The clinical course of left ventricular hypertrophy in dialysis patients

Severe Left Ventricular Outflow Tract Obstruction Following Arteriovenous Fistula Reopening in a Dialysis Patient With Left Ventricular Hypertrophy

Arteriovenous fistulas (AVFs) are the preferred vascular access for hemodialysis due to their durability and lower risk of complications than alternative access methods. However, AVFs can significantly impact cardiac function, particularly in patients with preexisting cardiovascular conditions. We present a case of a 56-year-old female with a history of hypertension and end-stage renal disease who developed recurrent hypotension, dizziness, and dyspnea following AVF reopening. The echocardiographic evaluation revealed severe left ventricular hypertrophy, systolic anterior motion of the mitral valve, significant mitral regurgitation, and left ventricular outflow tract (LVOT) obstruction with a high-pressure gradient. Despite medical management with beta-blockers, symptoms persisted, leading to the decision to close the AVF surgically. Following AVF closure, echocardiography showed a marked improvement in mitral regurgitation and resolution of LVOT obstruction, with the patient tolerating subsequent dialysis without complications. This case highlights the potential hemodynamic consequences of AVF reopening in patients with underlying cardiac pathology and emphasizes the need for careful cardiovascular evaluation.

Aortic arch calcification increases major adverse cardiac event risk, modifiable by echocardiographic left ventricular hypertrophy, in end-stage kidney disease patients

Background

The factors affecting cardiovascular risk associated with vascular calcification in patients with chronic kidney disease are less well addressed. Distinct risk factors may contribute synergistically to this elevated cardiovascular risk in this population.

Objectives

We aimed to determine whether echocardiographic left ventricular hypertrophy (LVH) affects the risk of major adverse cardiac events (MACE) associated with vascular calcification in end-stage kidney disease (ESKD) patients.

Methods

In this retrospective cohort study, ESKD patients underwent chest radiography and echocardiography to assess aortic arch calcification (AoAC) and LVH, respectively, and were classified into three groups accordingly: non-to-mild AoAC without LVH, non-to-mild AoAC with LVH, and moderate-to-severe AoAC. The risks of MACE, cardiovascular mortality, and overall mortality were assessed using Cox proportional hazard analysis.

Results

Of the 283 enrolled ESKD patients, 44 (15.5%) had non-to-mild AoAC without LVH, 117 (41.3%) had non-to-mild AoAC with LVH, and 122 (43.1%) had moderate-to-severe AoAC. After 34.1 months, 107 (37.8%) participants developed MACE, including 6 (13.6%), 40 (34.2%), and 61 (50%) from each respective group. Those with moderate-to-severe AoAC (Hazard ratio, 3.72; 95% confidence interval, 1.58-8.73) had a significantly higher risk of MACE than did those with non-to-mild AoAC without LVH or with non-to-mild AoAC and LVH (Hazard ratio, 2.73; 95% confidence interval, 1.16-6.46). A similar trend was observed for cardiovascular and overall mortality.

Conclusion

Echocardiographic LVH could modify the risk of adverse cardiovascular events associated with vascular calcification in ESKD patients. Interventions aiming to ameliorate both morbidities might be translated into a lower MACE risk in this population.

Hypertension and cardiomyopathy associated with chronic kidney disease: epidemiology, pathogenesis and treatment considerations

Chronic kidney disease (CKD) is a complex condition with a prevalence of 10-15% worldwide. An inverse-graded relationship exists between cardiovascular events and mortality with kidney function which is independent of age, sex, and other risk factors. The proportion of deaths due to heart failure and sudden cardiac death increase with progression of chronic kidney disease with relatively fewer deaths from atheromatous, vasculo-occlusive processes. This phenomenon can largely be explained by the increased prevalence of CKD-associated cardiomyopathy with worsening kidney function. The key features of CKD-associated cardiomyopathy are increased left ventricular mass and left ventricular hypertrophy, diastolic and systolic left ventricular dysfunction, and profound cardiac fibrosis on histology. While these features have predominantly been described in patients with advanced kidney disease on dialysis treatment, patients with only mild to moderate renal impairment already exhibit structural and functional changes consistent with CKD-associated cardiomyopathy. In this review we discuss the key drivers of CKD-associated cardiomyopathy and the key role of hypertension in its pathogenesis. We also evaluate existing, as well as developing therapies in the treatment of CKD-associated cardiomyopathy.

Aspirin to target arterial events in chronic kidney disease (ATTACK): study protocol for a multicentre, prospective, randomised, open-label, blinded endpoint, parallel group trial of low-dose aspirin vs. standard care for the primary prevention of cardiovascular disease in people with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a very common long-term condition and powerful risk factor for cardiovascular disease (CVD). Low-dose aspirin is of proven benefit in the secondary prevention of myocardial infarction (MI) and stroke in people with pre-existing CVD. However, in people without CVD, the rates of MI and stroke are much lower, and the benefits of aspirin in the primary prevention of CVD are largely balanced by an increased risk of bleeding. People with CKD are at greatly increased risk of CVD and so the absolute benefits of aspirin are likely to be greater than in lower-risk groups, even if the relative benefits are the same. Post hoc evidence suggests the relative benefits may be greater in the CKD population but the risk of bleeding may also be higher. A definitive study of aspirin for primary prevention in this high-risk group, recommended by the National Institute for Health and Care Excellence (NICE) in 2014, has never been conducted. The question has global significance given the rising burden of CKD worldwide and the low cost of aspirin.

METHODS

ATTACK is a pragmatic multicentre, prospective, randomised, open-label, blinded endpoint adjudication superiority trial of aspirin 75 mg daily vs. standard care for the primary prevention of CVD in 25,210 people aged 18 years and over with CKD recruited from UK Primary Care. Participants aged 18 years and over with CKD (GFR category G1-G4) will be identified in Primary Care and followed up using routinely collected data and annual questionnaires for an average of 5 years. The primary outcome is the time to first major vascular event (composite of non-fatal MI, non-fatal stroke and cardiovascular death [excluding confirmed intracranial haemorrhage and other fatal cardiovascular haemorrhage]). Deaths from other causes (including fatal bleeding) will be treated as competing events. The study will continue until 1827 major vascular events have occurred. The principal safety outcome is major intracranial and extracranial bleeding; this is hypothesised to be increased in those randomised to take aspirin. The key consideration is then whether and to what extent the benefits of aspirin from the expected reduction in CVD events exceed the risks of major bleeding.

DISCUSSION

This will be the first definitive trial of aspirin for primary CVD prevention in CKD patients. The research will be of great interest to clinicians, guideline groups and policy-makers, in the UK and globally, particularly given the high and rising prevalence of CKD that is driven by population ageing and epidemics of obesity and diabetes. The low cost of aspirin means that a positive result would be of relevance to low- and middle-income countries and the impact in the developed world less diluted by any inequalities in health care access.

TRIAL REGISTRATION

ISRCTN: ISRCTN40920200 . EudraCT: 2018-000644-26 .

CLINICALTRIALS

gov: NCT03796156.

Marinobufagenin, left ventricular geometry and cardiac dysfunction in end-stage kidney disease patients

PURPOSE

Left ventricular hypertrophy (LVH) is remarkably prevalent among end-stage kidney disease (ESKD) on chronic dialysis and has a strong prognostic value for adverse outcomes. In experimental models, the endogenous cardiotonic steroid Marinobufagenin (MBG) promotes cardiac hypertrophy and accelerates uremic cardiomyopathy. In this study, we investigated the possible relationships between MBG, LV geometry and cardiac dysfunction in a clinical setting of ESKD.

METHODS

Plasmatic MBG was measured in 46 prevalent ESKD patients (n = 30 HD, n = 16 PD) together with a thorough laboratory, clinical, bioimpedance and echocardiography assessment. Different patterns of LV geometry were defined by left ventricular mass index (LVMi) and ventricular morphology. Diastolic dysfunction was diagnosed by the ASE/EACVI criteria.

RESULTS

MBG levels were significantly higher in ESKD patients than in healthy controls (p = 0.001) and more elevated in PD than in HD (p = 0.02). At multivariate analyses, E/e' (β = 0.38; p = 0.009) and LVMi (β = 0.42; p = 0.02) remained the sole independent predictors of MBG. A statistically significant trend in MBG levels (p = 0.01) was noticed across different patterns of LV geometry, with the highest values found in eccentric LVH. MBG levels were higher in the presence of diastolic dysfunction (p = 0.01) and this substance displayed a remarkable diagnostic capacity in distinguish patients with normal LV geometry, LV hypertrophy and, particularly, eccentric LVH (AUC 0.888; p < 0.0001) and diastolic dysfunction (AUC 0.79; p = 0.001).

CONCLUSIONS

Deranged plasma MBG levels in ESKD patients on chronic dialysis reflect alterations in LV structure and function. MBG may, thus, candidate as a novel biomarker for improving cardiac assessment in this high-risk population.

MicroRNA-30 regulates left ventricular hypertrophy in chronic kidney disease

Left ventricular hypertrophy (LVH) is a primary feature of cardiovascular complications in patients with chronic kidney disease (CKD). miRNA-30 is an important posttranscriptional regulator of LVH, but it is unknown whether miRNA-30 participates in the process of CKD-induced LVH. In the present study, we found that CKD not only resulted in LVH but also suppressed miRNA-30 expression in the myocardium. Rescue of cardiomyocyte-specific miRNA-30 attenuated LVH in CKD rats without altering CKD progression. Importantly, in vivo and in vitro knockdown of miRNA-30 in cardiomyocytes led to cardiomyocyte hypertrophy by upregulating the calcineurin signaling directly. Furthermore, CKD-related detrimental factors, such as fibroblast growth factor-23, uremic toxin, angiotensin II, and transforming growth factor–β, suppressed cardiac miRNA-30 expression, while miRNA-30 supplementation blunted cardiomyocyte hypertrophy induced by such factors. These results uncover a potentially novel mechanism of CKD-induced LVH and provide a potential therapeutic target for CKD patients with LVH.

Downregulation of myocardial miRNA-30 is involved in chronic kidney disease–induced left ventricular hypertrophy, whereas exogenous miRNA-30 rescue inhibits this process.

Translational Sciences in Cardiac Failure Secondary to Arteriovenous Fistula in Hemodialysis Patients

High-output cardiac failure is a rare form of heart failure associated with the formation of arteriovenous fistula (AVF) in hemodialysis patients. The pathophysiology underlying the HOCF is complex and multifactorial. Presence of AVF can cause long term hemodynamic changes that ultimately lead to increased cardiac output and consequently cardiac failure. A number of risk factors have been associated with the development of HOCF post-AVF construction, including male sex, a proximally located AVF and a state of volume overload. Dysregulation of tissue inhibitor of matrix metalloproteinase 4, Sirtuin-1 and Sirtuin-3 gene expression have been associated with the development of heart failure. The differences observed between genders have been attributed to altered activity of the β-adrenoceptor system. Numerous biomarkers including cardiac troponin T and I, atrial natriuretic peptide, brain natriuretic peptide among others have shown both prognostic and diagnostic potential; however further research is needed to establish their utility in clinical practice for patients with AVF associated HOCF. In recent years risk stratification models have been developed to help identify patients at the highest risk of developing HOCF post AVF which could be revolutionary in its identification and management. Potential options for managing HOCF post-AVF include AVF ligation, banding and anastoplasty however these procedures are not without their own associated risks. In this review, we discuss the pathophysiology, risk stratification and management of patients with AVF associated HOCF.

Perioperative Anesthetic Management and Clinical Outcomes in Patients Undergoing Coronary Artery Bypass Grafting and Kidney Transplant in the Same Session

BACKGROUND

Cardiovascular disease is commonly seen in patients with end-stage renal disease (ESRD) and is a major cause of graft failure and death in patients undergoing kidney transplant.

METHODS

The retrospective study included 77 patients with ESRD who underwent combined coronary artery bypass grafting (CABG) and kidney transplant between May 2010 and September 2017.

RESULTS

The patients included 65 (84.4%) men and 12 (15.6%) women. Diabetes mellitus (DM) and hypertension (HT) were present in 71.4% and 90.9% of the patients, respectively. Mean postoperative intensive care unit (ICU) stay was 3.4 ± 1.6 days, mean time to extubation was 12.1 ± 3.7 hours, and mean hospital stay was 11.6 ± 3.5 days. In the small group with graft rejection, EF was 41.1 ± 12.3. Two patients underwent second kidney transplant, and 1 patient underwent a third kidney transplant. Mean amount of red blood cells (RBC) and fresh-frozen plasma (FFP) transfusion was 2.6 ± 0.7 and 2.1 ± 0.7 units, respectively.

CONCLUSION

The study showed that CABG and kidney transplant can be performed in a combined approach in the same session and that this combined approach is likely to have a more favorable effect on mortality and morbidity compared to the administration of these 2 surgeries in separate sessions.

Major and Minor Risk Factors for Cardiovascular Disease in Continuous Ambulatory Peritoneal Dialysis Patients

Uremia in general and peritoneal dialysis in particular bring with them risk factors for the development of cardiovascular disease. These factors include multiple lipid abnormalities, hyperhomocysteinemia, abdominal obesity, chronic inflammation, hypoalbuminemia, oxidative stress, and AGE formation. When these are combined with conventional risk factors, one can appreciate why the incidence of cardiovascular disease is so high in peritoneal dialysis patients. Treatment strategies should address each of these risks appropriately.

Cardiovascular Disease in Peritoneal Dialysis

Cardiovascular morbidity and mortality remain high in ESRD patients. Lipid abnormalities in CAPD may be more important than in hemodialysis. Vessel calcification may have a role in atherosclerotic heart disease, but this is only an inference from several clinical observations, and it remains to be defined more clearly as a risk factor. Left ventricular hypertrophy is frequent in this patient population, and is associated with specific clinical patterns and an in creased risk of death. Erythropoietin treatment of anemia and tight blood pressure controls have proved to help in reversing severe left ventricular hypertrophy. Finally, we describe a syndrome of the hypertrophic, high cardiac output hemodialysis heart, which is characterized by a high cardiac output in hemodialysis patients. It is associated with left ventricular hypertrophy and eventually right ventricular hypertrophy with tricuspid insufficiency. This may require fistula revision and even a switch to peritoneal dialysis.

Impact of Dialysis Adequacy on Cardiac Function in Pediatric CAPD Patients

Background

Left ventricular hypertrophy is a major cause of morbidity and mortality among patients with chronic renal failure. Uremia-related risk factors play a fundamental role in its occurrence, thus better prognosis and prolonged survival can be attained by successful dialytic therapies.

Objective

To investigate whether dialysis adequacy has a beneficial effect on cardiac structure and function in children receiving continuous ambulatory peritoneal dialysis (CAPD).

Design

Cross-sectional study in the Pediatric Peritoneal Dialysis Unit of a university hospital.

Patients

Eighteen children, aged 13.3 ± 2.8 years, being treated with CAPD, and 20 healthy age- and sex-matched control subjects were enrolled in this study.

Main Outcome Measures

Echocardiographic evaluation was performed in all subjects. Dialysis adequacy indices [weekly urea (Kt/V) and creatinine clearance (TCCr)] were calculated in the dialysis group.

Results

Interventricular septal thickness, left ventricular (LV) posterior wall thickness, LV mass index (LVMI), and LV end systolic and diastolic dimensions were all found to be significantly higher in the CAPD group compared to the control subjects ( p < 0.01). Ejection fraction and fractional shortening of the LV were not significantly different between the two groups. Mean Kt/V was 2.02 ± 0.71 and mean TCCr was 58 ± 33 L/wk/1.73 m2. There were significant negative correlations between dialysis adequacy indices and LV end systolic and diastolic dimensions ( p < 0.05 and p < 0.001). Ejection fraction and fractional shortening were positively correlated with Kt/V ( p < 0.01). Systolic and diastolic blood pressures were positively correlated with LVMI ( r = 0.501 and r = 0.523). Significant inverse correlations between mean arterial pressure and both Kt/V and TCCr ( r = -0.555 and r = -0.520) were detected.

Conclusion

These data clearly document that cardiac structure and function are remarkably influenced by the uremic state and dialysis therapy in pediatric CAPD patients. The close relationships between echocardiographic findings and dialysis adequacy indices suggest that adequate dialysis has a beneficial effect on cardiac function via effective removal of toxic substances.

αKlotho attenuates cardiac hypertrophy and increases myocardial fibroblast growth factor 21 expression in uremic rats

In chronic kidney disease (CKD), evidence suggests that soluble αKlotho (sKlotho) has cardioprotective effects. Contrariwise, high circulating levels of fibroblast growth factor 23 (FGF23) are related to uremic cardiomyopathy development. Recently, it has been demonstrated that sKlotho can act as a soluble FGF23 co-receptor, allowing sKlotho to modulate FGF23 actions in the myocardium, leading to the activation of cardioprotective pathways. Fibroblast growth factor 21 (FGF21) is a cardiomyokine with sKlotho-like protective actions and has never been evaluated in uremic cardiomyopathy. Here, we aimed to evaluate whether recombinant αKlotho (rKlotho) replacement can attenuate cardiac remodeling in an established uremic cardiomyopathy, and to explore its impact on myocardial FGF21 expression. Forty-six male Wistar rats were divided into three groups: control, CKD-untreated, and CKD treated with rKlotho (CKD + KL). CKD was induced by 5/6 nephrectomy. From weeks 4–8, the control and CKD-untreated groups received vehicle, whereas the CKD + KL group received subcutaneous rKlotho replacement (0.01 mg/kg) every 48 h. Myocardial remodeling was evaluated by heart weight/tibia length (HW/TL) ratio, echocardiographic parameters, myocardial histomorphometry, and myocardial expression of β-myosin heavy chain (MHCβ), alpha smooth muscle actin (αSMA), transient receptor potential cation channel 6 (TRPC6), and FGF21. As expected, CKD animals had reduced levels of sKlotho and increased serum FGF23 levels. Compared to the control group, manifest myocardial remodeling was present in the CKD-untreated group, while it was attenuated in the CKD + KL group. Furthermore, cardiomyocyte diameter and interstitial fibrotic area were reduced in the CKD + KL group compared to the CKD-untreated group. Similarly, rKlotho replacement was associated with reduced myocardial expression of TRPC6, MHCβ, and αSMA and a higher expression of FGF21. rKlotho showed cardioprotective effects by attenuating myocardial remodeling and reducing TRPC6 expression. Interestingly, rKlotho replacement was also associated with increased myocardial FGF21 expression, suggesting that an interaction between the two cardioprotective pathways needs to be further explored.

Impact statement

This study aimed to evaluate whether rKlotho replacement can attenuate cardiac remodeling in a post-disease onset therapeutic reasoning and explore the impact on myocardial FGF21 expression. This study contributes significantly to the literature, as the therapeutic effects of rKlotho replacement and FGF21 myocardial expression have not been widely evaluated in a setting of uremic cardiomyopathy. For the first time, it has been demonstrated that subcutaneous rKlotho replacement may attenuate cardiac remodeling in established uremic cardiomyopathy and increase myocardial expression of FGF21, suggesting a correlation between αKlotho and myocardial FGF21 expression. The possibility of interaction between the αKlotho and FGF21 cardioprotective pathways needs to be further explored, but, if confirmed, would point to a therapeutic potential of FGF21 in uremic cardiomyopathy.

Impact of Arteriovenous Fistula on Cardiac Size and Function in Kidney Transplant Recipients: A Retrospective Evaluation of 5-Year Echocardiographic Outcome

OBJECTIVES

The effect of a functioning arteriovenous fistula on cardiac function in kidney transplant recipients has not been thoroughly investigated.

MATERIALS AND METHODS

We retrospectively evaluated cardiac function in 99 renal transplant recipients using transthoracic echocardiography, with available follow-up at baseline and 2 and 5 years posttransplant. Patients were divided into 2 groups: a control group (n = 47) with no functioning arteriovenous fistula immediately after transplant and an arteriovenous fistula group (n = 52) with a functioning arteriovenous fistula for at least 5 years after transplant. Left ventricular ejection fraction, diastolic thickness of the interventricular septum, and left ventricular end-diastolic diameter were assessed.

RESULTS

In our study, patients (62.6% men, 7.1% with diabetes, mean age of 55.6 ± 11.5 years), we observed no significant differences with respect to baseline left ventricular ejection fraction and interventricular septum; however, in the arteriovenous fistula group, baseline left ventricular end-diastolic diameter was marginally higher than that shown in the control group (50.6 ± 5.4 vs 48.6 ± 4.4 mm; P = .054). In multivariate analysis, functioning fistula and peripheral arterial disease were negatively associated with left ventricular ejection fraction at 5 years posttransplant, whereas baseline left ventricular ejection fraction had a minimal positive effect: B (95% confidence interval) of -2.186 (-4.312 to -0.061) (P = .044), -5.304 (-9.686 to -0.922) (P = .018), and 0.247 (0.047 to 0.446) (P = .016), respectively. Functioning fistula also emerged as associated with larger left ventricular end-diastolic diameter at 2 and 5 years posttransplant: B (95% confidence interval) of 3.047 (1.470-4.625) (P < .001) and 2.122 (0.406-3.838) (P = .016), respectively.

CONCLUSIONS

Maintenance of a functioning fistula in kidney transplant recipients may be associated with adverse long-term effects on left ventricular ejection fraction and left ventricular end-diastolic diameter.

Interrelationship Between Kidney Function and Percutaneous Mitral Valve Interventions: A Comprehensive Review

Percutaneous mitral valve repair is emerging as a reasonable alternative especially in those with an unfavorable surgical risk profile in the repair of mitral regurgitation. At this time, our understanding of the effects of underlying renal dysfunction on outcomes with percutaneous mitral valve repair and the effects of this procedure itself on renal function is evolving, as more data emerges in this field. The current evidence suggests that the correction of mitral regurgitation via percutaneous mitral valve repair is associated with some degree of improvement in cardiac function, hemodynamics and renal function. The improvement in renal function was more significant for those with greater renal dysfunction at baseline. The presence of Chronic Kidney Disease (CKD) in turn has been associated with poor long-term outcomes including increased mortality and hospitalization among patients who undergo percutaneous mitral valve repair. This was true regardless of the degree of improvement in GFR post repair advanced CKD. The adverse impact of CKD on long-term outcomes was consistent across all studies and was more prominent in those with GFR<30 mL/min/1.73 m². It is clear that from these contrasting evidences of improved renal function post mitral valve repair but poor long-term outcomes including increased mortality in patients with CKD, that proper patient selection for percutaneous mitral valve repair is key. There is a need to have better-standardized criteria for patients who should qualify to have percutaneous mitral valve replacement with Mitraclip. In this new era of percutaneous mitral valve repair, much work needs to be done to optimize long-term patient outcomes.

Uremic Cardiomyopathy: A New Piece in the Chronic Kidney Disease-Mineral and Bone Disorder Puzzle

Cardiovascular diseases are the main cause of death in chronic kidney disease (CKD) patients. In dialysis patients, sudden cardiac death accounts for 40% of all deaths. In these patients, sudden cardiac death is usually secondary to an underlying cardiomyopathy, which is clinically identified by the high prevalence of left ventricular hypertrophy and the resultant mechanical and electrical dysfunction. CKD-related cardiomyopathy has a multifactorial pathophysiology. Recent evidence has highlighted the central pathophysiological role of chronic kidney disease-mineral and bone disorder (CKD-MBD) with hyperphosphatemia and high fibroblast growth factor 23 (FGF23) levels in these patients. Further, since CKD is known to be an αKlotho deficiency state, experimental studies have demonstrated that the deleterious effects of FGF23 can be minimized by reestablishing adequate soluble Klotho levels. Herein, we present a review that addresses not only the development of the understanding of CKD-related cardiomyopathy pathophysiology, but also explores the recent data that identify the triad of hyperphosphatemia, high FGF23 levels and αKlotho deficiency as playing a central role on it. Taken together, the data suggest that the uremic cardiomyopathy can be considered a new piece in the CKD-DMO puzzle.

The occurrence of atrial fibrillation in dialysis patients and its association with left atrium volume before and after dialysis

PURPOSE

Atrial fibrillation is a serious problem, especially in patients on dialysis. The prevalence of AF in this group of patients is higher than in general population and associated with increased mortality. The aim of this study was to assess the risk of the occurrence of atrial fibrillation related to intradialysis hypotension and left atrium volume enlargement associated with dialysis. The influence of dialysis session on: E/E', V LA, E/A, E', V RA and the width of inferior vena cava of RV was analyzed.

METHODS

This study included 40 patients on hemodialysis. Echocardiographic examination was performed to assess heart condition and function, the presence of LVH and systolic and diastolic function disturbances, LV mass, LA size, LAV, RAV, E/A, E', E/E, ejection fraction in all patients before and after dialysis. Moreover, all patients had ECG Holter continuously recording heart's rhythm before and after dialysis to assess the occurrence of atrial fibrillation related to dialysis session.

RESULTS

The analysis of differences in echocardiographic parameters before and after dialysis demonstrated significantly greater left atrium volume, right atrium volume, width of inferior vena cava and e' parameter before dialysis in comparison with post-dialysis state. Significantly higher incidence of AF after dialysis was seen. Volume of left atrium exceeding 32 mm (cutoff value) was observed significantly more often in patients before dialysis. No association was observed between left ventricle mass and left atrium volume.

CONCLUSIONS

The dialysis procedure may be a trigger for atrial fibrillation and thus AF preventive measures should be introduced in dialysis patients.

Increased serum renalase in hemodialysis patients: is it related to left ventricular hypertrophy?

INTRODUCTION

Left ventricular hypertrophy (LVH) is one of the most common cardiac abnormalities in patients with end stage renal disease (ESRD). Hypertension, diabetes, increased body mass index, gender, age, anemia, and hyperparathyroidism have been described as risk factors for LVH in patients on dialysis. However, there may be other risk factors which have not been described yet. Recent studies show that renalase is associated with cardiovascular events. The aim of this study was to reveal the relation between renalase, LVH in patients under hemodialysis (HD) treatment.

METHODS

The study included 50 HD patients and 35 healthy controls. Serum renalase levels and left ventricle mass index (LVMI) were measured in all participants and the relation between these variables was examined.

FINDINGS

LVMI was positively correlated with dialysis vintage and C-reactive protein (CRP) (r = 0.387, p = 0.005 and r = 0.597, p < 0.001, respectively) and was negatively correlated with residual diuresis and hemoglobin levels (r = -0.324, p = 0.022 and r = -0.499, p < 0.001, respectively). There was no significant association of renalase with LVMI in the HD patients (r = 0.263, p = 0.065). Serum renalase levels were significantly higher in HD patients (212 ± 127 ng/mL) compared to controls (116 ± 67 ng/mL) (p < 0.001). Renalase was positively correlated with serum creatinine and dialysis vintage (r = 0.677, p < 0.001 and r = 0.625, p < 0.001, respectively).

DISCUSSION

In our study, LVMI was correlated with dialysis vintage, residual diuresis, CRP, and hemoglobin. LVMI tends to correlate with renalase and this correlation may be significant in studies with more patient numbers. The main parameters affecting renalase levels are dialysis vintage and serum creatinine.

Early outgrowth pro-angiogenic cell number and function do not correlate with left ventricular structure and function in conventional hemodialysis patients: a cross-sectional study

Background

Left ventricular hypertrophy (LVH) is commonly found in chronic dialysis (CD) recipients, and is associated with impaired microvascular cardiac perfusion and heart failure. In response to LVH and cardiac ischemia, early outgrowth pro-angiogenic cellS(EPCs) mobilize from the bone marrow to facilitate angiogenesis and endothelial repair. In the general population, EPC number and function correlate inversely with cardiovascular risk. In end-stage renal disease (ESRD), EPC number and function are generally reduced.

Objectives

To test whether left ventricular abnormalities retain their potent ability to promote EPC reparative responses in the setting of ESRD.

Design

Cross-sectional study.

Setting

St. Michael’s Hospital, Toronto, Ontario, Canada.

Patients

47 prevalent chronic dialysis recipients.

Measurements

(1) circulating CD34⁺ and CD133⁺ EPC number, (2) cultured EPC migratory ability, in vitro differentiation potential, and apoptosis rate, and (3) cardiac magnetic resonance-measured LV mass, volume and ejection fraction.

Methods

Bivariate correlation analysis was performed with Spearman's rho test.

Results

Of the 47 patients (mean age: 54 ± 13 years), the mean delivered urea reduction was 74 ± 10 %. Mean LV mass was 123 ± 38 g. Circulating CD34⁺ and CD133⁺ EPCs represented 0.14 % (IQR: 0.05 – 0.29 %) and 0.05 % (IQR: 0.01 – 0.10 %) of peripheral blood mononuclear cells. There were no significant correlations between any EPC parameter and measures of LV mass or ejection fraction.

Limitations

Lack of a non-ESRD control population, and the inability to measure all parameters of EPC function due to limitations in blood sampling. Our inability to measure cardiac VEGF expression prevented an assessment of changes in cardiac EPC mobilization signals.

Conclusions

These data suggest that in ESRD, the reparative EPC response to cardiac hypertrophy may be blunted. Further investigation of the effects of uremia on EPC physiology and its relationship to cardiac injury are required.

Effect of advanced chronic kidney disease in clinical and echocardiographic outcomes of patients treated with MitraClip system

BACKGROUND

Data regarding the influence of different levels of renal dysfunction on clinical and echocardiographic results of MitraClip therapy are scarce. We aimed to evaluate the impact of baseline advance renal failure in the outcomes of a cohort of patients treated with MitraClip.

METHODS AND RESULTS

We analyzed data from a multicenter registry of 173 patients treated with MitraClip between 2009 and 2012. Patients were classified as advanced chronic kidney disease (CKD, creatinine clearance [CrCl] <30 ml/min, group 1, n=20), moderate CKD (CrCl 30-60 ml/min, group 2, n=78) and normal renal function (CrCl >60 ml/min, group 3, n=75). Twenty patients (11.5%) presented advanced CKD. Procedural success was equal in the 3 groups (95.0% group 1, 100% in group 2 and 96.0% in group 3, p=0.180). Post-procedural MR and NYHA class at 1 month (MR ≥ 3+5.0% vs. 0% vs. 4.0% p=0.190 and NYHA>II 40.0% vs. 21.0% vs. 18.3%, p=0.101) and 6 months (MR ≥ 3+0% vs. 13.0% vs. 2.7%, p=0.330; and NYHA class>II 54.5% vs. 26.9% vs. 25.6%, p=0.298) did not differ between groups. However, patients in group 1 experienced higher frequency of the composite end-point of mortality or readmission at 16.2 ± 11.1 months of follow-up (HR 4.8, CI 95% 1.1-21.3).

CONCLUSION

Advanced CKD is linked to an excess of cardiac adverse events. This should be judiciously taken into account when selecting patients for MitraClip.

Cardiac complications of arteriovenous fistulas in patients with end-stage renal disease

Cardiovascular disease is the leading cause of the death in dialysis patients. Arteriovenous fistulas (AVFs) are associated with lower mortality and are viewed as the desired access option in most patients with advanced kidney disease needing dialysis. However, AVFs have significant and potentially deleterious effects on cardiac functions particularly in the setting of preexisting heart disease. This article provides a comprehensive and contemporary review to what is known about the impact of AVFs on: congestive heart failure, left ventricular hypertrophy, pulmonary hypertension, right ventricular dysfunction, coronary artery disease and valvular heart disease.

Cardiovascular co-morbidity in chronic kidney disease: Current knowledge and future research needs

Chronic kidney disease (CKD) is recognised as a health concern globally and leads to high rates of morbidity, mortality and healthcare expenditure. CKD is itself an independent risk factor for unfavorable health outcomes that include cardiovascular disease (CVD). Coronary artery disease is the primary type of CVD in CKD patients and a significant cause of death among renal transplant patients. Traditional and non-traditional risk factors for CVD exist in patients with CKD. Traditional factors include smoking, hypertension, dyslipidemia and diabetes which are highly prevalent in CKD patients. Non-traditional risk factors of CKD are mainly uraemia-specific and increase in prevalence as kidney function declines. Some examples of uraemia-specific risk factors that have been well documented include low levels of haemoglobin, albuminuria, and abnormal bone and mineral metabolism. Therapeutic interventions targeted at more traditional risk factors which contribute to CVD, have not had the desired effect on lowering CVD events and mortality in those suffering with CKD. Future research is warranted to delineate clear evidence to the benefit of modifying non-traditional risk factors.

Differential value of left ventricular mass index and wall thickness in predicting cardiovascular prognosis: data from the PAMELA population

BACKGROUND

Data on the prognostic value of echocardiographic left ventricular (LV) hypertrophy (LVH) as defined by LV wall thickness rather than LV mass estimate are scarce and not univocal. Thus, we investigated the value of LV mass index, wall thickness, and relative wall thickness (RWT) in predicting cardiovascular events in the PAMELA population.

METHODS

At entry 1,716 subjects underwent diagnostic tests, including laboratory investigations, 24-hour ambulatory blood pressure (BP) monitoring, and echocardiography. For the purpose of this analysis, all subjects were divided into quintiles of LV mass, LV mass/ body surface area (BSA), LV mass/height(2.7), interventricular septum (IVS), posterior wall (PW) thickness, IVS+PW thickness, and RWT.

RESULTS

Over a follow-up of 148 months, 139 nonfatal or fatal cardiovascular events were documented. After adjustment for age, sex, BP, fasting blood glucose, total cholesterol, and use of antihypertensive drugs, only the subjects stratified in the highest quintiles of LV mass indexed to body surface area (BSA) or height(2.7) exhibited a greater likelihood of incident cardiovascular disease (relative risk (RR) = 2.72, 95% confidence interval (CI) = 1.05-7.00, P = 0.03; RR = 4.83, 95% CI = 1.45-16.13, P = 0.01, respectively) as compared with the first quintile (reference group). The same was not true for the highest quintiles of IVS, PW thickness, IVS+PW thickness, and RWT. Similar findings were found when echocardiographic parameters were expressed as continuous variables.

CONCLUSIONS

This study indicates that LV wall thickness, different from LV mass index, does not provide a reliable estimate of cardiovascular risk associated with LVH in a general population. From these data it is recommended that echocardiographic laboratories should provide a systematic estimate of LV mass index, which is a strong, independent predictor of incident cardiovascular disease.

Reduction of Na/K-ATPase affects cardiac remodeling and increases c-kit cell abundance in partial nephrectomized mice

The current study examined the role of Na/K-ATPase α1-subunit in animals subjected to 5/6th partial nephrectomy (PNx) using Na/K-ATPase α1-heterozygous (α1(+/-)) mice and their wild-type (WT) littermates. After PNx, both WT and α1(+/-) animals displayed diastolic dimension increases, increased blood pressure, and increased cardiac hypertrophy. However, in the α1(+/-) animals we detected significant increases in cardiac cell death in PNx animals. Given that reduction of α1 elicited increased cardiac cell death with PNx, while at the same time these animals developed cardiac hypertrophy, an examination of cardiac cell number, and proliferative capabilities of those cells was carried out. Cardiac tissues were probed for the progenitor cell marker c-kit and the proliferation marker ki-67. The results revealed that α1(+/-) mice had significantly higher numbers of c-kit-positive and ki-67-positive cells, especially in the PNx group. We also found that α1(+/-) mice express higher levels of stem cell factor, a c-kit ligand, in their heart tissue and had higher circulating levels of stem cell factor than WT animals. In addition, PNx induced significant enlargement of cardiac myocytes in WT mice but has much less effect in α1(+/-) mice. However, the total cell number determined by nuclear counting is higher in α1(+/-) mice with PNx compared with WT mice. We conclude that PNx induces hypertrophic growth and high blood pressure regardless of Na/K-ATPase content change. However, total cardiac cell number as well as c-kit-positive cell number is increased in α1(+/-) mice with PNx.

Effects of residual renal function on left ventricle and analysis of related factors in patients with hemodialysis

BACKGROUND

Left ventricular hypertrophy (LVH) and systolic dysfunction would predict the mortality of patients undergoing maintenance hemodialysis. The cause of LVH is usually related to the increase of total peripheral vascular resistance and overloading volume. The presence of residual diuresis enables greater control of the volume. This study evaluated the effects of residual renal function (RRF) on the left ventricle and analyzed the related factors involved in hemodialysis patients.

METHODS

A total of 59 hemodialysis patients were classified into two groups. The patients in the RRF (RRF+) group had a urine volume greater than 200 mL/24 h, and the patients in the non-RRF (RRF-) group had a urine volume less than 200 mL/24 h. B-type natriuretic peptide (BNP), blood total homocysteine (tHcy), and blood biochemical indexes were determined for the patients in both groups. Echocardiography and Doppler tests were performed to determine the cardiac indexes.

RESULTS

LVH and systolic dysfunction in the RRF+ group were less severe than those in the RRF- group. The concentration of tHcy and BNP in patients with RRF was decreased in comparison with those without RRF. The concentration of tHcy and BNP was positively correlated with the residual diuresis.

CONCLUSIONS

There were distinct ventricular geometric patterns and different functional performances between RRF+ and RRF- groups. The presence of residual diuresis had a beneficial effect on the left ventricular function in hemodialysis patients.

Association of left ventricular mass with all-cause mortality, myocardial infarction and stroke

BACKGROUND

Our aim was to assess the association of left ventricular mass with mortality and nonfatal cardiovascular events.

METHODOLOGY/PRINCIPAL FINDINGS

Left ventricular mass was measured by echocardiography in 40138 adult patients (mean age 61.1 ± 16.4 years, 52.5% male). The primary endpoint was all-cause mortality. Secondary endpoints included nonfatal myocardial infarction and nonfatal stroke. During a mean follow-up period of 5.6 ± 3.9 years, 9181 patients died, 901 patients had a nonfatal myocardial infarction, and 2139 patients had a nonfatal stroke. Cumulative 10-year mortality was 26.8%, 31.9%, 37.4% and 46.4% in patients with normal, mildly, moderately and severely increased left ventricular mass, respectively (p<0.001). Ten-year rates of nonfatal myocardial infarction and stroke ranged from 3.2% and 6.7% in patients with normal left ventricular mass to 5.3% and 12.7% in those with severe increase in left ventricular mass, respectively. After multivariate adjustment, left ventricular mass remained an independent predictor of all-cause mortality (hazard ratio [HR] per 100 g increase 1.21, 95% confidence interval [CI] 1.14-1-27, p<0.001 in women, and HR 1.09, 95% CI 1.04-1-13, p<0.001 in men), myocardial infarction (HR 1.60, 95% CI 1.31-1.94, p<0.001 in women and HR 1.15, 95% CI 1.02-1.29, p=0.019 in men) and stroke (HR 1.26, 95% CI 1.13-1.40, p<0.001 in women and HR 1.19, 95% CI 1.09-1.30, p<0.001 in men).

CONCLUSIONS/SIGNIFICANCE

Left ventricular mass has a graded and independent association with all-cause mortality, myocardial infarction and stroke.

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.

Prognostic value of 48-hour ambulatory blood pressure measurement and cardiovascular mortality in hemodialysis patients

BACKGROUND

Hypertension is common and contributes to high cardiovascular morbidity and mortality in hemodialysis (HD) patients. It is unknown which blood pressure (BP) better defines the influence on cardiovascular mortality. The purpose of our study was to analyze the relationship between various BP measurements, traditional risk factors, markers of asymptomatic atherosclerosis [left ventricular mass (LVM), carotid intima media thickness (IMT)], and cardiovascular mortality in HD patients.

METHODS

Seventy-three patients (44 males and 29 females; mean age: 54.2 years) were included. BP was measured before and after HD and 48-hour ambulatory blood pressure monitoring (ABPM) was performed. Using sonography, the LVM index and carotid IMT were measured.

RESULTS

During a follow-up period up to 3,664 days, 28 patients died - 16 of them from cardiovascular causes. In a Cox regression model, which included age, gender, smoking, diabetes, sensitive C-reactive protein, albumin, hemoglobin, troponin T, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, calcium, phosphorus, carotid IMT, and LVM index, only 48-hour systolic ABPM (p = 0.037) and 48-hour diastolic ABPM (p = 0.006) turned out to be independent predictors of cardiovascular death.

CONCLUSION

Only 48-hour ABPM and not single BP measurements before or after HD were associated with cardiovascular mortality in HD patients.

Association of left atrial volume with mortality among ESRD patients with left ventricular hypertrophy referred for kidney transplantation

BACKGROUND

Left ventricular hypertrophy (LVH) is common in patients with end-stage renal disease (ESRD) and an independent risk factor for premature cardiovascular death. Left atrial volume (LAV), measured using echocardiography, predicts death in patients with ESRD. Cardiovascular magnetic resonance (CMR) imaging is a volume-independent method of accurately assessing cardiac structure and function in patients with ESRD.

STUDY DESIGN

Single-center prospective observational study to assess the determinants of all-cause mortality, particularly LAV, in a cohort of ESRD patients with LVH, defined using CMR imaging.

SETTING & PARTICIPANTS

201 consecutive ESRD patients with LVH (72.1% men; mean age, 51.6 +/- 11.7 years) who had undergone pretransplant cardiovascular assessment were identified using CMR imaging between 2002-2008. LVH was defined as left ventricular mass index >84.1 g/m(2) (men) or >74.6 g/m(2) (women) based on published normal left ventricle dimensions for CMR imaging. Maximal LAV was calculated using the biplane area-length method at the end of left ventricle systole and corrected for body surface area.

PREDICTORS

CMR abnormalities, including LAV.

OUTCOME

All-cause mortality.

RESULTS

54 patients died (11 after transplant) during a median follow-up of 3.62 years. Median LAV was 30.4 mL/m(2) (interquartile range, 26.2-58.1). Patients were grouped into high (median or higher) or low (less than median) LAV. There were no significant differences in heart rate and mitral valve Doppler early to late atrial peak velocity ratio. Increased LAV was associated with higher mortality. Kaplan-Meier survival analysis showed poorer survival in patients with higher LAV (log rank P = 0.01). High LAV and left ventricular systolic dysfunction conferred similar risk and were independent predictors of death using multivariate analysis.

LIMITATIONS

Only patients undergoing pretransplant cardiac assessment are included. Limited assessment of left ventricular diastolic function.

CONCLUSIONS

Higher LAV and left ventricular systolic dysfunction are independent predictors of death in ESRD patients with LVH.

Effects of Altered Volume Loading on Left Ventricular Hemodynamics and Diastolic Filling During Hemodialysis

BACKGROUND

Changes in the circulating volume associated with hemodialysis (HD) resulted in alternations of left ventricular (LV) filling. However, previous studies offered conflicting findings. This study thus evaluated the impact of HD on LV diastolic filling indices and hemodynamics.

MATERIALS AND METHODS

Forty patients with end-stage renal disease were studied by Doppler echocardiography immediately before and after HD. The cardiac size, volume and mass were determined by M-mode and two-dimensional echocardiography. LV diastolic filling parameters and hemodynamics were assessed from mitral inflow using Doppler echocardiography.

RESULTS

Left atrial and LV dimension, LV volume, and LV mass decreased significantly after HD (p<0.001). Cardiac output declined from 5.74+/-1.37 to 4.98+/-1.27 L/min (p<0.001), whereas, the ejection fraction remained unchanged. HD elicited marked changes in the early diastolic E (95.1+/-20.5 to 70.3+/-18.2 cm/s, p<0.001) and late atrial filling A velocities (104.3+/-20.9 to 88.9+/-16.9 cm/s, p<0.001). In addition, correction of the deceleration time of E and isovolumic relaxation time prolonged significantly (p=0.011 and p<0.001, respectively).

CONCLUSIONS

Findings in this study indicate that HD altering the loading condition significantly influenced the LV diastolic function and hemodynamics. Moreover, Doppler echocardiography provides an effective means of assessing the effects on LV diastolic filling and hemodynamics during HD.

Anaemia in diabetic renal failure: is there a role for early erythropoietin treatment in preventing cardiovascular mortality?

The mortality rate in diabetics with chronic kidney disease (CKD) is seven times higher than end-stage renal disease mainly because of cardiac causes. Anaemia may have a relevant role in the pathogenesis of cardiovascular (CV) disease in CKD. Anaemia occurs at an earlier stage of CKD in diabetic individuals than in those with other causes of CKD. Observational findings support the unfavourable influence of anaemia on mortality in CKD patients, and the combination of anaemia and CKD in diabetics identifies a group with a particularly high mortality risk. While the effect of erythropoietin on these patients' quality of life is known, its impact on mortality and CV risk is uncertain. The recent Anaemia Correction in Diabetes (ACORD) trial in diabetic CKD patients, which targeted haemoglobin levels of 13-15 mg/dl, disclosed no statistically significant favourable or adverse effects on mortality or morbidity over the 2-year follow-up, while other studies endeavouring to nearly normalize haemoglobin have reportedly proved risky. Even if anaemia is causally involved, the pathogenesis of CV disease in diabetics with CKD is so complex that addressing just one factor (anaemia) may not suffice to prevent CV risk, and normalizing haemoglobin levels may even be harmful.

Anemia, renal transplantation, and the anemia paradox

Anemia is prevalent in renal transplant recipients (RTRs), as it is in all chronic kidney disease (CKD) populations. Mild anemia occurs in up to 40% of RTRs, and more severe anemia (110 g/L) occurs in about 9% to 22% of patients. As in CKD, impaired graft (renal) function is a major predictor of anemia identified in nearly all studies, suggesting a major role for erythropoietin deficiency. Chronic inflammation, malnutrition, iron deficiency, and medications (angiotensin converting enzyme inhibitors, angiotensin receptor blockers, mycophenolate, azathioprine, and sirolimus) are contributory factors seen in some, but not all, studies. Although pathophysiologic and observational data strongly support a causal association between low hemoglobin levels and cardiovascular outcomes in RTRs, no randomized controlled trial to date has been able to show a clear benefit of anemia treatment on cardiovascular outcomes or mortality in either RTR or other CKD populations. This important paradox has led some investigators to question the causal nature of the association between anemia and heart disease. Resolution of this paradox, at least for patients with stage 2/3 CKD, will depend on the outcome of randomized controlled trials currently in progress. Similar trials sorely are needed in renal transplant populations. In the interim, current opinion favors treating persistent anemia in RTRs to achieve targets similar to those recommended for dialysis and CKD patients.

Current understanding of optimal blood pressure goals in dialysis patients

The hemodialysis population is associated with a very low survival rate, with myocardial infarctions and strokes accounting for most of the increased mortality. Recent observational studies demonstrate a paradoxical relationship between increasing blood pressure and increasing mortality. Hypertension treated with antihypertensive medications unequivocally reduces cerebrovascular risk, but demonstration of a survival benefit for cardiovascular mortality has proven more difficult to demonstrate. Increased pulse pressure is caused by inadequate dialysis treatment that increases arterial wall stiffness and afterload, and decreases coronary perfusion. The disproportionate representation of diastolic dysfunction and coronary artery atherosclerosis may explain why increased pulse pressure is associated with higher cardiovascular risk for the dialysis population. Optimum blood pressure control has not been established, due to a lack of prospective studies targeting blood pressure reduction. Opinion-based recommendations are offered, but goals should be individualized based on a complete assessment of prevailing comorbidities and should target normalization of the pulse pressure.

Canadian Randomized Trial of Hemoglobin Maintenance to Prevent or Delay Left Ventricular Mass Growth in Patients With CKD

BACKGROUND

This randomized clinical trial is designed to assess whether the prevention and/or correction of anemia, by immediate versus delayed treatment with erythropoietin alfa in patients with chronic kidney disease, would delay left ventricular (LV) growth. Study design and sample size calculations were based on previously published Canadian data.

METHODS

One hundred seventy-two patients were randomly assigned. The treatment group received therapy with erythropoietin alfa subcutaneously to maintain or achieve hemoglobin (Hgb) level targets of 12.0 to 14.0 g/dL (120 to 140 g/L). The control/delayed treatment group had Hgb levels of 9.0 +/- 0.5 g/dL (90 +/- 5 g/L) before therapy was started: target level was 9.0 to 10.5 g/dL (90 to 105 g/L). Optimal blood pressure and parathyroid hormone, calcium, and phosphate level targets were prescribed; all patients were iron replete. The primary end point is LV growth at 24 months.

RESULTS

One hundred fifty-two patients were eligible for the intention-to-treat analysis: mean age was 57 years, 30% were women, 38% had diabetes, and median glomerular filtration rate was 29 mL/min (0.48 mL/s; range, 12 to 55 mL/min [0.20 to 0.92 mL/s]). Blood pressure and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use were similar in the control/delayed treatment and treatment groups at baseline. Erythropoietin therapy was administered to 77 of 78 patients in the treatment group, with a median final dose of 2,000 IU/wk. Sixteen patients in the control/delayed treatment group were administered erythropoietin at a median final dose of 3,000 IU/wk. There was no statistically significant difference between groups for the primary outcome of mean change in LV mass index (LVMI) from baseline to 24 months, which was 5.21 +/- 30.3 g/m2 in the control/delayed treatment group versus 0.37 +/- 25.0 g/m2 in the treatment group. Absolute mean difference between groups was 4.85 g/m2 (95% confidence interval, -4.0 to 13.7; P = 0.28). Mean Hgb level was greater in the treatment group throughout the study and at study end was 12.75 g/dL (127.5 g/L in treatment group versus 11.46 g/dL [114.6 g/L] in control/delayed treatment group; P = 0.0001). LV growth occurred in 20.1% in the treatment group versus 31% in the control/delayed treatment group (P = 0.136). In patients with a stable Hgb level, mean LVMI did not change (-0.25 +/- 26.7 g/m2), but it increased in those with decreasing Hgb levels (19.3 +/- 28.2 g/m2; P = 0.002).

CONCLUSION

This trial describes disparity between observational and randomized controlled trial data: observed and randomly assigned Hgb level and LVMI are not linked; thus, there is strong evidence that the association between Hgb level and LVMI likely is not causal. Large randomized controlled trials with unselected patients, using morbidity and mortality as outcomes, are needed.