RENAL ARTERY STENOSIS. A CLINICAL-PATHOLOGIC STUDY IN NORMOTENSIVE AND HYPERTENSIVE PATIENTS

Epigenetics of Hypertensive Nephropathy

Hypertensive nephropathy (HN) is a leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD), contributing to significant morbidity, mortality, and rising healthcare costs. In this review article, we explore the role of epigenetic mechanisms in HN progression and their potential therapeutic implications. We begin by examining key epigenetic modifications-DNA methylation, histone modifications, and non-coding RNAs-observed in kidney disease. Next, we discuss the underlying pathophysiology of HN and highlight current in vitro and in vivo models used to study the condition. Finally, we compare various types of HN-induced renal injury and their associated epigenetic mechanisms with those observed in other kidney injury models, drawing inferences on potential epigenetic therapies for HN. The information gathered in this work indicate that epigenetic mechanisms can drive the progression of HN by regulating key molecular signaling pathways involved in renal damage and fibrosis. The limitations of Renin-Angiotensin-Aldosterone System (RAAS) inhibitors underscore the need for alternative treatments targeting epigenetic pathways. This review emphasizes the importance of further research into the epigenetic regulation of HN to develop more effective therapies and preventive strategies. Identifying novel epigenetic markers could provide new therapeutic opportunities for managing CKD and reducing the burden of ESRD.

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

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

Functional Assessment of Intermediate Vascular Disease

Interventional treatment in various vascular beds has advanced tremendously. However, there are several problems to be considered. We searched the literature and tried to analyze major parts of it. One is safety and applicability of coronary proven methods in other vascular beds. An unresolved problem is the functional assessment of intermediate lesions, as far as various target organs have quite different circulation from the coronary one and the functional tests should be modified in order to be applicable and meaningful. In the majority of the acute vascular syndromes, the culprit lesion is of intermediate size on visual assessment. On the other hand, a procedurally successfully managed high-degree stenosis is not always followed by clinical and prognostic benefit. In vascular beds, where collateral network naturally exists, the readings from the functional assessment are complicated and thus the decision for interventional treatment is even more difficult. Here come into help the functional assessment and imaging with IVUS, OCT, high-resolution MRI, and contrast enhanced CT or SPECT. The focus of the current review is on the functional assessment of intermediate stenosis in other vascular beds, unlike the coronary arteries.

Atherosclerotic Renal Artery Stenosis: Should we Intervene Earlier?

Purpose of Review

Randomized trials have failed to show clinical benefit in patients with atherosclerotic renal artery stenosis who were treated with angioplasty with or without stenting. However, these studies were done in patients with a high-grade stenosis. This paper examines whether there are arguments to consider patients with low-grade stenosis for angioplasty.

Recent Findings

Patients with low-grade (< 50%) atherosclerotic renal artery stenosis have an excess risk for cardiovascular and renal complications. This could be related to inflammatory factors being generated by the stenotic kidney. Moreover, even a kidney with low-grade stenosis clears less or produces more of the natural nitric oxide inhibitor ADMA.

Summary

Patients with low-grade atherosclerotic renal artery stenosis have an increased risk for a variety of complications. In addition, the abnormality is progressive. There is a case for setting up a prospective trial to examine whether angioplasty confers benefit in patients with low-grade renal artery stenosis.

Renal artery stenosis and ambulatory blood pressure monitoring: A case report and review of the literature

Renal artery stenosis (RAS) is a prevalent cause of secondary hypertension. Elderly patients with atherosclerosis and young women with fibromuscular dysplasia (FMD) are particularly at risk. Blood pressure screening is often key to this diagnosis, although the reliability of clinical screening has been questioned, and ambulatory blood pressure monitoring (ABPM) likely offers superior ability to diagnose poorly controlled hypertension. In patients with RAS, medical management should be the primary means of therapy; however, in a select group of these patients, renal revascularization may be considered, and has been shown to reduce blood pressure and stabilize chronic kidney disease. In this report, we present a patient diagnosed with RAS due to FMD, found to have significant hypertension via ABPM, and treated successfully with percutaneous renal artery angioplasty; importantly, continuous 24-hr ambulatory monitoring after pressure gradient guided renal angioplasty confirmed reduction in blood pressure.

Use of Embolic Protection Devices in Peripheral Interventions

The use of embolic protection devices (EPDs) when treating coronary saphenous vein bypass grafts, performing carotid arterial stenting and treating acute coronary syndromes is well accepted. We will review currently available devices and approaches to reduce distal embolisation, first discussing their uses in carotid interventions and then in vertebral and peripheral vascular interventions.

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

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

Radionuclides in nephrourology, Part 2: pitfalls and diagnostic applications

Radionuclide renal scintigraphy provides important functional data to assist in the diagnosis and management of patients with a variety of suspected genitourinary tract problems, but the procedures are underutilized. Maximizing the utility of the available studies (as well as the perception of utility by referring physicians) requires a clear understanding of the clinical question, attention to quality control, acquisition of the essential elements necessary to produce an informed interpretation, and production of a report that presents a coherent impression based on data contained in the report and that specifically addresses the clinical question. To help achieve these goals, part 1 of this review addressed the available radiopharmaceuticals, quality control, and quantitative indices, including the measurement of absolute and relative renal function. Part 2 assumes familiarity with part 1 and focuses on the common clinical indications of suspected obstruction and renovascular hypertension; part 2 also summarizes the status of radionuclide renal imaging in the evaluation of the transplanted kidney and the detection of infection, discusses potential pitfalls, and concludes with suggestions for future research. The series of SAM questions accompanying parts 1 and 2 has been designed to reinforce and extend points made in the review. Although the primary focus is the adult patient, aspects of the review also apply to the pediatric population.

The current status of angioplasty of atherosclerotic renal artery stenosis for the treatment of hypertension

Atherosclerotic renal artery stenosis, a fairly common disease of older persons, is a manifestation of generalized atherosclerosis, and is often associated with coronary artery disease. It is frequently associated with hypertension and impaired renal function, and is perceived by many physicians to be the cause of hypertension and renal failure. For this reason, they believe that hypertension can be cured by performing percutaneous renal artery angioplasty (PTRA) with stent placement. This practice has led to an increase in angioplasties, especially by interventional cardiologists, although the results from several randomized studies comparing interventional therapy with medical therapy have shown no significant difference between the two treatment modalities in blood pressure reduction or change in renal function. Similar results have been found by nonrandomized trials with selective PTRA. For this review, a Medline search of the English literature was conducted from 2006 to 2012, and 13 pertinent studies were selected. These studies with collateral literature will be discussed in this concise review.

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Prevalence of renal artery stenosis in subjects with moderate hypertension. A population-based study

AIM

To examine the prevalence of significant renal artery stenosis (RAS) in subjects with moderate to severe hypertension.

MATERIALS AND METHODS

Subjects aged 50-66 years with blood pressure >160/100 mmHg or receiving antihypertensive treatment were selected from the population study Inter99. We examined 332 subjects (209 men, 123 women) for RAS >50% of diameter with Doppler-US. Subjects with RAS were re-examined 2 years later. Furthermore, we report sensitivity and specificity of the screening method based on consecutive examinations of 100 patients before referral to renal angiography.

RESULTS

The sensitivity and specificity of the Doppler US examination for the detection of RAS was 98% and 96%, respectively. Unilateral RAS was found in 11 subjects. Nine were women. The prevalence of RAS in the examined population was 3.3% (men: 0.9%, women: 7.3%). One patient was referred to balloon angioplasty. Two patients had reduced size and function of the affected kidney. Among the non-invasively treated patients, one showed stenosis progression at the 2-year follow-up examination.

CONCLUSION

In subjects aged 50-66 years with hypertension grade II-III, RAS is rare among men, but not among women. These women may suffer from fibromuscular dysplasia. They are at risk of losing kidney function and developing severe hypertension, but they would not have been considered for screening according to present criteria.

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.

Atherosclerotic renal artery stenosis: current therapy and future developments

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

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

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

Renal artery stenosis and chronic ischemic nephropathy: epidemiology and diagnosis

Atherosclerotic renal artery stenosis (RAS) is the most common primary disease of the renal arteries and results in renovascular hypertension and ischemic nephropathy. Ischemic nephropathy from atherosclerotic RAS is increasingly recognized as a cause of chronic kidney disease (CKD) and in severe cases can lead to end-stage renal disease. The exact prevalence of atherosclerotic RAS is unknown because the disease is often asymptomatic and few are screened unless they have significant traditional cardiac risk factors or symptoms. A high prevalence of atherosclerotic RAS is seen in patients with advanced age, congestive heart failure, and extrarenal atherosclerosis. The primary reason for diagnosing ischemic nephropathy from renovascular disease is that the loss of kidney function is potentially reversible through treatment of the occlusion with surgical revascularization or percutaneous transluminal renal angioplasty. However, the benefits of revascularization have to be considered in the context of other comorbid disease and remain controversial. There are several tests available for the screening and diagnosis of atherosclerotic RAS; however, the diagnostic test of choice should be based on patient factors and institutional expertise because the best test is the one performed most often at the individual medical facility.

Treatment of renovascular hypertension by transluminal angioplasty--13 years experience in a single centre

OBJECTIVE

The study is a follow-up on treatment of renovascular hypertension (RVH) with percutaneous transluminal renal angioplasty (PTRA).

METHODS

Patients were screened on the basis of clinical criteria of increased probability of RVH with renography and in selected cases with renal vein renin measurements. A positive work-up suggesting a functionally important renal artery stenosis led to renal angiography and PTRA if stenosis was confirmed; in 59%, an intravascular stent was inserted.

RESULTS

Outcome of treatment was classified as follows - group I: normotensive without medication; group II: with improved control of blood pressure; group III: unchanged blood pressure control. Grouping was performed immediately after treatment, at 1 month, 6 months and at the latest follow-up. One hundred-and-twenty-two patients (124 atherosclerotic and 12 fibromuscular lesions) were treated during 13 years. Immediately after PTRA the patients were grouped as follows - I: 31%, II: 59%, III: 10%. At 1 month, I: 13%, II: 72%, III: 15%; at 6 months, I: 11%, II: 74%, III: 15%, and at the latest follow-up, I: 11%, II: 78%, III: 11%. There were few significant complications, and renal function remained on average stable.

CONCLUSION

PTRA is an effective treatment of RVH in patients selected by signs of a flow-restricting stenosis. Twelve percent were normotensive after angioplasty and a further 77% had better controlled hypertension. Few complications were seen and renal function was on average unchanged as measured by serum creatinine.

[Abdominal aortic aneurysm and renovascular disease]

Recent technological advances in the diagnosis and therapy of abdominal aortic aneurysm and renovascular disease are continuing to bring about changes in the way patients suffering from these conditions are treated. The prevalence of both these conditions is increasing. This is due to greater life-expectancy in patients with arteriosclerosis, a pathogenetic factor underlying both conditions. The application of diagnostic imaging techniques to non-vascular conditions has led to the early diagnosis of abdominal aortic aneurysm. Clinical suspicion of reno-vascular disease can be confirmed easily using high-resolution diagnostic imaging modalities such as CT angiography and magnetic resonance angiography. Endovascular intervention is successfully replacing conventional surgical repair techniques, with the result that it may be possible to improve outcome in both conditions using effective and minimally invasive approaches. Future technological developments will enable these endovascular techniques to be applied in the large majority of patients with abdominal aortic aneurysm or renovascular disease.

Multidetector spiral CT renal angiography in the diagnosis of renal artery fibromuscular dysplasia

OBJECTIVE

The aim of this study was to evaluate the role and detection rate of multidetector spiral CT renal angiography (CTA) as compared with conventional angiography (CA), the commonly accepted gold standard, in the diagnosis of renal artery fibromuscular dysplasia (FMD). In addition, the role of CTA reconstructions (multiplanar reformatted images (MPR), maximum intensity projections (MIP) and shaded-surface display (SSD)) in the detection of FMD was also evaluated.

MATERIALS AND METHODS

CTA results were retrospectively reviewed in 21 hypertensive patients with CA-proven FMD. Clinical indications for referral included resistant hypertension (requiring greater than three antihypertensive medications), labile hypertension, hypertension in combination with renal impairment and the presence of abdominal bruits in the context of systemic hypertension. In some cases, these clinical indications were supplemented by positive results in other tests, including plasma renin assay, captopril scintigraphy and/or Doppler ultrasound. The findings of CA in these 21 patients were compared to CTA.

RESULTS

Mean patient age was 62.33+14.32 years (range 24-85 years). CTA identified all 42 main renal arteries (100%) and all 10 accessory renal arteries (100%) visualized on CA. In the diagnosis of FMD, CTA detected all 40 (100%) lesions detected by CA. No single CTA reconstruction technique was able to detect all lesions noted on corresponding CA, however, upon review of all CTA reconstructions (MPR, MIP and SSD) in each case, every lesion was correctly identified by CTA.

CONCLUSION

Our experience suggests that CTA is a non-invasive, reliable and accurate method for the diagnosis of renal artery fibromuscular dysplasia. Moreover, in our experience CTA has many advantages as a diagnostic screening tool over CA, including accessibility, speed, lower complication profile, versatility and cost-effectiveness. CTA shows great potential as a guiding tool for directing subsequent procedures such as CA+balloon angioplasty.

Renal artery stenosis and accelerated atherosclerosis: which comes first?

Renal artery stenosis (RAS) is usually observed in hypertensive patients with extensive atherosclerosis. There is some evidence that in these patients the atherosclerotic process and the consequent target-organ damage is more severe than in hypertensive patients without RAS. In this review we will entertain the hypothesis that some of the humoral factors that are activated by RAS may contribute to accelerate the progression of atherosclerosis. Several studies identified RAS as a predictor of cardiovascular events in high-risk patients, although in most cases the contribution of blood pressure per se to the progression of vascular lesions could not be determined. As a result of experimental RAS, hypertension and increased oxidative stress are stimuli for atherosclerosis as well as cardiac and renal damage. In the presence of RAS, the renin-angiotensin system is stimulated, and it has been shown that angiotensin II exerts proinflammatory, pro-oxidant and procoagulant activities in experimental models and humans. The potential contribution of reactive oxygen species to the prohypertensive and proatherosclerotic effects of RAS is supported by evidence that nicotinamide adenine dinucleotide phosphate, reduced form oxidase is specifically stimulated by angiotensin II, an activity not shared by epinephrine. Moreover, angiotensin II triggers the release of aldosterone, endothelin 1, thromboxane A2 and other derivatives of the arachidonic acid metabolism, all of which can further and independently aggravate cardiovascular damage. Epidemiological and experimental evidence so far available suggests that accelerated atherosclerosis can be both the cause and the consequence of RAS.

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.

Clinical insights into the diagnosis and management of atherosclerotic renal artery disease

Atherosclerotic renovascular disease (ARVD) is an increasingly common contributor to hypertension and renal failure. However, not all patients with an identified obstructive atherosclerotic renal artery stenosis will have clinical improvement, even after successful percutaneous intervention. As such, there remains extensive controversy regarding optimal diagnostic and treatment strategies. Part of this controversy is the result of a paucity of well-designed prospective, randomized clinical trials, but the complex nature of the disorder and the heterogeneity of patients presenting with possible ARVD make simple diagnostic and treatment paradigms difficult to develop. This narrative review describes the latest observations concerning the prevalence, pathogenesis, natural history, diagnostic studies, and treatment options for suspected ARVD. Hopefully, this knowledge will improve the ability of clinicians to weigh risks and benefits and determine the best strategy in individual patients.

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.

Losartan renography for the detection of renal artery stenosis: comparison with captopril renography and evaluation of dose and timing

PURPOSE

Radionuclide renography with angiotensin converting enzyme (ACE) inhibition plays an important role in the diagnosis of haemodynamically significant renal artery stenosis. Angiotensin receptor antagonists inhibit the renin angiotensin system at different levels from ACE inhibitors by selectively blocking the binding of angiotensin II to AT1 receptors. The AT1 angiotensin receptor antagonist losartan has recently been used clinically in the treatment of hypertension. However, the available data on the use of losartan with renography for the detection of renovascular hypertension are limited and contradictory. The purpose of this prospective study was to compare the effectiveness of losartan renography and captopril scintigraphy in revealing renal artery stenosis.

METHODS

A total of 61 renal units in 32 patients with hypertension were studied in two groups based on the losartan dosage (50 mg in group A and 100 mg in group B). Group A consisted of 17 patients, in whom 19 renal units had angiographically proven renal artery stenosis (>or=50%). In group B, there were 15 patients, in whom 20 renal arteries were stenotic. All of the patients underwent three renographies (baseline, captopril renography and early losartan renography). Early losartan renography was performed at 1 h after oral losartan administration in both groups. In group B, seven patients underwent additional losartan renography (late losartan) performed 3 h after oral losartan administration; these patients composed group B1.

RESULTS

The sensitivities of captopril and losartan studies were 63.2% and 42% in group A, 65% and 65% in group B and 55.6% and 66.6% in group B1, respectively.

CONCLUSION

From our preliminary results, we conclude that losartan is not superior to captopril renography for the detection of haemodynamically significant renal artery stenosis. However, a high dose (100 mg) of losartan provided higher sensitivity than the lower dose (50 mg). Late losartan scintigraphy provided similar diagnostic efficacy to early losartan renography.

Associations between renovascular disease and prevalent cardiovascular disease in the elderly: a population-based study

Atherosclerotic renovascular disease (RVD) is a suspected contributor to the morbidity and mortality of cardiovascular disease (CVD) through its potential effects on blood pressure and excretory renal function as well as through its associations with other forms of CVD. However, population-based data regarding the associations between the presence of RVD and prevalent CVD are lacking. The Cardiovascular Health Study (CHS) is a prospective, multicenter cohort study of CVD among elderly Americans. As part of an ancillary study, participants in the Forsyth County, North Carolina, cohort of the CHS were invited to undergo renal duplex sonography (RDS) to establish the presence or absence of RVD (defined as any focal peak systolic velocity >/= 1.8 m/second or the absence of a Doppler-shifted signal from an imaged artery). Demographic, risk factor, and prevalent CVD data were obtained from the CHS coordinating center and matched with ancillary study participants. Eight hundred thirty-four CHS participants (including 525 women [63%], 309 men [37%], 194 African-Americans [23%], and 635 Caucasians [76%]) with a mean age of 77.2 +/-4.9 years underwent RDS examination. RVD was present in 57 participants (6.8%). Overall, clinical and/or subclinical manifestations of CVD were present in 603 participants (72.3%) at the time of RDS. Participants with RVD demonstrated a significantly greater prevalence of angina (p = 0.002), previous myocardial infarction (p < 0.001), >/= 25% diameter-reducing internal carotid artery stenosis (p = 0.010), increased carotid intimal medial thickness (p = 0.003), and major electrocardiographic abnormalities (p = 0.013). Following adjustment for demographics and cardiovascular risk factors, the presence of RVD demonstrated a significant and independent association with prevalent coronary artery disease but not with prevalent cerebrovascular or lower extremity vascular disease. These results suggest important population-based associations between RVD and both clinical and subclinical manifestations of CVD, especially coronary artery disease.

Prevalence of renal artery stenosis in high-risk veterans referred to cardiac catheterization

OBJECTIVE

The prevalence of atherosclerotic renal artery stenosis (RAS) varies depending on patient selection with no specific guidelines on indications for selective renal angiography in patients referred for coronary angiography. The goal of this study is to determine the prevalence and predictors of renal artery stenosis in hypertensive veterans referred for coronary angiography.

DESIGN

Prospective study.

SETTING

Tertiary care veterans' administration facility in the USA.

PATIENTS, PARTICIPANTS

A total of 90 veterans referred for coronary angiography with an initial ascending aortic pressure > 135 mmHg.

INTERVENTIONS

Selective renal angiography was performed following coronary angiography.

RESULTS

We found that 28% of the patients had single RAS (> or = 50% stenosis), while 16% had single RAS > or = 70% stenosis, 10% had bilateral RAS >or = 50% and 6% had bilateral RAS > or = 70%. Significant positive univariate predictors of RAS (> or = 50%) were age, peripheral vascular disease (PVD), creatinine level (Cr) and myocardial infarction. Significant multivariate predictors of RAS (> or = 50%) were age > 65 years [relative risk (RR), 3.6; 95% confidence interval (CI), (1.2-10.6)], PVD [RR 3.2, 95% CI (1.1-9.1)] and Cr > 1 mg/dl [RR 4.9, 95% CI (1.53-15.9)]. No complications related to renal angiography were noted.

CONCLUSIONS

Selective renal angiography during routine coronary angiography in hypertensive veterans with coronary artery disease is safe and uncovers RAS in many older patients with PVD and renal insufficiency.

The diagnosis and management of renovascular disease: a primary care perspective. Part I. Making the diagnosis

Renovascular disease is a complex disorder, the most common causes of which are fibromuscular dysplasia and atherosclerotic disease. It usually presents in one of three forms: asymptomatic renal artery stenosis, renovascular hypertension, or ischemic nephropathy. This complexity often makes diagnostic and management decisions difficult. This review will be presented in two parts. In Part I, the authors will discuss when to consider and how to go about making the diagnosis. In Part II (in a future issue of The JCH), the authors discuss the management of renovascular disease. The clinical index of suspicion remains paramount in setting the diagnostic strategy. Although it is subject to certain limitations, conventional contrast angiography is usually considered the gold standard in confirming the diagnosis. In addition, there are a number of available noninvasive tests that can aid in decision making. These tests can be divided into those that detect the anatomic presence of a stenosis and those that identify the functional consequences of the renal artery obstruction. No one study is appropriate for every patient. A diagnostic algorithm is proposed at the conclusion of this review.

Relationships between renovascular disease, blood pressure, and renal function in the elderly: a population-based study

BACKGROUND

The purpose of this study is to examine the associations between renovascular disease (RVD) and cross-sectional measures of blood pressure and renal function among participants in the Cardiovascular Health Study (CHS).

METHODS

The CHS is a prospective cohort study of cardiovascular disease among elderly Americans. As part of an ancillary study, participants in the Forsyth County, NC, cohort of the CHS were invited to undergo renal duplex sonography (RDS) to define the presence or absence of RVD (defined as any focal peak systolic velocity > or = 1.8 milliseconds or the absence of a Doppler shifted signal from an imaged artery). Demographic, risk factor, blood pressure, and serum creatinine data were obtained at the time of RDS and from the annual CHS examination.

RESULTS

Eight hundred thirty-four CHS participants (including 525 women [63%], 309 men [37%], 194 African Americans [23%], and 635 Caucasians [76%]) with a mean age of 77.2 +/- 4.9 years underwent successful RDS. RVD was present in 57 participants (6.8%). When examined according to the presence or absence of RVD, significant univariate differences were observed in the prevalence of clinical hypertension (72% versus 50%; P = 0.001), systolic blood pressure (145 versus 136 mm Hg; P = 0.001), and renal insufficiency (16% versus 8%; P = 0.041). Multivariate analyses showed significant and independent associations for the presence of RVD with increasing systolic blood pressure (P = 0.034), clinical hypertension (odds ratio, 2.68; 95% confidence interval, 1.44 to 4.99; P = 0.002), increasing serum creatinine level, and renal insufficiency (odds ratio, 2.21; 95% confidence interval, 1.02 to 4.79; P = 0.043). A significant interaction was observed between the presence of RVD and increasing systolic blood pressure in association with increasing serum creatinine levels (P = 0.041).

CONCLUSION

These results suggest important population-based associations between RVD and cross-sectional measures of blood pressure and renal function. Furthermore, the observed relationship between RVD and increasing serum creatinine level was influenced strongly by increasing blood pressure.

Atherosclerotic ischemic renal disease. Diagnosis and prevalence in an hypertensive and/or uremic elderly population

BACKGROUND

Atherosclerotic ischemic renal disease is a frequent cause of end-stage renal failure leading to dialysis among the elderly; Its prevalence is inferred from autopsy or retrospective arteriographic studies. This study has been conducted on 269 subjects over 50 with hypertension and/or CRF, unrelated to other known causes of renal disease.

METHODS

All 269 patients were studied either by color-flow duplex sonography (n = 238) or by renal scintigraphy (n = 224), and 199 of the 269 patients were evaluated using both of these techniques. 40 patients, found to have renal artery stenosis (RAS), were subjected to 3D-contrast enhancement Magnetic Resonance Angiography (MRA) and/or Selective Angiography (SA). An additional 23 cases, negative both to scintigraphy and to ultrasound study, underwent renal angiography (MRA and/or SA).

RESULTS

Color-duplex sonography, carried out in 238 patients, revealed 49 cases of RAS. MR or SA was carried out in 35 of these 49 patients, and confirmed the diagnosis in 33. Color-duplex sonography showed a PPV value of 94.3% and NPV of 87.0% while renal scintigraphy, carried out in 224 patients, had a PPV of 72.2% and a NPV of 29.4%. Patients with RAS showed a higher degree of renal insufficiency compared to non stenotic patients while there were no differences in proteinuria. RAS, based on color-duplex sonography studies, was present in 11% of patients in the age group 50-59, 18% in the 60-69 and 23% at age 70 and above.

CONCLUSIONS

A relatively large percentage of the elderly population with renal insufficiency and/or hypertension is affected by RAS and is at risk of developing end-stage renal failure. Color-duplex ultrasonography is a valid routine method of investigation of population at risk for renal artery stenosis.

Urological manifestations of vascular disease

We have detailed several of the urological manifestations of vascular disease. With the aging of the North American population, urologists will encounter the urological complications of vascular disease with ever-increasing frequency.

Chronic renal ischemia: implications for cardiovascular disease risk

Chronic renal ischemia caused by atherosclerotic renal artery stenosis (RAS) is gaining recognition as a potentially important risk factor for cardiovascular (CV) morbidity and mortality. The etiology of increased risk of CV events is multifaceted and includes direct physiologic changes that increase risk as well as intermediate clinical effects that are associated with worse outcome. Physiologic changes associated with increased CV risk in patients with RAS include increased production of fibrogenic and vasoactive peptides such as renin, angiotensin, endothelin, and catecholamines, as well as endothelial cell dysfunction. Clinical intermediate conditions associated with higher incidences of CV events seen in patients with renal ischemia include hypertension, systemic atherosclerosis, chronic renal failure, and left ventricular hypertrophy and dysfunction. More thorough understanding of the myriad physiologic changes seen in patients with RAS will likely improve patient selection for renal artery revascularization. Clinical trials should examine a full range of CV and renal outcomes, not just blood pressure, to adequately assess the merits of revascularization.

Atherosclerotic renal artery stenosis: epidemiology, cardiovascular outcomes, and clinical prediction rules

Atherosclerotic renal artery stenosis is the most common primary disease of the renal arteries, and it is associated with two major clinical syndromes, ischemic renal disease and hypertension. The prevalence of this disease in the population is undefined because there is no simple and reliable test that can be applied on a large scale. Renal artery involvement in patients with coronary heart disease and/or heart failure is frequent, and it may influence cardiovascular outcomes and survival in these patients. Suspecting renal arterial stenosis in patients with recurrent episodes of pulmonary edema is justified by observations showing that about one third of elderly patients with heart failure display atherosclerotic renal disease. Whether interventions aimed at restoring arterial patency may reduce the high mortality in patients with heart failure is still unclear because, to date, no prospective study has been carried out in these patients. Increased awareness of the need for cost containment has renewed the interest in clinical cues for suspecting renovascular hypertension. In this regard, the DRASTIC study constitutes an important attempt at validating clinical prediction rules. In this study, a clinical rule was derived that predicted renal artery stenosis as efficiently as renal scintigraphy (sensitivity: clinical rule, 65% versus scintigraphy, 72%; specificity: 87% versus 92%). When tested in a systematic and quantitative manner, clinical findings can perform as accurately as more complex tests in the detection of renal artery stenosis.