Progression Of Renal Artery Stenosis Research Articles

ASSOCIATION OF RENAL ARTERY STENOSIS WITH CORONARY ARTERY DISEASE IN HYPERTENSIVE PATIENTS: A CROSS SECTIONAL STUDY

Objectives: To determine the association between Renal artery stenosis (RAS) and coronary artery disease (CAD), and to compare this with normotensive and non CAD patients.Materials and Methods: This was a cross sectional study, conducted at Radiology/Cardiology departments of Mardan Medical Complex (MMC), Mardan. Normotensive patients and hypertensive patients both were included in this study while those patients with known kidney disease were excluded from the study.Results: A total 90 patients were included in study having mean mean age of 45.5 ± 13. RAS-CAD association was evaluated by several parameter in both normotensive and hypertensive patients. The independent t-test among coronary artery disease and renal artery revealed a significant association (p=0.001).Conclusion: The study concluded that progression of Renal Artery Stenosis (RAS) had a strong association with development of coronary artery disease (CAD).

4. Safety of Renal Denervation as Treatment for Resistant Hypertension: A Systematic Review

Hypertension is very common throughout the world's population, which many people are unaware of, but it is still rising in population and causing a major public health problem. One of the methods used in treating resistant hypertension is renal denervation. However, studies on its safety and vascular complications effects are still unknown. The purpose of this study was to find out the safety of renal denervation in patients with resistant hypertension. This review was conducted on 10–17 December 2022. Two independent researchers systematically extracted data from several databases, such as PubMed Central (PMC), Science Direct, and PUBMED by using MeSH terminology of keywords renal denervation, hypertension, and safety. The extracted studies were then analyzed and selected according to our inclusion criteria such as studies in the last 5 years, cohort studies, and case-control studies. We excluded systematic reviews, meta-analyses, case series, case reports, studies on pregnant women, children, and animals. Research quality was assessed using Newcastle-Ottawa (NOS). From 4 cohort studies (166 subjects from various countries), 3 of them showed renal denervation has a favorable safety profile in gaining blood pressure control. The safety endpoint such as all-cause death and vascular complication were reached, but one study reported one patient with progression of renal artery stenosis and hypertensive urgency; All studies have proven good quality based on NOS. In conclusion, renal denervation showed efficacy by sustained blood pressure reducing effect in patients with resistant hypertension. However, further study is needed to confirm these findings.

PS-R04-2: A CASE OF SUCCESSFUL PERCUTANEOUS TRANSLUMINAL RENAL ANGIOPLASTY (PTRA) FOR RENAL ARTERY STENOSIS ASSOCIATED WITH TAKAYASU'S ARTERITIS

Introduction: In Japan, renal vascular hypertension based on renal artery stenosis (RAS) accounts for 1% of all hypertensive patients, and RAS is present in approximately 10% of autopsy cases of coronary artery disease and cerebrovascular disease. As ischemic nephropathy and complications of cardiovascular disease (CVD) due to RAS are common, early diagnosis and treatment for RAS is important. However, results of several large clinical trials have not shown the efficacy of percutaneous transluminal renal angioplasty (PTRA) for atherosclerotic RAS. Case: 51-year-old woman who diagnosed as Takayasu's arteritis (TA) 35 years ago, had been treated with 5 mg daily of prednisone. She presented with hypertension and edema in both legs a year before admission. Her examination at that time revealed increased serum creatinine from 1.0 to 1.7 mg/dL, high proteinuria (7.3 g/gCr), high renin activity (47.0 ng/mL/hr) and right RAS. Eight months before admission, she had an operation for ruptured descending aorta. She had recurrent episodes of dyspnea on exertion, worsening leg edema and severe hypertension and was admitted to the hospital for the treatment. Clinical course: In addition to severe hypertension (190/80 mmHg) and progression of RAS, she had pulmonary congestion, high brain natriuretic peptide (BNP) level (1149.5 pg/mL), increasing creatinine levels (Cr 3.1 mg/dL), and left non-functioning kidney on admission. Despite taking 8 types of antihypertensive drugs and diuretics without renin-angiotensin system inhibitors, blood pressure and fluid retention were poorly controlled, and thus we decided to perform PTRA for the right RAS. After the PTRA, edema, hypertension and pleural effusion had been dramatically improved. In addition, we could observe decrease of serum creatinine (Cr 1.6 mg/dL), proteinuria (0.5 g/gCr) and plasma renin activity (1.9 ng/mL/hr). Therefore, we reduced the antihypertensive drugs from 8 to 2. Discussions: Although the benefit of PTRA for RAS associated with TA remains unclear, the clinical course suggests that the success of PTRA in this case may be related to the fact that the RAS was complicated by TA. It also suggests that we should consider PTRA in cases of hypertension and pulmonary congestion associated with RAS which are difficult to control like this case. Conclusion: We have experienced a case of RAS associated with TA that was successfully treated with PTRA.

Value of contrast-enhanced ultrasound for diagnosis and follow-up of renal artery stenosis in patients with chronic kidney disease.

To evaluate whether contrast-enhanced ultrasound (CEUS) is an accurate, non-nephrotoxic diagnostic method and follow-up tool for use in patients with chronic kidney disease (CKD) and renal artery stenosis (RAS). In this prospective and monocentric study, we compared the sensitivity and specificity of CEUS for the diagnosis of RAS in CKD patients, using digital subtraction angiography (DSA) or computed tomographic angiography (CTA) as the gold standard methods. Further, the value of CEUS for distinguishing restenosis from other diseases was assessed. The ultrasound physicians conducted the examinations and served as the CEUS report readers who were blinded to the DSA or CTA results. Patients with RAS (n = 60) were enrolled. Average patient age was 64.4 ± 18.0years and median estimated glomerular filtration rate was 66.1mL/min/1.73 m2. CEUS was used to image 94 stenotic renal arteries and DSA- or CTA-verified stenosis was present in 96 renal arteries. The kappa value for CEUS was 0.776 (P < 0.001), with an accuracy of 92.5%, a sensitivity of 94.7%, and a specificity of 84.0%. The accuracy of CEUS was the same for the diagnosis of the CKD3b-5 group as for the CKD1-3a group (100% vs. 87.5%, P = 0.148). There was no difference in CEUS accuracy for the diagnosis of Takayasu RAS compared with atherosclerotic RAS (95.8% vs. 91.7%, P = 0.795). Twenty-nine CEUS examinations were performed to follow in-stent restenosis or progression of RAS, with a median follow-up time of 5.0months (range 1.0-20.0). Two cases of in-stent restenosis in patients suffering from deteriorating kidney function and recurrent hypertension were examined by CEUS. CEUS examination is a credible alternative for diagnosing moderate and severe RAS in patients with CKD, and is a reliable tool for follow-up surveillance after renal artery revascularization treatment. It shouldn't be thought as a color-coded duplex ultrasonography rescue in these patients.

Numerical Analysis on A Non-Critical Stenosis in Renal Artery

The increase in cardiovascular diseases worldwide has resulted in higher death rate of people globally; the primary reason being atherosclerosis. A better understanding of this condition can be achieved through the application of numerical methods to understand the haemodynamics. The present study aims to investigate the effects of renal artery angulation on the flow characteristics in a non-critically stenosed artery compared to that of a normal artery in order to understand better, the reasons for causes and progression of renal artery stenosis. Abdominal aorta-renal artery models ranging from 30° to 90° angulations were generated from computerized tomography-angiogram slices, post which they were subjected to cleanup and defeaturing. Haemodynamic parameters such as velocity, pressure and time-averaged wall shear stress were evaluated at early systole, peak systole and peak diastole for the different artery models. Extensive amounts of flow recirculation were observed in normal renal arteries with higher bifurcating angles, whereas it was not the case in stenosed arteries where flow acceleration was seen for the duration of the cardiac cycle. Evaluation of static pressure encountered a similar trend where an increase in angulation saw a decrease in pressure for normal arteries which contradicted with stenosed artery results. Analysis of shear stress saw very similar trends in normal and stenosed arteries, with lower angulation profiles experiencing higher values of shear stress at the Ostia. In the cases of arteries of higher angulation with a non-critical stenosis, the possibility of worsening of stenosis into an opprobrious stage remains a concern.

BLOOD PRESSURE EFFECTS OVER TIME OF BIPOLAR RADIOFREQUENCY RENAL DENERVATION IN UNTREATED HYPERTENSION

Objective: It is believed that interruption of the renal nerves which lie in close proximity to the renal arteries, will effectively reduce blood pressure. As a first step, this study measured the blood pressure effects of ablating these nerves using radiofrequency energy produced by a bipolar catheter positioned into each renal artery in untreated hypertensive patients. Design and method: REINFORCE was a randomized, sham-controlled multicenter trial. Patients with office systolic blood pressure (SBP) of 150–180 mmHg and average 24-hour ambulatory SBP of 135–170 mmHg after medication washout underwent bipolar radiofrequency renal denervation or a sham procedure. The planned outcome was 8-week change in 24-hour ambulatory SBP. Enrollment was terminated for apparent futility before a sufficient sample for powered efficacy comparisons was enrolled, although patient observation continued. Safety assessments included all-cause death, renal failure, severe hypotension/syncope, hypertensive crisis, and renal artery stenosis. Results: Baseline 24-hour BP was 148.3 ± 10.9/85.7 ± 9.1 mmHg for the denervation group (N = 34, age 58.5 ± 10.1 years, 47% female) and 149.1 ± 7.2/86.4 ± 9.8 mmHg for the control group (N = 17, age 58.2 ± 9.8 years, 24% female). At 8 weeks, mean 24-hour SBP reductions for the renal denervation and control groups were 5.3 mmHg (95%CI -8.8, -1.8) and -8.5 mmHg (95%CI -13.3, -3.8), respectively (difference 3.3 [95%CI -2.8, 9.3]; p = .30). Antihypertensive medications could then be added. By 6 months, decreases in SBP were greater for the denervation group, yielding between-group differences of -7.2 (95%CI -15.2, 0.8; p = .08), -9.7 (95%CI -17.7, -1.7; p = .02), and -11.4 (95%CI -19.2, -3.7; p &lt; .01) for 24-hour, daytime ambulatory, and office measurements, respectively. Control rates (office SBP &lt; 140) were higher in the denervation group both at 6 months (52% vs. 12%, p &lt; 0.01) and 12 months (42% vs. 13%, p = 0.048). Medication use was similar in both groups. By 12 months, one denervation patient had a hypertensive urgency and one experienced progression of renal artery stenosis. Conclusions: The antihypertensive effects of renal denervation can be delayed for weeks following the procedure, but then appear to be sustained for at least 12 months.

The REDUCE HTN: REINFORCE: Randomized, Sham-Controlled Trial of Bipolar Radiofrequency Renal Denervation for the Treatment of Hypertension

ObjectivesThe aim of this study was to investigate bipolar radiofrequency renal denervation in patients with hypertension not receiving medications at baseline. BackgroundA blood pressure–reducing effect of renal denervation has been difficult to isolate in clinical investigations. MethodsREDUCE HTN: REINFORCE (Renal Denervation Using the Vessix Renal Denervation System for the Treatment of Hypertension) was a randomized, sham-controlled multicenter trial. Patients with office systolic blood pressure (SBP) of 150 to 180 mm Hg and average 24-h ambulatory SBP of 135 to 170 mm Hg after medication washout underwent bipolar radiofrequency renal denervation or a sham procedure. The planned outcome was 8-week change in 24-h ambulatory SBP. Enrollment was terminated for apparent futility before a sufficient sample for powered efficacy comparisons was enrolled. Safety assessments included all-cause death, renal failure, severe hypotension or syncope, hypertensive crisis, and renal artery stenosis. ResultsBaseline 24-h blood pressure was 148.3 ± 10.9/85.7 ± 9.1 mm Hg for the denervation group (n = 34, mean age 58.5 ± 10.1 years, 47% women) and 149.1 ± 7.2/86.4 ± 9.8 mm Hg for the control group (n = 17, mean age 58.2 ± 9.8 years, 24% women). At 8 weeks, mean 24-h SBP reductions for the renal denervation and control groups were −5.3 mm Hg (95% confidence interval [CI]: −8.8 to −1.8 mm Hg) and −8.5 mm Hg (95% CI: −13.3 to −3.8 mm Hg), respectively (difference 3.3 mm Hg; 95% CI: −2.8 to 9.3 mm Hg; p = 0.30). Antihypertensive medications could then be added. By 6 months, decreases in SBP were greater for the denervation group, yielding between-group differences of −7.2 mm Hg (95% CI: −15.2 to 0.8 mm Hg; p = 0.08), −9.7 mm Hg (95% CI: −17.7 to −1.7 mm Hg; p = 0.02), and −11.4 mm Hg (95% CI: −19.2 to −3.7 mm Hg; p < 0.01) for 24-h, daytime ambulatory, and office measurements, respectively. Through 12 months, 1 patient (renal denervation group) had a hypertensive urgency requiring immediate management, and 1 experienced progression of renal artery stenosis. ConclusionsFuture studies of radiofrequency renal denervation must anticipate delayed treatment effects. (Renal Denervation Using the Vessix Renal Denervation System for the Treatment of Hypertension [REDUCE HTN: REINFORCE]; NCT02392351)

Is isolated systolic hypertension an indication for renal denervation?

Ewen et al. recently reported in the journal Hypertension that they investigated, for the first time, the effect of renal denervation on blood pressure in 63 patients with isolated systolic hypertension (Ewen et al., 2014). The authors concluded that renal denervation reduced office and ambulatory blood pressure in patients with isolated systolic hypertension (Ewen et al., 2014). However, this conclusion may not be drawn, as renal denervation may not decrease ambulatory blood pressure in these patients. The potential risk of renal denervation may overweigh its benefit in patients with isolated systolic hypertension. Therefore, adjusted drug treatment may be recommended to these patients before renal denervation. Ambulatory blood pressure monitoring is the gold standard to diagnose true hypertension and removes the white coat effect (Hermida et al., 2013). Ambulatory blood pressure is superior to office blood pressure in predicting cardiovascular events (Staessen et al., 1999) and mortality (Dolan et al., 2005). The 24-h ambulatory systolic blood pressure in these 63 patients in Ewen et al.'s report decreased by 8 ± 8 and 7 ± 8 mm Hg at 6 and 12 months respectively after renal denervation. However, this study lacked a control group as the authors pointed out as a limitation. It has been reported that the sham procedure reduced 24-h ambulatory systolic blood pressure by 5 ± 15 mm Hg at 6 months (Bhatt et al., 2014). Therefore, compared with the sham procedure, renal denervation may not decrease ambulatory blood pressure in those patients with isolated systolic hypertension. Consequently, the risk posed to patients with isolated systolic hypertension by renal denervation may overweigh the minimal benefit of renal denervation via lowering blood pressure. For example, renal artery stenosis after renal denervation is of concern. The renal artery stenosis rate in the Symplicity HTN trials (N = 45, 106, and 535 for the Symplicity HTN-1, HTN-2, and HTN-3 trials, respectively) ranges from 0.3 to 2.2% (Krum et al., 2009; Esler et al., 2010; Bhatt et al., 2014). However, more and more studies with a smaller sample size (Worthley et al., 2013; Versaci et al., 2014) and case reports (Kaltenbach et al., 2012; Vonend et al., 2012; Aguila et al., 2014; Bacaksiz et al., 2014; Chandra et al., 2014; Pucci et al., 2014) showed relatively higher rates of development or progression of renal artery stenosis after renal denervation. Ewen et al. did not observe any hemodynamically significant renal artery stenosis in these 63 patients with isolated systolic hypertension within 12 months (Ewen et al., 2014). However, ultrasonography, which was used by the authors, has limitations in detecting renal artery stenosis (Zhang et al., 2009; Lao et al., 2011). Renal denervation is regarded as a last resort for patients with resistant hypertension (Persu et al., 2012). It is reported that about 9% of adults with hypertension suffer from resistant hypertension (Persell, 2011), which is often defined as elevated blood pressure despite treatment with at least 3 antihypertensive agents including a diuretic at maximal tolerated or highest recommended doses (Bohm et al., 2014). The prevalence of resistant hypertension is likely over-estimated due to drug non-adherence. For example, blood pressure in 20 of 65 patients with resistant hypertension was normalized after witnessed intake of antihypertensive drugs (Fadl Elmula et al., 2014). Resistant hypertension has been classified as “true” resistant hypertension if blood pressure is still elevated after witnessed intake of antihypertensive drugs (Fadl Elmula et al., 2014). Blood pressure in some patients with “true” resistant hypertension could be controlled by adjusted drug treatment. For example, Fadl Elmula et al. reported that adjusted drug treatment significantly decreased ambulatory systolic blood pressure from 152 ± 12 mm Hg at baseline to 133 ± 11 mm Hg at 6 months in 10 patients with “true” resistant hypertension (Fadl Elmula et al., 2014). In addition, adjusted drug treatment lowered ambulatory systolic blood pressure to below 135 mm Hg in 7 of these 10 patients with “true” resistant hypertension (Fadl Elmula et al., 2014). Therefore, patients with isolated systolic hypertension may be offered with adjusted drug treatment before being offered with renal denervation. In summary, renal denervation may not decrease ambulatory blood pressure in patients with isolated systolic hypertension. Adjusted drug treatment may be recommended to these patients before renal denervation, as the risk might overweigh the benefit of renal denervation in these patients.

Progression of Renal Artery Stenosis After Renal Denervation

Progression of Renal Artery Stenosis After Renal Denervation

Co-Existence of Carotid Artery Disease, Renal Artery Stenosis, and Lower Extremity Peripheral Arterial Disease in Patients With Coronary Artery Disease

In atherosclerosis, carotid artery stenosis (CAS), renal artery stenosis (RAS), lower extremity peripheral arterial disease (PAD), and coronary artery disease (CAD) are common pathologic lesions; their interrelationship is, however, unclear. We studied concomitant multiple atherosclerotic lesions in patients with CAD to understand their prevalence and relations. A cross-sectional analysis was performed on data from consecutive patients who underwent nonemergent coronary angiography. Simultaneous carotid and renal artery Doppler studies and ankle-brachial systolic pressure measurements were reviewed to diagnose concomitant lesions and their severity. The study included 1,734 patients (aged 71 ± 9 years; 70% men), with prevalences of CAS, RAS, lower extremity PAD, and CAD of 6%, 7%, 13%, and 72%, respectively. In patients with CAD (n = 1,253), the prevalences of CAS, RAS, and lower extremity PAD were 7%, 9%, and 16%, respectively; 24% CAD patients had ≥1 additional atherosclerotic lesion. Significant interactions among the prevalences of these lesions were found. In addition, the extent of CAD and the prevalences of CAS, RAS, and lower extremity PAD were significantly correlated. Multivariate analysis supported these relationships. In conclusion, the prevalences of CAS, RAS, lower extremity PAD, and CAD were strongly interrelated in the study population; CAD severity was related to that of other atherosclerotic lesions. Additional systematic screening of other concomitant atherosclerotic lesions is recommended, especially in CAD patients having multivessel disease, left main disease, and/or already diagnosed with other concomitant atherosclerotic lesions.

Atherosclerotic Peripheral Vascular Disease Symposium II

The primary goal of this American Heart Association renal intervention writing group was to discuss current controversies related to renal interventions and to recommend important areas of clinical research and advocacy initiatives in this peripheral arterial bed. The 4 areas covered in this section include (1) management of asymptomatic renal artery disease, (2) treatment of ischemic nephropathy, (3) prevention and treatment of atheroembolism in renal artery interventions, and (4) treatment of renal in-stent restenosis (ISR). Atherosclerotic renal artery disease is an often unrecognized contributor to refractory hypertension, renal insufficiency, and increased risk of cardiovascular death.1,2 Renal artery disease is associated with increased cardiovascular events (myocardial infarction, stroke, and death), and when associated with symptomatic coronary artery disease, it independently doubles the risk of death.3 Additionally, the presence of bilateral renal artery stenoses is associated with a reduced 4-year survival rate when compared with unilateral disease (47% versus 59%, P <0.001).3 Hypertension, renal insufficiency, and multisystem atherosclerosis are common entities, and the independent occurrence of these conditions is frequent. Thus, the physician must distinguish between association and causation in the evaluation of patients with atherosclerotic renal artery disease and critically appraise the potential for clinical improvement in selecting patients for renal artery intervention. In contrast to other regional manifestations of atherosclerosis, it is impractical to classify patients with atherosclerotic renal artery disease into symptomatic or asymptomatic categories. Two of the cardinal manifestations of renal artery disease, hypertension and renal insufficiency, are frequently “silent” with regard to clinical manifestations until end-organ damage or uremia occurs. Thus, the majority of patients may be deemed asymptomatic. A more appropriate classification of patients with atherosclerotic renal artery disease may be to classify them in relation to potential clinical consequences. We propose the following classification scheme in patients with renal artery disease:

Diagnosis and Management of Ischemic Nephropathy

Analysis of the Third National Health and Nutrition Examination Survey (1988 to 1994) suggests that chronic kidney disease (CKD) is a major public health problem (1). Approximately 11% of the US population has CKD. Roughly half have a GFR <60 ml/min per 1.73 m2 with or without kidney damage (stages 3 to 4), and half have exclusively kidney damage as manifested by microalbuminuria (stages 1 to 2) (2). It is widely recognized that the prevalence of stage 5 CKD is also increasing at a rapid rate, and it is estimated that the number of patients who have ESRD may reach 2.24 million by 2030 (3). Evidence to establish reduced GFR as an independent risk factor for cardiovascular disease (CVD) mortality has emerged. Analysis of data from several population-based epidemiologic studies (4,5) demonstrates poorer outcomes regarding stroke, myocardial infarction, and congestive heart failure (CHF) in patients with even mild compromise of kidney function. The morbidity of this group of patients constitutes an economic burden both directly in terms of resource utilization and indirectly through loss of productivity and impaired quality of life (2). Atherosclerotic renovascular disease (ARVD) can result in renovascular hypertension. However, ARVD is an increasingly recognized cause of CKD (6,7). In this article, we focus mainly on ARVD or renal artery stenosis (RAS) secondary to atherosclerosis as a cause of ischemic nephropathy. ARVD is a disease of aging, and several studies have shown its strong association with extrarenal atherosclerotic disease (8–10). Patients with ARVD seem to be at a much greater risk for cardiovascular death than for progressing to renal replacement therapy (11). Whether renal revascularization can benefit renal and cardiovascular outcomes has not been established. Atherosclerosis is the cause of approximately 90% of RAS in adults who are older …

Fluid Dynamics in Normal and Stenosed Human Renal Arteries: an Experimental and Computational Study

Atherosclerotic renal artery stenosis (RAS), which accounts for approximately 7% of peripheral vascular diseases, is considered a major cause for secondary hypertension and other renal complications such as chronic renal failure and ischemic nephropathy. In this study, the fluid dynamic features of a human aortorenal bifurcation are investigated in detail with a computational fluid dynamics (CFD) solver to assess the localization of RAS in relation to the sites exposed to abnormal hemodynamic events. Specially, a normal renal artery is artificially rendered stenosed to examine the RAS-induced hemodynamic changes and their effect on the progression of RAS. The CFD solver is partially validated by a model experiment conducted for steady state flow. The computed results indicate that low oscillatory wall shear stress (WSS), which stands for the most prominent hemodynamic factor responsible for atherosclerosis, correlates intimately with flow separation; WSS distribution depends significantly on vascular geometric structure; and RAS may elicit pronounced flow disturbances that are likely to promote the spread of atherosclerotic lesions towards downstream region.

Endovascular aneurysm repair with suprarenal vs infrarenal fixation: A study of renal effects

Although suprarenal fixation may be of benefit during endovascular aneurysm repair (EVAR), its safety with regards to renal effects remains uncertain. To date, there has been no controlled study of the topic, with most reports relying upon single-center experiences that use heterogeneous patient populations and devices from different manufacturers. The purpose of this analysis was to evaluate the effect of suprarenal fixation on renal function by comparing homogeneous patient populations receiving EVAR grafts from a single manufacturer that are identical in design and delivery method, except for utilizing either suprarenal (SR) or infrarenal (IR) fixation. During two pivotal US Food and Drug Administration trials, 283 patients underwent EVAR with the Powerlink bifurcated graft. The trials' inclusion and exclusion criteria and grafts were identical except for fixation scheme. Clinical, laboratory, and computed tomographic (CT) data were retrospectively reviewed. A comparison of preoperative, perioperative (1 to 7 days), and postoperative (>7 days) alterations in serum creatinine (SCr), creatinine clearance (CrCl), and blood pressure was performed. Renal adverse events were determined by CT scan and clinical chart review and included renal infarction, renal artery stenosis (either progressive or requiring renal stent placement), and renal artery occlusion. Both SR and IR groups demonstrated a significant increase in SCr and a decrease in CrCl over time. No significant difference in SCr or CrCl existed between groups during any time period. There were no differences in postoperative renal impairment (IR, 10.2%; SR, 7.6%, P = .634), the need for hemodialysis (IR, 0.7%; SR, 0%, P = 1.00), or systolic and diastolic blood pressure during subsequent follow-up between treatment groups. There was no significant difference in the number of renal adverse events detected by CT between the IR (10, 6.8%) and SR (3, 3.8%) groups (P = .550). Suprarenal fixation does not lead to a significant increase in acute renal events, renal impairment, or alteration in blood pressure compared with infrarenal fixation. Patients undergoing aneurysm repair with devices that use either suprarenal or infrarenal fixation develop progressive renal dysfunction over time. Further studies are needed to determine the long-term effects of suprarenal fixation on renal function and progression of renal artery stenosis.

What is critical renal artery stenosis?: Implications for treatment

Renovascular disease due to progressive atherosclerotic renal artery stenosis is being diagnosed with increasing frequency in the elderly. At what degree of renal artery stenosis should intervention be recommended is not clear. To answer this question, unilateral or bilateral activation of the renin-angiotensin system or its absence were detected by captopril-stimulated renal vein renin measurements in 49 hypertensive patients, aged 63 years, with normal or near-normal renal function (serum creatinine concentration ≤2.0 mg/dL), and the information was matched against radiographic measurements of the extent of renal artery stenosis. With few exceptions, unilateral or bilateral hypersecretion of renin was associated with 80% or greater reduction of renal artery lumen diameter. In contrast, normal secretion or suppression of renin production in a kidney contralateral to an ischemic one was associated with either normal caliber renal artery or renal artery stenosis less than 80%. These findings suggest that renal artery stenosis less than 80% should be monitored rather than treated because improvement of renal function and amelioration of hypertension are not expected unless the renin-angiotensin system has been activated in the affected kidney. Renoprotection by early intervention is uncertain because progression of renal artery stenosis is unpredictable. Normal captopril-stimulated renal vein renin measurements in hypertensive patients obviate the need for further work-up or interventional therapy of renovascular disease.

Progression of renal artery stenosis in patients undergoing cardiac catheterization

Background Renal artery stenosis is potentially correctable by either revascularization surgery or percutaneous methods. However, appropriate use of these techniques has been hampered by a lack of data on the natural history of this disease. This study assesses the prevalence, risk factors for progression, and effect on renal function of angiographically demonstrated renal artery disease in patients undergoing cardiac catheterization. Methods The severity of renal artery stenosis was quantified in all patients who underwent abdominal aortography as part of a diagnostic cardiac catheterization study at Duke University Medical Center between January 1989 and February 1996. Results There were 14,152 patients in the study (mean age 61 ± 12 years, 62% male). Normal renal arteries were identified in 12,543 (88.7%) patients, insignificant disease (<50% stenosis) in 1 or more vessels in 726 patients (5.1%), and significant stenosis in 883 patients (6.3%). Significant bilateral renal artery stenosis was present in 178 patients (1.3%). By multivariate logistic regression, elevated serum creatinine level, coronary artery disease, peripheral vascular disease, hypertension, cerebrovascular disease, older age, female sex, and family history of coronary artery disease were identified as independent predictors of significant renal arterial disease. Disease progression was assessed in 1189 patients. Mean time between cardiac catheterizations was 2.6 ± 1.6 years. Significant disease progression occurred in 133 patients (11.1%). Independent predictors of disease progression were female sex, age, coronary artery disease at baseline, and time between baseline and follow-up. At follow-up, serum creatinine level was significantly higher in patients who demonstrated ≥75% stenosis in 1 or more vessels (mean creatinine level 141 ± 114 μmol/L compared with those with insignificant disease (mean creatinine level 97 ± 44 μmol/L ( P = .01). Conclusions Renal artery disease is frequently progressive in patients who undergo cardiac catheterization for investigation of coronary artery disease. Significant stenotic disease may develop over a short period despite evidence of normal renal arteries at prior catheterization. (Am Heart J 1998;136:913-8.)

Impact of transrenal aortic endograft placement on endovascular graft repair of abdominal aortic aneurysms

Purpose: Successful endovascular repair of an abdominal aortic aneurysm (AAA) requires the creation of a hemostatic seal between the endograft and the underlying aortic wall. A short infrarenal aortic neck may be responsible for incomplete aneurysm exclusion and procedural failure. Sixteen patients who had an endograft positioned completely below the lowest renal artery and 37 patients in whom a porous portion of an endograft attachment system was deliberately placed across the renal arteries were studied to identify if endograft positioning could impact on the occurrence of incomplete aneurysm exclusion. Methods: Fifty-three patients underwent aortic grafting constructed from a Palmaz balloon expandable stent and an expandable polytetrafluoroethylene (ePTFE) graft implanted in an aorto-ilio-femoral, femoral-femoral configuration. Arteriography, duplex ultrasonography and spiral CT scans were performed in each patient before and after endografting to evaluate for technical success, the presence of endoleaks, and renal artery perfusion. Results: There was no statistically significant difference in patient demography, AAA size, or aortic neck length or diameter between patients who had their endografts placed below or across the renal arteries. However, significantly more proximal aortic endoleaks occurred in those patients with infrarenal endografts ( P ≤.05). Median serum creatinine level before and after endografting was not significantly different between the 2 patient subgroups, with the exception of 2 patients who had inadvertent coverage of a single renal orifice by the endograft. Median blood pressure and the requirement for antihypertensive therapy remained the same after transrenal aortic stent grafting. Significant renal artery compromise did not occur after appropriately positioned transrenal stents as shown by means of angiography, CT scanning, and duplex ultrasound scan. Mean follow-up time was 10.3 months (range, 3 to 18 months). Patients who had significant renal artery stenosis (≥50%) before aortic endografting did not show progression of renal artery stenosis after trans-renal endografting. Two patients with transrenal aortic stent grafts had inadvertent coverage of 1 renal artery by the endograft because of device malpositioning, which resulted in nondialysis dependent renal insufficiency. In addition, evidence of segmental renal artery infarction (<20% of the kidney), which did not result in an apparent change in renal function, was shown by means of follow-up CT scans in 2 patients with transrenal endografts. Conclusion: Transrenal aortic endograft fixation using a balloon expandable device in patients with AAAs can result in a significant reduction in the risk of proximal endoleaks. Absolute attention to precise device positioning, coupled with the use of detailed imaging techniques, should reduce the risk of inadvertent renal artery occlusion from malpositioning. Long-term follow-up is essential to determine if there will be late sequelae of transrenal fixation of endografts, which could adversely effect renal perfusion. (J Vasc Surg 1998;28:638-46.)