Dialysis-associated ischemic heart disease: insights from coronary angiography

Impact of chronic kidney disease and end-stage renal disease on the mid-term adverse outcomes in diabetic patients with cardiovascular diseases

The evidence for the impact of renal dysfunction in patients with diabetes mellitus (DM) and first cardiovascular diseases on mid-term adverse outcomes remain scarce. This study included the data of patients with DM having first atherosclerotic cardiovascular disease (ASCVD) or congestive heart failure (CHF) from the Taipei Medical University Clinical Research Database. A Cox proportional hazards regression model was used to assess the impact of chronic kidney disease (CKD) or end-stage renal disease (ESRD) on the 1-year mortality and recurrent ASCVD/CHF outcomes. We enrolled 21,320 patients with DM hospitalized for ASCVD or CHF; of them, 18,185, 2639, and 496 were assigned to the non-CKD, CKD, and ESRD groups, respectively. After propensity score matching, compared with the non-CKD group, the CKD and ESRD groups had higher mid-term all-cause mortality (adjusted hazard ratio 1.72 [95% confidence interval 1.48-1.99] and 2.77 [2.05-3.73], respectively), cardiovascular death (1.84 [1.44-2.35] and 1.87 [1.08-3.24], respectively), and recurrent hospitalization for ASCVD (1.44 [1.24-1.68] and 2.33 [1.69-3.23], respectively) and CHF (2.08 [1.75-2.47] and 1.50 [1.04-2.17], respectively). The advancing age was associated with mortality in CKD/ESRD groups. In CKD group, male sex was associated with all-cause mortality and recurrent ASCVD risk; the diuretics usage was associated with mortality and recurrent CHF risks. Our findings suggest that CKD and ESRD are significant risk factors for mid-term adverse outcomes in patients with DM and established cardiovascular diseases. Additionally, old age, male sex and diuretics usage requires attention. Further good quality studies are needed in the future.

MicroRNA regulators of vascular pathophysiology in chronic kidney disease

Coronary artery disease (CAD) is a severe comorbidity in chronic kidney disease (CKD) due to heavy calcification in the medial layer and inflamed plaques. Chronic inflammation, endothelial dysfunction and vascular calcification are major contributors that lead to artherosclerosis in CKD. The lack of specific symptoms and signs of CAD and decreased accuracy of noninvasive diagnostic tools result in delayed diagnosis leading to increased mortality. MicroRNAs (miRNAs) are post-transcriptional regulators present in various biofluids throughout the body. In the circulation, miRNAs have been reported to be encapsulated in extracellular vesicles and serve as stable messengers for crosstalk among cells. miRNAs are involved in pathophysiologic mechanisms including CAD and can potentially be extended from basic research to clinical translational practice.

Major cardiovascular events and associated factors among routine hemodialysis patients with end-stage renal disease at tertiary care hospital in Somalia

Introduction

Cardiovascular complications are the most significant cause of death in patients undergoing routine hemodialysi (HD) with end-stage renal disease (ESRD). The main objective of this study is to determine the significant cardiac events and risk factors in patients undergoing routine hemodialysis in Somalia.

Methods

We carried out a cross-sectional retrospective study in a single dialysis center in Somalia. Two hundred out of 224 were included. All of them had ESRD and were on hemodialysis during the study period between May and October 2021. The records of all patients were reviewed, and the following parameters were analyzed socio-demographic factors, risk factors for cardiovascular disease, and the presence of cardiovascular diseases.

Results

The mean age was 54 ± 17.5 years (range 18-88 years), and 106 (53%) patients were males. The prevalence of a cardiovascular disease among hemodialysis patients was 29.5%. Moreover, the distribution of cardiovascular diseases was different; heart failure was the most common, about 27.1%, followed by coronary artery disease (17%), pericarditis and pericardial-effusion (13.6%), dysrhythmia (10.2%), cerebrovascular-accident (8.5%), and peripheral vascular disease (3.4%). About 176 (88%) participants had at least one modifiable cardiovascular risk factor. The most common modifiable cardiovascular risk factor was hypertension (n = 45, 25.1%), followed by anemia (n = 28, 15.6%) and diabetes (n = 26, 14.5%). Younger (18-30) participants were six times less likely to have cardiovascular events among hemodialysis than older age 0.4 (0.11-1.12).

Conclusion

Low prevalence rate of cardiovascular complications was confirmed in ESRD patients receiving hemodialysis in the main HD center in Somalia. Diabetes, anemia, and hypertension were the highest significant risk factors for CVD in HD patients with ESRD in Somalia.

A multicentre prospective double blinded randomised controlled trial of intravenous iron (ferric Derisomaltose (FDI)) in Iron deficient but not anaemic patients with chronic kidney disease on functional status

BACKGROUND

Iron deficiency (ID) is common in patients with chronic kidney disease (CKD). Intravenous (IV) iron in heart failure leads to improvement in exercise capacity and improvement in quality-of-life measurements; however, data in patients with CKD are lacking.

METHODS

The Iron and the Heart Study was a prospective double blinded randomised study in non-anaemic CKD stages 3b-5 patients with ID which investigated whether 1000 mg of IV iron (ferric derisomaltose (FDI)) could improve exercise capacity in comparison to placebo measured at 1 and 3 months post infusion. Secondary objectives included effects on haematinic profiles and haemoglobin, safety analysis and quality of life questionnaires (QoL).

RESULTS

We randomly assigned 54 patients mean (SD) age for FDI (n = 26) 61.6 (10.1) years vs placebo (n = 28; 57.8 (12.9) years) and mean eGFR (33.2 (9.3) vs. 29.1 (9.6) ml/min/1.73m2) at baseline, respectively. Adjusting for baseline measurements, six-minute walk test (6MWT) showed no statistically significant difference between arms at 1 month (p = 0.736), or 3 months (p = 0.741). There were non-significant increases in 6MWT from baseline to 1 and 3 months in the FDI arm. Haemoglobin (Hb) at 1 and 3 months remained stable. There were statistically significant increases in ferritin (SF) and transferrin saturation (TSAT) at 1 and 3 months (p < 0.001). There was a modest numerical improvement in QoL parameters. There were no adverse events attributable to IV iron.

CONCLUSION

This study demonstrated a short-term beneficial effect of FDI on exercise capacity, but it was not significant despite improvements in parameters of iron status, maintenance of Hb concentration, and numerical increases in functional capacity and quality of life scores. A larger study will be required to confirm if intravenous iron is beneficial in iron deficient non-anaemic non-dialysis CKD patients without heart failure to improve the 6MWT.

TRIAL REGISTRATION

European Clinical Trials Database (EudraCT) No: 2014-004133-16 REC no: 14/YH/1209 Date First Registered: 2015-02-17 and date of end of trail 2015-05-23 Sponsor ref R1766 and Protocol No: IHI 141.

Influenza vaccination reduces incidence of peripheral arterial occlusive disease in elderly patients with chronic kidney disease

An influenza vaccination might reduce the risk of incident peripheral arterial occlusive disease (PAOD) in patients with chronic kidney disease (CKD), but supporting evidence is limited. This case-crossover study analyzed data from Taiwan's real-world National Health Insurance Research Database. This study included elderly (≥ 67 years old) patients with CKD having incident PAOD from January 1, 2006, to June 30, 2015. We defined 1 year before PAOD onset as the index date for the self-control group. A conditional logistic regression model was used to investigate exposure to an influenza vaccination for estimating the risk for incident PAOD following vaccination. In total, this study included 46,782 elderly patients with CKD having incident PAOD. The odds ratios for incident PAOD were 0.85 (95% confidence interval 0.77-0.94), 0.85 (0.79-0.92), 0.84 (0.79-0.90), and 0.85 (0.81-0.90) at 1, 2, 3, and 4 months after an influenza vaccination, respectively. We observed consistent results for the subgroups of patients with CKD and concomitant diabetes. However, we did not observe any beneficial effects of influenza vaccination in patients with advanced CKD or end-stage renal disease. This study demonstrated that influenza vaccination may be associated with a reduced risk of incident PAOD among patients with early-stage CKD.

Uraemic Cardiomyopathy: A Review of Current Literature

Uraemic Cardiomyopathy (UC) is recognised as an intricate and multifactorial disease which portends a significant burden in patients with End-Stage Renal Disease (ESRD). The cardiovascular morbidity and mortality associated with UC is significant and can be associated with the development of arrythmias, cardiac failure and sudden cardiac death (SCD). The pathophysiology of UC involves a complex interplay of traditional implicative factors such as haemodynamic overload and circulating uraemic toxins as well as our evolving understanding of the Chronic Kidney Disease-Mineral Bone Disease pathway. There is an instrumental role for multi-modality imaging in the diagnostic process; including transthoracic echocardiography and cardiac magnetic resonance imaging in identifying the hallmarks of left ventricular hypertrophy and myocardial fibrosis that characterise UC. The appropriate utilisation of the aforementioned diagnostics in the ESRD population may help guide therapeutic approaches, such as pharmacotherapy including beta-blockers and aldosterone-antagonists as well as haemodialysis and renal transplantation. Despite this, there remains limitations in effective therapeutic interventions for UC and ongoing research on a cellular level is vital in establishing further therapies.

[Preparation of the dialysis patient with type 1 diabetes mellitus for kidney transplantation]

Kidney transplantation is unique method of renal replacement therapy, allowing to improve quality and duration of life for patients with diabetes mellitus type 1 (DM1) and end-stage renal disease (ESRD) on dialysis therapy. Recently using of innovation technologies for diabetes management and modern immunosuppression enable achieving better results of posttransplant rehabilitation for patients with DM1, especially if kidney transplantation is performed early after initiation of dialysis. Detailed examination of patient with DM1 before potential kidney transplantation is very important to reduce of early and late postoperative complications. Kidney transplantation preparation includes effective glycemic control, adequate dialysis therapy, treatment of diabetes and ESRD complications and concomitant conditions, especially cardiovascular diseases, accounting for kidney transplantation perspective. Furthermore, diagnostics and treatment of any infectious process, timely vaccination, cancer screening are basic approaches of kidney transplantation preparation program, providing the best survival rate of kidney graft and patient.

A comparison of the risk of acute myocardial infarction in patients receiving hemodialysis and peritoneal dialysis: A population-based, propensity score-matched cohort study

BACKGROUND AND AIMS

Acute myocardial infarction (AMI) remains the major cause of morbidity and mortality in the dialysis population. Traditional cardiovascular (CV) risk factors are unable to fully account for the high incidence of AMI in the dialysis population. In this study, we investigated whether dialysis modalities could be one of the uremia-specific risk factors for AMI.

METHODS

Using the National Health Insurance Research Database, we recruited all incident dialysis patients from the period January 1, 1998 to December 31, 2010. The propensity score matching method was applied to form the matched pairs of hemodialysis (HD) and peritoneal dialysis (PD) patients. Incidence rate (IR), cumulative incidence rate (CIR) and multivariable subdistribution hazards models were employed to compare the risk of AMI in the HD and PD groups.

RESULTS

Of the 86,215 incident dialysis patients, 5,513 matched pairs of HD and PD patients were identified. The HD patients had a higher IR of AMI than the PD patients (9.71 vs. 8.35 per 1000 patient-years, respectively, p = 0.01). The CIR was also higher in the HD patients than in the PD patients (0.09 vs. 0.05), especially 4 years after dialysis therapy was initiated (p = 0.04). In the subdistribution hazards models, HD was still significantly associated with a higher risk of developing AMI (adjusted hazard ratio:1.30, 95% confidence interval:1.02-1.65). The results remained unchanged in various stratifications as well as in the analysis of the unmatched cohorts.

CONCLUSIONS

Compared to PD, HD was significantly associated with higher risk of developing AMI, especially after 4 years since dialysis was initiated. Prevention and routine surveillance programs for AMI should be individualized according to dialysis modalities and vintage.

Effective Continuous Ambulatory Peritoneal Dialysis following Abdominal Aortic Aneurysm Repair

+ Objective

To review a single center's experience with the initiation and maintenance of continuous ambulatory peritoneal dialysis (CAPD) in 8 patients with a history of abdominal aortic aneurysm repair (AAAR).

+ Design

Retrospective case review with long-term follow-up.

+Patients (or Participants)

Eight patients with multiple medical problems including a history of abdominal aortic aneurysm repair and end-stage renal failure who received peritoneal dialysis catheters between December 1986 and July 1991.

+ Main Outcome Measures

Success of catheter implantation and maintenance of continuous ambulatory peritoneal dialysis; incidence of peritoneal infection and long-term complications; overall clinical course.

+ Results

Over five years 8 patients with a history of reconstructed abdominal aortic aneurysm received peritoneal dialysis catheters without complication and dialyzed successfully for 88 patient-months in total. Three patients had a total of five episodes of peritonitis, at an incidence of 0.68 episodes per patient per year, a rate not significantly different from that of our overall CAPD patient population (1.09) and that reported by other groups.

+ Conclusion

Our experience suggests that historical AAAR poses no significant risk to and should not preclude the implementation of continuous ambulatory peritoneal dialysis. Indeed, CAPD offers a safe and optimal dialytic alternative for patients with historical abdominal aortic aneurysm repair in whom compromised cardiovascular hemodynamics may significantly influence morbidity and survival.

Kidney transplantation and cardiomyopathy: Concepts and controversies in clinical decision-making

Increasing comorbidities and an aging population have led to a tremendous increase in the burden of both kidney and cardiac dysfunction. Concomitant cardiomyopathy exposes the patients with kidney disease to further physiological, hemodynamic, and pathologic alterations. Kidney transplantation imposes lesser anesthetic and surgical complexities compared to another solid organ transplant. The surgical decision-making remains an unsettled issue in these conditions. The surgical choices, techniques, and sequences in kidney transplant and cardiac surgery depend on the pathophysiological perturbations and perioperative outcomes. The absence of randomized controlled trials eludes us from suggesting definite management protocol in patients with end-stage kidney disease with cardiomyopathy. Nevertheless, in this review, we extracted data from published literature to understand the pathophysiologic interactions between end-stage renal diseases with cardiomyopathy and also proposed the management algorithm in this challenging scenario. The proposed management algorithm would ensure consensus across all stakeholders involved in decision-making. Our simplistic evidence-based approach would augur future randomized trials and would further ensure refinement in our management approach after the emergence of more definitive evidence.

miR-26a Limits Muscle Wasting and Cardiac Fibrosis through Exosome-Mediated microRNA Transfer in Chronic Kidney Disease

Uremic cardiomyopathy and muscle atrophy are associated with insulin resistance and contribute to chronic kidney disease (CKD)-induced morbidity and mortality. We hypothesized that restoration of miR-26a levels would enhance exosome-mediated microRNA transfer to improve muscle wasting and cardiomyopathy that occur in CKD.

Methods: Using next generation sequencing and qPCR, we found that CKD mice had a decreased level of miR-26a in heart and skeletal muscle. We engineered an exosome vector that contained Lamp2b, an exosomal membrane protein gene fused with a muscle-specific surface peptide that targets muscle delivery. We transfected this vector into muscle satellite cells and then transduced these cells with adenovirus that expresses miR-26a to produce exosomes encapsulated miR-26a (Exo/miR-26a). Exo/miR-26a was injected once per week for 8 weeks into the tibialis anterior (TA) muscle of 5/6 nephrectomized CKD mice.

Results: Treatment with Exo/miR-26a resulted in increased expression of miR-26a in skeletal muscle and heart. Overexpression of miR-26a increased the skeletal muscle cross-sectional area, decreased the upregulation of FBXO32/atrogin-1 and TRIM63/MuRF1 and depressed cardiac fibrosis lesions. In the hearts of CKD mice, FoxO1 was activated, and connective tissue growth factor, fibronectin and collagen type I alpha 1 were increased. These responses were blunted by injection of Exo/miR-26a. Echocardiograms showed that cardiac function was improved in CKD mice treated with Exo/miR-26a.

Conclusion: Overexpression of miR-26a in muscle prevented CKD-induced muscle wasting and attenuated cardiomyopathy via exosome-mediated miR-26a transfer. These results suggest possible therapeutic strategies for using exosome delivery of miR-26a to treat complications of CKD.

Are Lipid Abnormalities Reliable Cardiovascular Risk Factors in Dialysis Patients?

Patients on chronic hemodialysis often present both hyperlipidemia and a high incidence of cardiovascular disease (CVD). Uremic hyperlipidemia has usually been regarded as one of the most important cardiovascular risk factors (CVRF) in these patients. In order to study whether the “uremia-induced” lipid abnormalities are actually associated with evidence of uremic CVD, and consequently may be considered reliable CVRF, 123 patients on chronic dialysis were reviewed for the presence of CVD and, at the same time, examined for their lipoprotein pattern and other clinical and biochemical variables.

Lipids and lipoproteins did not prove helpful in our study in identifying patients with CVD. Despite the fact that they had been on dialysis for a shorter time, CVD patients were significantly older and had higher blood pressure than patients without CVD. Our data suggest that the uremia-induced lipid abnormalities are not reliable markers of CVD in dialysis patients, and support the hypothesis that dialysis per se does not accelerate the atherosclerotic process in uremic patients

Coronary Angiography Profile at the Time of Hemodialysis Initiation in End-Stage Renal Disease Population: A Retrospective Analysis

Cardiovascular disease is associated with increased mortality in dialysis population. However, there are very few studies that assessed the prevalence of coronary artery disease (CAD) at the time of initiation of hemodialysis (HD). The present study was aimed to assess the prevalence of CAD in end-stage renal disease (ESRD) patients at the time of initiation of HD and the risk factors for CAD in this population. This was a single-center retrospective study and included ESRD patients who underwent coronary angiography (CAG) at the time of initiation of HD. Inclusion criteria were age >18 years and those who were subjected to CAG within 2 weeks of initiation of HD. According to the findings on CAG, patients were divided into no CAD and CAD groups. CAD was diagnosed if there was >50% stenosis of vessel. Clinical and laboratory parameters between these two groups were analyzed. Ninety-seven patients were included in the study based on the inclusion criteria. Forty-four (45%) patients were diagnosed with CAD. Patients who had CAD were younger compared to no CAD group (50.7 + 10 vs. 55.8 + 9.3 years; P = 0.01). Majority of them were males. Diabetic nephropathy (DN) was associated with increased risk of CAD (60% vs. 40%, P = 0.007). History of smoking, high high-sensitivity C-reactive protein (hs-CRP), low total cholesterol, and low high-density lipoprotein (HDL) were associated with significantly increased risk of CAD. Gender, symptoms of CAD, serum low-density lipoprotein (LDL), very LDL, and triglycerides were not associated with increased risk of CAD. Neither calcium (Ca), phosphorus (PO₄), nor Ca × PO₄products were associated with an increased risk of CAD. Resting electrocardiogram abnormalities had no significance in predicting CAD (32% in CAD and 19% in no CAD group). Echocardiography showed regional wall motion abnormalities/global hypokinesia in 18% patients of CAD group and 3.8% patients of no CAD group (P = 0.03). Single-, double-, and triple-vessel disease was documented in 17 (38%), 13 (29.5%), and 14 (32.5%) patients, respectively, and the most common vessel involved was the left anterior descending artery. At the initiation of HD in ESRD patients, CAD was seen in almost half of the patients. DN was a significant risk factor for CAD. Other risk factors for CAD include smoking, low cholesterol, low HDL, and high hs-CRP levels.

Cardiotoxicity of Uremic Toxins: A Driver of Cardiorenal Syndrome

Cardiovascular disease (CVD) is highly prevalent in the setting of chronic kidney disease (CKD). Such coexistence of CVD and CKD—the so-called “cardiorenal or renocardiac syndrome”—contributes to exponentially increased risk of cardiovascular (CV) mortality. Uremic cardiomyopathy is a characteristic cardiac pathology commonly found in CKD. CKD patients are also predisposed to heart rhythm disorders especially atrial fibrillation. Traditional CV risk factors as well as known CKD-associated CV risk factors such as anemia are insufficient to explain CV complications in the CKD population. Accumulation of uremic retention solutes is a hallmark of impaired renal excretory function. Many of them have been considered inert solutes until their biological toxicity is unraveled and they become accepted as “uremic toxins”. Direct cardiotoxicity of uremic toxins has been increasingly demonstrated in recent years. This review offers a mechanistic insight into the pathological cardiac remodeling and dysfunction contributed by uremic toxins with a main focus on fibroblastic growth factor-23, an emerging toxin playing a central role in the chronic kidney disease–mineral bone disorder, and the two most investigated non-dialyzable protein-bound uremic toxins, indoxyl sulfate and p-cresyl sulfate. Potential therapeutic strategies that could address these toxins and their relevant mediated pathways since pre-dialysis stages are also discussed.

Dipyridamole Thallium-201 Perfusion Imaging for the Study of Ischemic Heart Disease in Hemodialysis Patients

To assess the usefulness of dipyridamole thallium perfusion imaging in the evaluation of myocardial perfusion in hemodialysis (HD), we studied 29 HD patients divided into three groups: A) 13 patients with clinical angina, B) 8 patients without angina but similar in age, sex, time on HD and hematocrit and C) 8 young asymptomatic patients (mean age 33 ± 9.7 years). Dipyridamole thallium-201 (TI-201) perfusion imaging revealed myocardial perfusion defects in 8 patients (61%) from group A, 4 (50%) from group B and 1 (12.5%) from group C. These defects were localized in the inferior, posterior and septal segments of the left ventricle. Abnormal myocardial perfusion was associated with age over 50 years and aortic calcifications (p < 0.05). Eight patients died within the following four years. All had aortic calcifications (p < 0.001). Our results show that myocardial perfusion defects are frequent even in non-symptomatic HD patients. This suggests that ischemic heart disease could be more frequent than estimated by clinical symptoms alone. TI-201 scintigraphy may be a useful non-invasive procedure in cardiological evaluation of HD patients

Cardiac Pathology in Patients with End-Stage Renal Disease Maintained on Hemodialysis

We report the spectrum of cardiovascular pathology found on autopsy examination in 106 consecutive patients with end-stage renal disease. Cardiovascular pathology was present in nearly all patients, and was the most frequent cause of death (36%), with acute myocardial infarction accounting for 15%. Particularly frequent pathologic findings were left ventricular hypertrophy, coronary and aortic atherosclerosis, pericarditis with effusion, myocardial fibrosis, and valvular dilatation. Cardiovascular death rate was higher during the first year than after the fifth year of dialysis. Nearly all patients had a history of hypertension. The nature of the underlying cause of renal failure and pre-existing cardiovascular disease, specifically diabetes mellitus and hypertension, were the principal predictors of cardiovascular mortality rather than maintenance hemodialysis therapy per se.

Troponins in Renal Dysfunction

“I have yet to see any problem, however complicated, which, when you looked at it in the right way, did not become still more complicated.”

Poul (William) Anderson

Arteriosclerosis in Dialysis Patients

Arteriosclerosis is a constant problem in long-term hemodialysis patients. Computer tomography of the abdominal aorta allows a well-defined and reproducible evaluation of aortosclerosis. In the cross-sectional study, aortosclerosis was significantly accelerated in 84 chronic hemodialysis patients and was comparable to the results found in 20-year older control patients without renal disease. The increase of aortosclerosis correlated significantly with age of the patient, smoking, and duration of dialysis therapy. Furthermore, increased VLDL cholesterol and decreased HDL cholesterol seem to enhance aortosclerosis in our dialysis patients. In the longitudinal study (two CT scans with a time interval of 87 ± 62.7 months) in 36 dialysis patients, progressed aortosclerosis correlated significantly with the long duration of hypertriglyceridemia, VLDL cholesterol, uric acid, and calcium phosphate products. Progression of aortosclerosis was reduced in parathyroidectomized patients. The study suggests that premature aortosclerosis is found in dialysis patients. In addition to the common risk factor of aortosclerosis, disturbed calcium phosphate and parathyroid hormone metabolism seem to enhance aortosclerosis in patients under maintenance hemodialysis.

Hypertension, type IV cardiorenal syndrome and chronic kidney disease: Pathophysiological and therapeutical approach

Hypertension represent one of the most important comorbid factors in chronic kidney disease (CKD) patients and its prevalence increases from 65% to 95% according to glomerular filtration rate decline. CKD patients need to maintain their blood pressure levels into 130/80 mmHg according to most recent guidelines. Despite of many therapeutic agents, achievement of ideal blood pressure levels remains so far from the ideal ones. Hypertensive disease represent most important risk factor to develop a type IV cardiorenal syndrome, while prevalence of end stage renal disease is still raising and it represents worldwide epidemiological challenge. Correct management of hypertensive disease can obtain better control on CKD progression.

Cardiovascular Disease in Patients with End-Stage Renal Disease on Hemodialysis

Cardiovascular disease is a major concern for patients with end-stage renal disease (ESRD), especially those on hemodialysis. ESRD patients with coronary artery disease often do not have symptoms or present with atypical symptoms. Coronary lesions in ESRD patients are characterized by increased media thickness, infiltration and activation of macrophages, and marked calcification. Several studies showed worsened clinical outcomes after coronary revascularization, which were dependent on the severity of renal dysfunction. ESRD patients on hemodialysis have the most severe renal dysfunction; thus, the clinical outcomes are worse in these patients than in those with other types of renal dysfunction. Medications for primary or secondary cardiovascular prevention are also insufficient in ESRD patients. Efficacy of drug-eluting stents is inferior in ESRD patients, compared to the excellent outcomes observed in patients with normal renal function. Unsatisfactory outcomes with trials targeting cardiovascular disease in patients with ESRD emphasize a large potential to improve outcomes. Thus, optimal strategies for diagnosis, prevention, and management of cardiovascular disease should be modified in ESRD patients.

Anaemia and early phase cardiovascular events on haemodialysis

Although the mechanism of the cardio-renal anaemia syndrome (CRAS) has been elucidated in considerable detail over the past decade, cardiovascular disease (CVD) remains a leading cause of death among patients with end-stage kidney disease (ESKD) undergoing haemodialysis, and these patients' cardiovascular mortality is greater than that of the general population. Recent studies have reported that the CVD risk increases with advancing chronic kidney disease (CKD) stage. Furthermore, the incidence of cardiovascular events is highest during the first week after dialysis initiation, with increased risk in incident haemodialysis patients. This accumulated evidence demonstrates that how patients are managed during the pre-dialysis phase may have important implications on long-term outcomes in ESKD. Anaemia, a non-traditional risk factor for CVD, advances exponentially along with declining kidney function due to insufficient erythropoietin production. Anaemia causes functional abnormalities of the heart, as represented by cardiac hypertrophy, which results from increased cardiac workload induced by an increased preload. Left ventricular hypertrophy (LVH), a traditional risk factor for CVD, is especially associated with advanced CKD stage and could be a major risk factor for cardiovascular complications such as ischaemic heart disease, heart failure, and sudden cardiac death. In ESKD, anaemia develops more severely and requires a higher amount of erythropoiesis-stimulating agent (ESA) therapy before dialysis initiation. This suggests that improvement in anaemia management during the pre-dialysis phase may have a beneficial effect on cardiac hypertrophy and contribute to reducing the CVD risk after initiating haemodialysis.

Ischemic Heart Disease in Patients with End-Stage Kidney Disease

BACKGROUND

It was recently reported that the severity of coronary and carotid atherosclerosis in patients with end-stage kidney disease (ESKD) has improved over the last two decades. However, the frequency of coronary artery events observed at the initiation of dialysis remains high.

SUMMARY

Recently, 5 different clinical types of acute myocardial infarction (MI) were introduced in the third universal definition of MI. Type 2 MI, known as secondary MI, is a more heterogeneous entity, where a condition other than coronary artery narrowing contributes to an acute imbalance in oxygen supply and demand. In patients with chronic kidney disease, it has been demonstrated that type 2 MI is more common than type 1 MI, which is associated with coronary occlusive disease. It is suspected that patients with ESKD also often have type 2 MI. Factors associated with incremental increases in oxygen demand may cause myocardial ischemia in ESKD.

KEY MESSAGES

Significant epicardial coronary narrowing might not be a necessary precursor of myocardial ischemia in ESKD. To prevent ischemic heart disease and improve prognosis in patients with ESKD, we need to pay attention not only to coronary stenotic lesions, but also to the factors associated with the induction of an imbalance in myocardial oxygen supply and demand.

Frequency and clinical predictors of coronary artery disease in chronic renal failure renal transplant candidates

BACKGROUND/AIMS

Cardiovascular diseases are major causes of mortality in chronic renal failure patients before and after renal transplantation. Among them, coronary disease presents a particular risk; however, risk predictors have been used to diagnose coronary heart disease. This study evaluated the frequency and importance of clinical predictors of coronary artery disease in chronic renal failure patients undergoing dialysis who were renal transplant candidates, and assessed a previously developed scoring system.

METHODS

Coronary angiographies conducted between March 2008 and April 2013 from 99 candidates for renal transplantation from two transplant centers in São Paulo state were analyzed for associations between significant coronary artery diseases (≥70% stenosis in one or more epicardial coronary arteries or ≥50% in the left main coronary artery) and clinical parameters.

RESULTS

Univariate logistic regression analysis identified diabetes, angina, and/or previous infarction, clinical peripheral arterial disease and dyslipidemia as predictors of coronary artery disease. Multiple logistic regression analysis identified only diabetes and angina and/or previous infarction as independent predictors.

CONCLUSION

The results corroborate previous studies demonstrating the importance of these factors when selecting patients for coronary angiography in clinical pretransplant evaluation.

Cardiorenal syndrome: acute kidney injury secondary to cardiovascular disease and role of protein-bound uraemic toxins

Cardiovascular disease (CVD) and kidney disease are closely interrelated. Disease of one organ can induce dysfunction of the other, ultimately leading to failure of both. Clinical awareness of synergistic adverse clinical outcomes in patients with coexisting CVD and kidney disease or 'cardiorenal syndrome (CRS)' has existed. Renal dysfunction, even mild, is a strong independent predictor for poor prognosis in CVD patients. Developing therapeutic interventions targeting acute kidney injury (AKI) has been limited due mainly to lack of effective tools to accurately detect AKI in a timely manner. Neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 have been recently demonstrated to be potential candidate biomarkers in patients undergoing cardiac surgery. However, further validation of AKI biomarkers is needed in other CVD settings, especially acute decompensated heart failure and acute myocardial infarction where AKI commonly occurs. The other concern with regard to understanding the pathogenesis of renal complications in CVD is that mechanistically oriented studies have been relatively rare. Pre-clininal studies have shown that activation of renal inflammation-fibrosis processes, probably triggered by haemodynamic derangement, underlies CVD-associated renal dysfunction. On the other hand, it is postulated that there still are missing links in the heart-kidney connection in CRS patients who have significant renal dysfunction. At present, non-dialysable protein-bound uraemic toxins (PBUTs) appear to be the main focus in this regard. Evidence of the causal role of PBUTs in CRS has been increasingly demonstrated, mainly focusing on indoxyl sulfate (IS) and p-cresyl sulfate (pCS). Both IS and pCS are derived from colonic microbiotic metabolism of dietary amino acids, and hence the colon has become a target of treatment in addition to efforts to improve dialysis techniques for better removal of PBUTs. Novel therapy targeting the site of toxin production has led to new prospects in early intervention for predialysis patients with chronic kidney disease.

Cardiorenal syndrome

Cardiorenal syndrome (CRS) includes a broad spectrum of diseases within which both the heart and kidneys are involved, acutely or chronically. An effective classification of CRS in 2008 essentially divides CRS in two main groups, cardiorenal and renocardiac CRS, based on primum movens of disease (cardiac or renal); both cardiorenal and renocardiac CRS are then divided into acute and chronic, according to onset of disease. The fifth type of CRS integrates all cardiorenal involvement induced by systemic disease. This article addresses the pathophysiology, diagnosis, treatment, and outcomes of the 5 distinct types of CRS.

Usefulness of multidetector row computed tomography for predicting cardiac events in asymptomatic chronic kidney disease patients at the initiation of renal replacement therapy

Background. The prevalence of coronary artery stenosis (CAS) at the initiation of renal replacement therapy (RRT) in chronic kidney disease (CKD) patients has not been fully elucidated. Although coronary angiography is the gold standard in diagnosing CAS its invasiveness and economic burden lead to searching for a noninvasive alternative method. In this study, we evaluated the prevalence of CAS by multidetector row computed tomography (MDCT) and related risk factor to articulate the usefulness of MDCT. Method. Seventy-four asymptomatic CKD patients who began dialysis were evaluated with echocardiography and MDCT. The patients were stratified into two groups according to CAS and coronary artery calcification score (CACS) by MDCT to detect silent CAS and evaluate its predictability for cardiac events. Results. CAS was seen in 24 (32.4%) of 74 asymptomatic CKD patients on MDCT. Both groups showed increasing frequencies of CAS with age (P < 0.01), presence of diabetes (P < 0.05), uric acid level (P < 0.01), and calcium score (P < 0.01). Multiple regression analysis revealed that age and uric acid level were independent risk factors for CAS and high CACS in asymptomatic CKD patients at the initiation of dialysis. Patients with both CAS and high CACS were presented with higher cardiac events rates compared to those without any of them. In Cox regression model, age and the presence of CAS and high CACS on MDCT were an independent risk factor for cardiac events in these patients. Conclusion. We showed that CAS was highly seen in asymptomatic CKD patients starting dialysis. Moreover, both high CACS and CAS on MDCT might predict cardiac events in these patients and MDCT can be a useful screening tool for evaluating coronary artery disease and predicting cardiovascular mortality noninvasively.

Cardiac function and tolerance to ischemia-reperfusion injury in chronic kidney disease

BACKGROUND

Cardiac dysfunction is an independent risk factor of ischemic heart disease and mortality in chronic kidney disease (CKD) patients, yet the relationship between impaired cardiac function and tolerance to ischemia-reperfusion (IR) injury in experimental CKD remains unclear.

METHODS

Cardiac function was assessed in 5/6 ablation-infarction (AI) and sham male Sprague-Dawley rats at 20 weeks of age, 8 weeks post-surgery using an isolated working heart system. This included measures taken during manipulation of preload and afterload to produce left ventricular (LV) function curves as well as during reperfusion following a 15-min ischemic bout. In addition, LV tissue was used for biochemical tissue analysis.

RESULTS

Cardiac function was impaired in AI animals during preload and afterload manipulations. Cardiac functional impairments persisted post-ischemia in the AI animals, and 36% of AI animals did not recover sufficiently to achieve aortic overflow following ischemia (versus 0% of sham animals). However, for those animals able to withstand the ischemic perturbation, no difference was observed in percent recovery of post-ischemic cardiac function between groups. Urinary NOx (nitrite + nitrate) excretion was lower in AI animals and accompanied by reduced LV endothelial nitric oxide synthase and NOx. LV antioxidants superoxide dismutase-1 and -2 were reduced in AI animals, whereas glutathione peroxidase-1/2 as well as NADPH-oxidase-4 and H(2)O(2) were increased in these animals.

CONCLUSIONS

Impaired cardiac function appears to predispose AI rats to poor outcomes following short-duration ischemic insult. These findings could be, in part, mediated by increased oxidative stress via nitric oxide-dependent and -independent mechanisms.

Serum catalytic Iron: A novel biomarker for coronary artery disease in patients on maintenance hemodialysis

Cardiovascular disease is the leading cause of morbidity and mortality in maintenance hemodialysis (MHD) patients. We evaluated the role of serum catalytic iron (SCI) as a biomarker for coronary artery disease (CAD) in patients on MHD. SCI was measured in 59 stable MHD patients. All patients underwent coronary angiography. Significant CAD was defined as a > 70% narrowing in at least one epicardial coronary artery. Levels of SCI were compared with a group of healthy controls. Significant CAD was detected in 22 (37.3%) patients, with one vessel disease in 14 (63.63%) and multi-vessel disease in eight (36.36%) patients. The MHD patients had elevated levels of SCI (4.70 ± 1.79 μmol/L) compared with normal health survey participants (0.11 ± 0.01 μmol/L) (P < 0.0001). MHD patients who had no CAD had SCI levels of 1.36 ± 0.34 μmol/L compared with those having significant CAD (8.92 ± 4.12 μmol/L) (P < 0.0001). Patients on MHD and diabetes had stronger correlation between SCI and prevalence of CAD compared with non-diabetics. Patients having one vessel disease had SCI of 8.85 ± 4.67 μmol/L versus multi-vessel disease with SCI of 9.05 ± 8.34 μmol/L, P = 0.48. In multivariate analysis, SCI and diabetes mellitus were independently associated with significant CAD. We confirm the high prevalence of significant CAD in MHD patients. Elevated SCI levels are associated with presence of significant coronary disease in such patients. The association of SCI is higher in diabetic versus the non-diabetic subgroup. This is an important potentially modifiable biomarker of CAD in MHD patients.

Venous and arterial disease in inflammatory bowel disease

Awareness is increasing that risk of venous thromboembolism and development of atherosclerosis is elevated in patients with some chronic inflammatory diseases. This review aimed to examine the risk of vascular disease in patients with inflammatory bowel disease (IBD) and to identify potential pathogenic mechanisms and therapeutic approaches. An extensive literature search was conducted using MEDLINE database, Cochrane Library and international conference abstracts for studies pertaining to venous and arterial thromboembolism in adult IBD patients. There is a 1.1-3.6 fold risk of venothromboembolism in IBD, affecting 0.55-6.15% of patients. Risks are increased during a flare or with chronically active inflammation. Evidence is building that there may be a modestly increased risk of arterial disease overall, despite evidence that traditional risk factors may be reduced. Multiple pathogenic factors have been identified including endothelial dysfunction, inflammation-mediated calcium deposition in the media of arteries, hyperhomocysteinemia, platelet activation, and altered coagulation and fibrinolysis. The key to active and preventive therapy is to effectively treat inflammation. Recommendations for prophylaxis of venothromboembolism have followed guidelines where they exist and have been extrapolated from studies of other at-risk conditions, as have those for arterial disease, where screening for risk factors and actively treating abnormalities is encouraged. In conclusion, patients with IBD are at considerably increased risk of venothromboembolism and probably of arterial disease, in particular mesenteric ischemia and ischemic heart disease. Increased penetration of gaps between this knowledge and clinical therapeutic action to prevent thromboembolic events into IBD clinical practice is needed.

Cardiorenal syndrome: the emerging role of protein-bound uremic toxins

Cardiorenal syndrome is a condition in which a complex interrelationship between cardiac dysfunction and renal dysfunction exists. Despite advances in treatment of both cardiovascular and kidney disease, cardiorenal syndrome remains a major global health problem. Characteristic of the pathophysiology of cardiorenal syndrome is bidirectional cross-talk; mediators/substances activated by the disease state of 1 organ can play a role in worsening dysfunction of the other by exerting their biologically harmful effects, leading to the progression of the syndrome. Accumulation of uremic toxins is a hallmark of renal excretory dysfunction. Removal of some toxins by conventional dialysis is particularly problematic because of their high protein binding. In this review, we demonstrate that protein-bound uremic toxins may play an important role in progression of cardiovascular disease in the setting of chronic kidney disease. The highly protein-bound uremic toxin indoxyl sulfate has emerged as a potent toxin adversely affecting both the kidney and heart. Direct cardiac effects of this toxin have been recently demonstrated both in vitro and in vivo. Specifically, potent fibrogenic and prohypertrophic effects, as well as oxidative stress-inducing effects, appear to play a central role in both renal and cardiac pathology. Many of these adverse effects can be suppressed by use of a gut adsorbent, AST-120. Potential mechanisms underlying indoxyl sulfate-induced cardiorenal fibrosis are discussed. Future research and clinical implications conclude this review.

Systolic Heart Function, Kidney Filtration and the Number of Coronary Atherosclerotic Plaques in Lean and Overweight Patients

The objective of this study was to quantify the number of vessels with stenotic points in the coronary circulation of lean and overweight individuals submitted to coronary angiography and ventriculography to verify the possible associations with glomerular filtration and the systolic ventricular function. Eighty-six patients with a previous history of myocardial ischemia were studied. Two groups were formed: non-elderly (G1), n = 38, 52.8 ± 1.2 years old, and elderly (G2), n = 48, 70.1 ± 1.2 years old. Both groups were divided into 2 subgroups according to the estimated glomerular filtration rate (eGFR): ≥60 and <60 ml/min/m(2). The results showed that G1 had 0.36 ± 0.11 versus 1.25 ± 0.45 stenoses/patient (≥60 vs. <60 ml/min/m(2); p < 0.05, respectively) and G2 had 0.91 ± 0.28 versus 1.83 ± 0.33 stenoses/patient (≥60 vs. <60 ml/min/m(2), respectively). The other variables, such as central and brachial arterial blood pressures, did not manifest significant differences in relation to the eGFR. The following significant correlations were observed: between the quantity of coronary stenotic points and the eGFR (R(2) = 11.2%; r = -0.33; p < 0.001), and between eGFR and the ventricular ejection fraction (R(2) = 5.1%; r = 0.57; p < 0.0001). The ejection fraction correlated significantly with the number of vessels with stenoses in the coronary bed (R(2) = 13.4%; r = -0.36; p < 0.008). In conclusion, although the correlations are considered weak, interrelationships between heart and kidney were demonstrated in this study.

Cardiac findings at necropsy in patients with chronic kidney disease maintained on chronic hemodialysis

Studies of multiple hearts at necropsy are lacking in patients who have been on chronic hemodialysis for chronic kidney disease (CKD). We studied at necropsy 120 patients who had been treated with hemodialysis for more than 1 year (mean, 5.25 ± 4.33 yr). Their ages ranged from 24 to 81 years (mean, 53 yr); 91 (76%) were men. Calcific deposits were present in the heart at necropsy in 74 (62%) patients: in the epicardial coronary arteries in all 74 (62%); in the mitral annular region in 52 (42%) patients, and in the aortic valve cusps in 42 (35%) patients. The frequency and quantity of the cardiac calcific deposits were significantly greater in the older compared with the younger patients, and in those with longer durations of hemodialysis compared with those with shorter durations. Despite the calcific deposits, which were sometimes huge, only 47 (39%) patients had 1 or more coronary arteries narrowed more than 75% in cross-sectional area by atherosclerotic plaques, apparently no patient had clinical evidence of mitral stenosis, and 9 patients had clinical evidence of aortic valve stenosis. Thus, we found that CKD treated with hemodialysis is a major producer of cardiac calcific deposits, some of which can be massive. Only a minority of the calcific deposits, however, appeared to lead to cardiac dysfunction or myocardial ischemia during life.

Diagnosis and treatment of coronary artery disease in hemodialysis patients evaluated for transplant

We present a review of current strategies for the diagnosis and treatment of coronary artery disease (CAD) in patients with advanced chronic kidney disease who are on the waiting list for transplants, based on data from the literature and originated from a single-center cohort of 1,250 patients with maximum follow-up of 12 years. We discuss the best way to select patients to be tested for CAD, how to choose the more adequate screening test for CAD and cardiovascular disease, how to select patients for invasive treatment studies and how to treat patients with significant CAD. We also suggest new research avenues to be explored to resolve some problems in this area.

Effect of changes in the intravascular volume during hemodialysis on blood viscoelasticity

Adoption of high rate of ultrafiltration (UF) during hemodialysis (HD) may affect the hemorhelogical blood profile, by changing Hematocrit (Hct) and the concentration of plasma proteins, which may in turn interfere with tissue perfusion. The aim of this work is to examine the effect of acute volume change during dialysis on the hemorheological variables. The study included 21 hemodialysis patients. Hematocrit (Hct) and percent decrease in blood volume (BV) were recorded by blood volume monitor. Blood samples were taken before and at the end of dialysis, for measuring plasma fibrinogen and haemorheological variables, which included blood viscosity, plasma viscosity, red cells elasticity and aggregation. The UF volume was 3.52±1.54 L. Hct increased from 34.2±6.1 to 42.1±7.3% (P<0.001), and blood volume (BV) decreased to 85.5±6.4% (P<0.001). Blood and plasma viscosity significantly increased from 3.28±0.69 to 5.48±0.85 mPa.s (P<0.001), and from 1.24 ± 0.16 to 1.65±0.24 mPa.s (P<0.001), respectively. Changes in plasma viscosity were correlated to changes in plasma fibrinogen (r=0.63, P<0.05), while the increase in blood viscosity was correlated to the percent reduction in blood volume (r=0.85, P<0.005). Red cells elasticity increased from 0.26±0.12 to 0.48±0.18 mPa.s (P<0.05), and the aggregation index rose from 0.86±0.31 to 1.25±0.26 (P<0.01). This combination of increased plasma viscosity and red cell aggregability may lower the velocity of erythrocyte transfer inside the tissue capillaries after HD, which may affect tissue perfusion. Moreover, increased elasticity may require more energy from the heart to disaggregate the cells, and this may induce problems in the patients with cardiac dysfunction. In conclusion, the hemorheological variables change after dialysis in the direction which may impede the flow inside the microvessels.

Should we screen for coronary artery disease in asymptomatic chronic dialysis patients?

The hemodialysis population is characterized by a high prevalence of 'asymptomatic' coronary artery disease (CAD), which should be interpreted differently from asymptomatic disease in the general population. A hemodynamically significant stenosis may not become clinically apparent owing to impaired exercise tolerance and autonomic neuropathy. The continuous presence of silent ischemia may cause heart failure, arrhythmias, and sudden death. Whether revascularization of an asymptomatic dialysis patient improves outcome remains a moot point, although several observational studies and one small RCT suggest a benefit. It can therefore be defended to screen asymptomatic dialysis patients for CAD. A number of noninvasive screening tests are available, but none has proved equally practical and reliable in the dialysis population as in the general population. Myocardial perfusion scintigraphy (MPS) before and after a pharmacological stress such as dipyridamole can reveal both ischemia and myocardial scarring. When compared with coronary angiography, low sensitivities were reported and attributed to impaired vasodilation to dipyridamole in dialysis patients. A more likely explanation is that not every anatomical stenosis will lead to impaired coronary blood flow on MPS. Numerous studies have shown an incremental prognostic value of dipyridamole-MPS over clinical data for prediction of adverse cardiac events, in some studies even over coronary angiography. Pending the availability of high-quality evidence, in our opinion asymptomatic dialysis patients could undergo dipyridamole-MPS, followed by coronary angiography in case of an abnormal scan. This combined physiological and anatomical evaluation of the coronary circulation allows us to determine which coronary stenosis is clinically relevant and therefore should be revascularized.

Coronary risk assessment and management options in chronic kidney disease patients prior to kidney transplantation

Cardiovascular disease remains the most important cause of morbidity and mortality among kidney transplant recipients. Nearly half the deaths in transplanted patients are attributed to cardiac causes and almost 5% of these deaths occur within the first year after transplantation. The ideal strategies to screen for coronary artery disease (CAD) in chronic kidney disease patients who are evaluated for kidney transplantation (KT) remain controversial. The American Society of Transplantation recommends that patients with diabetes, prior history of ischemic heart disease or an abnormal ECG, or age ≥50 years should be considered as high-risk for CAD and referred for a cardiac stress test and only those with a positive stress test, for coronary angiography. Despite these recommendations, vast variations exist in the way these patients are screened for CAD at different transplant centers. The sensitivity and specificity of noninvasive cardiac tests in CKD patients is much lower than that in the general population. This has prompted the use of direct diagnostic cardiac catheterization in high-risk patients in several transplant centers despite the risks associated with this invasive procedure. No large randomized controlled trials exist to date that address these issues. In this article, we review the existing literature with regards to the available data on cardiovascular risk screening and management options in CKD patients presenting for kidney transplantation and outline a strategy for approach to these patients.

Does uremia cause vascular dysfunction?

Vascular dysfunction induced by uremia has 4 main aspects. (1) Atherosclerosis is increased. Intima-media thickness is increased, and animal studies have established that uremia accelerates atherosclerosis. Uremic toxins are involved in several steps of atherosclerosis. Leukocyte activation is stimulated by guanidines, advanced glycation end products (AGE), p-cresyl sulfate, platelet diadenosine polyphosphates, and indoxyl sulfate. Endothelial adhesion molecules are stimulated by indoxyl sulfate. Migration and proliferation of vascular smooth muscle cells (VSMC) are stimulated by local inflammation which could be triggered by indoxyl sulfate and AGE. Uremia is associated with an increase in von Willebrand factor, thrombomodulin, plasminogen activator inhibitor 1, and matrix metalloproteinases. These factors contribute to thrombosis and plaque destabilization. There is also a decrease in nitric oxide (NO) availability, due to asymmetric dimethylarginine (ADMA), AGE, and oxidative stress. Moreover, circulating endothelial microparticles (EMP) are increased in uremia, and inhibit the NO pathway. EMP are induced in vitro by indoxyl sulfate and p-cresyl sulfate. (2) Arterial stiffness occurs due to the loss of compliance of the vascular wall which induces an increase in pulse pressure leading to left ventricular hypertrophy and a decrease in coronary perfusion. Implicated uremic toxins are ADMA, AGE, and oxidative stress. (3) Vascular calcifications are increased in uremia. Their formation involves a transdifferentiation process of VSMC into osteoblast-like cells. Implicated uremic toxins are mainly inorganic phosphate, as well as reactive oxygen species, tumor necrosis factor and leptin. (4) Abnormalities of vascular repair and neointimal hyperplasia are due to VSMC proliferation and lead to severe reduction of vascular lumen. Restenosis after coronary angioplasty is higher in dialysis than in nondialysis patients. Arteriovenous fistula stenosis is the most common cause of thrombosis. Uremic toxins such as indoxyl sulfate and some guanidine compounds inhibit endothelial proliferation and wound repair. Endothelial progenitor cells which contribute to vessel repair are decreased and impaired in uremia, related to high serum levels of β(2)-microglobulin and indole-3 acetic acid. Overall, there is a link between kidney function and cardiovascular risk, as emphasized by recent meta-analyses. Moreover, an association has been reported between cardiovascular mortality and uremic toxins such as indoxyl sulfate, p-cresol and p-cresyl sulfate.

Atherosclerosis in CKD: differences from the general population

The prevalence of cardiovascular morbidity and mortality is higher in patients with chronic kidney disease (CKD)-especially those with end-stage renal disease-than in the general population. The contribution of atherosclerosis to cardiovascular disease in patients with CKD remains unclear. Researchers in the 1970s proposed that atherosclerosis was the main cause of cardiovascular disease in patients with CKD and that its progression, based on observations of patients on long-term dialysis, was accelerated by the uremic state. Subsequent reports, however, favor the involvement of other mechanisms, such as arteriosclerosis (characterized by vascular stiffening), vascular calcification, 'myocyte/capillary mismatch', congestive cardiomyopathy, and sudden cardiac death. Imaging and morphological studies have contributed to our understanding of the pathogenesis and progression of cardiovascular disease associated with CKD. Based on clinical and experimental findings, we hypothesize the following: the initial cardiovascular abnormalities in the CKD setting include arteriosclerosis, left ventricular diastolic dysfunction, and left ventricular hypertrophy, abnormalities which, in adult patients, are often accompanied by atherosclerosis. The prevalence of atherosclerosis increases with age and is aggravated, but not specifically induced, by CKD. The cardiovascular events associated with atherosclerosis are more often fatal in patients with CKD than in individuals without CKD.

Uremic cardiomyopathy and insulin resistance: a critical role for akt?

Uremic cardiomyopathy is a classic complication of chronic renal failure whose cause is unclear and treatment remains disappointing. Insulin resistance is an independent predictor of cardiovascular mortality in chronic renal failure. Underlying insulin resistance are defects in insulin signaling through the protein kinase, Akt. Akt acts as a nodal point in the control of both the metabolic and pleiotropic effects of insulin. Imbalance among these effects leads to cardiac hypertrophy, fibrosis, and apoptosis; less angiogenesis; metabolic remodeling; and altered calcium cycling, all key features of uremic cardiomyopathy. Here we consider the role of Akt in the development of uremic cardiomyopathy, drawing parallels from models of hypertrophic cardiac disease.

Perioperative management of patients with renal disease

The patient who has renal disease is susceptible to many potential complications during the perioperative period. The prevention of postoperative acute renal failure (ARF), especially in patients who have existing chronic kidney disease, and management of patients who have end-stage renal disease (ESRD) who are undergoing surgery are challenging. Elimination of risk factors for ARF and early diagnosis of ARF should improve patient outcomes. For patients who have ESRD, a thorough and comprehensive evaluation is necessary to decrease morbidity and mortality associated with the end-organ damage. This article reviews the prevention of postoperative ARF and the perioperative management of patients who have ESRD who are undergoing surgery.

Real-time three-dimensional echocardiography provides advanced haemodynamic information associated with intra-dialytic hypotension in patients with autonomic dysfunction

BACKGROUND

Real-time three-dimensional echocardiography (RT3DE) has emerged as a more accurate and effective tool for assessing left ventricular (LV) function, compared to traditional two-dimensional (2D) methods. In this study, we used this new tool to revise the controversial relationship between LV function and intra-dialytic hypotension.

METHODS

This study enrolled 29 intra-dialytic hypotensive patients (the IDH group) and 34 controls (the CON group) on regular maintenance haemodialysis. The RT3DE- and 2D-derived ejection fraction (EF), stroke volume index (SVI) and ratio of early transmitral inflow velocity to diastolic early tissue velocity were assessed at pre-dialysis and mid-dialysis. The intravascular volume was assessed by the inferior vena cava collapsibility index.

RESULTS

Pre-dialysis evaluation showed no difference in RT3DE- and 2D-derived parameters between the two groups. At mid-dialysis, the IDH group had a lower 2D EF (54 +/- 9.1 versus 62 +/- 6.8% in the CON group, P < 0.001), RT3DE EF (53 +/- 6 versus 60 +/- 7% in the CON group, P < 0.001) and SVI (24.3 +/- 8 versus 30.6 +/- 12.2 mL in the CON group, P = 0.02). From pre-dialysis to mid-dialysis, the IDH group had greater decrease in the change in 2D EF (-4.8% +/- 12.6% versus 5% +/- 13.7% in the CON group, P = 0.004), RT3DE EF (-11.8 +/- 10.3 versus -3.4 +/- 11.5% in the CON group, P = 0.003) and SVI (-17.3 +/- 18.5 versus -9.2 +/- 19.8% in the CON group, P = 0.004). The calculated cardiac index change also showed a greater decrease in the IDH group (-17.8 +/- 20.2 versus -5.7 +/- 18.5% in the CON group, P = 0.02). No significant difference in the ratio of early transmitral inflow velocity to diastolic early tissue velocity, heart rate, systemic vascular resistance index or inferior vena cava collapsibility index was found between the two groups at the baseline or mid-dialysis. A lack of an increase in heart rate and the systemic vascular resistance index in the IDH group during the hypotensive episodes implies that these patients have autonomic dysfunction. Multivariate analysis showed that the RT3DE EF change of < -9.5% (odds ratio = 6, P = 0.003) and the presence of diabetes (odds ratio = 4.4, P = 0.013) had significant and independent associations with intra-dialytic hypotension.

CONCLUSIONS

By adopting RT3DE to assess LV performance, our data demonstrated that an inadequate compensation in the LV systolic function is the main mechanism mediating the occurrence of intra-dialytic hypotension in patients with autonomic dysfunction.