Effects of renal artery stent implantation in patients with renovascular hypertension presenting with unstable angina or congestive heart failure

Recurrent Pleural Effusion Associated With Candida Albicans Infection in Transplanted Kidney: A Case Report

Recurrent pleural effusions are associated with significant morbidity and mortality. Pleural effusions are frequently seen in patients with chronic renal failure due to fluid retention. Pleural effusions in renal transplant patients are usually related to secondary pulmonary infections, surgical complications, drug toxicities, or post-transplant lymphoproliferative disorder (PTLD). We describe an unusual cause of recurrent pleural effusion attributed to fungal infection in a transplanted kidney due to activation of the renin-angiotensin-aldosterone system (RAAS), successfully treated with antifungal medications that led to complete resolution of pleural effusion.

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.

Use of percutaneous transluminal renal angioplasty in atherosclerotic renal artery stenosis: a systematic review and meta-analysis

OBJECTIVE

For patients with atherosclerotic renal artery stenosis (ARAS), the role of percutaneous transluminal renal angioplasty (PTRA) remains inconclusive. This study aimed to comparatively evaluate the benefits of best medical therapy (BMT) plus PTRA and BMT alone in treating ARAS.

METHODS

We performed a systematic review and meta-analysis, and searched for all randomized, controlled trials that reported patients with ARAS. The effectiveness and safety in the BMT plus PTRA and BMT alone groups were estimated, taking into account hypertension, stroke, renal events, cardiac events, and mortality.

RESULTS

Nine randomized, controlled trials involving 2309 patients were included. In the BMT plus PTRA group, the incidence of refractory hypertension was significantly lower compared with that in the BMT alone group (odds ratio 0.09; 95% confidence interval 0.01, 0.70). However, there were no significant differences in the rates of stroke, renal events, cardiac events, cardiac mortality, and all-cause mortality between the two groups.

CONCLUSIONS

PTRA plus BMT improves blood pressure in patients with ARAS, but there is insufficient evidence for this therapy in improving stroke, renal events, cardiac events, and cardiac and all-cause mortality.

How should we define appropriate patients for percutaneous transluminal renal angioplasty treatment?

Renovascular hypertension (RVH) is one of the most common causes of secondary hypertension and can result in resistant hypertension. RVH is associated with an increased risk for progressive decline in renal function, cardiac destabilization syndromes including "flash" pulmonary edema, recurrent congestive heart failure, and cerebrocardiovascular disease. The most common cause of renal artery stenosis (RAS) is atherosclerotic lesions, followed by fibromuscular dysplasia. The endovascular technique of percutaneous transluminal renal angioplasty (PTRA) with or without stenting is one of the standard treatments for RAS. Randomized controlled trials comparing medical therapy with PTRA to medical therapy alone have failed to show a benefit of PTRA; however, the subjects of these randomized clinical trials were limited to atherosclerotic RAS patients, and patients with the most severe RAS, who would be more likely to benefit from PTRA, might not have been enrolled in these trials. This review compares international guidelines related to PTRA, reevaluates the effects of PTRA treatment on blood pressure and renal and cardiac function, discusses strategies for the management of RVH patients, and identifies factors that may predict which patients are most likely to benefit from PTRA.

Renal Artery Stenosis in the Patient with Hypertension: Prevalence, Impact and Management

Atherosclerosis is the primary cause of renal artery stenosis. Atherosclerotic renal artery stenosis (ARAS) is associated with three clinical problems: renovascular hypertension, ischemic nephropathy and cardiac destabilization syndrome which pose huge healthcare implications. There is a significant rate of natural disease progression with worsening severity of renal artery stenosis when renal revascularization is not pursued in a timely manner. Selective sub-groups of individuals with ARAS have had good outcomes after percutaneous renal artery stenting (PTRAS). For example, individuals that underwent PTRAS and had improved renal function were reported to have a 45% survival advantage compared to those without improvement in their renal function. Advances in the imaging tools have allowed for better anatomic and physiologic measurements of ARAS. Measuring translesional hemodynamic gradients has allowed for accurate assessment of ARAS severity. Renal revascularization with PTRAS provides a survival advantage in individuals with significant hemodynamic renal artery stenosis lesions. It is important that we screen, diagnosis, intervene with invasive and medical treatments appropriately in these high-risk patients.

When and How Should We Revascularize Patients With Atherosclerotic Renal Artery Stenosis?

Atherosclerotic renal artery stenosis is the leading cause of secondary hypertension and may lead to resistant (refractory) hypertension, progressive decline in renal function, and cardiac destabilization syndromes (pulmonary edema, recurrent heart failure, or acute coronary syndromes) despite guideline-directed medical therapy. Although randomized controlled trials comparing medical therapy with medical therapy and renal artery stenting have failed to show a benefit for renal artery stenting, according to comparative effectiveness reviews by the Agency for Healthcare Research and Quality, the trials may not have enrolled patients with the most severe atherosclerotic renal artery stenosis, who would be more likely to benefit from renal stenting. Because of limitations of conventional angiography, it is critical that the hemodynamic severity of moderately severe (50% to 70%) atherosclerotic renal artery stenosis lesions be confirmed on hemodynamic measurement. The authors review techniques to optimize patient selection, to minimize procedural complications, and to facilitate durable patency of renal stenting. The authors also review the current American College of Cardiology and American Heart Association guidelines and the Society for Cardiovascular Angiography and Interventions appropriate use criteria as they relate to renal stenting.

Renal and Mesenteric Artery Intervention

Atherosclerotic renal artery stenosis is the most common cause of secondary hypertension and may cause progressive renal disease and cardiac destabilization syndromes. Guideline-directed medical therapy is advised in all patients. Patients with refractory symptoms and hemodynamically significant stenoses are more likely to benefit from renal artery stent placement. Chronic mesenteric ischemia (CMI) is an infrequent and difficult to diagnose illness. Due to robust collateralization, clinical symptoms from mesenteric artery stenosis or occlusion is uncommon. Atherosclerosis is the most common etiology of CMI. Current evidence suggests that, compared with open surgical repair, endovascular therapy is the most cost-effective choice for CMI.

Cardiac function response to stenting in atherosclerotic renal artery disease with and without heart failure: results from the Carmel study

Aims

Consensus‐derived guidelines recommend renal stenting for patients with atherosclerotic renal artery disease (ARAD) and heart failure (HF). The aim of this prospective multi‐centre observational study was to verify our hypothesis that changes in E/e′, an echocardiographic correlate of left ventricular (LV) filling pressure, following renal stenting may differ between ARAD patients with and without HF.

Methods and results

This study enrolled de novo ARAD patients undergoing renal stenting at 14 institutions. The primary endpoint was the difference in E/e′ change between ARAD patients with and without HF. Clinical and echocardiographic data were prospectively collected at baseline, the day following renal stenting, and 1 month and 6 months afterwards. ARAD patients with HF were defined as patients with New York Heart Association (NYHA) Class 2 and more, or a history of HF hospitalization. A total of 76 patients were included, and 39% were ARAD patients with HF. ARAD patients with HF had significantly lower estimated glomerular filtration rate (P = 0.028) and higher NYHA functional class (P < 0.001) and Minnesota Living with Heart Failure Questionnaire (MLHFQ) score (P = 0.001) than ARAD patients without HF. Also, ARAD patients with HF had significantly lower LV ejection fraction (P = 0.003) and e′‐velocity (P = 0.003) and higher E/e′ ratio (P = 0.001), left atrial volume index (LAVI) (P = 0.046), LV end‐diastolic volume (LVEDV) (P = 0.001), LV end‐systolic volume (LVESV) (P = 0.001), and LV mass index (P = 0.009) than ARAD patients without HF. All procedures were successful. In contrast to blood pressure and renal function, there was a significant interaction in E/e′ (P_interaction < 0.001) between time and HF, and ARAD patients with HF showed a significant (P < 0.001) decrease in E/e′ albeit those without HF. By the same token, there was a significant interaction in NYHA class (P_interaction < 0.001), MLHFQ score (P_interaction = 0.018), E‐velocity (P_interaction = 0.002), LAVI (P_interaction = 0.001), LVEDV (P_interaction = 0.003), and LVESV (P_interaction = 0.001) between time and HF with a significant improvement in all these variables in ARAD patients with HF (NYHA class, P = 0.001; MLHFQ score, P = 0.002; E‐velocity, P = 0.005; LAVI, P = 0.001; LVEDV, P = 0.017; and LVESV, P = 0.011).

Conclusions

Change in LV filling pressure after renal stenting differed between ARAD patients with and without HF, with a significant improvement in LV filling pressure in patients with HF‐ARAD. These unique findings might support clinical cardiac benefits of renal stenting in ARAD patients with HF.

Recurrent Pleural Effusion as a Result of Bilateral Renal Artery Stenosis. Does Renal Revascularization Help?

Renal artery stenosis (RAS) is the leading cause of secondary hypertension. Renal artery stenosis can result in various cardiopulmonary complications mostly through activation of neurohormonal pathways that result in fluid overload and systemic hypertension. We herein describe a 72-year-old man with recurrent rapidly accumulating transudative pleural effusion in a patient with severe bilateral RAS. Patient pleural effusion resolved following stent placement with revascularization of the left renal artery despite absence of improvement of renal function. Patient renal function continued to decline and ultimately treated with fixed hemodialysis.

Predictors of cardiac benefits of renal artery stenting from a multicentre retrospective registry

OBJECTIVES

There have been limited data regarding the prediction of cardiac benefits after renal artery stenting for patients with atherosclerotic renal artery disease (ARAD). The aim of this multicentre retrospective study was to identify clinical or echocardiographic factors associated with improvements of cardiac symptoms after renal artery stenting.

METHODS

We enrolled 58 patients with de novo ARAD undergoing successful renal artery stenting for heart failure, angina or both between January 2000 and August 2015 at 13 hospitals.

RESULTS

Improvement of cardiac symptoms was observed in 86.2% of patients during a mean follow-up of 6.0±2.7 months. Responders demonstrated significantly lower New York Heart Association functional class, higher estimated glomerular filtration rate, lower serum creatinine and lower interventricular septal wall thickness (IVS), lower left ventricular mass index, lower left atrial dimension and lower E-velocity than non-responders. Backward stepwise multivariate analysis identified IVS as an independent predictor of improvement of cardiac symptoms (OR 0.451, 95% CI 0.209 to 0.976; p=0.043). According to receiver operating characteristic curve analysis, an IVS cut-off of 11.9 mm provided the best predictive value, with sensitivity of 71.4%, specificity of 75.5% and accuracy of 73.5%. The positive predictive value was 74.5% and the negative predictive value was 72.5%.

CONCLUSIONS

This multicentre retrospective study shows that the echocardiographic index of IVS is an independent predictor for improvement of cardiac symptoms after renal artery stenting.

Atherosclerotic renovascular disease - epidemiology, treatment and current challenges

The neutral results of recent large randomized controlled trials comparing renal revascularization with optimal medical therapy in patients with atherosclerotic renovascular disease (ARVD) have cast doubt on the role of revascularization in the management of unselected patients with this condition. However, these studies have strengthened the evidence base for the role of contemporary intensive medical vascular protection therapy and aggressive risk factor control in improving clinical outcomes in ARVD. Patients presenting with ‘high-risk’ clinical features such as uncontrolled hypertension, rapidly declining renal function or flash pulmonary oedema are underrepresented in these studies; hence these results may not be applicable to all patients with ARVD. In this ‘high-risk’ subgroup, conservative management may not be sufficient in preventing adverse events, and indeed, observational evidence suggests that this specific patient subgroup may gain benefit from timely renal revascularization. Current challenges include the development of novel diagnostic techniques to establish haemodynamic significance of a stenosis, patient risk stratification and prediction of post-revascularization outcomes to ultimately facilitate patient selection for revascularization. In this paper we describe the epidemiology of this condition and discuss treatment recommendations for this condition in light of the results of recent randomized controlled trials while highlighting important clinical unmet needs and challenges faced by clinicians managing this condition.

Renal Artery Stenosis: When to Revascularize in 2017

Atherosclerotic renal artery stenosis is the leading cause of secondary hypertension; it can also cause progressive renal insufficiency and cardiovascular complications such as refractory heart failure and flash pulmonary edema. Medical therapy including risk factor modification, renin-angiotensin-aldosterone system antagonists, lipid lowering agents, and antiplatelet therapy is the first line of treatment in all patients. Patients with uncontrolled renovascular hypertension despite optimal medical therapy, ischemic nephropathy, and cardiac destabilization syndromes who have severe renal artery stenosis are likely to benefit from renal artery revascularization. Screening for renal artery stenosis can be done with Doppler ultrasonography, computed tomographic angiography and magnetic resonance angiography. Invasive physiologic measurements are useful to confirm the severity of renal hypoperfusion and therefore improve the selection patients likely to respond to renal artery revascularization. Primary patency exceeds 80% at 5 years and surveillance for in-stent restenosis can be done with periodic clinical, laboratory, and imaging follow-up.

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.

Stents in the Treatment of Renal Artery Stenosis: Long-Term Follow-up

Purpose:

To evaluate the role of percutaneous stenting in the treatment of renal arterial lesions after failure of balloon angioplasty.

Methods:

Two hundred ten patients (139 males; mean age 67.7 ± 9.9 years, range 27 to 87) had 259 balloon-expandable stents (165 Palmaz and 94 Renal Bridge stents) implanted in 244 renal artery stenoses (171 ostial and 73 nonostial lesions). The patients were suffering from intractable hypertension (n = 210) and/or renal dysfunction (n = 48). The majority of the lesions (n = 234) were atheromatous in origin. Stents were implanted for suboptimal balloon dilation (n = 182, 75%), restenotic lesions (n = 27, 11%), or dissection (n = 9, 4%); 26 (11%) ostial lesions were stented primarily. Mean lesion length was 11.9 ± 4.4 mm (range 5 to 30) and mean percent stenosis was 81.9% ± 8.25% (range 70 to 100).

Results:

Immediate technical success was 99% (241 of 244). Three (1.2%) major complications included one intraprocedural stent thrombosis, one arterial perforation manifesting as a perirenal hematoma 24 hours after the procedure, and one renal arterial rupture. Follow-up over a mean 25.4 ± 22.8 months (range 1 to 96) in 185 eligible patients (209 arteries) found 24 cases of restenosis (11.4%). Primary and secondary patencies for all lesions at 60 months were 79% and 98%, respectively, with no significant differences between ostial and nonostial lesions or stent types. Hypertension was reversed in 35 (19%), improved in 112 (61%), and remained unchanged in 37 (20%). Renal function was improved in 29% (14 of 48), unchanged in 67% (32 of 48), and worse in 4% (2 of 48).

Conclusions:

Renal artery stenting is safe, effective, and may be an alternative to surgery, particularly in ostial lesions. Our experience shows reduction in the restenosis rate compared to conventional angioplasty. All ostial stenoses should be stented.

Renovascular heart failure: heart failure in patients with atherosclerotic renal artery disease

Atherosclerotic renal artery disease presents with a broad spectrum of clinical features, including heart failure as well as hypertension, and renal failure. Although recent randomized controlled trials failed to demonstrate renal artery stenting can reduce blood pressure or the number of cardiovascular or renal events more so than medical therapy, increasing attention has been paid to flash pulmonary edema and congestive heart failure associated with atherosclerotic renal artery disease. This clinical entity "renovascular heart failure" is diagnosed retrospectively. Given the increasing global burden of heart failure, this review highlights the background and catheter-based therapeutic aspects for renovascular heart failure.

Emergent unilateral renal artery stenting for treatment of flash pulmonary edema: fact or fiction?

Flash pulmonary edema is characteristically sudden in onset with rapid resolution once appropriate therapy has been instituted (Messerli et al., 2011). Acute increase of left ventricular (LV) end diastolic pressure is the usual cause of sudden decompensated cardiac failure in this patient population. Presence of bilateral renal artery stenosis or unilateral stenosis in combination with a single functional kidney in the susceptible cohort is usually blamed for this condition. We describe a patient who presented with flash pulmonary edema in the setting of normal coronary arteries. Our case is distinct as our patient developed flash pulmonary edema secondary to unilateral renal artery stenosis in the presence of bilateral functioning kidneys. Percutaneous stent implantation in the affected renal artery resulted in rapid resolution of pulmonary edema.

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: epidemiology and treatment

Renal artery stenosis (RAS) is a frequently encountered problem in clinical practice. The disease encompasses a broad spectrum of pathophysiologies and is associated with three major clinical syndromes: ischemic nephropathy, hypertension, and destabilizing cardiac syndromes. The two most common etiologies are fibromuscular dysplasia and atherosclerotic renal artery disease with atherosclerotic disease accounting for the vast majority of cases. Atherosclerotic renovascular disease has considerable overlap with atherosclerotic disease elsewhere and is associated with a poor prognosis. A wide range of diagnostic modalities and treatment approaches for RAS are available to clinicians, and with the advent of endovascular interventions, selecting the best course for a given patient has only grown more challenging. Several clinical trials have demonstrated some benefit with revascularization but not to the extent that many had hoped for or expected. Furthermore, much of the existing data is only marginally useful given significant flaws in study design and inherent bias. There remains a need for further identification of subgroups and appropriate indications in hopes of maximizing outcomes and avoiding unnecessary procedures in patients who would not benefit from treatment. In recent decades, the study of RAS has expanded and evolved rapidly. In this review, we will attempt to summarize the amassed body of literature with a focus on the epidemiology of RAS including prevalence, overlap with other atherosclerotic disease, and prognosis. We will also outline existing diagnostic and treatment approaches available to clinicians as well as summarize the findings of several major clinical trials. Finally, we will offer our perspective on future directions in the field.

Percutaneous renal artery intervention versus medical therapy in patients with renal artery stenosis: a meta-analysis

AIMS

Patients with renal artery stenosis are treated with percutaneous intervention, but randomised studies are inconclusive. We aimed to compare renal percutaneous revascularisation versus medical therapy.

METHODS AND RESULTS

A systematic search for randomised controlled studies yielded three studies comparing renal angioplasty and two studies comparing renal angioplasty with stenting versus medical therapy, respectively. Six sets of data were extracted focusing on systolic and diastolic blood pressure as well as serum creatinine at follow-up. The five trials included 1,030 patients with renal artery stenosis. There was a trend toward, but no significant improvement in, systolic blood pressure (weighted mean difference [WMD] -2.76 mmHg, 95% confidence interval (CI) -5.71 to 0.18; p=0.07), diastolic blood pressure, (WMD -1.18 mmHg, 95% CI -2.69 to 0.32; p=0.12), or serum creatinine (WMD -7.26 mmol/L, 95% CI -14.99 to 0.47; p=0.07) in the patients who underwent percutaneous intervention compared to the medical therapy group. All but one trial showed at least a moderate overall bias risk.

CONCLUSIONS

We did not find a significant improvement in blood pressure or renal function in patients with renal artery stenosis treated with renal artery revascularisation compared to medical therapy alone. However, trial quality was a limitation.

Randomized trials in angioplasty and stenting of the renal artery: tabular review of the literature and critical analysis of their results

As the incidence of hypertension (HTN) continues to rise, finding the optimal treatment of this multifactorial disease is critical. Renal artery stenosis (RAS) is a known etiology for HTN and is associated with declining renal function. Other than medications, the original gold standard for treatment of HTN from RAS was with an open surgical revascularization or nephrectomy. Since then, endovascular interventions for RAS have been reported to be technically possible, but their efficacy over medications or surgery has yielded conflicting results in case series and randomized trials. This tabular review summarizes the results of randomized trials that compared the outcomes of endovascular renal artery interventions with nonendovascular techniques (including medical and surgical treatments) for the treatment of HTN and renal dysfunction. Based on these data, the strengths and weaknesses of individual trials are critically analyzed to better define the methods to identify and treat patients with RAS.

Assessing outcomes to determine whether symptoms related to hypertension justify renal artery stenting

OBJECTIVE

The goal of the study was to determine the blood pressure (BP) response to renal artery stenting (RAS) for patients with hypertension urgency, hypertension emergency, and angina with congestive heart failure (angina/congestive heart failure [CHF]).

METHODS

Patients who underwent RAS for hypertension emergencies (n = 13), hypertension urgencies (n = 25), and angina/CHF (n = 14) were included in the analysis. By convention, hypertension urgency was defined by a sustained systolic BP ≥ 180 mm Hg or diastolic BP ≥ 120 mm Hg, while the definition of hypertension emergency required the same BP parameters plus hypertension-related symptoms prompting hospitalization. Patient-specific response to RAS was defined according to modified American Heart Association reporting guidelines.

RESULTS

The study cohort of 52 patients had a median age of 66 years (interquartile range 58-72). The BP response to RAS varied significantly according to the indication for RAS. Hypertension emergency provided the highest BP response rate (85%), while the response rate was significantly lower for hypertension urgency (52%) and angina/CHF (7%; P = .03). Only 1 of 14 patients with angina/CHF was a BP responder. Multivariate analysis showed that hypertension urgency or emergency were not independent predictors of BP response to RAS. Instead, the only independent predictor of a favorable BP response was the number of preoperative antihypertensive medications (odds ratio 7.5; 95% confidence interval 2.5-22.9; P = .0004), which is another indicator of the severity of hypertension. Angina/CHF was an independent predictor of failure to respond to RAS (odds ratio 118.6; 95% confidence interval 2.8-999.9; P = .013).

CONCLUSIONS

Hypertension urgency and emergency are clinical manifestations of severe hypertension, but the number of preoperative antihypertensive medications proved to be a better predictor of a favorable BP response to RAS. In contrast, angina/CHF was a predictor of failure to respond to stenting, providing further evidence against the practice of incidental stenting during coronary interventions.

Atherosclerotic renal artery stenosis: review of pathophysiology, clinical trial evidence, and management strategies

Renal artery stenosis is prevalent and commonly encountered by cardiovascular specialists. Recently published randomized studies have provoked tremendous controversies in the treatment strategy with regard to renal artery stenting. However, these studies are inconclusive because of major study limitations. As such, cardiovascular specialists are uncertain of the indications or utility of renal revascularization, with differing opinions on management by nephrologists and cardiologists. A greater understanding of this disease process, especially with regard to its functional significance and consequence and treatment strategies based on well-designed clinical trials, is sorely needed. Our review focuses on atherosclerotic renal artery stenosis, with an emphasis on indications for revascularization and review of current trial data.

Cardiac benefits of renal artery stenting

AIMS

The aims of this study were to evaluate the effects of renal stenting on cardiac function using echocardiographic parameters, and to clarify whether changes in clinical and echocardiographic variables after renal stenting differ between atherosclerotic renal artery stenosis (ARAS) patients with and without cardiac symptoms.

METHODS AND RESULTS

A total of 61 patients who underwent renal stenting and echocardiography were included in the study. Left ventricular (LV) filling pressure and LV relaxation were evaluated with tissue Doppler imaging. The ratio of the peak early diastolic mitral inflow velocity to the peak early mitral annular velocity (E/e' ratio) and the e'-velocity were measured to assess diastolic function. LV ejection fraction remained unchanged, but the E/e' ratio (P<0.001) and the e'-velocity (P=0.004) improved after renal stenting. In particular, the E/e' ratio improved from 13.7±5.6 to 11.9±4.0 (P=0.002) within 24 hours after renal stenting and remained low at 11.2±3.8 after a mean follow-up period of 7±4 months (P=0.001). Patients with cardiac symptoms showed significantly better change in E/e' ratio (P=0.002) and E-velocity (P=0.005) compared to those without cardiac symptoms. Cardiac symptoms also significantly improved after renal stenting (New York Heart Association functional class: 2.5±0.6 at baseline to 1.4±0.6 at follow-up; P<0.001).

CONCLUSIONS

Renal stenting improved echocardiographic parameters that reflect LV diastolic function, and yielded a higher benefit for E/e' ratio and E-velocity in patients with cardiac symptoms than in those without cardiac symptoms.

Efficacy of renal revascularization in a patient with fibromuscular renal artery stenosis and heart failure

We report the case of a 65-year-old woman with a solitary kidney who developed hypertension due to renal artery stenosis caused by fibromuscular dysplasia. In addition, an echocardiogram revealed severe left ventricular systolic and diastolic dysfunction. Despite antihypertensive drug treatment that included diuretics, her serum concentration of brain natriuretic peptide was persistently elevated and associated with progressive worsening of renal function. She underwent iliac artery to renal artery bypass grafting. After the surgery, blood pressure control was good, the serum concentration of brain natriuretic peptide decreased, and left ventricular diastolic function improved. This case exemplifies the efficacy of renal revascularization in patients with fibromuscular renal artery stenosis and heart failure.

Primary stenting for atherosclerotic renal artery stenosis

INTRODUCTION

Endovascular treatment for atherosclerotic renal artery stenosis (ARAS) was first performed >30 years ago and its use has increased rapidly since then. However, only recently have large randomized trials rigorously evaluated its clinical benefit.

METHODS

We systematically reviewed the controlled studies on primary stenting for atherosclerotic renal artery stenosis. Studies were included if they compared the outcome of stenting with other treatments, or the outcome associated with different stent characteristics or stenting methods.

RESULTS

Stenting is preferred over angioplasty alone and over surgery when revascularization is indicated for ostial ARAS, except in cases of coexistent aortic disease indicating surgery. Randomized controlled trials showed no significant benefit and substantial risk of renal artery stenting over medication alone in patients with atherosclerotic ARAS without a compelling indication. Improvements in the procedure, such as with distal embolic protection devices and coated stents, are not associated with better clinical outcomes after stent placement for ARAS.

CONCLUSION

Recent evidence shows that impaired renal function associated with ARAS is more stable over time than previously observed. Optimal medical treatment should be the preferred option for most patients with ARAS. Only low-level evidence supports compelling indications for revascularization in ARAS, including rapidly progressive hypertension or renal failure and flash pulmonary edema.

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.

Epidemiology and natural history of atherosclerotic renovascular disease

Atheromatous renovascular disease (ARVD) is increasingly suspected and diagnosed, and it commonly presents to several different clinical specialties. In this review, the epidemiology, risk factors, comorbid disease associations, natural history, and prognosis of ARVD is described. Atheromatous renovascular disease is strongly associated with macrovascular pathology in other important vascular beds, especially the coronary, aortoiliac and iliofemoral circulations, and also with structural and functional heart disease. These clinicopathologic relationships contribute to the high morbidity and mortality associated with the condition. Understanding of the natural history of renal artery stenosis may enable intensified treatment strategies to reduce associated risk and improve patient prognosis.

Experience of stenting for atherosclerotic renal artery stenosis in a cardiac catheterization laboratory: technical considerations and complications

BACKGROUND

Atherosclerotic renal artery (RA) stenosis contributes to hypertension, renal insufficiency and end stage renal disease, and is independently associated with adverse cardiovascular events. Percutaneous renal intervention is efficacious in treating renovascular hypertension and may be effective in stabilizing or improving renal function, thereby reducing cardiovascular risk. However, high rates of procedural complications have been reported.

OBJECTIVES

To determine the nature and frequency of complications of percutaneous renal intervention using contemporary techniques and equipment in a high-volume cardiac catheterization laboratory.

METHODS

Consecutive patients undergoing attempted RA stenting for atherosclerotic RA stenosis in the cardiac catheterization laboratory at the Vancouver General Hospital (Vancouver, British Columbia) between June 2000 and March 2007 were enrolled in a prospective registry. Baseline clinical characteristics, procedural and technical information, and complications were recorded.

RESULTS

A total of 132 RAs were stented in 106 patients during 108 procedures. The procedural success rate was 100%, with no related death, myocardial infarction, nephrectomy or dialysis. Major complications included three pseudoaneurysms (2.8%) and acute deterioration in renal function in six patients (5.5%), although renal function returned to baseline in one patient at 12 months.

CONCLUSIONS

RA stenting can be successfully and safely performed using contemporary techniques, and the low complication rates described should be the minimum standard for contemporary trials evaluating RA stenting.

Atherosclerotic renal artery stenosis: current therapy and future developments

Atherosclerotic renal artery stenosis affects between 2 and 4 million people in the United States alone and likely has a higher prevalence than previously thought. Renal artery stenosis has been increasingly recognized in recent years, especially in patients with cardiovascular disease. It has been associated with hypertension, renal dysfunction, and sudden onset of pulmonary edema. Patients with symptomatic and hemodynamically significant renal artery stenosis are candidates for revascularization. Revascularization is most often accomplished by renal artery stenting, which has high success rates in terms of patency and low complication rates. An important element in managing patients with renal artery stenosis is selecting those patients who are most likely going to benefit from revascularization. This review article focuses on the clinical diagnosis, current treatment options, and future directions regarding treatment of patients with renal artery stenosis.

Diagnosis and management of atherosclerotic renal artery stenosis: improving patient selection and outcomes

Renal artery stenosis (RAS) is common among patients with atherosclerosis, and is found in 20-30% of individuals who undergo diagnostic cardiac catheterization. Renal artery duplex ultrasonography is the diagnostic procedure of choice for screening outpatients for RAS. Percutaneous renal artery stent placement is the preferred method of revascularization for hemodynamically significant RAS, and is favored over balloon angioplasty alone. Stent placement carries a class I recommendation for atherosclerotic RAS according to ACC and AHA guidelines. Discordance exists between the very high (>95%) procedural success rate and the moderate (60-70%) clinical response rate after renal stent placement, which is likely to be a result of poor selection of patients, inadequate angiographic assessment of lesion severity, and the presence of renal parencyhmal disease. Physiologic lesion assessment using translesional pressure gradients, and measurements of biomarkers (e.g. brain natriuretic peptide), or both, could enhance the selection of patients and improve clinical response rates. Long-term patency rates for renal stenting are excellent, with 5-year secondary patency rates greater than 90%. This Review will outline the clinical problem of atherosclerotic RAS and its diagnosis, and will critically assess treatment options and strategies to improve patients' outcomes.

Broken pump or leaky filter? Renal dysfunction in heart failure a contemporary review

Renal dysfunction is a frequent and progressive complication of chronic heart failure and is a powerful predictor of cardiovascular mortality. It is intimately associated with cardiovascular disease even in its earliest stages. Although cardiovascular and renal disease share many risk factors, the prognostic implications do not simply reflect widespread atherosclerotic vascular disease as this appears to be as important in those with heart failure secondary to idiopathic dilated cardiomyopathy as it is in those with coronary artery disease. There may be a role in the progression of heart failure, as the deleterious effects of even "mild" renal impairment seem to be borne out in predicting outcome, in a broad range of heart failure patients including those with heart failure and preserved systolic function. Renal dysfunction is both an indication for, as well as frequently limiting intervention with intensive disease modifying therapy. Although renal impairment is common in heart failure and these patients are at higher risk for adverse events including death, they are under represented in clinical trials.

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.

Interventional therapies for heart failure in the elderly

The aging of a population replete with risk factors for heart failure (HF) (coronary heart disease, diabetes, and hypertension) coupled with a declining age-adjusted mortality rate for coronary artery and hypertensive heart diseases has created, and will continue to create, a literal explosion in the prevalence of HF in the United States. Despite advances in maximal medical therapy, however, most patients who have symptomatic HF can expect functional impairment, interludes of worsening symptomatology, and a shortened lifespan. This article updates the use of interventional therapies for the treatment of elderly patients who have HF caused by coronary artery disease, valvular heart disease, congenital heart disease, myocardial disease, and renal vascular disease.

Renal Artery Stenosis and Cardiovascular Risk

Atherosclerotic renal artery stenosis is the most common disease of the renal arteries and may lead to ischemic renal disease and hypertension. A close relationship exists between renal and cardiovascular disease, as they often occur concomitantly, and abnormalities in either system can cause disease and determine clinical outcome in the other. Renovascular disease is gaining recognition as a potentially important risk factor for cardiovascular morbidity and mortality. This article explores the association between atherosclerotic renal artery stenosis and the cardiovascular system.

Interventional therapies for heart failure in the elderly

The aging of a population replete with risk factors for heart failure(HF) (coronary heart disease, diabetes, and hypertension) coupled with a declining age-adjusted mortality rate for coronary artery and hypertensive heart diseases has created, and will continue to create, a literal explosion in the prevalence of HF in the United States. Despite advances in maximal medical therapy, however, most patients who have symptomatic HF can expect functional impairment, interludes of worsening symptomatology, and a shortened lifespan. This article updates the use of interventional therapies for the treatment of elderly patients who have HF caused by coronary artery disease, valvular heart disease, congenital heart disease, myocardial disease, and renal vascular disease.

Safety of Angiotensin-Converting Enzyme Inhibitors in Patients with Bilateral Renal Artery Stenosis Following Successful Renal Artery Stent Revascularization

Angiotensin-converting enzyme inhibitors (ACEIs) are contraindicated in patients with bilateral renal artery stenosis due to risk of azotemia resulting from preferential efferent arteriolar vasodilation in the renal glomerulus due to inhibition of angiotensin II. Patients with renal artery stenosis who can derive survival benefit from ACE inhibition, therefore, may not receive ACEI therapy. We evaluated the safety of ACEI therapy in patients with bilateral renal artery stenosis following successful revascularization using renal artery stenting. This study is a retrospective analysis of 25 patients who underwent bilateral renal artery stenting for refractory hypertension and had a strong clinical indication for long-term ACEI use (left ventricular dysfunction or diabetes). Eighteen of the 25 patients (72%) have been safely maintained on a target dose of ACEIs, 2 of the 25 have been treated with angiotensin receptor blockers due to cough, and 5 of the 25 are being treated with a hydralazine/nitrate combination due to cough (2 patients) or baseline renal insufficiency (3 patients). We conclude that patients with bilateral renal artery stenoses that have been successfully revascularized using renal stenting may be safely treated with long-term ACEI therapy.