Guidelines for the reporting of renal artery revascularization in clinical trials

Drug-coated balloon for treatment of non-atherosclerotic renal artery stenosis-a multi-center study

INTRODUCTION

Renal artery stenosis (RAS) is a significant reason for secondary hypertension. Impaired renal function and subsequent cardiopulmonary dysfunction could also occur. Patients of non-atherosclerotic RAS has a relatively young age and long life expectancy. Revascularization with percutaneous transluminal angioplasty (PTA) is a viable treatment option. However, restenosis is unavoidable which limits its use. Drug-coated balloon (DCB) has been proven to be effective in restenosis prevention in femoropopliteal arterial diseases and in patients with renal artery stenosis. And PTA for Renal artery fibromuscular dysplasia is safe and clinically successful. Therefore, we could speculate that DCB might have potential efficacy in non-atherosclerotic RAS treatment.

METHODS AND ANALYSIS

This will be a randomized multi-center-controlled trial. Eighty-four eligible participants will be assigned randomly in a 1:1 ratio to the control group (plain old balloon, POB) and the experimental group (DCB). Subjects in the former group will receive balloon dilatation alone, and in the latter group will undergo the DCB angioplasty. The DCB used in this study will be a paclitaxel-coated balloon (Orchid, Acotec Scientific Holdings Limited, Beijing, China). Follow-up visits will be scheduled 1, 3, 6, 9, and 12 months after the intervention. Primary outcomes will include controlled blood pressure and primary patency in the 9-month follow-up. Secondary outcomes will include technical success rate, complication rate, and bail-out stenting rate.

TRIAL REGISTRATION

ClinicalTrials.gov (number NCT05858190). Protocol version V.4 (3 May 2023).

Successful Repair of Acute Type B and Retrograde Type A Aortic Dissection With Kidney Ischemia

Acute dissection of thoracic aorta carries a risk of renal ischemia followed by the development of a kidney failure. The optimal surgical and nonsurgical management of these patients, timing of intervention, and the factors predicting renal recovery are not well delineated and remain controversial. We present a case of acute type B thoracic aortic dissection with left kidney ischemia. Evaluation of renal function was performed by the means of internationally accepted Risk, Injury, Failure, Loss of kidney function, End stage kidney disease and Acute Kidney Injury Network classifications for acute kidney injury, renal duplex sonography, and intravascular ultrasound that demonstrated left renal artery dissection with a flap completely compressing the true lumen. The patient underwent thoracic endovascular aortic repair and left renal artery stent and recovered well. Six months later, at the follow-up visit, retrograde type A aortic dissection was found, which was successfully repaired. Reversal of renal ischemia after aortic dissection depends on the precise assessment of renal function and prompt intervention.

The efficacy of renal artery stent combined with optimal medical therapy in patients with severe atherosclerotic renal artery stenosis

OBJECTIVE

To evaluate the efficacy of renal artery stent combined with optimal medical therapy as treatment for renal artery stenosis.

RESEARCH DESIGN AND METHODS

A prospective cohort study was conducted. Patients with severe atherosclerotic renal artery stenosis received percutaneous renal artery stent because of poorly controlled hypertension or preservation of renal function. The patients also received optimal medical therapy to achieve the blood pressure, lipid and blood glucose targets.

MAIN OUTCOME MEASURES

All patients underwent a 12 month follow-up to observe the effect of the procedure on blood pressure control, number of antihypertensive medications and creatinine level.

RESULTS

Stents were placed in 185 renal arteries of 149 patients. Mean stenosis was 83.1 ± 7.0%. The success rate of renal artery stent was 99.3%. At 12 months, estimated glomerular filtration rate increased significantly compared with baseline (84.1 ± 28.8 vs. 76.5 ± 22.50 ml/min ×1.73 m², p < 0.05). Both office blood pressure and 24 hour blood pressure significantly decreased compared with baseline (from 153/83 mmHg to 134/73 mmHg and from 143/80 mmHg to 124/69 mmHg, respectively; p < 0.05), and less antihypertensive medication was taken compared with baseline (1.5 ± 0.8 vs. 2.2 ± 0.9; p < 0.05).

CONCLUSIONS

Renal artery stent combined with optimal medical therapy as a treatment has a beneficial effect on blood pressure control and estimated glomerular filtration rate in selected patients with atherosclerotic renal artery stenosis. Larger studies with a longer follow-up appear necessary to further confirm these intriguing findings.

Approach to atherosclerotic renovascular disease: 2016

The management of atherosclerotic renal artery stenosis in patients with hypertension or impaired renal function remains a clinical dilemma. The current general consensus, supported by the results of the Angioplasty and Stenting for Renal Atherosclerotic Lesions and Cardiovascular Outcomes for Renal Artery Lesions trials, argues strongly against endovascular intervention in favor of optimal medical management. We discuss the limitations and implications of the contemporary clinical trials and present our approach and formulate clear recommendations to help with the management of patients with atherosclerotic narrowing of the renal artery.

Renal artery stent in solitary functioning kidneys: 77% of benefit: A systematic review with meta-analysis

BACKGROUND

Solitary functioning kidney (SFK) is tough issue to address in clinical, mostly developed from renal artery stenosis (RAS) in adults. Although renal artery stent is widely used to help SFK patients, the efficacy of the stent is still disputable. This study is aimed at reviewing a series of SFK cases to draw a conclusion about the efficacy of renal artery stent.

METHODS

All related papers published in PubMed, Web of Science, EMBASE, and Cochrane Library were searched. Studies or subsets were included only if they satisfied certain criteria. The benefit rate which equaled the rate of improvement subjoining the rate of stabilization was calculated. All analyses were conducted with Stata version 12.0 (Stata Corporation, College Station, TX).

RESULTS

According to 7 papers on the efficacy of renal artery stent, 253 SFK patients were included. The result revealed that the renal artery stent could help SFK patients to improve or stabilize their renal function (RF). The benefit rate was 0.77, with 95% confidence interval between 0.72 and 0.83.

CONCLUSIONS

With proper patient selection, renal artery stent could benefit SFK patients with a percentage odd of 0.77 to improve or stabilize the RF.

To Stent or Not to Stent? Update on Revascularization for Atherosclerotic Renovascular Disease

Renal artery stenosis (RAS) is increasingly encountered in clinical practice. The two most common etiologies are fibromuscular dysplasia (FMD) and atherosclerotic renal artery disease (ARAS), with the latter accounting for the vast majority of cases. Significant RAS activates the renin-angiotensin-aldosterone system and is associated with three major clinical syndromes: ischemic nephropathy, hypertension, and destabilizing cardiac syndromes. Over the past two decades, advancements in diagnostic and interventional techniques have led to improved detection and the widespread use of endovascular renal artery revascularization strategies in the management of ARAS. However, renal artery stenting for ARAS remains controversial. Although several studies have demonstrated some benefit with renal artery revascularization, this has not been to the extent anticipated or predicted. Moreover, these trials have significant flaws in their study design and are hampered with inherent bias which make their interpretation challenging. In this review, we evaluate the existing body of evidence and offer an approach to the management of patients with ARAS in light of the current literature. From the data provided, identification of subgroup of patients, namely, those with a hemodynamically significant RAS in the context of progressive renal insufficiency and/or deteriorating arterial hypertension, seems possible and may derive clinical benefit from ARAS stent revascularization. Appropriate patient selection is therefore the key and more robust studies are required.

Diagnostic criteria for renovascular disease: where are we now?

Renovascular disease, especially atherosclerotic renal artery stenosis (ARAS) in older subjects, is commonly encountered in clinical practice. This is at least in part due to the major advances in non-invasive imaging techniques that allow greater diagnostic sensitivity and accuracy than ever before. Despite increased awareness of ARAS, renal revascularization is less commonly performed, likely as a result of several prospective, randomized, clinical trials which fail to demonstrate major benefits of renal revascularization beyond medical therapy alone. Primary care physicians are less likely to investigate renovascular disease and nephrologists likely see more patients after a period of unsuccessful medical therapy with more advanced ARAS. The goal of this review is to revisit current diagnostic and therapeutic paradigms in order to characterize more clearly which patients will likely benefit from further evaluation and intensive treatment of renal artery stenosis.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Noninvasive assessment of transstenotic pressure gradients in porcine renal artery stenoses by using vastly undersampled phase-contrast MR angiography

PURPOSE

To compare noninvasive transstenotic pressure gradient (TSPG) measurements derived from high-spatial- and temporal-resolution four-dimensional magnetic resonance (MR) flow measurements with invasive measurements obtained from endovascular pressure wires with digital subtraction angiographic guidance.

MATERIALS AND METHODS

After Animal Care and Use Committee approval, bilateral renal artery stenosis (RAS) was created surgically in 12 swine. Respiratory-gated phase-contrast vastly undersampled isotropic projection (VIPR) MR angiography of the renal arteries was performed with a 1.5-T clinical MR system (repetition time, 11.4 msec; echo time [first echo], 3.7 msec; 18,000 projection angles; imaging volume, 260 × 260 × 200 mm; acquired isotropic spatial resolution, 1.0 × 1.0 × 1.0 mm; velocity encoding, 150 cm/sec). Velocities measured with phase-contrast VIPR were used to calculate TSPGs by using Navier-Stokes equations. These were compared with endovascular pressure measurements (mean and peak) performed by using fluoroscopic guidance with regression analysis.

RESULTS

In 19 renal arteries with an average stenosis of 62% (range, 0%-87%), there was excellent correlation between the noninvasive TSPG measurement with phase-contrast VIPR and invasive TSPG measurement for mean TSPG (R² = 95.4%) and strong correlation between noninvasive TSPG and invasive TSPG for the peak TSPG measures (R² = 82.6%). The phase-contrast VIPR-derived TSPG measures were slightly lower than the endovascular measurements. In four arteries with severe stenoses and one occlusion (mean, 86%; range, 75%-100%), the residual lumen within the stenosis was too small to determine TSPG with phase-contrast VIPR.

CONCLUSION

The unenhanced MR angiographic technique with phase-contrast VIPR allows for accurate noninvasive assessment of hemodynamic significance in a porcine model of RAS with highly accurate TSPG measurements.

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.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Surgical revascularization of renal artery after complicated or failed percutaneous transluminal renal angioplasty

PURPOSE

The purpose of this study was to evaluate the feasibility and effectiveness of surgical reconstruction of the renal artery after complicated or failed percutaneous transluminal renal angioplasty (PTRA).

METHODS

This was a retrospective study of 45 consecutive patients who were referred to our centers for surgical renal artery reconstruction after 52 complicated or failed PTRA procedures performed between 1980 and 2003. There were 27 women and 18 men, with a median patient age of 28 years (25th percentile, 13.5 years; 75th percentile, 59.5 years). The mean number of PTRA per artery per patient was 1.4 +/- 0.6. Renal artery stenosis was due to arterial fibrodysplasia in 25 patients, atherosclerosis in 17, and inflammatory arteritis in three.

RESULTS

Forty-eight renal artery revascularizations were performed (3 bilateral). The procedure consisted of in situ surgery in 38 patients (79%) and extracorporeal repair in 10 (21%). Primary nephrectomy was required in three patients. One patient did not undergo surgical repair after failed PTRA because of kidney atrophy. Major technical problems were encountered during surgical revascularization in 14 (74%) of the 19 patients treated after complicated PTRA and in four (12%) of the 33 patients treated after failed PTRA. Multiple organ failure led to one death on postoperative day 90 in a patient with atherosclerosis and severe kidney insufficiency. Postoperative thrombosis of the repaired renal artery led to kidney loss in three patients, but only one patient required secondary nephrectomy. Primary patency for the overall series of renal revascularizations was 93.5% +/- 6.5% at 5 years.

CONCLUSION

Surgical reconstruction after complicated or failed PTRA is feasible and effective and allows kidney salvage in most patients. Technical problems during surgical revascularization may require extracorporeal repair in some patients. The results of this study underline the need for careful patient selection and skillful PTRA technique.

Atherosclerotic renovascular disease

Atherosclerotic renovascular disease is a combination of renal artery stenosis and renal ischemia. Blood pressure does not rise until the stenosis is 60% or greater. Disease of both large and small blood vessels is often accompanied by the loss of glomerular filtration rate. Activation of the renin-angiotensin-aldosterone system leads to vasoconstriction and salt retention. Risk factors for atherosclerotic renovascular disease include long-standing hypertension, diabetes, smoking and dyslipidemia. The prevalence of the condition in patients with hypertension resistant to two medications is 20%. As yet, there is no single ideal screening test or evidence-based recommended screening algorithm. Magnetic resonance angiography and computed tomography angiography are noninvasive and have high sensitivity and specificity, but also have high costs associated with them. The captopril renal scan has low sensitivity and specificity in people with renal disease (the population most likely to require the test). Doppler ultrasonography has high sensitivity and specificity in experienced hands, and the renal resistance index, which can easily be added to this test, can identify those with microvascular disease who may not benefit from revascularization. The best determinant of patient outcome is not the degree of renal artery stenosis but the degree of renal parenchymal disease. To date, renal revascularization has not been associated with improved renal survival compared with medical treatment alone. Today, the approach to atherosclerotic renovascular disease is determined by the patient's blood pressure and renal function; possibly, in the future, it will be determined by the result of the renal resistance index as part of a screening algorithm. If the blood pressure is uncontrollable or the renal function is deteriorating, the patient should be considered for renal revascularization initially, with a percutaneous endovascular stent. The management of hypertension involves the use of combinations of antihypertensive agents at doses sufficient to control blood pressure. Medical management also includes aggressive lipid-lowering therapy.

A Study on the Outcome of Percutaneous Transluminal Renal Angioplasty in Patients with Renal Failure

BACKGROUND

The indications for percutaneous transluminal renal angioplasty (PTRA) in renovascular disease, as well as its benefits, remain a matter of debate. The aim of this study was to evaluate the outcome of angioplasty and to identify risk factors associated with less successful outcomes in patients with atheromatous renal artery stenosis and renal failure of varying degrees.

METHODS

The results of PTRA were analyzed retrospectively in 144 patients with serum creatinine levels of >130 micromol/l. Patients were divided into 5 groups according to their indication for angioplasty: (1) deteriorating renal function; (2) accelerating hypertension; (3) a combination of 1 and 2; (4) peripheral vascular disease, and (5) miscellaneous conditions.

RESULTS

The baseline mean (+/- SD) systolic and diastolic blood pressures of the entire group were lowered from 180 +/- 32 and 95 +/- 16 mm Hg to 162 +/- 23 and 86 +/- 12 mm Hg, respectively (p < 0.0005), 12 months after angioplasty. The blood pressure level was unaffected by angioplasty in patients with claudication. The mean number of antihypertensive drugs was reduced in the group with accelerating hypertension from 2.9 +/- 0.8 to 2.4 +/- 1.2 (p = 0.019), and in the group with unilateral renal artery stenosis and two kidneys from 2.4 +/- 1.0 to 1.8 +/- 1.1 (p = 0.002), 12 months after PTRA. Glomerular filtration rate at 3-month follow-up had increased from 23 +/- 11 to 27 +/- 14 ml/min/1.73 m(2) (p = 0.021) in group 1, from 25 +/- 11 to 28 +/- 14 ml/min/1.73 m(2) (p = 0.031) in the combined group of patients consisting of groups 1 and 3, and from 32 +/- 13 to 35 +/- 14 ml/min/1.73 m(2) (p = 0.019) in the group with unilateral renal artery stenosis. No statistically significant difference was found in any of these 3 groups 1 year after angioplasty. The first patient group had an increased prevalence of cardiovascular disease, aortic aneurysm, carotid occlusive disease, and peripheral vascular disease compared to the other patient groups (p < 0.05). Patients with baseline creatinine levels of >300 micromol/l had a lower survival rate at 12, 60, and 120 months after PTRA than patients with serum creatinine levels of <300 micromol/l (p < 0.005). Survival was also lower in patients with bilateral renal artery stenosis and those with a single kidney, compared to patients with a unilateral stenosis at both 5 and 10 years after PTRA (p < 0.05). Regression analysis of predictor variables of mortality rate showed that the relative risk (RR) associated with increased serum creatinine was 4.7 (CI 2.0-11.0; p < 0.0005). The RR for older patients was 1.1 (CI 1.0-1.2; p = 0.008), and the RR for former smokers was 6.0 (CI 1.6-24.0; p = 0.009).

CONCLUSION

The results of the present study indicate that glomerular filtration can be improved in patients who primarily undergo angioplasty to rescue renal function. Renal function with creatinine levels of >300 micromol/l was associated with a lower survival rate. It is, therefore, possible that patients selected after a thorough evaluation of their renal function and comorbid disease factors may benefit from PTRA, even when the indication for angioplasty is to salvage renal function.

Quantitative Vascular Measurements in Arterial Occlusive Disease

Accuracy in quantifying arterial occlusive disease requires an understanding of the relevant technical considerations and familiarity with the strengths and weaknesses of various imaging modalities in this setting. The degree of stenosis is evaluated in terms of diameter stenosis, which can be measured on either projection images or cross-sectional images, or area stenosis, which can be measured only on cross-sectional images. With projection images, the minimum luminal diameter should be sought on multiple images obtained at different angles. The reference site used for measurement should be noted and may be located at the level of the lesion or in a normal-looking portion of the stenotic vessel near the lesion. Multi-detector row computed tomographic (CT) angiography and magnetic resonance (MR) angiography are starting to replace digital subtraction angiography in quantifying arterial occlusive disease. CT angiography allows accurate evaluation without reducing in-plane resolution, although beam-hardening artifacts from high-attenuation structures can degrade image quality. MR angiography is useful even in cases of severe calcification but has a lower spatial resolution. Ultrasonography (US) may also be helpful in quantifying arterial occlusive disease; US analysis is almost always based on blood flow velocity measurement. Precise measurements of stenotic occlusion will help determine optimal therapy for affected patients.

Restenosis in gold-coated renal artery stents

BACKGROUND

Gold coating improves stent visibility under fluoroscopy. This is particularly valuable for precise stent placement during renal artery stenting (RAS). There is conflicting evidence regarding restenosis with gold-coated stents. To evaluate the effect of gold coating on restenosis after renal stenting, we reviewed the results of all patients undergoing RAS in our practice.

METHODS

A retrospective cohort study of all patients undergoing RAS between June 2000 and September 2003 was performed. During this time, both gold-coated and stainless steel stents were used. Restenosis (>60% diameter) was determined by serial follow-up duplex exams (peak systolic velocity >180 cm/s and renal-aortic ratio >3.5). Restenosis rates were determined by using the Kaplan-Meier life-table method. Variables potentially affecting restenosis were evaluated with the log-rank test and Cox proportional hazards modeling.

RESULTS

RAS was performed in 97 arteries (78 patients). Gold-coated (NIRoyal) stents were placed in 59 arteries (48 patients). Stainless steel stents (Corinthian, Genesis, and Herculink) were placed in 38 arteries (34 patients). Patient demographics, indication for treatment, technical success, and complications did not differ between gold and stainless steel stent groups. Mean follow-up was 15 months for gold-coated stents and 18 months for stainless steel stents (NS). By life-table method, 1-year and 2-year freedom from restenosis rates were 84% and 78% in arteries treated with stainless steel stents versus 69% and 39% in those treated with gold-coated stents (P = .012, log-rank test). By multivariate analysis, only the use of gold-coated stents (P = .018; hazard ratio [HR], 3.3; 95% confidence interval [CI], 1.2 to 8.7) and bilateral disease (P = .046; HR, 2.3; 95% CI, 1.02 to 5.2) predicted restenosis. Stent diameter, patient demographics, and indication for RAS had no effect on restenosis by univariate analysis. According to American Heart Association criteria, 87% of patients in the stainless steel group had improved blood pressure at 1 year, compared with 77% in the gold-coated stent group (Kaplan-Meier; P = .042, log-rank test). There were no significant differences in the effect of RAS on serum creatinine levels between the two groups.

CONCLUSION

Gold-coated renal stents had a substantially higher rate of restenosis than stainless steel stents in our series. These findings have led us to abandon the use of gold-coated stents for RAS. Patients who have received gold-coated stents for the treatment of atherosclerotic renal artery stenosis should be followed closely for evidence of restenosis.

Diagnosis and treatment of renovascular hypertension: a cost-benefit analysis

OBJECTIVE

We sought to evaluate and compare the relative cost-benefit of Doppler sonography, MR angiography, and captopril-enhanced renal scintigraphy as techniques for predicting a patient's clinical response to renal angioplasty.

MATERIALS AND METHODS

Estimations of positive and negative predictive values of baseline and captopril-enhanced renal scintigraphy and Doppler sonography examinations for predicting a favorable outcome after renal angioplasty were based on a previously published prospective study involving 74 patients who underwent this treatment. For gadolinium-enhanced MR angiography, predictive values were calculated from a subpopulation of 57 of these 74 subjects. The value of different combined strategies with these techniques for predicting clinical success after angioplasty was evaluated in this population. The costs of investigation and treatment per improved patient were calculated for each imaging technique and for combined strategies in a hypothetic 1,000-patient population with a 30% prevalence of renal artery stenosis, relying on the diagnostic performance reported in the literature for each technique in detecting renal artery stenosis.

RESULTS

The costs for each improved patient were $12,579 for patients selected on the basis of a positive finding on Doppler sonography (false-negative results = 12/1,000) and $10,149 for patients selected with criteria combining a positive finding on Doppler sonography with a bilateral resistive index of less than 0.75 (false-negative results = 32/1,000). Patient selection based on a positive finding on MR angiography cost $18,119 (false-negative results = 0), whereas the cost of patient selection based on a positive finding on renal scintigraphy was $12,939 (false-negative results = 29/1,000).

CONCLUSION

Doppler sonography is more cost-efficient but less sensitive than MR angiography for identifying patients with renovascular hypertension. MR angiography should be favored in hypertensive patients who are resistant to medical therapy to avoid false-negative examinations.

Percutaneous and Open Renal Revascularizations Have Equivalent Long-Term Functional Outcomes

Atherosclerotic renal artery stenosis is a significant cause of poorly controlled hypertension and progressive renal dysfunction leading to ischemic nephropathy and other end-organ damage. The optimal treatment of renovascular disease contributing to hypertension and renal dysfunction is not known. This study compares the anatomic and functional outcomes of both open and endovascular therapy for chronic, symptomatic atherosclerotic renal artery disease. We performed a retrospective analysis of records from patients who underwent renal arterial interventions, endovascular or open bypass, between January 1984 and January 2004. Principal indications for intervention were hypertension (51%), chronic renal insufficiency (13%), and hypertension and elevated creatinine (36%). A total of 247 patients (109 males; mean age 69 +/- 10, range 44-89 years) underwent 314 interventions (109 open procedures; 205 angioplasties, 71% with stent placement). There was a significant difference in 30-day mortality (4% vs. <1%; p < 0.005) between the open and endoluminal groups, but not at 1, 3, or 5 years. Patients in the open group had a higher primary patency rate at 5 years (83 +/- 5% vs. 76 +/- 6%; p = 0.03), but patients in the endoluminal group had a higher assisted primary patency rate at 5 years (92 +/- 5% vs. 84 +/- 5; p = 0.03). There was no significant difference between both treatment groups in cumulative freedom from presenting symptom or in freedom from dialysis and renal-related death. Patients who presented with hypertension were more likely to have shown improvement in their blood pressure with endoluminal intervention at 1, 3, and 5 (59 +/- 6% endoluminal vs. 83 +/- 5% open; p = 0.01) years. From these results we conclude that open repair and endoluminal repair of atherosclerotic renal artery stenosis have similar immediate and long-term functional and anatomic outcomes. Patients who present with hypertension may have greater benefit with an endoluminal repair.

Outcomes of renal artery angioplasty and stenting using low-profile systems

OBJECTIVE

Renal artery percutaneous transluminal angioplasty (RPTA) and stenting (RAS) are accepted therapies for selected patients with renovascular hypertension and chronic renal insufficiency. We evaluated the outcomes and complications of RAS performed by vascular surgeons at our institution with modern low-profile systems.

METHOD

We retrospectively analyzed all RPTA and RAS procedures attempted with the use of low-profile systems from June 2000 to September 2003. Eighty-two patients (96 arteries) with atherosclerotic renal artery stenosis were treated. Indication for treatment was hypertension in 44 (54%) and chronic renal insufficiency in 38 (46%). Technical success, complication rates, clinical success for control of hypertension or renal insufficiency, restenosis, and survival were reviewed with a mean follow-up of 1 year.

RESULTS

Ninety-three arteries were treated with stents, three with RPTA only. Primary technical success was 95%, with 98% overall technical success. Major complications occurred in 6.1% and minor complications in 1.2%. Hypertension was improved in 81% at 1 year. Renal function was improved in 23%, stable in 53%, and worse in 24% at 1 year. Restenosis was seen by routine duplex surveillance in 25% at 1 year. Restenosis associated with clinical deterioration and confirmed by angiogram was seen in 10%. The overall 3-year survival was 83%.

CONCLUSION

RPTA/RAS can be performed with low-profile systems with excellent technical success, low complication rates, and clinical outcomes that compare favorably with prior reports.

Pharmacomechanical Thrombolysis and Early Stent Placement for Iliofemoral Deep Vein Thrombosis

PURPOSE

To evaluate an approach to the treatment of iliofemoral deep vein thrombosis (DVT) that included pharmacomechanical catheter-directed thrombolysis with reteplase and the Helix mechanical thrombectomy device, followed by early stent placement.

MATERIALS AND METHODS

During 3-year period, 23 symptomatic limbs in 18 patients with iliofemoral DVT were treated with reteplase catheter-directed thrombolysis. After an initial infusion of 8 to 16 hours, any residual acute thrombus over a long segment (> 10 cm) was treated by maceration with use of the Helix thrombectomy device. Residual short-segment (< 10 cm) iliac vein thrombus and/or stenosis were treated with stent placement. Technical success, clinical success, complications, thrombolytic infusion time, total thrombolytic agent dose, fibrinogen level changes, and late limb status were retrospectively analyzed.

RESULTS

Technical success was achieved in 23 of 23 limbs (100%). Clinical success was achieved in 22 of 23 limbs (96%). Complete or partial thrombolysis was observed in 19 of 23 limbs (83%). Major bleeding was observed in one patient (6%) and necessitated blood transfusion. Mean per-limb thrombolytic infusion time and total dose were 19.6 hours +/- 8.1 and 13.8 U +/- 5.3 reteplase, respectively. Mean serum fibrinogen nadir and percentage drop in serum fibrinogen were 282 mg/dL +/- 167 and 47% +/- 24%, respectively. Late (mean, 19.8 +/- 11.6 months) modified Venous Disability Scores were 0 (none) for six limbs, 1 (mild) for 10 limbs, 2 (moderate) for two limbs, and 3 (severe) for no limbs.

CONCLUSION

In a preliminary experience, pharmacomechanical catheter-directed iliofemoral DVT thrombolysis with early stent placement was safe and effective.

Divergent outcomes after percutaneous therapy for symptomatic renal artery stenosis

OBJECTIVE

Percutaneous intervention for symptomatic renal artery atherosclerosis is rapidly replacing surgery in many centers. This study evaluated the anatomic and functional outcomes of endovascular therapy for atherosclerotic renal artery stenosis on a combined vascular surgery and interventional radiology service at an academic medical center.

METHODS

This was a retrospective analysis of patients who underwent renal artery angioplasty with or without stenting between January 1990 and June 2002. Indications included hypertension (86%) and rising serum creatinine concentration (55%). One hundred forty-six patients (80 women; average age, 71 years [range, 44-89 years]) underwent 183 attempted interventions (64 to treat bilateral stenosis). Forty-five percent of patients had significant bilateral disease: 27% had greater than 50% bilateral stenosis, and the remainder had nonfunctioning, absent, or occluded vessels.

RESULTS

Of 183 planned interventions, technical success (<30% residual stenosis) was achieved in 179 vessels (98%) with placement of 137 stents (75%). Thirty-day mortality was 0.7%. The major morbidity rate was 4%, and the procedure-related complication rate was 18%. Five-year cumulative patient mortality was 25%. Primary patency, assisted primary patency, and recurrent stenosis rates were 82% +/- 9%, 100% +/- 0%, and 30% +/- 7%, respectively, at 5 years. Within 3 months of the procedure, 52% of patients who received treatment of hypertension demonstrated clinical benefit (hypertension improved or cured), which was maintained in 68% of patients at 5 years. Serum creatinine concentration was lowered or stabilized in 87% of patients within 3 months of the procedure, but this benefit, including freedom from dialysis, was maintained in only 45% of patients at 5 years.

CONCLUSIONS

Endovascular intervention for symptomatic atherosclerotic renal artery stenosis is technically successful. There were excellent patency and low recurrent stenosis rates. There is immediate clinical benefit for most patients, but divergent long-term functional outcomes. Endovascular interventions modestly enhance the care of the patient with hypertension, but poorly preserve long-term renal function in the patient with chronic renal impairment.

Percutaneous Transluminal Renal Angioplasty (PTRA) and Surgical Revascularisation in Renovascular Disease—A Retrospective Comparison of Results, Complications, and Mortality

OBJECTIVE

To evaluate results, complications and mortality following percutaneous transluminal renal angioplasty (PTRA) and open surgical revascularisation for renovascular disease.

METHODS

A retrospective evaluation of 381 renovascular patients (median age 64, range 9-99 years, 152 women) treated at Malmö University Hospital during 1987-1996. Two hundred and sixty-two (69%) of the patients were treated with PTRA, 106 (28%) with open revascularisation.

RESULTS

Thirty-day mortality was 2% in the PTRA group and 9% after open surgery (p<0.001). There were no differences between groups concerning the number of re-do procedures, but first re-do was performed after seven (IQR 3-14) months in the PTRA group, and after 15 (IQR 10-44) months after open revascularisation (p<0.0001). After a median follow-up of 4 months (IQR 0-13) systolic and diastolic blood pressure (BP) had decreased (p<0.0001) in both groups. The number of antihypertensive drugs was reduced (p<0.0001) and S-creatinine levels were unchanged in both groups. Long-time survival assessed with log-rank analysis was better (p<0.01) in the PTRA group. The risk ratio for death with open revascularisation was 1.69 (p<0.01).

CONCLUSIONS

In this retrospective comparison, PTRA was as effective as open revascularisation, with lower complication rate and lower early and long-time mortality, but with shorter time to first re-do.

Endovascular recanalization of the thrombosed filter-bearing inferior vena cava

PURPOSE

To evaluate the authors' preliminary experience with use of endovascular methods to treat inferior vena cava (IVC) thrombosis in patients with IVC filters.

MATERIALS AND METHODS

Catheter-directed thrombolysis, balloon maceration, mechanical thrombectomy, and stent placement were used to treat 10 patients with thrombosis of filter-bearing IVCs causing symptoms in 18 limbs. Procedural challenges, technical and clinical success, complications, postprocedural filter status, and postprocedural pulmonary embolism (PE) prophylaxis were monitored.

RESULTS

Technical and clinical success were achieved in 15 of 18 (83%) and 14 of 18 symptomatic limbs (78%), respectively. Major bleeding (muscular hematoma) occurred in one patient (10%). Postprocedural PE prophylaxis included anticoagulation (n = 8) and placement of a new filter into a newly placed Wallstent (n = 1). During clinical follow-up, no clinically detectable PE was observed. Data pertaining to late limb status were available at a median of 19 months (range 1-46 months) follow-up in seven patients: three patients were asymptomatic, two patients had ambulatory edema only, one patient had constant mild edema, and one patient had constant severe edema. Postprocedural filter stability was radiographically documented at a median of 255 days (range, 4-1021 d) of follow-up.

CONCLUSION

Endovascular recanalization of the occluded IVC is feasible even in the presence of an IVC filter.