Prevalence and predictors of renal artery stenosis in patients with myocardial infarction

Admission proteinuria predicts the incidence of acute kidney injury among patients with acute ST-segment elevation myocardial infarction: a retrospective cohort study

BACKGROUND

Proteinuria indicates renal dysfunction and is associated with the development of acute kidney injury (AKI) in several conditions, but the association between proteinuria and AKI in patients with ST-segment elevation myocardial infarction (STEMI) remains unclear. This research aims to investigate the predictive value of proteinuria for the development of AKI in STEMI patients.

METHODS

A total of 2735 STEMI patients were enrolled. The present study's endpoint was AKI incidence during hospitalization. AKI is defined according to the Kidney Disease: Improving Global Outcomes criteria. We defined proteinuria, measured with a dipstick, as mild (1+) or heavy (2+ to 4+). Multivariate logistic regression and subgroup analyses were used to testify to the association between proteinuria and AKI.

RESULTS

Overall, proteinuria was observed in 634 (23.2%) patients. Multivariate logistic regression analyses revealed that proteinuria [odds ratio (OR), 1.58; 95% confidence interval (CI), 1.25-2.00; P  < 0.001] was the independent predictive factor for AKI. Severe proteinuria was associated with a higher adjusted risk for AKI compared with the nonproteinuria group (mild proteinuria: OR, 1.35; 95% CI, 1.04-1.75; P  = 0.025; severe proteinuria: OR, 2.50; 95% CI, 1.70-3.68; P  < 0.001). The association was highly consistent across all studied subgroups. (all P for interaction >0.05).

CONCLUSION

Admission proteinuria measured using a urine dipstick is an independent risk factor for the development of AKI in STEMI patients.

Unenhanced respiratory-gated magnetic resonance angiography (MRA) of renal artery in hypertensive patients using true fast imaging with steady-state precession technique compared with contrast-enhanced MRA

OBJECTIVE

This study was aimed to evaluate the accuracy of "True Fast Imaging with Steady-State Precession" (TrueFISP) MR angiography (MRA) for diagnosis of renal arterial stenosis (RAS) in hypertensive patients.

METHODS

Twenty-two patients underwent both TrueFISP MRA and contrast-enhanced MRA (CE-MRA) on a 1.5-T MR imager. Volume of main renal arteries, length of maximal visible renal arteries, number of visualized branches, stenotic grade, and subjective quality were compared. Paired 2-tailed Student t test and Wilcoxon signed rank test were applied to evaluate the significance of these variables.

RESULTS

Volume of main renal arteries, length of maximal visible renal arteries, and number of branches indicated no significant difference between the 2 techniques (P > 0.05). Stenotic degree of 10 RAS was greater on CE-MRA than on TrueFISP MRA. Qualitative scores from TrueFISP MRA were higher than those from CE-MRA (P < 0.05).

CONCLUSIONS

TrueFISP MRA is a reliable and accurate method for evaluating RAS.

Renal artery stenosis - an update

Renal artery stenosis (RAS) is a common form of peripheral arterial disease. The most common cause of RAS is atherosclerosis. It is predominantly unilateral. The pathophysiologic mechanism stems from renal underperfusion resulting in the activation of the renin- angiotensin-aldosterone pathway. Even though the majority of patients with RAS are asymptomatic, it can clinically present with hypertension, nephropathy and congestive heart failure. This progressive disease can lead to resistant hypertension and end stage kidney failure. Screening patients for RAS with either Doppler ultrasonography, computed tomographic angiography, or magnetic resonance angiography is preferred. Adequate blood pressure control, goal-directed lipid-lowering therapy, smoking cessation, and other preventive measures form the foundation of management of patients with RAS. Catheter-based percutaneous revascularization with angioplasty and stenting showed modest clinical benefit for patients in small retrospective studies, but data from randomized clinical trials failed to confirm these beneficial results. The current ongoing Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial may provide more concrete data regarding the role of stenting in RAS. Surgical revascularization is considered only if catheter-based revascularization is unsuitable or unsuccessful. The American College of Cardiology/American Heart Association guidelines on evaluation and management of patients with RAS provide the framework for determining individualized assessment and treatment plans for patients with RAS.

A decline in glomerular filtration rate rather than renal arterial stenotic lesions, per se, predicts cardiovascular-renal events in type 2 diabetic patients

BACKGROUND

In diabetic patients with renal artery arteriosclerosis (RAAS), the factors associated with a greater risk for cardiovascular-renal events (CVREs) remain unclear: the decline in estimated glomerular filtration rate (eGFR) caused by RAAS or the advance of arteriosclerosis that causes RAAS. Hence, the features to determine which best predicts the onset of CVREs in such patients were compared.

METHODS AND RESULTS

The renal arteries of 162 type 2 diabetes patients were assessed by using magnetic resonance angiography (RAAS diagnosed as arteriosclerotic stenosis ≥50%) and they were studied longitudinally over 7 years. The influence of the presence/absence of RAAS, a decline in eGFR, clinical factors, surrogate arteriosclerotic markers and ischemic markers on patient's CVREs were assessed. A Cox regression analysis showed the detection of RAAS to be an independent risk factor for CVREs (bilateral RAAS was an extremely strong risk factor for the development of CVREs within 1,000 days), as was the decline in eGFR in a logistic regression analysis; the latter being a more powerful risk factor for CVREs. A multiple regression analysis revealed angiopoietin-2, a marker of ischemia, to be a risk factor for the decline in eGFR.

CONCLUSIONS

A decline in renal function but not the renal arterial stenotic lesion itself appears to be associated with an increased incidence of CVREs in type 2 diabetic patients with RAAS.

Prevalence and predictors of renal artery stenosis in patients undergoing peripheral and coronary angiography

BACKGROUND

Renal artery stenosis is a potential cause of secondary hypertension, ischemic nephropathy and end-stage renal disease. Atherosclerosis is by far the most common etiology of renal artery stenosis in elderly. We investigated whether the presence of significant atherosclerotic renal artery stenosis (ARAS) with luminal diameter narrowing ≥50 % could be predicted in patients undergoing peripheral and coronary angiography.

METHODS

The records of 3,500 consecutive patients undergoing simultaneous renal angiography along with peripheral and coronary angiography were reviewed. The patients with known renal artery disease were excluded.

RESULTS

Prevalence of ARAS was 5.7 %. Significant ARAS (luminal diameter narrowing ≥50 %) was present in 139 patients (3.9 %). Hypertension with altered serum creatinine and triple-vessel CAD were associated with significant renal artery stenosis in multivariate analysis. No significant relationship between the involved coronary arteries like left anterior descending, left circumflex, right coronary artery and ARAS was found. Only hypertension and altered serum creatinine were associated with bilateral ARAS. Extent of CAD or risk factors like diabetes, hyperlipidemia or smoking did not predict the unilateral or bilateral ARAS.

CONCLUSION

Prevalence of ARAS among the patients in routine cardiac catheterization was 5.7 %. Hypertension is closely associated with significant ARAS. Significant CAD in the form of triple-vessel disease and altered renal function tests are closely associated with ARAS. They predict the presence of significant renal artery stenosis in patients undergoing routine peripheral and coronary angiography. Moreover, hypertension and altered renal functions predict bilateral ARAS.

Kidney function and histological damage in autopsy subjects with myocardial infarction

OBJECTIVES

Chronic kidney disease (CKD) is a major risk factor for cardiovascular disease (CVD). We previously reported renal parenchymal damage in autopsy subjects with stroke or abdominal aortic aneurysm. The aim of this study is to evaluate the relationship between renal histology and clinical characteristics of patients with myocardial infarction (MI).

METHODS

A total of 699 subjects were autopsied at the National Cerebral and Cardiovascular Center Hospital. We retrospectively evaluated all autopsy cases with MI (n = 123). Estimated glomerular filtration rate (eGFR) was calculated using the Japanese formula. Subjects were classified into four groups: 25 subjects with eGFR ≥ 60 mL/min/1.73 m(2) and no proteinuria (no CKD), 10 subjects with eGFR ≥ 60 and proteinuria (CKD1/2), 65 subjects with 60 > eGFR ≥ 30 (CKD3), and 23 subjects with eGFR < 30 (CKD4/5). Renal parenchymal damage was evaluated using a semi-quantitative histological score (score 0-3) for glomerulosclerosis, interstitial fibrosis, tubular atrophy, arteriolar hyalinosis, and arteriosclerosis of medium-sized artery (maximum score = 15).

RESULTS

The mean histological score was significantly higher in patients with CKD3 and CKD4/5 and was associated with age, hypertension, diabetes, kidney function, proteinuria, and other CVD.

CONCLUSIONS

In patients with MI, renal parenchymal damage and deteriorating kidney function are closely associated.

Prevalence of renal artery stenosis in flash pulmonary oedema: determination using gadolinium-enhanced MRA

PURPOSE

The primary purpose was to determine the prevalence of renal artery stenosis (RAS) in patients presenting with acute ("flash") pulmonary oedema (FPE), without identifiable cause using contrast-enhanced magnetic resonance angiography (CE-MRA) of renal arteries. A secondary goal was to correlate clinical parameters at presentation with the presence or absence of RAS.

MATERIALS AND METHODS

Patients presenting with acute pulmonary oedema without identifiable cause prospectively underwent CE-MRA. >50% renal artery stenosis was considered significant. Clinical parameters (blood pressure, serum creatinine, history of hypertension/hyperlipidaemia) were compared in patients with and without RAS using an unpaired t-test. Results expressed; mean (+/-SD).

RESULTS

20 patients (4 male, 16 female, age 78.5+/-11 years) underwent CE-MRA. 9 patients (45%) had significant RAS (6 (30%) bilateral, 3 (15%) unilateral). Systolic BP was higher in patients with RAS (192+/-38 mm Hg) than those without (134+/-30 mm Hg) (p<.005). Diastolic BP was higher in patients with RAS (102+/-23 mm Hg) than those without (76+/-17 mm Hg) (p<.01). All patients with RAS and 6/11(55%) patients without RAS had a history of hypertension. No significant difference in creatinine or hyperlipidaemia history was observed.

CONCLUSION

The prevalence of RAS in patients presenting with FPE is 45%. The diagnosis should be considered in patients presenting with unexplained acute pulmonary oedema, particularly if hypertensive at presentation.

Magnetic resonance angiography and Doppler scanning for detecting atherosclerotic renal artery stenosis

BACKGROUND

Atherosclerotic renal artery stenosis (ARAS) is a progressive but potentially reversible chronic kidney disease. Although the high sensitivity and specificity of renal Doppler scanning (RDS) for ARAS has been reported in western countries, ARAS has not been detected by RDS. This study used magnetic resonance angiography (MRA) to evaluate the sensitivity and specificity of RDS for detecting ARAS among outpatients at a nephrology clinic, and to calculate the degree of underestimation of ARAS by RDS.

METHODS

A total of 257 outpatients, aged > 50 years were examined for ARAS by RDS and MRA.

RESULTS

Thirty-seven (14.4%) and 139 (54.1%) of 257 patients had stenosis detected by RDS and MRA, respectively. Among the 220 patients whose RDS results were negative, MRA detected stenosis in 111 (50.45%). Multivariate logistic regression analysis showed that age > 65 years, duration of smoking, coronary artery disease, and serum creatinine levels > 354 mmol/L (4 mg/dL) were significant and independent factors that influenced ARAS in patients with negative results by RDS.

CONCLUSION

RDS might still be the diagnostic procedure of choice for screening outpatients for ARAS because it is inexpensive, convenient, able to detect severity, and avoids the use of contrast media. When RDS is negative in aged people who have smoked longer than 20 years, with coronary artery disease or serum creatinine > 4 mg/dL, MRA is recommended for further evaluation of ARAS.

Cardiovascular morbidity and mortality and renal artery stenosis

Renal artery stenosis (RAS) is a common manifestation of atherosclerosis and is associated with many other atherosclerotic conditions. Cardiovascular morbidity and mortality is increased among patients with RAS. This increase is likely due in part to the associated disease states; however, RAS itself may also contribute. Current strategies to limit cardiovascular morbidity and mortality in RAS include various pharmacologic interventions targeting both RAS atherosclerosis in general. Additionally, revascularization has been advocated; however, clear data are lacking. Ongoing clinical trials such as the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial will ultimately help to determine the best strategies to limit the morbidity and mortality associated with RAS.

Epidemiology and natural history of atherosclerotic renovascular disease

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

Clinical practice. Renal-artery stenosis

A 73-year-old former smoker with a history of hypertension and dyslipidemia presents to the emergency department with shortness of breath. His blood pressure is 160/75 mm Hg, heart rate 60 beats per minute, and respiratory rate 24 breaths per minute. Chest auscultation reveals diffuse rales, and there is 1+ pitting edema. The serum creatinine level is 1.4 mg per deciliter (124 µmol per liter) (estimated glomerular filtration rate, 52 ml per minute), and urinalysis shows 1+ protein. His condition improves after treatment with intravenous diuretics, but his systolic blood pressure remains elevated, at 170 mm Hg. Magnetic resonance angiography (MRA) reveals a diseased aorta, a high-grade ostial lesion of the left renal artery that is consistent with atherosclerotic stenosis, and a normal right renal artery. How should he be further evaluated and treated?

The prevalence of atherosclerotic renal artery stenosis in risk groups: a systematic literature review

OBJECTIVE

We performed a literature review and analysis to improve the insight in the prevalence of renal artery stenosis (RAS) in risk groups.

METHODS

Relevant studies were identified by a MEDLINE and EMBASE database search (1966 to December 2007), complemented by hand searching of reference lists. Review was restricted to English language studies, using any form of angiography as diagnostic method. Studies were grouped in risk group categories sharing similar clinical characteristics, and pooled prevalence rates were calculated for each category.

RESULTS

Forty studies, involving a total number of 15 879 patients, were identified. The following pooled prevalence rates (95% confidence interval; sample size risk group) of RAS were found: suspected renovascular hypertension, 14.1% (12.7-15.8%; n = 1931); hypertension and diabetes mellitus, 20% (14.9-25.1%; n = 240); coronary angiography (CAG) in consecutive patients, 10.5% (9.8-11.2%; n = 8011); CAG in hypertensive patients, 17.8% (15.4-20.6%; n = 836); CAG and suspected renovascular disease, 16.6% (14.8-18.5%; n = 1576); congestive heart failure, 54.1% (45.7-62.3%; n = 135); peripheral vascular disease, 25.3% (23.6-27.0%; n = 2632); abdominal aortic aneurysm, 33.1% (27.4-39.2%; n = 239) and end-stage renal failure, 40.8% (27-55.8%; n = 49.) In patients with an incidentally discovered RAS, hypertension and renal failure were present in 65.5 and 27.5%, respectively.

CONCLUSION

RAS has a high prevalence in risk groups, especially in those with extrarenal atherosclerosis, end-stage renal failure and heart failure. These findings are important when screening for RAS or prescription of an angiotensin converting enzyme inhibitor or angiotensin-II receptor blocker is considered.

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

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

Combined heart-kidney transplantation: a review of recipient selection and patient outcomes

Elevated serum creatinine is a common finding among patients awaiting heart transplantation because of reduced renal perfusion in the setting of severe heart failure as well as overlapping risk factors for chronic kidney disease and heart disease. Patients with significant renal dysfunction preoperatively have worse outcomes with heart transplantation alone compared with those with normal renal function or those with renal dysfunction who undergo combined heart-kidney transplantation. Optimizing organ distribution and patient outcomes after cardiac transplantation requires appropriate recipient selection, including deciding which patients will benefit from combined heart-kidney transplantation. This review focuses on the evaluation of patients with chronic kidney disease awaiting heart transplantation and the outcomes of combined heart-kidney transplantation.

[Atherosclerotic renal artery disease management update]

In the case of atherosclerotic renal artery disease, the best conclusive results lie principally not in the degree of the stenosis but rather in the degree the renal parenchymal disease beyond the stenosis itself. These determining factors involve the controlling of the patients blood pressure, the improvement in the renal function and the beneficial results to the cardiovascular system. Besides the indispensable medical treatment, a revascularisation by angioplasty may be indicated. This procedure with or without vascular stent often allows satisfactory angiographic results. A treatment by surgical revascularisation is only recommended in the case of extensive atherosclerotic lesions of the aorta, complex lesions of the latter or an abdominal aortic aneurism. Although the frequency of restenosis of angioplasty with stent remains extremely low, the risk of cholesterol emboli due to the diffuse atherosclerotic lesions of the abdominal aorta, must be considered at the time of each aortic catheterization. The therapeutic approach of atherosclerotic renal artery disease must be dictated by the whole cardiovascular risk factors and by the threat of target organs. The control of the blood pressure and the maintenance of the renal function must be integrated in the decisional algorithm as well as the possible risks in carrying out an eventual revascularisation procedure. Finally, the renal angioplasty should in numerous situations be integrated in the overall assumption of responsibility of the atherosclerotic vascular diseases, and should be part of the medical treatment. Several questions still do exist; at what moment an atherosclerotic renal artery stenosis should and e considered critical, and which procedure should be considered for which patient? The purpose of this review is to propose a decisional tool for individualized treatments in the light of results from randomized and controlled studies.

Catheter-based therapy for atherosclerotic renal artery stenosis

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

[Prevalence of renal artery stenosis in patients with critical limb ischemia]

BACKGROUND AND OBJECTIVE

Our purpose was to evaluate the prevalence of renal artery stenosis in patients with critical limb ischemia and to study any clinical or laboratory indicator that could predict this association.

PATIENTS AND METHOD

One hundred consecutive patients with critical limb ischemia evaluated by angiogram were included in the study from January to July 2003. Cardiovascular risk factors and renal function were analyzed.

RESULTS

One hundred angiographic studies have been analyzed. Thirty nine (39%) of our patients had some type of pathology of the renal artery but the rest, 61 (61%), had normal and healthy renal arteries. In 5 patients, a bilateral renal pathology was found. Severe disease (> 60% stenosis, bilateral or renal occlusion) was present in 15 cases including 6 occlusions. Once we compared the patients with healthy renal arteries with the patients with different degrees of stenosis, we did not appreciate significant differences in hypertension, diabetes, coronary disease or smoking habit, nor with laboratory data such as creatinine, urea, c-reactive protein, total cholesterol or atherogenic index. No differences were found either comparing patients with normal renal artery with patients with bilateral pathology or with unilateral occlusion.

CONCLUSIONS

There is a high prevalence of renal artery pathology in patients with critical limb ischemia although we have not found any clinical or laboratory factors useful to identify them.

Atherosclerotic renovascular disease and renal impairment: can we predict the effect of intervention?

Atherosclerotic renal artery stenosis (ARAS) is associated with hypertension, ischemic nephropathy, and high cardiovascular risk. We review the data on revascularization of the renal artery by percutaneous transluminal renal angioplasty (PTRA) and pharmacological therapy. In patients with severe ARAS and poorly controlled hypertension, PTRA can improve blood pressure control. In patients with rapid renal function loss and severe ARAS, PTRA can improve short-term renal function, but there is no evidence for long-term renoprotection. Recent evidence indicates that ARAS, and incidental renal artery stenosis, considerably increases cardiovascular risk, independent of blood pressure, renal function, and prevalent risk factors. This suggests that revascularization might potentially improve overall prognosis, but no data are available currently. The high cardiovascular risk warrants aggressive pharmacological treatment to prevent progression of the generalized vascular disorder. Ongoing trials will show whether revascularization has added, long-term effects on blood pressure, renal function, and cardiovascular prognosis.

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

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

Ischemic nephropathy

Ischemic nephropathy is an independent pathway towards end-stage renal disease. Its prevalence is estimated to be significant and increasing among populations with vascular disease, hypertension, and chronic renal failure. Angiography remains the gold standard for evaluation of ischemic nephropathy; however, selection by clinical criteria and noninvasive screening with ultrasound are recommended for most patients. Surgical revascularization of ischemic kidneys can halt or reverse deterioration of renal function and is preferable to medical treatment. Direct comparison of angioplasty and stent placement with surgery is needed.

Prevalence and Risk Factors of Atherosclerotic Renal Artery Stenosis in 1,200 Chinese Patients Undergoing Coronary Angiography

AIMS

Atherosclerotic renal artery stenosis (ARAS) is a common and potentially reversible cause of end-stage renal failure. Our study aimed to determine the prevalence and predictors of ARAS in Chinese patients undergoing coronary angiography for suspected coronary heart disease (CAD), or for acute or chronic myocardial infarction.

METHODS

Selective renal arteriography was performed immediately after coronary angiography in 1,200 consecutive patients. Medical history and laboratory data were obtained before the procedure. Significant renal artery stenosis was defined as > or =50% narrowing of the luminal diameter. Uni- and multivariate logistic regression analyses were made to explore the association of the clinical and laboratory variables, including some items which had never or rarely been studied, with ARAS or CAD.

RESULTS

Of the 1,200 patients, 840 were male and 360 female. Their mean age was 62 +/- 10 years. Low-grade (<50%) and significant coronary artery stenosis was found in 108 (9%) and 610 (51%) patients respectively. By multivariate logistic regression analysis, risk factors associated with the presence of coronary artery stenosis included male, older age, smoking, high serum concentration of low density lipoprotein, lipoprotein (a), and fast blood glucose > or =7.0 mmol/l. Significant ARAS was present in 116 (9.7%) patients, of which 20 (1.7%) were bilateral. The incidence of ARAS was similar in patients with suspected CAD or myocardial infarction. Multivariate logistic regression analysis showed the association of the clinical variables with ARAS included: older age, hypercholesterolemia, a more than 10-year history of hypertension, proteinuria and S(Cr) > or =133 micromol/l. The severity of ARAS is significantly related to the severity of coronary artery disease.

CONCLUSION

ARAS is a frequent finding in Chinese patients undergoing coronary angiography, especially in patients with significant coronary artery stenosis and risk factors for ARAS. Renal arteriography can be a helpful examination in these patients.

Renal Function in Patients with Abdominal Aortic Aneurysm

AIMS

Renal dysfunction occurs occasionally after the repair of abdominal aortic aneurysm (AAA), and preoperative renal function is considered as one of the potential causes. The present study was designed to evaluate and compare renal function and risk factors of AAA patients with those of hypertensive patients.

METHODS

We prospectively examined 95 patients with AAA and 72 patients with essential hypertension (HT) without other cardiovascular diseases (CVD). Renal function, urinary albumin excretion (UAE) and renal scintigraphy were compared. Kidney size was calculated using ultrasonography.

RESULTS

Serum creatinine and creatinine clearance in AAA patients was worse than in HT patients. Smoking status was more apparent in AAA patients. Renal artery stenosis occurred in 8 patients with AAA. Renal scintigraphy showed normal function in 19%, hypofunction in 69% and severe dysfunction in 12% of the AAA patients, and normal function in 42% and hypofunction in 58% of the HT patients (p < 0.0001). Multivariate linear regression analysis showed that renal function was related to age, UAE, CVD, smoking status and kidney size for all patients, UAE, CVD, smoking status and kidney size for AAA patients, and age and kidney size for HT patients.

CONCLUSION

Renal function of AAA patients was worse than HT patients without other CVD. The risk factors for renal dysfunction were different between AAA and HT patients. These preoperative conditions may relate to the postoperative renal dysfunction seen in AAA patients.

Stent revascularization for the prevention of cardiovascular and renal events among patients with renal artery stenosis and systolic hypertension: rationale and design of the CORAL trial

BACKGROUND

Atherosclerotic renal artery stenosis is a problem with no consensus on diagnosis or therapy. The consequences of renal ischemia are neuroendocrine activation, hypertension, and renal insufficiency that can potentially result in acceleration of atherosclerosis, further renal dysfunction, myocardial infarction, heart failure, stroke, and death. Whether revascularization improves clinical outcomes when compared with optimum medical therapy is unknown.

METHODS

CORAL is a randomized clinical trial contrasting optimum medical therapy alone to stenting with optimum medical therapy on a composite cardiovascular and renal end point: cardiovascular or renal death, myocardial infarction, hospitalization for congestive heart failure, stroke, doubling of serum creatinine, and need for renal replacement therapy. The secondary end points evaluate the effectiveness of revascularization in important subgroups of patients and with respect to all-cause mortality, kidney function, renal artery patency, microvascular renal function, and blood pressure control. We will also correlate stenosis severity with longitudinal renal function and determine the value of stenting from the perspectives of quality of life and cost-effectiveness. The primary entry criteria are (1) an atherosclerotic renal stenosis of > or = 60% with a 20 mm Hg systolic pressure gradient or > or = 80% with no gradient necessary and (2) systolic hypertension of > or = 155 mm Hg on > or = 2 antihypertensive medications. Randomization will occur in 1080 subjects. The study has 90% power to detect a 28% reduction in primary end point hazard rate.

CONCLUSIONS

CORAL represents a unique opportunity to determine the incremental value of stent revascularization, in addition to optimal medical therapy, for the treatment of atherosclerotic renal artery stenosis.

Diagnostic role of new Doppler index in assessment of renal artery stenosis

Background

Renal artery stenosis (RAS) is one of the main causes of secondary systemic arterial hypertension. Several non-invasive diagnostic methods for RAS have been used in hypertensive patients, such as color Doppler ultrasound (US). The aim of this study was to assess the sensitivity and specificity of a new renal Doppler US direct-method parameter: the renal-renal ratio (RRR), and compare with the sensitivity and specificity of direct-method conventional parameters: renal peak systolic velocity (RPSV) and renal aortic ratio (RAR), for the diagnosis of severe RAS.

Methods

Our study group included 34 patients with severe arterial hypertension (21 males and 13 females), mean age 54 (± 8.92) years old consecutively evaluated by renal color Doppler ultrasound (US) for significant RAS diagnosis. All of them underwent digital subtraction arteriography (DSA). RAS was significant if a diameter reduction > 50% was found. The parameters measured were: RPSV, RAR and RRR. The RRR was defined as the ratio between RPSV at the proximal or mid segment of the renal artery and RPSV measured at the distal segment of the renal artery. The sensitivity and specificity cutoff for the new RRR was calculated and compared with the sensitivity and specificity of RPSV and RAR.

Results

The accuracy of the direct method parameters for significant RAS were: RPSV >200 cm/s with 97% sensitivity, 72% specificity, 81% positive predictive value and 95% negative predictive value; RAR >3 with 77% sensitivity, 90% specificity, 90% positive predictive value and 76% negative predictive value. The optimal sensitivity and specificity cutoff for the new RRR was >2.7 with 97% sensitivity (p < 0.004) and 96% specificity (p < 0.02), with 97% positive predictive value and 97% negative predictive value.

Conclusion

The new RRR has improved specificity compared with the direct method conventional parameters (RPSV >200cm/s and RAR >3). Both RRR and RPSV show better sensitivity than RAR for the RAS diagnosis.

Challenges in the diagnosis and management of renal artery stenosis

Renal artery stenosis (RAS) is a common cause of secondary hypertension, with the activation of the renin-angiotensin-aldosterone system being the pathophysiologic hallmark of the disease. Renovascular hypertension, ischemic nephropathy, proteinuria, and flash pulmonary edema are the main clinical syndromes associated with RAS. The prevalence of RAS is on the rise, owing to an increasing prevalence of diabetes and atherosclerotic disease among our aging population. This rise in RAS prevalence poses major challenges for clinicians making diagnostic and treatment decisions. Although renal angioplasty is of proven benefit in fibromuscular dysplasia, randomized trials in atherosclerotic RAS have not shown any advantage for revascularization over medical therapy in terms of blood pressure control or renal function preservation. Angioplasty and surgical interventions should be reserved for patients with preserved kidney size and hemodynamically significant stenosis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Renal artery stenosis in patients with peripheral vascular disease in Kuwait

OBJECTIVE

The aim of this study was to identify the incidence of atherosclerotic renal artery stenosis (RAS) in patients with peripheral vascular disease (PVD) and its relation to any known risk factors.

SUBJECTS AND METHODS

This prospective study was conducted on 212 patients who were subjected to peripheral angiography for symptoms of PVD over a 3-year period from 1995 to 1998 at the Mubarak Al-Kabeer Hospital, Kuwait. Angiographic evidence of atherosclerotic disease and its severity was recorded in renal, abdominal aorta, iliac, femoral, popliteal and below-knee arteries. In addition, a detailed search of identifiable risk factors was done using history, clinical examination and laboratory studies.

RESULTS

The incidence of significant atherosclerotic RAS (more than 50% diameter stenosis) in patients with PVD was 15/212 (7.07%) with no significant difference in ratio between males and females (p = 0.3) compared to that of PVD alone. Patients with common iliac and femoral artery lesions had a high incidence of RAS (93.3 and 86.7%, respectively) with more than 80% probability in RAS patients with involvement of these vessels. There was significant renal impairment (p < 0.005), as assessed by serum creatinine levels, in patients with RAS compared to those who did not have it. There was a high incidence of smoking in patients with RAS (p = 0.02), and smoking was the only risk factor identified in these subjects.

CONCLUSIONS

Patients with iliac or femoral atherosclerotic disease have a high probability of associated RAS. Presence of renal impairment in patients with PVD is highly indicative of RAS. Smoking is the only identified risk factor for RAS in association with PVD in our population.

Predictors of undiagnosed renal artery stenosis among Japanese patients with risk factors of atherosclerosis

Atherosclerotic renal artery stenosis (ARAS) is a significant cause of end stage renal dysfunction (ESRD) among the elderly. Although early detection of ARAS and induction of adequate treatment could reduce the incidence of ESRD, there have been few reports about parameters predictive of ARAS among Japanese. In this study, we investigated the clinical indicators that predict ARAS among Japanese with risk factors of atherosclerosis (> 40 years of age plus hypertension, dyslipidemia or diabetes mellitus). After eliminating the patients who had already been diagnosed with renal artery stenosis, 202 patients were enrolled. The renal arteries of all 202 patients were evaluated by magnetic resonance arteriography (MRA), and the stenoses with > 50% reduction in diameter at the ostium of the renal artery were defined as ARAS. MRA detected ARAS in 42 patients (31 hemilateral and 11 bilateral). Between the patients with and without ARAS there was no significant difference in gender distribution, detection of abdominal vascular bruits or smoking habit. The prevalences of diabetic, hypertensive and cerebrovascular comorbidity were also not significantly different. The mean blood pressure, body mass index and total serum cholesterol values were similar between the two groups. However, age, pulse pressure, serum uric acid, serum creatinine, amount of urinary protein, and coronary artery comorbidity were significantly higher, while estimated creatinine clearance was significantly lower in the patients with ARAS than in those without ARAS. A high prevalence of hypertensive retinopathy was also noted among patients with ARAS. Multivariate analysis revealed that older age and renal impairment were independent predictors of ARAS in Japanese patients with atherosclerotic risk factors.

Relationship between renal artery stenosis and intrarenal damage in autopsy subjects with stroke

BACKGROUND

In patients with cardiovascular disease (CVD), renal dysfunction is a risk factor for the prognosis, but substantial evidence is still lacking about the relationship between clinical characteristics and renal histology. The aim of our study was to evaluate the relationship between the extent of renal parenchymal damage, renal artery stenosis (RAS) and clinical characteristics in autopsy subjects with stroke.

METHODS

During the 17-year period 1980-1997, 2167 subjects were autopsied at the National Cardiovascular Center. We studied retrospectively all the autopsy cases aged 40 years and older who had a history of stroke. Thus, 346 subjects remained and they were classified into two groups. Thirty-six subjects had RAS (group A). Three hundred and ten subjects had no RAS, and we randomly chose 102 subjects among them (group B). We evaluated renal parenchymal damage using a semi-quantitative chronic damage score.

RESULTS

The average overall chronic damage score was significantly higher in the stenosed kidneys of group A than in the non-stenosed kidneys of group B (9.0+/-2.6 vs 7.0+/-2.7). The contralateral kidneys of group A had a tendency to have milder renal damage than stenosed kidneys. Furthermore, the total score was higher in the subjects with hypertension, diabetes mellitus, proteinuria, renal insufficiency and CVD than in the subjects without such complications. The total score had a significant association with RAS, proteinuria, renal insufficiency, CVD and weight of the kidney.

CONCLUSIONS

In autopsy subjects with stroke, we demonstrated that co-existing renal parenchymal damage was more severe in the subjects with RAS, hypertension, diabetes mellitus, proteinuria and renal insufficiency than those without such complications. The presence of RAS, impaired renal function and proteinuria was closely correlated with the severity of renal parenchymal damage.

Atherosclerotic renal artery stenosis: current status and future directions

PURPOSE OF REVIEW

Atherosclerotic renal artery stenosis is a common, progressive problem that increases in prevalence with age. It can have important clinical consequences such as hypertension, pulmonary edema, and renal failure. In addition, it is associated with increased cardiovascular mortality. The purpose of this review is to describe the current status of knowledge and future directions for this evolving field.

RECENT FINDINGS

In patients who are suspected of having the disease, duplex Doppler ultrasound and magnetic resonance angiography remain the most promising noninvasive screening tests. Percutaneous revascularization continues to advance, and technical success is possible in the vast majority of patients. Revascularization for hypertension is of modest clinical benefit. Limited information is available on the effect of revascularization on preservation of renal function or cardiovascular events and mortality.

SUMMARY

Further studies are still needed focusing on the identification of which patients will derive benefit from percutaneous revascularization and whether intervention provides an advantage over medical therapy, particularly with respect to preservation of renal function and reduction in cardiovascular morbidity and mortality.

Renal insufficiency as a predictor of adverse events and mortality after renal artery stent placement

BACKGROUND

Renal artery stenosis (RAS) is associated with substantial morbidity and mortality. This relationship is strongest in the presence of renal insufficiency (RI). The goal of this study is to assess the relationship between RI, mortality, and adverse events in the setting of renovascular disease.

METHODS

Two hundred sixty-one patients with significant RAS treated with endovascular stenting were followed up prospectively for 21 +/- 18 months (range, 0 to 85 months). Blood pressure (BP), renal function, medication use, and comorbidities were assessed. Death was verified through the Social Security Death Master Index File, and cause of death was derived from death certificates. Medical records of 230 subjects subsequently were reviewed to identify adverse cardiovascular and renal events.

RESULTS

Overall, 37% of patients experienced at least 1 adverse event postprocedure. Myocardial infarction (MI) and congestive heart failure (CHF) events increased with degree of baseline RI. Seventy-three deaths (28%) occurred postprocedure (range, 13 to 2,457 days). Baseline characteristics associated with mortality included advanced age, decreased use of beta-blockers, increased use of diuretics, increased serum creatinine (Cr) level, decreased Cr clearance (CrCl), bilateral stenoses or stenosis of a solitary kidney, history of CHF, and history of MI. Follow-up characteristics associated with mortality included lower systolic and diastolic BP, increased serum Cr level, and decreased CrCl. RI at baseline and follow-up remained associated with mortality after adjusting for other clinically and statistically significant variables. Patients in whom renal function improved after stenting appeared to show improved survival over those without improved renal function (45% versus 0% cumulative survival, P < 0.05).

CONCLUSION

In patients with RAS undergoing stent therapy, baseline RI is associated with an increased incidence of adverse events, as well as decreased survival, independent of other baseline clinical factors. Importantly, improvement in renal function appears to be associated with increased survival.

Prevalence and predictors of renal artery stenosis in Chinese patients with coronary artery disease

BACKGROUND

Ischaemic nephropathy is currently a major public health issue in atherosclerotic populations. Although atherosclerotic cardiovascular disease in Asia has reached epidemic proportions over the last two decades, there is little published data on the prevalence of atherosclerotic renal artery stenosis (ARAS) in Oriental subjects. Because ARAS may be clinically silent until end-stage renal failure sets in, it is important to identify patients with significant but clinically unsuspected ARAS. ARAS and coronary artery disease (CAD) often coexist.

AIMS

The purpose of the present study was to evaluate the prevalence and predictors of ARAS among Chinese patients with CAD.

METHODS

A total of 230 consecutive Chinese patients with CAD confirmed by coronary angiography underwent an abdominal aortogram in the same sitting to screen for ARAS. Patient demographics and comorbidities were analysed for any association with ARAS.

RESULTS

A total of 34 (14.8%) patients was found to have significant ARAS. Age and multivessel CAD were independent predictors of ARAS. Hypertension, renal insufficiency, extracranial cerebrovascular disease and female gender were also associated with a higher risk of ARAS but did not independently predict ARAS.

CONCLUSION

Clinically silent yet angiographically significant ARAS is common among CAD patients. The prevalence and predictors of ARAS among Chinese patients with CAD are similar to those reported for Caucasian subjects. Underlying ARAS should be suspected in CAD patients with such comorbidities as hypertension, renal insufficiency, extracranial cerebrovascular disease, and more so in the elderly and those with multivessel disease.