Myocardial fibrosis and diastolic dysfunction in patients on chronic haemodialysis

Diastolic function in chronic kidney disease

Chronic kidney disease (CKD) is characterized by clustered age-independent concentric left ventricular (LV) geometry, geometry-independent systolic dysfunction and age and heart rate-independent diastolic dysfunction. Concentric LV geometry is always associated with echocardiographic markers of abnormal LV relaxation and increased myocardial stiffness, two hallmarks of diastolic dysfunction. Non-haemodynamic mechanisms such as metabolic and electrolyte abnormalities, activation of biological pathways and chronic exposure to cytokine cascade and the myocardial macrophage system also impact myocardial structure and impair the architecture of the myocardial scaffold, producing and increasing reactive fibrosis and altering myocardial distensibility. This review addresses the pathophysiology of diastole in CKD and its relations with cardiac mechanics, haemodynamic loading, structural conditions, non-haemodynamic factors and metabolic characteristics. The three mechanisms of diastole will be examined: elastic recoil, active relaxation and passive distensibility and filling. Based on current evidence, we briefly provide methods for quantification of diastolic function and discuss whether diastolic dysfunction represents a distinct characteristic in CKD or a proxy of the severity of the cardiovascular condition, with the potential to be predicted by the general cardiovascular phenotype. Finally, the review discusses assessment of diastolic function in the context of CKD, with special emphasis on end-stage kidney disease, to indicate whether and when in-depth measurements might be helpful for clinical decision making in this context.

Comparison of left atrial deformation parameters between renal transplant and hemodialysis patients

Background

Renal transplantation (RT) has been demonstrated to improve left ventricular systolic function. However, only few studies have attempted to reveal the effects of transplantation on left atrial (LA) function. In our study, we aimed to compare LA function between RT and hemodialysis patients.

Methods

This cross-sectional study included 75 consecutive patients with RT, and 75 age- and gender-matched patients on maintenance hemodialysis. LA strain and strain rate (SR) analyzed by two-dimensional (2D) speckle tracking echocardiography (STE) were compared between the groups in addition to standard echocardiographic parameters.

Results

LA strain during reservoir phase (29.88 ± 5.76% vs 26.11 ± 5.74%, P < .001), LA strain during conduit phase (− 15.28 ± 5.00% vs − 12.92 ± 4.38%, P = .003), and LA strain during contraction phase (− 14.60 ± 3.32% vs − 13.19 ± 3.95%, P = .020) were higher in the transplantation group. Similarly, LA peak SR during reservoir phase (1.54 ± 0.33 s^− 1 vs 1.32 ± 0.33 s^− 1, P < .001), LA peak SR during conduit phase (− 1.47 ± 0.49 s^− 1 vs − 1.12 ± 0.42 s^− 1, P < .001), and LA peak SR during contraction phase (− 2.13 ± 0.46 s^− 1 vs − 1.83 ± 0.58 s^− 1, P = .001) were higher in the transplantation group as well.

Conclusions

LA function assessed by 2D STE was better in RT patients than hemodialysis patients. This may suggest favorable effects of RT on LA function.

Diastolic and systolic left ventricular dysfunction and mortality in chronic kidney disease patients on haemodialysis

AIMS

Left ventricular diastolic dysfunction (LVDD) and LV systolic dysfunction (LVSD) are prevalent in CKD, but their prognostic relevance is debatable. We intent to verify whether LVDD and LVSD are independently predictive of all-cause mortality and if they have comparable or different effects on outcomes.

METHODS

A retrospective analysis was conducted of the echocardiographic data of 1285 haemodialysis patients followed up until death or transplantation. LVDD was classified into 4 grades of severity. Endpoint was all-cause mortality.

RESULTS

During a follow-up of 30 months, 419/1285 (33%) patients died, 224 (53%) due to CV events. LVDD occurred in 75% of patients, grade 1 DD was the prevalent diastolic abnormality, and pseudonormal pattern was the predominant form of moderate-severe DD. Moderate-severe LVDD (HR 1.379, CI% 1.074-1.770) and LVSD (HR 1.814, CI% 1.265-2.576) independently predicted death; a graded, progressive association was found between LVDD categories and the risk of death; and the impact of isolated severe-moderate LVDD on the risk of death was comparable to that exercised by isolated compromised LV systolic function.

CONCLUSION

Moderate-severe LVDD and LVSD were independently associated with a higher probability of death and had a similar impact on survival. A progressive association was observed between LVDD grades and mortality.

Fish oil replacement prevents, while docosahexaenoic acid-derived protectin DX mitigates end-stage-renal-disease in atherosclerotic diabetic mice

Diabetic nephropathy (DN) remains the major cause of end-stage renal disease (ESRD). We used high-fat/high-sucrose (HFHS)-fed LDLr^-/- /ApoB^100/100 mice with transgenic overexpression of IGFII in pancreatic β-cells (LRKOB100/IGFII) as a model of ESRD to test whether dietary long chain omega-3 polyunsaturated fatty acids LCω3FA-rich fish oil (FO) could prevent ESRD development. We further evaluated the potential of docosahexaenoic acid (DHA)-derived pro-resolving lipid mediators, 17-hydroxy-DHA (17-HDHA) and Protectin DX (PDX), to reverse established ESRD damage. HFHS-fed vehicle-treated LRKOB100/IGFII mice developed severe kidney dysfunction leading to ESRD, as revealed by advanced glomerular fibrosis and mesangial expansion along with reduced percent survival. The kidney failure outcome was associated with cardiac dysfunction, revealed by reduced heart rate and prolonged diastolic and systolic time. Dietary FO prevented kidney damage, lean mass loss, cardiac dysfunction, and death. 17-HDHA reduced podocyte foot process effacement while PDX treatment alleviated kidney fibrosis and mesangial expansion as compared to vehicle treatment. Only PDX therapy was effective at preserving the heart function and survival rate. These results show that dietary LCω3FA intake can prevent ESRD and cardiac dysfunction in LRKOB100/IGFII diabetic mice. Our data further reveals that PDX can protect against renal failure and cardiac dysfunction, offering a potential new therapeutic strategy against ESRD.

Association of Post Transplantation Anaemia and Persistent Secondary Hyperparathyroidism with Diastolic Function in Stable Kidney Transplant Recipients

Introduction

We hypothesized that post transplantation anaemia and persistent secondary hyperparathyroidism are potential determinants of diastolic function in stable kidney transplant recipients.

Methods

We assessed traditional and non-traditional cardiovascular risk factors and determined carotid artery intima-media thickness and plaque by ultrasound, arterial function by applanation tonometry using SphygmoCor software and diastolic function by echocardiography in 43 kidney transplant recipients with a transplant duration of ≥6 months, no acute rejection and a glomerular filtration rate of ≥15 mL/min/1.73m².

Results

Mean (SD; range) transplant duration was 12.3 (8.0; 0.5–33.8) years. Post transplantation anaemia and persistent secondary hyperparathyroidism were identified in 27.9% and 30.8% of the patients, respectively; 67.5% of the participants were overweight or obese. In established confounder adjusted analysis, haemoglobin (partial R=−0.394, p=0.01) and parathyroid hormone concentrations (partial R=0.382, p=0.02) were associated with E/e’. In multivariable analysis, haemoglobin (partial R=−0.278, p=0.01) and parathyroid levels (partial R=0.324, p=0.04) were independently associated with E/e’. Waist–height ratio (partial R=−0.526, p=0.001 and partial R=−0.355, p=0.03), waist circumference (partial R=−0.433, p=0.008 and partial R=−0.393, p=0.02) and body mass index (partial R=−0.332, p=0.04 and partial R=−0.489, p=0.002) were associated with both e’ and E/A, respectively, in established confounder adjusted analysis. The haemoglobin-E/e’ (partial R=−0.422, p=0.02), parathyroid hormone-E/e’ (partial R=0.434, p=0.03), waist–height ratio-e’ (partial R=−0.497, p=0.007) and body mass index-E/A (partial R=−0.386, p=0.04) relationships remained consistent after additional adjustment for left ventricular mass index and cardiac preload and afterload measures.

Conclusion

Haemoglobin and parathyroid hormone concentrations as well as adiposity measures are independently associated with diastolic function in kidney transplant recipients. Whether adequate management of post transplantation anaemia, persistent secondary hyperparathyroidism and excess adiposity can prevent the development of heart failure with preserved ejection fraction in kidney transplant recipients merits further investigation.

Associations of B-type natriuretic peptide (BNP) and dialysis vintage with CMRI-derived cardiac indices in stable hemodialysis patients with a preserved left ventricular ejection fraction

To assess left ventricular myocardial native T1/T2 values and systolic strain and their associations with B-type natriuretic peptide (BNP) and dialysis vintage in hemodialysis (HD) patients with a preserved left ventricular ejection fraction (LVEF). Forty-three HD patients with end-stage renal disease (ESRD) but a preserved LVEF (≥ 50%) and 28 healthy volunteers were enrolled. BNP was measured at the time of cardiac magnetic resonance (CMR) measurements. Global native T1 and T2 values were significantly higher in the HD patients (native T1: 1056 ± 32 ms vs. 1006 ± 25 ms, p < 0.001; T2: 50 ± 3 ms vs. 46 ± 2 ms, p < 0.001) than in the controls. The mean peak global circumferential strain (GCS) and global longitudinal strain (GLS) were both significantly reduced in the HD patients compared with the controls (GCS: - 13 ± 3 vs. - 16 ± 3, p < 0.001; GLS: - 12 ± 4 vs. - 15 ± 3, p = 0.001). In the HD patients, the global native T1 value showed a positive correlation with the global T2 value (r = 0.311, p = 0.042) and significant correlations with GCS (r = 0.564, p < 0.001) and GLS (r = 0.359, p = 0.018). Significant positive correlations were found between lg BNP levels and T2 values (r = 0.569, p < 0.0001) and the left atrial volume index (LAVI) (r = 0.536, p = 0.012). GLS showed significant positive correlations with the LVMI (r = 0.354, p = 0.020) and dialysis vintage (p = 0.026; r = - 0.339) in the HD patients. HD patients with a preserved LVEF have increased native T1/T2 values and decreased strain compared to controls. T2 values and the LVAI were positively associated with BNP in HD patients.

The Impact of Perioperative Factors on Changes in Diastolic Function after Kidney Transplantation: A Retrospective Analysis

PURPOSE

Cardiac changes in end-stage renal disease are the most common causes of death after kidney transplantation (KT). Chronic kidney disease presents a major risk factor for the development and progression of diastolic dysfunction. The purpose of this study was to identify the association between changes in left ventricular (LV) diastolic function and perioperative clinical factors in patients with preserved ejection fraction following KT.

MATERIALS AND METHODS

We reviewed 115 patients who underwent KT between January 2011 and December 2015 with both preand post-transplant echocardiograms; patients with LV systolic dysfunction were excluded. LV diastolic function was measured using the ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/e').

RESULTS

Patients with normal pre-operative LV systolic function (n=97) showed improvement in E/e' after KT (11.9±4.4 to 10.5±3.8, p=0.023). Additionally, post-KT estimated glomerular filtration ratio was associated with changes in E/e' (odds ratio, -0.056; 95% confidence interval, -0.014 to -0.007; p=0.026). Among patients with preexisting diastolic dysfunction (20/97 patients), the amount of intraoperative fluid administration was related to E/e' changes (odds ratio, 0.003; 95% confidence interval, 0.000 to 0.005; p=0.029).

CONCLUSION

KT is associated with improved diastolic function. Post-KT renal function was significantly related to changes in LV diastolic function. The amount of intraoperative fluid was a risk factor for worsening diastolic function after KT in patients with preexisting diastolic dysfunction.

The prognostic significance of preoperative left ventricular diastolic dysfunction and left atrial enlargement on acute coronary syndrome in kidney transplantation

Echocardiography is commonly performed as a screening test to evaluate perioperative risks before kidney transplantation. However, only limited data are available on echocardiographic parameters of left ventricular diastolic dysfunction (LVDD) and left atrial enlargement (LAE) on acute coronary syndrome and mortality in kidney transplant recipients. We reviewed 2779 adult recipients who underwent pretransplant echocardiography from 1997 to 2012. We divided the patients into two and four groups by two categories: LVDD grades 0-1 vs. 2-3, and left atrial size quartile groups. During a mean follow-up of 4.5 years, acute coronary syndrome occurred in 89 (3.2%) patients. The recipients with LVDD grades 2-3 (P = 0.005 for non-fatal, P = 0.02 for fatal/non-fatal) and LAE (P = 0.001 for non-fatal, P = 0.03 for fatal/non-fatal) had a higher incidence of acute coronary syndrome after kidney transplantation. All-cause mortality did not differ significantly between the groups. In a multivariate analysis, LVDD of grades 2-3 (hazard ratio 2.98, 95% confidence interval 1.535-5.787; P = 0.001), and LAE (hazard ratio 1.052, 95% confidence interval 1.006-1.101; P = 0.03) were independently associated with non-fatal acute coronary syndrome. In patients who are kidney transplant candidates, pretransplant LVDD and LAE were independently associated with a higher incidence of acute coronary syndrome after kidney transplantation.

Calcium as a cardiovascular toxin in CKD-MBD

Disordered calcium balance and homeostasis are common in patients with chronic kidney disease. Such alterations are commonly associated with abnormal bone remodeling, directly and indirectly. Similarly, positive calcium balance may also be a factor in the pathogenesis of extra skeletal soft tissue and arterial calcification. Calcium may directly affect cardiac structure and function through direct effects to alter cell signaling due to abnormal intracellular calcium homeostasis 2) extra-skeletal deposition of calcium and phosphate in the myocardium and small cardiac arterioles, 3) inducing cardiomyocyte hypertrophy through calcium and hormone activation of NFAT signaling mechanisms, and 4) increased aorta calcification resulting in chronic increased afterload leading to hypertrophy. Similarly, calcium may alter vascular smooth muscle cell function and affect cell signaling which may predispose to a proliferative phenotype important in arteriosclerosis and arterial calcification. Thus, disorders of calcium balance and homeostasis due to CKD-MBD may play a role in the high cardiovascular burden observed in patients with CKD.

Imaging of Myocardial Fibrosis in Patients with End-Stage Renal Disease: Current Limitations and Future Possibilities

Cardiovascular disease in patients with end-stage renal disease (ESRD) is driven by a different set of processes than in the general population. These processes lead to pathological changes in cardiac structure and function that include the development of left ventricular hypertrophy and left ventricular dilatation and the development of myocardial fibrosis. Reduction in left ventricular hypertrophy has been the established goal of many interventional trials in patients with chronic kidney disease, but a recent systematic review has questioned whether reduction of left ventricular hypertrophy improves cardiovascular mortality as previously thought. The development of novel imaging biomarkers that link to cardiovascular outcomes and that are specific to the disease processes in ESRD is therefore required. Postmortem studies of patients with ESRD on hemodialysis have shown that the extent of myocardial fibrosis is strongly linked to cardiovascular death and accurate imaging of myocardial fibrosis would be an attractive target as an imaging biomarker. In this article we will discuss the current imaging methods available to measure myocardial fibrosis in patients with ESRD, the reliability of the techniques, specific challenges and important limitations in patients with ESRD, and how to further develop the techniques we have so they are sufficiently robust for use in future clinical trials.

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.

Cardiorenal syndrome type 4: A study of cardiovascular diseases in chronic kidney disease

INTRODUCTION

The heart and the kidneys are tightly interlinked with each other. So, primary disorder of one of these organs often results in the secondary dysfunction of other. Such interactions play a vital role in the pathogenesis of a clinical entity called cardio-renal syndrome (CRS). CRS type 4 refers to the development of cardiac failure in the patients with CKD.

OBJECTIVES

To study the prevalence of various cardiac diseases in the patients with CKD and risk factors for it.

METHODS

Eighty patients with CKD who were being treated at KIMS, Hubli, from 1st January 2015 to 30th June 2015 were selected. Clinical evaluation and relevant investigations including echocardiography were done.

RESULTS

Mean age of study population was 43.50±14.53 years. Heart failure with reduced ejection fraction (HFrEF) and Heart Failure with preserved ejection fraction (HFpEF) were present in 21 (26.25%) and 59 (73.75%) respectively. Left ventricular (LV) hypertrophy was present in 55(68.75%). Thus, the prevalence of CRS type 4 was 61 (76.25%). Pericardial effusion was present in 12 (15%). Complete heart block was present in 2 (2.5%). Pulmonary hypertension (PH) was present in 35 (43.75%). Mean central venous pressure (CVP) and interdialysis fluid retention were significantly greater among those with LV failure, compared to those without LV failure (p=0.0002, p=0.025 respectively). Mean hemoglobin was significantly lower among patients with LV failure, compared to those without LV failure (p=0.032).

CONCLUSION

The prevalence of cardiorenal syndrome type 4 is substantially high in patients with CKD and carries adverse outcome in relation to patient management.

Design and methods of CYCLE-HD: improving cardiovascular health in patients with end stage renal disease using a structured programme of exercise: a randomised control trial

BACKGROUND

There is emerging evidence that exercise training could positively impact several of the cardiovascular risk factors associated with sudden cardiac death amongst patients on haemodialysis. The primary aim of this study is to evaluate the effect of an intradialytic exercise programme on left ventricular mass.

METHOD AND DESIGN

Prospective, randomised cluster open-label blinded endpoint clinical trial in 130 patients with end stage renal disease on haemodialysis. Patients will be randomised 1:1 to either 1) minimum of 30 min continuous cycling thrice weekly during dialysis or 2) standard care. The primary outcome is change in left ventricular mass at 6 months, assessed by cardiac MRI (CMR). In order to detect a difference in LV mass of 15 g between groups at 80 % power, a sample size of 65 patients per group is required. Secondary outcome measures include abnormalities of cardiac rhythm, left ventricular volumes and ejection fraction, physical function measures, anthropometric measures, quality of life and markers of inflammation, with interim assessment for some measures at 3 months.

DISCUSSION

This study will test the hypothesis that an intradialytic programme of exercise leads to a regression in left ventricular mass, an important non-traditional cardiovascular risk factor in end stage renal disease. For the first time this will be assessed using CMR. We will also evaluate the efficacy, feasibility and safety of an intradialytic exercise programme using a number of secondary end-points. We anticipate that a positive outcome will lead to both an increased patient uptake into established intradialytic programmes and the development of new programmes nationally and internationally.

TRIAL REGISTRATION NUMBER

ISRCTN11299707 (registration date 5(th) March 2015).

Characterisation of cardiomyopathy by cardiac and aortic magnetic resonance in patients new to hemodialysis

Objectives

Cardiomyopathy is a key factor in accelerated cardiovascular mortality in haemodialysis (HD) patients. We aimed to phenotype cardiac and vascular dysfunction by tagged cardiovascular magnetic resonance (CMR) imaging in patients recently commencing HD.

Methods

Fifty-four HD patients and 29 age and sex-matched controls without kidney disease were studied. Left ventricular (LV) mass, volumes, ejection fraction (EF), concentric remodelling, peak-systolic circumferential strain (PSS), peak diastolic strain rate (PDSR), LV dyssynchrony, aortic distensibility and aortic pulse wave velocity were determined.

Results

Global systolic function was reduced (EF 51 ± 10%, HD versus 59 ± 5%, controls, p < 0.001; PSS 15.9 ± 3.7% versus 19.5 ± 3.3%, p < 0.001). Diastolic function was decreased (PDSR 1.07 ± 0.33s^-1 versus 1.31 ± 0.38s^-1, p = 0.003). LV mass index was increased (63[54,79]g/m² versus 46[42,53]g/m², p < 0.001). Anteroseptal reductions in PSS were apparent. These abnormalities remained prevalent in the subset of HD patients with preserved EF >50% (n = 35) and the subset of HD patients without diabetes (n = 40). LV dyssynchrony was inversely correlated to diastolic function, EF and aortic distensibility. Diastolic function was inversely correlated to LV dyssynchrony, concentric remodelling, age and aortic pulse wave velocity.

Conclusion

Patients new to HD have multiple cardiac and aortic abnormalities as characterised by tagged CMR. Cardio-protective interventions are required from initiation of therapy.

Key Points

• First characterisation of cardiomyopathy by tagged CMR in haemodialysis patients.

• Diastolic function was correlated to LV dyssynchrony, concentric remodelling and aortic PWV.

• Reductions in strain localised to the septal and anterior wall.

• Bioimpedance measures were unrelated to LV strain, suggesting volume-independent pathogenetic mechanisms.

• Multiple abnormalities persisted in the HD patient subset with preserved EF or without diabetes.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-015-4096-2) contains supplementary material, which is available to authorized users.

Novel plasma and imaging biomarkers in heart failure with preserved ejection fraction

Existing diagnostic guidelines for heart failure with preserved ejection fraction (HFPEF) primarily comprise natriuretic peptides and echocardiographic assessment, highlighting the role of diastolic dysfunction. However, recent discoveries of novel plasma markers implicated in pathophysiology of heart failure and technological advances in imaging provide additional biomarkers which are potentially applicable to HFPEF. The evidence base for plasma extra-cellular matrix (ECM) peptides, galectin-3, ST2, GDF-15 and pentraxin-3 is reviewed. Furthermore, the capabilities of novel imaging techniques to assess existing parameters (e.g. left ventricular ejection fraction, systolic & diastolic function, chamber size) and additional derangements of the ECM, myocardial mechanics and ischaemia evaluation are addressed.

Relationship between different blood pressure measurements and left ventricular mass by cardiac magnetic resonance imaging in end-stage renal disease

Hypertension is prevalent in patients with end-stage renal disease and is strongly associated with left ventricular hypertrophy (LVH), an independent predictor of cardiovascular mortality. Blood pressure (BP) monitoring in hemodialysis patients may be unreliable because of its lability and variability. We compared different methods of BP measurement and their relationship with LVH on cardiac magnetic resonance imaging. Sixty patients undergoing chronic hemodialysis at a single dialysis center had BP recorded at each dialysis session over 12 weeks: pre-dialysis, initial dialysis, nadir during dialysis, and post-dialysis. Forty-five of these patients also underwent 44-hour inter-dialytic ambulatory BP monitoring. Left ventricular mass index (LVMI) was measured using cardiac magnetic resonance imaging and the presence of LVH was ascertained. Receiver operator characteristic curves were generated for each BP measurement for predicting LVH. The mean LVMI was 68 g/m(2) (SD = 15 g/m(2)); 13/60 patients (22%) had LVH. Mean arterial pressure measured shortly after initiation of dialysis session was most strongly correlated with LVMI (Pearson correlation coefficient r = 0.59, P < .0001). LVH was best predicted by post-dialysis systolic BP (area under the curve, 0.83; 95% confidence interval, 0.72-0.94) and initial dialysis systolic BP (area under the curve, 0.81; 95% confidence interval, 0.70-0.92). Forty-four-hour ambulatory BP and BP variability did not significantly predict LVH. Initial dialysis mean arterial pressure and systolic BP and post-dialysis systolic BP are the strongest predictors of LVH, and may represent the potentially best treatment targets in hemodialysis patients to prevent end-organ damage. Further studies are needed to confirm whether treatment targeting these BP measurements can optimize cardiovascular outcomes.

Myocardial T1 mapping: techniques and potential applications

Myocardial fibrosis is a common endpoint in a variety of cardiac diseases and a major independent predictor of adverse cardiac outcomes. Short of histopathologic analysis, which is limited by sampling bias, most diagnostic modalities are limited in their depiction of myocardial fibrosis. Cardiac magnetic resonance (MR) imaging has the advantage of providing detailed soft-tissue characterization, and a variety of novel quantification methods have further improved its usefulness. Contrast material-enhanced cardiac MR imaging depends on differences in signal intensity between regions of scarring and adjacent normal myocardium. Diffuse myocardial fibrosis lacks these differences in signal intensity. Measurement of myocardial T1 times (T1 mapping) with gadolinium-enhanced inversion recovery-prepared sequences may depict diffuse myocardial fibrosis and has good correlation with ex vivo fibrosis content. T1 mapping calculates myocardial T1 relaxation times with image-based signal intensities and may be performed with standard cardiac MR imagers and radiologic workstations. Myocardium with diffuse fibrosis has greater retention of contrast material, resulting in T1 times that are shorter than those in normal myocardium. Early studies have suggested that diffuse myocardial fibrosis may be distinguished from normal myocardium with T1 mapping. Large multicenter studies are needed to define the role of T1 mapping in developing prognoses and therapeutic assessments. However, given its strengths as a noninvasive method for direct quantification of myocardial fibrosis, T1 mapping may eventually play an important role in the management of cardiac disease.

Predictive value of echocardiographic parameters for clinical events in patients starting hemodialysis

Echocardiographic parameters can predict cardiovascular events in several clinical settings. However, which echocardiographic parameter is most predictive of each cardiovascular or non-cardiovascular event in patients starting hemodialysis remains unresolved. Echocardiography was used in 189 patients at the time of starting hemodialysis. We established primary outcomes as follows: cardiovascular events (ischemic heart disease, cerebrovascular disease, peripheral artery disease, and acute heart failure), fatal non-cardiovascular events, all-cause mortality, and all combined events. The most predictable echocardiographic parameter was determined in the Cox hazard ratio model with a backward selection after the adjustment of multiple covariates. Among several echocardiographic parameters, the E/e' ratio and the left ventricular end-diastolic volume (LVEDV) were the strongest predictors of cardiovascular and non-cardiovascular events, respectively. After the adjustment of clinical and biochemical covariates, the predictability of E/e' remained consistent, but LVEDV did not. When clinical events were further analyzed, the significant echocardiographic parameters were as follows: s' for ischemic heart disease and peripheral artery disease, LVEDV and E/e' for acute heart failure, and E/e' for all-cause mortality and all combined events. However, no echocardiographic parameter independently predicted cerebrovascular disease or non-cardiovascular events. In conclusion, E/e', s', and LVEDV have independent predictive values for several cardiovascular and mortality events.

Diastolic function is a strong predictor of mortality in patients with chronic kidney disease

Background

Cardiovascular disease is a major cause of death in patients with stage 4–5 Chronic Kidney disease (CKD, eGFR < 30). There are only limited data on the risk factors predicting these complications in CKD patients. Our aim was to determine the role of clinical and echocardiographic parameters in predicting mortality and cardiovascular complications in CKD patients.

Methods

We conducted a prospective observational cohort study of 153 CKD patients between 2007 and 2009. All patients underwent echocardiography at baseline and were followed for a mean of 2.6 years using regular clinic visits and review of files and hospital presentations to record the incidence of cardiovascular events and death.

Results

Of 153 patients enrolled, 57 (37%) were on dialysis and 45 (78%) of these patients were on haemodialysis. An enlarged LV was present in 32% of patients and in 22% the LVEF was below 55%. LV mass index was increased in 75% of patients. Some degree of diastolic dysfunction was present in 85% of patients and 35% had grade 2 or higher diastolic dysfunction. During follow up 41 patients (27%) died, 15 (39%) from cardiovascular causes. Mortality was 24.0% in the non-dialysis patients versus 31.6% in patients on dialysis (p=ns). On multivariate analysis age >75 years, previous history of MI, diastolic dysfunction and detectable serum troponin T were significant independent predictor of mortality (P < 0.01).

Conclusion

Patients with stage 4–5 CKD had a mortality rate of 27% over a mean follow up of 2.6 years. Age >75 years, history of MI, diastolic dysfunction and troponin T were independent predictors of mortality.

Diastolic dysfunction of the left ventricle is associated with pulmonary edema after renal transplantation

BACKGROUND

Post-operative pulmonary complications are associated with high mortality and graft loss in renal transplantation recipients. Left ventricular diastolic dysfunction is not uncommon in patients with chronic renal failure, including those with preserved left ventricular systolic function. The purpose of this study was to determine the relationship between left ventricular diastolic dysfunction and incidence of post-operative pulmonary edema in renal transplantation recipients with preserved left ventricular systolic function.

METHODS

Pre-operative left ventricular function and incidence of pulmonary edema were retrospectively studied in 209 patients who underwent living-donor renal transplantation between January 2010 and October 2012. Left ventricular systolic and diastolic functions were evaluated by ejection fraction and E/E' ratio, retrospectively, using transthoracic echocardiography. Pulmonary edema was defined by evidence of pulmonary congestion on the chest X-ray together with PaO2 /FiO2 ratio < 300 mmHg.

RESULTS

Eleven out of 190 (5.8%) renal transplantation patients with preserved left ventricular systolic function developed post-operative pulmonary edema. Patients with pulmonary edema had a significantly higher geometric mean (95% confidence interval) of E/E' ratio than those without pulmonary edema [17.8 (14.1-22.5) vs. 11.1 (10.6-11.7), P = 0.001].

CONCLUSION

Pre-operative left ventricular diastolic dysfunction correlated with the development of post-operative pulmonary edema in renal transplantation recipients. Meticulous intraoperative volume therapy is important to avoid post-operative pulmonary edema in such patients.

Association of systemic collagen type IV formation with survival among patients undergoing hemodialysis

OBJECTIVE

The 7S domain of collagen type IV (P4NP_7S) assessed in plasma represents systemic collagen type IV formation. The objective of the study was to investigate the association of systemic collagen type IV formation with survival among patients undergoing hemodialysis.

METHODS

We performed an observational cohort study of 371 hemodialysis patients. Plasma P4NP_7S was analyzed using a specific enzyme-linked immunosorbent assay detecting the amino-terminal propeptide of type IV procollagen. Association between categories of plasma P4NP_7S concentrations and survival was initially assessed by Kaplan-Meier analysis, then in an adjusted Cox model.

RESULTS

For hemodialysis patients in the highest category of systemic collagen type IV formation, i.e. plasma P4NP_7S concentrations more than 775 pg/L, an increased risk for death was observed (highest P4NP_7S category vs all other categories, hazard ratio, 1.934; 95% confidence interval, 1.139 to 3.285). Survival analysis showed an increased risk of death in the highest P4NP_7S category compared to the other categories (Chi square 6.903; P = 0.032). Median survival was only 105 days in the highest P4NP_7S category whereas it was 629 days in the medium category, and 905 days in the lowest category. Multivariable-adjusted Cox regression showed increased odds for death with higher age and higher P4NP_7S categories. Systemic collagen type IV formation was associated with plasma concentrations of the collagen IV degradation product C4M (Spearman r = 0.764; P<0.0001) confirming extracellular matrix turnover.

CONCLUSION

Among hemodialysis patients elevated systemic collagen type IV formation suggesting accelerating systemic fibrosis was associated with increased risk of death.

Outcomes after kidney transplantation of patients previously diagnosed with atrial fibrillation

Little is known about the prevalence and outcomes of patients with atrial fibrillation/flutter (AF) who receive a kidney transplant. We identified all patients who had >1 year of uninterrupted Medicare A+B coverage before receiving their first kidney transplant (1997-2009). The presence of pretransplant AF was ascertained from diagnosis codes in Medicare physician claims. We studied the posttransplant outcomes of death, all-cause graft failure, death-censored graft failure and stroke using multivariable Cox regression. Of 62 706 eligible first kidney transplant recipients studied, 3794 (6.4%) were diagnosed with AF prior to kidney transplant. Over a mean follow up of 4.9 years, 40.6% of AF patients and 24.9% without AF died. All-cause and death-censored graft failure were 46.8% and 16.5%, respectively, in the AF group and 36.4% and 19.5%, respectively, in those without AF. Ischemic stroke occurred in 2.8% of patients with and 1.6% of patients without AF. In patients with AF, multivariable-adjusted hazard ratios (95% confidence intervals) for death, graft failure, death-censored graft failure and ischemic stroke were 1.46 (1.38-1.54), 1.41 (1.34-1.48), 1.26 (1.15-1.37) and 1.36 (1.10-1.68), respectively. Pre-existing AF is associated with poor posttransplant outcomes. Special attention should be paid to AF in pretransplant evaluation, counseling and risk stratification of kidney transplant candidates.

Aortic valve prosthesis selection in dialysis patients based on the patient's condition

Previous studies have examined outcomes in dialysis patients undergoing cardiac surgery. However, only a few studies have solely focused on outcomes after aortic valve replacement (AVR). This study aimed to clarify independent predictors of the long-term survival of dialysis patients with AVR and to determine whether a mechanical valve or bioprosthesis is suitable based on the patient's condition. A total of 38 consecutive dialysis patients who underwent AVR at our institute were reviewed (mean age 69.1 ± 9.4 years). There were 23 bioprostheses and 15 mechanical valve replacements. The operative mortality and the long-term survival were not different between the bioprosthesis and the mechanical valve group (13.0 vs. 13.3%). The significant multivariate predictors for long-term survival were concomitant coronary artery bypass grafting (CABG) and prosthesis size. Valve types and age at operation did not affect long-term survival. Five-year survival of patients with small prosthetic valves and concomitant CABG was 0%. When the patient's quality of life is taken into account, it may be appropriate to use a bioprosthesis in a dialysis patient with a small annulus and concomitant CABG even if the patient is young.

Novel imaging techniques for diffuse myocardial fibrosis

Diffuse myocardial fibrosis (DMF) is an important marker in many cardiac diseases, but its utility has been limited by the need for biopsy for its assessment. An accurate noninvasive method for DMF assessment could transform cardiology. This review explores the basic biology of DMF and then discusses the ability of various cardiac imaging modalities to evaluate this variable, speculating on how this area of research may develop over the next few years.

Serum alkaline phosphatase levels and left ventricular diastolic dysfunction in patients with advanced chronic kidney disease

BACKGROUND

High levels of alkaline phosphatase (ALP) have been associated with increased mortality in patients with advanced chronic kidney disease (CKD). We hypothesize that elevated ALP could be partly explained by subclinical liver congestion related to left ventricular diastolic dysfunction.

METHODS

Doppler echocardiography was performed in 68 patients with advanced CKD followed up for a median of 2.1 years. Time-averaged levels of ALP and γ-glutamyl transferase (GGT) were compared between patients with and without diastolic dysfunction. We also evaluated the effect of intensifying diuretic treatment on ALP levels in a small group of 16 patients with high ALP and signs of volume overload.

RESULTS

ALP correlated significantly (p < 0.001) with GGT but not with parathyroid hormone (p = 0.09). Patients with diastolic dysfunction showed higher ALP (p = 0.01), higher GGT (p = 0.03) and lower albumin (p = 0.04). The highest values of ALP were observed in patients with diastolic dysfunction plus pulmonary hypertension (p = 0.01). Intensifying diuretic therapy in a subgroup of patients with signs of fluid overload induced a significant reduction in body weight, GGT (p < 0.001) and ALP levels (p < 0.001).

CONCLUSIONS

Elevated ALP in patients with advanced CKD could be partly explained by subclinical liver congestion related to left ventricular diastolic dysfunction, hypervolemia or both. The worse prognosis of these patients could be explained by their myocardial damage.

Cardiorenal syndrome type 4-cardiovascular disease in patients with chronic kidney disease: epidemiology, pathogenesis, and management

The term cardiorenal syndrome refers to the interaction between the heart and the kidney in disease and encompasses five distinct types according to the initial site affected and the acute or chronic nature of the injury. Type 4, or chronic renocardiac syndrome, involves the features of chronic renal disease (CKD) leading to cardiovascular injury. There is sufficient epidemiologic evidence linking CKD with increased cardiovascular morbidity and mortality. The underlying pathophysiology goes beyond the highly prevalent traditional cardiovascular risk burden affecting renal patients. It involves CKD-related factors, which lead to cardiac and vascular pathology, mainly left ventricular hypertrophy, myocardial fibrosis, and vascular calcification. Risk management should consider both traditional and CKD-related factors, while therapeutic interventions, apart from appearing underutilized, still await further confirmation from large trials.