Atherosclerotic ischemic renal disease

Evaluations of secondary hypertension and laboratory data in the elderly population

Secondary hypertension in the elderly poses many challenges and requires a comprehensive diagnostic and management approach. This review explores the prevalence, diagnostic strategies, and treatment modalities for secondary hypertension in elderly patients, focusing on etiologies including primary aldosteronism, renal vascular disease, renal parenchymal disease, obstructive sleep apnea, thyroid disorders, Cushing's syndrome, pheochromocytomas and paragangliomas, and drug-induced hypertension. Key considerations include age-related changes in physiology and atypical presentations of underlying conditions necessitating thorough screening with a combination of clinical evaluation, laboratory tests, and imaging studies. Collaboration among healthcare providers is essential to ensure a timely diagnosis and personalized management tailored to the unique needs of elderly patients. Further research is needed to address knowledge gaps and optimize clinical strategies for managing secondary hypertension in this population.

Reversible Ischemic Nephropathy in a Deceased Donor Renal Transplant Recipient With BK Nephropathy

Atherosclerotic renal artery stenosis is one of the risk factors for cardiovascular death and can lead to the ischemic nephropathy. In this report, we describe the successful management of ischemic nephropathy that developed in a kidney transplant recipient with graft artery stenosis. The 52-year-old male patient had diabetes and hypertension and was a nonsmoker with hypothyroidism on replacement therapy. He had a history of recurrent urinary tract infection due to vesicoureteric reflux before starting hemodialysis in July 2009. In November 2020, he received a deceased donor renal allograft and showed slow graft function. He received thymoglobulin as induction and steroid, tacrolimus, and mycophenolate mofetil as maintenance therapy. He was discharged with nadir creatinine around 130 μmol/L. His diabetes was controlled by intensive insulin regimen. Later, he presented with graft dysfunction with partially controlled hypertension and suspected graft artery stenosis by Doppler ultrasonography but no evidence of obstruction. His tacrolimus level was adequate, and his echocardiography was unremarkable. He received empirical pulse steroid. A graft biopsy showed severe acute tubular necrosis, suspicious T-cell-mediated rejection, and negative C4d and positive SV40 stain, suggesting BK nephropathy. His BK viremia (500 copies/mL) and viruria (885 billion copies/mL) improved after immunosuppression minimization, although he remained dependent on dialysis. A repeated Doppler ultrasonogram showed flattening of the systolic wave. Computed tomographic angiography revealed diffusely attenuated graft arteries. The patient received graft artery angioplasty and stenting of the 2 arteries. The patient showed good response, with same-day urine production and Doppler showing good systolic wave. His graft function started to improve, and he was discharged with stable graft function. His immunosuppressive regimen was subsequently tailored to steroid and low-dose tacrolimus. In conclusion, we found that ischemic nephropathy could be reversed if properly managed, even in presence of other comorbidities.

Cell-based regenerative medicine for renovascular disease

Renal artery stenosis (RAS) elicits the development of hypertension and post-stenotic kidney damage, which may become irresponsive to restoration of arterial patency. Rather than mere losses of blood flow or oxygen supply, irreversible intrarenal microvascular rarefaction, tubular injury, and interstitial fibrosis are now attributed to intrinsic pathways activated within the kidney, focusing attention on the kidney parenchyma as a therapeutic target. Several regenerative approaches involving the delivery of reparative cells or products have achieved kidney repair in experimental models of RAS and the delivery of mesenchymal stem/stromal cells (MSCs) has already been translated to human subjects with RAS with promising results. The ongoing development of innovative approaches in kidney disease awaits application, validation, and acceptance as routine clinical treatment to avert kidney damage in RAS.

Association between urinary biomarkers and disease progression in adults with autosomal dominant polycystic kidney disease

Background

Height-adjusted total kidney volume (htTKV) is considered as the best predictor of kidney function in patients with autosomal dominant polycystic kidney disease (ADPKD), but its limited predictive capacity stresses the need to find new biomarkers of ADPKD progression. The aim of this study was to investigate urinary biomarkers of ADPKD progression.

Methods

This observational study included ADPKD patients, and two comparator groups of ischaemic and non-ischaemic kidney injury: benign nephroangiosclerosis patients and non-ischaemic chronic kidney disease (CKD) patients. Proteinuria, htTKV and urinary levels of molecules are associated with ischaemia and/or tubular injury. The slope of estimated glomerular filtration rate (eGFR) was used as a dependent variable in univariate and multivariate models of kidney function decline.

Results

The study included 130 patients with ADPKD, 55 with nephroangiosclerosis and 40 with non-ischaemic CKD. All patients had increased urinary concentrations of biomarkers associated with tubular lesions (liver fatty acid-binding protein, kidney injury molecule-1, β2-microglobulin) and molecules overexpressed under ischaemic conditions [hypoxia-inducible factor-1α, vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein-1 (MCP-1)]. These biomarkers correlated positively with htTKV and negatively with the eGFR slope. htTKV was the single best predictor of the eGFR slope variability in univariate analyses. However, a multivariate model including urinary levels of β2-microglobulin, MCP-1 and VEGF improved the capacity to predict the decline of eGFR in ADPKD patients compared with htTKV alone.

Conclusions

The urinary levels of molecules associated with either renal ischaemia (VEGF and MCP-1) or tubular damage (β2-microglobulin) are associated with renal function deterioration in ADPKD patients, and are, therefore, candidates as biomarkers of ADPKD progression.

[Kidney disease care for the elderly]

In our aging population, kidney disease management needs to take into account the frailty of the elderly. Standardized geriatric assessments can be proposed to help clinicians apprehend this dimension in their daily practice. These tools allow to better identify frail patients and offer them more personalized and harmless treatments. This article aims to focus on the kidney diseases commonly observed in elderly patients and analyze their specific nephrogeriatric care modalities. It should be noticed that all known kidney diseases can be also observed in the elderly, most often with a quite similar clinical presentation. This review is thus focused on the diseases most frequently and most specifically observed in elderly patients (except for monoclonal gammopathy associated nephropathies, out of the scope of this work), as well as the peculiarities of old age nephrological care.

[Doppler ultrasonography of the renal artery: Guidelines and predictive factors for the presence of a tight stenosis. Retrospective analysis of 450 consecutive examinations]

Duplex ultrasonography screening for renal artery stenosis has been the object of guidelines published by four societies designed to optimize the cost-effectiveness of the examination.

OBJECTIVES

To determine how well guideline indications for ultrasonography matched with requests and results in our university hospital; to determine whether compliance with guidelines was predictive of renal artery stenosis; to identify guidelines predictive of presence of stenosis; and to determine whether other predictive factors can be recognized.

MATERIAL AND METHODS

Requests and results of 450 Duplex ultrasonography examinations of the renal arteries performed from January 1st 2014 to December 31st 2015 were compared with published guidelines.

RESULTS

At least one guideline indication was identified for 212 of the 450 examinations performed (47.1%). Among these examinations, renal artery stenosis≥70% was identified in 18 patients (8.0%). No case of stenosis was identified during examinations performed outside guideline indications. Factors predictive of stenosis were: compliance with guidelines (OR=21.86 [2.88; 165.8]). Predictive guidelines were: resistant hypertension in spite of appropriate treatment (OR=3.85, [1.44; 10.33], P=0.011), accelerated hypertension (OR=7.30, [1.40; 37.99], P=0.049), sudden unexplained pulmonary edema (OR=7.30, [1.40; 37.99], P=0.049), unexplained renal insufficiency (OR=3.58, [1.37; 9.37], P=0.011), unexplained renal hypotrophy (OR=16.69, [4.38; 63.69], P<0.001), renal asymmetry (OR=4.32, [1.45; 12.85], P<0.016). No other factor was predictive of renal stenosis. These examinations had therapeutic consequences in only 50% of patients.

CONCLUSION

This study confirms the relevance of published guidelines. The diagnostic-effectiveness of Duplex ultrasonography examinations to search for renal artery stenosis depends upon compliance with these guidelines.

MicroRNA profiling in kidney disease: Plasma versus plasma-derived exosomes

Liquid biopsies have advanced rapidly in recent years for use in diagnostic and prognostic applications. One important aspect of this advancement is the growth in our understanding of microRNA (miRNA) biology. The measurement of miRNAs packaged within exosomes, which are constantly released into the blood stream, may reflect pathological changes within the body. The current study performed miRNA profiling using plasma and plasma-derived exosome samples from two animal models of kidney disease, the 5/6th partial nephrectomy (PNx) and two-kidney-one-clip (2K1C) models. The RT-qPCR-based profiling results revealed that the overall miRNA expression level was much higher in plasma than in plasma-derived exosomes. With 200μl of either plasma or exosomes derived from the same volume of plasma, 629 out of 665 total miRNAs analyzed were detectable in plasma samples from sham-operated rats, while only 403 were detectable in exosomes with a cutoff value set at 35cycles. Moreover, the average miRNA expression level in plasma was about 16-fold higher than that in exosomes. We also found a select subset of miRNAs that were enriched within exosomes. The number of detectable miRNAs from plasma-derived exosomes was increased in rats subjected to PNx or 2K1C surgery compared to sham-operated animals. Importantly, we found that the changes of individual miRNAs measured in plasma had very poor concordance with that measured in plasma-derived exosomes in both animal models, suggesting that miRNAs in plasma and plasma-derived exosomes are differentially regulated in these disease conditions. Interestingly, PNx and 2K1C surgeries induced similar changes in miRNA expression, implying that common pathways were activated in these two disease models. Pathway analyses using DIANA-miRPath v3.0 showed that significantly changed exosomal miRNAs were associated with extracellular matrix (ECM) receptor interaction and mucin type-O-glycan synthesis pathways, which are related with tissue fibrosis and kidney injury, respectively. In conclusion, our results demonstrated that due to the differential changes in miRNAs, the measurement of exosomal miRNAs cannot be replaced by the measurement of miRNAs in plasma, or vice versa. We also showed that a set of miRNAs related with kidney injury and organ fibrosis were dysregulated in plasma-derived exosomes from animal models of kidney disease.

Endovascular versus medical therapy for atherosclerotic renovascular disease

The diagnosis of renal artery stenosis (RAS) has become increasingly common in part due to greater awareness of ischemic renal disease and increased use of diagnostic techniques. Over 90 % of RAS cases are caused by atherosclerotic renovascular disease (ARVD). Patients with ARVD are at high risk for fatal and nonfatal cardiovascular and renal events. The mortality rate in patients with ARVD is high, especially with other cardiovascular or renal comorbidities. Recent clinical studies have provided substantial evidence concerning medical therapy and endovascular interventional therapeutic approaches for ARVD. Despite previous randomized clinical trials, the optimal therapy for ARVD remained uncertain until the results of the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial were released recently. CORAL demonstrated that optimal medical therapy was equally effective to endovascular therapy in the treatment of ARVD. Clinicians can now practice with more evidence-based medicine to treat ARVD and potentially decrease mortality in patients with ARVD using optimal medical therapy.

Cardiorenal syndrome: pathophysiology and potential targets for clinical management

Combined dysfunction of the heart and the kidneys, which can be associated with haemodynamic impairment, is classically referred to as cardiorenal syndrome (CRS). Cardiac pump failure with resulting volume retention by the kidneys, once thought to be the major pathophysiologic mechanism of CRS, is now considered to be only a part of a much more complicated phenomenon. Multiple body systems may contribute to the development of this pathologic constellation in an interconnected network of events. These events include heart failure (systolic or diastolic), atherosclerosis and endothelial cell dysfunction, uraemia and kidney failure, neurohormonal dysregulation, anaemia and iron disorders, mineral metabolic derangements including fibroblast growth factor 23, phosphorus and vitamin D disorders, and inflammatory pathways that may lead to malnutrition-inflammation-cachexia complex and protein-energy wasting. Hence, a pathophysiologically and clinically relevant classification of CRS based on the above components would be prudent. With the existing medical knowledge, it is almost impossible to identify where the process has started in any given patient. Rather, the events involved are closely interrelated, so that once the process starts at a particular point, other pathways of the network are potentially activated. Current therapies for CRS as well as ongoing studies are mostly focused on haemodynamic adjustments. The timely targeting of different components of this complex network, which may eventually lead to haemodynamic and vascular compromise and cause refractoriness to conventional treatments, seems necessary. Future studies should focus on interventions targeting these components.

Nefropatia isquêmica

A doença renal isquêmica ou nefropatia isquêmica relacionada à doença renovascular pode evoluir de forma rápida e progressiva para a insuficiência renal crônica. É fundamental a identificação e o tratamento precoces desta condição clínica, prevenindo a ocorrência de doença renal em estágio terminal, com consequente necessidade de terapia de substituição renal. Há uma década, o controle da hipertensão renovascular era o objetivo primário no manejo de pacientes com doença renovascular. Atualmente, a meta está dirigida principalmente para a estabilização e a melhora da função renal, além do controle dos níveis pressóricos.

Serum antibody to Porphyromonas gingivalis in chronic kidney disease

Potentially significant associations between periodontal disease and chronic kidney disease (CKD) have been reported in recent studies. The aim of this cross-sectional study was to investigate the association between serum antibody to the periodontal pathogen Porphyromonas gingivalis (P. gingivalis) and CKD in 215 Japanese individuals, aged 79 yrs. Serum antibody levels to P. gingivalis were measured by enzyme-linked immunosorbent assay. An elevated serum antibody response was defined as the upper quartile and was compared with the bottom three quartiles. Participants were classified as having CKD when their glomerular filtration rate was between 15 and 59 mL/min/1.73 m(2). A multivariable logistic regression model was used to evaluate the association between elevated antibody status and the presence of CKD. Study participants with an elevated serum antibody to P. gingivalis were 2.6 times more likely to have CKD. The adjusted odds ratio of CKD for participants in the highest quartile of serum antibody to P. gingivalis was 2.59 (95% confidence interval, 1.05-6.34) when compared with others in lower quartiles after simultaneous adjustment for other covariates. In conclusion, the present study suggests that elevated serum antibody to P. gingivalis was significantly associated with decreased kidney function in a community-based cohort of elderly Japanese.

[Role of angioplasty in the treatment of renal artery stenosis]

Atherosclerotic renal artery stenosis is frequent and is associated with a high incidence of morbidity and mortality, with a strong correlation with coronary artery disease, (Kalra et al., 2005; Cheung et al., 2002; Guo et al., 2007 [1-3]). The atherosclerotic renal artery stenosis is an independent predictive factor of death (Conlon et al., 1998 [4]). The treatment of this lesion does not have strong evidence. A lot of studies in this area suggest the angioplasty is superior in a big majority between surgery, and angioplasty with stent is superior between balloon angioplasty, but some studies fail to prove the superiority of angioplasty versus medical treatment. These studies have sadly a lot of mistakes and nowadays we don't know what is the treatment for our patients in a lot of cases. The angioplasty is indicated when there is a failure of antihypertensive medications for control of blood pressure, when it is associated with a renal insufficiency quickly progressive or when there is a lesion on each renal artery. Other studies must be organized for prove the superiority of angioplasty when there is a real stenosis, maybe with the use of fractional flow reserve.

Geriatric nephrology: responding to a growing challenge

Changing demographics of the global population predict that the number of people age 65 years or greater will triple over the coming decades. Because the incidence and prevalence of kidney disease increase with advancing age, nephrologists will be increasingly confronted with a population of patients who are elderly and have a large number of comorbid conditions requiring ongoing care. Furthermore, it is increasingly understood that aging leads to its own unique aspects of nephrologic diagnosis and treatment. Although it is known that elderly patients constitute a group with special needs and present unique challenges to the nephrologist, traditional nephrology fellowship training has not included a focus on the geriatric population. In response to this need for greater education and awareness, the American Society of Nephrology has initiated a program of educational activities in geriatric nephrology and has chartered a specific advisory council. The priority being given to geriatric nephrology is a hopeful sign that issues such as treatment options, the efficacy of treatments, and their effect on quality of life for the elderly patient with kidney disease will be improved in the coming years.

Mechanisms of tissue injury in renal artery stenosis: ischemia and beyond

Renal injury distal to an atherosclerotic renovascular obstruction reflects multiple intrinsic factors producing parenchymal tissue injury. Atherosclerotic disease pathways superimposed on renal arterial obstruction may aggravate damage to the kidney and other target organs, and some of the factors activated by renal artery stenosis may in turn accelerate the progression of atherosclerosis. This cross-talk is mediated through amplified activation of renin-angiotensin system, oxidative stress, inflammation, and fibrosis-pathways notoriously involved in renal disease progression. Oxidation of lipids also accelerates the development of fibrosis in the stenotic kidney by amplifying profibrotic mechanisms and disrupting tissue remodeling. The extent to which actual ischemia modulates injury in the stenotic kidney has been controversial, partly because the decrease in renal oxygen consumption usually parallels a decrease in renal blood flow, and because renal vein oxygen pressure in the affected kidney is not decreased. However, recent data using novel methodologies demonstrate that intra-renal oxygenation is heterogeneously affected in different regions of the kidney. Activation of such local injury within the kidney may lead to renal dysfunction and structural injury, and ultimately unfavorable and irreversible renal outcomes. Identification of specific pathways producing progressive renal injury may enable development of targeted interventions to block these pathways and preserve the stenotic kidney.

A Longitudinal Study of the Yield and Clinical Utility of a Specifically Designed Secondary Hypertension Investigation Protocol

OBJECTIVE

It has become common practice to use a day-case based approach to identify from the population of hypertensive patients those with an identifiable cause. We aimed to prospectively identify 96 consecutive hypertensive patients undergoing an algorithmic investigation protocol based around two day case hospital attendances.

METHODS

The overall diagnostic yield and associated costs were recorded and the patients were observed for a mean of 2.5 years with ambulatory blood pressure (BP) monitoring every three months.

RESULTS

A secondary cause of hypertension was identified in 18.1% of patients, three quarters of whom had renovascular disease. There was a fall in blood pressure with time (157/97 vs. 140/85) but this was associated with an increase in the amount of medication required (mean medication score 5.99 vs. 7.65). Improvement in BP occurred irrespective of whether or not a secondary cause was identified. Only 3.2% of patients were cured of their hypertension as a result of enrollment in the protocol. The cost of identifying each case of secondary hypertension was Euro 10, 196.

CONCLUSIONS

A comprehensive protocol aimed at identifying secondary hypertension had a low yield, the majority of whom had renovascular disease. In light of recent data illustrating the lack of improvement in BP following dilatation or bypass of atherosclerotic renovascular disease, it is debatable whether searching for it is justifiable.

[Atherosclerotic renal artery disease diagnosis update]

Atherosclerotic renal artery disease represents a cause of which little is known but not a cause to be neglected for hypertension and renal insufficiency. Even though its occurrence remains badly defined, atherosclerotic renal artery disease is constantly on the rise due to the aging population, the never prevailing hypertension and diabetes mellitus. This review aims to give a clinical profile of patients presenting with atherosclerotic renal artery disease and to discuss, in the light of study results, which diagnostic evaluation should be used considering the sequence and the benefit and risk of each in order to initiate a personalized treatment. Patients affected by atherosclerotic renal artery disease are likely to have more complications and more extensive target-organ damage than patients without renal artery stenosis. The evolution of the atherosclerotic renal artery disease is in general slow and progressive. Nevertheless, certain clinical cases manifest themselves with the onset of acute renal failure bought upon by the administration of blockers of the rennin-angiotensin-aldosterone system, or by some other causes responsible for a sudden drop in renal plasma flow (e.g., thrombosis of the renal artery). The relationship between atherosclerotic renal artery disease and atherosclerosis is complex, and mediators implicated in the pathophysiology of renovascular disease may also contribute to the progression of cardiovascular damage. An early assumption of the atherosclerotic renal artery stenosis is warranted to determine the adapted treatment (i.e., medical treatment, revascularisation...) just as the assumption and the correction of the more general cardiovascular risk factors.

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.

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.

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.

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.

Early detection of progressive renal dysfunction in patients with coronary artery disease

BACKGROUND

An association between renal hemodynamic dysfunction and coronary artery disease (CAD) has been documented in chronic renal failure; however, no information is available in CAD patients with normal glomerular filtration rate (GFR). This study was aimed at evaluating early abnormalities and outcome of renal function in CAD patients.

METHODS

In 15 nondiabetic patients with normal renal function and no significant stenoses in renal arteries, and having undergone coronary arteriography, we studied systemic and renal hemodynamics before and after a vasodilating stimulus induced by aminoacid (AA) infusion. A control group (C) consisted of 15 sex- and age-matched kidney donors. The statistical adequacy of the sample size was preliminarily verified. Renal clearances were repeated after two years.

RESULTS

At baseline, GFR (mL/min/1.73 m2) averaged 81.4 +/- 3.8 in CAD and 83.7 +/- 1.4 in C (P= NS); RPF (mL/min/1.73 m2) was 297 +/- 22 in CAD and 456 +/- 15 in C (P < 0.0001); filtration fraction was higher in CAD (P < 0.001). Plasma renin activity was higher in CAD (P < 0.005). The number of coronary stenoses was inversely correlated with RPF but not with GFR. In CAD, at variance with C, AA did not induce any increment of GFR, while RPF increased without achieving the unstimulated value of C. Blood pressure was comparable in CAD and C at baseline and not modified by AA. After two years, a significant decrease in GFR (-14%, P < 0.001) and RPF (-15%, P < 0.001) occurred only in CAD, and in either group, the response to AA did not differ from that detected at baseline.

CONCLUSION

In CAD patients with normal GFR, reduction in renal perfusion and absence of renal functional reserve likely represent early markers of progressive renal dysfunction.

Renal artery stenosis in patients with peripheral vascular disease in Kuwait

OBJECTIVE

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

SUBJECTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Atherosclerosis and the kidney]

Diffuse atherosclerosis entails a 15-30% risk of plaques on renal arteries (ARAS), with a correlation with coronary atherosclerosis. Ischemia induces generation of angiotensin II (Ang II) that maintains sufficient hydrostatic pressure within the tuft to preserve the GFR. Ang II inhibition suppresses this protective mechanism. In fact, any antihypertensive drug may lead to reaching a "critical perfusion pressure". ARAS should be suspected in case of renal asymmetry. It should also be envisaged in case of "flash pulmonary edemas". Ultrasonography and renal tomography show aortic calcifications and often the outline of an abdominal aortic aneurysm. Tomodensitometry may detect large aorto-renal plaques. Spiral scanner tomography represents a progress, in terms of renal artery imaging and of renal cortical atrophy. Magnetic resonance imaging is less accurate but avoids iodine toxicity. The best noninvasive method is pulsed echo-doppler. It is particularly useful for evaluating stenoses progression. Some stenoses progress to renal atrophy and renal artery thrombosis, whereas others follow a stable course. Pulsed Doppler helps predict whether revascularization will improve renal function, according to the resistance index. Renal arteriography entails a high risk of cholesterol crystal embolism. However, it is the obligatory first step for angioplasty and stent positioning, indicated when the kidney is not atrophic. The indication for revascularization essentially depends on evaluation of the benefits vs risks of angioplasty or surgery. Some publications underscore the frequent stability of renal function and the fact that, revascularized or not, most patients will shortly die of myocardial infarction. Renal cholesterol crystal embolism (CCE) is a severe condition, which occurs when large arteries undergo surgery, aortography or interventional radiology. Anticoagulants are a frequent cause of CCE. CCE may also occur spontaneously, resulting in slowly progressive renal insufficiency. Migration of crystals in small caliber intrarenal arteries induces obstruction, followed by an inflammatory reaction. The clinical picture resembles angiitis, with laboratory evidence of inflammation along with high eosinophil counts and hypocomplementemia. Diagnosis rests on: 1) a iatrogenic event in a patient with an atherosclerotic background; 2) examination of the skin disclosing purple toes, small necrotic lesions and livedo of the lower limbs. Crystals may also be found by funduscopy. Skin or muscle biopsy are contributive in showing crystals and help avoid renal biopsy; 3) other localizations involve the mesenteric circulation and the central nervous system. Until recently, the prognosis was considered disastrous. However, a recently published treatment schedule proved efficient in reducing mortality. A last issue regarding the relationships between atherosclerosis and the kidney deserves mention. In an autopsy-based study it was shown that atherosclerosis per se is accompanied by an increase in the glomerular surface area along with a greater proportion of obsolescent glomeruli by comparison with matched controls. Finally, it should be recalled that atherogenic hyperlipidemia usually aggravates the course of any renal disease, including ARAS. Treatment with statins is indicated in all forms of atherosclerotic renal disease.

A case report of type I acute aortic intramural hematoma with localized dissection as a complication of renal artery stenting

Percutaneous renal artery stenting has been demonstrated as an effective procedure to improve blood pressure control and preserve renal function of patients with artherosclerotic renal artery stenosis. Although it is a relatively safe procedure, some serious complications, including retroperitoneal hemorrhage, atheroembolism, and arterial dissection, can occur. However, development of aortic intramural hematoma (AIH), a different clinical disease entity from the aortic dissection, has not been reported as a complication of the procedure. We report a unique case with AIH that was successfully treated with medication. A 71-year-old woman with uncontrolled hypertension underwent percutaneous renal artery stenting for treatment of the ostial stenosis of the right renal artery. Immediately after implantation of the stent, she complained of severe back pain and her systolic blood pressure dropped from 170 to 80 mm Hg. Aortography showed about 5 cm-sized localized dissection arising from the ostium of the right renal artery; however, computerized tomography (CT) scans taken immediately after the procedure revealed DeBakey type I AIH with a localized dissection from the right renal artery and pericardial effusion. Because of her refusal to take surgical intervention, which is a standard treatment, she was stabilized with intensive medical treatment. After 14 days of stabilization, AIH and pericardial effusion resolved on the follow-up CT scans. Her blood pressure was well controlled with oral antihypertensive medications and she was discharged without other complication.

Ankle brachial index independently predicts early kidney disease

INTRODUCTION

Chronic kidney disease (CKD) and atherosclerotic cardiovascular disease (CVD) are often both present in selected populations. The independent association of early renal disease and atherosclerosis has not been studied in the general population. We hypothesized that the presence of low ankle brachial index (ABI), a surrogate measure of atherosclerotic cardiovascular disease, is associated with a low estimated glomerular filtration rate (GFR).

METHODS

The study population consisted of 14,917 middle-aged black and white men and women from the Atherosclerosis Risk in Communities (ARIC) Study. An ABI<0.90 was defined as the exposure, and an estimated GFR<90 mL/min/1.73 m2 was defined as the outcome. Logistic regression analysis was performed cross-sectionally using an ABI of 1.00-1.19 as the reference, and was adjusted for the usual cardiovascular risk factors.

RESULTS

The presence of an ABI<0.90 was associated with an increased odds of having an estimated GFR<90 (OR: 1.80; 95% C.I.: 1.40-2.32) compared to the reference group. After adjustment, an ABI<0.90 remained significant, and increased the odds of having an estimated GFR<90 (OR: 1.54; 95% C.I.: 1.17-2.04) compared to the reference group. The odds ratio for GFR<90 was higher among African Americans than Whites, 1.88 versus 1.36 respectively.

DISCUSSION

This study gives support to the independent association of early CKD and atherosclerotic CVD. The relationship appears to be stronger among African Americans than among Whites. It will be necessary to investigate this observation more fully with prospective studies given the rising incidence of CKD.

Renal artery calcified plaque associations with subclinical renal and cardiovascular disease

BACKGROUND

The prognostic significance of renal artery calcified plaque (RAC) and its relationship with renal function, albuminuria, and systemic atherosclerosis are unknown.

METHODS

Calcified atherosclerotic plaque was measured in the renal arteries of 96 unrelated Caucasian subjects with type 2 diabetes mellitus (DM) using four-channel multidetector-row computed tomography (MDCT4). Renal artery calcium was measured as the sum of ostial and main renal artery calcium scores. Participants also underwent MDCT scanning to measure coronary artery calcium (CAC), carotid artery calcium, common iliac artery calcium, infra-renal aorta calcium, and B-mode ultrasound to measure carotid artery intima-medial thickness (IMT). Spearman's rank correlation coefficients were used to assess associations between RAC and measures of subclinical renal and cardiovascular disease. Partial correlation coefficients were computed to adjust for the potential confounding effects of age, gender, body mass index (BMI), DM duration, smoking, and serum cholesterol and triglyceride levels.

RESULTS

Characteristics of the study group were 54% (52/96) female with a mean +/- SD (median) age 62.8 +/- 8.4 (62.5) years, DM duration 10.6 +/- 6.3 (8.0) years, hemoglobin A1C 7.5 +/- 1.5 (7.2)%, BMI 32.1 +/- 6.3 (31.1) kg/m(2), serum creatinine concentration 1.11 +/- 0.18 (1.10) mg/dL, urine albumin:creatinine ratio (ACR) 105.3 +/- 423.1 (17.6) mg/g, modified MDRD equation glomerular filtration rate (GFR) 64.3 +/- 12.6 (63.6) mL/min, RAC 372 +/- 799 (101), CAC 1819 +/- 2594 (622), carotid artery calcium 264 +/- 451 (72), and B-mode ultrasound carotid IMT 0.70 +/- 0.12 (0.69) mm. Sixty-five percent of subjects (62/96) had detectable RAC. Renal artery calcium was significantly associated with CAC (r= 0.50, P < 0.0001), carotid artery calcium (r= 0.58, P < 0.0001), common iliac artery calcium (r= 0.45, P < 0.0001), infra-renal aorta calcium (r= 0.70, P < 0.0001), IMT (r= 0.40, P= 0.0004), diastolic blood pressure (r=-0.33, P= 0.0009), BMI (r=-0.19, P= 0.0573), and age (r= 0.54, P < 0.0001). There was no association between RAC and GFR (r=-0.15, P= 0.1637) or between RAC and urine ACR (r= 0.07, P= 0.5083).

CONCLUSION

Renal artery calcium is strongly associated with older age, diastolic blood pressure, BMI, carotid artery IMT, and coronary, carotid, common iliac artery, and infra-renal aorta calcium in Caucasians with type 2 diabetes mellitus. Renal artery calcium, similar to CAC and IMT, appears to be a useful noninvasive marker of subclinical atherosclerosis. However, RAC is not significantly associated with either GFR or albuminuria.

A single chinese center investigation of renal artery stenosis in 141 consecutive cases with coronary angiography

BACKGROUND

There is an increasing prevalence of ischemic nephropathy in the aging population of the world. However, the exact incidence of ischemic nephropathy in the Chinese population is still uncertain. The present study investigated the incidence of renal artery stenosis (RAS) in patients with suspected coronary artery disease (CAD) using renal angiography.

METHODS

Renal angiography was performed immediately after coronary artery angiography in 141 patients with suspected CAD, including 59 males and 82 females whose mean ages were 59 +/- 10 years. Comorbidities included hypertension (n = 69), diabetes mellitus (n = 21), hyperlipidemia (n = 19), hypokalemia (n = 7) and preoperative renal insufficiency (Cr >132 micromol/l; n = 14). The patients were divided into CAD (luminal narrowing of > or =50%) and non-CAD (luminal narrowing of <50%) subgroups, and RAS (luminal narrowing of > or =50%) and non-RAS subgroups. In the RAS group, there were 11 patients (5 males, 6 females) in whom percutaneous transluminal renal angioplasty was performed in conjunction with stent implantation due to refractory hypertension.

RESULTS

The incidence of RAS was 18.4% (26/141) in all cases and 30.8% (16/52) in patients with CAD identified by coronary artery angiography. Ten cases with RAS were found among the 89 cases with normal coronary arteries (11.2%). The incidence of RAS in patients with CAD was higher than that in patients without CAD (30.8 vs. 11.2%, p< 0.05). In 52 cases with CAD, the incidence of RAS with three vessel lesions was significantly higher than that with one or two vessel lesions. Hypertension, CAD, renal insufficiency, hyperlipidemia and hypokalemia were associated with a higher risk of RAS.

CONCLUSIONS

This study suggests that RAS is very common in the elderly Chinese population, specifically for those with three vessel lesions in CAD. For early detection of potential ischemic nephropathy, renal angiography is necessary in patients who receive coronary artery angiography.

Effects of Losartan and Chlorthalidone on Blood Pressure and Renal Vascular Resistance Index in Non-Diabetic Patients with Essential Hypertension and Normal Renal Function

Antihypertensive drugs can differ in target organ protection despite similar blood pressure (BP) control. We compared the effects of losartan (L) and chlorthalidone (C) on renal vascular resistance index (RVRI) in 194 grade I to II, non-diabetic hypertensive patients with increased RVRI (>0.68 m/s by echo-Doppler) but normal renal function. Patients were randomly allocated to C 25 mg/d or L 50 mg/d according to a single blind, PROBE study design. After 4 weeks of treatment, 92 patients (48 L/44 C) with BP <140/90 mm Hg were enrolled in the long-term phase of the study. After 12 months a normalization of RVRI was observed in 47 of 48 patients treated with L (97.5%) and only in 14 of 44 of those treated with C (25.8%) despite no differences in BP control. Patients whose RVRI remained elevated during C therapy underwent a 2-week washout period and then were treated with L 50 mg/d for 12 additional months. After that period 28 of 30 (95%) of patients who were nonresponders to C showed a normalization of RVRI despite no differences in BP control. In conclusion, our data suggest that treatment with L can improve renal hemodynamic and exert a protective renal effect beyond BP control in patients with hypertension.

Cortical microvascular remodeling in the stenotic kidney: role of increased oxidative stress

OBJECTIVE

Mechanisms of renal injury distal to renal artery stenosis (RAS) remain unclear. We tested the hypothesis that it involves microvascular remodeling consequent to increased oxidative stress.

METHODS AND RESULTS

Three groups of pigs (n=6 each) were studied after 12 weeks of RAS, RAS+antioxidant supplementation (100 IU/kg vitamin E and 1 g vitamin C daily), or controls. The spatial density and tortuousity of renal microvessels (<500 microm) were tomographically determined by 3D microcomputed tomography. The in situ production of superoxide anion and the expression of vascular endothelial growth factor (VEGF), its receptor VEGFR-2, hypoxia-inducible-factor (HIF)-1alpha, von Hippel-Lindau (VHL) protein, and NAD(P)H oxidase (p47phox and p67phox subunits) were determined in cortical tissue. RAS and RAS+antioxidant groups had similar degrees of stenosis and hypertension. The RAS group showed a decrease in spatial density of cortical microvessels, which was normalized in the RAS+antioxidant group, as was arteriolar tortuousity. RAS kidneys also showed tissue fibrosis (by trichrome and Sirius red staining), increased superoxide anion abundance, NAD(P)H oxidase, VHL protein, and HIF-1alpha mRNA expression. In contrast, expression of HIF-1alpha, VEGF, and VEGFR-2 protein was downregulated. These were all significantly improved by antioxidant intervention.

CONCLUSIONS

Increased oxidative stress in the stenotic kidney alters growth factor activity and plays an important role in renal microvascular remodeling, which can be prevented by chronic antioxidant intervention.

Clinical benefit of renal artery angioplasty with stenting for the control of recurrent and refractory congestive heart failure

Renal artery stenosis (RAS) may cause hypertension, azotemia, episodes of flash pulmonary edema and congestive heart failure. Renal artery angioplasty and stenting was performed in 207 patients from 1991 to 1997. Thirty-nine of these patients (19%) underwent renal artery stenting for the control of recurrent episodes of congestive heart failure and flash pulmonary edema. All patients had angiographic evidence of severe (>70%) bilateral RAS (n = 18) or severe RAS to a solitary functioning kidney (n = 21). Sixteen patients (41%) were male and 23 (59%) were female, mean age 69.9 years (range 50-85 years). Of the 18 patients with bilateral RAS, 12 (66.6%) underwent bilateral stenting. Mean blood pressure decreased from 174/85 +/- 32/23 mmHg to 148/72 +/- 24/14 mmHg (p < 0.001). Mean number of blood pressure medications decreased from 3 +/- 1 to 2.5 +/- 1 (p = 0.006). Twenty-eight patients (71.8%) had improvement in blood pressure control. The mean serum creatinine decreased from 3.16 +/- 1.61 to 2.65 +/- 1.87 (p = 0.06). Six of 39 patients (15.4%) used angiotensin converting enzyme (ACE) inhibitors prior to stenting whereas 19 of 39 patients (48.7%) used ACE inhibitors poststenting (p = 0.004). Twenty of 39 patients (51.4%) demonstrated improvement in serum creatinine, 10 of 39 patients (25.6%) had stabilization of serum creatinine and nine of 39 patients (23%) demonstrated worsening. The number of hospitalizations due to congestive heart failure in the year preceding renal artery stenting was 2.4 +/- 1.4 and poststenting was 0.3 +/- 0.7 (p < 0.001). The New York Heart Association Functional Class decreased from 2.9 +/- 0.9 prestenting to 1.6 +/- 0.9 poststenting (p < 0.001). Thirty of 39 patients (77%) had no hospitalizations for congestive heart failure during a mean follow-up period of 21.3 months. Nine patients expired during the course of follow up; eight of the nine patients died within the first year after renal artery stenting. Renal artery stenting decreased the frequency of congestive heart failure, flash pulmonary edema, and the need for hospitalization in most patients. Blood pressure was markedly improved in the majority of patients with improved or stabilized renal function. Evaluation for RAS is important in hypertensive patients who present with recurrent congestive heart failure or flash pulmonary edema.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Atherosclerotic ischemic renal vascular disease: do published outcomes justify the overzealous diagnostic approaches?

Atherosclerotic renal vascular disease is being recognized more frequently in an elderly patient population with chronic kidney disease. It also is much easier to diagnose and treat, at this time, because of the wide availability of coronary angiography and other radiologic imaging studies. In general, patients with atherosclerotic ischemic renal vascular disease are much sicker than the usual ESRD patient with more cardiac comorbidity and higher mortality rates. It is important to determine whether the lesions in the renal artery are physiologically significant before performing an intervention. The interventions are often risky with significant morbidity. Nephrologists should guide their colleagues to follow prudent courses of action. There are no evidence-based guidelines in this area.

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.

Abdominal aortic aneurysm and renal artery stenosis: renal function and blood pressure before and after endovascular treatment

We describe three patients with abdominal aortic aneurysm (AAA) and renal artery stenosis (RAS). These patients were treated by placement of an aortic endograft and angioplasty or stenting of the renal artery. After the procedure renal function improved or remained stable in two patients and deteriorated slightly in one. Blood pressure was reduced in one hypertensive patient and remained normal in the other two normotensive patients. In conclusion, simultaneous treatment of AAA and RAS with aortic endograft placement and renal artery angioplasty with or without stent, is a safe and effective technique for selected high-risk patients.

Ischemic renal disease in Kuwait

Ischemic renal disease (IRD) is a frequent cause of end-stage renal disease. Its prevalence is mainly known from autopsy or retrospective arteriographic studies. This prospective study was conducted in 115 subjects selected from 732 patients with advanced chronic renal failure (CRF). Only patients with clinical features suggestive of IRD were selected for this study. In addition to detailed clinical and laboratory evaluation, captopril renal scintigraphy was performed in selected cases. All subjects underwent renal arteriography and all were followed up for 18.4 +/- 11.4 months. Renovascular disease was seen in 15 patients and significant bilateral renal artery disease leading to IRD was observed in 13 (11.3%). Hence the prevalence of IRD in the advanced CRF patients was 1.7%. The majority of patients with IRD (8 [61%]) were above 46 years of age and there were more men than women (10:3). Atherosclerotic renovascular disease was the most common (10 [77%]), even though arthritis (1 [7.6%]), and fibromuscular dysplasia (2 [15.3%]) were also observed. Serum creatinine at time of presentation was significantly higher in patients with IRD (784 +/- 292, p = 0.043) compared to those who did not have IRD (359 +/- 126). Corrective procedures were performed in 5 patients. After treatment the improvement in serum creatinine in patients with IRD at 3 and 6 months (166 +/- 32 and 173 +/- 47, respectively) was significantly different (p < or = 0.05) compared to those who were not treated (610 +/- 194 and 645 +/- 220, respectively). Hyperlipidemia, coronary artery disease and peripheral vascular disease were more prevalent in patients who had IRD compared to those with renal failure. The incidence of diabetes mellitus were similar in both groups. This study denotes a lower prevalence of IRD in the advanced CRF population; they had more severe renal failure at presentation but specific corrective treatment delayed progression of renal disease significantly.

Rapid decline in renal function reflects reversibility and predicts the outcome after angioplasty in renal artery stenosis

Percutaneous transluminal renal angioplasty (PTRA) has a beneficial effect on renal function in some, but not all, patients with atheromatous renal artery stenosis. Our aim is to identify factors influencing clinical success after PTRA in this group of patients. Seventy-three patients undergoing PTRA were studied; 14 patients were excluded from final analysis because of restenosis. All patients had chronic renal failure secondary to vascular nephropathy and renal artery stenosis. The diagnosis of renal artery stenosis was based on carbon dioxide digital angiography showing greater than 60% luminal narrowing. The rate of renal failure progression was assessed by the slope of the regression line of serum creatinine versus time. At least three consecutive creatinine measurements before and after angioplasty were required for study entry. Response to PTRA was made by comparison of the slope before and after PTRA. The association of age, serum creatinine level, proteinuria, renal size, pre-PTRA slope value, diabetes, ischemic heart disease, peripheral vascular disease, and cerebrovascular disease with response to PTRA was assessed by multiple regression analysis, with changes in slope values as the dependent variable. Renal function improved in 34 of 59 patients (57.6%). Mean follow-up was 627 +/- 284 (SD) days. The slope of the reciprocal serum creatinine plot before PTRA was significantly associated with a favorable change in progression rate after PTRA (beta = -0.012; P = 0.004). A scatter plot showed a statistically significant inverse correlation between pre-PTRA slope values and post-PTRA slope changes (r = -0.46; P = 0.000). Rapidly progressive renal failure is associated with a favorable response on renal failure progression after PTRA in patients with vascular nephropathy and renal artery stenosis.