Prognostic value of cardiac troponin T is independent of inflammation, residual renal function, and cardiac hypertrophy and dysfunction in peritoneal dialysis patients

Prediction of mortality among patients with chronic kidney disease: A systematic review

BACKGROUND

Chronic kidney disease (CKD) is a common medical condition that is increasing in prevalence. Existing published evidence has revealed through regression analyses that several clinical characteristics are associated with mortality in CKD patients. However, the predictive accuracies of these risk factors for mortality have not been clearly demonstrated.

AIM

To demonstrate the accuracy of mortality predictive factors in CKD patients by utilizing the area under the receiver operating characteristic (ROC) curve (AUC) analysis.

METHODS

We searched Ovid MEDLINE, EMBASE, and the Cochrane Library for eligible articles through January 2021. Studies were included based on the following criteria: (1) Study nature was observational or conference abstract; (2) Study populations involved patients with non-transplant CKD at any CKD stage severity; and (3) Predictive factors for mortality were presented with AUC analysis and its associated 95% confidence interval (CI). AUC of 0.70-0.79 is considered acceptable, 0.80-0.89 is considered excellent, and more than 0.90 is considered outstanding.

RESULTS

Of 1759 citations, a total of 18 studies (n = 14579) were included in this systematic review. Eight hundred thirty two patients had non-dialysis CKD, and 13747 patients had dialysis-dependent CKD (2160 patients on hemodialysis, 370 patients on peritoneal dialysis, and 11217 patients on non-differentiated dialysis modality). Of 24 mortality predictive factors, none were deemed outstanding for mortality prediction. A total of seven predictive factors [N-terminal pro-brain natriuretic peptide (NT-proBNP), BNP, soluble urokinase plasminogen activator receptor (suPAR), augmentation index, left atrial reservoir strain, C-reactive protein, and systolic pulmonary artery pressure] were identified as excellent. Seventeen predictive factors were in the acceptable range, which we classified into the following subgroups: predictors for the non-dialysis population, echocardiographic factors, comorbidities, and miscellaneous.

CONCLUSION

Several factors were found to predict mortality in CKD patients. Echocardiography is an important tool for mortality prognostication in CKD patients by evaluating left atrial reservoir strain, systolic pulmonary artery pressure, diastolic function, and left ventricular mass index.

Clinical importance of high- sensitivity troponin T in patients without coronary artery disease

Cardiac troponin is the preferred biomarker for the diagnosis of the acute coronary syndrome (ACS), but many other diseases can be identified with elevated troponin levels in the absence of ACS. The recent development of a high-sensitive cardiac troponin T (hs-cTnT) assay permits the detection of very low levels of cTnT. The use of hs-cTnT assay has emerged as a tool for identifying high-risk individuals for primary preventive treatment and can detect subclinical injury in asymptomatic patients. Hs-cTnT analyses are generally related to ischemia in the literature. Thus, we made an evaluation of hs-cTnT analysis in non-coronary patients, which may contribute to the literature.

The assessment of coronary artery disease in patients with end-stage renal disease

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality among patients with end-stage renal disease (ESRD). Clustering of traditional atherosclerotic and non-traditional risk factors drive the excess rates of coronary and non-coronary CVD in patients with ESRD. Coronary artery disease (CAD) is a key disease process, present in ∼50% of the haemodialysis population ≥65 years of age. Patients with ESRD are more likely to be asymptomatic, posing a challenge to the correct identification of CAD, which is essential for appropriate risk stratification and management. Given the lack of randomized clinical trial evidence in this population, current practice is informed by observational data with a significant potential for bias. For this reason, the most appropriate approach to the investigation of CAD is the subject of considerable discussion, with practice patterns largely varying between different centres. Traditional imaging modalities are limited in their diagnostic accuracy and prognostic value for cardiac events and survival in patients with ESRD, demonstrated by the large number of adverse cardiac outcomes among patients with negative test results. This review focuses on the current understanding of CAD screening in the ESRD population, discussing the available evidence for the use of various imaging techniques to refine risk prediction, with an emphasis on their strengths and limitations.

Does Routine Bioimpedance-Guided Fluid Management Provide Additional Benefit to Non-Anuric Peritoneal Dialysis Patients? Results from COMPASS Clinical Trial

INTRODUCTION

In peritoneal dialysis (PD) patients, volume overload is related to cardiac dysfunction and mortality, while intravascular volume depletion is associated with a rapid decline in the residual renal function (RRF). This study sought to determine the clinical usefulness of bioimpedance spectroscopy (BIS)-guided fluid management for preserving RRF and cardiac function in PD patients.

SUBJECTS AND METHODS

This is a multicenter, prospective, open-label study that was conducted over a 1-year period (NCT01887262). Non-anuric (urine volume > 500 mL/day) subjects on PD were enrolled. Subjects in the control group received fluid management based on the clinical information alone. Those in the BIS group received BIS-guided fluid management along with clinical information.

RESULTS

The subjects (N = 137, mean age 51.3 ± 12.8 years, 54% male) were randomly assigned to the BIS group (n = 67) or to the control group (n = 70). There were no significant differences between the 2 groups with regard to age, sex ratio, cause of kidney failure, duration of PD, baseline comorbidity, RRF, PD method, or peritoneal transport type. At baseline, the 2 groups were not different in terms of RRF (glomerular filtration rate [GFR], 5.1 ± 2.9 vs 5.5 ± 3.7 mL/min/1.73 m²). After follow-up, changes in the GFR between the 2 groups were not different (-1.5 ± 2.4 vs -1.3 ± 2.6 mL/min/1.73 m², p = 0.593). Over the 1-year study period, both groups maintained stability of various fluid status parameters. Between the 2 groups, there were no differences in the net change of various fluid status parameters such as overhydration (OH) and extracellular water/total body water (ECW/TBW). A net change in ECW over 1 year was slightly but significantly higher in the control group (net increase, 0.57 ± 1.27 vs 0.05 ± 1.63 L, p = 0.047). However, this difference was not translated into an improvement in RRF in the BIS group. There were no differences in echocardiographic parameters or arterial stiffness at the end of follow-up.

CONCLUSION

Routine BIS-guided fluid management in non-anuric PD patients did not provide additional benefit in volume control, RRF preservation, or cardiovascular (CV) parameters. However, our study cannot be generalized to the whole PD population. Further research is warranted in order to investigate the subpopulation of PD patients who may benefit from routine BIS-guided fluid management.

Numerical expression of volume status using the bioimpedance ratio in continuous ambulatory peritoneal dialysis patients: A pilot study

BACKGROUND

Volume overload results in higher mortality rates in patients on continuous ambulatory peritoneal dialysis (CAPD). The ratio of bioimpedance (RBI) might be a helpful parameter in adjusting dry body weight in CAPD patients. This study examined whether it is possible to distinguish between non-hypervolemic status and hypervolemic status in CAPD patients by using only RBI.

METHODS

RBI was calculated as follows: RBI = impedance at 50 kHz/impedance at 500 kHz. Based on the experts' judgements, a total of 64 CAPD patients were divided into two groups, a non-hypervolemic group and a hypervolemic group. The RBI was measured from right wrist to right ankle (rw-raRBI) by bioimpedance spectroscopy (BCM®, Fresenius Medical Care) before and after the peritosol was emptied. Other RBIs were measured from the right side of the anterior superior iliac spine to the ipsilateral ankle (rasis-raRBI) to control for the electro-physiological effects of peritoneal dialysate.

RESULTS

The mean rw-raRBI of non-hypervolemic patients was higher than that of hypervolemic patients in the presence (1.141 ± 0.022 vs. 1.121 ± 0.021, P < 0.001) of a peritosol. Likewise, the mean rasis-raRBI of non-hypervolemic patients was higher than that of hypervolemic patients (presence of peritosol: 1.136 ± 0.026 vs. 1.109 ± 0.022, P < 0.001; absence of peritosol: 1.131 ± 0.022 vs. 1.107 ± 0.022, P < 0.001).

CONCLUSION

The volume status of CAPD patients was able to be simply expressed by RBI. Therefore, this study suggests that when patients cannot be analyzed using BCM, RBI could be an alternative.

Overhydration Is a Strong Predictor of Mortality in Peritoneal Dialysis Patients - Independently of Cardiac Failure

Background

Overhydration is a common problem in peritoneal dialysis patients and has been shown to be associated with mortality. However, it still remains unclear whether overhydration per se is predictive of mortality or whether it is mainly a reflection of underlying comorbidities. The purpose of our study was to assess overhydration in peritoneal dialysis patients using bioimpedance spectroscopy and to investigate whether overhydration is an independent predictor of mortality.

Methods

We analyzed and followed 54 peritoneal dialysis patients between June 2008 and December 2014. All patients underwent bioimpedance spectroscopy measurement once and were allocated to normohydrated and overhydrated groups. Overhydration was defined as an absolute overhydration/extracellular volume ratio > 15%. Simultaneously, clinical, echocardiographic and laboratory data were assessed. Heart failure was defined either on echocardiography, as a reduced left ventricular ejection fraction, or clinically according to the New York Heart Association functional classification. Patient survival was documented up until December 31^st 2014. Factors associated with mortality were identified and a multivariable Cox regression model was used to identify independent predictors of mortality.

Results

Apart from higher daily peritoneal ultrafiltration rate and cumulative diuretic dose in overhydrated patients, there were no significant differences between the 2 groups, in particular with respect to gender, body mass index, comorbidity and cardiac medication. Mortality was higher in overhydrated than in euvolemic patients. In the univariate analysis, increased age, overhydration, low diastolic blood pressure, raised troponin and NTproBNP, hypoalbuminemia, heart failure but not CRP were predictive of mortality. After adjustment, only overhydration, increased age and low diastolic blood pressure remained statistically significant in the multivariate analysis.

Conclusions

Overhydration remains an independent predictor of mortality even after adjustment for heart failure in peritoneal dialysis patients and should therefore be actively sought and managed in order to improve survival in this population.

Comparison of bioimpedance spectroscopy and the Watson formula for measuring body volume in patients on peritoneal dialysis

INTRODUCTION

Knowing total body volume (V) is crucial in patients on peritoneal dialysis (PD). It is usually calculated by the Watson anthropometric formula, although the use of bioimpedance spectroscopy (BIS) is becoming increasingly widespread. Measuring V with both methods can at times produce quite different results.

OBJECTIVE

We aimed to identify differences between the 2 forms of measuring volume in a PD unit and determine which clinical factors are associated with these differences.

METHODS

Ours is an observational study of 74 patients on PD. We measured V using BIS (Vbis) and the Watson formula (Vw); 271 measurements were made with each method. We calculated the difference between Vbis and Vw in each patient and classified them into 2 groups: Difference between volumes ≥10% or <10% Vbis. We assessed the presence of several clinical parameters in our patients. We assessed whether there were any differences between Vbis and Vw (Student t-test). We determined whether there was any association between the difference in volumes and the presence of the clinical parameters analysed (chi square test).

RESULTS

V was 2.15 l higher measured by the Watson formula than with BIS (P<.01). In 58.67% of the measurements, the difference between Vbis and Vw was ≥10%. Significant differences were found when comparing the presence of difference between volumes and the presence or not of diabetes mellitus (DM) (p=0,03), hypertension (HTN) (p=0,036), hypoalbuminemia (p<0,01), hypoprealbuminemia (p<0,01), low phase angle at 50 Hz (p<0,01), high C reactive protein (p<0,01), obesity (p=0,027), E/I ratio (ratio between extracellular and intracellular water) ≥1 (p<0.01) and residual diuresis (p=0.029).

CONCLUSIONS

There are significant differences in the V of PD Unit patients when obtained by Watson formula or by BIS. A difference between the measurements is associated with the presence of DM, HTN, hypoalbuminaemia, obesity, malnutrition, inflammation, E/I ratio ≥1 and the absence of residual diuresis.

Which Biomarker is the Best for Predicting Mortality in Incident Peritoneal Dialysis Patients: NT-ProBNP, Cardiac TnT, or hsCRP?: A Prospective Observational Study

Although numerous previous studies have explored various biomarkers for their ability to predict mortality in end-stage renal disease (ESRD) patients, these studies have been limited by retrospective analyses, mostly prevalent dialysis patients, and the measurement of only 1 or 2 biomarkers. This prospective study was aimed to evaluate the association between 3 biomarkers and mortality in incident 335 ESRD patients starting continuous ambulatory peritoneal dialysis (CAPD) in Korea. According to the baseline NT-proBNP, cTnT, and hsCRP levels, the patients were stratified into tertiles, and cardiovascular (CV) and all-cause mortalities were compared. Additionally, time-dependent ROC curves were constructed, and the net reclassification index (NRI) and integrated discrimination improvement (IDI) of the models with various biomarkers were calculated. We found the upper tertile of NT-proBNP was significantly associated with increased risk of both CV and all-cause mortalities. However, the upper tertile of hsCRP was significantly related only to the high risk of all-cause mortality even after adjustment for age, sex, and white blood cell counts. Moreover, NT-proBNP had the highest predictive power for CV mortality, whereas hsCRP was the best prognostic marker for all-cause mortality among these biomarkers. In conclusions, NT-proBNP is a more significant prognostic factor for CV mortality than cTnT and hsCRP, whereas hsCRP is a more significant predictor than NT-proBNP and cTnT for all-cause mortality in incident peritoneal dialysis patients.

Kidney Function Alters the Relationship between Postoperative Troponin T Level and Death

Cardiac troponin T (cTnT), even at low concentrations, is a risk factor for 30-day mortality in patients undergoing noncardiac surgery, but it is uncertain whether that risk is generalizable to patients with poor kidney function. We, therefore, evaluated the relationship between cTnT concentration and kidney function on the outcome of 30-day mortality in a post hoc analysis of a prospective cohort study of patients undergoing noncardiac surgery. cTnT was measured for 3 days after surgery and considered abnormal if the peak was ≥0.02 ng/ml. Of the included 14,037 patients, 267 (1.9%) patients died within 30 days of surgery. The adjusted hazard ratios for death with an abnormal cTnT concentration were 4.37 (95% confidence intervals [95% CI], 3.21 to 6.22), 6.15 (95% CI, 2.95 to 140.9), 6.30 (95% CI, 3.12 to 21.23), 1.33 (95% CI, 0.56 to 4.85), and 1.46 (95% CI, 0.46 to 9.21) for eGFR≥60, 45 to <60, 30 to <45, 15 to <30, and <15 ml/min per 1.73 m(2) or on dialysis, respectively. Compared with patients with eGFR≥60 ml/min per 1.73 m(2), the adjusted hazard ratio was significantly lower for patients with eGFR=15 to <30 ml/min per 1.73 m(2) (interaction P value=0.02). Redefining abnormal cTnT concentration as ≥0.03 ng/ml or a change of ≥0.02 ng/ml did not alter results. Because the risk associated with postoperative cTnT levels may be different for patients with eGFR<30 ml/min per 1.73 m(2), additional research is required to determine how to interpret perioperative cTnT values for patients with low kidney function.

The prognostic value of left ventricular global peak systolic longitudinal strain in chronic peritoneal dialysis patients

Background

Although left ventricular (LV) global systolic longitudinal strain (GLS) reliably and accurately assesses LV systolic function and is also a powerful prognostic predictor, the importance and prognostic value of GLS in end-stage renal disease patients receiving maintenance peritoneal dialysis (PD) remain unclear. This study sought to determine the prognostic value of GLS in chronic PD patients.

Methods

This prospective study collected clinical and echocardiographic data from 106 stable PD patients (50.0 ± 13.9 years, 45% male) in a dialysis unit of a university hospital. These patients were enrolled from April 2010 to June 2010 and followed until August 2013 (follow-up duration 30.3 ± 14.3 months). The primary outcomes were the presence of major adverse events (MAEs), defined as all-cause mortality, and major adverse cardiovascular cerebral events (MACCEs), i.e. cardiovascular death, cardiac hospitalization, and stroke.

Results

Twenty-nine patients (27%) reported a primary outcome. Patients with MAEs had worse LV systolic function (MAEs vs. no MAEs, − 14.8 ± 2.8 vs. − 17.1 ± 2.5%, p = 0.003). Using multivariate Cox regression analyses, being male, having a history of heart failure, diabetes mellitus, an increased pulse pressure (≥ 60 mm Hg), and GLS ≥ − 15% were independent predictors of MAEs. The independent risk factors of MACCEs were a history of diabetes mellitus, an increased pulse pressure, and GLS ≥ − 15%. After comparison of the overall log likelihood χ² of the predictive power, GLS was found to add prognostic information to a model based on traditional risk factors.

Conclusion

GLS ≥ − 15% provided additional prognostic information that allowed for the early identification of high-risk PD patients.

Cardiac troponin I but not cardiac troponin T adheres to polysulfone dialyser membranes in an in vitro haemodialysis model: explanation for lower serum cTnI concentrations following dialysis

BACKGROUND

Elevated serum cardiac troponin T (cTnT) and I (cTnI) can occur in patients with chronic kidney disease. Differences in cTn concentrations between cTnT and cTnI have been reported but the mechanism of such discrepancy has not been investigated. This study investigates the clearance of cTn with the aid of an in vitro model of haemodialysis (HD).

METHODS

Serum was obtained before and after a single session of dialysis from 53 patients receiving HD and assayed for cTnT and cTnI. An in vitro model of the dialysis process was used to investigate the mechanism of clearance of cTn during HD.

RESULTS

Serum cTnI was significantly lower (p=0.043) following a session of HD whereas cTnT concentrations were similar to those obtained before HD. Using an in vitro model of dialysis, it was demonstrated that cTnI is not dialysed from the vascular compartment but adheres to the dialyser membrane.

CONCLUSIONS

The adherence of cTnI to the dialyser membrane is responsible for the observed decrease in serum cTnI following a session of dialysis. The adherence of cTnT or T-I-C complex to the dialyser membrane could not be demonstrated and supports the observation that pre-HD and post-HD serum concentrations of cTnT are similar.

Independent value of cardiac troponin T and left ventricular global longitudinal strain in predicting all-cause mortality among stable hemodialysis patients with preserved left ventricular ejection fraction

Using a speckle-tracking echocardiography (STE), we recently demonstrated that a left ventricular (LV) global longitudinal strain (GLS) ≥ -15% and the serum cardiac troponin T (cTnT) concentration are associated with mortality in stable hemodialysis patients with preserved LV ejection fraction (LVEF). In this study, we explored the relationship between cTnT and echocardiographic parameters and evaluated whether the prognostic value provided by cTnT is independent of a GLS ≥ -15% and vice versa. Eighty-eight stable hemodialysis patients with preserved LVEF were followed for 31 months. STE studies and measurements of cTnT were performed at baseline. CTnT concentration had a modest correlation with GLS (rs = 0.44; P < 0.001) but had a weak or nonsignificant correlation with other echocardiographic parameters. Adjusting for clinical parameters, hazard ratios for each increase of 0.01 ng/mL in cTnT, and a GLS ≥ -15% on mortality were 1.13 (P = 0.009) and 3.09 (P = 0.03) without significant interaction between cTnT and GLS ≥ -15%. In addition, an increased cTnT concentration, a GLS ≥ -15%, or their combination showed significant additional predictive value for mortality when included in models consisting of clinical parameters. Therefore, both cTnT and a GLS ≥ -15% are independent predictors of mortality and are useful for risk stratification.

High-Sensitivity Troponin as a Predictor of Cardiac Events and Mortality in the Stable Dialysis Population

BACKGROUND

High-sensitivity cardiac troponin T (hs-cTnT) is a biomarker used in diagnosing myocardial injury. The clinical utility and the variation of this biomarker over time remain unclear in hemodialysis (HD) and peritoneal dialysis (PD) patients. We sought to determine whether hs-cTnT concentrations were predictive of myocardial infarction (MI) and death and to examine hs-cTnT variability over a 1-year period.

METHODS

A total of 393 nonacute HD and PD patients (70% HD and 30% PD) were followed in a prospective observational study for new MI and death.

RESULTS

Median hs-cTnT was 57 ng/L (interquartile range, 36–101 ng/L) with no observed difference between HD and PD patients (P = 0.11). Incremental increases in mortality (P = 0.024) and MI (P = 0.001) were observed with increasing hs-cTnT quartiles. MI incidence increased significantly across quartiles in both HD and PD patients (P = 0.012 and P = 0.025, respectively), whereas mortality increased only in HD patients (P = 0.015). For every increase of 25 ng/L in hs-cTnT, the unadjusted hazard ratio (HR) was 1.10 for mortality in the whole group (95% CI, 1.04–1.16, P = 0.001) and 1.16 for MI (95% CI, 1.08–1.23, P &lt; 0.001). Adjusted HR for mortality was 1.07 (95% CI, 1.01–1.15, P = 0.04) and 1.14 for MI (95% CI, 1.06–1.22, P &lt; 0.001). Changes in hs-cTnT from baseline concentrations after 1 year were minimal (55 ng/L vs 53 ng/L, P = 0.22) even in patients who had an MI (P = 0.53).

CONCLUSIONS

hs-cTnT appears to have a useful role in predicting MI and death in the dialysis population. Over a 1-year period concentrations remained stable even in patients who sustained a new cardiac event.

Cardiac troponin I in non- acute coronary syndrome patients with chronic kidney disease

Objective

The aim of this study was to assess the results of troponin I (cTnI) in non- acute Coronary Syndrome (ACS) patients with chronic kidney disease (CKD). We also examined the risk factors for elevated cTnI in non-ACS patients with CKD and whether stage 5 CKD modifies the associations of elevated cTnI and the risk factors in non-ACS patients with CKD.

Methods

A retrospective study was performed. Logistic regression models were used.

Results

293 non-ACS patients with CKD were included in the current study. 43.34% non-ACS patients with CKD have an elevated cTnI level and 5.12% have an elevated cTnT level in MI range. In CKD patients without ACS and heart failure, only 26.03% (38/146) patients have an elevated cTnT level. In adjusted analyses, age, diastolic blood pressure and congestive heart failure is associated with an elevated cTnI level in non-ACS patients with CKD. Congestive heart failure is associated with an elevated cTnI level in non-ACS patients with CKD (OR 2.30, 95% CI 1.08,4.88, P=0.03). Stage 5 CKD does not modify the association of congestive heart failure and an elevated cTnI level.

Conclusion

43.34% non-ACS patients with CKD and 26.03% CKD patients without ACS and congestive heart failure have an elevated cTnI level. Congestive heart failure is associated with an elevated cTnI level in non-ACS patients with CKD. Stage 5 CKD does not modify the association of congestive heart failure and an elevated cTnI level.

Diastolic dysfunction and high levels of new cardiac biomarkers as risk factors for cardiovascular events and mortality in hemodialysis patients

BACKGROUND/AIMS

Cardiovascular events (CVEs) are the most frequent cause of death in hemodialysis (HD). We aim to determine cardiovascular and mortality risk factors.

METHODS

A historical cohort study was made of 211 prevalent HD patients [73 (60-80) years, 58% males] between 2005 and 2012. Demographic, laboratory test and echocardiographic values were recorded. During follow-up, CVEs and mortality were documented and analyzed.

RESULTS

94 patients suffered a CVE. Age, history of cardiovascular disease (CVD), peripheral vascular disease, cardiac markers, systolic and diastolic dysfunction (DD) were associated to CVEs. Low albumin (RR 0.414, p = 0.002), DD (1.876, p = 0.038) and previous CVD (3.723, p < 0.001) were identified as independent predictors of CVEs. 98 patients died. Age, a history of CVD, peripheral vascular disease, cardiac markers, DD, dialysis vintage, and a vascular access different from autologous fistulae were associated to mortality. Low albumin (RR 0.499, p = 0.046), DD (RR 2.414, p = 0.017) and a vascular access different from autologous fistulae (RR 2.058, p = 0.034) were independent predictors of mortality.

CONCLUSIONS

DD is an emergent risk factor for death and CVEs in dialysis. Low albumin is also a predictor for CVE. Non-autologous fistulae and low albumin are predictors for death. Nt-proBNP and hsTnT offer good information for identifying high-risk patients, but they do not predict events independently as they are only cardiac damage markers.

Heart failure with preserved or reduced ejection fraction in patients treated with peritoneal dialysis

BACKGROUND

Heart failure is one of the most frequent complications in dialysis patients. However, little is known of the significance of the entity "heart failure with preserved ejection fraction" (HFPEF) in this population. This study aimed to determine the prevalence, clinical profiles, and long-term outcomes of peritoneal dialysis patients with HFPEF.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

220 patients treated with peritoneal dialysis were recruited from a university teaching hospital in Hong Kong.

PREDICTOR

Heart failure was defined clinically based on the presence of: (1) symptoms and signs, including dyspnea, increased jugular venous pressure, and basal crepitations; (2) radiographic evidence of pulmonary venous congestion or interstitial edema; and (3) resolution of symptoms, signs, and radiographic changes with hypertonic peritoneal dialysis exchanges. Based on a combination of clinical history of heart failure and echocardiography-derived ejection fraction, patients were classified as having no heart failure, HFPEF, and heart failure with reduced ejection fraction (HFREF).

OUTCOMES

All-cause mortality, cardiac death, heart failure, and fatal or nonfatal cardiovascular events.

MEASUREMENTS

All patients underwent 2-dimensional echocardiography and tissue Doppler imaging at baseline and were followed up prospectively for clinical events for 4 years.

RESULTS

86 (39%) patients had heart failure, of whom 54.7% had preserved ejection fraction ≥50% and 45.3% had reduced ejection fraction <50%. Patients with HFPEF were intermediate between those with no heart failure and those with HFREF in terms of blood pressure, prevalence of coronary artery disease, diabetes, cardiac biomarkers, left ventricular mass, volume, and ratio of early mitral inflow velocity to peak mitral annulus velocity. In the multivariable Cox regression analysis, patients with HFPEF showed an increased adjusted HR for cardiac death (2.57; 95% CI, 1.20-5.50), heart failure (HR, 2.25; 95% CI, 1.28-3.96), and fatal or nonfatal cardiovascular event (HR, 2.01; 95% CI, 1.26-3.21) compared with those with no heart failure, but the risk was lower compared with those with HFREF.

LIMITATIONS

The study included prevalent peritoneal dialysis patients and may introduce survival bias.

CONCLUSIONS

HFPEF is common in peritoneal dialysis patients (∼55% of all heart failure) and is associated with increased risk of mortality and adverse cardiovascular outcomes compared with those with no heart failure, although the risk was lower than in patients with HFREF. This entity needs to be more recognized in peritoneal dialysis patients.

Association of cardiac troponin T with left ventricular structure and function in CKD

BACKGROUND

Serum cardiac troponin T (cTnT) is associated with increased risk of heart failure and cardiovascular death in several population settings. We evaluated associations of cTnT levels with cardiac structural and functional abnormalities in a cohort of patients with chronic kidney disease (CKD) without heart failure.

STUDY DESIGN

Cross-sectional.

SETTING & PARTICIPANTS

Chronic Renal Insufficiency Cohort (CRIC; N=3,243).

PREDICTOR

The primary predictor was cTnT level. Secondary predictors included demographic and clinical characteristics, hemoglobin level, high-sensitivity C-reactive protein level, and estimated glomerular filtration rate using cystatin C.

OUTCOMES

Echocardiography was used to determine left ventricular (LV) mass and LV systolic and diastolic function.

MEASUREMENTS

Circulating cTnT was measured in stored sera using the highly sensitive assay. Logistic and linear regression models were used to examine associations of cTnT level with each echocardiographic outcome.

RESULTS

cTnT was detectable in 2,735 (84%) persons; median level was 13.3 (IQR, 7.7-23.8) pg/mL. Compared with undetectable cTnT (<3.0 pg/mL), the highest quartile (23.9-738.7 pg/mL) was approximately 2 times as likely to have LV hypertrophy (OR, 2.43; 95% CI, 1.44-4.09) in the fully adjusted model. cTnT level had a more modest association with LV systolic dysfunction; as a log-linear variable, a significant association was present in the fully adjusted model (OR of 1.4 [95% CI, 1.2-1.7] per 1-log unit; P < 0.001). There was no significant independent association between cTnT level and LV diastolic dysfunction. When evaluated as a screening test, cTnT level functioned only modestly for LV hypertrophy and concentric hypertrophy detection (area under the curve, 0.64 for both), with weaker areas under the curve for the other outcomes.

LIMITATIONS

The presence of coronary artery disease was not formally assessed using either noninvasive or angiographic techniques in this study.

CONCLUSIONS

In this large CKD cohort without heart failure, detectable cTnT had a strong association with LV hypertrophy, a more modest association with LV systolic dysfunction, and no association with diastolic dysfunction. These findings indicate that circulating cTnT levels in patients with CKD are predominantly an indicator of pathologic LV hypertrophy.

Biomarkers in hemodialysis patients

Patients with chronic kidney disease (CKD) are, compared to the general population, at higher risk of cardiovascular disease (CVD), including sudden death, coronary artery disease (CAD), congestive heart failure (HF), stroke, and peripheral artery disease. The presence of CVD is independently associated with kidney function decline. Renal insufficiency is a strong and independent predictor of mortality in patients with different CKD stages. The interplay of traditional and nontraditional risk factors is complex such that risk factor profiles are different in CKD patients. Seemingly, paradoxical associations between traditional risk factors and cardiovascular outcome complicate efforts to identify real cardiovascular etiology in these patients. Additional tools are often required to aid clinical assessment of cardiovascular risk. Recently, a number of cardiovascular biomarkers were identified as predictors of outcome in CVD. These may be used to guide early diagnosis and therapy for CVD or may predict outcome in CKD. This review focuses on the potential diagnostic and prognostic use of some important new biomarkers including brain natriuretic peptide (BNP), cardiac troponins (cTns), inflammatory markers, adhesion molecules, and asymmetric dimethylarginine (ADMA) in CKD as well as those patients with end-stage renal failure.

Prognostic value of highly sensitive troponin T on cardiac events in patients with chronic kidney disease not on dialysis

Serum troponin T levels using a highly sensitive assay (hsTnT) in patients with chronic kidney disease (CKD) not on dialysis have not been examined. The aim of this prospective cohort study was to investigate the association of hsTnT with cardiac events in ambulatory CKD patients not on dialysis. The serum hsTnT level was measured in 442 ambulatory CKD patients not on dialysis whose estimated glomerular filtration rate was <60 ml/min/1.73 m(2). Patients were divided into quartiles according to hsTnT levels, and were followed up for 3 years. Cardiac events were defined as a cardiac death, acute myocardial infarction, unstable angina pectoris that required emergency coronary revascularization, or hospitalization for worsening heart failure. During the follow-up period (median 22 months), 63 cardiac events occurred. Kaplan-Meier incidence rates of cardiac events for 3 years were 0.88 %, 11.5 %, 19.0 %, and 41.4 % among quartiles of hsTnT levels (P < 0.0001). After adjusting for other confounders, elevated hsTnT level was an independent predictor for cardiac events (hazard ratio 6.18, 95 % confidence interval 1.38-27.7, P = 0.0080 for highest quartile vs lowest quartile). In addition, C-index for receiver-operating characteristic curves for cardiac events was greater in an established risks plus hsTnT model than in the established risk alone model (0.857 vs 0.844, P = 0.026). Using a highly sensitive assay, serum hsTnT level was shown to be an independent predictor of cardiac events and a promising risk stratification tool in patients with CKD not on dialysis.

Fibroblast growth factor 23, high-sensitivity cardiac troponin, and left ventricular hypertrophy in CKD

BACKGROUND

Detectable levels of cardiac troponins are common in individuals with chronic kidney disease (CKD), even in the absence of symptomatic cardiovascular disease. Abnormal cardiac troponin values are associated with coronary artery disease and left ventricular hypertrophy (LVH) and predict poor clinical outcomes. Elevated levels of fibroblast growth factor 23 (FGF-23) contribute to LVH in CKD. We investigated the association of FGF-23 and hs-cTnI (high-sensitivity cardiac troponin I) and hs-cTnT (high-sensitivity cardiac troponin T) levels in CKD and examined the role of LVH in this association.

STUDY DESIGN

Cross-sectional observational study.

SETTING & PARTICIPANTS

153 stable outpatients with non-dialysis-dependent CKD.

PREDICTOR

The primary predictor was FGF-23 level.

OUTCOMES

hs-cTnI, hs-cTnT.

MEASUREMENTS

FGF-23, hs-cTnI, hs-cTnT; left ventricular mass index (LVMI) assessed by echocardiography; coronary artery calcification (CAC) measured by computed tomography. LVMI and CAC were evaluated as potential mediators of the effect of FGF-23 on hs-cTnI/T.

RESULTS

Mean age was 64 ± 12 (SD) years, mean estimated glomerular filtration rate was 34 ± 11 mL/min/1.73 m(2), median FGF-23 level was 120 (25th-75th percentile, 79-223) reference unit (RU)/mL, median hs-cTnI level was 6.5 (25th-75th percentile, 3.5-14.5) pg/mL, and median hs-cTnT level was 16.8 (25th-75th percentile, 11.1-33.9) pg/mL. cTnI and cTnT concentrations were higher than the 99th percentile of a healthy population in 42% and 61% of patients, respectively. In unadjusted and multivariable-adjusted analyses, hs-cTnI/T levels were associated significantly with FGF-23 levels. Adjusting for LVMI, but not CAC, weakened the association of FGF-23 and hs-cTnI/T levels.

LIMITATIONS

Vitamin D levels were not measured. The prevalence of coronary artery disease may have been underestimated because it was ascertained by self-report.

CONCLUSIONS

Minimally elevated cTnI and cTnT levels, detectable by high-sensitivity assays, are associated with elevated FGF-23 levels in stable outpatients with CKD. FGF-23-associated LVH may contribute to detectable hs-cTnI/T levels observed in non-dialysis-dependent patients with CKD.

Fluid status in peritoneal dialysis patients: the European Body Composition Monitoring (EuroBCM) study cohort

BACKGROUND

Euvolemia is an important adequacy parameter in peritoneal dialysis (PD) patients. However, accurate tools to evaluate volume status in clinical practice and data on volume status in PD patients as compared to healthy population, and the associated factors, have not been available so far.

METHODS

We used a bio-impedance spectroscopy device, the Body Composition Monitor (BCM) to assess volume status in a cross-sectional cohort of prevalent PD patients in different European countries. The results were compared to an age and gender matched healthy population.

RESULTS

Only 40% out of 639 patients from 28 centres in 6 countries were normovolemic. Severe fluid overload was present in 25.2%. There was a wide scatter in the relation between blood pressure and volume status. In a multivariate analysis in the subgroup of patients from countries with unrestricted availability of all PD modalities and fluid types, older age, male gender, lower serum albumin, lower BMI, diabetes, higher systolic blood pressure, and use of at least one exchange per day with the highest hypertonic glucose were associated with higher relative tissue hydration. Neither urinary output nor ultrafiltration, PD fluid type or PD modality were retained in the model (total R² of the model = 0.57).

CONCLUSIONS

The EuroBCM study demonstrates some interesting issues regarding volume status in PD. As in HD patients, hypervolemia is a frequent condition in PD patients and blood pressure can be a misleading clinical tool to evaluate volume status. To monitor fluid balance, not only fluid output but also dietary input should be considered. Close monitoring of volume status, a correct dialysis prescription adapted to the needs of the patient and dietary measures seem to be warranted to avoid hypervolemia.

Incremental value of a combination of cardiac troponin T, N-terminal pro-brain natriuretic peptide and C-reactive protein for prediction of mortality in end-stage renal disease

OBJECTIVE

To determine the relative prognostic merits of C-reactive protein (CRP), cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) for prediction of all-cause death in patients with end-stage renal disease (ESRD) receiving haemodialysis.

MATERIAL AND METHODS

This prospective, controlled cohort study included 109 patients. Biomarkers were sampled at inclusion and considered as categorical and continuous variables in Cox proportional hazard models.

RESULTS

Mean follow-up ± SD was 926 ± 385 days, during which 52 patients (48%) died. All three markers were predictive of death in univariate analysis. In multivariable analysis, elevated cTnT (> 0.01 μg/l) and CRP (> 1.0 mg/dl) remained significantly associated with mortality [hazard ratio (95% confidence interval), 3.2 (1.2-8.5), p = 0.017 for cTnT; 2.0 (1.0-3.8), p = 0.032 for CRP], while NT-pro-BNP lost independent prognostic power. Addition of cTnT and CRP to established risk factors significantly improved the global fit of the model (p < 0.001), increased the c statistic from 0.726 to 0.758 and significantly increased the integrated discrimination improvement (p < 0.001).

CONCLUSION

The results suggest that cTnT and CRP can be used in combination for risk stratification in patients with ESRD and highlight the additive effect they confer in this regard.

Effect of spironolactone on left ventricular systolic and diastolic function in patients with early stage chronic kidney disease

Patients with early chronic kidney disease (CKD) have an increased risk for cardiovascular disease. Aldosterone levels are elevated and might impair ventricular function through adverse myocardial and vascular proinflammatory and fibrotic effects. In the Chronic Renal Impairment in Birmingham II (CRIB II) study, it was hypothesized that mineralocorticoid receptor blockade with spironolactone in addition to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers would improve left ventricular (LV) function and markers of inflammation, ventricular stretch, and collagen turnover in early CKD. A total of 112 patients with early CKD were randomized to spironolactone 25 mg/day or placebo for 40 weeks. Ventricular function was assessed by echocardiography and cardiac magnetic resonance imaging tagging. High-sensitivity C-reactive protein, N-terminal-pro-B-type natriuretic peptide, and aminoterminal propeptide of type III procollagen were measured. Spironolactone improved LV long-axis systolic function (Sm 8.2 ± 1.4 vs 7.7 ± 1.3 cm/s, p <0.05), torsion (7.77 ± 1.61° vs 6.77 ± 1.48°, p <0.05), and myocardial deformation (strain rate -1.14 ± 0.24 vs -1.09 ± 0.20 s(-1), p <0.05) compared to placebo, without a change in the ejection fraction. Markers of LV relaxation (E/e' ratio 7.2 ± 2.3 vs 8.5 ± 2.3, p <0.05) and suction (M-mode propagation velocity 56 ± 12 vs 50 ± 12 cm/s, p <0.05) were also improved. Spironolactone reduced N-terminal-pro-B-type natriuretic peptide (24.8 pmol/L [range 0.4 to 122.4] vs 39.4 pmol/L [range 10.8 to 102.4], p <0.01) and attenuated an increase in aminoterminal propeptide of type III procollagen observed with placebo. In conclusion, spironolactone improves markers of regional LV systolic and diastolic function in early CKD.

Current perspectives on diagnosis of heart failure in long-term dialysis patients

Cardiovascular disease is highly prevalent in patients with chronic kidney failure treated using dialysis. The risk of cardiovascular events is estimated to be at least 2- to 10-fold higher in dialysis patients than in age-, race-, and sex-matched persons with normal kidney function. A significant proportion of cardiovascular events in long-term dialysis patients is caused by heart failure, and the presence of heart failure is predictive of a poor prognosis. Despite the significant morbidity and mortality associated with heart failure, very few therapeutic options are proved to prevent and treat the progression of this complication in dialysis patients. There are several potential reasons for this, chiefly reflecting both challenges with diagnosis due to the coexistence of volume overload and a paucity of adequately powered prospective randomized controlled trials that examine the efficacy of different therapeutic options in dialysis patients with cardiac disease or heart failure. Thus, unlike in the general population, very few advances have been made in managing this severe complication in dialysis patients. In this article, an overview of the prevalence, severity, and risk factors for heart failure in maintenance dialysis patients is provided and the diagnosis of heart failure in these patients is revisited.

How does volume status affect BNP and troponin levels as markers of cardiovascular status in peritoneal dialysis?

Cardiac biomarkers such as brain natriuretic peptide, amino-terminal pro-B-type natriuretic peptide (NT-proBNP), and cardiac troponin provide information on cardiovascular morbidity and mortality in patients with normal renal function. In a considerable number of chronic hemodialysis patients, both biomarkers-NT-proBNP and troponin-are elevated despite the absence of cardiac ischemia. The elevation of cardiac biomarkers in chronic hemodialysis patients is of prognostic value with respect to cardiovascular morbidity and mortality. Furthermore, they can serve as tools for volume assessment for optimization of the fluid management aspect of dialysis. However, the association of both these markers in peritoneal dialysis is not clear. Therefore, the authors reviewed the literature to examine the role of these markers in peritoneal dialysis patients both as prognostic indicators as well as tools for volume assessment.

Emerging biomarkers for evaluating cardiovascular risk in the chronic kidney disease patient: how do new pieces fit into the uremic puzzle?

Premature cardiovascular disease (CVD), including stroke, peripheral vascular disease, sudden death, coronary artery disease, and congestive heart failure, is a notorious problem in patients with chronic kidney disease (CKD). Because the presence of CVD is independently associated with kidney function decline, it appears that the relationship between CKD and CVD is reciprocal or bidirectional, and that it is this association that leads to the vicious circle contributing to premature death. As randomized, placebo-controlled trials have so far been disappointing and unable to show a survival benefit of various treatment strategies, such a lipid-lowering, increased dialysis dose and normalization of hemoglobin, the risk factor profile seems to be different in CKD compared with the general population. Indeed, seemingly paradoxical associations between traditional risk factors and cardiovascular outcome in patients with advanced CKD have complicated our efforts to identify the real cardiovascular culprits. This review focuses on the many new pieces that need to be fit into the complicated puzzle of uremic vascular disease, including persistent inflammation, endothelial dysfunction, oxidative stress, and vascular ossification. Each of these is not only highly prevalent in CKD but also more strongly linked to CVD in these patients than in the general population. However, a causal relationship between these new markers and CVD in CKD patients remains to be established. Finally, two novel disciplines, proteomics and epigenetics, will be discussed, because these tools may be helpful in the understanding of the discussed vascular risk factors.