Comparison of plasma cardiac troponins T and I in chronically hemodialyzed patients in relation to cardiac status and age

Effect of hemodialysis, coronary artery disease and diabetes on cardiac troponin T: a prospective survey over one year

Background:

Limited data is available about the effects of hemodialysis sessions, coronary artery disease (CAD), and diabetes on serum cardiac troponin T (cTnT) levels in patients with end-stage renal disease (ESRD).

Objectives:

To test whether hemodialysis could be associated with an increase in cTnT concentration. To evaluate if coronary artery disease (CAD) or diabetes are associated with higher cTnT levels in ESRD.

Methods:

Serum cTnT levels were measured immediately before and after dialysis 3 times over 1 year (0, 6, and 12 months).

Results:

A total of 100 ESRD patients without acute coronary syndrome (mean age of 58.5 years, 34% with diabetes, and 37% with CAD) gave 267 pre-dialysis and 260 post-dialysis blood samples. The mean (standard deviation) pre-dialysis cTnT levels were 0.06 (0.12), 0.05 (0.06), and 0.07 (0.07) mcg/L at 0, 6, and 12 months, respectively. The post-dialysis cTnT levels were similar on average. Among 259 samples with cTnT measured both before and after dialysis, 79 (30.5%) showed a decrease in serum cTnT, 97 (37.5%) showed an increase and 83 (32%) showed no change following dialysis. Mean cTnT was higher in CAD than in non-CAD patients. We observed no significant difference in mean cTnT levels between diabetic and non-diabetic patients.

Conclusions:

cTnT levels were not affected by individual hemodialysis sessions, and remained stable around 0.06 mcg/L over a 1-year period in ESRD patients. Random cTnT levels were higher in stable CAD patients undergoing hemodialysis.

Serial increased cardiac troponin T predicts mortality in asymptomatic patients treated with chronic haemodialysis

Background

A single detectable cardiac troponin predicts mortality in patients treated with dialysis. There are limited data on changes in troponin concentration over time and the clinical implications of serial troponin measurement.

Methods

Serial cardiac troponin T (cTnT) was assayed five times over 12 months in a prospective cohort study of patients with end-stage kidney disease treated with haemodialysis. A concentration of cTnT ≥0.04 μg/L was considered increased. Mortality and cardiovascular events were analysed by survival analysis, according to the serial troponin results.

Results

From 100 patients who provided a baseline sample for cTnT, 81 completed five serial measurements. The analysis of patients who completed serial cTnT measurements demonstrated that 28 patients (35%) had normal cTnT concentrations in all five samples, 20 patients (24%) had between one and four increased cTnT measurements and 33 patients (41%) had increased concentrations of cTnT in all five samples. The 1.7-y patient survival was 100%, 90% and 78% for patients with zero, one to four, or five out of five concentrations of cTnT increased, respectively ( P = 0.037), and the corresponding cardiovascular event-free survival was 100%, 91% and 78%, respectively ( P = 0.027).

Conclusions

Serial measurements of cTnT concentration were frequently increased in patients receiving haemodialysis. The number of abnormal measurements over time predicted mortality and cardiovascular adverse events.

Cardiac troponin T in acute coronary syndrome with renal insufficiency

Cardiac troponin levels are frequently elevated in patients with chronic renal failure, hence diagnosis of myocardial necrosis is difficult. The prevalence of elevated serum troponin T was determined and its diagnostic value in acute coronary syndrome was assessed in patients with chronic renal insufficiency. A retrospective cross-sectional analysis was performed in 227 patients with chronic renal insufficiency and a diagnosis of unstable angina, non-ST or ST-segment elevation myocardial infarction. All patients had baseline serum troponin T levels measured at previous visits; the baseline troponin T level was raised in 53.3%. Cardiac troponin T levels did not correlate with creatinine levels, and were not affected by dialysis. Mortality after an acute coronary event was high (46.3%). Because of the elevated baseline cardiac troponin T levels, detection of acute coronary syndrome in patients with chronic renal failure requires evaluation of serial cardiac enzyme measurements and serial 12-lead electrocardiograms. Early and definitive cardiac interventions may contribute towards decreasing the mortality rate in this group of patients.

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.

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.

[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.

Comparison of cardiac troponin T and I in healthy men and in aortic valve replacement

Troponins are of outstanding importance for the diagnosis of myocardial infarction. Cardiac troponin T (cTnT) and the various cardiac troponin I (cTnI) assays differ with respect to method comparison, diagnostic sensitivity and diagnostic specificity. To understand the differences in the diagnostic behavior of troponin assays, AccuTnI and Elecsys Troponin STAT were used in a group of healthy men and in the follow-up of patients with aortic valve replacement (AVR). Within the healthy subjects AccuTnI was able to differentiate two subgroups from each other, whereas the cTnT concentrations of all subjects were below the detection limit. In AVR patients, cTnT and cTnI correlated sufficiently, if the postoperative periods were taken into consideration. There was a rapid increase in cTnI within 24 h. In contrast, a broad peak was evident for cTnT between 48 and 120 h. The results emphasize more the differences in the release of cTnI and cTnT from the cytoplasm and the thin filaments of the cardiomyocytes than the modifications of the troponins circulating in the blood.