting is widely used for the treatment of hypertensive patients with renal artery stenosis but the effectiveness of this procedure in treating hypertension, improving renal function and preventing adverse cardiovascular and renal events remains uncertain. This is an update, to include the results of recent, important large trials, of a review first published in 2003. To compare the effectiveness of balloon angioplasty (with and without stenting) with medical therapy for the treatment of atherosclerotic renal artery stenosis in patients with hypertension. The following outcomes were compared: blood pressure control, renal function, frequency of cardiovascular and renal adverse events, presence or absence of restenosis of the renal artery, side effects of medical therapy, numbers and defined daily doses of antihypertensive drugs. For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 2014) and CENTRAL (2014, Issue 4). Bibliographies were also reviewed and trial authors were contacted for more information. Randomised controlled trials (RCTs) comparing balloon angioplasty with medical therapy in hypertensive patients with haemodynamically significant renal artery stenosis (greater than 50% reduction in luminal diameter) and with a minimum follow-up of six months. Data were extracted independently on trial design, participants, interventions and outcome measures. A formal meta-analysis was completed to assess the effect on blood pressure, renal function and cardiovascular and renal adverse events. Peto's odds ratios (ORs) and corresponding 95% confidence intervals (CI) for dichotomous outcomes and mean differences (MD) and corresponding 95% CIs for continuous variables were calculated. Eight RCTs involving 2222 participants with renal artery stenosis were included in the review. The overall quality of evidence included in this review was moderate. Limited pooling of results was possible due to the variable presentation of some of the trial outcomes. Meta-analysis of the four studies reporting change in diastolic blood pressure (BP) found a small improvement in diastolic BP in the angioplasty group (MD -2.00 mmHg; 95% CI -3.72 to -0.27) whilst the meta-analysis of the five studies reporting change in systolic BP did not find any evidence of significant improvement (MD -1.07 mmHg; 95% CI -3.45 to 1.30). There was no significant effect on renal function as measured by serum creatinine (MD -7.99 µmol/L; 95% CI -22.6 to 6.62). Meta-analysis of the three studies that reported the mean number of antihypertensive drugs found a small decrease in antihypertensive drug requirements for the angioplasty group (MD -0.18; 95% CI -0.34 to -0.03). Repeat angiography was only performed on a small number of participants in a single trial and it was therefore not possible to comment on restenosis of the renal artery following balloon angioplasty. Based on the results of the seven studies that reported cardiovascular and renal clinical outcomes there were no differences in cardiovascular (OR 0.91; 95% CI 0.75 to 1.11) or renal adverse events (OR 1.02; 95% CI 0.75 to 1.38) between the angioplasty and medical treatment groups. A small number of procedural complications of balloon angioplasty were reported (haematoma at the site of catheter insertion (6.5%), femoral artery pseudoaneurysm (0.7%), renal artery or kidney perforation or dissection (2.5%) as well as peri-procedural deaths (0.4%)). No side effects of medical therapy were reported. The available data are insufficient to conclude that revascularisation in the form of balloon angioplasty, with or without stenting, is superior to medical therapy for the treatment of atherosclerotic renal artery stenosis in patients with hypertension. However, balloon angioplasty results in a small improvement in diastolic blood pressure and a small reduction in antihypertensive drug requirements. Balloon angioplasty appears safe and results in similar numbers of cardiovascular and renal adverse events to medical therapy.

Non-Hemodynamically Significant Renal Artery Stenosis Predicts Cardiovascular Events in Persons with Ischemic Heart Disease

Background/Aims: Recently, we reported that small renal arteries, defined by a low reference diameter (RD) or minimal luminal diameter (MD), are independently associated with a low GFR, resistant hypertension, and onset of contrast-induced nephropathy and suggested a post-hoc analysis of CORAL trial based on RD categories. Here we hypothesized that RD and MD are markers of nontraditional cardiovascular risk factors and tested whether low RD and MD could impact the prognosis of patients with ischemic heart disease. Methods: Prospective cohort study. We used proportional hazards models to analyze the first onset of cardiovascular events in relation with RD, MD, or percentage of renal artery stenosis (RAS) in those with low-to-moderate RAS (10-70%) (n = 181). Results: During the median follow-up of 4.5 (range, 0.1-5) years, 27.8% participants (n = 623; mean age, 64 years; 29% women) experienced a cardiovascular event (35.4% in those with RAS 10-70%). The presence of low-to-moderate RAS was associated with cardiovascular events. In these subjects, those with low MD were associated with a higher risk of cardiovascular events (MD >4.2 mm, HR: 1; MD 3.2-4.2 mm, HR: 1.66, 95% CI: 0.74-3.72, p = 0.22; MD <3.2 mm, HR: 3.72, 95% CI: 1.65-8.40, p = 0.002). When MD was added to a standard risk-factor model, risk prediction improvement was by 4.1%. Results were qualitatively similar if MD was replaced by RD or percentage of stenosis, but with smaller improvement of risk prediction and model fit. Conclusions: In patients with ischemic heart disease and low-to-moderate RAS, MD is a significant predictor of cardiovascular events, improves risk prediction, and may represent a valuable biomarker of cardiovascular disease risk. i 2014 S. Karger AG, Basel

Duplex scanning has a limited role in the evaluation of patients with renal failure

Although common indications for renal duplex scanning (RDS) include hypertension (HT) and renal failure (RF), the role of RDS in the evaluation of patients with RF is not known. The goal of this study was to define ultrasound findings with predictive or discriminatory value in patients with RF and to identify patients undergoing a renal artery intervention as a result of RDS findings. We conducted a retrospective review of 214 consecutive patients referred to an Intersocietal Accreditation Commission-accredited vascular laboratory for an initial RDS from January 1, 2010, to June 30, 2010. RDS included direct ultrasound evaluation of the main renal vessels and renal parenchyma. Significant renal artery stenosis of ≥ 60% diameter reduction was indicated by a renal/aortic velocity ratio ≥ 3.5 and abnormally increased parenchymal resistance by an end-diastolic ratio ≤ 0.3. We separated the patients into two groups by indication for RDS: Group I (HT alone, n = 102) and group II (RF alone or with HT, n = 112). When group I was compared with group II, there were significant differences in gender (50% vs 67% male; P = .013), age (50.9 ± 18.5 vs 60.0 ± 14.8 years; P < .001), mean arterial pressure (103.1 ± 18.8 vs 85.7 ± 17.0 mm Hg; P < .001), and creatinine (0.95 ± 0.35 vs 2.25 ± 1.07 mg/dL; P < .001). In group I patients, 86 (84.3%) had normal parenchymal resistance, whereas in group II patients, 68 (60.7%) had abnormally increased parenchymal resistance unilaterally or bilaterally (P < .001). Unilateral or bilateral renal artery stenosis was identified in six group I patients and in three group II patients (P = .315). Evaluation of group II patients revealed a diagnosis of decompensated congestive heart failure (CHF) and the presence of unilateral or bilateral increased parenchymal resistance in 27 of 68 (39.7%) vs nine of 44 (20.4%) with CHF and normal parenchymal resistance. One renal artery angioplasty was performed in a patient with unilateral renal artery stenosis and fibromuscular dysplasia. Renal artery stenosis is extremely uncommon in patients undergoing RDS for RF, indicating that ischemic nephropathy is rarely a cause of RF in these patients. Abnormally increased renal parenchymal resistance is frequently found in patients being evaluated for RF and is associated with increasing creatinine and age. A diagnosis of CHF is also more common in patients with increased parenchymal resistance. Although patients who undergo RDS for RF rarely require renal artery interventions, ultrasound indices of parenchymal resistance may serve as a marker for renal disease and cardiovascular morbidity. Further studies are required to determine the prognostic significance of these ultrasound findings in the setting of RF.

SCAI expert consensus statement for renal artery stenting appropriate use.

The pathophysiology of atherosclerotic renal artery stenosis (RAS) includes activation of the renin-angiotensin-aldosterone axis with resultant renovascular hypertension. Renal artery stenting has emerged as the primary revascularization strategy in most patients with hemodynamically significant atherosclerotic RAS. Despite the frequency with which hemodynamically significant RAS is observed and high rates of technical success of renal artery stenting, there remains considerable debate among experts regarding the role of medical therapy versus revascularization for renovascular hypertension. Modern, prospective, multicenter registries continue to demonstrate improvement in systolic and diastolic blood pressure with excellent safety profiles in patients with RAS. Modern randomized, controlled clinical trials of optimal medical therapy versus renal stenting particularly designed to demonstrate preservation in renal function after renal artery stenting have demonstrated limited benefit. However, these trials frequently excluded patients that may benefit from renal artery stenting. This document was developed to guide physicians in the modern practical application of renal stenting, to highlight the current limitations in the peer-reviewed literature, to suggest best-practices in the performance of renal stenting and to identify opportunities to advance the field.

THE RELATIONSHIP BETWEEN RENAL ARTERY STENOSIS AND ISCHEMIC NEPHROPATHY

Article type Review article Article history Ischemic nephropathy is defined as a clinically significant progressive reduction in glomerular filtration rate that is usually associated with significant renal artery stenosis (unilateral or bilateral involvement). Atherosclerotic renal artery disease is known as the most common cause of the ischemic nephropathy. These patients may develop secondary hypertension. In addition, epidemiologic data has showed a clear association between atherosclerotic renal artery stenosis and coronary artery disease and other cardiovascular disease. Despite the preserving function of kidney on various autoregulation processes, unusual microvascular function will be resulted due to sustained decline in renal perfusion. The ischemic nephropathy of asymptomatic cases may result in renovascular hypertension and renal failure. The reduction of renal function in these patients might be decreased or stopped by early appropriate diagnosis and also might be treated with renal artery angioplasty or surgery, after medical management. There is a debate about the occurrence of ischemic nephropathy as a result of atherosclerotic renal artery stenosis. In this study we aimed to review the prevalence of ischemic nephropathy due to atherosclerotic renal artery stenosis.

Optimal management of renal artery fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory angiopathy of unknown cause affecting medium-sized (most commonly renal) arteries and causing renovascular hypertension. The most common medial multifocal type of FMD (with the “string of beads” appearance) is more than four times more prevalent in females than in males. FMD accounts for up to 10% of cases of renovascular hypertension. Compared with patients with atherosclerotic renal artery stenosis, patients with FMD are younger, have fewer risk factors for atherosclerosis, and a lower occurrence of atherosclerosis in other vessels. The etiology is multifactorial, including vessel wall ischemia and smoking, as well as hormonal and genetic factors. Intra-arterial digital subtraction angiography is still the gold standard for exclusion or confirmation of renal artery stenosis caused by FMD, at least in young patients, who more often have lesions in branches of the renal artery. For FMD patients with atherosclerosis and those who are older (>50–55 years), significant renal artery stenosis may be confirmed or excluded with ultrasonography. The FMD lesion is typically truncal or distal, whereas atherosclerotic lesions are more often proximal or ostial. Treatment options are medical, endovascular (percutaneous transluminal renal angioplasty [PTRA]), and surgical. Invasive treatment should be considered when hypertension cannot be controlled with antihypertensive drugs and in patients with impaired renal function or ischemic nephropathy. PTRA has become the treatment of choice and normally yields good results, especially in unifocal disease and young patients. Pressure gradients are normally completely abolished, and there is no indication for stent placement. Surgical revascularization is indicated after PTRA complications; thrombosis, perforation, progressive dissection, repeated PTRA failure or restenosis. Centralization of handling is recommended.

Comparing the Diagnostic Accuracy of Contrast-Enhanced Computed Tomographic Angiography and Gadolinium-Enhanced Magnetic Resonance Angiography for the Assessment of Hemodynamically Significant Transplant Renal Artery Stenosis

To compare diagnostic accuracy of contrast-enhanced computed tomographic angiography (CTA) and gadolinium-enhanced magnetic resonance angiography (MRA) for the assessment of hemodynamically significant transplant renal artery stenosis (TRAS). After institutional review board approval, records of 27 patients with TRAS confirmed on digital subtraction angiography (DSA) were retrospectively reviewed. A total of 13 patients had MRA and 14 had CTA before DSA. Two board-certified fellowship-trained radiologists, one each from interventional radiology and body imaging blindly reviewed the DSA and CTA or MRA data, respectively. Sensitivity (SN), specificity (SP), positive predictive value, and negative predictive value of MRA and CTA were estimated using 50% stenosis as the detection threshold for significant TRAS. These parameters were compared between modalities using the Fisher exact test. Bias between MRA or CTA imaging and DSA was tested using the Wilcoxon signed-rank test. Two patients were excluded from the MRA group owing to susceptibility artifacts obscuring the TRAS. The correlation between MRA and DSA measurements of stenosis was r = 0.57 (95% CI:-0.02, 0.87; P = 0.052) and between CTA and DSA measurements was r = 0.63 (95% CI: 0.14, 0.87; P = 0.015); the difference between the 2 techniques was not significant (P = 0.7). Both imaging modalities tended to underestimate the degree of stenosis when compared with DSA. MRA group (SN and SP: 56% and 100%, respectively) and CTA group (SN and SP: 81% and 67%, respectively). There were no significant differences in detection performance between modalities (P>0.3 for all measures). We did not find that either modality had any advantage over the other in terms of measuring or detecting significant stenosis. Accordingly, MRA may be preferred over CTA after positive color Doppler ultrasound screening when not contraindicated owing to lack of ionizing radiation or nephrotoxic iodinated contrast. However, susceptibility of artifacts owing to surgical clips at the anastomosis may limit diagnostic utility of MRA as found in 2 of 13 patients. Trend towards no significant difference between the CTA and enhanced MRA in the detection of hemodynamically significant TRAS.

Renal artery stenting in patients with uncontrolled hypertension: should we? And to whom?

In this issue of the Journal, Chrysant and colleagues evaluated the longer-term efficacy of renal artery stenting with respect to blood pressure (BP) control by analyzing the results of the Safety and Effectiveness Study of the Herculink Elite Renal Stent to Treat Renal Artery Stenosis (HERCULES) trial after 36 months of follow-up. 1 The HERCULES trial was a multicenter, single-arm trial of 202 patients with uncontrolled hypertension caused by atherosclerotic renovascular disease (ARVD) treated by percutaneous renal artery dilatation and renal stent placement. In the original HERCULES trial, the authors found that the absolute reduction in systolic BP (SBP) after 9 months was related to the severity of the baseline hypertension before intervention. In ARVD patients with preprocedure SBP >180 mm Hg and a postprocedure reduction in SBP, the mean reduction recorded at 9 months was 48 mm Hg, while patients with ARVD with a baseline SBP between 140 mm Hg and 160 mm Hg had a decrease of only 23 mm Hg in SBP at 9 months. In addition, this trial demonstrated excellent procedurerelated safety, with a 30-day composite safety endpoint rate of 1.5%. 2 Chrysant and colleagues further hypothesized that if the renal stent used in the initial HERCULES trial maintained renal artery patency over time, then the clinical benefit confirmed in the initial trial should be sustained over time. Based on this hypothesis, the

Interventional radiologic techniques for screening, diagnosis and treatment of patients with renal artery stenosis.

Renal artery stenosis resulting in renovascular hypertension or renal ischemia is a potentially treatable condition that results in increased morbidity and mortality, especially among older individuals. Sophisticated imaging techniques are used for screening and identification of affected patients to guide therapy. Treatment guidelines recommend intervention in patients with significant renal artery stenosis, although recent evidence has questioned the benefit of intervention in certain populations. Current research focuses on improving the specificity of imaging techniques and determining which imaging modalities best identify patients who will benefit from intervention.

A prediction model for renal artery stenosis using carotid ultrasonography measurements in patients undergoing coronary angiography.

BackgroundCarotid intima-media thickness (CIMT) and carotid atherosclerotic plaque (CAP) are well-known indicators of atherosclerosis. However, few studies have reported the value of CIMT and CAP for predicting renal artery stenosis (RAS). We investigated the predictive value of CIMT and CAP for RAS and propose a model for predicting significant RAS in patients undergoing coronary angiography (CAG).MethodsConsecutive patients who underwent renal angiography at the time of CAG in a single center in 2011 were included. RAS ≥50% was considered significant. Multiple logistic regression analysis with step-down variable selection method was used to select the best model for predicting significant RAS and bootstrap resampling was used to validate the best model. A scoring system for predicting significant RAS was developed by adding the closest integers proportional to the coefficients of the regression formula.ResultsSignificant RAS was observed in 60 of 641 patients (9.6%) who underwent CAG. Hypertension, diabetes, significant coronary artery disease (CAD) and chronic kidney disease (CKD) stage ≥3 were more prevalent in patients with significant RAS. Mean age, CIMT and number of anti-hypertensive medications (AHM) were higher and body mass index (BMI) and total cholesterol level were lower in patients with significant RAS. Multiple logistic regression analysis identified significant CAD (odds ratio (OR) 5.6), unilateral CAP (OR 2.6), bilateral CAP (OR 4.9), CKD stage ≥3 (OR 4.8), four or more AHM (OR 4.8), CIMT (OR 2.3), age ≥67 years (OR 2.3) and BMI <22 kg/m2 (OR 2.4) as independent predictors of significant RAS. The scoring system for predicting significant RAS, which included these predictors, had a sensitivity of 83.3% and specificity of 81.6%. The predicted frequency of the scoring system agreed well with the observed frequency of significant RAS (coefficient of determination r2 = 0.957).ConclusionsCIMT and CAP are independent predictors of significant RAS. The proposed scoring system, which includes CIMT and CAP, may be useful for predicting significant RAS in patients undergoing CAG.

Safety and Efficacy of Carbon Dioxide and Intravascular Ultrasound-Guided Stenting for Renal Artery Stenosis in Patients With Chronic Renal Insufficiency

We evaluated the feasibility, safety, and mid-term outcomes of renal artery stenting using carbon dioxide (CO₂) digital subtraction angiography and intravascular ultrasound (IVUS) for patients with renal insufficiency and significant atherosclerotic renal artery stenosis (RAS). Eighteen consecutive patients with chronic renal insufficiency underwent renal artery stenting under the guidance of CO₂ angiography and IVUS without contrast media. Renal function and blood pressure were assessed pre- and postintervention. A total of 27 de novo RAS in 18 patients (15 males; mean age: 72 ± 9 years) with renal insufficiency were treated by renal artery stenting with the combined use of the CO₂ angiography and IVUS without any procedural complications. Although the mean serum creatinine concentration preprocedure and 6 months after treatment did not change (2.7 ± 1.0-2.4 ± 1.1 mg/dL), blood pressure significantly decreased 6 months after stenting (158 ± 10-147 ± 11 mm Hg, P < .01).

Sympathetic Nervous System Moves Toward Center Stage in Cardiovascular Medicine

In 1664, the first anatomically correct depiction of the sympathetic nervous system came from Thomas Willis and his circle of London anatomists,1 included in The Anatomy of the Brain and Nerves , 1664 (Figure 1). This, the first work dedicated completely to the nervous system, also described the arterial loops at the base of the brain, which we now know as the Circle of Willis.1 Christopher Wren, an anatomist member of the group, was the principal illustrator1 before being asked by the City Fathers to turn his talents to town planning, architecture, and cathedral building after the 1666 Great Fire of London. Figure 1. An illustration of the human sympathetic nerves of the neck and thorax, from The Anatomy of the Brain and Sympathetic Nerves , published in 1664 by Thomas Willis and reproduced in Soul Made Flesh .1 Almost 2 centuries later, subsequent microscopic examination demonstrated that blood vessel walls were densely innervated, leading Stelling in 18402 to correctly conclude that these vasomotor fibers were in fact sympathetic nerves that were carried from the central nervous system to the blood vessels. In the mid-19th century, celebrated European physiologists, including Brown-Sequard, Waller, and Bernard,2 built on these observations, demonstrating vasoconstriction with electrical stimulation of the cut nerves and vasodilatation on nerve section, which indicated that the sympathetic fibers exerted a tonic, vasoconstrictor influence. The pressor nerves had gained recognition. Identification of the sympathetic neurotransmitter proved to be difficult. Claims for epinephrine3,4 and the hypothetical sympathins I and E confused the picture. Ulf von Euler compared bioassay responses of epinephrine, norepinephrine, and dihydroxy norephedrine with those of cattle splenic nerve extract, by testing blood pressure (BP) responses in the anesthetized cat and contractile responses in the isolated pregnant rabbit uterus, to definitively demonstrate the …

Transcatheter renal sympathetic denervation despite angiographically significant proximal stenosis: Proof of concept from a case report

Transcatheter renal sympathetic denervation, which encompasses percutaneous radiofrequency ablation of nervous fibers surrounding the renal arteries, has been recently shown effective and safe in patients with resistant hypertension, i.e. those not achieving adequate blood pressure control despite being on several anti-hypertensive agents at maximum tolerated dosage [1–3]. Pivotal trials have however excluded to date several patients, including those with significant renal artery stenosis or previous renal artery intervention.

Renal artery stenosis: Up-date on diagnosis and treatment

Significant renal artery stenosis (RAS) can cause or result in deterioration of arterial hypertension and may promote the development of renal insufficiency. The activation of the renin-angiotensin-aldosterone system results in structural heart disease and may impact patient survival. Technical improvements of diagnostic and interventional endovascular tools have led to a more widespread use of endoluminal renal artery revascularization and extension of the indications for this type of therapy during the past two decades. Whereas balloon angioplasty is still the method of choice for the treatment of fibromuscular dysplasia, stent implantation is indicated in ostial atherosclerotic RAS. However, none of the so far published or presented randomized controlled trials could prove a beneficial outcome of RAS revascularization compared to medical management. As a result of these negative trials including the largest published trial to date, the ASTRAL trial, referrals to endovascular renal artery revascularization have declined and, moreover, reimbursement of these procedures has become a matter of debate. Crucial for a clinical benefit following revascularization of RAS is proper patient selection, revascularization being only indicated after proof of hemodynamic relevance of RAS. This article summarizes the appropriate diagnostic work-up of patients with suspected RAS, discusses the limitations of the results published so far and their impact on the indication for RAS revascularization.

Utility of color doppler ultrasound in the evaluation of renal artery stenosis in comparison with contrast-enhanced magnetic resonance angiography

Renal artery stenosis (RAS) is one of the main correctable causes of secondary systemic arterial hypertension. Color Doppler ultrasound (DUS), a non-invasive imaging modality, has been used to diagnose RAS in hypertensive patients. This study was conducted in the period between June 2008 and March 2010 to compare the sensitivity, specificity, accuracy and predictive values of DUS using contrast-enhanced magnetic resonance angiography (CEMRA) as the gold standard for the diagnosis of RAS. Fifty-seven consecutive patients with clinical findings suggestive of RAS (32 males and 25 females) with a mean age of 56 years (±7.92 years) were referred to the University Kebangsaan Medical Center to be screened for RAS using DUS and CEMRA. RAS was considered significant if the reduction in diameter was >60%. A total of 114 arteries were assessed, 65 in males (57%) and 49 in females (43%). On DUS, the parameters measured were the peak systolic velocity at the proximal main renal artery (PSV-P), distal main renal artery (PSV-D) and the suprarenal aorta (PSV-A) at the level of the renal hila and the acceleration time (AT) at the main renal artery. The renal-renal ratio (RRR), which is the value of PSV-P/PSV-D, and the renal-aortic ratio (RAR), which is the value of PSV-P/PSV-A, were then calculated. The accuracy, sensitivity, specificity and positive and negative predictive values of DUS in the detection of significant RAS were determined. All measured DUS parameters were positive for the detection of RAS, with an accuracy of 98.3%. On retrospective review, all the arteries that showed significant stenosis on CEMRA demonstrated an irregular outline on DUS. We conclude that DUS is accurate in the diagnosis of significant RAS but is not very sensitive as a screening tool.

Co-Existence of Carotid Artery Disease, Renal Artery Stenosis, and Lower Extremity Peripheral Arterial Disease in Patients With Coronary Artery Disease

In atherosclerosis, carotid artery stenosis (CAS), renal artery stenosis (RAS), lower extremity peripheral arterial disease (PAD), and coronary artery disease (CAD) are common pathologic lesions; their interrelationship is, however, unclear. We studied concomitant multiple atherosclerotic lesions in patients with CAD to understand their prevalence and relations. A cross-sectional analysis was performed on data from consecutive patients who underwent nonemergent coronary angiography. Simultaneous carotid and renal artery Doppler studies and ankle-brachial systolic pressure measurements were reviewed to diagnose concomitant lesions and their severity. The study included 1,734 patients (aged 71 ± 9 years; 70% men), with prevalences of CAS, RAS, lower extremity PAD, and CAD of 6%, 7%, 13%, and 72%, respectively. In patients with CAD (n = 1,253), the prevalences of CAS, RAS, and lower extremity PAD were 7%, 9%, and 16%, respectively; 24% CAD patients had ≥1 additional atherosclerotic lesion. Significant interactions among the prevalences of these lesions were found. In addition, the extent of CAD and the prevalences of CAS, RAS, and lower extremity PAD were significantly correlated. Multivariate analysis supported these relationships. In conclusion, the prevalences of CAS, RAS, lower extremity PAD, and CAD were strongly interrelated in the study population; CAD severity was related to that of other atherosclerotic lesions. Additional systematic screening of other concomitant atherosclerotic lesions is recommended, especially in CAD patients having multivessel disease, left main disease, and/or already diagnosed with other concomitant atherosclerotic lesions.

Green Tagging in Displaying Color Doppler Aliasing: A Comparison to Standard Color Mapping in Renal Artery Stenosis

To quantitatively assess the contrast-to-noise ratio (CNR) of green tagging and standard color flow images in displaying fast flow velocity, we retrospectively reviewed 20 cases of hemodynamically significant renal artery stenosis (RAS) detected by renal color Doppler ultrasound and confirmed with digital subtraction angiography. At the site of RAS, blood flow with high velocity that appeared as aliasing on color flow images was computationally analyzed with both green tagging and standard color mapping. To assess the difference in the CNR between normal background flow and the aliased signal as a function of visualizing aliasing between the two color mappings, we used GetColorpixels (Chongqing Medical University, Chongqing, China) to count the values in the color channels after segmenting color pixels from gray-scale pixels. We then calculated the CNR in each color channel-red, green, and blue (RGB)--in the aliasing region on green tagging and standard color mapping. The CNRs in the red, green and blue channels were 0.35 ± 0.44, 1.11 ± 0.41 and 0.51 ± 0.19, respectively, on standard color mapping, and 0.97 ± 0.80, 4.01 ± 1.36 and 0.64 ± 0.29, respectively, on green tagging. We used a single-factor analysis of variance and two-tailed t-test to assess the difference in CNR in each color channel between the two color mappings at the site of RAS. With these comparisons, there was no significant difference in the CNR in the red or blue channel between green tagging and standard color mapping (p > 0.05). However, there was a statistically significant difference in the CNR in the green channel between the two color mappings (p = 0.00019). Furthermore, the CNR measured in the green channel on the green tagging image was significantly higher than the CNRs in all other color channels on both color mapping images (p = 0.000). Hence, we conclude that green tagging has significantly higher visibility as a function of high-velocity flow than standard color mapping. The use of green tagging may improve the ability to detect RAS with color Doppler ultrasound.

Have We New Therapeutic Strategies in the Treatment of Renovascular Nephropathy?

Renal artery stenosis (RAS) is a cause of hypertension and ischemic nephropathy. The incidence of this disorder is probably less than 1% in patients with mild hypertension, but rises to as high as 10 to 40% in patients with acute, severe or refractory hypertension. Significant RAS can be caused by atheromatous plaques, or due to fibromuscular dysplasia (FMD). Atherosclerotic lesions are present in almost 7% of adults older than 65 years and up to 50% of patients presenting with diffuse atherosclerotic disease. In contrast to atherosclerosis, FMD most often affects women under the age of 50 and typically involves the distal main renal artery or the intrarenal branches. The optimal treatment for RAS is not yet established. Based on recent trials, we reviewed the literature on pharmacological and endovascular treatment of atherosclerotic RAS and ischemic nephropathy.

Reversal of Cardiogenic Shock After Bilateral Renal Artery Stenting

Renal artery stenosis, which can occur with atherosclerotic disease or fibromuscular dysplasia, is estimated to be present in 25%-34% of patients undergoing cardiac catheterization. Evidence is still developing to better understand the clinical significance of renal artery stenosis and its pathophysiologic interplay with cardiovascular disease. We present a case of cardiogenic shock with dramatic improvement after bilateral renal artery stenting.

Prevalence and predictors of renal artery stenosis in patients undergoing peripheral and coronary angiography

Renal artery stenosis is a potential cause of secondary hypertension, ischemic nephropathy and end-stage renal disease. Atherosclerosis is by far the most common etiology of renal artery stenosis in elderly. We investigated whether the presence of significant atherosclerotic renal artery stenosis (ARAS) with luminal diameter narrowing ≥50 % could be predicted in patients undergoing peripheral and coronary angiography. The records of 3,500 consecutive patients undergoing simultaneous renal angiography along with peripheral and coronary angiography were reviewed. The patients with known renal artery disease were excluded. Prevalence of ARAS was 5.7 %. Significant ARAS (luminal diameter narrowing ≥50 %) was present in 139 patients (3.9 %). Hypertension with altered serum creatinine and triple-vessel CAD were associated with significant renal artery stenosis in multivariate analysis. No significant relationship between the involved coronary arteries like left anterior descending, left circumflex, right coronary artery and ARAS was found. Only hypertension and altered serum creatinine were associated with bilateral ARAS. Extent of CAD or risk factors like diabetes, hyperlipidemia or smoking did not predict the unilateral or bilateral ARAS. Prevalence of ARAS among the patients in routine cardiac catheterization was 5.7 %. Hypertension is closely associated with significant ARAS. Significant CAD in the form of triple-vessel disease and altered renal function tests are closely associated with ARAS. They predict the presence of significant renal artery stenosis in patients undergoing routine peripheral and coronary angiography. Moreover, hypertension and altered renal functions predict bilateral ARAS.