Prevalence of renal artery stenosis in autopsy patients with stroke

Therapy for Renal Artery Stenosis: A Call for Change

CLINICAL IMPACT

We present a brief case description of a patient who benefitted from stenting in ARAS and provide a comprehensive review of ARAS; its prevalence, pathophysiology, clinical manifestations, diagnosis and treatment. We review the evidence for and against stenting in ARAS as well as consensus guidelines for stenting. Our review is valuable as we argue that stenting in ARAS is underutilized and the randomized control data for stenting in those patients who may benefit most is lacking. Our review will provide an important perspective for clinicians faced with decisions of how to treat ARAS.

Ten-Year Outcomes in Patients Undergoing Simultaneous Coronary and Renal Angiography-Does Renal Artery Stenosis Matter?

Background: We aimed to characterize the population of consecutive patients undergoing coronary angiography with simultaneous renal artery angiography and assess prognostic factors at a 10 year follow-up. Methods: The KORONEF study was a prospective, single-center, observational, and descriptive study with 492 patients included. We analyzed several baseline demographics, clinical and periprocedural characteristics, and laboratory data, and we assessed the results of coronary angiography and renal artery angiography. Results: The study population consisted of 37.2% women, and the mean age was 64.4 ± 9.9 years (min. 30 years, max. 89 years). Angiography revealed significant renal artery stenosis (RAS) in 35 (7.1%) patients. Among patients with significant RAS (≥50%), we observed more women (57.1% vs. 35.7%, p = 0.011), and patients were older (69.1 ± 10.4 years vs. 64.0 ± 9.7 years, p = 0.005). In the whole population, all-cause death was reported in 29.9% of patients, myocardial infarction (MI) rate-in 11.8%, and stroke-in 4.9%. In the multivariable analysis, independent predictors of death were age 65-75 years (HR 2.88), age > 75 years (HR 8.07), diabetes (HR 1.59), previous MI (HR 1.64), chronic kidney disease (HR 2.22), unstable angina (HR 0.37), and left ventricular ejection fraction > 60% (HR 0.43). Conclusions: Over a 10 year follow-up, the all-cause death rate was 29.9%, showing no statistically significant differences between patients with and without significant RAS.

Correlation and risk factors of peripheral and cervicocephalic arterial atherosclerosis in patients with ischemic cerebrovascular disease

Patients with ischemic cerebrovascular disease (ICVD) frequently develop concomitant peripheral artery disease (PAD) or renal artery stenosis (RAS), and multiterritorial atherosclerotic patients usually have a worse prognosis. We aimed to evaluate the status of peripheral atherosclerosis (AS) and cervicocephalic AS (CAS) in ICVD patients with AS, their correlation, and related risk factors contributing to coexisting cervicocephalic-peripheral AS (CPAS). Based on the severity and extent of AS evaluated by computed tomography angiography and ultrasound, the degree of AS was triple categorized to assess the correlation between CAS and PAD/RAS. CAS and PAD/RAS were defined as the most severe stenosis being ≥ 50% luminal diameter in cervicocephalic or lower limb arteries, and a peak systolic velocity at the turbulent site being ≥ 180 cm/s in the renal artery. Among 403 patients with symptom onset within 30 days, CAS, PAD, and RAS occurrence rates were 68.7%, 25.3%, and 9.9%, respectively. PAD was independently associated with the degree of extracranial and intracranial CAS (p = 0.042, OR = 1.428, 95% CI 1.014-2.012; p = 0.002, OR = 1.680, 95% CI 1.206-2.339), while RAS was independently associated with the degree of extracranial CAS (p = 0.001, OR = 2.880, 95% CI 1.556-5.329). Independent CPAS risk factors included an ischemic stroke history (p = 0.033), increased age (p < 0.01), as well as elevated fibrinogen (p = 0.021) and D-dimer levels (p = 0.019). In conclusion, the occurrence rates of RAS and PAD in ICVD patients with AS is relatively high, and with the severity of RAS or PAD increase, the severity of CAS also increase. Strengthening the evaluation of peripheral AS and controlling elevated fibrinogen might be crucial for preventing and delaying the progression of multiterritorial AS in ICVD patients with AS, thereby improving risk stratification and promoting more effective prevention and treatment strategies.

Gray-Scale, Color Doppler, Spectral Doppler, and Contrast-Enhanced Renal Artery Ultrasound: Imaging Techniques and Features

Renal artery stenosis (RAS) is increasingly being detected in elderly patients as life expectancy increases. RAS induces hypertension or reduces renal function. Computed tomography or magnetic resonance angiography are objective in detecting RAS but may cause iodine-induced nephrotoxicity or nephrogenic systemic fibrosis in patients with RAS. Ultrasound (US) is, by contrast, a noninvasive and real-time imaging modality useful in patients with reduced renal function. Renal US is not as sensitive for detecting RAS because this technique indirectly assesses the renal artery by analyzing intrarenal hemodynamic changes. Although, ideally, US would be used to directly evaluate the renal artery, its current utility for RAS detection remains unclear. The purpose of this review is to introduce how to assess renal artery with US, to describe imaging features of renal artery US, to compare renal artery US and renal US, and to show how to perform work-up in patients in whom RAS is suspected.

Atherosclerotic Renal Artery Stenosis: A Review

Renal artery stenosis (RAS) is associated with hypertension and renal impairment. Atherosclerosis is the leading etiologic factor which accounts for >90% of the cases. Those with atherosclerotic RAS (ARAS) tend to have concomitant atherosclerosis in other vascular beds, so they are at a high risk of adverse coronary and cerebrovascular events. Management of ARAS is controversial, with limited indications for revascularization. In this review, the author aims to discuss the pathophysiology, natural history, diagnosis, and management of ARAS.

Intermittent claudication and severe renal artery stenosis are independently associated in hypertensive patients referred for renal arteriography

OBJECTIVE:

The purpose of this study was to evaluate the association between the presence of clinical symptoms of peripheral artery disease and severe renal artery stenosis in patients referred for renal angiography.

METHOD:

We included 82 patients with clinical suspicion of renovascular hypertension and performed an imaging investigation (renal Doppler ultrasound and/or renal scintigraphy) for possible renal artery stenosis. All patients underwent renal arteriography and were examined for peripheral artery disease based on the presence of intermittent claudication and ankle-brachial index test results. Severe renal artery stenosis was defined as a lesion causing 70% obstruction.

RESULTS:

Severe renal artery stenosis was present in 32 of 82 (39%) patients. Patients with severe renal artery stenosis were older (63±12 vs 56±12 years, p=0.006), had more intermittent claudication (55 vs 45%, p=0.027), and had a greater prevalence of an ankle-brachial index <0.9 (44% vs 20%, p=0.021) than patients without severe renal artery stenosis. Multivariate logistic regression analysis showed that the presence of intermittent claudication was independently associated with renal artery stenosis ≥70% (OR: 3.33; 95% CI 1.03-10.82, p=0.04), unlike the ankle-brachial index, which showed no association (OR: 1.44; 95% CI 0.37-5.66, p=0.60).

CONCLUSION:

Intermittent claudication is independently associated with severe renal artery stenosis (≥70%) in patients clinically suspected of having renovascular hypertension.

Study of pomegranate (Punica granatum L.) peel extract containing anthocyanins on fatty streak formation in the renal arteries in hypercholesterolemic rabbits

BACKGROUND

The influence of the supplementation of pomegranate peel extract containing anthocyanins on atherosclerotic plaque formation induced by hypercholesterolemia was investigated in renal arteries in rabbits.

MATERIALS AND METHODS

After the determination of polyphenol and anthocyanin's content of P. granatum peel hydroalcoholic extract, 30 male rabbits were randomly divided into three groups. They were fed basic diet, hypercholesterolemic diet and hypercholesterolemic diet along with P. granatum peel extract (polyphenolic content for each rabbit 1 g/kg diet) for 2 month. Blood samples were collected at the begging, middle and end of the study in order to measure lipid concentration and oxidative and antioxidative status variables, and renal arteries were taken for the assessment of atherosclerotic plaques at the end of the study.

RESULTS

The results reveal that P. granatum peel extract significantly increases serum antioxidant capacity in the extract recipient group in comparison with hypercholesterolemic control (P < 0.05). No significant differences are observed in total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, very low-density lipoprotein and in mean size of accumulated fatty streaks in renal arteries in the extract treatment group in comparison with hypercholesterolemic control (P > 0.05).

CONCLUSION

The results of this study indicate that consumption of pomegranate peel extract containing anthocyanins (polyphenol content 1 g/kg diet) despite of a significant increase in serum antioxidant capacity cannot protect the kidneys from hypercholesterolemia-induced damages during the treatment period.

Risks for mortality and renal replacement therapy in atherosclerotic renovascular disease compared with other causes of chronic kidney disease

AIM

Patients with atherosclerotic renovascular disease (ARVD) have an increased risk for death and likelihood of initiating renal replacement therapy (RRT) compared with the general population. No data exist to describe prognosis in ARVD compared with other causes of chronic kidney disease (CKD). We compare patient outcomes between ARVD and other causes of CKD.

METHODS

Patients were selected from two prospective observational cohort studies of outcome in ARVD and CKD. Multivariate Cox regression was used to compare risk for RRT and death (both prior to and following initiation of RRT) between patients with ARVD and other causes of CKD.

RESULTS

Of 1472 patients (563 (38%) ARVD, 909 (62%) non-ARVD), 242 (16%) progressed to RRT and 640 (44%) died over a median follow-up period of 4.1 (2.4-5.6) years. Patients with ARVD had an increased risk for death (HR 1.5 (1.2-1.8), P < 0.001) but not for RRT (HR 1.0 (0.7-1.4), P = 0.9). The largest increase in risk for death was observed relative to renal limited diseases, e.g. pyelonephritis (HR 2.4 (1.3-4.5), P = 0.004) and interstitial/infiltrative disease (HR 2.2 (1.3-4.5), P = 0.02). Following initiation of RRT, patients with ARVD had a significantly increased risk for death compared with patients without ARVD (HR 3.3 (2.2-5.0), P < 0.001).

CONCLUSIONS

Patients with ARVD as a cause of CKD have an increased risk for death both prior to and following initiation of RRT. Further work should seek to identify modifiable risk factors relevant to prognosis.

Extrarenal atherosclerotic disease blunts renal recovery in patients with renovascular hypertension

BACKGROUND

Atherosclerotic renovascular disease (ARVD) is associated with high rates of coronary events and predicts mortality among patients with coronary artery disease (CAD). However, the impact of coronary atherosclerosis on renal outcomes after revascularization of ARVD is unclear. We hypothesized that CAD negatively impacts renal functional outcomes among patients with ARVD undergoing renal artery revascularization.

METHODS

Patients with ARVD who underwent echocardiography at Mayo Clinic, Rochester, Minnesota, USA between 2004 and 2012 were identified retrospectively and included if they had ejection fraction more than 50%. Renal and overall outcomes were compared among atherosclerotic renovascular disease patients with coronary artery disease (ARVD-C, n = 75) and without coronary artery disease (ARVD, n = 56), within 1 year from initial revascularization and included blood pressure control, renal function, and incident cardiovascular/cerebrovascular events.

RESULTS

Degree of renal artery stenosis was similar in both groups. ARVD-C had higher prevalence of diabetes, peripheral artery disease (PAD), and cerebrovascular disease, and lower baseline renal function. Risk of developing end-stage renal disease was higher in ARVD-C (11 vs. 2%, P = 0.05). Despite better control of blood pressure and cholesterol levels, renal function postrevascularization worsened in 15% of ARVD-C compared with 2% of ARVD (P = 0.01). Differences in clinical outcomes remained statistically significant after adjustment for covariables, including sex, baseline blood pressure, renal function, underlying diabetes, cholesterol levels, and medications. Similar differences in clinical outcomes were also associated with PAD and cerebrovascular disease.

CONCLUSION

CAD in patients with ARVD is a predictor of worse outcomes after renal revascularization, likely reflecting diffuse atherosclerotic disease. Further studies are needed to develop strategies to manage patients with vascular comorbidities and improve their outcomes.

Management of Renal Arterial Disease

Severe atherosclerotic renal artery stenosis can manifest as treatment-resistant hypertension, ischemic nephropathy and/or cardiac disturbance syndromes of recurrent flash pulmonary edema and refractory angina. Renal artery revascularization can dramatically impact patient outcome. However, patient selection for revascularization can be challenging. Renal artery stenting is most commonly used for renal revascularization and is a safe procedure when performed in carefully selected patients. This review addresses the pathophysiology of renal artery stenosis and the data supporting revascularization in such patients.

Renal artery stenosis: epidemiology and treatment

Renal artery stenosis (RAS) is a frequently encountered problem in clinical practice. The disease encompasses a broad spectrum of pathophysiologies and is associated with three major clinical syndromes: ischemic nephropathy, hypertension, and destabilizing cardiac syndromes. The two most common etiologies are fibromuscular dysplasia and atherosclerotic renal artery disease with atherosclerotic disease accounting for the vast majority of cases. Atherosclerotic renovascular disease has considerable overlap with atherosclerotic disease elsewhere and is associated with a poor prognosis. A wide range of diagnostic modalities and treatment approaches for RAS are available to clinicians, and with the advent of endovascular interventions, selecting the best course for a given patient has only grown more challenging. Several clinical trials have demonstrated some benefit with revascularization but not to the extent that many had hoped for or expected. Furthermore, much of the existing data is only marginally useful given significant flaws in study design and inherent bias. There remains a need for further identification of subgroups and appropriate indications in hopes of maximizing outcomes and avoiding unnecessary procedures in patients who would not benefit from treatment. In recent decades, the study of RAS has expanded and evolved rapidly. In this review, we will attempt to summarize the amassed body of literature with a focus on the epidemiology of RAS including prevalence, overlap with other atherosclerotic disease, and prognosis. We will also outline existing diagnostic and treatment approaches available to clinicians as well as summarize the findings of several major clinical trials. Finally, we will offer our perspective on future directions in the field.

Nonenhanced arterial spin labeled carotid MR angiography using three-dimensional radial balanced steady-state free precession imaging

PURPOSE

To optimize and preliminarily evaluate a three-dimensional (3D) radial balanced steady-state free precession (bSSFP) arterial spin labeled (ASL) sequence for nonenhanced MR angiography (MRA) of the extracranial carotid arteries.

MATERIALS AND METHODS

The carotid arteries of 13 healthy subjects and 2 patients were imaged on a 1.5 Tesla MRI system using an undersampled 3D radial bSSFP sequence providing a scan time of ∼4 min and 1 mm(3) isotropic resolution. A hybridized scheme that combined pseudocontinuous and pulsed ASL was used to maximize arterial coverage. The impact of a post label delay period, the sequence repetition time, and radiofrequency (RF) energy configuration of pseudocontinuous labeling on the display of the carotid arteries was assessed with contrast-to-noise ratio (CNR) measurements. Faster, higher undersampled 2 and 1 min scans were tested.

RESULTS

Using hybridized ASL MRA and a 3D radial bSSFP trajectory, arterial CNR was maximized with a post label delay of 0.2 s, repetition times ≥ 2.5 s (P < 0.05), and by eliminating RF energy during the pseudocontinuous control phase (P < 0.001). With higher levels of undersampling, the carotid arteries were displayed in ≤ 2 min.

CONCLUSION

Nonenhanced MRA using hybridized ASL with a 3D radial bSSFP trajectory can display long lengths of the carotid arteries with 1 mm(3) isotropic resolution.

Diagnosis and treatment of glomerular diseases in elderly patients

Glomerular diseases are common in elderly patients and are a major cause of kidney failure. Most glomerular diseases in the elderly are caused by chronic systemic diseases, including arterial hypertension, diabetes, and atherosclerotic vascular diseases, although acute systemic vasculitis, especially anti-neutrophil-cytoplamic-antibody-mediated vasculitis, and membranous nephropathy related to malignancy, drug toxicity, and idiopathic form also occur often. Complex age-related changes and sensitivity to drug toxicity can render diagnosis and treatment for elderly patients challenging. As the general population is aging and the rate of CKD rising, updating knowledge on managing these patients is critical for care providers. We provide a comprehensive review and update of the diagnosis and treatment of glomerular diseases in the elderly.

Successful percutaneous transluminal angioplasty for the treatment of renovascular hypertension with an atrophic kidney

Renovascular hypertension is an important cause of secondary hypertension. We present the case of a 61-year-old man with renovascular hypertension caused by chronic total occlusion of the left renal artery resulting in an atrophic kidney. Although renography indicated almost no residual function of the left kidney, renal vein sampling showed a significant increase of renin secretion in the left kidney. The endocrine function of the left kidney was believed to be preserved; thus, we performed percutaneous transluminal renal angioplasty with stent placement. After the procedure, the patient’s blood pressure decreased gradually to within the normal range without adverse events. The laboratory data on endocrine function and the renography findings drastically improved. Percutaneous transluminal renal angioplasty is a promising therapeutic procedure for renovascular hypertension with an atrophic kidney.

Diagnosis and therapy of atheromatous renal artery stenosis

Atheromatous renal artery stenosis (ARAS), a lesion of systemic atherosclerotic disease, is the leading cause of stenotic lesions in the renal artery, followed by fibromuscular dysplasia, a primary abnormality of the renal artery. As a result of several clinical trails, which failed to show an additional benefit of renal revascularization to medical therapy in ARAS, the treatment of ARAS has shifted, and renal revascularization is less commonly performed for ARAS. However, it is recognized that renal revascularization benefits some patients with ARAS. Advances in imaging modalities would allow more frequent detection of ARAS in a society with a growing elderly population, a group with an increased prevalence of systemic atherosclerotic disease. Therefore, it is imperative to identify the patients with ARAS who could benefit from renal revascularization. This review presents a strategy for the treatment of ARAS based on the results of our analysis.

Renal artery stenosis predicts coronary artery disease in patients with hypertension

In hypertensive patients with indication of renal arteriography to investigate renal artery stenosis (RAS) there are no recommendations regarding when to investigate coronary artery disease (CAD). Moreover, the predictors of CAD in patients with RAS are not clear. We aimed to evaluate the frequency and the determinants of CAD in hypertensive patients referred to renal angiography. Eighty-two consecutive patients with high clinical risk suggesting the presence of RAS systematically underwent renal angiography and coronary angiography during the same procedure. Significant arterial stenosis was defined by an obstruction ≥ 70% to both renal and coronary territories. Significant CAD was present in 32/82 (39%) and significant RAS in 32/82 (39%) patients. Both CAD and RAS were present in 25.6% from the 82 patients. Patients with severe CAD were older (63 ± 12 vs. 56 ± 13 years; p = 0.03) and had more angina (41 vs. 16%; p = 0.013) compared to patients without severe CAD. Significant RAS was associated with an increased frequency of severe CAD compared to patients without significant RAS (66% vs. 22%, respectively; p<0.001). Myocardial scintigraphy showed ischemia in 21.8% of the patients with CAD. Binary logistic regression analysis showed that RAS ≥ 70% was independently associated with CAD ≥ 70% (OR: 11.48; 95% CI 3.2-40.2; p<0.001), even in patients without angina (OR: 13.48; 95%CI 2.6-12.1; p<0.001). Even considering a small number of patients with significant RAS, we conclude that in hypertensive patients referred to renal angiography, RAS ≥ 70% may be a strong predictor of severe CAD, independently of angina, and dual investigation should be considered.

Stroke and renal dysfunction: are we always conscious of this relationship?

Cerebrovascular disease may represent an important clinical presentation of atherosclerosis in chronic kidney disease (CKD), and atherosclerosis is frequently encountered in CKD. In fact, kidney disease is now considered a risk factor for development of cardiovascular disease. Although guidelines for primary prevention of stroke have been recently published, CKD is hardly mentioned. Based on a series of available studies, we analyzed the relationship between reduced renal function, end-stage renal disease (ESRD), and stroke. Reduced renal function and risk of stroke appear to be related to the highest risk of patients on dialysis treatment. Primary and secondary prevention of stroke should be encouraged in participants with renal dysfunction.

Secondary arterial hypertension: improvements in diagnosis and management in the last 10 years

The diagnosis and management of secondary hypertension has improved in the last decade as a result of the advances in the acknowledgment of some physiopathologic mechanisms and mainly by the development of new diagnostic methods. Furthermore, the treatment of some types of secondary hypertension may be solved by noninvasive techniques. Hypertension of renal and renovascular origin, coarctation of the aorta, primary hyperaldosteronism, and adrenal medullary tumors are analyzed. The main results of some relevant studies on diagnostic and treatment of those diseases are presented. Also, some experimental methods are mentioned, taking into account the possibility of clinical use in the near future.

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.

Atherosclerotic renovascular disease and the heart

The detrimental link between cardiac and renal pathophysiology in atherosclerotic renovascular disease (ARVD) is well described. Patients with ARVD usually have significant atherosclerotic disease in other vascular beds including the coronary circulation, and structural and functional cardiac changes are highly prevalent. This excess cardiovascular burden probably contributes to the increased cardiac morbidity and mortality seen in these patients. In this review we describe the associations of cardiovascular disease and ARVD and treatment thereof. The clinical debate of which patients are offered any additional advantage by revascularisation over medications alone remains to be answered. The close link between cardiac and renal pathophysiology in ARVD raises the possibility that renal revascularisation might confer a benefit to cardiac morphology and function. This is the subject of ongoing randomised controlled trials.

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.

“Does chronic kidney disease define a particular risk pattern of cerebral vessels modifications in patients with symptomatic ischemic cerebrovascular disease?”

Cardiovascular complications, including stroke, may be attributed the highest rate of morbidity and mortality in patients with chronic kidney disease (CKD). The aim of our study was to evaluate the prevalence of CKD in patients with symptomatic ischaemic cerebrovascular disease and to establish of whether CKD may define a particular risk pattern of cerebral vessels modifications in this category of patients. The prevalence of CKD was evaluated in 590 consecutive patients with symptomatic ischaemic cerebrovascular disease admitted to a department of neurology. The types of stroke, the vascular territories, the vascular modifications and the haemodynamic changes (resistance index- RI) found by neurosonology (extracranial and transcranial Doppler ultrasound) were analysed in relation to classic and non-classic cerebrovascular risk factors, as well as to stages of CKD (defined by estimated glomerular filtration rate-eGFR-MDRD4 formula-K/DOQI 2002). The prevalence of CKD in the studied patients was 70.84%. Atherosclerosis in a diffuse pattern was detected in 79.7% of CKD patients, while carotid artery stenoses were found in 10% of cases, occlusions- 5.3%, stenoses + occlusions-1.2%, and multiple stenoses- 3.8% of cases. The RI evaluated in the internal carotid arteries correlated with fibrinogen(P<0.0001) and GFR(P<0.0001), while IR in the middle cerebral arteries correlated with fibrinogen(P<0.05), C-reactive protein(P<0.0001), and GFR(P<0.0001). There is a strong relation between symptomatic cerebrovascular disease and CKD, a fact demonstrated by the increased prevalence of CKD in these patients and by the severity of the cerebral vessels lesions.

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.

Coronary calcification in patients with chronic kidney disease and coronary artery disease

BACKGROUND AND OBJECTIVES

A close linkage between chronic kidney disease (CKD) and cardiovascular disease (CVD) has been demonstrated. Coronary artery calcification (CAC) is considered to be the causal link connecting them. The aim of the study is to determine the relationship between level of kidney function and the prevalence of CAC.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Autopsy subjects known to have coronary artery disease and a wide range of kidney function were studied. Patients without CKD were classified into five groups depending on estimated GFR (eGFR) and proteinuria: eGFR > or =60 ml/min/1.73 m(2) without proteinuria; CKD1/2: eGFR > or =60 ml/min/1.73 m(2) with proteinuria; CKD3: 60 ml/min/1.73 m(2) >eGFR > or =30 ml/min/1.73 m(2); CKD4/5: eGFR <30 ml/min/1.73 m(2); and CKD5D: on hemodialysis. Intimal and medial calcification of the coronary arteries was evaluated. Risk factors for CVD and uremia were identified as relevant to CAC using logistic regression analysis.

RESULTS

Intimal calcification of plaques was present in all groups, but was most frequent and severe in the CKD5D group and less so in the CKD4/5 and CKD3 groups. Risk factors included luminal stenosis, age, smoking, diabetes, calcium-phosphorus product, inflammation, and kidney function. Medial calcification was seen in a small number of CKD4/5 and CKD5D groups. Risk factors were use of calcium-containing phosphate binders, hemodialysis treatment, and duration.

CONCLUSIONS

It was concluded that CAC was present in the intimal plaque of both nonrenal and renal patients. Renal function and traditional risks were linked to initimal calcification. Medial calcification occurred only in CKD patients.

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.

Renal dysfunction in acute stroke: an independent predictor of long-term all combined vascular events and overall mortality

BACKGROUND

Acute stroke is the third leading cause of death in western societies after ischemic heart disease and cancer. Although it is an emergency disease sharing the same atherosclerotic risk factors with ischemic heart disease, the association of renal function and stroke is poorly investigated. The present study aims at assessing renal function status in patients with acute stroke and investigate any prognostic significance on the outcome.

METHODS

This is a prospective study of hospitalized first-ever stroke patients over 10 years. The study population comprised 1350 patients admitted within 24 h from stroke onset and followed up for 1 to 120 months or until death. Patients were divided in 3 groups on the basis of the estimated Glomerular Filtration Rate (eGFR) that was calculated from the abbreviated equation of the Modification Diet for Renal Disease in ml/min/1.73 m(2) of body surface area: Group-A comprised patients who had eGFR > 60, group-B those with 30 <or= eGFR <or= 60 and group-C patients with eGFR < 30. Patients with Acute Kidney Injury (AKI) were excluded from the study. The main outcome measures were overall mortality and the composite new cardiovascular events (myocardial infarction, recurrent stroke, vascular death) among the 3 groups during the follow-up period.

RESULTS

Almost 1/3 (28.08%) of our acute stroke patients presented with moderate (group B) or severe (group C) renal dysfunction as estimated by eGFR. After adjusting for basic demographic, stroke risk factors and stroke severity on admission, eGFR was an independent predictor of stroke mortality at 10 years. Patients in groups B and C had an increased probability of death during follow-up: Hazard ratio = 1.21 with 95% CI 1.01-1.46, p < 0.05 and Hazard ratio = 1.76 with 95% CI 1.14-2.73, p < 0.05 respectively, compared to patients belonging to group A. The probability of death from any cause was significantly different among groups (log rank test 55.4, p = 0.001) during the follow-up period: in group-A patients it was 62.8 (95% CI 57.6-68.1), in group-B 77.3 (95% CI 68.5-86.1) and in group-C 89.2 (95% CI 75.1-100). During the follow-up period 336 new cardiovascular events occurred. The probability to have a new composite cardiovascular event was also significantly different among the 3 groups (log rank test 21.1, p = 0.001): in group-A patients it was 45.2 (95% CI 38.7-51.7), in group-B 67.4 (95% CI 56.2-78.6) and in group-C 77.6 (95% CI 53.5-100).

CONCLUSION

Renal function on admission appears to be a significant independent prognostic factor for long term mortality and new cardiovascular morbidity over a 10-year period.

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.

Renal artery calcium: relationship to systemic calcified atherosclerosis

In this study we tested the hypothesis that calcium due to atherosclerosis in the renal arteries would be significantly associated with calcium in multiple other vascular beds, independent of traditional risk factors for cardiovascular disease (CVD). Electron beam computed tomography was conducted in 1461 consecutive asymptomatic patients free of clinical CVD to determine the presence and extent of calcium in the renal arteries, coronary and non-coronary vasculature and the aortic and mitral annuli. The overall prevalence for calcium in either renal artery was 18.0%, with men having a significantly higher prevalence (20.2%) than women (15.0%) [p = 0.01]. Renal artery calcium (RAC) was significantly correlated with calcium located in the carotids, coronaries, thoracic aorta, abdominal aorta and iliac arteries and calcium in the mitral and aortic annuli (r range = 0.22-0.37). In a multi-variable model containing the traditional CVD risk factors, the presence of calcium in the renal arteries was significantly associated with age, male sex and a diagnosis of hypertension. After adjustment for these variables, the presence of calcium in the thoracic or abdominal aorta was significantly associated with RAC (OR = 2.1 and 2.0, respectively; p < 0.01 for both). The sensitivity for prevalent RAC was highest in those individuals with any calcium in the abdominal aorta (94.5%). In conclusion, calcium related to atherosclerosis in the renal arteries is highly associated with atherosclerotic calcification in other vascular beds, especially the aorta, and the valvular annuli. These relationships are independent of traditional CVD risk factors.

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.

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.

The heart in renovascular disease—An association demanding further investigation

A close relationship exists between cardiovascular and renal disease; they often occur concomitantly, and abnormalities in either system are pathophysiologically important in both causing disease and determining clinical outcome in the other. Whilst the main focus of the article relates to the adverse association between atherosclerotic renovascular disease (ARVD) and the cardiovascular system, it is important to briefly review relevant epidemiology.

Atherosclerotic renovascular disease

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

Atherosclerotic renal artery stenosis and renovascular hypertension: clinical diagnosis and indications for revascularization

Atherosclerotic renal artery stenosis (RAS) is relatively common and often associated with reversible hypertension, progressive renal insufficiency, and/or coronary-independent pulmonary edema. Not all RAS is associated with renovascular hypertension. Historical and physical findings may suggest renovascular hypertension and warrant investigation for RAS. Noninvasive diagnostic imaging options include renal artery duplex ultrasonography, magnetic resonance angiography, computed tomographic angiography, and CO2 angiography, with each method having its own advantages and limitations. Functional tests of renal flow, which characterize RAS significance, include captopril-stimulated plasma renin activity and captopril renography. To date, no single approach has shown clear superiority either in diagnosis or identification of patients most likely to benefit from revascularization. Revascularization of RAS is recommended for severe/drug-refractory hypertension, preservation of renal function, recurrent flash pulmonary edema, or recurrent severe heart failure. Intervention response is variable, but the ongoing Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial, comparing medical therapy with and without stenting, should provide management guidance.

Coronary bypass procedures in patients with renal artery stenosis

BACKGROUND AND AIM OF THE STUDY

We present our experience on patients with renal artery stenosis undergoing myocardial revascularization procedures.

METHODS

Eighteen patients with varying degrees of renal artery stenosis were operated for coronary artery bypass grafting between 1996 and 2003. The overall incidence was 0.15%. There were nine male and nine female patients with a mean age of 62 +/- 8.2 (40-72 years). Four had bilateral and eight had significant unilateral (>50%) renal artery stenoses. Preoperatively, three patients had renal arterial intervention (stenting), and one patient was on hemodialysis. The mean preoperative creatinine value was 2.6 +/- 2.7 mg/dL (range 0.7 to 9.3). The patients were followed medically: two patients underwent off-pump coronary bypass grafting and the others were operated on-pump.

RESULTS

There was only one mortality and two patients required hemodialysis postoperatively. The postoperative mean creatinine values were 3.4 +/- 4.9 mg/dL (range 1.0 to 12.5). No electrolyte imbalances were noted except that one case revealed a transient metabolic acidosis. Five patients required inotropic support with dopamine and two needed diuretic infusions. Only five patients demonstrated a refractory hyper tensive period postoperatively.

CONCLUSIONS

The concomitant correction of renal artery stenosis with CABG is usually not necessary, but the principles for renovascular diseases must be kept in mind and individually oriented strategies must be planned.