Stenting for atherosclerotic renal artery stenosis: one poorly designed trial after another

Contrast-Enhanced Ultrasound Assessment of Renal Parenchymal Perfusion in Patients with Atherosclerotic Renal Artery Stenosis to Predict Renal Function Improvement After Revascularization

Background

Identifying patients with atherosclerotic renal artery stenosis (ARAS) who will be improved in renal function after percutaneous transluminal renal artery stenting (PTRAS) is crucial since most patients show no worthwhile benefit of PTRAS. Although the assessment of renal parenchymal perfusion is useful for the identification, few studies predict the renal functional improvement by evaluating the characteristics of renal perfusion.

Objective

The aim of this study was to assess the renal parenchymal perfusion in ARAS patients with contrast-enhanced ultrasonography (CEUS) and predict the benefits of renal function after PTRAS utilizing time-intensity curve (TIC) parameters.

Methods

Thirty-eight kidneys in 30 ARAS patients received PTRAS in this study. They were divided into moderate stenosis group (n=25) and severe stenosis group (n=13) and mild dysfunction group (n=14) and moderate dysfunction group (n=24) according to the degree of renal stenosis and radioisotope glomerular filtration rate (rGFR). The baseline assessment of renal function and renal parenchymal perfusion were performed for all patients. rGFR was repeated to evaluate the renal outcome at 4 months after PTRAS. The outcome of PTRAS was classified as improved, stable, or deteriorated compared to the baseline. Time-intensity curve (TIC) parameters obtained from CEUS were analyzed to evaluate the predictive accuracy.

Results

TIC parameters (AUC and PI) were positively correlated with renal function (r=0.617, 0.663; P<0.05) but weakly and negatively correlated with the stenosis (r=−0.360, −0.435; P<0.05). Baseline rGFR was not accurate in predicting improved renal function after PTRAS (0.670). The accuracy of the combined prediction model of baseline AUC and PI (0.889) was higher than the individual indicators (baseline AUC: 0.855 and PI: 0.782).

Conclusion

CEUS could accurately assess renal parenchymal perfusion and identify ARAS patients with potential benefit after PTRAS. The combination of TIC parameters (AUC and PI) is valuable in the prediction of improved renal function after PTRAS.

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.

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.

Transradial Peripheral Arterial Procedures

Increased understanding and increased adoption of transradial catheterization across the world have led to further exploring of radial artery access for transradial endovascular interventions in peripheral artery disease (PAD). This article discusses the advantages and limitations of the transradial approach for endovascular medicine by using case examples, illustrations, and videos. The details about how to use a radial approach for PAD intervention, including and tips tricks, are discussed.

Treatment of hypertension in patients with atherosclerotic renal artery stenosis, updated

Atherosclerotic renal artery stenosis (ARAS) is a fairly common disease of elderly patients and is discovered incidentally in 6.3% to 38% in those undergoing diagnostic cardiac or abdominal angiography. Of those patients diagnosed with renal artery stenosis, in 90% it is due to ARAS and in 10% to fibromuscular dysplasia (FMD), which is a disease of younger persons, mostly females. Renal artery stenosis is frequently associated with hypertension and impaired renal function, and it is perceived by many physicians as the primary cause of hypertension and renal failure. For this reason, they believe that hypertension and renal failure can be significantly improved by performing percutaneous transluminal renal angioplasty (PTRA) with a stent placement as the preferred treatment instead of medical therapy. This practice has led to an increase in angioplasties, especially by interventional cardiologists who are familiar with the procedure. However, the results of several randomized studies comparing interventional therapy with medical therapy have shown no significant difference between the 2 treatment modalities in blood pressure reduction and prevention and in worsening of renal function. Similar results have been found by nonrandomized trials in patients treated selectively with PTRA. For this review, a Medline search was conducted of the English-language literature from January 1, 2006 to December 31, 2013, using the terms atherosclerotic renal artery stenosis and renal artery stenosis; 6 pertinent randomized studies were selected. These studies, with collateral literature, are discussed in this review. The data show that PTRA with stent plus medical therapy in patients with ARAS is not superior to medical therapy alone in lowering the blood pressure, in preventing renal function deterioration, and in reducing all-cause mortality, cardiovascular morbidity or mortality, and strokes.

Where and when device therapy may be useful in the management of drug-resistant hypertension

Device therapy for the treatment of uncontrolled and resistant hypertension has evolved significantly over the past several decades. Both renal artery disease and sympathetic hyperactivity have been linked to resistant hypertension. This manuscript will review the current evidence base supporting device therapy (e.g., renal artery revascularization, sympathetic nervous system modulation) for resistant hypertension.

Transcatheter therapies for resistant hypertension: Clinical review

Resistant hypertension (RHTN) is a commonly encountered clinical problem and its management remains a challenging task for healthcare providers. The prevalence of true RHTN has been difficult to assess due to pseudoresistance and secondary hypertension. Atherosclerotic renal artery stenosis (RAS) has been associated as a secondary cause of RHTN. Initial studies had shown that angioplasty and stenting for RAS were a promising therapeutic option when added to optimal medical management. However, recent randomized controlled trials in larger populations have failed to show any such benefit. Sympathetic autonomic nervous system dysfunction is commonly noted in individuals with resistant hypertension. Surgical sympathectomy was the treatment of choice for malignant hypertension and it significantly improved mortality. However, post-surgical complications and the advent of antihypertensive drugs made this approach less desirable and it was eventually abandoned. Increasing prevalence of RHTN in recent decades has led to the emergence of minimally invasive interventions such as transcatheter renal denervation for better control of blood pressure. It is a minimally invasive procedure which uses radiofrequency energy for selective ablation of renal sympathetic nerves located in the adventitia of the renal artery. It is a quick procedure and has a short recovery time. Early studies in small population showed significant reduction in blood pressure. The most recent Symplicity HTN-3 study, which is the largest randomized control trial and the only one to use a sham procedure in controls, failed to show significant BP reduction at 6 mo.

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.

Blood pressure response to renal artery stenting in 901 patients from five prospective multicenter FDA-approved trials

BACKGROUND

Renal artery stent revascularization is commonly used for renovascular hypertension. Clinical predictors associated with blood pressure (BP) improvement after renal artery stent revascularization are not well understood.

METHODS

Patient-level data from 901 patients in five prospective multicenter Food and Drug Administration-approved investigational device exemption studies of renal artery stent revascularization was pooled. BP response was defined as reduction of systolic BP (SBP) by >10 mm Hg. Stent patency was defined within each study. Associations of BP reduction were determined by logistic regression.

RESULTS

Of 901 patients, complete outcome information was available in 527. Of these, 212/527 (40%) were male, mean age was 63 ± 13 years, 196/544 (36%) were diabetic and 504/527 (96%) had a SBP ≥ 140 mm Hg or DBP ≥ 90 mm Hg at baseline. Compared to baseline, 9-month systolic (164 ± 21 mm Hg vs. 146 ± 22 mm Hg, P < 0.0001) and diastolic (79 ± 13 mm Hg vs. 76 ± 12 mm Hg, P < 0.0001) BP declined significantly. Nine-month stent patency was 90% (305/339). In a univariate analysis, baseline SBP >150 mm Hg (OR = 4.09, CI = 2.74-6.12, P < 0.0001) was positively associated with BP response following renal artery stent revascularization. In a multivariable analysis, baseline SBP remained associated with a positive BP response (OR = 1.76, CI = 1.53-2.03, P < 0.0001).

CONCLUSIONS

In the largest pooled dataset of patients treated with renal artery stent revascularization, SBP and DBP were significantly lower at 9-months. Elevated baseline SBP (>150 mm Hg) was strongly associated with BP reduction after the procedure.

Management of patients with resistant hypertension: current treatment options

Resistant hypertension (RHTN) is an increasingly common clinical problem that is often heterogeneous in etiology, risk factors, and comorbidities. It is defined as uncontrolled blood pressure on optimal doses of three antihypertensive agents, ideally one being a diuretic. The definition also includes controlled hypertension with use of four or more antihypertensive agents. Recent observational studies have advanced the characterization of patients with RHTN. Patients with RHTN have higher rates of cardiovascular events and mortality compared with patients with more easily controlled hypertension. Secondary causes of hypertension, including obstructive sleep apnea, primary aldosteronism, renovascular disease, are common in patients with RHTN and often coexist in the same patient. In addition, RHTN is often complicated by metabolic abnormalities. Patients with RHTN require a thorough evaluation to confirm the diagnosis and optimize treatment, which typically includes a combination of lifestyle adjustments, and pharmacologic and interventional treatment. Combination therapy including a diuretic, a long-acting calcium channel blocker, an angiotensin-converting enzyme inhibitor, a beta blocker, and a mineralocorticoid receptor antagonist where warranted is the classic regimen for patients with treatment-resistant hypertension. Mineralocorticoid receptor antagonists like spironolactone or eplerenone have been shown to be efficacious in patients with RHTN, heart failure, chronic kidney disease, and primary aldosteronism. Novel interventional therapies, including baroreflex activation and renal denervation, have shown that both of these methods may be used to lower blood pressure safely, thereby providing exciting and promising new options to treat RHTN.

Cranio-caudal (transradial) approach for renal artery intervention

This report describes the technique of transradial renal angiography and interventions. We illustrate the approach using typical case images. We believe cranio-caudal approach to the renal artery for diagnostic and therapeutic catheterization offers advantages over the traditional femoral approach.

Percutaneous renal artery angioplasty and stenting: indications, technique and results

BACKGROUND

Percutaneous interventions for renal arterial disease can be used to treat a variety of conditions including both atherosclerotic and non-atherosclerotic renal artery stenosis (RAS) as well as endovascular management of renal artery aneurysms (RAA).

AIM

We sought to examine the indications, techniques and results of percutaneous renal angioplasty and stenting in our institution over a 6-year period and review the current evidence for practice.

METHODS

Patient demographics, procedure indications, technical procedural details, complications, baseline and follow-up renal profile indices were analysed.

RESULTS

The most common indication for intervention was atherosclerotic RAS (69.2%) followed by RAS secondary to fibromuscular dysplasia (15.3%) and RAA (15.3%). There was a 100% technical success in our cohort of patients. The majority of patients (84.6%) had cross-sectional imaging in the form of computed tomography or magnetic resonance angiography prior to intervention.

CONCLUSION

When performed in appropriate settings following close liaison with referring physicians, percutaneous renal angioplasty and stenting remains an important treatment modality for renovascular disease.