Cardiac troponin T and malondialdehyde modified plasma lipids in haemodialysis patients.

BACKGROUND: In patients with end-stage renal disease (ESRD), treated with haemodialysis, a high overall mortality is observed. A previous study showed that cardiac troponin T (cTnT) is a strong independent predictor of outcome in this population. In this study we investigated possible causes of cTnT increase and its relationship with a marker of oxidative stress. METHODS: In a group of 71 haemodialysis patients (36 male, 35 female, mean age 68.7+/-1.5 years) we determined cTnT and compared its presence with several biochemical parameters and with malondialdehyde (MDA), which is an indicator of oxidative stress. None of the patients suffered an acute coronary event during the observation period. Three measurements of cTnT and MDA were performed with a 2-week interval. Forty-nine patients underwent a transthoracic echocardiography. RESULTS: Twenty-nine patients (or 40.8%) had a positive cTnT determination (defined as cTnT >/=0.10 ng/ml). cTnT positive patients had significantly higher levels of MDA (P=0.0125), C-reactive protein (CRP) (P=0.04) and pre-dialysis urea (P=0.04). Regression analysis showed that both pre-dialysis urea and MDA independently influenced cTnT. No correlation was found with age, dialysis adequacy, post-dialysis urea, total cholesterol, white blood cell count, fibrinogen or any of the echocardiographical parameters. Presence of heart failure, diabetes or use of medication could not discriminate between cTnT positive and cTnT negative patients. MDA levels correlated positively with time on haemodialysis (P=0.0021). Echocardiography showed left ventricular hypertrophy in 88% of the examined patients and impaired wall motion in 35%. Patients with clinical signs of heart failure had a lower ejection fraction and worse wall motion score index. No correlation existed between echocardiographic findings and cTnT or MDA. Survival was independently predicted by cTnT (P=0.0025), MDA (P=0.0007), CRP (P=0.006) and age (P=0.0143). Patients with both cTnT and CRP increase had a survival of <50% at 1 year, compared with 90% in patients with both cTnT and CRP within the normal range and 80% when either CRP or cTnT was increased (chi(2)=12.127; P=0.0023). CONCLUSIONS: This study confirms that the presence of cTnT predicts prognosis in ESRD. The presence of cTnT is linked to oxidative stress, inflammation and uraemia. The absence of specific findings on EKG and echocardiography points towards subclinical myocardial damage caused by endothelial disturbances.     

The predictive value of cardiac troponin T measurements in subjects on regular haemodialysis.

BACKGROUND: Cardiac troponin T (cTnT) is a subunit of the cardiac actin-myosin complex, which leaks into the circulation when myocardial necrosis is present. Detection of cTnT is associated with a poor outcome in patients with unstable angina, and is a useful tool for risk stratification. The value of cTnT determination in patients with renal failure has been questioned, and the specificity of cTnT in this particular group has not been established. METHODS: In the present study, 94 patients at a single centre were followed prospectively after three determinations of cTNT, at 1-month intervals. The outcome after 12 months was chosen as the end-point. cTnT was measured using both a quantitative chemiluminiscence immunoassay and a qualitative rapid bedside immunoassay on a test strip. The maximum of three measurements was used and was correlated with different parameters and outcome. The following statistical tests were performed: Kaplan-Meier analysis, Cox's proportional regression analysis for measuring survival and logistic regression for analysing factors influencing cTnT. RESULTS: Forty seven of the 94 patients had a positive cTnT by test strip defined as >0.10 ng/ml. Twenty four patients died in the follow-up period (14 from cardiovascular causes). Twenty of the 24 non-survivors had an increased cTnT by test strip and 23 had increased cTnT by laboratory immunoassay. The outcome analysed by a Cox's proportional regression analysis showed that the factors which influenced survival significantly were cTnT, the presence of ischaemic heart disease, C-reactive protein (CRP) and prealbumin. A logistic multivariate analysis revealed that age and CRP significantly influenced cTnT. A good correlation was found between cTnT determined by test strip and in the laboratory. CONCLUSION: cTnT is elevated in a large number of patients on regular haemodialysis and is a significant independent predictor of outcome. Increased cTnT is significantly predicted by age and CRP.     

History of acute coronary events during the predialysis phase of chronic kidney disease is a strong risk factor for major adverse cardiac events in patients initiating haemodialysis.

An initial acute coronary event is an important predictor of future cardiovascular events and all-cause mortality in patients with chronic kidney disease. The aim of this study was to identify an association between acute coronary events during the predialysis phase of chronic kidney disease and major adverse cardiac events in patients initiating maintenance haemodialysis. One hundred sixty-nine patients initiating maintenance haemodialysis were enrolled in this study. In the subsequent follow-up period (median: 60 months), subjects experiencing an initial major adverse cardiac event were compared with those who did not have such an event on the basis of several clinical parameter measurements at the end of the predialysis phase. A history of an acute coronary event was present in 21 patients (12%), and these patients had a higher cumulative major adverse cardiac event rate during follow-up than subjects without a history of acute coronary event (75 vs 19%, P < 0.001). Multivariate Cox regression analysis showed that the following four parameters independently predicted major adverse cardiac events: a history of acute coronary events (hazard ratio, 4.19; 95% confidence interval, 1.61 to 8.13; P < 0.001), presence of diabetes (hazard ratio, 7.70; 95% confidence interval, 3.29 to 23.83; P < 0.001), each 1 g/dl increment in haemoglobin (hazard ratio, 1.57; 95% confidence interval, 1.23 to 2.34; P = 0.002) and each 1 kg/m(2) decrement in body mass index (hazard ratio, 0.80; 95% confidence interval, 0.72 to 0.98; P = 0.005). In conclusion, these results suggest that a history of acute coronary events, presence of diabetes, increased haemoglobin concentration or decreased body mass index at the end of the predialysis phase were significantly associated with the occurrence of a major adverse cardiac event in patients initiating maintenance haemodialysis.     

Cardiac high-sensitivity troponin T measurement: A layer of complexity in managing haemodialysis patients

Aim: To determine: (i) the proportion of stable asymptomatic haemodialysis patients with elevated troponin; (ii) stability of troponin values after dialysis and over a 2‐week interval; and (iii) whether high‐sensitivity troponin T (hsTnT) was associated with higher prevalence of cardiovascular risk factors or cardiovascular disease in these patients. Methods: We measured hsTnT and the fourth generation troponin I before and after dialysis in 103 stable in‐centre haemodialysis patients without ischaemic symptoms. Patients were divided into quartiles to test for associations with established cardiovascular risk factors or disease. Results: hsTnT was above the 99th percentile for the general population in 99% of haemodialysis patients compared with only 13% elevation for the troponin I assay (P < 0.001). Median pre‐dialysis hsTnT concentrations were unchanged after a 2‐week interval (69 vs 69 ng/L, P = 0.55) but fell slightly immediately following dialysis (69 vs 61 ng/L, P < 0.001). Established coronary artery disease (59% vs 22%), peripheral vascular disease (38% vs 4%) and diabetes (18% vs 7%) were more prevalent (P < 0.05) in those in the highest quartile for hsTnT compared with those in the lowest quartile. Conclusion: Almost all in‐centre haemodialysis patients have elevated troponin T in their baseline stable state and this appears unchanged over a 2‐week interval. Such a high rate of baseline elevation of hsTnT may lead to confusion in managing acute coronary syndrome in this group of patients, particularly when symptoms are atypical. We recommend that if Troponin I assay is unavailable then baseline hsTnT concentrations are measured periodically in all haemodialysis patients.     

Elevated concentrations of cardiac troponins are associated with severe coronary artery calcification in asymptomatic haemodialysis patients.

BACKGROUND: Elevated concentrations of cardiac biomarkers, such as troponins and natriuretic peptides, have been shown to be predictive of poorer long-term cardiovascular outcomes in stable patients with end-stage renal disease (ESRD). However, little is known about the relationship between elevated concentrations of these cardiac markers and underlying coronary artery pathology in these patients. The aim of the present study was to investigate associations between coronary artery calcification (CAC) and the concentrations of cardiac biomarkers in ESRD patients. METHODS: We conducted a cross-sectional study of 38 asymptomatic patients (median age, 54 years; 26 males, 12 females; diabetic, 39%) who were undergoing chronic haemodialysis. In these patients, pre-dialysis circulating concentrations of cardiac troponin T (cTnT), cardiac troponin I (cTnI), creatine kinase-MB (CK-MB) and B-type natriuretic peptide (BNP) were measured. We quantified the level of CAC by multirow spiral computed tomography to obtain a CAC score. CAC scores > or = 400 were defined as being indicative of severe CAC. RESULTS: Severe CAC was detected in 17 patients (45%). The degree of CAC severity was positively associated (P < 0.05) with cTnT concentrations. Thus, 15% of patients had severe CAC in the lowest tertile of cTnT, 50% had severe CAC in the middle third, and 69% in the highest third. Similarly, the degree of severity of CAC was positively associated (P < 0.01) with cTnI concentrations across concentration categories. In contrast, there was no association between the degree of CAC severity and the concentrations of either BNP or CK-MB. A logistic regression analysis revealed that elevated concentrations of cTnT (> or = median vs or = 0.1 ng/ml vs 相似文献   

Factors associated with increased serum levels of cardiac troponins T and I in chronic haemodialysis patients: Chronic Haemodialysis And New Cardiac Markers Evaluation (CHANCE) study.

BACKGROUND: Serum concentrations of the cardiac troponins (cTn) T and I, specific markers of myocardial injury, are frequently elevated in haemodialysis patients. The clinical relevance of this is unclear. The aim of this study was to investigate factors associated with increased serum levels of cTn in haemodialysis patients. METHODS: We included in this cross-sectional study 258 chronic haemodialysis patients (150 men, age 60+/-15 years) without acute coronary symptoms. Clinical data, echocardiographic hypertrophy, biochemical status, and haemodialysis regimen were evaluated for each patient. Pre-dialysis serum cTnT (Elecsys, Roche), cTnI (Stratus and RXL, Dade-Berhing), and CK-MB (Stratus, Dade-Berhing) concentrations were determined. Logistic regression was the principal method of analysis. RESULTS: Pre-dialysis levels of cTnT >0.1 ng/ml (n=48, 18.6% of patients) were associated with age (P<0.001), diabetes (P<0.005), history of ischaemic heart disease (P<0.05), and left ventricular hypertrophy (P<0.05). In multivariate analysis, age odds ratio ((OR) 1.04), diabetes (OR 4.9), and indexed left ventricular mass (OR 1.01) were found to be independently associated with cTnT concentration above the threshold. Only six patients had cTnI-Stratus levels >0.6 ng/ml. cTnI-RXL levels >0.3 ng/ml (n=13, 5.0%) were associated with age (P=0.05) and hypercholesterolaemia (P<0.05). Only age (OR 1.06) remained associated in multivariate analysis. CONCLUSION: Elevated baseline serum levels of cardiac troponins were associated with cardiovascular risk factors, history of ischaemic heart disease and left ventricular hypertrophy in asymptomatic chronic haemodialysis patients.     

Measurement of circulating troponin Ic enhances the prognostic value of C-reactive protein in haemodialysis patients.

BACKGROUND: Cardiac Troponin I (cTnI) levels are considered an important diagnostic tool in acute coronary events. They could be of predictive value in haemodialysis (HD) patients. However, the relationship between cTnI and the HD-induced inflammatory state remains unclear. The aim of this study was to explore the prognostic relevance to all-cause and cardiovascular mortalities in HD patients of cTnI, in combination with highly sensitive C-reactive protein (hs-CRP) levels. METHODS: We measured cTnI and hs-CRP at baseline (March 10 to November 16, 2001) in 191 HD patients without clinical signs of acute coronary artery disease [median age 66.7 years (range 22.3-93.5), 94 females, 97 males]. We used a cTnI concentration with a total imprecision of 10% (0.03 microg/l), determined in the laboratory, as the analytical threshold value. Patients were followed for mortality until 1 January, 2003 (median follow-up 418 days). The adjusted relative risks (RRs) of death and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models. RESULTS: A significant proportion (25.1%) of patients had elevated CTnl, > or =0.03 microg/l; 40.3% of patients had CRP concentrations > or =10 mg/l. During follow-up, 29 patients died, 44.8% due to cardiac causes. Elevated cTnI or CRP levels were associated with increased mortality [RR adjusted for age, sex and duration of dialysis 4.2 (1.9-9.0) for cTnI > or =0.03 microg/l and 3.6 (1.6-8.1) for CRP > or =10 mg/l], cTnI being particularly predictive of cardiovascular death. Moreover, the combination of elevated hs-CRP (> or =10 mg/l) and circulating cTnI (> or =0.03 microg/l) dramatically impaired the HD survival rate [adjusted RR for all-cause mortality 16.9 (4.5-63.8)]. CONCLUSION: Circulating cTnI was associated with poor prognosis, especially when combined with elevated CRP, strongly supporting the adoption of regular cTnI testing in HD patients.     

Effect of three different anaesthetic agents on the postoperative production of cardiac troponin T in paediatric cardiac surgery

Background. Paediatric cardiac surgery is associated with somedegree of myocardial injury. Ischaemic preconditioning (IP)has been investigated widely in the adult population. Volatileagents have been shown to simulate IP providing extra protectionto the myocardium during adult cardiopulmonary bypass (CPB)while propofol seems to act through different mechanisms. IPhas not been investigated in the paediatric population to thesame extent. Cardiac troponin T (cTnT) is a reliable markerof myocardial injury in neonates and children. We have investigatedthe relationship between three anaesthetic agents, midazolam,propofol, and sevoflurane, and postoperative production of cTnT. Methods. Ninety patients undergoing repair of congenital heartdefect with CPB were investigated in a prospective randomizedstudy. cTnT was measured four times during the first 24 h followingadmission to the paediatric intensive care unit. Other variablesmeasured included arterial blood gases, lactate, fluid balance,use of inotropic drugs,     

Cardiac troponin I (2nd generation assay) in chronic haemodialysis patients: prevalence and prognostic value.

BACKGROUND: Elevated serum cardiac troponin T (cTnT) levels are frequently observed in chronic dialysis patients and have been shown to be associated with increased morbidity and mortality. The aim of this study was to determine whether cardiac troponin I (cTnI), which is less frequently elevated, has similar clinical significance. METHODS: We studied 101 asymptomatic patients with no clinical evidence of coronary artery disease who were undergoing chronic dialytic treatment. We measured their serum cTnI levels immediately before the start of their dialysis sessions by a second-generation assay (OPUS-DADE). Our study included a year-long follow-up with trimestrial cTnI assays as well as clinical, X-ray and echocardiographic surveillance. We considered patients with serum cTnI > or =0.15 ng/ml as positive and those with levels <0.15 ng/ml as negative. RESULTS: Among the 14 patients with high serum cTnI levels, nine (64%) suffered acute cardiac events during the 12-month follow-up. In contrast, among the 72 patients with low cTnI levels only seven (9.7%) had acute events. In another group of 15 patients with variable cTnI levels, three patients (20%) had cardiac events. CONCLUSION: Based on these results, serum cTnI appears to be a valuable predictive marker of cardiovascular events in asymptomatic dialysis patients. For those patients who might benefit from thorough cardiac investigation and treatment, information on cTnI could be useful in preventing cardiac events.     

Serum troponin T measurement in patients with chronic renal impairment predicts survival and vascular disease: a 2 year prospective study.

BACKGROUND: Cardiovascular mortality in end-stage renal failure patients is high and early risk stratification in these patients may aid clinical management improving outcomes. Cardiac troponin T (cTnT) is a component of the cardiac myocyte which is released into the circulation following myocardial necrosis. It has been shown to be of prognostic significance in patients with unstable angina. The role of cTnT in patients with renal disease remains unclear. The aim of this investigation, therefore, was to assess the prognostic significance of cTnT in chronic renal impairment patients, pre-dialysis. METHODS: Ninety-six patients with chronic renal impairment were followed prospectively after cTnT determination by a quantitative laboratory method. The clinical outcomes after 2 years were determined. The measured cTnT values were correlated with biochemical parameters and clinical end-points. RESULTS: A cut-off of 0.1 ng/ml was used in assessing the prognostic significance of cTnT. Twenty-five patients had a cTnT >0.1 ng/ml, whilst 71 had a cTnT 0.1 ng/ml was 42% compared with 14% in those with levels below the cut-off. Thirty-three patients died or had a vascular event. The rate of death or a vascular event in the elevated group was 64% compared with 24% in those with levels below the cut-off. At the end of the study, 23 patients were treated by continuous ambulatory peritoneal dialysis, 29 by haemodialysis, 22 had functioning renal transplants and one patient was not on renal replacement therapy. Factors that were found to significantly affect cTnT were diabetes, age and urea. cTnT was found to be a significant predictor of survival in these patients. Patients with high cTnT values were more likely to end up on haemodialysis. No relation of renal function to cTnT level was found. CONCLUSIONS: These results show that in patients with renal impairment, the measurement of cTnT prior to commencing renal replacement is a significant independent predictor of survival. cTnT did show potential as a prognostic test to stratify patients with a high cardiovascular risk and may enable intensive risk factor modification in this patient group. This may be of further use in selection of patients' suitability for renal transplantation.     

Perioperative ST-segment depression and troponin T release. Identification of patients with highest risk for myocardial damage

BACKGROUND: Patients undergoing major vascular surgery are at constant risk of developing perioperative myocardial complications, especially myocardial infarction. The following study was performed to answer the question whether ST segment changes, analysed by Holter monitoring and ST segment analysis, are accompanied by release of cardiac troponin T, a highly specific marker of myocardial damage. METHODS: Twenty patients undergoing elective aortic resection were studied by performing Holter ECG, including ST segment analysis, beginning on the evening before surgery until the third postoperative day. Within this period serum levels of cardiac troponin T were determined at 8 timepoints. RESULTS: A total of 8/20 of the patients (40%) showed significant ST depressions (range -0.17/-0.68 mV), without any clinical symptom, with a median of 9 episodes (range 2-24). In 3 of the 8 patients, each with repetitive periods of ST depression, elevated troponin T levels were found (0.45/0.52/1.69 micrograms/l). No troponin T release nor cardiac events were noticed in the remaining patients. No dependency could be found between troponin T release and the magnitude of ST depression or the number of ST depression episodes. CONCLUSION: Haemodynamic changes, oxygen imbalance and stress during major vascular surgery frequently lead to an ischaemic burden, which is indicated by ST segment changes during ECG ST analysis. Longlasting ST depression reaching an individual critical cut-off limit followed by structural myocardial damage may be verified by elevated levels of cardiac troponin T. Prolonged periods of ST depression should be followed by determination of cardiac troponin T.     

Elevated cardiac troponin T in peritoneal dialysis patients is associated with CRP and predicts all-cause mortality and cardiac death.

BACKGROUND: Cardiac troponin T (cTnT) is a highly sensitive and specific marker of myocardial damage. In sera from patients with end-stage renal disease, cTnT may be elevated without other signs of acute myocardial injury. It has been shown that elevated cTnT in haemodialysis patients is associated with poor prognostic outcome. The aim of the present study was to test the hypothesis that elevated cTnT in a single serum sample from peritoneal dialysis (PD) patients is of prognostic importance. METHODS: Blood samples were taken from 26 randomly selected PD patients without signs of acute myocardial ischaemia. Sera were analysed for: cTnT with the second generation TnT ELISA on ES 300; cardiac troponin I (cTnI) with Opus Plus; and for creatine kinase-MB (CKMB) mass and C-reactive protein (CRP). After 4 years, clinical outcomes were evaluated by chart review. The influence on survival was tested with Kaplan-Meier analysis and Cox's proportional regression analysis. RESULTS: Concentrations of cTnT >/=0.04 micro g/l and CRP >/=10 mg/l were strong predictors of all-cause mortality in univariate analysis. Twelve out of 14 patients with cTnT >/=0.04 micro g/l died compared with three out of 12 with cTnT <0.04 micro g/l. Other factors that influenced survival were age and the presence of ischaemic heart disease (IHD). There was a significant positive correlation between cTnT and CRP, and between cTnT and age. Cardiac troponin T was an independent predictor compared with age but not compared with CRP and IHD. Neither cTnI nor CKMB mass concentrations were related to survival. CONCLUSION: Elevated serum concentrations of cTnT significantly predicted poor outcome and there was a correlation between cTnT and CRP concentrations in samples from PD patients. Cardiac troponin I and CKMB mass had no prognostic value.     

Diagnostic efficiency of rejection monitoring after heart transplantation with cardiac troponin T is improved in specific patient subgroups

Cardiac troponin T (cTnT) is a cardio-specific myofibrillar protein known to be elevated early after heart transplantation and during cardiac allograft rejection. cTnT determination in heart allograft recipients showed elevated levels in patients with higher degrees of graft rejection (International Society for Heart and Lung Transplantation grades >/=3A-4). Subgroup analyses revealed demographic patient characteristics markedly improving the diagnostic efficiency of cTnT measurement for rejection monitoring, including male recipient gender, recipient age <60 yr, female donor gender and donor age >/= 33 yr. The clinical utility of these parameters was confirmed by longitudinal patient data and may help to select recipients most likely to benefit from cTnT rejection surveillance.     

QTc dispersion in haemodialysis patients with cardiac complications

BACKGROUND AND AIMS: QTc dispersion (Maximum - Minimum QTc interval on a standard 12-lead electrocardiogram (ECG)) is a useful predictor of tachyarrhythmic events and related sudden cardiac death. Recent studies have reported that QTc dispersion is prolonged in patients receiving haemodialysis (HD), and it is often further prolonged following HD treatment. In the present study, we examine whether the patients who are susceptible to prolongation of QTc dispersion by HD are prone to life-threatening cardiovascular events and related deaths. METHODS: Forty-eight patients with cardiac symptoms such as chest pain (n = 32), arrhythmia (n = 2) or heart failure (n = 14) and receiving chronic HD treatment (40 males and eight females) were subjected to the present study. Twenty-six of a total 48 patients were given a diagnosis of ischaemic heart disease (IHD) by coronary angiography. Ten patients had cerebrovascular accidents and 11 patients had peripheral vascular disease. After the ECG recording, a prospective follow up was conducted for 37 +/- 24 months. RESULTS: During the follow-up period, 30 patients had cardiac events, and 23 including 18 cardiovascular deaths occurred as outcomes. Throughout the total period, patients who showed prolongation of QTc dispersion after HD had cardiovascular deaths with higher incidence than those did not show the prolongation. CONCLUSIONS: We consider that prolongation of QTc dispersion after HD treatment can predict the prognosis of patients with renal failure bearing cardiac complications. Great care is necessary for such patients if they show longer QTc dispersion and/or susceptibility for further prolongation after HD treatment.     

Increased cardiac troponin T and endothelin-1 concentrations in dialysis patients may indicate heart disease.

BACKGROUND: Cardiac troponin T (cTnT) is a highly sensitive marker for the detection of myocardial damage. However, patients maintained on chronic dialysis often have increased serum cTnT concentrations without evidence of acute myocardial injury. The reason for this is unclear. In chronic haemodialysis patients, elevated plasma concentrations of big endothelin-1 (big ET-1) and endothelin-1 (ET-1) have been reported which may be associated with ischaemic heart disease. The aim of the present study was to investigate possible associations between cTnT, big ET-1, ET-1, other cardiac markers and cardiac disease in dialysis patients. METHODS: Thirty-six haemodialysis (HD) patients and 26 peritoneal dialysis (PD) patients without symptoms of acute myocardial ischaemia were investigated. In all patients, serum concentrations of cTnT (2nd generation ELISA), cardiac troponin I (TnI) (Opus, Behring), creatine kinase MB (CKMB) mass and creatine kinase (CK) were determined, in HD patients before and after dialysis. Additionally, in HD patients, plasma ET-1 and big ET-1 were measured. In 27 HD patients, left ventricular mass index (LVMI) was determined. Patients with ischaemic heart disease (IHD) were compared with non-IHD patients. RESULTS: Serum cTnT was elevated (> or =0.10 microg/l) in 20 of 36 HD patients and in eight of 26 PD patients. cTnI was elevated (> or =0.5 microg/l) in four of 62 dialysis patients. HD+PD patients with IHD showed higher cTnT than HD+PD patients without IHD, and ET-1 concentrations were higher in HD patients with than without IHD. In HD patients, there was a positive correlation between cTnT and big ET-1. In HD patients with left ventricular hypertrophy (LVH), serum cTnT, CKMB mass and post-dialysis plasma big ET-1 were higher than in patients with normal LVMI. Furthermore there was a positive correlation between cTnT levels and LVMI. CONCLUSION: These findings suggest that circulating cTnT may reflect left ventricular hypertrophy and/or myocardial ischaemia in dialysis patients, and indicate that ET-1 and big ET-1 might be associated with these conditions.     

Cardiac troponin T: A new marker of myocardial tissue damage in bypass surgery

The purpose of this study was to evaluate cardiac troponin T (TnT) in the diagnosis of minor perioperative myocardial tissue damage and small myocardial infarctions during aortocoronary bypass surgery. In 15 patients without enzymatic or electrocardiographic signs of perioperative myocardial ischemia (group 1, uncomplicated bypass surgery), TnT did not exceed 3.55 μg/L. In 3 patients with perioperative non-Q-wave infarctions (group 2), TnT was significantly higher than in group 1 patients. In all 3 patients, TnT peak concentrations exceeded 3.5 μg/L. Thirteen patients (group 3, borderline cases) showed either signs of perioperative myocardial ischemia by creatine kinase isoenzyme MB (CKMB) activity levels (CKMB > 20 U/L on the first postoperative day, 3 patients) or by electrocardiography (new ST-T segment alterations, 10 patients). TnT concentrations were comparable to group 1 patients and indicated uncomplicated bypass surgery in all 3 patients with solely elevated CKMB activities. On the other hand, TnT concentrations in 3 patients with electrocardiographic signs of perioperative myocardial ischemia were significantly higher than in uncomplicated patients (group 1) with peak values exceeding 3.5 μg/L. Thus, TnT indicated perioperative non-Q-wave infarctions not detected by CKMB activity in these 3 patients. These results are in accordance with findings in nonsurgical patients. They suggest a higher sensitivity and specificity of cardiac TnT compared to CKMB activity in the diagnosis of small perioperative myocardial infarctions after bypass surgery.     

Midregional proadrenomedullin reflects cardiac dysfunction in haemodialysis patients with cardiovascular disease.

BACKGROUND: Although adrenomedullin is an indicator of cardiac dysfunction in haemodialysis patients, the clinical significance of midregional proadrenomedullin has not been elucidated. Objectives. We evaluated whether midregional proadrenomedullin reflects cardiac dysfunction, systemic inflammation or blood volume in haemodialysis patients. METHODS: Plasma midregional proadrenomedullin, C-reactive protein and delta body weight (indicating excessive blood volume), and two-dimensional as well as Doppler echocardiographic variables were measured just before haemodialysis in 70 patients with cardiovascular disease. RESULTS: The median value of midregional proadrenomedullin was 1.93 nmol/l before haemodialysis, and these levels were significantly reduced following haemodialysis. Log [midregional proadrenomedullin] was positively correlated with left ventricular end-systolic volume index, diameter of inferior vena cava, C-reactive protein and delta body weight (r = 0.328, r = 0.421, r = 0.356, r = 0.364), and negatively with blood pressure, deceleration time of an early diastolic filling wave, pulmonary venous flow velocity ratio and left ventricular ejection fraction (r = -0.330, r = -0.324, r = -0.479, r = -0.373). Multivariate regression analysis revealed that pulmonary venous flow velocity ratio, diameter of inferior vena cava and C-reactive protein were independently related factors for midregional proadrenomedullin concentration. CONCLUSION: Plasma midregional proadrenomedullin levels increase in association with cardiac dysfunction, systemic inflammatory status and systemic blood volume in haemodialysis patients with concomitant cardiovascular disease.     

Assessment of myocardial injury by troponin T in off-pump coronary artery grafting and conventional coronary artery graft surgery

Purpose : The present study was undertaken to assess the degree of myocardial injury, using troponin T (TnT), in off‐pump coronary artery surgery (OPCAB) and in a comparable patient group undergoing conventional coronary artery graft surgery (CABG). Methods : Twenty‐seven OPCAB and 27 CABG patients were investigated. Blood samples for TnT were taken at intubation and at 12, 24 and 72 h. Nine patients (five OPCAB, four CABG) underwent 2 h sampling for 12 h for the assessment of the TnT release profile. All patients had an electrocardiogram performed preoperatively and on the mornings of days 1 and 5 postoperatively. Results : The OPCAB group had significantly greater Canadian Heart Classification 3 patients (P = 0.003); however, other demographic data were similar between the two groups. All patients had normal TnT at initial sampling. The mean number of grafts in each group was 1.8 ± 0.6 for OPCAB and 1.9 ± 0.3 for CABG (P = NS). There were two new Q wave myocardial infarctions in the CABG group and none in the OPCAB group. These cases were excluded from biochemical analyses. Troponin T release was significantly less in the OPCAB group at 12 and 24 h (P < 0.001 and P = 0.03, respectively). Peak TnT release occurred at 6–8 h in both groups. Troponin T release was significantly lower in the OPCAB group at 2, 4, 6, 8, 10 and 12 h (P = 0.01, P = 0.03, P = 0.02, P = 0.02, P = 0.03 and P = 0.04, respectively). Postoperatively, the OPCAB group required less blood transfusion (P = 0.02). Conclusions : The OPCAB group demonstrated a significantly reduced TnT release profile compared with the CABG group.