Risk stratification using serum concentrations of cardiac troponin T in patients with end-stage renal disease on chronic maintenance dialysis

The occurrence and potential predictive factors of major adverse cardiac and cerebral events in end-stage renal disease patients on continuous ambulatory peritoneal dialysis: A prospective cohort study

Major adverse cardiac and cerebral events (MACCE) are common complications, which prolong hospitalization and increase mortality rate in end-stage renal disease (ESRD) patients who underwent continuous ambulatory peritoneal dialysis (CAPD). Therefore, this study aimed to investigate MACCE occurrence and its potential predictive factors in those patients.In this prospective cohort study, 196 diagnosis of ESRD patients who underwent CAPD treatment in our hospital were eligible, and their clinical data (including demographic data and biochemical indexes) were documented. Besides, their MACCE occurrence was assessed within 3-year follow-up period.In patients, 1-, 2-, and 3-year MACCE occurrence rates were 5.1%, 11.7%, and 14.8%, respectively. Meanwhile, the mean duration of accumulating MACCE occurrence was 33.1 (95% confidence interval: 32.0-34.2) months. Furthermore, age, peritoneal dialysis duration (PDD), C-reactive protein (CRP), fasting blood glucose (FBG) and total cholesterol high correlated with increased accumulating MACCE occurrence, while high-density lipoprotein cholesterol (HDL-C) high correlated with decreased accumulating MACCE occurrence. Notably, by further multivariate Cox's proportional hazard regression analysis, age, PDD, CRP, serum uric acid, and FBG high were independent predictive factors for raised accumulating MACCE occurrence, while HDL-C high was an independent predictive factor for attenuated accumulating MACCE occurrence.MACCE are common; besides, age, peritoneal dialysis duration, C-reactive protein, serum uric acid, fasting blood glucose, and high-density lipoprotein cholesterol serve as potential markers for indicating MACCE in ESRD patients who underwent CAPD.

Soluble ST2 does not change cardiovascular risk prediction compared to cardiac troponin T in kidney transplant candidates

BACKGROUND

Solubility of Tumorigenicity 2 (sST2) is a novel biomarker that better stratifies risk of cardiovascular events (CVE) compared to cardiac troponin T(cTnT) in heart failure. We assessed the association of sST2 with the composite outcome of CVE and/or mortality compared to cTnT in kidney transplant candidates.

METHODS

200 kidney transplant candidates between 2010 and 2013 were included. Elevated sST2 was defined as ≥30ng/ml, cTnT≥0.01 ng/ml.

RESULTS

Median age 53 (interquartile range (IQR) 42-61) years, 59.7% male and 82.0% white. 33.5% had history of CVE, 42.5% left ventricular hypertrophy (LVH) and 15.6% positive cardiac stress test. Elevated sST2 correlated with male gender, history of prior-transplants, CVE, positive stress test, LVH, elevated cTnT, anemia, hyperphosphatemia, increased CRP and non-transplanted status. Male gender, history of CVE and LVH were independent determinants of sST2. During 28 months (IQR 25.3-30), 7.5% died, 13.0% developed CVE and 19.0% developed the composite outcome. Elevated sST2 was associated with the composite outcome (hazard ratio = 1.76, CI 1.06-2.73, p = 0.029) on univariate analysis but not after adjusting for age, diabetes and cTnT (p = 0.068). sST2 did not change the risk prediction model for composite outcome after including age, diabetes, prior history of CVE and elevated cTnT.

CONCLUSIONS

Increased sST2 level is significantly associated with variables associated with CVE in kidney transplant candidates. sST2 was associated with increased risk of the composite outcome of CVE and/or death but not independent of cTnT. Larger studies are needed to confirm these findings and determine whether sST2 has added value in CV risk stratification in this cohort of patients.

Cardiac troponin and C-reactive protein for predicting all-cause and cardiovascular mortality in patients with chronic kidney disease: a meta-analysis

Elevated serum levels of cardiac troponin and C-reactive protein are associated with all-cause and cardiovascular mortality in patients with end-stage renal disease. However, the relationship between these two biomarker levels and mortality in patients with chronic kidney disease remains unclear. We conducted a meta-analysis to quantify the association of cardiac troponin and C-reactive protein levels with all-cause and cardiovascular mortality in patients with chronic kidney disease. Relevant studies were identified by searching the MEDLINE database through November 2013. Studies were included in the meta-analysis if they reported the long-term all-cause or cardiovascular mortality of chronic kidney disease patients with abnormally elevated serum levels of cardiac troponin or C-reactive protein. Summary estimates of association were obtained using a random-effects model. Thirty-two studies met our inclusion criteria. From the pooled analysis, cardiac troponin and C-reactive protein were significantly associated with all-cause (HR 2.93, 95% CI 1.97-4.33 and HR 1.21, 95% CI 1.14-1.29, respectively) and cardiovascular (HR 3.27, 95% CI 1.67-6.41 and HR 1.19, 95% CI 1.10-1.28, respectively) mortality. In the subgroup analysis of cardiac troponin and C-reactive protein, significant heterogeneities were found among the subgroups of population for renal replacement therapy and for the proportion of smokers and the C-reactive protein analysis method. Elevated serum levels of cardiac troponin and C-reactive protein are significant associated with higher risks of all-cause and cardiovascular mortality in patients with chronic kidney disease. Further studies are warranted to explore the risk stratification in chronic kidney disease patients.

Hemodialysis-associated cardiomyopathy: a newly defined disease entity

Cardiovascular disease is the most common cause of the greatly elevated rates of mortality characteristic of patients undergoing maintenance hemodialysis. This article is an attempt to describe the complex and evolving features of cardiac disease routinely encountered in HD patients. Furthermore, by trying to appreciate the pathophysiological drivers, and the crucial interaction with the HD treatment itself, this article seeks to define cardiac disease in this setting (HD-associated cardiomyopathy) as a unique and complex entity. By understanding the phenotype and basis of HD-associated cardiomyopathy, we can develop an evolved understanding of the dominant processes involved in its development and offer up dialysis-based interventions specifically designed to mitigate the cumulative ischemic insults consequent to conventional HD treatment. This article explores the justification of this approach and recent evidence of its efficacy.

B-type natriuretic peptide and prognosis of end-stage renal disease: a meta-analysis

Background

The prognostic importance of B-type natriuretic peptide (BNP) or N-terminal pro BNP (NT-proBNP) in patients with end-stage renal disease (ESRD) remains controversial.

Methodology/Principal Findings

We conducted an unrestricted search from the MEDLINE and EMBASE in all languages that were published between 1966 and Augest2013. Twenty-seven long-term prospective studies met our inclusion criterias. From the pooled analysis, elevated BNP/NT-proBNP was significantly associated with increased all cause mortality [odds ratio (OR), 3.85; 95% CI, 3.11 to 4.75], cardiovascular mortality (OR, 4.05; 95% CI, 2.53 to 6.84), and cardiovascular events (OR, 7.02; 95% CI, 2.21 to 22.33). The funnel plot showed no evidence of publication bias. The corresponding pooled positive and negative likelihood ratio for prediction of all cause mortality were 1.86 (95% CI, 1.66 to 2.08) and 0.48 (95% CI, 0.42 to 0.55), respectively.

Conclusions/Significance

BNP/NT-proBNP is a promising prognostic tool to risk-stratify the patients with ESRD. Further investigations are warranted to elucidate the specific pathogenic mechanisms and the impact of other potential prognostic factors.

Elevated troponin I levels but not low grade chronic inflammation is associated with cardiac-specific mortality in stable hemodialysis patients

BACKGROUND

Elevated cardiac troponin I (TnI) levels are associated with all-cause mortality in stable hemodialysis patients. Their relationship to cardiac-specific death has been inconsistent, and the reason for their elevation is not well understood. We hypothesized that elevated TnI levels in chronic stable hemodialysis patients more specifically track with cardiac mortality, and this mechanism is independent of other contributors of cardiac mortality, such as inflammation.

METHODS

We conducted a single-centre, cohort study of prevalent hemodialysis patients at a tertiary care hospital. Plasma TnI levels were measured with routine monthly blood tests in clinically stable patients for two consecutive months. Plasma TnI was measured by immunoassay and a value above the laboratory reference range (0.06 μg/L) was considered elevated. The primary outcome of death was adjudicated separately for this study, and classified as cardiac, non-cardiac, or unknown. Cox proportional hazard models were used to examine the association of TnI with the all-cause and cardiac-specific mortality, adjusting for potential confounders, including C-reactive protein (CRP) as a marker of inflammation.

RESULTS

Of 133 patients followed for a median of 1.7 years, there were 38 deaths (58% non-cardiac, 39% cardiac, 3% unknown). Elevated TnI was associated with adjusted HR for all-cause mortality of 2.57 (95% CI 1.30-5.09) and an adjusted HR for cardiac death of 3.14 (95% CI 1.07-9.2), after accounting for age, time on dialysis, diabetes status, prior coronary artery disease history, and C-reactive protein. Although CRP was also independently associated with all-cause mortality, it did not add prognostic information to TnI for cardiac-specific death.

CONCLUSION

Elevated TnI levels are independently associated with cardiac and all-cause mortality in asymptomatic hemodialysis patients. The mechanism for this risk is likely independent of inflammation, but may reflect chronic subclinical myocardial injury or unmask those with subclinical atherosclerotic heart disease. Whether those with elevated TnI levels may benefit from additional investigations or more aggressive therapies to treat cardiovascular disease remains to be determined.

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.

Troponin T for the detection of dialysis-induced myocardial stunning in hemodialysis patients

BACKGROUND AND OBJECTIVES

Circulating troponin T levels are frequently elevated in patients undergoing long-term dialysis. The pathophysiology underlying these elevations is controversial.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In 70 prevalent hemodialysis (HD) patients, HD-induced myocardial stunning was assessed echocardiographically at baseline and after 12 months. Nineteen patients were not available for the follow-up analysis. The extent to which predialysis troponin T was associated with the occurrence of HD-induced myocardial stunning was assessed as the primary endpoint.

RESULTS

The median troponin T level in this hemodialysis cohort was 0.06 ng/ml (interquartile range, 0.02-0.10). At baseline, 64% of patients experienced myocardial stunning. These patients showed significantly higher troponin T levels than patients without stunning (0.08 ng/ml [0.05-0.12] versus 0.02 ng/ml [0.01-0.05]). Troponin T levels were significantly correlated to measures of myocardial stunning severity (number of affected segments: r=0.42; change in ejection fraction from beginning of dialysis to end of dialysis: r=-0.45). In receiver-operating characteristic analyses, predialytic troponin T achieved an area under the curve of 0.82 for the detection of myocardial stunning. In multivariable analysis, only ultrafiltration volume (odds ratio, 4.38 for every additional liter) and troponin T (odds ratio, 9.33 for every additional 0.1 ng/ml) were independently associated with myocardial stunning. After 12 months, nine patients had newly developed myocardial stunning and showed a significant increase in troponin T over baseline (0.03 ng/ml at baseline versus 0.05 ng/ml at year 1).

CONCLUSIONS

Troponin T levels in HD patients are associated with the presence and severity of HD-induced myocardial stunning.

Increased cardiac troponin T levels are related to inflammatory markers and various indices of renal function in chronic renal disease patients

BACKGROUND/OBJECTIVES

Cardiovascular disease begins early in the course of chronic kidney disease (CKD), and the glomerular filtration rate (GFR) is an independent risk factor for it. There is little information on cardiac troponin concentrations in patients with CKD who have not commenced dialysis. Factors associated with this deleterious process are not completely understood, and we aimed to determine associated laboratory abnormalities of increased cardiac troponin T (cTnT) in patients with CKD.

METHODS

In this study, 104 patients (65 males and 39 females with mean age of 65 ± 15 years) were recruited. A detailed clinical history was recorded and routine biochemical variables and cTnT levels were measured. GFR was estimated (44.62 ± 14.38 mL/min/1.73 m(2)) using the modification of diet in renal disease study formula.

RESULTS

cTnT is correlated with blood urea (r = 0.262, p < 0.05), uric acid (r = 0.399, p < 0.001), blood phosphorus (r = 0.550, p < 0.001), triglyceride (r = 0.329, p = 0.011), C-reactive protein (CRP; r = 0.768, p < 0.001), renal resistive index (RRI; r = 0.412, p = 0.017), and GFR (r = -0.755, p = 0.011). On stepwise multiple regression analysis, increased CRP (≥12 mg/L), uric acid (≥5 mg/L), and RRI (≥0.70) were independent variables for increased cTnT status (r(2) = 0.053, p < 0.05).

CONCLUSION

Increased cTnT not only shows ongoing inflammation but also is a sensitive marker of functioning renal mass. It is strongly correlated with factors influencing the decline in renal function; thus, it can be used as a renal risk parameter.

Troponin I as a prognostic marker of cardiac events in asymptomatic hemodialysis patients using a sensitive troponin I assay

Elevated troponin T is known to be a prognostic marker for long-term cardiac events and mortality in asymptomatic end-stage renal disease patients. There are conflicting data in this regard with respect to troponin I (TnI). We recently showed a high incidence of elevated TnI levels in asymptomatic hemodialysis (HD) patients using a new generation sensitive TnI assay. The aim of this pilot study was to explore the prognostic value of TnI, as measured with this new assay, as a marker for outcomes in HD patients over a 2-year follow-up period. Fifty-one asymptomatic HD patients were enrolled, and pre-dialysis TnI levels were checked once monthly over 3 consecutive months. Patients were considered to be in the TnI positive group if TnI level on any of the three draws was ≥0.035 ng/ml. All patients were followed for a period of 2 years. The primary end points were acute coronary syndrome, coronary revascularization, sudden death, or cardiac arrest. The secondary end point was all-cause mortality. Elevated TnI levels were found in 51% (26/51) of patients in our cohort. One TnI positive patient was subsequently lost to follow up. There were 6 cardiac events over 2 years, all of which were in the troponin positive group (6/25 or 24%). The presence of a positive TnI at baseline was significantly associated with future cardiac events (p=0.022). A prior history of coronary artery disease (CAD) was also significantly related to future cardiac events (p=0.010). No patient with negative TnI at baseline developed a cardiac event, while 45.5% of those with both a positive TnI and a history of CAD had an event. Fourteen deaths occurred over 2 years, 8 in TnI positive and 6 in the negative group. All-cause mortality was not associated with elevated TnI levels at baseline. We found a significant association between positive TnI and subsequent cardiac events in asymptomatic HD patients followed for 2 years. TnI levels, as measured with a sensitive assay, may be useful in assessing cardiac risk in asymptomatic HD patients. This needs further confirmation in a larger cohort.

Cardiovascular Mortality in Hemodialysis Patients: Clinical and Epidemiological Analysis

Cardiovascular diseases are the leading cause of death in hemodialysis (HD) patients. The annual cardiovascular mortality rate in these patients is 9%, with left ventricular (LV) hypertrophy, ischemic heart disease and heart failure being the most prevalent causes of death. The aim of this study was to determine the cardiovascular mortality rate and estimate the influence of risk factors on cardiovascular mortality in HD patients. A total of 115 patients undergoing HD for at least 6 months were investigated. Initially a cross-sectional study was performed, followed by a two-year follow-up study. Beside the standard biochemical parameters, C-reactive protein (CRP), homocysteine, cardiac troponins (cTn) and the echocardiographic parameters of LV morphology and function (LV mass index, LV fractional shortening, LV ejection fraction) were determined. Results were analyzed using Cox regression analysis, Kaplan-Meier and Log-Rank tests. The average one-year cardiovascular mortality rate was 8.51%. Multivariate Cox regression analysis identified increased CRP, cTn T and I, and LV mass index as independent risk factors for cardiovascular mortality. Patients with cTnT > 0.10 ng/mL and CRP > 10 mg/L had significantly higher cardiovascular mortality risk (p < 0.01) than patients with cTnT > 0.10 ng/mL and CRP ≤ 10 mg/L and those with cTnT ≤ 0.10 ng/mL and CRP ≤ 10 mg/L (p < 0.01). HD patients with high cTnT and CRP have a higher cardiovascular mortality risk.

Improving prognosis estimation in patients with heart failure and the cardiorenal syndrome

The coexistence of heart failure and renal dysfunction constitutes the “cardiorenal syndrome” which is increasingly recognized as a marker of poor prognosis. Patients with cardiorenal dysfunction constitute a large and heterogeneous group where individuals can have markedly different outcomes and disease courses. Thus, the determination of prognosis in this high risk group of patients may pose challenges for clinicians and for researchers alike. In this paper, we discuss the cardiorenal syndrome as it pertains to the patient with heart failure and considerations for further refining prognosis and outcomes in patients with heart failure and renal dysfunction. Conventional assessments of left ventricular function, renal clearance, and functional status can be complemented with identification of coexistent comorbidities, medication needs, microalbuminuria, anemia, biomarker levels, and pulmonary pressures to derive additional prognostic data that can aid management and provide future research directions for this challenging patient group.

Cardiac troponins: outcome predictors in hemodialysis patients

Cardiovascular diseases represent the main cause of death in hemodialysis (HD) patients. Cardiac troponins (cTnT and cTnI) are indicators of myocardial damage. The aims of this study were to assess the prevalence of increased serum cTn in the absence of acute coronary syndrome, to determine overall and cardiovascular mortality rates, and to investigate the possible predictive values of cTnT and cTnI on the outcome in HD patients over a 2-year follow-up period. The study included 115 patients (71 men and 44 women) with an average age of 53.30 +/- 12.17 years who had undergone regular HD for 4.51 +/- 4.01 years and had a mean HD adequacy (Kt/Vsp) of 1.17 +/- 0.23. Increased serum cTnT concentration was found in 37.39% of patients and elevated serum cTnI concentration was present in 11.30% of HD patients without symptoms or signs of acute coronary syndrome. The average 2-year mortality rate was 13.74% and the average 2-year cardiovascular mortality rate was 8.51%. Patients with serum cTnT levels greater than 0.10 ng/ml had significantly lower overall and cardiovascular survival rates than patients with serum cTnT levels of less than 0.10 ng/ml. Patients with serum cTnI levels greater than 0.15 ng/ml had significantly lower overall and cardiovascular survival rates than patients with serum cTnI of less than 0.15 ng/ml. In patients on regular HD, cTn levels are significant outcome predictors.

Time course of degradation of cardiac troponin I in patients with acute ST-elevation myocardial infarction: the ASSENT-2 troponin substudy

Although measurement of troponin is widely used for diagnosing acute myocardial infarction (AMI), its diagnostic potential may be increased by a more complete characterization of its molecular appearance and degradation in the blood. The aim of this study was to define the time course of cardiac troponin I (cTnI) degradation in patients with acute ST-elevation myocardial infarction (STEMI). In the ASSENT-2 substudy, 26 males hospitalized with STEMI were randomized to 2 different thrombolytic drugs within 6 hours after onset of symptoms. Blood samples were obtained just before initiation of thrombolysis and at 30 minutes intervals (7 samples per patient). Western blot analysis was performed using anti-cTnI antibodies and compared with serum concentrations of cTnI. All patients exceeded the cTnI cutoff for AMI during the sampling period; at initiation of therapy, 23 had elevated cTnI values. All patients demonstrated 2 bands on immunoblot: intact cTnI and a single degradation product as early as 90 minutes after onset of symptoms. On subsequent samples, 15 of 26 patients showed multiple degradation products with up to 7 degradation bands. The appearance of fragments was correlated with higher levels of cTnI (P<0.001) and time to initiation of treatment (P=0.058). This study defines for the first time the initial time course of cTnI degradation in STEMI. Intact cTnI and a single degradation product were detectable on immunoblot as early as 90 minutes after onset of symptoms with further degradation after 165 minutes. Infarct size and time to initiation of treatment was the major determinant for degradation.

Cardiovascular Biomarkers in CKD: Pathophysiology and Implications for Clinical Management of Cardiac Disease

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with all forms of chronic kidney disease (CKD). The underlying pathological state is caused by a complex interplay of traditional and nontraditional risk factors that results in atherosclerosis, arteriosclerosis, and altered cardiac morphological characteristics. This multifactorial disease introduces new challenges in predicting and treating patients with CVD sufficiently early in the course of CKD to positively alter patient outcome. Asymptomatic individuals with progressive CVD are a group of patients that deserve focused attention because early detection and intervention may provide the best opportunity for improved outcome. However, identifying CVD in asymptomatic patients with CKD or end-stage renal disease remains a significant hurdle in the management of these patients. Recently, a number of cardiovascular biomarkers were identified as predictors of patient outcome in individuals with CVD and, with additional research, may be used to guide the early diagnosis of and therapy for CVD in patients with CKD. This review examines the pathophysiological characteristics and potential clinical role of these novel cardiovascular biomarkers in risk stratification, risk monitoring, and selection of preventive therapies for patients with CKD.

Serum troponin T concentration as a predictor of mortality in hemodialysis and peritoneal dialysis patients

BACKGROUND

Troponin T is a good predictor of all-cause and cardiovascular mortality in cardiac patients. Although it is known that troponin T is an independent risk factor in dialysis patients as well, its prognostic value when measured routinely in clinical practice, particularly in addition to other risk indicators, is unclear.

METHODS

A cohort of 847 patients who started dialysis therapy between 1997 and 2001 and participated in a multicenter follow-up study was examined. Clinical data were determined 3 months after the start of dialysis therapy. Patients were followed up until date of death or censoring in November 2003.

RESULTS

For patients with troponin T values of 0.05 to 0.10 microg/L, hazard ratio for all-cause mortality was 2.2 (95% confidence interval [CI], 1.7 to 2.8) compared with patients with values less than 0.05 microg/L. For patients with values greater than 0.10 microg/L (11%), hazard ratio was 3.3 (95% CI, 2.5 to 4.5). A survival model with clinical and laboratory risk indicators yielded an area under the curve of 0.81, which did not increase when troponin T level was added to the model. The area under the curve for troponin T level alone was 0.67. No important differences were found between patients on hemodialysis or peritoneal dialysis therapy and between patients with high and low residual renal function.

CONCLUSION

Although troponin T level is an independent risk factor for mortality in dialysis patients, it has limited added predictive power as a routine screening test over other clinical risk factors in dialysis patients.

Troponin I testing in dialysis patients presenting to the emergency room: does troponin I predict the 30-day outcome?

BACKGROUND

Troponins are often measured in acutely ill chronic dialysis patients admitted to the emergency room, irrespective of their clinical presentation. The significance of an elevated troponin level in this setting is unclear.

METHODS

We identified all chronic dialysis patients presenting over 1 year to a tertiary care hospital emergency room who also had at least one cardiac troponin I (cTnI) level determination. We evaluated presenting complaints, risk factors for cardiac disease, cTnI levels, and major cardiac events (MCE; occurrence of cardiovascular death, myocardial infarction, de novo heart failure, or coronary revascularization) within 30 days by chart review in 149 patients (79 on hemodialysis, 70 on peritoneal dialysis).

RESULTS

Chest pain was documented in only 29% of the patients. Twenty-two patients (15%) experienced an MCE. The incidence of an MCE was the same in patients with and without chest pain. A cTnI level >0.1 ng/l was a significant predictor of an MCE (odds ratio 15.2, 95% confidence interval CI 5.26, 43.6). The likelihood ratios for MCEs were 0.32 (CI 0.16, 0.63) for a cTnI level <0.1 ng/l, 0.72 (CI 0.09, 5.5) for cTnI concentrations 0.1-0.3 ng/l, 7.8 (CI 4.2, 15) for a cTnI level >0.3, and 11.7 (CI 4.4, 31) for a cTnI concentration >2.0 ng/l.

CONCLUSION

In acutely ill chronic dialysis patients presenting to a hospital emergency room, an elevated cTnI level indicates an increased 30-day cardiac risk, regardless of their clinical presentation.

Prognostic Value of Troponin T and I Among Asymptomatic Patients With End-Stage Renal Disease

Background— The prognostic usefulness of troponin enzymes in end-stage renal disease (ESRD) patients is controversial. To resolve this uncertainty of troponin as a prognostic tool, we conducted a systematic review to quantify the association between elevated troponin I or T and long-term total mortality among ESRD patients not suspected of having acute coronary syndrome.

Methods and Results— We conducted an unrestricted search from the MEDLINE, EMBASE, and DARE bibliographic databases to December 2004 using the terms troponin.mp. or exp troponin and exp kidney, exp renal, exp kidney disease exp renal replacement therapy . We also manually searched review articles and bibliographies to supplement the search. Studies were included if they were prospective observational studies, used cardiac-specific troponin assays, and evaluated long-term risk of death or cardiac events for asymptomatic ESRD patients. Two authors independently abstracted data on study and patient characteristics. Studies findings were stratified according to troponin T or I levels. We used a random-effects model to pool study results and tested for heterogeneity using χ 2 testing and used funnel-plot inspection to evaluate the presence of publication bias. Data from 28 studies (3931 patients) published between 1999 and December 2004 were included in this review. Patients received dialysis for a median duration of 4 years, with a mean follow-up of 23 months. From the pooled analysis, elevated troponin T (>0.1 ng/mL) was significantly associated with increased all-cause mortality (relative risk, 2.64; 95% CI, 2.17 to 3.20). Although the prognostic effect sizes were all consistent with a positive relationship between troponin T and mortality, there was significant heterogeneity in the magnitude of these effect sizes ( P =0.015). The funnel plot showed evidence of publication bias. Elevated troponin T was also strongly associated with increased cardiac death. Studies evaluating troponin I included a wide variety of assays and differing cut points, rendering synthesis of the study findings difficult.

Conclusions— Elevated troponin T (>0.1 ng/mL) identifies a subgroup of ESRD patients who have poor survival and a high risk of cardiac death despite being asymptomatic. These findings suggest that troponin T is a promising risk stratification tool and may help frame therapeutic decisions. The clinical interpretation of elevated troponin I levels, however, remain unclear, largely because of the lack of standardization of assays.

The significance of elevated troponin T in patients with nondialysis-dependent renal insufficiency: a validation with coronary angiography

BACKGROUND

Patients with elevated troponin are at high risk of adverse outcomes, future cardiac events, and are more likely to have hemodynamically significant coronary artery stenoses. Elevated troponin T (cTnT) in patients with poor renal function portends a poor prognosis; however, findings of significant coronary artery disease (CAD) by coronary angiography have not been demonstrated in patients with poor renal function and elevated cTnT.

HYPOTHESIS

The purpose of this study was to correlate the angiographic findings of patients with elevated cTnT with respect to renal function in patients with nondialysis-dependent renal insufficiency.

METHODS

We retrospectively identified 342 patients with elevated cTnT who underwent coronary angiography in the setting of acute coronary syndrome. Patients were divided into poor (< 40 ml/min) and normal (> 40 ml/min) renal function by measuring their glomerular filtration rate. Our primary outcome was CAD stenosis, defined as epicardial stenosis > or = 70%. Secondary outcomes were rates of contrast nephropathy, initiation of hemodialysis, revascularization, length of stay (LOS), and in-hospital mortality.

RESULTS

There was no significant difference in the prevalence of CAD between patients who had positive cTnT with poor renal function versus patients with positive cTnT and normal renal function (87.1 vs. 89.7%, p = 0.54). This finding persisted after stratifying by age. Patients with impaired renal function had a higher mortality, longer LOS, and a higher rate contrast nephropathy requiring hemodialysis.

CONCLUSION

The association between elevated cTnT and significant CAD stenosis does not vary with renal function.

Reference values for cardiac troponins T and I in healthy neonates

OBJECTIVES

Cardiac troponins T (cTnT) and I (cTnI) are the most sensitive biochemical parameters in the detection of myocardial damage. In neonates, in utero exposure to tocolytic therapy results in detectable values of cardiac troponins after delivery. Additionally, some preliminary results suggest that the upper reference limits for healthy newborns are higher than those for adults but definitive reference limits for newborns are not available. Our objective was to determine those limits.

DESIGN AND METHODS

In this study we investigated the distribution of cTnT and cTnI in cord blood of 869 healthy newborns. cTnT was determined with the 3rd generation assay and cTnI with the Dade Behring assay on a Dimension RxL. For data analysis Student's t test and the Mann-Whitney U test were used.

RESULTS

Using the 99th percentile, the upper reference limit in healthy termed newborns was 0.097 microg/l for cTnT and 0.183 microg/l for cTnI. Compared to the adult values, the newborn upper limit was tripled for cTnT and doubled for cTnI. Statistically significant differences were found between males and females for cTnT and between natural childbirth and caesarean section for cTnI.

CONCLUSION

Healthy-termed newborns have a higher upper reference limit for both cTnT and cTnI compared to adults. This circumstance must be taken into account when interpreting slightly "elevated" cTnT and cTnI values in newborns.

Elevated cardiac troponin T in hemodialysis patients receiving more intravenous iron sucrose

Elevated cardiac troponin T (cTnT) has been associated with shorter survival in hemodialysis patients. Moreover, intravenous (IV) iron treatment has been held responsible for oxidative stress and accelerated atherosclerosis in these patients. In the present study, we investigated the relationship between cTnT concentration, IV iron treatment, and parameters of iron status. In addition, parameters of oxidative stress, inflammation, and atherosclerosis were evaluated. Predialysis blood samples of 78 chronic hemodialysis patients were analyzed for cTnT, malondialdehyde, creatine kinase (CK), and CK-isoenzyme MB (CK-MB). In addition, the mean value of predialysis serum samples collected during the last year, were considered for homocysteine, ferritin, iron, iron binding capacity, blood cell counts, blood urea nitrogen, creatinine, albumin, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), calcium, phosphate, iPTH, cholesterol, and triglyceride. The quantity of IV iron sucrose administered during the last two years was counted from the patients' files. Echocardiography, all events related to ischemic heart disease, and urine volume were also recorded. Elevated cTnT levels (> or =0.10 ng/mL) were found in 18 patients (23.1%). The amount of iron administered was 2264+/-1871 mg with a range 0-7000 mg. Patients with elevated cTnT levels received more IV iron than those with normal cTnT (3692+/-1771 vs. 1761+/-1595 mg, p<0.001). The serum ferritin level was higher in patients with elevated cTnT (median levels; 477 vs. 288 ng/mL; P<0.05). Patients with elevated cTnT were longer on dialysis compared to those with normal levels (median times; 35.5 vs. 15 months, P<0.01) and regression analysis identified the amount of administered iron as an independent factor for elevated cTnT (P<0.01). Intravenous iron treatment and high ferritin concentration are related to high cTnT level, which has previously been incriminated as a survival marker in hemodialysis patients.

Cardiac troponins T and I in patients with end-stage renal disease: the relation with left ventricular mass and their prognostic value

BACKGROUND

Cardiac troponins are frequently elevated in patients with end-stage renal disease (ESRD) in the absence of acute myocardial ischemia. The cause and prognostic value of cardiac troponin elevations in such patients are controversial.

HYPOTHESIS

The aims of this study were (1) to define the incidence of cTnT and cTnI elevations in patients with ESRD, (2) to evaluate the relationship between troponin elevations and left ventricular mass index (LVMI), and (3) to evaluate the prognostic value of elevations in cTnT and cTnI prospectively.

METHODS

We included 129 patients with ESRD (71 men, age 44 +/- 16 years) with no clinical evidence of coronary artery disease. All patients underwent cardiac examinations, including medical history, physical examination, electrocardiogram, and transthoracic echocardiography. Left ventricular mass index was calculated and all patients were followed for 2 years.

RESULTS

The cTnT concentration was > 0.03-0.1 ng/ml in 27 (20.9%) and > 0.1 ng/ml in 27 (20.9%) of the 129 patients. The cTnI concentration was > 0.5 ng/ml in 31 (24%) of 129 patients. Multiple logistic regression analysis identified LVMI (p < 0.001), diabetes (p = 0.001), and serum albumin level (p = 0.009) as a significant independent predictor for elevated cTnT. Left ventricular mass index was the only significant independent predictor for elevated cTnI (p = 0.002). There were 25 (19.4%) deaths during follow-up. Multivariable analysis showed that elevation of cTnT and cTnI did not emerge as an independent predictor for death. Serum albumin level (p < 0.001) was the strongest predictor of mortality, followed by age (p = 0.002) and LVMI (p = 0.005).

CONCLUSIONS

Cardiac troponin T and I related significantly to the LVMI. The increased serum concentration of cardiac troponins probably originates from the heart; however, they are not independent predictors for prognosis.

Significance of Acute versus Chronic Troponin T Elevation in Dialysis Patients

INTRODUCTION

Cardiac troponin T (cTnT) is often elevated in hemodialysis (HD) patients without acute coronary syndrome (ACS). The aim was to assess the predictive value for mortality of pre-dialysis cTnT in asymptomatic patients. If patients became symptomatic during follow-up, cTnT was followed to assess its diagnostic value for ACS.

METHODS

Forty-nine asymptomatic HD patients were included: 30 patients with a history of cardiovascular disease (CV+) and 19 without (CV-). In 11 patients cTnT, myoglobin and creatine kinase (CK) were measured before and during HD. During ACS, cTnT was followed until recovery. A cTnT of > or =0.03 mug/l was considered elevated. Follow-up was 2 years.

RESULTS

cTnT was elevated in 82% (40/49). More CV+ patients had an elevated cTnT (28/30) than CV- patients (12/19; p = 0.02). There was no change in cTnT, myoglobin and CK during HD. During ACS, cTnT increased above baseline, and tended to return to baseline after recovery. Mortality was 33% (16/49). Patients with elevated cTnT had a higher mortality rate (16/40) than patients with negative cTnT (0/9; p = 0.02).

CONCLUSIONS

Elevated cTnT levels in asymptomatic HD patients are not caused by acute myocardial injury or by HD itself. They may be related to chronic myocardial damage and decreased clearance, and are of prognostic value. During ACS, however, a cTnT rise above the individual baseline is diagnostic of acute myocardial injury.

[Value of troponins in acute coronary syndrome in patients with renal failure]

Patients with renal insufficiency can have elevations of serum troponin without suspected clinical coronary ischemia. Although cardiovascular disease is the main cause of death in patients with renal failure, the process of elevation of serum troponin is not well known. Troponin T is more frequently elevated than troponin I in these patients which leads to uncertainty in the clinical interpretation of results. There are studies suggesting that troponin elevations are associated with a higher risk and increased mortality. To explain the process leading to troponin increases in this kind of pathology and to confirm its usefulness in the diagnosis, evolution and prognosis it would be necessary to carry out more clinical studies monitoring troponin and studying the stratification of risk.

Review Article. Cardiac troponins and renal disease

Cardiovascular disease is the most common cause of death in patients with renal failure. Patients with renal failure are at greater risk of atypical presentations of myocardial ischaemia. Traditional markers of myocardial damage are often increased in renal failure in the absence of clinically suspect myocardial ischaemia. The cardiac troponins are specific markers of myocardial injury. Large-scale trials, excluding patients with renal disease, have shown the importance of the cardiac troponins in predicting adverse outcome and in guiding both therapy and intervention in acute coronary syndromes. Cardiac Troponin T and cardiac Troponin I are increased in patients with renal failure and this is likely to represent multifactorial pathology including cardiac dysfunction, left ventricular hypertrophy and cardiac microinfarctions. Increases in serum troponin from baseline, in patients with renal disease with acute coronary syndromes, may represent a poor prognosis. Small studies of patients with renal failure have suggested that elevation of the cardiac troponins is associated with an increased risk of cardiac death.

Prognostication of survival using cardiac troponins and N-terminal pro-brain natriuretic peptide in patients with primary systemic amyloidosis undergoing peripheral blood stem cell transplantation

Primary systemic amyloidosis (AL) is a fatal plasma cell disorder. Pilot data suggest survival is better in patients undergoing peripheral blood stem cell transplantation (PBSCT), but the selection process makes the apparent benefit suspect. We have reported that circulating cardiac biomarkers are the best predictors of survival outside of the transplantation setting. We now test whether cardiac troponins (cTnT and cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are prognostic in transplant recipients. In 98 patients with AL undergoing PBSCT, serum cardiac biomarkers were measured (cTnT, 98 patients; cTnI, 65 patients; and NT-proBNP, 63 patients). Elevated levels of cTnT, cTnI, and NT-proBNP were present in 14%, 43%, and 48% of patients, respectively. At 20 months median follow-up, median survival has not been reached for patients with values below the thresholds; in patients with values above the thresholds, median survival is 26.1 months, 66.1 months, and 66.1 months, respectively. Our previously reported risk systems incorporating these markers were also prognostic, notably the cTnT/NT-proBNP staging. Using this system, 49%, 38%, and 13% of patients were in stage I, stage II, and stage III, respectively. Determining levels of circulating biomarkers may be the most powerful tool for staging patients with AL undergoing PBSCT.

[Cardiac troponin I and T: specific biomarkers of cardiomyocyte]

PURPOSE

Cardiac troponin I and troponin T have replaced creatine kinase MB (CK-MB) for the diagnosis of cardiomyocyte necrosis. Cardiac specificity of these new markers leads to a change in our practice.

CURRENT KNOWLEDGE AND KEY POINTS

Following necrosis, intracellular proteins are released into blood. This easy concept overlaps a biological complexity since troponins are released as complexes leading to various cut-off values depending on the assay used, as least for cardiac troponin I. The increase in both specificity and analytical sensitivity of these markers reached to propose a new definition of myocardial infarction. The diagnosis of acute coronary syndrome is a clinical based diagnosis, the use of troponin contributing to their classification. Finally, pathological processes leading to cardiac injury may induce an increase in the cardiac troponin level.

FUTURE PROSPECTS AND PROJECTS

Troponin standardization is a challenge for the near future leading to better follow-up of patients and comparison between cohorts.

Prognostic value of combination of cardiac troponin T and B-type natriuretic peptide after initiation of treatment in patients with chronic heart failure

BACKGROUND

Recent studies have suggested that cardiac troponin T (cTnT) and troponin I may detect ongoing myocardial damage involved in the progression of chronic heart failure (CHF). This study was prospectively designed to examine whether the combination of cTnT, a marker for ongoing myocardial damage, and B-type natriuretic peptide (BNP), a marker for left ventricular overload, would effectively stratify patients with CHF after initiation of treatment.

METHODS

We measured serum cTnT, plasma BNP, and left ventricular ejection fraction (LVEF) on admission for worsening CHF [New York Heart Association (NYHA) functional class III to IV] and 2 months after initiation of treatment to stabilize CHF (n = 100; mean age, 68 years).

RESULTS

Mean (SD) concentrations of cTnT [0.023 (0.066) vs 0.063 (0.20) micro g/L] and BNP [249 (276) vs 753 (598) ng/L], percentage increased cTnT (>0.01 micro g/L; 35% vs 60%), NYHA functional class [2.5 (0.6) vs 3.5 (5)], and LVEF [43 (13)% vs 36 (12)%] were significantly (P <0.01) improved 2 months after treatment compared with admission. During a mean follow-up of 391 days, there were 44 cardiac events, including 12 cardiac deaths and 32 readmissions for worsening CHF. On a stepwise Cox regression analysis, increased cTnT and BNP were independent predictors of cardiac events (P <0.001). cTnT >0.01 micro g/L and/or BNP >160 ng/L 2 months after initiation of treatment were associated with increased cardiac mortality and morbidity rates.

CONCLUSION

The combination of cTnT and BNP measurements after initiation of treatment may be highly effective for risk stratification in patients with CHF.

Diagnostic accuracy and prognostic relevance of the measurement of cardiac natriuretic peptides: a review

BACKGROUND

The pathophysiologic and clinical relevance of cardiac natriuretic hormone (CNH) assays has been investigated in numerous experimental and clinical studies. Authors have sought to evaluate the diagnostic accuracy and prognostic relevance of the measurement of CNHs according to evidence-based laboratory medicine principles.

METHODS

In June 2003, we ran a computerized literature search on National Library of Medicine using keywords "ANP" and "BNP" and found more than 12 300 and 1200 articles, respectively. A more refined search with keywords "ANP or BNP assay" extracted approximately 7000 and 800 articles, respectively. Only studies specifically designed to evaluate the diagnostic accuracy and prognostic relevance of CNH measurements were selected from this huge mass of articles to be discussed in this review.

CONTENT

Several studies suggested that CNH assays may be clinically useful for the screening and classification of patients with heart failure, as a prognostic marker in cardiovascular disease, in the follow-up of patients with heart failure, and because they may reduce the need for further cardiac investigation. However, it is difficult to compare even the best-designed studies because not only did the authors evaluate different populations, they also used different gold standards.

CONCLUSIONS

CNH assays and conventional diagnostic work-ups provide complementary information for evaluation of the presence and severity of cardiac dysfunction and clinical disease. Several aspects of CNH assays are still to be elucidated, and further work is needed to carefully assess their diagnostic accuracy and prognostic value in cardiac disease.

Troponin levels as a guide to treatment of pulmonary embolism

Right ventricular dysfunction in hemodynamically stable patients with acute pulmonary embolism may be a harbinger of adverse outcomes and may potentially result in the early use of thrombolytic therapy. Risk stratification of these patients is an area of recent and intense investigation with a focus on the assessment of right ventricular function after the embolic event. Echocardiography has been used to identify right ventricular dysfunction but is potentially hampered by a number of limitations. With the onset of right ventricular dilation and possible ischemia in acute pulmonary embolism, elevated serum troponins may be an early and reliable marker of right ventricular dysfunction. In acute pulmonary embolism, both right ventricular dysfunction by echocardiogram and elevated troponin levels have been shown to predict an adverse outcome. Therefore, serum troponin levels should help stratify patients with submassive acute pulmonary embolism into a group in which aggressive medical or surgical intervention would be considered.

Cardiac troponins in renal insufficiency: review and clinical implications

Patients with renal insufficiency may have increased serum troponins even in the absence of clinically suspected acute myocardial ischemia. While cardiovascular disease is the most common cause of death in patients with renal failure, we are just beginning to understand the clinical meaning of serum troponin elevations. Serum troponin T is increased more frequently than troponin I in patients with renal failure, leading clinicians to question its specificity for the diagnosis of myocardial infarction. Many large-scale trials demonstrating the utility of serum troponins in predicting adverse events and in guiding therapy and intervention in acute coronary syndromes have excluded patients with renal failure. Despite persistent uncertainty about the mechanism of elevated serum troponins in patients with reduced renal function, data from smaller groups of renal failure patients have suggested that troponin elevations are associated with added risk, including an increase in mortality. It is possible that increases in serum troponin from baseline in patients with renal insufficiency admitted to hospital with acute coronary syndrome may signify myocardial necrosis. Further studies are needed to clarify this hypothesis.