Cardiac biomarkers and survival in haemodialysis patients

NT-pro BNP level at dialysis initiation is a useful biomarker for predicting hospitalization for ischemic heart disease

BACKGROUND

Patients with end-stage kidney disease (ESKD) are at high risk of cardiovascular disease including stroke, heart failure, and ischemic heart disease (IHD). To prevent the occurrence and progression of CVD, a reliable prognostic cardiac biomarker is essential. We investigated the prognostic value of NT-proBNP for each incident type of CVD.

METHODS

Male patients from the Ibaraki Dialysis Initiation Cohort (iDIC) study with preserved serum samples from dialysis initiation day (n = 212) were analyzed. Patients were classified into four groups according to quartiles of baseline NT-pro BNP levels. The relationship between NT-proBNP levels at the initiation of dialysis and the subsequent incidence of hospitalization events due to IHD, heart failure, and stroke was analyzed.

RESULTS

The incidence rate for hospitalization due to IHD was significantly higher in the highest NT-proBNP category (Log rank p = 0.008); those of stroke and heart failure showed no significant differences among quartiles. Cox proportional hazards regression analysis revealed that serum NT-proBNT was the only prognostic factor for hospitalization for IHD after adjustment by major known IHD risk factors. (HR, 1.008; 95% confidence interval, 1.002-1.014; p = 0.01) The ROC curve analysis for the incidence of hospitalization due to IHD showed that NT-proBNP had an area under the curve (AUC) of 0.759 (95% CI 0.622-0.897; p = 0.004) at a cut-off value of 956.6 pg/mL.

CONCLUSION

NT-proBNP measurement at the initiation of dialysis therapy is useful to predict later hospitalization for IHD.

TRIAL REGISTRATION

UMIN000010806.

Myocardial markers are highly altered by higher rates of fluid removal during hemodialysis

INTRODUCTION

Although hemodialysis is lifesaving in patients with kidney failure extensive interdialytic weight gain (IDWG) between dialyses worsens the prognosis. We recently showed a strong correlation between IDWG and predialytic values of cardiac markers. The aim of the present study was to evaluate if the cardiac markers N-terminal pro-B-type natriuretic peptide (proBNP) and troponin T were influenced by IDWG and speed of fluid removal (ultrafiltration-rate).

METHODS

Twenty hemodialysis patients performed in total 60 hemodialysis (three each). Predialytic values of proBNP and troponin T and changes from predialysis to 180 min hemodialysis (180-0 min) were compared with the IDWG calculated in percent of body weight. The ultrafiltration-rate was adjusted (UF-rateadj ) to IDWG: (100 × weight gain between dialysis [kg])/(estimated body dry weight [kg] × length of hemodialysis session [hours]).

RESULTS

UF-rateadj correlated (Spearman) with (1) predialytic values of IDWG (r = 0.983, p < 0.001), proBNP (r = 0.443, p < 0.001), and troponin T (r = 0.296, p = 0.025); and (2) differences in proBNP180-0min (r = 0.572, p < 0.001) and troponin T180-0min (r = 0.400, p = 0.002). UF-ratesadj above a breakpoint of 0.60 caused more release of proBNP180-0min (p = 0.027). Remaining variables in multiple regression analysis with ProBNP180-0min as dependent factor were predialytic proBNP (p < 0.001) and the ultrafiltration-rate (p < 0.001).

CONCLUSION

Higher UF-rateadj during dialysis was correlated to increased levels of cardiac markers. Data support a UF-rateadj lower than 0.6 to limit such increase. Further studies may confirm if limited fluid intake and a lower UF-rateadj should be recommended to prevent cardiac injury during dialysis.

Chronic Kidney Disease Associated with Ischemic Heart Disease: To What Extent Do Biomarkers Help?

Chronic kidney disease represents a complex and multifaceted pathology characterized by the presence of structural or functional renal anomalies associated with a persistent reduction in renal function. As the disease progresses, complications arise due to the chronic inflammatory syndrome, hydro-electrolytic disorders, and toxicity secondary to the uremic environment. Cardiovascular complications are the leading cause of death for these patients. Ischemic cardiac pathology can be both a consequence and complication of chronic kidney disease, highlighting the need to identify specific cardiorenal dysfunction biomarkers targeting pathophysiological mechanisms common to both conditions. This identification is crucial for establishing accurate diagnoses, prognoses, and risk stratifications for patients. This work is intended to elucidate the intricate relationship between chronic kidney disease and ischemic heart disease and to investigate the roles of cardiorenal biomarkers, including cardiac troponin, natriuretic peptides, galectin-3, copeptin, fibroblast growth factor 23 and its co-receptor Klotho, soluble suppression of tumorigenicity 2, and plasma growth differentiation factor 15.

Walking Ability and Brain Natriuretic Peptide Are Highly Predictive of Kidney Transplant Waiting List Removal

Kidney transplant waitlist management is complex because waiting time is long, and the patients have significant comorbidities. Identification of patients at highest risk for waiting list removal for death and medical complications could allow better outcomes and allocation of resources.

Methods

Demographics, functional and frailty assessment' and biochemical data were retrospectively analyzed on 313 consecutive patients listed for kidney transplant. Troponin, brain natriuretic peptide, components of the Fried frailty metrics, pedometer activity, and treadmill ability were measured at the time of transplant evaluation and at subsequent re-evaluations. Cox proportional hazards models were used to identify factors associated with death or waiting list removal for medical reasons. Multivariate models were created to identify significant predictor sets.

Results

Among 249 patients removed while waitlisted, 19 (6.1%) died and 51 (16.3%) were removed for medical reasons. Mean follow-up duration was 2.3 y (±1.5 y). 417 sets of measurements were collected. Significant (P < 0.05) non-time-dependent variables associated with the composite outcome identified on univariate analysis included N-terminal probrain natriuretic peptide (BNP), treadmill ability, pedometer activity, diagnosis of diabetes and the Center of Epidemiological Studies Depression Scale question asking how many days per week could you not get going. Significant time-dependent factors included BNP, treadmill ability, Up and Go, pedometer activity, handgrip, 30 s chair sit-stand test, and age. The optimal time-dependent predictor set included BNP, treadmill ability, and patient age.

Conclusions

Changes in functional and biochemical markers are predictive of kidney waitlist removal for death and medical reasons. BNP and measures of walking ability were of particular importance.

Changes in total and segmental extracellular and intracellular volumes with hypotension during hemodialysis measured with bioimpedance spectroscopy

BACKGROUND

Bioelectrical impedance analysis (BIA) devices have been advocated to guide volume management in hemodialysis (HD) patients. We hypothesized that understanding the dynamics of fluid shifts in different body segments may provide additional insight on preventive measures to reduce the risk of intradialytic hypotension.

METHODS

A prospective observational study was conducted among 42 HD patients at risk of hypotension who were admitted as emergencies inpatient.

RESULTS

A total of 191 BIA measurements were made during the 42 HD sessions, and hypotension occurred during 52 measurements (27%). The extracellular water (ECW) to intracellular water ratio (EIR) was measured in different body segments and declined significantly only in the non-access arm with increasing HD session duration (β = -0.04; 95% confidence interval (CI): -0.05 to -0.03, p < 0.01). There was no significant association between EIR and hypotension with respect to the different body segments. Only pre-HD N-terminal-pro b-type natriuretic peptide was significantly associated with hypotension (β = 0.20, 95% CI: 0.04 to 0.89, p = 0.04). There was no association between relative blood volume monitoring change and EIR.

CONCLUSION

In summary, we found that segmental BIA during HD was unable to detect or predict hypotension during dialysis. Although BIA is able to provide information about ECW and guide clinical assessment of volume in HD patients prior to dialysis, our findings did not suggest the use of serial measurements of changes in EIR in different body segments during HD provided sufficient information to predict intradialytic hypotension. Similarly, changes in EIR did not provide information on changes in plasma volume that could potentially trigger interventions to prevent or reduce intra-dialytic hypotension.

N-terminal pro brain natriuretic peptide predicts both all-cause and cardiovascular disease mortality in Japanese hemodialysis patients

BACKGROUND

The association between N-terminal pro brain natriuretic peptide (NT-proBNP) level and long-term mortality in Japanese hemodialysis patients has not been fully assessed.

METHODS

This prospective, multicenter study included 1428 hemodialysis outpatients. Baseline NT-proBNP levels were measured at the first hemodialysis session of the week and participants were followed for 5 years. The areas under the curve were calculated from receiver operating characteristic curves. Groups determined by quartiles of baseline NT-proBNP level were assessed by the Kaplan-Meier method and log-rank test. The association between NT-proBNP level and mortality was assessed using multivariate Cox proportional hazards models.

RESULTS

During the 5-year follow-up, we observed 370 deaths and 256 censored cases. The areas under the curve of pre-hemodialysis NT-proBNP for all-cause mortality and cardiovascular disease mortality after 1 year were 0.75 and 0.78, respectively, and significantly greater than the areas under the curve at the 3- and 5-year follow-up. Cut-off values for all-cause mortality and cardiovascular disease mortality after 1 year were 4550 and 5467 ng/L, respectively (sensitivity: 82% and 81%; specificity: 59% and 64%). Kaplan-Meier survival analysis showed that the group with pre-hemodialysis NT-proBNP ≥ 8805 ng/L had increased all-cause mortality (P < 0.001) and cardiovascular disease mortality (P < 0.001). Finally, multivariate Cox analysis showed that NT-proBNP level was associated with all-cause mortality (P < 0.001) and cardiovascular disease mortality (P = 0.004) independently from other clinical parameters.

CONCLUSION

NT-proBNP is a useful marker to predict both all-cause and cardiovascular disease mortality in hemodialysis patients.

NT-pro-BNP as marker for cardiac strain that may be caused by high-output arteriovenous shunting in a haemodialysis patient. A case report

BACKGROUND

An arteriovenous fistula (AVF) is the first choice when considering access for haemodialysis (HD). When a forearm AVF fails an upper arm AVF is a frequent subsequent dialysis access option. The latter may cause cardiac strain. NT-pro-B-type natriuretic peptide (NT-NT-proBNP) is a marker used to estimate volume overload and cardiac strain. This case report shows the benefit of using longitudinal individual follow-up of pre-dialysis NT-proBNP in clinical practice to detect changes in cardiac condition that may be due to high-output AVF.

CASE PRESENTATION

An 18 years old patient performed HD via an upper arm AVF before he was admitted to our unit. NT-proBNP was above the upper detection level of 70,000 ng/L. Echocardiography revealed a left-ventricular cardiac insufficiency. Interdialytic weight gain (IDWG) was above 5%. He was instructed to lower fluid intake and IDWG towards 2%. Four months later NT-proBNP surpassed 70,000 ng/L again. Flow in the brachial artery was at 3034 ml/min. Reconstructive surgery of the AVF did not reduce flow and NT-proBNP in the long run. Clinically, he worsened to NYHA class III-IV. It was decided to close the upper arm AVF and to replace it with a lower arm AVF leading to a reduced artery flow of 1344 mL/min. The clinical condition successively recovered and NT-proBNP decreased to 7000 ng/L.

CONCLUSIONS

Pre-dialysis NT-proBNP should be considered as a suitable routine marker for cardiac strain such as caused by high-output AVF besides variables such as IDWG. Brachial artery flow besides AVF flow measurement is helpful.

Interdialytic weight gain of less than 2.5% seems to limit cardiac damage during hemodialysis

Aims:

To investigate if a single low-flux HD induces a rise in cardiac biomarkers and if a change in clinical approach may limit such mechanism.

Material and methods:

A total of 20 chronic HD patients each underwent three different study-dialyses. Dialyzers (low-flux polysulfone, 1.8 sqm) had been stored either dry or wet (Wet) and the blood level in the venous chamber kept low or high. Laboratory results were measured at baseline, 30 and 180 min, adjusted for the effect of fluid shift. Ultrasound measured microemboli signals (MES) within the return line.

Results:

Hemodialysis raised cardiac biomarkers (p < 0.001): Pentraxin 3 (PTX) at 30 min (by 22%) and at 180 min PTX (53%), Pro-BNP (15%), and TnT (5%), similarly for all three HD modes. Baseline values of Pro-BNP correlated with TnT (rho = 0.38, p = 0.004) and PTX (rho = 0.52, p < 0.001). The changes from pre- to 180 min of HD (delta-) were related to baseline values (Pro-BNP: rho = 0.91, p < 0.001; TnT: rho = 0.41, p = 0.001; PTX: rho = 0.29, p = 0.027). Delta Pro-BNP (rho = 0.67, p < 0.001) and TnT (rho = 0.38, p = 0.004) correlated with inter-dialytic-weight-gain (IDWG). Biomarkers behaved similarly between the HD modes. The least negative impact was with an IDWG ⩽ 2.5%. Multiple regression analyses of the Wet-High mode does not exclude a relation between increased exposure of MES and factors such as release of Pro-BNP.

Conclusion:

Hemodialysis, independent of type of dialyzer storage, was associated with raised cardiac biomarkers, more profoundly in patients with higher pre-dialysis values and IDWG. A limitation in IDWG to <2.5% and prolonged ultrafiltration time may limit cardiac strain during HD, especially in patients with cardiovascular risk.

Do Natriuretic Peptide Measurements Provide Insights into Management of End-Stage Renal Disease Patients Undergoing Dialysis?

PURPOSE OF REVIEW

Impaired renal function may affect natriuretic peptide levels through a variety of factors and mechanisms, such as high prevalence of concomitant vascular and myocardial diseases, reduced clearance, increased risk of volume overload, and different types and solute removal techniques in the setting of dialysis. Nevertheless, accumulating evidence suggests that natriuretic peptide testing may provide insights into management of patients with chronic kidney disease (CKD) and end-stage kidney disease (ESRD) on dialysis, as they have been shown to be independently associated with morbidity and mortality.

RECENT FINDINGS

Rising natriuretic peptide levels over time may identify CKD patients more likely to approach ESRD and requiring dialysis initiation. Moreover, serial natriuretic peptide measurements may also be helpful in guiding fluid management in ESRD patients on dialysis. However, since patients with CKD usually have significantly higher and more variable baseline levels of natriuretic peptides than those without CKD, traditional cut-off values may not be applicable, and individualized trajectories should be applied and interpreted in the clinical context. Routine clinical use natriuretic peptide testing in the CKD and ESRD settings still needs to be refined and individualized, yet their diagnostic and prognostic values can provide valuable insights into clinical trajectories and potential treatment responses.

[Natriuretic peptides in dialysis: From theory to clinical practice]

Cardiologists and emergency-wards physicians are used to check natriuretic peptides serum level, mainly B-type natriuretic peptide and N-terminal pro-Brain natriuretic peptide for acute cardiac failure diagnosis. Due to their accumulation in chronic kidney disease and their elimination by dialysis, natriuretic peptides sampling remains debatable in chronic kidney disease patients. In dialysis patients, high natriuretic peptides values are associated with mortality, left ventricular hypertrophy and cardiac failure. However, a single value cannot provide a reliable diagnosis. Our clinical practice is as follows: First, we prefer B-type natriuretic peptide to N-terminal pro-Brain natriuretic peptide because of its shorter half-life, with less impact of renal function and dialysis, making its interpretation easier in case of advanced chronic kidney disease or in dialysis patients; second, we define a reference value of B-type natriuretic peptide at dry weight from serial measurements; third, the B-type natriuretic peptide changes are interpreted according to extracellular fluid and cardiac status, but also from the arteriovenous fistula blood flow. In stable dialysis patients, B-type natriuretic peptide is sampled monthly and weekly in unstable patients. We illustrate our experience using clinical cases of overhydration, new cardiac disease onset, hypovolemia and arteriovenous fistula with high blood flow. Longitudinal follow-up of B-type natriuretic peptide is an important advance in dialysis patients in order to detect and treat extracellular fluid variations and cardiac disease status early, both important factors associated with hard outcomes.

Association of NT-proBNP and BNP With Future Clinical Outcomes in Patients With ESKD: A Systematic Review and Meta-analysis

RATIONALE & OBJECTIVE

Use of brain natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) for cardiovascular (CV) risk assessment in patients with end-stage kidney disease (ESKD) remains unclear. We examined the associations between different threshold elevations of these peptide levels and clinical outcomes in patients with ESKD.

STUDY DESIGN

Systematic review and meta-analysis.

SETTING & STUDY POPULATIONS

We searched MEDLINE and EMBASE (through September 2019) for observational studies of adults with ESKD (estimated glomerular filtration rate≤15mL/min/1.73m² or receiving maintenance dialysis).

SELECTION CRITERIA FOR STUDIES

Studies that reported NT-proBNP or BNP levels and future CV events, CV mortality, or all-cause mortality.

DATA EXTRACTION

Cohort characteristics and measures of risk associated with study-specified peptide thresholds.

ANALYTICAL APPROACH

Hazard ratios (HRs) for clinical outcomes associated with different NT-proBNP and BNP ranges were categorized into common thresholds and pooled using random-effects meta-analysis.

RESULTS

We identified 61 studies for inclusion in our review (19,688 people). 49 provided sufficient detail for inclusion in meta-analysis. Pooled unadjusted HRs for CV mortality were progressively greater for greater thresholds of NT-proBNP, from 1.45 (95% CI, 0.91-2.32) for levels>2,000pg/mL to 5.95 (95% CI, 4.23-8.37) for levels>15,000pg/mL. Risk for all-cause mortality was significantly higher at all NT-proBNP thresholds ranging from> 1,000 to> 20,000pg/mL (HR range, 1.53-4.00). BNP levels>550pg/mL were associated with increased risk for CV mortality (HR, 2.54; 95% CI, 1.49-4.33), while the risks for all-cause mortality were 2.04 (95% CI, 0.82-5.12) at BNP levels>100pg/mL and 2.97 (95% CI, 2.21-3.98) at BNP levels>550pg/mL. Adjusted analyses demonstrated similarly greater risks for CV and all-cause mortality with greater NT-proBNP concentrations.

LIMITATIONS

Incomplete outcome reporting and risk for outcome reporting bias. Estimation of risk for CV events for specific thresholds of both peptides were limited by poor precision.

CONCLUSIONS

ESKD-specific NT-proBNP and BNP level thresholds of elevation are associated with increased risk for CV and all-cause mortality. This information may help guide interpretation of NT-proBNP and BNP levels in patients with ESKD.

The effect of hemodialysis on N-terminal pro-brain natriuretic peptide: A systematic review and meta-analysis

BACKGROUND

N-terminal pro-brain natriuretic peptide (NT-pro BNP) increases in patients with heart failure and renal failure. Hemodialysis is a useful treatment to these patients. The aim of this study was to conduct a systematic and meta-analysis to evaluate the influence of hemodialysis on NT-pro BNP concentration.

METHODS

Relevant studies were identified by searching in PubMed, Medline, Embase, OVID, Web of Science, China Biology Medicine (CBM) and Google Scholar. Standard errors of mean difference along with its 95% CI were calculated to assess the association of hemodialysis and NT-pro BNP concentration. Heterogeneity, subgroup analysis, sensitivity analysis and publication bias were explored.

RESULTS

Individual patient data was obtained from 270 participants in seven articles suffered from chronic renal failure with regular hemodialysis, which was standard normal distribution. A fixed effects model suggested a pooled mean difference of 79.265 (95% CI: -331.172-489.702) without heterogeneity (Q = 0.70 df = 6 p = 0.994 I² = 0.0%). The adults group estimated a MD of 209.958 (95% CI: -3080.76-3500.67; p = 0.900) with no heterogeneity (Q = 0.70 df = 4 p = 0.983 I² = 0.0%). In the four articles whose data were not standard normal distribution, hemodiafiltration protocols were similar; three articles reported increasing and one decreasing in NT-proBNP concentration.

CONCLUSIONS

Finding of this systematic review and meta-analysis demonstrated that NT-pro BNP may not been influenced by hemodialysis, and it could not been used to determine if heart failure is improving in patients with renal failure who are treated with hemodialysis.

Is N-terminal pro-brain natriuretic peptide a reliable marker for body fluid status in children with chronic kidney disease?

INTRODUCTION

Brain natriuretic peptides, released in response to left ventricular stress, have a strong prognostic value in dialysis patients. However, their role in detecting abnormalities of fluid status is under debate; the relationship between volume status and brain natriuretic peptides (BNPs) differs among various studies. The aim of our study was to evaluate the clinical utility of N-terminal proBNP in the assessment of fluid status and cardiovascular risk in this setting.

MATERIAL AND METHODS

The study included 65 children: 10 pre-dialysis, 13 hemodialysis, 12 peritoneal dialysis patients and 30 healthy controls. Volume status was determined by multifrequency bioimpedance and NT-pro-BNP, as well as echocardiography to estimate the left ventricle structure and function.

RESULTS

The median log NT-proBNP values of hemodialysis and peritoneal dialysis patients were 3.66 (2.05-4.90) and 3.57 (2.51-4.13) pg/ml, respectively, and significantly higher compared with the control group (p < 0.001, p < 0.001). On simple correlation, NT-proBNP was correlated with markers of volume overload and cardiac dysfunction. On multivariate regression analysis, only left ventricle mass index (β = 0.402, p = 0.003) and left atrium diameter (β = 0.263, p = 0.018) were independently associated with NT-proBNP (adjusted R 2 of the model: 0.707, p < 0.001).

CONCLUSIONS

Our research suggested that NT-proBNP, which was correlated with LV systolic and diastolic dysfunction and fluid overload as assessed by bioimpedance, can be used to evaluate cardiovascular states in a chronic kidney disease (CKD) population. From the early stages of CKD, periodic monitoring of NT-proBNP levels may be essential for early detection of patients with high risk of cardiovascular events, and for taking preventive intervention as soon as possible.

N-Terminal Prohormone of Brain Natriuretic Peptide but not C-Terminal Pre-Pro Vasopressin (Copeptin) Level is Associated with the Response to Antihypertensive Therapy in Haemodialysis Patients

BACKGROUND/AIMS

Volume overload, frequently clinically asymptomatic is considered as a causative factor limiting the effectiveness of antihypertensive therapy in haemodialysis (HD) patients. Therefore, the aim of this study was to assess plasma levels of N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) and a C-terminal portion of the precursor of vasopressin (CT-proAVP, copeptin), surrogate markers of volume overload in HD patients in relation to the number of antihypertensive drugs used in the hypertension treatment.

METHODS

One hundred and fifty adult HD patients (92 males) were enrolled into this study. Clinical data concerning blood pressure (BP) measurements prior haemodialysis session and pharmacotherapy were collected from all patients. In addition to routine laboratory parameters, plasma levels of NT-proBNP and CT-proAVP were measured, and daily sodium and water consumption were estimated with a portion-size food frequency questionnaire.

RESULTS

Among 145 (96.7%) hypertensive HD patients, 131 were receiving antihypertensive medication. Despite antihypertensive therapy, 31.0% had inadequate BP control. Plasma concentration of NT-proBNP was associated with systolic (R=0.19; p=0.02) but not diastolic BP values and with the number of received antihypertensive drugs (R=0.21; p=0.01). The highest NT-proBNP values were observed in patients receiving 3 or more antihypertensive drugs. In contrast, no significant correlation was found between plasma CT-proAVP concentrations and BP values as well as and the number of antihypertensive drugs. Receiver operator curve analysis showed that NT-proBNP values over 13,184 pg/mL predicted the use of at least 3 antihypertensive drugs in maximal doses in the therapy of hypertension, similar analyses performed for CT-proAVP showed much less specificity.

CONCLUSIONS

1. Increased levels of NT-proBNP seems to be a better biomarker of multidrug antihypertensive therapy requirement than CT-proAVP. 2. Whether estimation of NT-proBNP in these patients will be also better biomarker than copeptin in the prediction of cardiovascular complications related to hypertension needs further investigations.

NT-proBNP, Cardiometabolic Risk Factors, and Nutritional Status in Hemodialysis Patients

Background

We aimed to evaluate the association between NT-proBNP and malnutrition in HD patients while taking into account the four established categories of parameters for diagnosis of protein energy wasting (PEW).

Methods

A cross-sectional study was performed in Afro-Caribbean dialysis patients. One component in each of the 4 categories for the wasting syndrome was retained: serum albumin ≤ 38 g/L, BMI ≤ 23 Kg/m², serum creatinine ≤ 818 µmol/L, and normalized protein catabolic rate (nPCR) ≤ 0.8 g/kg/day. NT-proBNP was assessed using a chemiluminescence immunoassay. Two multivariate logistic regression models were performed to determine the parameters associated with high NT-proBNP concentrations.

Results

In 207 HD patients, 16.9% had PEW (at least three components). LVEF lower than 60% was found in 13.8% of patients. NT-proBNP levels ranged from 125 to 33144 pg/mL. In model 1, high levels of NT-proBNP (≥6243 pg/mL) were independently associated with PEW OR 14.2 (3.25–62.4), male gender 2.80 (1.22–6.57), hsCRP > 5 mg/L 3.90 (1.77–8.57), and dialysis vintage > 3 years 3.84 (1.35–10.8). In model 2, LVEF OR was 0.93 (0.88–0.98). NT-proBNP concentrations were significantly higher when the PEW component number was higher.

Conclusion

In dialysis patients, high NT-proBNP levels must draw attention to cardiac function but also to nutritional status.

Emergency medicine evaluation and management of the end stage renal disease patient

BACKGROUND

End stage renal disease (ESRD) is increasing in the U.S., and these patients demonstrate greater all-cause mortality, cardiovascular events, and hospitalization rates when compared to those with normal renal function. These patients may experience significant complications associated with loss of renal function and dialysis.

OBJECTIVE

This review evaluates complications of ESRD including cardiopulmonary, neurologic, infectious disease, vascular, and access site complications, as well as medication use in this population.

DISCUSSION

ESRD incidence is rapidly increasing, and patients commonly require renal replacement therapy including hemodialysis (HDS) or peritoneal dialysis (PD), each type with specific features. These patients possess greater risk of neurologic complications, cardiopulmonary pathology, infection, and access site complications. Focused history and physical examination are essential. Neurologic issues include uremic encephalopathy, cerebrovascular pathology, and several others. Cardiopulmonary complications include pericarditis, pericardial effusion/tamponade, acute coronary syndrome, sudden cardiac death, electrolyte abnormalities, pulmonary edema, and air embolism. Infections are common, with patients more commonly presenting in atypical fashion. Access site infections and metastatic infections must be treated aggressively. Access site complications include bleeding, aneurysm/pseudoaneurysm, thrombosis/stenosis, and arterial steal syndrome. Specific medication considerations are required for analgesics, sedatives, neuromuscular blocking agents, antimicrobials, and anticoagulants.

CONCLUSIONS

Consideration of renal physiology with complications in ESRD can assist emergency providers in the evaluation and management of these patients. ESRD affects many organ systems, and specific pharmacologic considerations are required.

Predictive abilities of baseline measurements of fluid overload, assessed by bioimpedance spectroscopy and serum N-terminal pro-B-type natriuretic peptide, for mortality in hemodialysis patients

INTRODUCTION

Fluid overload is one of the most important, yet modifiable, risk factors associated with worse outcomes in hemodialysis (HD) patients. However, its precise assessment in clinical practice is still under investigation.

MATERIAL AND METHODS

This is an observational prospective study which included 285 stable patients with end-stage renal disease on standard thrice-weekly HD therapy. Overhydration was assessed by the combination of relative fluid overload (RFO), using bioimpedance spectroscopy, and N-terminal pro-B-type natriuretic peptide (NT-proBNP). The outcome of interest was all-cause mortality.

RESULTS

The median values for NT-proBNP and RFO were 4595 pg/ml and 6.9%, respectively. We divided the study population into four groups according to these median levels: group 1 - low NT-proBNP and low RFO; group 2 - high NT-proBNP and low RFO; group 3 - low NT-proBNP and high RFO; group 4 - high NT-proBNP and high RFO. During the follow-up (mean: 41.1, median: 48.7 months), 89 (31.2%) patients died. In the univariable Cox survival analysis only patients in group 4, and not those from group 2 or 3, had significantly higher HRs as compared to those in group 1 (HR = 1.5, 95% CI: 0.8-2.8, HR = 1.6, 95% CI: 0.8-2.9 and HR = 2.4, 95% CI: 1.3-4.2, for group 2, 3 and 4, respectively). Furthermore, these results were maintained in the multivariable Cox analysis.

CONCLUSIONS

Including both bioimpedance and NT-proBNP monitoring in a more comprehensive fluid status assessment could improve the diagnosis of fluid overload with a final improvement in patients' outcome.

Indication for Dialysis Initiation and Mortality in Patients With Chronic Kidney Failure: A Retrospective Cohort Study

BACKGROUND

Initiation of maintenance dialysis therapy for patients with chronic kidney failure is a period of high risk for adverse patient outcomes. Whether indications for dialysis therapy initiation are associated with mortality in this population is unknown.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

461 patients who initiated dialysis therapy (hemodialysis, 437; peritoneal dialysis, 24) from January 1, 2004, through December 31, 2012, and were treated in facilities operated by a single dialysis organization. Follow-up for the primary outcome was through December 31, 2013.

PREDICTOR

Clinically documented primary indication for dialysis therapy initiation, as categorized into 4 groups: laboratory evidence of kidney function decline (reference category), uremic symptoms, volume overload or hypertension, and other/unknown.

OUTCOMES

All-cause mortality.

RESULTS

During a median follow-up of 2.4 years, 183 (40%) patients died. Crude mortality rates were 10.0 (95% CI, 6.8-14.7), 12.7 (95% CI, 10.2-15.7), 21.7 (95% CI, 16.4-28.6), and 12.2 (95% CI, 6.8-14.7) deaths/100 patient-years among patients initiating dialysis therapy primarily for laboratory evidence of kidney function decline, uremic symptoms, volume overload or hypertension, and other/unknown reason, respectively. Following adjustment for demographic variables, coexisting illnesses, and estimated glomerular filtration rate, initiation of dialysis therapy for uremic symptoms, volume overload or hypertension, or other/unknown reasons was associated with 1.12 (95% CI, 0.72-1.77), 1.69 (95% CI, 1.02-2.80), and 1.28 (95% CI, 0.73-2.26) times higher risk, respectively, for subsequent mortality compared to initiation for laboratory evidence of kidney function decline.

LIMITATIONS

Possibility of residual confounding by unmeasured variables; reliance on clinical documentation to ascertain exposure.

CONCLUSIONS

Patients initiating dialysis therapy due to volume overload may have increased risk for mortality compared with patients initiating dialysis due to laboratory evidence of kidney function decline. Further studies are needed to identify and test interventions that might reduce this risk.

Management of Chronic Kidney Disease Patients in the Intensive Care Unit: Mixing Acute and Chronic Illness

Patients with chronic kidney disease (CKD) are at high risk for developing critical illness and for admission to intensive care units (ICU). 'Critically ill CKD patients' frequently develop an acute worsening of renal function (i.e. acute-on-chronic, AoC) that contributes to long-term kidney dysfunction, potentially leading to end-stage kidney disease (ESKD). An integrated multidisciplinary effort is thus necessary to adequately manage the multi-organ damage of those kidney patients and contemporaneously reduce the progression of kidney dysfunction when they are critically ill. The aim of this review is to describe (1) the pathophysiological mechanisms underlying the development of AoC kidney dysfunction and its role in the progression toward ESKD; (2) the most common clinical presentations of critical illness among CKD/ESKD patients; and (3) the continuum of care for CKD/ESKD patients from maintenance hemodialysis/peritoneal dialysis to acute renal replacement therapy performed in ICU and, vice-versa, for AoC patients who develop ESKD.

Cardiac biomarkers in dialysis

Cardiovascular disease is the major cause of death, accounting for approximately 40 percent of all-cause mortality in patients receiving either hemodialysis or peritoneal dialysis. Cardiovascular risk stratification is an important aspect of managing dialysis patients as it enables early identification of high-risk patients, so therapeutic interventions can be optimized to lower cardiovascular morbidity and mortality. Biomarkers can detect early stages of cardiac injury so timely intervention can be provided. The B-type natriuretic peptides (Brain Natriuretic peptide [BNP] and N-terminal pro-B-type natriuretic peptide [NT-proBNP]) and troponins have been shown to predict mortality in dialysis patients. Suppression of tumorigenicity 2 (ST2) and galectin-3 are new emerging biomarkers in the field of heart failure in both the general and dialysis populations. This article aims to discuss the current evidence regarding cardiac biomarker use to diagnose myocardial injury and monitor the risk of major adverse cardiovascular events in patients undergoing dialysis.

Inverse relationship of bone mineral density and serum level of N-terminal pro-B-type natriuretic peptide in peritoneal dialysis patients

Objective:

Chronic kidney disease is associated with decreased bone mineral density (BMD). In this study, the relationship between BMD and the fasting serum concentration of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) was evaluated in peritoneal dialysis (PD) patients.

Material and Methods:

Fasting blood samples were obtained from 52 PD patients. BMD was measured by dual energy X-ray absorptiometry of the lumbar vertebrae (L2–L4). The serum NT-pro-BNP level was measured by an electrochemiluminescence immunoassay.

Results:

Ten patients (19.2%) had osteoporosis, 23 patients (44.2%) had osteopenia, and 19 patients had normal BMD. Increased serum NT-pro-BNP (p < 0.001), advanced age (p = 0.012), decreased body mass index (p = 0.006), body height (p = 0.018), and body weight (p = 0.004) were associated with lower lumbar T-scores, but sex, menopausal status, PD modality, diabetes mellitus, and hypertension were not. Multivariate forward stepwise linear regression analysis with adjustment for age, body height, body weight, body mass index, and log-NT-pro-BNP indicated that a high serum level of log-NT-pro-BNP (R² change = 0.346; p < 0.001) and low body weight (R² change = 0.208; p < 0.001) were significantly and independently associated with poor lumbar BMD.

Conclusion:

A high serum level of NT-pro-BNP and low body weight were associated with poor BMD in PD patients.

The role of natriuretic peptides in volume assessment and mortality prediction in Haemodialysis patients

Background

Maintaining optimal fluid balance is essential in haemodialysis (HD) patients but clinical evaluation remains problematic. Other technologies such as bioimpedance are emerging as valuable adjuncts. This study was undertaken to explore the potential utility of the natriuretic peptides – atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in the assessment of fluid status and cardiovascular risk in this setting.

Methods

This was a cross-sectional study carried out in an unselected cohort of 170 prevalent HD patients. Volume status was assessed by clinical parameters – the presence or absence of peripheral oedema, raised jugular venous pressure and basal lung crepitations; by extracellular fluid volume (ECFV) status determined by whole body bioimpedance; and by serum levels of BNP and ANP (pre- and post –dialysis). The relationships of ANP and BNP levels to clinical and bioimpedance parameters of volume status was determined. Patients were followed up for 5 years to assess the relationship of natriuretic peptide levels to mortality.

Results

Bioimpedance estimates of ECFV expansion (>105 % of ideal ECFV) was present in 52 % of patients pre-dialysis. A significant proportion (21 %) of pre-dialysis patients had a depleted ECFV (<95 % of ideal ECFV) pre-dialysis. The situation was reversed post-dialysis. A raised JVP >3 cm was the most reliable clinical sign of ECFV expansion inferred from bioimpedance measurements and natriuretic peptide levels. The vast majority of patients with this sign also had lung crepitations or peripheral oedema or both. BNP was a stronger predictor of ECFV expansion than either pre- or post-dialysis ANP. BNP was also a stronger predictor of five-year survival.

Conclusion

Serum levels of BNP have a strong relationship to both volume status and survival in HD patients. We found no clear role for measurement of ANP, though changes in blood levels may be a sensitive indicator of acute changes in volume status. Whether monitoring levels of these peptides has a role in the management of volume status and cardiovascular risk requires further study.

Cardiovascular biomarkers in chronic kidney disease: state of current research and clinical applicability

The high incidence of cardiovascular events in chronic kidney disease (CKD) warrants an accurate evaluation of risk aimed at reducing the burden of disease and its consequences. The use of biomarkers to identify patients at high risk has been in use in the general population for several decades and has received mixed reactions in the medical community. Some practitioners have become staunch supporters and users while others doubt the utility of biomarkers and rarely measure them. In CKD patients numerous markers similar to those used in the general population and others more specific to the uremic population have emerged; however their utility for routine clinical application remains to be fully elucidated. The reproducibility and standardization of the serum assays are serious limitations to the broad implementation of these tests. The lack of focused research and validation in randomized trials rather than ad hoc measurement of multiple serum markers in observational studies is also cause for concern related to the clinical applicability of these markers. We review the current literature on biomarkers that may have a relevant role in field of nephrology.

NT-proBNP and troponin T levels differ after haemodialysis with a low versus high flux membrane

BACKGROUND

Brain natriuretic peptide (BNP), N-terminal-proBNP (NT-proBNP), and high sensitive cardiac troponin T (TnT) are markers that are elevated in chronic kidney disease and correlate with increased risk of mortality. Data are conflicting on the effect of biomarker levels by hemodialysis (HD).Our aim was to clarify to what extent HD with low-flux (LF) versus high-flux (HF) membranes affects the plasma levels of BNP, NT-proBNP, and TnT.

METHODS AND MATERIALS

31 HD patients were included in a crossover design, randomized to start dialysis with a LF-HD or HF-HD dialyzer. Each patient was his/her own control. The dialyses included in the study were the first treatments of two consecutive weeks with each mode of dialysis. Patients normally on hemodiafiltration (HDF) also performed a HDF the third week. Values after HD were corrected for extent of ultrafiltration.

RESULTS

During LF-HD the biomarkers NT-proBNP and TnT increased (15 versus 6%, P ≤ .001) while there was a slight decrease in BNP (P<.05). During HF-HD the NT-proBNP, BNP and TnT levels decreased (P ≤ .01 for all). During HDF all three markers decreased (P<.01 for all). The rise in TnT during LF-HD correlated with dialysis vintage (months on HD, r = .407, P = .026), Kt/V-urea (r = .383, P = .037), HD time in hours/treatment (r = .447, P = .013) and inversely with residual urinary output (r = -.495, P = .005). The baseline levels of BNP and NT-proBNP correlated with blood pressure.

CONCLUSIONS

Cardiac biomarkers increase slightly during LF-HD. A HF-HD eliminates the biomarkers and can mask increases caused by, e.g., myocardial infarction.

Superior predictive value for NTproBNP compared with high sensitivity cTnT in dialysis patients: a pilot prospective observational study

BACKGROUND/AIMS

The clinical utility of the new biomarker, high sensitivity cardiac T troponin (hs-cTnT) is still unclear in dialysis patients. Furthermore, the prognostic value of combining N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and hs-cTnT has not been explored so far. The objective of this pilot study was to determine the utility of hs-cTnT alone versus hs-cTnT in combination with NT-proBNP for predicting death in a stable hemodialysis cohort.

METHODS

A prospective observational pilot study including 98 chronic asymptomatic hemodialysis patients with a follow up period of 24 months was designed. The cut-off values for NT-proBNP and hs-cTnT were calculated using receiver operating characteristic (ROC) analysis, using mortality as an end-point. Based on the cut-off values, the cohort was divided into four groups. Group 1--NT-proBNP < 14275 pg/ml and hs-cTnT < 69.48 ng/l; group 2--NT-proBNP < 14275 pg/ml and hs-cTnT > 69.48 ng/l; group 3--NT-proBNP > 14275 pg/ml and hs-cTnT < 69.48 ng/l; group 4--NT-proBNP > 14275 pg/ml and hs-cTnT > 69.48 ng/l. Survival for each group was determined using the Kaplan-Meier method and Cox regression analysis.

RESULTS

During the follow-up period 16 patients died. According to the ROC curves analysis, the cut-off point for hs-cTnT and for NT-proBNP were 69.43 ng/l (AUC = 0.618; p = 0.04) and 14275 pg/ml (AUC = 0.722; p = 0.003), respectively. In univariate Cox analysis, both hs-cTnT (HR = 3.34; p = 0.016) and NT-proBNP (HR = 5.94; p = 0.01) were predictors of death. In the multivariable Cox proportional hazards model, only NT-pro-BNP levels above the cut-off value remained an independent predictor of all-cause mortality. The combined elevation of both biomarkers did not improve significantly the prognostic value compared with NT-proBNP alone (HR = 6.15 versus HR =4 .78; p = 0.338).

CONCLUSION

NT-pro-BNP is a strong predictor of overall mortality in asymptomatic hemodialysis patients. The addition of hs-cTnT did not improve the prognostic accuracy compared with NT proBNP alone.

A comparison of markers of myocardial injury and their relation to nutritional parameters in hemodialysis patients

BACKGROUND

Serum cardiac troponin T (cTnT) is a valuable marker of ischemic heart disease (IHD) and left ventricular hypertrophy, as well as a mortality predictor in hemodialysis populations. We compared the value of cTnT, creatinine kinase (CK)-MB mass and myoglobin as mortality predictors in our hemodialysis patients and evaluated their relation to nutritional status.

METHODS

A total of 118 hemodialysis patients were prospectively studied from January 2004 to April 2013. Clinical and laboratory evaluations during the 12-month baseline period included the history of IHD, signs of left ventricular hypertrophy (LVH), Kt/V and serum cardiac markers together with the percentage of body fat (%fat), mid-arm circumference (MAC), mid-arm muscle circumference (MAMC), triceps skinfold (TSF) and BMI.

RESULTS

Underweight patients had significantly higher cTnT values (Mann-Whitney, p<0.05). Correlation analysis (Spearman) showed an inverse association between cTnT and TSF (ρ=-0.22, p<0.05), as well as between CK-MB mass and TSF (ρ=-0.26, p<0.01). In men cTnT also correlated inversely with %fat (ρ=-0.27, p<0.05) and BMI (ρ=-0.33, p<0.05). In addition, myoglobin was correlated significantly with MAC, MAMC and albumin. Among cardiac markers cTnT was the only independent variable predicting mortality (Multivariate Cox regression, HR=1.04 CI (1.01-1.07); p<0.01; measurement units 0.01 μg/L).

CONCLUSION

Troponin T and CK-MB mass were significantly elevated in the underweight patient group. Troponin T was the only independent cardiac marker predictor of all cause mortality in our hemodialysis patients.

Fluid overload in hemodialysis patients: a cross-sectional study to determine its association with cardiac biomarkers and nutritional status

Background

Chronic fluid overload is associated with higher mortality in dialysis patients; however, the link with cardiovascular morbidity has not formally been established and may be influenced by subclinical inflammation. We hypothesized that a relationship exists between fluid overload and [i] cardiovascular laboratory parameter as well as between fluid overload and [ii] inflammatory laboratory parameters. In addition, we aimed to confirm whether volume status correlates with nutritional status.

Methods

We recorded baseline characteristics of 244 hemodialysis patients at three hemodialysis facilities in Vienna (Austria) and determined associations with volume measurements using the body composition monitor (Fresenius/Germany). In one facility comprising 126 patients, we further analyzed cardiovascular, inflammatory and nutritional parameters.

Results

We detected predialysis fluid overload (FO) in 39% of all patients (n = 95) with FO defined as ≥15% of extracellular water (ECW). In this subgroup, the absolute FO was 4.4 +/-1.5 L or 22.9 ± 4.8% of ECW. A sub-analysis of patients from one center showed that FO was negatively associated with body mass index (r = -0.371; p = <0.001), while serum albumin was significantly lower in fluid overloaded patients (p = 0.001). FO was positively associated with D-Dimer (r = 0.316; p = 0.001), troponin T (r = 0.325; p < 0.001), and N-terminal pro-B-type natriuretic peptide (r = 0.436; p < 0.001), but not with investigated inflammatory parameters.

Conclusions

Fluid overload in HD patients was found to be lower in patients with high body mass index, indicating that dry weight was inadequately prescribed and/or difficult to achieve in overweight patients. The association with parameters of cardiovascular compromise and/or damage suggests that fluid overload is a biomarker for cardiovascular risk. Future studies should determine if this applies to patients prior to end-stage renal disease.

[Fluid overload and arterial hypertension in hemodialysis patients]

The water sodium overload is a factor of morbi-mortality and its treatment is one of the markers of adequacy of the hemodialysis treatment. Its first clinical assessment was improved by tools such as echocardiography and ultrasonography of the inferior vena cava, the per-dialytic curve of plasma volume, measuring BNP or proBNP and by impedancemetry. The combination of the evaluation of these parameters and of the clinical situation allows one to assess the extracellular overload, the state of the blood volume and the potential of plasma refilling. The latter is a key factor of the per-dialytic hemodynamic tolerance. It is itself a determining factor in weight can be achieved at the end of the session. Getting the "dry" weight can require modifications of the prescriptions of the hemodialysis sessions, a filling by albumin even a drugs support. Finally, the overload treatment is the central part of the treatment of arterial hypertension, which has to benefit however often from antihypertensive treatment the profit of which is demonstrated.

Novel Biomarkers for Cardio-renal Syndrome

Cardio-renal syndrome (CRS) is a frequent and life-threatening syndrome. It is a disorder of the heart and kidneys in which acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ. Acute kidney injury (AKI) is strongly associated with increased morbidity and mortality in patients with CRS. Early detection of renal dysfunction is not possible using the traditional marker, serum creatinine, and therefore efforts to explore possible biomarkers for early detection of AKI are being made. Apart from predicting AKI, several biomarker studies also identified predictors for poor prognosis such as the need for renal replacement therapy (RRT) or death. It is possible that biomarkers can become risk factors in an improvement of clinical outcomes of CRS. Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with renal dysfunction and the treatment for this disease can be modified based on cardiac biomarkers. In addition to natriuretic peptides, which are established cardiac markers, several new biomarkers have been identified and may play important roles in CRS. In this review, we will briefly summarize the literature on novel renal and cardiac biomarkers and discuss their potential roles in the clinical outcome of CRS.

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.

Optimal fluid control can normalize cardiovascular risk markers and limit left ventricular hypertrophy in thrice weekly dialysis patients

Increased hemodialysis frequency can make fluid overload easier to treat, although most patients are still treated thrice weekly. Chronic fluid overload is associated with left ventricular hypertrophy and elevated serum cardiac biomarkers, recognized as mortality risk factors. Serum cardiac troponin T (cTnT), N-terminal prohormone brain natriuretic peptide (NT-proBNP), left ventricular mass index by cardiac magnetic imaging, and ambulatory blood pressure was measured in 30 thrice weekly hemodiafiltration patients. Time-averaged fluid overload (TAFO) was quantified by bioimpedance spectroscopy. In the study group, left ventricular hypertrophy was found to be 26% by cardiac magnetic resonance. Ambulatory blood pressure was 130 mmHg (112-151) requiring a low equivalent dose of medication of 0.25 units (0-1). Significantly, lower levels of left ventricular mass index (P < 0.05) were associated in those patients with TAFO <1 L or NT-proBNP <1200 pg/mL or cTnT <0.1 ug/L. In the subgroups, 16 patients had normal cTnT (<0.03 ug/L), 16 patients had NT-proBNP <400 pg/mL, and 20 patients had TAFO <1 L. Nine patients had both cTnT <0.03 ug/L and NT-proBNP <400 pg/mL. Normally hydrated thrice-weekly hemodiafiltration patients can have cardiac biomarker and TAFO levels indistinguishable from the normal healthy population. Obtaining TAFO by bioimpedance monitoring can offer a practical alternative to serum cardiac biomarkers.

Troponin I levels and postoperative myocardial infarction following renal transplantation

BACKGROUND

The relationship of routine postoperative troponin I (TnI) monitoring in kidney transplant recipients and in-hospital myocardial infarction (MI) is not known.

METHODS

This observational study evaluated the prevalence of abnormal postoperative TnI (Ortho Clinical Diagnostics assay) in 376 consecutive kidney or kidney/pancreas transplant recipients. In-hospital MI was adjudicated using the universal definition. Rates of death and coronary revascularizations at 1 year were studied. Logistic regression analysis was performed to identify independent predictors of abnormal TnI.

RESULTS

Ninety-five (25%) recipients had abnormal TnI (>0.04 ng/ml) following transplantation. Abnormal TnI levels were more common in older (mean age: 52.2 ± 13.4 vs. 48.3 ± 13.2 years, p = 0.01), diabetic (57.9 vs. 45.6%, p = 0.04), and prior coronary artery disease (31.6 vs. 20.3%, p = 0.02) patients. In-hospital MI occurred in 6 patients (1.6%). All subsequent in-hospital cardiovascular events occurred in the abnormal postoperative TnI group; most in those with TnI levels >1 ng/ml. Previous coronary artery disease was the only independent predictor of a postoperative TnI level >1 ng/ml in multivariate analysis (odds ratio 4.61, 95% confidence interval 1.49-14.32). At 1 year there was no significant difference in death (3.2 vs. 1.8%, p = 0.42) and borderline significant difference in coronary revascularization (5.3 vs. 1.4%, p = 0.049) in abnormal versus normal TnI groups.

CONCLUSIONS

In-hospital MI was infrequent, but abnormal TnI highly prevalent following renal transplantation. Normal TnI levels following renal transplantation had a high negative predictive value in excluding patients likely to develop subsequent postoperative MI. The role of a higher TnI cut-off for screening for postoperative MI in high-risk subgroups deserves future prospective evaluation.

Management of the dialysis patient in general intensive care

The incidence of end-stage renal disease (ESRD) is rising and represents an important group of patients admitted to intensive care units (ICU). ESRD patients have significant co-morbidities and specific medical requirements. Renal replacement therapy (RRT), cardiovascular disease, disorders of electrolytes, drug metabolism, and sepsis are discussed. This review provides a practical approach to problems specific to the ESRD patient and common problems on ICU that require special consideration in ESRD patients. ESRD patients are at risk of hyperkalaemia. I.V. insulin and nebulized salbutamol lower serum potassium until definitive treatment with RRT is instituted. ESRD patients are prone to hypocalcaemia, which requires i.v. replacement if associated with complications. Midazolam has delayed metabolism and elimination in renal impairment and should be avoided. Morphine and its derivatives accumulate in renal failure and shorter-acting opiates are preferable. The use of diuretics is limited to patients with residual urine output. When required, therapeutic systemic anticoagulation should be achieved with unfractionated heparin as it is reversible and its metabolism and clearance are independent of renal function. The risk of sepsis is higher among ESRD patients when compared with patients with normal renal function. Empiric treatment should include both Gram-positive and Gram-negative cover, and methicillin-resistant Staphylococcus aureus cover if the patient has a dialysis catheter. Cardiovascular events account for the majority of deaths among ESRD patients. Troponin-I and CK-MB in combination should be used as markers of acute myocardial damage in the appropriate context, whereas B-type natriuretic peptide and troponin-T values are of less value.

Troponin T Measurements by High-Sensitivity vs Conventional Assays for Risk Stratification in Acute Dyspnea

BACKGROUND

Cardiac troponin T measured by a high-sensitivity assay (hs-cTnT) recently proved to be of prognostic value in several populations. The hs-cTnT assay may also improve risk stratification in acute dyspnea.

METHODS

We prospectively studied the prognostic value of hs-cTnT in 678 consecutive patients presenting to the emergency department with acute dyspnea. On the basis of conventional cardiac troponin T assay (cTnT) and hs-cTnT assay measurements, patients were divided into 3 categories: (1) neither assay increased (cTnT &lt;0.03 μg/L, hs-cTnT &lt;0.016 μg/L), (2) only hs-cTnT increased ≥0.016 μg/L (cTnT &lt;0.03 μg/L), and (3) both assays increased (cTnT ≥0.03 μg/L, hs-cTnT ≥0.016 μg/L). Moreover, the prognostic value of hs-cTnT was investigated if cTnT was not detectable (&lt;0.01).

RESULTS

One hundred seventy-two patients were in the lowest, 282 patients in the middle, and 223 patients in the highest troponin category. Patients in the second and third categories had significantly higher mortality compared to those in the first category (90-day mortality rate 2%, 10%, and 26% in groups 1, 2, and 3, respectively, P &lt; 0.001; 1-year mortality rate 9%, 21%, and 39%, P &lt; 0.001). Importantly, in patients with undetectable cTnT (n = 347, 51%), increased hs-cTnT indicated worse outcome [90-day mortality, odds ratio 4.26 (95% CI 1.19–15.21); 1-year mortality, hazard ratio 2.27 (1.19–4.36), P = 0.013], whereas N-terminal pro–brain-type natriuretic peptide (NT-proBNP) was not predictive of short-term outcome.

CONCLUSIONS

hs-cTnT is associated with mortality in patients presenting with acute dyspnea. hs-cTnT concentrations provide additional prognostic information to cTnT and NT-proBNP testing in patients with cTnT concentrations below the detection limit. In particular, the hs-cTnT cutoff of 0.016 μg/L enables identification of low-risk patients.