Guidelines for the Reporting of Renal Artery Revascularization in Clinical Trials

Role of drug-eluting stent on Takayasu arteritis with renal artery stenosis

Takayasu arteritis (TA) is defined as granulomatous inflammation of large arteries involving the aorta and its primary branches. Takayasu arteritis with renal artery stenosis (TARAS) is a common cause of pediatric renovascular hypertension. The main purposes of TARAS management are to improve high blood pressure and recover renal function. When general medication fails to improve symptoms, renal revascularization may be attempted.  Implantation of a drug-eluting stent (DES) has been used as an alternative strategy for pediatric renal revascularization. Here, we report on a 10-year-old, female, Javanese patient with bilateral TARAS who underwent DES implantation. Her clinical presentation was hypertensive crisis and worsened renal function. Bilateral renal artery DES implantation was performed successfully without complications. The child’s blood pressure was controlled using two anti-hypertensive medications after DES implantation and her renal function recovered. Dual anti-platelet therapy was given to minimize the risk of stent thrombosis.

Validation of computed tomography angiography as a complementary test in the assessment of renal artery stenosis: a comparison with digital subtraction angiography

BACKGROUND

Renal artery stenosis is an important cause of hypertension in children, accounting for 5-10% of cases. When suspected, noninvasive imaging options include ultrasound (US), computed tomography (CT) angiography and magnetic resonance (MR) angiography. However, digital subtraction angiography (DSA) remains the gold standard.

OBJECTIVE

To investigate the accuracy and inter-reader reliability of CT angiography in children with suspected renal artery stenosis.

MATERIALS AND METHODS

This is a retrospective study of patients suspected of having renal artery stenosis evaluated by both CT angiography and DSA between 2008 and 2019 at a tertiary pediatric hospital. Only children who underwent CT angiography within 6 months before DSA were included. CT angiography studies were individually reviewed by two pediatric radiologists, blinded to clinical data, other studies and each other's evaluation, to determine the presence of stenosis at the main renal artery and 2nd- and 3rd-order branches. The sensitivity, specificity and accuracy were calculated using DSA as the reference. The effective radiation dose for CT angiography and DSA was also calculated. Kappa statistics were used to assess inter-reader agreement.

RESULTS

Seventy-four renal units were evaluated (18 girls, 19 boys). The patients' median age was 8 years (range: 1-21 years). Overall, CT angiography was effective in detecting renal artery stenosis with a sensitivity of 85.7%, specificity of 91.5% and accuracy of 88.9%. There was moderate inter-reader agreement at the main renal artery level (k=0.73) and almost perfect inter-reader agreement at the 2nd/3rd order (k=0.98). However, the sensitivity at the 2nd- and 3rd-order level was lower (14.3%). CT angiography provided excellent negative predictive value for evaluating renal artery stenosis at the main renal artery level (90.1%) and at the 2nd- or 3rd-order branches (82.7%). The median effective dose of CT angiography studies was 2.2 mSv (range: 0.6-6.3) while the effective dose of DSA was 13.7 mSv.

CONCLUSION

CT angiography has high sensitivity and specificity at the main renal artery level with a lower radiation dose than previously assumed. Therefore, it can be used as a diagnostic tool in patients with low to medium risk of renal artery stenosis, and as a screening and treatment planning tool in patients at high risk.

Adherence to the RIGHT statement in Society of Interventional Radiology guidelines

Context

The Reporting Items for Practice Guidelines in Health Care (RIGHT) Statement was developed by a multidisciplinary team of experts to improve reporting quality and transparency in clinical practice guideline development.

Objective

To assess the quality of reporting in clinical practice guidelines put forth by the Society of Interventional Radiology (SIR) and their adherence to the RIGHT statement checklist.

Methods

In March 2018, using the 22 criteria listed in the RIGHT statement, two researchers independently documented adherence to each item for all eligible guidelines listed by the SIR by reading through each guideline and using the RIGHT statement elaboration and explanation document as a guide to determine if each item was appropriately addressed as listed in the checklist. To qualify for inclusion in this study, each guideline must have met the strict definition for a clinical practice guideline as set forth by the National Institute of Health and the Institute of Medicine, meaning they were informed by a systematic review of evidence and intended to direct patient care and physician decisions. Guidelines were excluded if they were identified as consensus statements, position statements, reporting standards, and training standards or guidelines. After exclusion criteria were applied, the two researchers scored each of the remaining clinical practice guidelines (CPGs) using a prespecified abstraction Google form that reflected the RIGHT statement checklist (22 criteria; 35 items inclusive of subset questions). Each item on the abstraction form consisted of a “yes/no” option; each item on the RIGHT checklist was recorded as “yes” if it was included in the guideline and “no” if it was not. Each checklist item was weighed equally. Partial adherence to checklist items was recorded as “no.” Data were extracted into Microsoft Excel (Microsoft Corporation) for statistical analysis.

Results

The initial search results yielded 129 CPGs in the following areas: 13 of the guidelines were in the field of interventional oncology; 16 in neurovascular disorders; five in nonvascular interventions; four in pediatrics; 25 in peripheral, arterial, and aortic disease; one in cardiac; one in portal and mesenteric vascular disease; 37 in practice development and safety; three in spine and musculoskeletal disorders; 14 in venous disease; five in renal failure/hemodialysis; and five in women’s health. Of the 46 guidelines deemed eligible for evaluation by the RIGHT checklist, 12 of the checklist items showed less than 25% adherence and 13 showed more than 75% adherence. Of 35 individual RIGHT statement checklist items, adherence was found for a mean (SD) of 22.9 items (16.3). The median number of items with adherence was 21 (interquartile range, 7.5–38).

Conclusion

The quality of reporting in interventional radiology guidelines is lacking in several key areas, including whether patient preferences were considered, whether costs and resources were considered, the strength of the recommendations, and the certainty of the body of evidence. Poor adherence to the RIGHT statement checklist in these guidelines reveals many areas for improvement in guideline reporting.

Diagnosis and Treatment of Renal Artery Stenosis in China in the Era of Donation After Cardiac Death

Background

The aim of this study was to investigate the clinical features and treatment strategies of transplant renal artery stenosis (TRAS) with kidneys from donation after cardiac death (DCD).

Material/Methods

We collected the clinical data of donors and recipients of single-center DCD-induced TRAS from January 2015 to June 2017.

Results

All the 8 cases of TRAS were from hypertensive cerebrovascular accident DCD-originated kidneys. The mean donor age was 53.5 (45~57) years, with mean BMI 27.8 (26.4~32.3) kg/m², atherosclerosis index 5.8 (4.9~7.0), and renal atherosclerotic plaque. Clinical features of TRAS were: refractory hypertension with elevated serum creatinine >50%, and negative urine protein and occult blood. Ultrasound of transplanted kidneys showed renal blood flow index 0.49 (0.43~0.55). Angiography confirmed the diagnosis of renal artery trunk or secondary branch stenosis. There were 2 cases of moderate stenosis and 6 cases of severe stenosis. Six patients underwent stent implantation and 2 patients underwent balloon dilatation. Seven patients had serum creatinine recovery after interventional therapy during follow-up. The transplanted kidney of 1 patient ruptured 6 h after interventional therapy and was then resected.

Conclusions

The incidence of TRAS with hypertensive cerebrovascular accident DCD-originated kidneys is relatively high, which is a warning to kidney transplant physicians. Digital subtraction angiography (DSA) is the most reliable diagnostic means of TRAS and can be performed concurrently with intervention therapy. If the donor has severe atherosclerosis, plaques that are visible to the unaided eye in the renal artery trunk should be removed as completely as possible.

Endovascular Management of Neurofibromatosis Type I-Associated Vasculopathy: A Case Series and Brief Review of the Literature

Purpose:

Neurofibromatosis type 1 (NF1) is an autosomal-dominant disorder found in approximately 1 of every 3000 individuals. Neurofibromatosis type 1 can have vascular manifestations including aneurysms, stenoses, and arteriovenous malformations. The purpose of this article is to describe the clinical manifestations of NF1 vasculopathy, discuss therapeutic options, and highlight endovascular therapies from our institutional experience.

Materials and Methods:

The radiology information system was searched for cases of NF1. Cases with vasculopathy managed with endovascular therapies were included. Demographics, clinical histories, procedural details, and outcomes were recorded. A review of the literature for the management strategies of NF1 vasculopathy was performed.

Results:

Two pediatric patients with NF1 were identified, both of whom presented with hypertension found to be secondary to renal artery stenosis. One of the patients also had infrarenal aortic narrowing. Both patients were successfully treated with balloon angioplasty, resulting in improved blood pressures. The review of the literature identified case series of pharmacologic, surgical, and endovascular therapies, although, endovascular therapies appear to be preferred due to lower morbidity and mortality.

Conclusions:

NF1 vasculopathy is a rare condition that most often presents with hypertension due to renal artery stenosis. In these situations, endovascular management is the preferred approach.

Renal artery stenting for atherosclerotic renal artery stenosis identified in patients with coronary artery disease: Does captopril renal scintigraphy predict outcomes?

The authors evaluated the effectiveness of percutaneous renal revascularization (PRR) with stenting for the treatment of atherosclerotic renal artery stenosis (ARAS) in patients with coronary artery disease and the usefulness of captopril renal scintigraphy for predicting clinical outcomes after PRR. Sixty-four consecutive patients, referred for evaluation of suspected ARAS, after coronary angiography, underwent baseline captopril renal scintigraphy followed by renal angiography. Forty-four patients (68.7%) were diagnosed with a significant ARAS≥ 60% and were treated with PRR plus medical therapy. Twenty-four months after PRR, 86.4% and 73.3% of patients showed a hypertension and renal benefit, respectively. Captopril renal scintigraphy positivity had moderate sensitivity and high specificity in predicting a hypertension and renal benefit. In patients with ARAS≥ 70%, the sensitivity and specificity were 100% for both a hypertension and renal benefit.PRR for ARAS conferred a substantial benefit in patients with a high coronary artery disease burden. Captopril renal scintigraphy was highly accurate in predicting clinical outcomes.

Treatment of severe hypertension in a 14-year-old child: Successful blood pressure control with additive administration of captopril, an angiotensin-converting enzyme inhibitor, in a patient with bilateral renovascular hypertension

We report a 14-year-old boy with recurrent episodes of headache caused by uncontrolled hypertension. The diagnosis of renovascular hypertension due to Takaysu arteritis (TA) was made based on an increase in erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) and computed tomography (CT) image of bilateral renal artery stenosis was taken. Renal scintigraphy revealed normal perfusion and function of the right kidney and severe reduction of the perfusion and function of the left kidney. Careful drug adjustments significantly improved but did not fully control the blood pressure (BP); further, angioplasty, which showed almost occlusion of the left renal artery opening and the minor narrowing of the right renal artery, failed to regain sufficient BP control. The addition of captopril, an angiotensin-converting enzyme (ACE) inhibitor, to conventional antihypertensive drugs successfully and safely lowered BP and preserved the renal function. This unique case suggested that ACE inhibitors achieved better control of BP in a patient with bilateral renal stenosis and that the patient may have hemodynamically significant stenosis caused by unilateral renal artery.

Outcomes of percutaneous transluminal angioplasty for pediatric renovascular hypertension

BACKGROUND

Up to 10% of hypertensive children will have renovascular disease. Where medical therapy fails to control the hypertension, endovascular techniques can improve renal perfusion. The purpose of this study was to assess the efficacy of angioplasty in controlling renovascular hypertension (RVH) in children.

METHODS

This is a single-center, retrospective review of patients who underwent angioplasty for RVH between 1992 and 2009. All patients were selected from the Interventional Radiology database. The primary outcome measure was clinical success as reflected by a favorable, sustained response in blood pressure for at least 1year following the angioplasty.

RESULTS

Two hundred sixteen patients underwent diagnostic angiography for suspected RVH, of these 28 required 42 angioplasties. Ten (36%) were cured, 9 (32%) were improved and 9 (32%) failed to respond to treatment. Major complications occurred in three patients and minor complications occurred in 18 angioplasties. Fibromuscular dysplasia (FMD) was the most common diagnosis in this series and was associated with a 79% success rate.

CONCLUSION

In our exclusively pediatric population angioplasty safely improved blood pressure control in 68% of patients, more than half of which are cured. FMD appeared to have the best clinical outcomes in our series.

Cutting Balloon Angioplasty (CBA) for the Treatment of Renal Artery Fibromuscular Dysplasia (FMD) in Six Patients: 5-Year Long-Term Results

PURPOSE

To evaluate long-term outcomes in terms of hypertension control, recurrent stenosis, and reinterventions from patients who underwent cutting balloon angioplasty (CBA) for symptomatic renal artery fibromuscular dysplasia (FMD).

MATERIALS AND METHODS

From 2011, six consecutive renal artery FMD women underwent CBA for poorly controlled hypertension, despite antihypertensive therapy. Follow-up consisted of blood pressure monitoring and duplex ultrasonography at 1, 6, and 12 months and thereafter annually for 5 years.

RESULTS

All treatments were technically successful. Recurrence of hypertension was found in two patients within 12 months, and reinterventions were performed using CBA.

CONCLUSION

Results show the efficacy of CBA for renal artery FMD.

Interventional Therapy for Transplant Renal Artery Stenosis Is Safe and Effective in Preserving Allograft Function and Improving Hypertension

Purpose:

To evaluate the outcomes of percutaneous intervention (PI) for transplant renal artery stenosis (TRAS).

Materials and Methods:

Doppler ultrasonography was used as the screening tool, and angiography was the diagnostic method for TRAS. The indications for PI were (1) a reduction in lumen diameter of >50% or (2) a mean pressure gradient of >15 mm Hg. Technical success was assessed immediately after the procedure. The short-term results of stenosis were evaluated by serum creatinine (Scr) levels and blood pressure (BP). The long-term results were assessed by graft survival and renal function.

Results:

From October 2009 to July 2015, a total of 660 patients had kidney transplantation and 22 cases underwent PI. The technical success was 100%. The mean Scr level preintervention was 321.6 ± 167.2 (range, 171.3-862.0) μmol/L, and it decreased to 145.3 ± 44.7 (range, 74.3-260.8) μmol/L 1 month postintervention ( P < .001). Blood pressure was also improved at 1 month postintervention, as assessed by systolic (157.0 ± 13.0 vs 131.0 ± 11.0 mm Hg, P < .001), diastolic (95.0 ± 5.0 vs 77.0 ± 9.0 mm Hg, P < .001), and mean arterial pressure (116.0 ± 7.0 vs 95.0 ± 9.0 mm Hg, P < .001). The patency rate was 100%, 91.7%, and 85.7% at 1, 3, and 12 months, respectively. The secondary patency rate was 100%. Graft survival was 100% during follow-up. There was no significant deterioration in graft function or BP ( P > .05) postintervention when compared to posttransplantation.

Conclusions:

Percutaneous intervention for TRAS is safe and results in significant improvement both in allograft function and in BP.

Use of Gadolinium-Based Angiography for Renal Artery Stenting in a Patient With Renal Insufficiency

The number of percutaneous diagnostic and interventional procedures performed continues to increase. Despite the use of various methods to reduce the incidence of contrast-induced nephropathy, the development of renal failure remains a significant problem with iodinatedbased contrast agents. Patients with a baseline renal insufficiency are at considerably higher risk of permanent renal deterioration following exposure to iodinated contrast. The authors report a successful case of percutaneous stenting of the renal artery using a gadolinium-based contrast agent in a high-risk patient with renal insufficiency.

Renal Transplant Arterial Stenosis Treated With Bare-Metal Versus Drug-Eluting Stents: Comparison of Treatment Outcomes

INTRODUCTION

This study aims to evaluate outcomes of bare-metal stents (BMS) versus drug-eluting stents (DES) in patients who undergo stenting for transplant renal arterial stenosis.

MATERIALS AND METHODS

We retrospectively reviewed records of renal transplantation patients who underwent transplant renal arterial stenting from September 2009 to September 2013. All stents greater than 5 mm were excluded to allow for equivalent comparison between the DES and BMS groups. Statistical comparisons were performed using a two-tailed Fischer exact test, and analysis of continuous variables was analyzed using a one-way analysis of variance.

RESULTS

The final study population included a total of 18 patients who received either BMS or DES (11 and 7 patients, respectively) for transplant renal arterial stenosis. The most common indications for stenting were increasing creatinine level and abnormal Doppler velocities. There were more re-interventions with BMS (n = 4/11) than DES (n = 0/7), but the trend was not statistically significant (P = .12). Three patients who received BMS had a clinically significant decrease in blood pressure versus 4 in the DES group (P = .33). Six patients who received BMS had a clinically significant decrease in creatinine level versus 3 in the DES group (P = 1.0).

CONCLUSION

There is an absolute but not statistically significant difference in the incidence of restenosis requiring repeat intervention between the BMS and DES groups. No difference was detected in clinical success as measured by decreases in blood pressure or creatinine. Future larger studies are needed to corroborate these findings.

Sirolimus-Eluting versus Bare-Metal Low-Profile Stent for Renal Artery Treatment (GREAT Trial): Angiographic Follow-up after 6 Months and Clinical Outcome up to 2 Years

Purpose:

To evaluate the patency of sirolimus-eluting stents (SES) compared to bare-metal stents (BMS) in the treatment of atherosclerotic renal artery stenosis (RAS).

Methods:

Between November 2001 to June 2003, 105 consecutive symptomatic patients (53 men; mean age 65.7 years) with RAS were treated with either a bare-metal (n=52) or a drug-eluting (n=53) low-profile Palmaz-Genesis peripheral stent at 11 centers in a prospective nonrandomized trial. The primary endpoint was the angiographic result at 6 months measured with quantitative vessel analysis by an independent core laboratory. Secondary endpoints were technical and procedural success, clinical patency [no target lesion revascularization (TLR)], blood pressure and antihypertensive drug use, worsening of renal function, and no major adverse events at 1, 6, 12, and 24 months.

Results:

At 6 months, the overall in-stent diameter stenosis for BMS was 23.9%±22.9% versus 18.7%±15.6% for SES (p=0.39). The binary restenosis rate was 6.7% for SES versus 14.6% for the BMS (p=0.30). After 6 months and 1 year, TLR rate was 7.7% and 11.5%, respectively, in the BMS group versus 1.9% at both time points in the SES group (p=0.21). This rate remained stable up to the 2-year follow-up but did not reach significance due to the small sample. Even as early as 6 months, both types of stents significantly improved blood pressure and reduced antihypertensive medication compared to baseline (p<0.01). After 6 months, renal function worsened in 4.6% of the BMS patients and in 6.9% of the SES group. The rate of major adverse events was 23.7% for the BMS group and 26.8% for the SES at 2 years (p=0.80).

Conclusion:

The angiographic outcome at 6 months did not show a significant difference between BMS and SES. Renal artery stenting with both stents significantly improved blood pressure. Future studies with a larger patient population and longer angiographic follow-up are warranted to determine if there is a significant benefit of drug-eluting stents in treating ostial renal artery stenosis.

Multimarker assessment for the prediction of renal function improvement after percutaneous revascularization for renal artery stenosis

BACKGROUND

Identifying patients likely to have improved renal function after percutaneous transluminal renal angioplasty and stenting (PTRA) for renal artery stenosis (RAS) is challenging. The purpose of this study was to use a comprehensive multimarker assessment to identify those patients who would benefit most from correction of RAS.

METHODS

In 127 patients with RAS and decreased renal function and/or hypertension referred for PTRA, quantification of hemodynamic cardiac stress using B-type natriuretic peptide (BNP), renal function using estimated glomerular filtration rate (eGFR), parenchymal renal damage using resistance index (RI), and systemic inflammation using C-reactive protein (CRP) were performed before intervention.

RESULTS

Predefined renal function improvement (increase in eGFR ≥10%) at 6 months occurred in 37% of patients. Prognostic accuracy as quantified by the area under the receiver-operating characteristics curve for the ability of BNP, eGFR, RI and CRP to predict renal function improvement were 0.59 (95% CI, 0.48-0.70), 0.71 (95% CI, 0.61-0.81), 0.52 (95% CI, 0.41-0.65), and 0.56 (95% CI, 0.44-0.68), respectively. None of the possible combinations increased the accuracy provided by eGFR (lower eGFR indicated a higher likelihood for eGFR improvement after PTRA, P=ns for all). In the subgroup of 56 patients with pre-interventional eGFR <60 mL/min/1.73 m(2), similar findings were obtained.

CONCLUSIONS

Quantification of renal function, but not any other pathophysiologic signal, provides at least moderate accuracy in the identification of patients with RAS in whom PTRA will improve renal function.

Clinical efficacy of percutaneous transluminal renal artery stenting for the treatment of renovascular hypertension associated with Takayasu arteritis

BACKGROUND

This study aims to observe and analyze the clinical efficacy of interventional therapy for patients with Takayasu arteritis (TA) experiencing renovascular hypertension (RH).

METHODS

Eight TA patients with RH underwent percutaneous transluminal renal artery stenting (PTRAS). Patients were followed up 1, 6, 12, and 24 months postoperatively for levels of blood pressure, number of antihypertensive drugs being taken, levels of serum creatinine, and the presence of renal artery restenosis.

RESULTS

All 8 patients were successfully followed up 1, 6, and 12 months postoperatively, but 1 was lost to follow-up at 24 months. All patients had significantly lower average blood pressure levels compared with those at baseline (P < 0.05); treatment efficacy rates (recovery or improvement) at 1, 6, 12, and 24 months were 94%, 90%, 80%, and 80%, respectively. The average number of antihypertensive drugs being taken was 3.5 at baseline, 1.0 at 1 month, 0.5 at 6 months, 1.0 at 12 months, and 1.5 at 24 months. Serum creatinine levels during the follow-up period were not significantly different from those at the baseline. No patient developed renal artery restenosis during the follow-up period.

CONCLUSIONS

PTRAS is a safe and effective treatment for TA-associated RH, with a high technical success rate and a low complication rate. This interventional therapy can effectively control TA-related hypertension and can also preserve and even improve kidney function.

Changes in the clinical manifestations of primary aldosteronism

BACKGROUND/AIMS

Primary aldosteronism (PA) is now widely recognized to have a higher prevalence than was once thought. In view of its increasing prevalence, we compared chronological changes in clinical manifestations of PA according to different times of diagnosis.

METHODS

In total, 85 patients diagnosed with PA from January 1986 through March 2012 were reviewed retrospectively, based on their medical records. During two periods-1986 to 2005 and 2006 to 2012-41 and 44 patients, respectively, were diagnosed with PA. We compared the clinical and biological characteristics of PA between these periods.

RESULTS

The results demonstrate an increasing trend in the prevalence of idiopathic hyperaldosteronism (IHA; p = 0.19). In the 2006 to 2012 period, patients with PA presented with higher serum potassium levels at the time of diagnosis than in the 1986 to 2005 period (p < 0.0002). Adrenal vein sampling (AVS) was performed mostly in the latter period (82.3%) and the diagnostic accuracy of adrenal computed tomography, compared with AVS, was only 56.2%. About 78.0% versus 86.3% of patients had at least one target organ damage (TOD) in the 1986 to 2005 and 2006 to 2012 periods, respectively (p = 0.39). However, patients with TOD were older and had longer durations of hypertension than patients without, in both periods.

CONCLUSIONS

PA is becoming more prevalent. There was an increasing tendency for IHA, and more PA patients presented with normokalemia than in the earlier period. Early and accurate diagnosis of PA with AVS and proper treatment should have substantial prognostic value.

An analysis of the factors influencing radiation dose and fluoroscopic time during renal artery stent placement

PURPOSE

To determine the factors that affect mean absorbed dose and fluoroscopic times during renal artery stent placement.

MATERIALS AND METHODS

After institutional review board approval, the HI-IQ database was queried for patients undergoing renal artery stent placement only from January 2007 to June 2010. Procedures that were performed as part of other procedures such as iliac artery stents were excluded. The HI-IQ data included fluoroscopy time (f) and radiation dose (mGy). Demographic, medical history, procedural details, and advanced preprocedural renal artery stent imaging were obtained. Variables (number of stents, average body mass index , number of stents placed per year and number of years' service of an interventional physician, pre-procedural imaging, and use of embolic protection device) were analyzed using a t test after log transformation and testing for variance with an F test.

RESULTS

A total of 134 patients (75 males, 70.6 ± 10.5 years old) underwent the placement of 177 renal artery stents (unilateral [n = 95], average stent per patient = 1.3). Mean fluoroscopy time was 15.6 minutes and mean absorbed dose to the patient was 1729 mGy. The average fluoroscopic time and absorbed dose was significantly higher with bilateral stent placement compared to unilateral placement (13.8 vs 19.7 minutes, P = .002; 1803 vs 2380 mGy, P = .03). The average fluoroscopic time was significantly higher in patients undergoing abdominal aortogram prior to renal artery selection and stent placement.

CONCLUSION

The placement of more than 1 stent with an abdominal angiogram prior to renal artery stent placement results in increased fluoroscopic time and mean absorbed dose.

Treatment of atheromatous renal artery in-stent restenosis in 51 patients

OBJECTIVE

To evaluate our treatment of renal artery in-stent restenosis.

PATIENTS AND METHODS

Monocentric retrospective study of 53 cases of restenosis and two occlusions in 51 patients detected via systematic follow-up with imaging (72.5%) and/or deterioration of kidney function (5.9%) and/or blood pressure failure (54.9%), 15.7 months (5-121) after implantation, giving rise to 49 recalibrations via a balloon and five additional stentings. Analysis of the technical results, the effects on blood pressure and kidney function after repeated revascularizations.

RESULTS

Secondary permeability of 38 arteries (63.2%) after 12.4 months (3-64) with 14 second restenoses; 33.3% after redilation with a balloon, 60% after renewed stenting, more common in smokers (P=0.02), in case of peripheral arterial disease (P=0.02), ostial location (P=0.049) and kidney function impairment at the time of diagnosis of the restenosis (P=0.012). After 12.7 months (3-64) post-revascularization, kidney function was improved in 30% of patients and stabilised in 50% of patients. Treatment of second restenoses: one failure (7.1%), nine dilations with a balloon, three cutting balloon, one second stent. Treatment of third restenoses: 71.4% treated with a balloon (2), cutting balloon (2) or coated stent (DES) (1); then permeability at a later point in time: 50%.

CONCLUSION

The treatment of repeated restenoses with conventional techniques is of imperfect efficacy, and currently remains un-codified.

Critical limb ischemia: advanced medical therapy

Systemic atherosclerosis and its risk factors are present in the majority of patients with critical limb ischemia. Aggressive medical therapy is an immediate and necessary part of the work-up and management of these patients and will involve a multidisciplinary approach. Risk stratification based on a patient's current clinical cardiovascular condition is important in determining the most appropriate and safe intervention and will allow both the patient and physician to make an informed decision regarding risk- and cost-benefits of treatment.

Clinical outcomes in patients with renal artery stenosis treated with stent placement with embolic protection compared with those treated with stent alone

PURPOSE

To compare the clinical outcomes in patients with chronic renal insufficiency (CRI) and renal artery stenosis (RAS) following renal artery (RA) stent placement with and without embolic protection device (EPD) usage.

MATERIALS AND METHODS

Eighteen patients who had RA stent placement with EPD were matched to control patients (RA stent only). Blood pressure, number of hypertensive medications, and estimated glomerular filtration rate (eGFR) at 3 months before the procedure and after 12 months were determined. An increase of ≥ 20% in eGFR at 12 months from baseline was defined as "improvement," decrease of ≥ 20% as "deterioration," and an eGFR change between those values as "stabilization" at 12 months.

RESULTS

At 12 months, stage 4 patients treated with EPD had significantly higher eGFR than controls (P = .01). There was no statistical difference in blood pressure outcomes between the 2 groups.

CONCLUSIONS

Patients with stage 4 CRI did significantly better with EPD than those treated without it.

Clopidogrel use before renal artery angioplasty with/without stent placement resulted in tertiary procedure risk reduction

OBJECTIVE

Contrary to coronary artery literature, the effect of preprocedural clopidogrel on renal artery restenosis (RAR) has not been characterized. This study was designed to evaluate the effect of preprocedural clopidogrel on target vessel revascularization (TVR), reintervention, and restenosis for patients who underwent recurrent renal artery angioplasty.

METHODS

A retrospective analysis of patients treated for RAR in a single tertiary center from January 1999 to December 2009 was conducted. Patients were divided into preadmission use of (1) clopidogrel or (2) aspirin only (acetylsalicylic acid [ASA]) for the initial procedure. TVR was defined as occurrence of a tertiary procedure for symptomatic RAR. Rate of freedom from event (ie, tertiary restenosis and TVR) was analyzed using Kaplan-Meier method.

RESULTS

Eighty-eight interventions were performed on 77 patients with RAR; 66% were females with average (mean ± SEM) age and body mass index of 68.8 ± 1.1 and 28.6 ± 0.8, respectively. Comorbidities included 96% chronic hypertension, 33% diabetes, 76% hyperlipidemia, 20% renal insufficiency, 39% tobacco use, 58% coronary artery disease, and 51% peripheral vascular disease. Clopidogrel use increased significantly during the index procedure from admission 35.2% to discharge 97.7% (P < .001, McNemar test). There was a trend toward risk reduction of a tertiary intervention (23%) for patients admitted on clopidogrel compared with ASA (P = .052). Likewise, there was a trend (P = .051) toward increased freedom from a tertiary intervention, with cumulative freedom at 8 years 93.5% for clopidogrel vs 61% for ASA. No differences were found for restenosis.

CONCLUSIONS

The use of preprocedural clopidogrel was associated with a possible risk reduction of TVR reintervention, but this finding needs to be validated in randomized clinical trial.

Efficacy of revascularization for renal artery stenosis caused by fibromuscular dysplasia: a systematic review and meta-analysis

In patients with fibromuscular dysplasia and renal artery stenosis, renal artery revascularization has been used to cure hypertension or to improve blood pressure control. To provide an up-to-date assessment of the benefits and risks associated with revascularization in this condition, we performed a systematic review of studies in which hypertensive patients with fibromuscular dysplasia renal artery stenosis underwent percutaneous transluminal renal angioplasty or surgical reconstruction. We assessed how often periprocedural complications and hypertension cure and improvement occurred. We selected 47 angioplasty studies (1616 patients) and 23 surgery studies (1014 patients). Combined rates of hypertension cure, defined according to the criteria in each study, after angioplasty or surgery were estimated to be 46% (95% CI: 40% to 52%) and 58% (95% CI: 53% to 62%), respectively, with substantial variations across studies. The probability of being cured was negatively associated with patient age and time of publication. Cure rates using current definitions of hypertension cure (blood pressure <140/90 mm Hg without treatment) were only 36% and 54% after angioplasty and surgery, respectively. The combined risks of periprocedural complications were 12% and 17% after angioplasty and surgery, respectively, with less major complications after angioplasty than surgery (6% versus 15%). In conclusion, angioplasty or surgical revascularization yielded moderate benefits in patients with fibromuscular dysplasia renal artery stenosis, with substantial variation across studies. The blood pressure outcome was strongly influenced by patient age.

One year clinical outcomes of renal artery stenting: the results of ODORI Registry

The safety, efficacy and long term clinical benefits of renal artery revascularization by stenting are still a matter of debate. The aim of our study was to define the safety and efficacy of renal artery stenting with the Tsunami peripheral stent (Terumo Corporation, Tokyo, Japan). The ODORI was a prospective, multicentre registry which enrolled 251 consecutive patients, (276 renal arteries) in 36 centres across Europe. The primary endpoint was acute procedural success defined as <30% residual stenosis after stent placement. Secondary endpoints included major adverse events, blood pressure control, serum creatinine level, and target lesion revascularization (TLR) at 6 and 12 months. Patients were 70 +/- 10 years old, 59% were male, 33% had diabetes, and 96% hypertension. The main indications for renal stent implantation were hypertension in 83% and renal salvage in 39%. Direct stent implantation was performed in 76% of the cases. Acute success rate was 100% with residual stenosis of 2.5 +/- 5.4%. Systolic/diastolic blood pressure decreased from a mean of 171/89 at baseline to 142/78 mmHg at 6 months (p < 0.0001 vs. baseline), and 141/80 mmHg at 12 months (p < 0.0001 vs. baseline). Mean serum creatinine concentration did not change significantly in the total population. However, there was significant improvement in the highest tercile (from 283 micromol/l at baseline to 205 and 209 micromol/l at 6 and 12 months respectively). At 12-months, rates of restenosis and TLR were 6.6 and 0.8% respectively. The 12 month cumulative rate of all major clinical adverse events was 6.4% while the rate of device or procedure related events was 2.4%. In hypertensive patients with atherosclerotic renal artery stenosis Tsunami peripheral balloon-expandable stent provides a safe revascularization strategy, with a potential beneficial impact on hypertension control and renal function in the highest risk patients.

Glomerular filtration rate measured by (51)Cr-EDTA clearance: Evaluation of captopril-induced changes in hypertensive patients with and without renal artery stenosis

INTRODUCTION

Renal artery stenosis can lead to renovascular hypertension; however, the detection of stenosis alone does not guarantee the presence of renovascular hypertension. Renovascular hypertension depends on activation of the renin-angiotensin system, which can be detected by functional tests such as captopril renal scintigraphy. A method that allows direct measurement of the baseline and post-captopril glomerular filtration rate using chromium-51 labeled ethylenediamine tetraacetic acid ((51)Cr-EDTA) could add valuable information to the investigation of hypertensive patients with renal artery stenosis. The purposes of this study were to create a protocol to measure the baseline and post-captopril glomerular filtration rate using (51)Cr-EDTA, and to verify whether changes in the glomerular filtration rate permit differentiation between hypertensive patients with and without renal artery stenosis.

METHODS

This prospective study included 41 consecutive patients with poorly controlled severe hypertension. All patients had undergone a radiological investigation of renal artery stenosis within the month prior to their inclusion. The patients were divided into two groups: patients with (n=21) and without renal artery stenosis, (n=20). In vitro glomerular filtration rate analysis ((51)Cr-EDTA) and (99m)Tc-DMSA scintigraphy were performed before and after captopril administration in all patients.

RESULTS

The mean baseline glomerular filtration rate was 48.6+/-21.8 ml/kg/1.73 m(2) in the group wuth renal artery stenosis, which was significantly lower than the GFR of 65.1+/-28.7 ml/kg/1.73m(2) in the group without renal artery stenosis (p=0.04). Captopril induced a significant reduction of the glomerular filtration rate in the group with renal artery stenosis (to 32.6+/-14.8 ml/ kg/1.73m(2), p=0.001) and an insignificant change in the group without RAS (to 62.2+/-23.6 ml/kg/1.73m(2), p=0.68). Scintigraphy with technetium-99m dimercapto-succinic acid (DMSA) did not show significant differences in differential renal function from baseline to post-captopril images in either group.

CONCLUSIONS

Captopril induced a decrease in the GFR that could be quantitatively measured with (51)Cr-EDTA. The reduction is more pronounced in hypertensive patients with RAS.

Renal artery revascularization: predictive value of kidney length and volume weighted by resistive index

OBJECTIVE

The purpose of this study was to evaluate the usefulness of renal length, volume, and resistive index measurements at Doppler ultrasound and MR angiography in predicting improvement after renal angioplasty.

MATERIALS AND METHODS

Fifty-one patients underwent Doppler ultrasound examinations and MR angiography before percutaneous transluminal renal angioplasty. Renal length, total and cortical volumes, and resistive index were calculated. Combinations of length, volume, and resistive index measurements were correlated with improvement in blood pressure and renal function after percutaneous transluminal renal angioplasty. Thresholds for improving patient selection were chosen after analysis of receiver operating characteristics curves.

RESULTS

Lower total and cortical volumes on MR angiograms and shorter kidney length on Doppler ultrasound images were found among patients with successful blood pressure control (p = 0.042, p = 0.035, and p = 0.016, respectively). Renal length measured with Doppler ultrasound and cortical volume measured with MR angiography weighted by resistive index were the best predictive factors (p = 0.004, p = 0.006). Using a threshold of renal length-resistive index product less than 7 cm, therapeutic response was predicted with a sensitivity of 87% and specificity of 50%, whereas with a threshold value of 52 mL/m(2) for cortical renal volume-resistive index product divided by body surface area, sensitivity of 86% and specificity of 50% were obtained.

CONCLUSION

Renal length and volume combined with resistive index measurements appear to be predictive of therapeutic response after percutaneous transluminal renal angioplasty.

Transradial renal stenting: why and how

Transradial vascular access for invasive procedures is gaining increasingly acceptance due to reduced access-site complications and improved patient's comfort compared with transfemoral. However, the adoption of transradial access in peripheral vascular procedures is actually limited by anatomical and technical considerations. Yet, among all the peripheral vascular districts, the renal one seems to be particularly suitable for transradial approach. In this article, we discuss the rationale for preferring the radial approach instead of femoral and review the specific technical issues related to transradial renal artery stenting (RAS).

Limitations of angiography for the assessment of renal artery stenosis and treatment implications

Renovascular hypertension due to atherosclerotic renal artery stenosis is the most common cause of secondary hypertension. Percutaneous catheter-based renal artery revascularization has been increasingly utilized for the treatment of renal artery stenosis. Renal artery stenting has a high technical success rate, but the rate of improvement in hypertension is somewhat less than expected with this technique. Misinterpretation of angiographic images may play a role in these unfavorable clinical results. We present a case in which the diagnosis of severe renal artery stenosis was not apparent by angiography. Intravascular ultrasound and translesional pressure gradient measurements during arteriography can help to determine the precise severity of stenosis and may augment the clinical results of percutaneous renal artery stent placement.

Spontaneous renal artery dissection: long-term outcomes after endovascular stent placement

PURPOSE

To report long-term clinical and morphologic results after stent placement for spontaneous renal artery dissection (SRAD).

MATERIALS AND METHODS

Between 1991 and 2006, 16 consecutive patients (13 men; mean age, 42 y +/- 12) presented with SRAD in 17 arteries. All patients had uncontrolled hypertension at the time of presentation. Nine patients had lower back pain, 10 had progressive renal insufficiency, and three had both. All patients underwent renal angiography and stent implantation. They were followed up clinically and with renal imaging.

RESULTS

Baseline blood pressure and plasma creatinine levels were 176/107 mm Hg and 142 micromol/L, respectively. Successful renal artery recanalization and stent implantation were achieved in all patients. After a mean follow-up of 8.6 years +/- 3.4, mean blood pressure was 118/78 mm Hg, with Seven patients were taking no antihypertensive medication, with five and four patients taking single or double antihypertensive agents, respectively. The most recent follow-up showed that plasma creatinine levels were normal, and imaging of the renal arteries showed no sign of restenosis or occlusion in all patients.

CONCLUSIONS

Stent implantation for symptomatic SRAD is an effective treatment in the long term and represents a safe alternative to surgery.

RADAR - A randomised, multi-centre, prospective study comparing best medical treatment versus best medical treatment plus renal artery stenting in patients with haemodynamically relevant atherosclerotic renal artery stenosis

BACKGROUND

Prospective, international, multi-centre, randomised (1:1) trial to evaluate the clinical impact of percutaneous transluminal renal artery stenting (PTRAS) on the impaired renal function measured by the estimated glomerular filtration rate (eGFR) in patients with haemodynamically significant atherosclerotic renal artery stenosis.

METHODS

Patients will be randomised to receive either PTRAS using the Dynamic Renal Stent system plus best medical treatment or best medical treatment. Renal stenting will be performed under angiographic imaging. For patients randomised to best medical treatment the degree of stenosis measured by renal duplex sonography (RDS) will be confirmed by MR angio or multi-slice CT where possible. Best medical treatment will be initiated at randomisation or post procedure (for PTRAS arm only), and adjusted as needed at all visits. Best medical treatment is defined as optimal drug therapy for control of the major risk factors (blood pressure < or = 125/80 mmHg, LDL cholesterol < or = 100 mg/dL, HbA1c < or = 6.5%). Data recordings include serum creatinine values, eGFR, brain natriuretic peptide, patients' medical history and concomitant medication, clinical events, quality of life questionnaire (SF-12v2), 24 hour ambulatory blood pressure measurement, renal artery duplex ultrasound and echocardiography. Follow-up intervals are at 2, 6, 12 and 36 months following randomisation.The primary endpoint is the difference between treatments in change of eGFR over 12 months. Major secondary endpoints are technical success, change of renal function based on the eGFR slope change between pre-treatment and post-treatment (i.e. improvement, stabilisation, failure), clinical events overall such as renal or cardiac death, stroke, myocardial infarction, hospitalisation for congestive heart failure, progressive renal insufficiency (i.e. need for dialysis), need of target vessel revascularisation or target lesion revascularisation, change in average systolic and diastolic blood pressure, change in left ventricular mass index calculated from echocardiography, difference in the size of kidney (pole to pole length) measured by renal duplex sonography, total number, drug name, drug class, daily dose, regimen and Defined Daily Dose (DDD), of anti-hypertensive drugs, and change in New York Heart Association (NYHA) classification. Approximately 30 centres in Europe and South America will enrol patients. Duration of enrolment is expected to be 12 months resulting in study duration of 48 months.

TRIAL REGISTRATION

TRIAL REGISTRATION NUMBER

NCT00640406.

Embolic protection device use in renal artery stent placement

PURPOSE

The purpose of the present study was to report safety, efficacy, and renal function outcomes with use of the GuardWire embolic protection device (EPD) in renal artery stent placement for patients with renal artery stenosis (RAS) and chronic renal insufficiency (CRI).

MATERIALS AND METHODS

This was a retrospective study of all patients with RAS and CRI treated concomitantly with a GuardWire EPD and renal artery stents from December 2002 through June 2006. Renal function was determined by calculating the estimated glomerular filtration rate (eGFR) according to the Modification of Diet in Renal Disease formula, and subjects were divided into Kidney Disease Outcomes and Quality Initiative (K-DOQI) classes based on baseline eGFR. After revascularization, an improvement from baseline of at least one K-DOQI class was defined as improvement, unchanged K-DOQI class as stabilization, and worsening of at least one K-DOQI class as deterioration.

RESULTS

There were 63 patients (54% men) with a mean age of 75.2 years +/- 7.7. The mean baseline serum creatinine level and eGFR were 1.87 mg/dL +/- 0.6 (range, 1-3.8 mg/dL) and 36.63 mL/min per 1.73 m(2) +/- 11.42 (range, 13.85-59.99 mL/min per 1.73 m(2)), respectively, and at the last clinical follow-up, the respective measurements were 1.96 mg/dL +/- 0.72 and 38.75 mL/min per 1.73 m(2) +/- 13.25 (P = not significant). Over a mean follow-up period of 16 months +/- 12, 14 patients (25%) showed improvement, 33 (58%) had stable renal function, and 10 (18%) showed deterioration. There was one GuardWire-related dissection, which was successfully treated with a stent.

CONCLUSIONS

The GuardWire EPD, used during renal artery stent placement, is safe and was associated with stabilization or improvement in kidney function in 83% of patients with RAS and CRI.

Renal artery stent placement for restoration of renal function in hemodialysis recipients with renal artery stenosis

PURPOSE

Renal artery stent placement to treat renal artery stenosis (RAS) in patients undergoing hemodialysis is not performed commonly. We present our outcomes of discontinuation of hemodialysis after treating patients with RAS by stent placement on acute (< or =30 days of hemodialysis) and chronic hemodialysis (>30 days).

MATERIALS AND METHODS

A retrospective study was conducted in 16 patients (nine men) with an average age of 74.6 years +/- 10.6 (range, 49-86 y) who underwent treatment of 22 RAS for acute renal failure (n = 8) or uncontrolled hypertension with chronic hemodialysis (n = 8). The average follow-up was 448 days +/- 450 (median, 363.5 d; range, 6-1,583 d). The primary outcome consisted of discontinuation of hemodialysis, death, and transplantation. Secondary endpoints included restenosis, changes in blood pressure (and use of medications), and estimated glomerular filtration rate (eGFR).

RESULTS

After the stent procedure, eight patients were able to discontinue hemodialysis and remained free from dialysis over a mean period of 564 days +/- 533. The predictors of discontinuation of hemodialysis were 24-hour proteinuria, eGFR before renal artery stent placement, and size of the kidney on ultrasound studies (P < .05 for all three). There was no difference in patients who were undergoing acute versus chronic hemodialysis. There were three minor complications, and one patient died 6 days after the procedure because of multiple cardiovascular problems.

CONCLUSIONS

Renal artery stent placement for the treatment of RAS in patients receiving hemodialysis can result in discontinuation of hemodialysis in patients with low proteinuria level and adequate kidney size and eGFR.

[Hypertension in patients with renal artery stenosis]

Renal artery stenosis (RAS) is often present in patients with severe hypertension and atherosclerotic vascular disease. In this setting it is important to screen patients for renovascular disease, e.g. with Duplex-ultrasound, CT- or MR-angiography. The challenge of treating these patients is to find the evidence proving that the RAS is responsible for hypertension and/or renal dysfunction. Measurement of the intra-arterial pressure gradient is necessary in order to determine hemodynamic relevance. On the other side, in these patients hypertension is often of primary and/or renoparenchymatous origin and is aggravated by a renovascular disease. This explains why hypertension cannot be cured even if a high grade stenosis has been removed. In addition, thromb- and cholesterol-embolic material is often mobilized during an invasive procedure and leads to renaparenchymatous ischemia which sustains hypertension after intervention. An individual evaluation of profit versus risk is important for the decision for or against an invasive procedure, especially since there is no sufficient evidence for a decrease of mortality after interventions of RAS. The optimal conservative treatment, including the treatment of atherosclerotic risk factors is recommended.

Systemic inflammatory response to renal artery percutaneous angioplasty with stent placement and the risk for restenosis: a pilot study

PURPOSE

Time changes in plasma concentrations of six different cytokines were investigated to evaluate the inflammatory response to renal artery stent placement.

MATERIALS AND METHODS

A total of 22 patients (17 men; mean age, 66 years +/- 13) with ostial renal artery stenosis and poorly controlled hypertension treated with stent placement were studied. Blood samples were collected at baseline and at 24 hours and 6 months after the intervention. Plasma concentrations of (i) tumor necrosis factor-alpha, (ii) interleukin-6 (IL-6), (iii) monocyte chemoattractant protein-1, (iv) intercellular adhesion molecule-1, (v) vascular cell adhesion molecule-1, and (vi) regulated upon activatin normal T-cell expressed presumed secreted were measured. Restenosis diagnosed with imaging follow-up at 6 months was recorded. Plasma concentrations of the aforementioned cytokines were compared between patients with and without restenosis.

RESULTS

IL-6 concentration increased significantly 24 hours after stent placement (8.3 pg/mL +/- 1.24 vs. 2.76 pg/mL +/- 1.27 at baseline) and returned to baseline levels (2.6 pg/mL +/- 1.77) at 6-month follow-up (P < .0001). No significant changes occurred in the concentrations of any other cytokines at the three time points. Baseline and 6-month concentrations of IL-6 were significantly higher in patients with restenosis than in those without restenosis (8.13 pg/mL +/- 4 vs 0.75 pg/mL +/- 0.47 [P < .005] and 9.55 pg/mL +/- 6.5 vs 0.42 pg/mL +/- 0.35 [P < .02], respectively).

CONCLUSIONS

Renal artery angioplasty with stent placement induces an inflammatory response, as evidenced by increased IL-6 production. Additionally, IL-6 seems to identify patients prone to develop restenosis; therefore, it might be used as an early predictor of restenosis after renal angioplasty with stent placement. However, larger studies are required to confirm IL-6 as a potential predictor of restenosis.

[Atherosclerotic renal artery disease management update]

In the case of atherosclerotic renal artery disease, the best conclusive results lie principally not in the degree of the stenosis but rather in the degree the renal parenchymal disease beyond the stenosis itself. These determining factors involve the controlling of the patients blood pressure, the improvement in the renal function and the beneficial results to the cardiovascular system. Besides the indispensable medical treatment, a revascularisation by angioplasty may be indicated. This procedure with or without vascular stent often allows satisfactory angiographic results. A treatment by surgical revascularisation is only recommended in the case of extensive atherosclerotic lesions of the aorta, complex lesions of the latter or an abdominal aortic aneurism. Although the frequency of restenosis of angioplasty with stent remains extremely low, the risk of cholesterol emboli due to the diffuse atherosclerotic lesions of the abdominal aorta, must be considered at the time of each aortic catheterization. The therapeutic approach of atherosclerotic renal artery disease must be dictated by the whole cardiovascular risk factors and by the threat of target organs. The control of the blood pressure and the maintenance of the renal function must be integrated in the decisional algorithm as well as the possible risks in carrying out an eventual revascularisation procedure. Finally, the renal angioplasty should in numerous situations be integrated in the overall assumption of responsibility of the atherosclerotic vascular diseases, and should be part of the medical treatment. Several questions still do exist; at what moment an atherosclerotic renal artery stenosis should and e considered critical, and which procedure should be considered for which patient? The purpose of this review is to propose a decisional tool for individualized treatments in the light of results from randomized and controlled studies.

Embolic protection devices in patients with renal artery stenosis with chronic renal insufficiency: a clinical study

PURPOSE

To present clinical outcomes with the use of embolic protection devices (EPDs) and renal artery stents in patients with chronic renal insufficiency (CRI) and renal artery stenosis (RAS).

MATERIALS AND METHODS

A retrospective study was conducted in 23 patients with RAS and CRI who were treated with renal artery stent placement with an EPD. Follow-up data were obtained through medical records.

RESULTS

In 23 patients (18 men; 78%) with an average age of 69.4 years +/- 11 (range, 46-86 y), 32 renal arteries were treated for worsening renal function (n = 17; 74%) or uncontrolled hypertension and worsening renal function (n = 6; 26%). Nine FilterWire EZ devices were used in eight patients (35%) and 17 SpideRX devices were used in 15 patients (65%). The average follow-up was 8 months +/- 5. After the stent procedure, the mean systolic blood pressure decreased significantly (P < .05) whereas the diastolic pressure remained unchanged. There was a significant increase in the mean estimated glomerular filtration rate from 32.9 mL/min +/- 12.9 at baseline to 41.3 mL/min +/- 13.7 at last follow-up (P < .05). In 96% of patients, there was improvement or stabilization of kidney function. In six of the 17 SpideRX devices (35%), macroscopically evident embolic material was observed in the device after stent placement. There were two minor and two major complications.

CONCLUSIONS

Renal artery stent placement combined with the use of a SpideRX or FilterWire EZ device is associated with an good clinical outcome with a reasonable safety profile.

Restoration of failed renal graft function after successful angioplasty of pressure-resistant renal artery stenosis using a cutting balloon: a case report

This study is the report of a 37-year-old male with a transplanted kidney from a 3.5-year-old donor: the graft had two arteries transplanted with an aortic patch to an external iliac artery. Four months after transplantation, the graft function deteriorated, together with the development of hypertension. Stenosis of both graft arteries was detected and the patient was referred for angioplasty. The angiographic result was suboptimal, nevertheless, the graft function improved and was more or less stable (serum creatinine, 160-200 micromol/l) for 4 years, along with persistently difficult-to-control hypertension. Five years after transplantation, the graft function deteriorated again and severe graft artery restenosis was detected. The restenosis did not respond to dilatation, graft function failed, hypertension decompensated, and left ventricular failure developed. The patient required dialysis. A cutting balloon angioplasty opened the artery, and kidney function was restored after a few days: the serum creatinine level dropped to 140-160 micromol/l, and the glomerular filtration rate (creatinine clearance) to 0.65 ml/min/1.73 m(2). The graft function has now been stable for more than 2 years, however, the hypertension is still difficult to control.

Long-term follow-up of renal transplant patients with renal artery stenosis treated by percutaneous angioplasty

PURPOSE OF THE STUDY

To evaluate if renal angioplasty (PTRA) in patients with transplanted kidney and renal artery stenosis (TRAS) can have long-term effect on hypertension and renal function.

MATERIALS AND METHODS

Within a 24-year time period, 58 PTRAs in 55 adults (three times Re-PTRA) with transplanted kidney were performed. The group included 34 males and 21 females, average age 41+/-10.6 (18-72) years. After exclusion of 7 technical failures, 51 PTRAs were followed at 1 week, 6 months and 1-3 years after PTRA. Hypertension improvement was defined as mean arterial pressure (MAP) decrease of at least 15% from the pre-PTRA value. Graft function was evaluated by serum creatinine (Scr) and creatinine clearance (Ccr) levels, and the improvement was defined as a 20% change. Clinical FU was 3 years.

RESULTS

PTRA technical success was 88.4%. In 51 kidney recipients at the end of FU, blood pressure improved in 65.2% of patients (MAP decreased from 123+/-13.1 to 107+/-12.1 mmHg), but no patient remained normotensive medication free. Graft function improved in 44.8% of patients and was stabilized in 20.7% of them (average Ccr before PTRA: 0.48+/-0.29, after PTRA: 0.78+/-47 ml/s). PTRA complications were observed in 25.5% of procedures, most often with no clinical sequel. Thirty days mortality was 1.8% (one patient).

CONCLUSIONS

PTRA results in kidney recipients are valuable mainly in preserving graft function.

Computational representation and hemodynamic characterization of in vivo acquired severe stenotic renal artery geometries using turbulence modeling

The present study reports on computational fluid dynamics in the case of severe renal artery stenosis (RAS). An anatomically realistic model of a renal artery was reconstructed from CT scans, and used to conduct CFD simulations of blood flow across RAS. The recently developed shear stress transport (SST) turbulence model was pivotally applied in the simulation of blood flow in the region of interest. Blood flow was studied in vivo under the presence of RAS and subsequently in simulated cases before the development of RAS, and after endovascular stent implantation. The pressure gradients in the RAS case were many orders of magnitude larger than in the healthy case. The presence of RAS increased flow resistance, which led to considerably lower blood flow rates. A simulated stent in place of the RAS decreased the flow resistance at levels proportional to, and even lower than, the simulated healthy case without the RAS. The wall shear stresses, differential pressure profiles, and net forces exerted on the surface of the atherosclerotic plaque at peak pulse were shown to be of relevant high distinctiveness, so as to be considered potential indicators of hemodynamically significant RAS.

Revascularization for post-transplant renal artery stenosis

BACKGROUND

Percutaneous transluminal angioplasty has now been increasingly accepted as a primary treatment option for transplant renal artery stenosis.

METHODS

This single-centre study evaluated the treatment effect of percutaneous transluminal angioplasty as primary intervention among 18 consecutive patients with angiographically demonstrated transplant renal artery stenosis.

RESULTS

Patients (14 men and 4 women, mean age 49 +/- 9 years) were followed up for a mean duration of 21.6 months after procedure. Highly significant improvement was noted in the mean arterial pressure (from baseline 105.9 +/- 10.4 mmHg to 98.6 +/- 10.0 mmHg, P < 0.001), systolic blood pressure (148.5 mmHg to 137.1 mmHg, P = 0.002) and diastolic blood pressure (85.3 mmHg to 79.4 mmHg, P = 0.002). Estimated glomerular filtration rate before and 6 months after intervention was 41.4 +/- 16.8 mL/min per 1.73 m(2) and 42.0 +/- 16.2 mL/min per 1.73 m(2), respectively (P = 0.82).

CONCLUSION

These findings show that percutaneous transluminal angioplasty in transplant renal artery stenosis appears to have a significant beneficial effect on hypertension but less impact on the improvement in renal function.

Correlation of invasive Doppler flow wire with renal duplex ultrasonography in the evaluation of renal artery stenosis: The Renal Artery Stenosis Invasive Doppler (RAIDER) study

OBJECTIVE

Determining renal resistive index (RI) in the setting of renal artery stenosis may predict which patients benefit from revascularization. Renal duplex ultrasonography (RDUS) is the traditional method of assessing RI, but it is not available in most invasive endovascular laboratories. Conversely, endovascular techniques to assess RI are available but not well validated. The primary goal was to determine if an invasive approach using an endovascular Doppler flow wire correlates with RI assessment using traditional noninvasive RDUS.

METHODS

In a single-center prospective trial, patients were enrolled if they had known or suspected renovascular disease. A Doppler flow wire was placed in multiple segments of the renal artery, and peak (PSV) and end-diastolic velocities (EDV) were measured. RI was calculated using the formula: RI = [1 - (EDV/PSV)] x 100. Similarly, RI was also derived using standard RDUS. All patients underwent both RI techniques before any revascularization procedure. Secondary end points included assessing the correlation for pole-to-pole renal length assessment and PSV and EDV velocities using both invasive and noninvasive techniques. Pearson correlation coefficient calculations were used to determine degree of correlation.

RESULTS

The study enrolled 20 patients, and 35 renal arteries were studied. Overall, Pearson correlation coefficient for invasive vs noninvasive RI assessment was 0.86 (95% confidence interval [CI], 0.73 to 0.93). The r values were 0.43 (95% CI, 0.11 to 0.67) for pole-to-pole renal length, 0.66 (95% CI, 0.54 to 0.76) for PSV, and 0.61 (95% CI, 0.48 to 0.72) for EDV determination. No major complications occurred during this study. Average time to perform invasive Doppler assessment was 10.4 +/- 7.4 minutes per artery.

CONCLUSIONS

Invasive RI assessment using an endovascular flow wire technique correlates well with traditional noninvasive RDUS. A moderate statistical correlation also exists for pole-to-pole renal length, PSV, and EDV determinations. The procedure is safe and can be performed rapidly.