Long-term renal function preservation after renal artery stenting in patients with progressive ischemic nephropathy

Outcomes after stenting of renal artery stenosis in patients with high-risk clinical features

BACKGROUND

In patients with renal artery stenosis, revascularization was seen as a mean to improve outcomes, but large studies failed to show significant benefit in general population. However, data on benefits of renal artery stenting in patients with high-risk features, such as rapidly declining renal function and cardiac destabilization syndromes, are limited, as they were excluded from trials. In this descriptive study, we aimed to evaluate short- and long-term outcomes in high-risk patients with renal artery stenosis, treated by angioplasty and stenting. We have retrospectively interrogated our local databases for renal artery percutaneous interventions; patients at high-risk (rapidly declining renal function; stable chronic renal failure and bilateral renal artery disease; severe hypertensive crisis) were selected for the current analysis.

RESULTS

Of 30 patients undergoing renal artery stenting, 18 patients were deemed "high-risk." On short term, good in-hospital control of hypertension and cardiac stabilization were obtained in all patients. Renal function improved significantly only in patients admitted with rapidly declining renal function, with significant creatinine level fall from median 3.98 mg/dL to 2.02 mg/dL, p = 0.023. However, for the whole group, creatinine change was non-significant (- 0.12 mg/dL, p = NS). On the long term, five patients (27.8%) ended-up on chronic hemodialysis and six patients died (33.3%) after a median of 20 months. No death occurred during the first year after the procedure.

CONCLUSIONS

Percutaneous procedures are feasible and safe in patients with high-risk renal artery stenosis, especially in those with rapidly declining renal function, probably saving some of them from the immediate need for renal replacement therapy, but long-term results are negatively influenced by the precarious general and cardio-vascular status of these patients and by the pre-existing significant renal parenchymal disease, non-related to the renal artery stenosis.

Ultra-Low-Dose Contrast Using Transluminal Renal Angioplasty: The ULTRA Study

BACKGROUND

Although severe atherosclerotic renal artery stenosis (ARAS) is a predictor of future cardiovascular events, large trials have not shown the benefits of percutaneous transluminal renal angioplasty (PTRA). This study aimed to validate the safety and efficacy of PTRA using low-concentration digital subtraction angiography (LC-DSA) in patients with severe ARAS and advanced chronic kidney disease (CKD).

MATERIALS AND METHODS

This prospective study was conducted between August 2018 and October 2021. Eighteen patients with 20 lesions, CKD stage 3b or worse, and significant renal artery stenosis were included and underwent PTRA using ultra-low-dose contrast medium. The primary endpoint was a change in renal function based on serum creatinine (sCr) level.

RESULTS

The mean sCr level significantly improved from 3.34 ± 1.8 mg/dL pre-PTRA to 2.48 ± 1.19 mg/dL at 1 month post-PTRA (P = .02). The mean amount of contrast used was 8.3 ± 3.9 mL per vessel. More severe stenosis and rapid deterioration of renal function before treatment were associated with improved kidney function. No cardiovascular or renal complications such as stroke or contrast-induced nephropathy were observed during the 30-day period.

CONCLUSIONS

PTRA using an ultra-low-dose contrast medium is safe and provides acceptable results.

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.

Percutaneous Endovascular Therapy of Renal Artery Stenosis: Technical and Clinical Developments in the past Decade

Renal artery stenosis may initiate or exacerbate arterial hypertension and/or renal insufficiency. During the last decade, technical improvements of diagnostic and interventional endovascular tools have led to more widespread use of endoluminal renal artery revascularization and broader indications for this type of therapy. Since the first renal artery angioplasties performed by Felix Mahler and Andreas Grüntzig in 1978, numerous single-center studies have documented the benefits of percutaneous renal revascularization. In the early 1990s, stent implantation was added to the interventionist's armamentarium for treating renal artery stenosis due to atherosclerosis or fibromuscular dysplasia. The metaanalysis of 3 randomized studies comparing balloon angioplasty with best medical therapy found intervention to be beneficial for blood pressure control but not for preservation of renal function. Despite the absence of randomized studies, there is mounting evidence that stenting of hemodynamically relevant atherosclerotic renal artery stenosis has a positive impact on blood pressure control and renal function. This article summarizes the technical improvements in these endovascular tools during the last decade and gives an overview concerning their clinical impact on renal artery revascularization.

Renal Artery Stenosis: Optimal Therapy and Indications for Revascularization

Atherosclerotic renal artery stenosis (ARAS) is associated with increased cardiovascular risk and overall mortality. Manifestations of ARAS include resistant or malignant hypertension, progressive deterioration of renal function, and cardiac dysfunction syndromes of flash pulmonary edema and angina. Diagnosis rests upon non-invasive studies such as duplex ultrasonography and is confirmed using invasive renal arteriography. Regardless of the severity of ARAS, management of this entity has been a topic of contentious debate. For over two decades, the use of percutaneous revascularization to treat ARAS has been studied with various clinical trials. Though case series seem to demonstrate favorable clinical response to revascularization, the overwhelming majority of randomized clinical trials have not mirrored a robust outcome. In these trials, poor correlation is noted between the reduction of stenosis and the improvement of renovascular hypertension and glomerular filtration rate, and decrease in cardiovascular outcomes and mortality. With dichotomizing results, the explanation for these discrepant findings has been attributed to improper trial design and inappropriate patient selection. An overview of the treatment options available will be provided, with a focus on the methodology and design of clinical trials investigating the efficacy of percutaneous revascularization. Emphasis is placed on appropriate patient selection criteria, which may necessitate the use of hemodynamic lesion assessment and clinical correlation based on individualized care. When clinical equipoise exists between optimal medical therapy and revascularization, the current paradigm supports ongoing medical therapy as the treatment of choice. However, renal artery stenting remains a viable therapeutic option for those who continue to have clinical syndromes consistent with renal hypoperfusion while adequately treated with optimal medical therapy. Despite observational studies suggesting clinical benefit for this specific patient population, there remains a paucity of randomized clinical trial data. Further trials targeting the patients who are inadequately treated with optimal medical therapy need to be undertaken to confirm the efficacy of revascularization.

Mortality and Renal Replacement Therapy after Renal Artery Stent Placement for Atherosclerotic Renovascular Disease

PURPOSE

To identify risk factors for progression to renal replacement therapy (RRT) and all-cause mortality in patients who underwent renal artery (RA) stent placement for atherosclerotic renal artery stenosis (RAS).

MATERIALS AND METHODS

A retrospective study from June 1996 to June 2009 identified 1,052 patients who underwent RA stent placement. Glomerular filtration rate at time of RA stent placement was estimated from serum creatinine level and divided into chronic kidney disease (CKD) stages 1-5. Univariate and multivariable Cox proportional hazards models were used to determine which factors were associated with each endpoint.

RESULTS

Times to progression to all-cause mortality and RRT were similar for CKD stages 1/2/3A and served as the reference group. In multivariable analysis, high-grade proteinuria (P < .001) and higher CKD stage (5 vs 1/2/3A [P < .001], 4 vs 1/2/3A [P < .001], 3B vs 1/2/3A [P = .02]) remained independently associated with increased risk of progression to RRT. Angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) use was associated with decreased risk of progression to RRT (P = .03). Higher CKD stage (5 vs 1/2/3A [P < .001], 4 vs 1/2/3A [P = .004]), carotid artery disease (P < .001), diabetes mellitus (P = .002), and high-grade proteinuria (P < .001) remained independently associated with all-cause mortality. Statin use was associated with decreased risk of all-cause mortality (P < .001).

CONCLUSIONS

Patients with atherosclerotic RAS who undergo RA stent placement and have high-grade proteinuria and CKD stage 3B/4/5 have increased risk of progression to RRT. Patients with high-grade proteinuria, CKD stage 3B/4/5, carotid artery disease, or diabetes have increased risk for all-cause mortality after renal artery stent placement. Patients receiving ACEI/ARBs have a decreased risk of progression to RRT, and patients receiving statins have a decreased risk of all-cause mortality.

Update on intervention versus medical therapy for atherosclerotic renal artery stenosis

Atherosclerotic renal artery stenosis is known to be one of the most common causes of secondary hypertension, and early nonrandomized studies suggested that renal artery stenting (RASt) improved outcomes. The vascular community embraced this less invasive treatment alternative to surgery, and RASt increased in popularity during the late 1990s. However, recent randomized studies have failed to show a benefit regarding blood pressure or renal function when RASt was compared with best medical therapy, creating significant concerns about procedural efficacy. In the wake of these randomized trial results, hypertension and renal disease experts along with vascular interventional specialists now struggle with how to best manage atherosclerotic renal artery stenosis. This review objectively analyzes the current literature and highlights each trial's design weaknesses and strengths. We have provided our recommendations for contemporary treatment guidelines based on our interpretation of the available empirical data.

Renal Stenting for Kidney Salvage in the Management of Renal Artery Atherosclerotic Stenosis

We studied the usefulness of preoperative resistance index to select patients who will benefit most from renal stenting. Sixty-two patients underwent renal stenting. All had chronic renal insufficiency with serum creatinine values ranging from 1.5 to 2.5 mg/dL and blood urea nitrogen between 80 and 107 mg/dL. All treated renal artery stenosis were >70%. Reduction in blood pressure in the early stages was observed in 39 (62.9%) patients; 31 (79.4%) patients returned to preoperative values within 12 months. A progressive reduction in creatinine values and blood urea nitrogen was reached in 43 (69.4%) patients, 12 (19.4%) patients remained unchanged, and the remaining 7 (11.2%) patients worsened. The best improvement in renal function was obtained in patients with a resistance index of ≤0.75 A preoperative resistance index up to 0.75 could be used as an indicator to predict which candidates will have improved renal function after stenting.

Technical discussion of diagnostic angiography and intervention of atherosclerotic renal artery stenosis

Renal artery stenting remains an important adjuvant treatment for true-resistant hypertension, although recent disappointing randomized trials highlight the importance of careful patient selection. Safe and successful renal interventions begin with critical core knowledge regarding renal artery anatomy and understanding the often hostile nature of the parent vessel (pararenal aorta). Armed with fundamental knowledge about anatomy and renal ostial disease pathology, it becomes easier to understand the advantages of less traumatic access techniques and how low-profile contemporary flexible stents have enhanced outcomes. In addition to suggested techniques based on detailed understanding of the vessel architecture and pathology, we will review the current available US Food and Drug Administration-approved balloon-expandable on-label renal stents and discuss the role of intravascular ultrasound for definition of lesion severity, stent sizing, and stent apposition. The durability of renal stenting will also be discussed, as will the velocity criteria for duplex surveillance. Lastly, the current empirical data related to renal embolic protection is provided, along with insight into technical issues in this domain.

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.

Renal artery stenosis: prevalence of, risk factors for, and management of in-stent stenosis

Atherosclerotic renal artery stenosis is common and is associated with hypertension and chronic kidney disease. More frequent use of percutaneous renal artery stent placement for the treatment of renal artery stenosis during the past 2 decades has increased the number of patients with implanted stents. In-stent stenosis is a serious problem, occurring more frequently than earlier reports suggest and potentially resulting in late complications. Currently, there are no guidelines covering the approach to restenosis after renal artery stent placement. This article reviews data on the prevalence of and risk factors for the development of in-stent stenosis and the clinical manifestations, evaluation, and treatment of in-stent stenosis and suggests a strategy for the management of patients after percutaneous renal artery stent placement.

Atherosclerotic renal artery stenosis--diagnosis and treatment

Renal artery stenosis (RAS) is characterized by a heterogeneous group of pathophysiologic entities, of which fibromuscular dysplasia and atherosclerotic RAS (ARAS) are the most common. Whether and which patients should undergo revascularization for ARAS is controversial. The general consensus is that all patients with ARAS should receive intensive medical treatment. The latest randomized clinical trials have increased confusion regarding recommendations for revascularization for ARAS. Although revascularization is not indicated in all patients with ARAS, experts agree that it should be considered in some patients, especially those with unstable angina, unexplained pulmonary edema, and hemodynamically significant ARAS with either worsening renal function or with difficult to control hypertension. A search of the literature was performed using PubMed and entering the search terms renal artery stenosis, atherosclerotic renal artery stenosis, and renal artery stenosis AND hypertension to retrieve the most recent publications on diagnosis and treatment of ARAS. In this review, we analyze the pathways related to hypertension in ARAS, the optimal invasive and noninvasive modalities for evaluating the renal arteries, and the available therapies for ARAS and assess future tools and algorithms that may prove useful in evaluating patients for renal revascularization therapy.

Endovascular intervention for renal artery stenosis

Renovascular diseases are common conditions with important implications on cardiovascular morbidity and mortality. Renal artery stenosis (RAS) is present in 1-5% of patients with hypertension (HTN) in the US with the vast majority of caused by atherosclerosis. Atherosclerotic RAS is related not only to uncontrolled HTN, but also to renal dysfunction. Atherosclerotic RAS in the USA has been reported to account for approximately 14-16% of new patients requiring dialysis each year. Hence a concerted effort was made in the last decade to treat renovascular stenosis using newly developed endovascular therapies to improve cardiovascular morbidity and renal function. A review on new advances in the endovascular management of renal artery stenosis with low profile stents, embolic protection devices, and drug eluting stents is presented.

Clinical efficacy of percutaneous renal revascularization with stent placement in hypertension among patients with atherosclerotic renovascular diseases

AIM

The aim was to assess the effect of renal angioplasty with stent on systolic, diastolic, and mean arterial blood pressure (MAP) in awake and sleep time with ambulatory blood pressure (ABP) monitoring (Holter monitoring).

MATERIALS AND METHODS

Patients with angiographically proven atherosclerotic renal artery stenosis (RAS) were referred to the Angiography Department of Imam Hospital for intervention during a 1-year period from June 2008 to December 2009. Primary stent placement was attempted by a single operator in 27 severe RAS cases although 1 case was omitted from the study because of technical failure. Pre- and postprocedure creatinine levels, ejection fraction (EF), history of diabetes mellitus (DM), and ABP were obtained. Twenty-six (17 men, 9 women; average age, 62.6 years; age range, 90-21 years) consecutive patients participated in the study.

RESULTS

All patients had severe hypertension resistant to multiple medications; 10 patients had impaired renal function (serum creatinine level greater than 130 µmol/L). A total of 3 (11.5%) patients had congestive heart failure, and 10 (37.7%) were diabetic. Hypertension was cured in 1 (4%) patient, had improved in 23 (88.4%) patients, and had failed to respond to treatment in 2 (7.6%). Serum creatinine decreased significantly from 1.46 ± 0.89 to 1.35 ± 0.61 mg/dL (P<0.05).

CONCLUSION

Percutaneous transluminal angioplasty for atheromatous RAS rarely cures hypertension, but improved blood pressure control is often achieved.

Effect of baseline glomerular filtration rate on renal function following stenting for atherosclerotic renal artery stenosis

OBJECTIVE

Percutaneous transluminal renal artery angioplasty and stenting (PTRAS) is one treatment option for atherosclerotic renal artery stenosis (ARAS). However, factors predicting the outcome remain controversial. This study investigated the effect of the baseline glomerular filtration rate (GFR) on renal function after PTRAS in patients with ARAS.

MATERIAL AND METHODS

Patients who underwent PTRAS due to significant ARAS (luminal narrowing > or = 60%) were enrolled. The patients were divided into control (n = 57; estimated GFR (eGFR) > or = 60 ml/min/1.73 m(2)) and chronic renal failure (CRF) groups (n = 53; eGFR < 60 ml/min/1.73 m(2)), according to the baseline eGFR.

RESULTS

The mean age at the time of PTRAS was 62 +/- 9 years, and the mean duration of follow-up was 50 +/- 26 months. There was a significant decrease in eGFR after PTRAS in the control group, whereas the CRF group showed no significant change in eGFR. The percentage change in eGFR was negatively correlated with the baseline eGFR (r = -0.274, p = 0.004). Multivariate linear regression revealed that only baseline eGFR predicted the change in eGFR (p = 0.032).

CONCLUSIONS

PTRAS was more effective at preserving renal function in patients with moderately impaired renal function. Thus, baseline GFR may indicate the expected renal function outcome after PTRAS.

Renal parenchymal preservation after percutaneous renal angioplasty and stenting

BACKGROUND

The intent of endovascular therapy for symptomatic atherosclerotic renal artery stenosis (ARAS) is to preserve parenchyma and avoid renal-related morbidity. The aim of this study is to examine the impact of renal artery intervention on parenchymal preservation.

METHODS

We performed a retrospective analysis of records from patients who underwent endovascular intervention for ARAS and were followed by duplex ultrasound between 1990 and 2008. Renal volume (in cm(3)) was estimated in all patients as renal length (cm) x renal width (cm) x renal depth (cm) x 0.5. The normal renal volume was calculated as 2 x body weight (kg) in cm(3). Failure of preservation was considered to be a persistent 10% decrease in volume. Clinical benefit defined as freedom from renal-related morbidity (increase in persistent creatinine >20% of baseline, progression to hemodialysis, death from renal-related causes) was calculated.

RESULTS

Five hundred ninety-two renal artery interventions were performed. One hundred eighty-six kidneys suffered parenchymal loss (>5%) with an actuarial parenchymal loss rate of 29% +/- 1% at five years respectively. There were no significant differences in age, gender, starting renal volume, or kidney size. However, patients with parenchymal loss had lower eGFR (45 +/- 24 vs 53 +/- 24 mL/min/1.73 m(2); Loss vs noLoss, P = .0002, Mean +/- SD) higher resistive index (0.75 +/- 0.9 vs 0.73 +/- 0.10; P = .0001) and worse nephrosclerosis grade (1.43 +/- 0.55 vs 1.30 +/- 0.49; P = .006) then those not suffering parenchymal loss. Parenchymal loss was associated with significantly worse five-year survival (26% +/- 4% vs 48% +/- 2%; Loss vs noLoss; P < .001) and freedom from renal-related morbidity (70% +/- 5% vs 82% +/- 2%; P < .05) with increased numbers progressing to dialysis (17% vs 7%; P < .006).

CONCLUSION

While parenchymal preservation occurs in most patients, parenchymal loss occurs in 31% of patients and is associated with markers of impaired parenchymal perfusion (resistive index and nephrosclerosis grade) at the time of intervention. Pre-existing renal size or volumes were not predictive of parenchymal loss. Parenchymal loss is associated with a significant decrease in survival and a marked increased renal related morbidity and progression to hemodialysis.

Management of renal artery stenosis: the case for intervention, defending current guidelines, and screening (drive-by) renal angiography at the time of catheterization

There is little debate that an untreated significant obstruction of blood flow to the kidney, most often due to atherosclerosis, is potentially hazardous to the health of patients. The treatment of atherosclerotic renovascular disease has evolved over the past 20 years from open surgery with its inherent morbidity and risk of mortality to percutaneous endovascular treatment with stents. The current debate is on the question of which patients are offered any additional advantage by revascularization for renal artery stenosis over medications alone. The primary issue is patient selection, including the most appropriate screening strategies for renal artery stenosis, which must be balanced against the risk of procedure-related complications. The goal of this paper is to explore the most appropriate utilization of revascularization with renal stent placement.

[Management of renal atrophy in hypertensive patients: experience in Lille]

INTRODUCTION

In the absence of specific treatment, patients with renal vascular disease develop renal atrophy. This population frequently has hypertension refractory to medical treatment. The patients who may respond to revascularization or at the worst to a nephrectomy must be identified to optimize their therapeutic management.

METHODS

We conducted an observational retrospective study of hypertensive patients with unilateral renal atrophy (renal height < 9 cm) followed at the Lille University Hospital Center from 1998 to 2006. Hypertension, renal clearance (by scintigraphy with MAG3), and hypersecretion of renin (segmental/selective venous renin samples) were studied. We subsequently classified the patients into 3 groups. Medical treatment was optimized for all.

RESULTS

The mean follow-up period was 1.3+/-0.2 years. Eight patients were treated medically (group 1). Endovascular revascularization was used to treat the subjects for which atrophic kidney function accounted for more than 10% of their total renal function and with stenosis of the renal artery (>70%) (group 2, n=19). Those with a small nonfunctional kidney (<10% of total renal function) and hypersecretion of renin (ratio>1.5 in relation to the contralateral kidney) underwent a nephrectomy (group 3, n=8). The reduction in systolic blood pressure (SBP) was 27 mm Hg and diastolic blood pressure (DBP) 14 mm Hg for the overall study population (p < 0.001), without any significant aggravation of renal function. In group 1, the reduction in blood pressure was lower, with medical treatment alone; SBP fell by 13 mm Hg and DBP by 4mm Hg (p=ns) ; this group had the lowest initial blood pressure. In group 2, revascularization made it possible to improve SBP by 26 mm Hg and DBP by 14 mm Hg (p < 0.01) without significant impairment of renal function. Group 3 showed the most spectacular improvement in blood pressure, with SBP dropping by 40 mm Hg and DBP by 19 mm Hg (p=0.016). But it was also in this group that we observed an aggravation in the rate of glomerular filtration with a nonsignificant reduction of 12.8 mL/min, nonetheless superior to that expected according to the preoperative scintigraphy.

CONCLUSION

The results of this work underline the importance of multidisciplinary management of patients with small ischemic kidneys. Preselection of patients in unstable clinical situations (refractory hypertension, progressive kidney failure, flash pulmonary edema) by isotopic and endocrinal renal evaluation provides a basis for deciding on treatment. The existence of a renin ratio >1.5 can identify the patients most likely to respond to nephrectomy. The reduction of renal function following nephrectomy must be considered in the discussion about treatment. The functional threshold initially defined at 10% may be lowered to 5%, to limit this postoperative reduction.

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.

Transient and persistent renal dysfunction are predictors of survival after percutaneous coronary intervention: insights from the Dartmouth Dynamic Registry

OBJECTIVES

We sought to determine if transient and persistent elevations in creatinine following percutaneous coronary intervention (PCI) resulted in poor survival.

BACKGROUND

Limited survival data exist that defines the natural survival history of transient and persistent renal dysfunction following interventional PCI cases.

METHODS

Data were collected prospectively on 7,856 consecutive patients undergoing PCI from January 1, 2000 to July 31, 2006. Ninety-three patients were excluded due to pre-PCI dialysis. Patients were stratified into three categories of renal dysfunction: no renal dysfunction from baseline (<0.5 mg/dL increase in creatinine within 48 hr of the procedure), transient renal dysfunction (> or =0.5 mg/dL increase in creatinine within 48 hr with return to normal within 2 weeks), and persistent renal dysfunction (> or =0.5 mg/dL increase in creatinine without returning to normal within 2 weeks of the procedure). Mortality was determined by comparing with the Social Security Death Master File.

RESULTS

Median survival was 3.2 years (mean 3.4). Renal dysfunction occurred in 250 patients (0.5 mg/dL increase in creatinine). Survival was significantly different between patients at 1, 3.2, and 7.5 years (P-value < 0.001): no renal dysfunction (95%, 88%, 75%), with transient (61%, 42%, 0%), and with persistent (58%, 44%, 36%) renal dysfunction. Patients with transient or persistent renal dysfunction had a twofold-threefold increased risk of 7.5-year mortality compared with patients with no renal dysfunction.

CONCLUSIONS

Both transient and persistent postprocedural renal dysfunction are prognostically significant for mortality during extended follow-up. Renal dysfunction should be closely monitored before and after PCI.

Serum Creatinine Stabilization Following Renal Artery Stenting

The impact of renal artery stenting on renal function in a subgroup of consecutive de novo patients with atherosclerotic renal artery stenosis from the single operator, single center, retrospective renal stent trial is defined. Patients with inadequate preprocedure and/or follow-up renal function studies were excluded. Abnormal baseline serum creatinine (sCr) was defined as ≥1.5 mg/dL. Follow-up sCr was improved, unchanged, or worsened if the variance from baseline decreased by >20%, stayed within 20%, or increased >20%, respectively. For the total cohort (194 patients), renal function stabilized or improved in 72% of patients. Plotting 1/sCr demonstrated a decline in renal function before the procedure that stabilized following renal artery stenting. Bilateral renal artery stenting predicted normal follow-up sCr, and baseline sCr >2.1 mg/dL was associated with improvement in sCr long-term. In conclusion, renal artery stenting results in overall stabilization of renal function, and bilateral renal artery stenting seems to have added benefit.

Treatment of renovascular hypertension by transluminal angioplasty--13 years experience in a single centre

OBJECTIVE

The study is a follow-up on treatment of renovascular hypertension (RVH) with percutaneous transluminal renal angioplasty (PTRA).

METHODS

Patients were screened on the basis of clinical criteria of increased probability of RVH with renography and in selected cases with renal vein renin measurements. A positive work-up suggesting a functionally important renal artery stenosis led to renal angiography and PTRA if stenosis was confirmed; in 59%, an intravascular stent was inserted.

RESULTS

Outcome of treatment was classified as follows - group I: normotensive without medication; group II: with improved control of blood pressure; group III: unchanged blood pressure control. Grouping was performed immediately after treatment, at 1 month, 6 months and at the latest follow-up. One hundred-and-twenty-two patients (124 atherosclerotic and 12 fibromuscular lesions) were treated during 13 years. Immediately after PTRA the patients were grouped as follows - I: 31%, II: 59%, III: 10%. At 1 month, I: 13%, II: 72%, III: 15%; at 6 months, I: 11%, II: 74%, III: 15%, and at the latest follow-up, I: 11%, II: 78%, III: 11%. There were few significant complications, and renal function remained on average stable.

CONCLUSION

PTRA is an effective treatment of RVH in patients selected by signs of a flow-restricting stenosis. Twelve percent were normotensive after angioplasty and a further 77% had better controlled hypertension. Few complications were seen and renal function was on average unchanged as measured by serum creatinine.

Catheter-based therapy for atherosclerotic renal artery stenosis

The prevalence of atherosclerotic renal artery stenosis (RAS) is more common than was previously thought, particularly in patients with known coronary, cerebrovascular, or peripheral vascular atherosclerosis. Clinical subsets in which RAS is more common include patients with uncontrolled hypertension, renal insufficiency, and/or sudden onset ("flash") pulmonary edema. Renal artery atherosclerosis progresses over time and is associated with loss of renal function regardless of medical therapy. Patients with symptomatic (hypertension, renal insufficiency, or flash pulmonary edema) and hemodynamically significant RAS are potential candidates for revascularization. The current standard of care is stent placement for aorto-ostial atherosclerotic lesions. Procedure success rates are very high (> or =95%), with infrequent major complication rates. Five-year primary patency rates are 80% to 85%, and secondary patency rates exceed 90%. The key element in managing patients with RAS is selecting those most likely to benefit, that is, those with blood pressure control, preservation or improvement of renal function, and control of flash pulmonary edema from renal revascularization. This article will highlight the anatomical features, physiologic parameters, and biomarkers that may be helpful in optimally selecting patients for renal artery revascularization.

Current Treatment of Peripheral Arterial Disease

Despite advances in medical therapies to help prevent the development of atherosclerosis and improve the management of patients with established peripheral arterial disease (PAD), the prevalence of PAD and associated morbidity remains high. Over the past decade, percutaneous revascularization therapies for the treatment of patients with PAD have evolved tremendously, and a great number of patients can now be offered treatment options that are less invasive than traditional surgical options. With the surgical approach, there is significant symptomatic improvement, but the associated morbidity and mortality preclude its routine use. Although newer percutaneous treatment options are associated with lower procedural complications, the technical advances have outpaced the evaluation of these treatments in adequately designed clinical studies, and therapeutic options are available that may not have been rigorously investigated. Therefore, for physicians treating patients with PAD, an understanding of the various therapies available, along with the inherent benefits and limitations of each treatment option is imperative as a greater number of patients with PAD are being encountered.

Management of atherosclerotic renovascular disease: the effect of renal artery stenting on renal function and blood pressure

In the last few years, renal artery stenting has gradually evolved into one of the most important therapeutic modalities in the management of atherosclerotic renovascular disease. Stenting is nowadays preferred by a steadily increasing number of physicians, not only because of its significant contribution to blood pressure control, but also because of its documented ability to maintain, and even improve, renal function. At the same time, procedure-related morbidity and mortality rates are extremely low, while recurrent stenosis rates have been repeatedly reported to be minimal. Percutaneous transluminal renal angioplasty (PTRA) and stenting are nowadays considered by many physicians to be the treatment of choice for atherosclerotic renovascular disease.

Factors affecting long-term survival following renal artery stenting

INTRODUCTION

This study defines clinical variables at the time of renal artery stenting that may be predictors of long-term all-cause mortality.

METHODS

The data are derived from the single operator, single center, renal stent retrospective study (SOCRATES) and includes a review of 748 (336 men, 412 women) consecutive symptomatic patients with de novo atherosclerotic renal artery stenosis treated over an 11-year period. All patients had clinical indications for renal revascularization, including, but not limited to; suboptimal control of hypertension, chronic kidney disease, and cardiac disturbance syndromes. Clinical variables at the time of the index procedure were evaluated as predictors of all-cause mortality using multivariate analysis. Mortality data were derived from hospital records and formal queries of the State Department of Health and Human Services, Health and Vital Statistics Division database.

RESULTS

In-hospital, 30-day and 6-month mortality rates were 0.5, 2.0, and 6.3%, respectively. Overall patient survival at years 1, 5, and 10 was 91.2, 66.6, and 40.9%, respectively. Comorbid conditions, including chronic obstructive pulmonary disease and congestive heart failure, were independently associated with increased mortality. There were incremental changes in mortality in patients with baseline azotemia, [preprocedure serum creatinine (sCr) 1.5-2.09 mg/dL hazard ratio 1.52; sCr >2.5 mg/dL hazard ratio 3.39]. Therapy with lipid lowering agents offered a survival advantage (hazard ratio 0.69, P = 0.0.049); however, this study was not designed to evaluate a "protective effect" of lipid lowering medications.

CONCLUSIONS

Patients with chronic obstructive pulmonary disease and congestive heart failure undergoing renal artery stent revascularization have a poor long-term prognosis. Baseline azotemia is the strongest independent predictor of all cause mortality, with more than 70% of patients with marked azotemia (sCr >2.5) dead at 5 years.

Treatment of instent restenosis following stent-supported renal artery angioplasty

OBJECTIVES

We prospectively studied the long-term outcome of endovascular treatment of instent renal artery stenosis (IRAS).

BACKGROUND

Restenosis is a considerable drawback of stent-supported angioplasty of renal artery stenosis especially in small vessel diameters. The appropriate treatment strategy is not yet defined.

PATIENTS AND METHODS

During a 10-year period 56 consecutive patients (65 lesions) with their first IRAS were included in a prospective follow-up program (mean follow-up 53 +/- 25 months, range 6-102). Primary endpoint of the study was the reoccurence of IRAS (>or= 70%) after primarily successful treatment of the first IRAS determined by duplex ultrasound.

RESULTS

Primary success rate was 100%, no major complication occurred. Nineteen lesions were treated with plain balloon angioplasty (group 1, 30%), 42 lesions with stent-in-stent placement (group 2, 65%) using various bare metal balloon expandable stents, and 4 lesions with drug-eluting stent angioplasty (group 3, 6%). During follow-up, overall 21 lesions (32%) developed reoccurence of IRAS: n = 7/19 in group 1 (37%), n = 14/42 in group 2 (33%), and n = 0/4 in group 3 (0%; P = 0.573). Reoccurence of IRAS was more likely to occur in smaller vessel diameters than in larger ones [3-4mm: 4/7 (57%); 5 mm: 11/26 (42%); 6 mm: 5/25 (20%); 7 mm: 1/7 (14%), P = 0.088]. Multivariable analysis found bilateral IRAS and IRAS of both renal arteries of the same side in case of multiple ipsilateral renal arteries as independent predictors for reoccurence of IRAS.

CONCLUSION

Treatment of IRAS is feasible and safe. The data demonstrate a nonsignificant trend towards lower restenosis with restenting of IRAS versus balloon angioplasty of IRAS. Individual factors influence the likelihood of reoccurence of IRAS.

Diabetes mellitus does not preclude stabilization or improvement of renal function after stent revascularization in patients with kidney insufficiency and renal artery stenosis

OBJECTIVE

To assess the impact of stent revascularization on the renal function of diabetic and nondiabetic patients with renal insufficiency.

BACKGROUND

Renal artery revascularization has been shown to stabilize or improve renal function in patients with significant renal artery stenosis and impaired renal function. However, some studies have suggested negligible or no benefit of renal function in diabetic patients with the same condition.

METHODS

We retrospectively compared data from 50 consecutive patients undergoing renal artery stent placement with renal insufficiency (serum creatinine > or = 1.5-4.0 mg/dl) and global ischemia (bilateral or solitary [single] kidney renal artery stenosis) There were 17 diabetic (DM) and 33 nondiabetic (NDM) patients. The endpoints included the follow-up measurements of renal function, blood pressure, and number of antihypertensive medications.

RESULTS

After stent placement, at a mean follow-up of 42 +/- 18 months (range: 6-62 months), 79% NDM (N = 26), and 76% DM patients (N = 13) (P = NS) had improvement in the slope of the reciprocal of creatinine (1/SCr), indicating a beneficial effect in renal function in many patients.

CONCLUSION

Renal artery stent placement appears to be equally beneficial in preserving renal function in DM and NDM patients with ischemic nephropathy and global renal ischemia.

Treatment of reoccurring instent restenosis following reintervention after stent-supported renal artery angioplasty

BACKGROUND

Reoccurrence of restenosis following angioplasty of renal instent restenosis is a considerable drawback of stent-supported angioplasty of renal artery stenosis especially in small vessel diameters. We therefore prospectively studied the long-term outcome of different techniques of endovascular treatment of reoccurrence of instent renal artery restenosis after primarily successful reangioplasty focusing on the impact of covered and drug eluting stents, respectively.

PATIENTS AND METHODS

The study included 31 consecutive patients (33 lesions) presenting with their at least second instent restenosis following renal artery stenting who were included in a prospective follow-up program (mean follow-up 36+/-25 months, range 1-85). Primary endpoint of the study was the reoccurrence rate of instent stenosis after primarily successful treatment of instent restenosis determined by duplex ultrasound.

RESULTS

Primary success rate was 100%, no major complication occurred. Seven lesions were treated with balloon angioplasty (21%, group 1), 7 lesions with stent-in-stent placement (21%, group 2), 6 lesions with placement of a covered stent (18%, group 3), 3 lesions with a cutting balloon (9%, group 4), and 10 lesions with placement of a drug eluting stent (31%, group 5). During follow-up, overall 12 lesions (36%) developed reoccurrence of instent restenosis: n=5 in group 1 (reoccurrence rate 71%), n=3 in group 2 (43%), n=1 in group3 (17%), 3 in group 4 (100%), and n=0 in group 5 (0%). Treatment with a cutting balloon was the only significant predictor of restenosis (hazard ratio 32.3 (95% CI, 3.3-315.0); P<0.001).

CONCLUSION

Treatment of at least second renal artery instent restenosis is feasible and safe. Balloon angioplasty and the implantation of a bare metal stent, a covered stent, or a drug eluting stent seemed to offer favorable long-term patency, whereas cutting balloon angioplasty resulted in a very high rate of restenoses and should therefore be discouraged for this indication.

Rate of Decline of GFR and Progression of Vascular Disease in Type 2 Diabetic Patients with Diabetic or Vascular Nephropathy during the Last Three Years before Starting Dialysis Therapy

BACKGROUND

The progression of chronic renal insufficiency depends on the type of primary renal disease and blood pressure (BP) levels. We investigated the rate of decline of glomerular filtration rate (GFR) during 3 years prior to the start of dialysis therapy in type 2 diabetic patients with diabetic nephropathy (dNP) or vascular nephropathy (vNP). The aim of the study was to determine differences in the progression of renal insufficiency and the prevalence of vascular diseases in the two patient groups.

METHODS

In a retrospective study, we investigated type 2 diabetic patients with chronic renal insufficiency who were undergoing regular controls in our outpatient care unit for at least 3 years prior to the start of dialysis. We evaluated only patients who had already died under chronic dialysis therapy, and whose diagnosis of primary renal disease was histologically conformed at autopsy. A total of 40 type 2 diabetic patients were included in the study. Of these, 28 patients had dNP (age 62 +/- 8 years) and 12 had vNP (age 70 +/- 7 years). The following parameters were determined at 3- to 6-month intervals: body weight, BP, HbA1c, serum creatinine (Cr), Cr clearance (Cockroft formula), cholesterol and triglycerides. The prevalence of vascular disease in the two groups was also assessed.

RESULTS

The average decrease in Cr clearance was 7.7 +/- 2.4 ml/min/year in patients with dNP and 7.7 +/- 2.1 ml/min/year in those with vNP (NS). During the entire observation period, mean HbA1c values (7.0 +/- 0.8 vs. 6.8 +/- 0.6%), systolic BP (137 +/- 8 vs. 138 +/- 11 mm Hg) and diastolic BP (86 +/- 4 vs. 87 +/- 7 mm Hg), cholesterol and triglycerides did not differ significantly in the two groups. The prevalence of vascular disease 3 years prior to and at the start of dialysis therapy was similar in patients with dNP and vNP.

CONCLUSION

The progression of dNP and vNP is similar at least during 3 years before the start of dialysis therapy. Vascular risk factors and the prevalence of vascular diseases were not significantly different in the two patient groups. However, diabetic patients with ESRD secondary to dNP were significantly younger than those with vNP.

Factors Influencing the Need for Target Vessel Revascularization After Renal Artery Stenting

PURPOSE

To provide additional insight into factors that may be associated with the need for target vessel revascularization (TVR) following de novo renal artery stenting during long-term follow-up.

METHODS

A retrospective chart and database review was conducted to analyze the progress of all patients with de novo symptomatic renal artery stenosis who underwent stent-supported angioplasty under the auspices of the Single Operator, Single Center, Renal Stent Retrospective Study (SOCRATES). The records review identified 782 patients who were enrolled in the study between 1993 and 2004; after excluding 34 (4.5%) patients (lost to follow-up or inadequate data), 748 consecutive patients (412 women; mean age 70.7+/-9.7 years, range 37-92) were suitable for longitudinal analysis. The need for TVR was based on strict clinical criteria (> or =20% rise in serum creatinine, worsening hypertension, and/or recurrent flash pulmonary edema), and all patients underwent multidisciplinary evaluation before stenting and during follow-up.

RESULTS

Follow-up spanned a mean 45.8+/-26.5 months. TVR was needed in 88 (10.03%) of 877 arteries and was best predicted by patient age < or =67 years (OR 2.91, p=0.0001), stent diameter < or =5.0 mm (OR 2.31, p=0.001), solitary functioning kidney (OR 2.01, p=0.048), history of lower extremity peripheral artery disease (OR 1.87, p=0.008), and antecedent history of stroke (OR 1.73, p=0.026).

CONCLUSION

Renal artery stenting appears to be durable, with only 10% of stented arteries requiring TVR during clinically-based long-term follow-up. Arteries with a final stent diameter < or =5.0 mm were more than twice as likely to need TVR, as were patients with a solitary kidney. The authors acknowledge that clinical recurrence is not a surrogate for ultrasound surveillance after renal artery stenting, so prospective controlled trials will be needed to determine risk factors for restenosis.

Renal artery stenosis: epidemiology, clinical manifestation, and percutaneous endovascular therapy

Renal artery stenosis may cause or deteriorate arterial hypertension and/or renal insufficiency. Technical improvements of diagnostic and interventional endovascular tools have lead to a more widespread use of endoluminal renal artery revascularization and extension of the indications for this type of therapy. Since the first renal artery angioplasties performed by Felix Mahler and Andreas Grüntzig in 1978, numerous single-center studies have reported the beneficial effect of percutaneous transluminal renal angioplasty, and since the early 1990's stenting of renal artery stenosis caused either by atherosclerosis or by fibromuscular dysplasia. This article summarizes the impact of technical improvements of endovascular tools on interventional techniques during the last decade and gives an overview concerning the clinical impact of renal artery revascularization. Despite the absence of sufficient randomized studies, there is nonetheless evidence that stenting of hemodynamically relevant atherosclerotic renal artery stenosis has an impact on blood pressure control, renal function, and left ventricular hypertrophy.

Restenosis after stenting of atherosclerotic renal artery stenosis: Is there a rationale for the use of drug-eluting stents?

Percutaneous stent-angioplasty has become an accepted therapy for the treatment of atherosclerotic renal artery stenosis (RAS) because of higher acute and long-term success rates compared with balloon angioplasty alone. Restenosis rates after successful renal stent placement vary from 6 to 20% and depend mainly on the definition of restenosis and the vessel diameter of the renal artery or stent. We recommend that restenosis should be defined as >70%. The safety and efficacy of drug-eluting stents for the treatment of RAS is poorly defined. The currently partially published GREAT study (Palmaz Genesis peripheral stainless steel balloon expandable stent: comparing a sirolimus-coated vs. a bare stent in REnal Artery Treatment) examined the effect of a sirolimus-coated stent on restenosis rate in 102 patients and found a relative risk reduction of angiographic binary in-stent restenosis by 50% (7% versus 14%, P = ns). Given the lack of outcome data, the considerable expenses associated with drug-eluting stents, morbidity, and cost associated with prolonged dual antithrombotic therapy, the use of drug-eluting stents in RAS should be restricted to clinical trials. This is a review on restenosis rate following renal stenting, its definition, and the potential use for implantation of a drug-eluting stent in RAS, which so far for this indication is not yet commercially available.

Renal artery stenting in solitary functioning kidneys: Technical and clinical results

OBJECTIVE

To evaluate the clinical and technical results of renal artery stenting for the treatment of renovascular hypertension and renal failure in patients with solitary functioning kidney.

MATERIALS AND METHODS

Fifteen patients with solitary functioning kidney underwent renal artery stenting and were followed up for 12-60 months. Before the procedures, systolic and diastolic blood pressures and serum creatinine levels were measured and the number of antihypertensive drugs was recorded and followed up after stenting. In case of restenosis, either in-stent percutaneous transluminal renal angioplasty or stent-in-stent placement was performed.

RESULTS

Primary technical success rate was 100%. One lesion was nonostial while 14 were ostial. Primary patency rates were 100% for 6 months, 92.3% for 12 months, and 69.2% for 24 months. The secondary patency rate at 24 months was 100%. The differences between the baseline and postprocedural values of systolic blood pressures, diastolic blood pressures and the number of antihypertensive drug were statistically significant (P < 0.05), except the values of serum creatinine. Hypertension was cured in 1 (6.7%) patient, improved in 4 (26.6%) and stabilized in 10 (66.7%) patients. Renal function improved in 9 (60%), stabilized in 4 (26.6%), and deteriorated in 2 (13.4%) patients. Minor complication rate was 13.4% and major complication rate was 13.4%.

CONCLUSION

Revascularization of renal artery stenosis using stent in solitary functioning kidneys is a safe and efficient procedure with high primary technical results, low restenosis rates and acceptable complication rates. It has an improving and controlling effect on blood pressure and renal functions.

A simple prediction rule for significant renal artery stenosis in patients undergoing cardiac catheterization

BACKGROUND

Renal artery stenosis (RAS) is a potentially reversible cause of hypertension and renal insufficiency and is associated with poor prognosis.

METHODS

We aimed to identify simple predictors of significant RAS among patients undergoing coronary angiography. Prospective data were collected on 843 consecutive patients who underwent cardiac catheterization and abdominal aortography. Stenoses > or = 75% were considered significant. Multivariable logistic regression was used to assess the relationship between baseline characteristics and coronary anatomy with significant RAS. A simple risk score was derived from the model.

RESULTS

The prevalence of RAS > or = 75% was 11.7%. Independent predictors of significant RAS were older age, higher creatinine levels, peripheral vascular disease, number of cardiovascular drugs, hypertension, female sex, and 3-vessel coronary artery disease or previous coronary artery bypass graft. The concordance index of the model was 0.802. These variables were used to develop a simple predictive score of significant RAS for patients undergoing cardiac catheterization. The prevalence of RAS increased stepwise with increasing score values: 0.6% for a score < or = 5, 1.5% for 6 to 7, 6.1% for 8 to 9, 12.2% for 10 to 11, 18.7% for 12 to 14, 35.7% for 15 to 17, and 62.1% for > or = 18 (P < .001). Approximately one third of the patients had a score > or = 11, which yielded a sensitivity of 76% and a specificity of 71%.

CONCLUSIONS

Renal artery stenosis is a relatively common finding among patients referred for coronary angiography. A simple score can predict the presence of significant RAS among patients referred for cardiac catheterization.

Prospective evaluation of aggressive medical therapy for atherosclerotic renal artery stenosis, with renal artery stenting reserved for previously injured heart, brain, or kidney

Sixty-six patients with atherosclerotic renal artery stenosis (RAS) and serum creatinine < or =2.0 mg/dl were treated with antihypertensive therapy, a statin, and aspirin. Renal stenting was reserved for patients with injuries to the heart, brain, or kidneys. The primary end point was stenotic kidney glomerular filtration rate (GFR) at 21 months; secondary end points included major adverse clinical events, serum creatinine, total GFR, and blood pressure (BP). After baseline evaluation, 26 of 66 patients underwent renal stenting because of injuries to the heart, brain, or kidneys. After 21 months, 6 medical patients required renal stenting, and 5 patients experienced late clinical events (2 medical patients, 3 stent patients). There was no difference in final BP between groups. Whereas medical patients experienced 6% and 8% decreases in total and stenotic kidney GFR, stent patients experienced 7% and 11% increases in total kidney (p = 0.006) and stenotic kidney (p = 0.02) GFR. There was no difference in final serum creatinine. In conclusion, patients with atherosclerotic RAS and baseline creatinine < or =2.0 mg/dl can be safely managed with aggressive medical therapy, with a small decrease in GFR. For patients who develop injuries to the heart, brain, or kidneys, renal artery stenting may further reduce hypertension and improve renal function.

Evaluation of the Safety and Effectiveness of Renal Artery Stenting After Unsuccessful Balloon Angioplasty

OBJECTIVES

This study sought to define the safety and durability of renal stenting after suboptimal/failed renal artery angioplasty in patients with suspected renovascular hypertension.

BACKGROUND

Few prospective multicenter studies have detailed the safety, efficacy, and long-term clinical benefits of renal artery stent revascularization in hypertensive patients with aorto-ostial atherosclerotic renal artery lesions.

METHODS

This non-randomized study enrolled 208 patients with de novo or restenotic > or = 70% aorto-ostial renal artery stenoses, who underwent implantation of a balloon-expandable stent after unsuccessful percutaneous transluminal renal angioplasty (PTRA), which was defined as a > or = 50% residual stenosis, persistent translesional pressure gradient, or a flow-limiting dissection. The primary end point was the nine-month quantitative angiographic or duplex ultrasonography restenosis rate adjudicated by core laboratory analysis. Secondary end points included renal function, blood pressure, and cumulative incidence of major adverse events and target lesion revascularization at 24 months.

RESULTS

The stent procedure was immediately successful in 182 of 227 (80.2%) lesions treated. The nine-month restenosis rate was 17.4%. Systolic/diastolic blood pressure decreased from 168 +/- 25/82 +/- 13 mm Hg (mean +/- standard deviation) at baseline to 149 +/- 24/77 +/- 12 mm Hg at 9 months (p < 0.001 vs. baseline), and 149 +/- 25/77 +/- 12 mm Hg at 24 months (p < 0.001 vs. baseline). Mean serum creatinine concentration was unchanged from baseline values at 9 and 24 months. The 24-month cumulative rate of major adverse events was 19.7%.

CONCLUSIONS

In hypertensive patients with aorto-ostial atherosclerotic renal artery stenosis in whom PTRA is unsuccessful, Palmaz (Cordis Corp., Warren, New Jersey) balloon-expandable stents provide a safe and durable revascularization strategy, with a beneficial impact on hypertension.