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Biomedical subjects

M Müller-Bardorff

Publications and source records attributed to M Müller-Bardorff.

At least 19 recordsLinked to original sources
PubMed2002

[Suspected acute coronary syndrome in patients without ST-elevation. Exclusion of infarction, early clinical estimation and non-coronary diagnoses].

BACKGROUND AND OBJECTIVE: Patients admitted to the hospital with suspected acute coronary syndrome (ACS) represent a collective at high risk. The NOWIS substudy aimed at evaluating 3 points: (1) Safe exclusion of myocardial infarction by history, symptoms, biochemical markers and the ECG, (2) value of the first diagnosis by the physician in the emergency room, and (3) prevalence and distribution of non-coronary leading diagnoses. PATIENTS AND METHODS: In 164 patients admitted with suspected ACS without ST-segment elevation (73 % men, median age 66 years) the cardiac markers myoglobin, troponin T and CK/CK-MB were assessed on admission and 4 h later. In 2 of the NOWIS centers, the diagnosis on admission, derived from the ECG, history and clinical symptoms, was compared with the leading diagnosis at discharge, based on coronary angiography and, if negative, on additional esophago-gastroscopy. RESULTS: (1) Myoglobin was the biochemical marker with the highest sensitivity 4 h after admission for acute myocardial infarction (classic) definition by CK-MB elevation) with 90.4 %, followed by troponin T with 84.6 %. Four h after admission, in 15.4 % of the infarction patients (prevalence 31.7 %) troponin T was normal. (2) The admission diagnosis instable angina pectoris was confirmed in 46.7 % (57 of 122), suspected acute infarction in 76.2 % (32 of 42). On the other hand, 90.4 % (57 of 63) of the patients with instable angina as leading diagnosis at discharge were correctly diagnosed on admission, but only 61.5 % (32 of 42) of the patients with infarction. (3) At discharge, 29.9 % (49 of 164) of the patients had a non-coronary leading diagnosis. Here, the most common were gastro-intestinal (55.1 %), costo-vertebral (18.4 %) and broncho-pulmonary (16.3 %). CONCLUSIONS: (1) Troponin and myoglobin are helpful in patients without ST-segment elevation; yet, 4 h after admission, a safe exclusion of myocardial infarction is not possible. (2) The clinical diagnosis on admission is important. However, it corresponds with the leading diagnosis at discharge, based on coronary angiography, in only 50 to 75 %. Patients admitted with suspected ACS should be monitored for 24 h in the hospital (chest pain units or coronary care units). (3) Nearly one third of the patients initially admitted with suspected ACS show a non-coronary leading diagnosis, thus underlining the value of further investigations and of an interdisciplinary approach.

Acute Disease↗
PubMed2001

Admission troponin T level predicts clinical outcomes, TIMI flow, and myocardial tissue perfusion after primary percutaneous intervention for acute ST-segment elevation myocardial infarction.

BACKGROUND: In ST-segment elevation myocardial infarction, a troponin T >/=0.1 microg/L on admission indicates poorer prognosis despite early reperfusion. To evaluate the underlying reason, we studied the value of cardiac troponin T (cTnT) for prediction of outcomes, epicardial blood flow, and myocardial reperfusion after primary percutaneous intervention. METHODS AND RESULTS: Patients (n=140) admitted within 12 hours after onset of symptoms were stratified by admission cTnT. Epicardial and myocardial reperfusion were graded by the TIMI score and by measurement of relative increases of myoglobin, cTnT, and creatine kinase (CK)-MB 60 minutes after recanalization, respectively. cTnT was positive in 64 patients (45.7%) and was associated with longer median time intervals to admission (5.5 versus 3.5 hours, P<0.001) and higher mortality rates after 30 days (12.5% versus 3.9%, P=0.06) and 9 months (14% versus 3.9%, P=0.005). cTnT independently predicted a 3.2-fold risk for incomplete epicardial reperfusion (P=0.03). In addition, cTnT >/=0.1 microg/L was associated with more severely impaired myocardial perfusion despite normal epicardial flow, as indicated by lower 60-minute ratios of myoglobin (2.6 versus 7.6, P=0.007), cTnT (6.6 versus 29.2, P<0.001), and CK-MB (3.5 versus 21.4, P=0.002) and a tendency for less resolution of ST-segment elevations (54% versus 60%, P=0.08). CONCLUSIONS: cTnT predicts poorer clinical outcomes, lower rates of postprocedural TIMI 3 flow, and more severely compromised myocardial perfusion despite normal epicardial flow. Thus, a cTnT-positive patient may require more aggressive adjunctive therapy when treated by percutaneous coronary intervention. The impact of preexisting or evolving microvascular dysfunction and the effect of therapies that target myocardial perfusion require further prospective evaluation.

Aged↗
PubMed2001

Recalibration of the point-of-care test for CARDIAC T Quantitative with Elecsys Troponin T 3rd generation.

The rapid troponin T assay CARDIAC T Quantitative was recalibrated using Elecsys Troponin T 3rd Generation as a new reference method. This paper presents the method comparisons at six centres using the new reference method. Method comparison between CARDIAC T Quantitative versus Elecsys Troponin T 3rd Generation were performed using 319 samples from patients with acute coronary syndromes. The quality of the CARDIAC T Quantitative was controlled by a daily single determination of CARDIAC Control Troponin T, and for the Elecsys Troponin T 3rd Generation, the Elecsys controls were included in each run. The results for the control materials for the CARDIAC T Quantitative were between 93% and 107% of the target values. The CV ranged from 7% to 16%. From the regression analysis, according to Bablok and Passing (y=1.07x) and the Bland and Altman plot, the bias between CARDIAC T Quantitative and Elecsys Troponin T 3rd Generation is from +6% to +7%. The correlation coefficient is 0.93, and a 3x3 comparison of the clinical efficiency yielded 92% clinical concordance between CARDIAC T Quantitative and Elecsys Troponin T 3rd Generation. In conclusion, CARDIAC T Quantitative was in good agreement with the reference and calibration method Elecsys Troponin T 3rd Generation.

Calibration↗
PubMed2001

Evaluation of CoaguChek Pro ACT in cardiac catheterization laboratory.

The objective of this study was to assess the analytical performance of CoaguChek Pro ACT assay versus Hemochron Celite ACT assay concerning activated clotting time (ACT) values and the correlations versus heparin. Enrolled were 158 patients and 101 normal subjects from five cardiac catheterization laboratories (cathlabs). Two different CoaguChek Pro ACT lots were compared to different lots of Hemochron Celite ACT. All sites used arterial blood and one site also used venous blood. Determinations were carried out before and directly after heparinization, and 1-4 h later. Besides the ACT values, hematocrit, platelet counts and factor Xa levels were also determined. The correlations between the Hemochron Celite lots and the two different CoaguChek Pro lots for arterial and venous blood for all sites were good (r=0.88 and 0.84). The agreement between both CoaguChek Pro ACT lots was excellent (r=0.99). The correlations between heparin and CoaguChek Pro ACT were similar to those for the Hemochron Celite lots. There was no influence of the hematocrit and the platelets. The imprecision of the method was very good (CV<6%). This demonstrates that the CoaguChek Pro ACT assay is especially useful for monitoring heparin in cathlabs.

Cardiac Catheterization↗
PubMed2000

Diagnostic and prognostic role of myoglobin in patients with suspected acute coronary syndrome. North-Württemberg Infarction Study (NOWIS) Group.

In patients with suspected acute coronary syndrome, myoglobin is, according to IFCC and NACB guidelines, the marker of choice for early determination of acute infarction, in particular in combination with creatine kinase-MB, 4 hours after admission with a sensitivity of 96%, and correctly excludes Q-wave infarctions. In patients without acute myocardial infarction, a positive troponin T (relative risk 31.5%), but not an elevated myoglobin (relative risk 4.5%), is highly predictive for adverse in-hospital outcome.

Angina, Unstable↗
PubMed2000

Risk stratification in patients with inferior acute myocardial infarction treated by percutaneous coronary interventions: the role of admission troponin T.

BACKGROUND: Cardiac troponin T (cTnT) elevations on admission indicate a high-risk subgroup of patients with ST-segment elevation acute myocardial infarction (AMI). This finding has been attributed to less effective reperfusion after thrombolytic therapy. The aim of this study was to determine the role of admission cTnT on the efficacy of percutaneous coronary interventions (PCIs) in inferior AMI. METHODS AND RESULTS: One hundred fifty-nine consecutive patients with inferior ST-segment AMI were enrolled and followed up for a mean of 448 days. Patients were stratified by cTnT on admission. A cTnT >/=0.1 microg/L was found in 58% of patients. These patients had longer time intervals from onset of symptoms to therapy (P:<0. 001) and higher 30-day (10.8% versus 1.5%, P:=0.027) and long-term (17.2% versus 4.5%, P:=0.023) cardiac mortalities. Rates of the combined end point of death, nonfatal reinfarction, and need for repeated target vessel revascularization procedures were not different in cTnT groups (log rank, 0.69; P:=0.41). PCI was attempted in 93.3% of cTnT-positive and 98.5% cTnT-negative patients (P:=0.24) but was less frequently successful in patients with cTnT >/=0.1 microg/L (77.9% versus 96.9%, P:<0.001). Coronary stenting reduced 30-day and long-term cardiac mortality, particularly among cTnT-positive patients. In a multivariate analysis, cTnT indicated an approximately 5-fold-higher risk (adjusted OR, 4.6; 95% CI, 0.79 to 27.11; P:=0.089) and was a strong albeit not independent risk predictor. CONCLUSIONS: In inferior AMI, a positive admission cTnT is associated with lower success rates of direct PCI and higher rates of cardiac events over the short and long term. These patients benefit from coronary stenting.

Acute Disease↗
PubMed2000

Independent prognostic value of cardiac troponin T in patients with confirmed pulmonary embolism.

BACKGROUND: Cardiac troponin T (cTnT) is a sensitive and specific marker, allowing the detection of even minor myocardial cell injury. In patients with severe pulmonary embolism (PE), myocardial ischemia may lead to progressive right ventricular dysfunction. It was therefore the purpose of this study to test the presence of cTnT and its prognostic implications in patients with confirmed PE. METHODS AND RESULTS: Fifty-six consecutive patients with confirmed PE were enrolled in this prospective study. PE was confirmed by pulmonary angiography, lung scan, or echocardiography and subsidiary analyses. Severity of PE was assessed by a clinical scoring system, and cTnT was measured within 12 hours after admission. cTnT was elevated (>/=0.1 microg/L) in 18 (32%) patients with massive and moderate PE but not in patients with small PE. In-hospital death (odds ratio 29. 6, 95% CI 3.3 to 265.3), prolonged hypotension and cardiogenic shock (odds ratio 11.4, 95% CI 2.1 to 63.4), and need for resuscitation (odds ratio 18.0, 95% CI 2.6 to 124.3) were more prevalent in patients with elevated cTnT. cTnT-positive patients more often needed inotropic support (odds ratio 37.6, 95% CI 5.8 to 245.6) and mechanical ventilation (odds ratio 78.8, 95% CI 9.5 to 653.2). After adjustment, cTnT remained an independent predictor of 30-day mortality (odds ratio 15.2, 95% CI 1.22 to 190.4). CONCLUSIONS: cTnT may improve risk stratification in patients with PE and may aid in the identification of patients in whom a more aggressive therapy may be warranted.

Aged↗
PubMed2000

Time-dependent diagnostic performance of a rapid troponin T version 2 bedside test in patients with acute coronary syndromes.

In a prospective trial, the diagnostic performance of the second version of the troponin T rapid assay (Trop T; cutoff 0.2 microg/L) was compared with the quantitative cardiac-specific troponin T assay (cTnT ELISA; cutoff 0.1 microg/L) and other established cardiac markers such as CK, CK-MB activity, CK-MB mass and myoglobin. Additionally, a 30-day follow-up was performed to determine the suitability of the Trop T assay and the reference markers for short-term risk stratification. Two-hundred-and-eighty-six consecutive patients with chest pain and suspected acute myocardial infarction (AMI) were enrolled in two CCU departments. Serial blood specimens were taken at admission and at 3, 6, 12, 24, 48, 72 and 96 h after admission. According to the biochemical criterion CK-MB mass, the patients were classified as having AMI in 154 patients (54%), unstable angina (UAP) in 72 patients (27%) and no evidence for acute cardiac ischemia in 55 patients (19%). Analytical method comparison of Trop T with cTnT ELISA (cutoff 0.1 microg/L) showed a good agreement, Trop T yielded only 4% false-negative and 3% false-positive results. The diagnostic performance of Trop T for the detection of AMI was only slightly inferior compared to cTnT ELISA. Beyond 12 h after admission, Trop T and cTnT ELISA maintained a sensitivity close to 100%, whereas the sensitivity of the other cardiac markers decreased sharply. The diagnostic sensitivity of Trop T for the detection of minor myocardial damage in UAP patients was the same as for cTnT ELISA. Death within 30 days' follow-up occurred only in AMI patients with a positive Trop T test result within the first 6 h after admission. The admission Trop T and cTnT ELISA were the only significant biochemical predictors of major cardiac events. In conclusion, these data show that Trop T has similar diagnostic sensitivity as cTnT ELISA and is a useful tool to confirm acute or subacute myocardial infarction. Trop T is an excellent marker in detecting minor myocardial damage in UAP patients and is suitable for short-term risk stratification.

Angina, Unstable↗
PubMed2000

Cardiac troponin T levels at 96 hours reflect myocardial infarct size: a pathoanatomical study.

We determined the utility of single-point measurements of circulating cardiac troponin T (cTnT) for the noninvasive estimation of infarct size in 16 beagle dogs after left anterior descending artery (LAD) ligation. Pathoanatomical infarct sizes were determined by the triphenyltetrazolium chloride method and correlated with serum concentration changes of cTnT. Peak cTnT levels (14.10 +/- 4.71 microg/l) were reached after 110 +/- 21 h. A significant correlation was found between peak cTnT levels (p = 0.0001, r = 0. 83) or cumulative cTnT levels and relative infarct size (p = 0.0010, r = 0.72). A single cTnT measurement 96 h after LAD ligation was equally predictive of infarct size (p = 0.0010, r = 0.74) as peak or cumulative cTnT levels derived from serial sampling. cTnT levels at 96 h may thus be useful for practical and cost-effective estimation of infarct size.

Animals↗
PubMed2000

Evaluation of a point-of-care system for quantitative determination of troponin T and myoglobin.

We present the results of a multicenter evaluation of a new point-of-care system (Cardiac Reader) for the quantitative determination of cardiac troponin T (CARDIAC T Quantitative test) and myoglobin (CARDIAC M test) in whole blood samples. The Cardiac Reader is a CCD camera that optically reads the immunochemical test strips. The measuring range is 0.1 to 3 microg/l for CARDIAC T Quantitative and 30 to 700 microg/l for CARDIAC M. Both tests are calibrated by the manufacturer. The reaction times of the tests are 12 or 8 minutes, respectively. Method comparisons were performed with 281 heparinized blood samples from patients with suspected acute coronary syndromes. The results obtained with CARDIAC T Quantitative showed a good agreement compared with cardiac troponin T ELISA (r = 0.89; y = 0.93x + 0.02). The method comparison between CARDIAC M and Tina-quant Myoglobin also showed a good agreement between both assays (r = 0.98; y = 0.92x + 1.6). Test lot-to-lot comparisons yielded differences of 2% and 6% for CARDIAC T Quantitative and of 0 to 11% for CARDIAC M. The within-run imprecision with blood samples and control materials was acceptable for CARDIAC T Quantitative (CV 10 to 15%) and good for CARDIAC M (CV 5 to 10%). The between-instrument CV was below 7% for CARDIACT Quantitative and below 5% for CARDIAC M. The cross-reactivity of CARDIAC T Quantitative with skeletal troponin T was approximately 0.003%. No significant analytical interference was detected for any of the assays in investigations with biotin (up to 100 microg/l), hemoglobin (up to 0.125 mmol/l), hematocrit (26 to 52%), bilirubin (up to 340 micromol/l), triglycerides (up to 5.0 mmol/l), and 18 standard drugs. With the Cardiac Reader reliable quantitative results can be easily obtained for both cardiac markers. The system is, therefore, particularly suitable for use in emergency rooms, coronary care units and small hospitals.

Coronary Disease↗
PubMed2000

Analytical and clinical performance of an improved qualitative troponin T rapid test in laboratories and critical care units.

OBJECTIVE: To evaluate the performance of a visual troponin T rapid test in the hands of nontraditionally trained personnel of 2 critical care units in comparison to 3 laboratories. METHODS: Method comparisons of the troponin T rapid test versus cardiac troponin T enzyme-linked immunosorbent assay were performed with 804 samples from 510 patients with suspected acute coronary syndromes. Cross-reactivity with skeletal troponin T was studied up to 5000 microg/L. RESULTS: Laboratories and critical care units obtained comparable results in the analytical cutoff of the test (0.11 and 0. 10 microg/L) and in the diagnostic sensitivities in the detection of acute myocardial infarction (96% and 93% after 8 hours) and of high-risk patients with unstable angina pectoris (100% and 100%). Different percentages of false-positive results (0.2% and 3%) were found, which may reflect different objectives and strategies in these hospital units. The cross-reactivity with skeletal troponin T was less than 0.01%. CONCLUSIONS: The troponin T rapid test gives reliable results not only when used by laboratory personnel experienced in the execution of analytical methods, but also in the hands of nurses and physicians working in clinical units outside the laboratory.

Angina, Unstable↗
PubMed2000

Troponin T and I assays show decreased concentrations in heparin plasma compared with serum: lower recoveries in early than in late phases of myocardial injury.

BACKGROUND: Heparinized plasma samples allow more rapid analysis than serum samples, but preliminary studies showed lower cardiac troponin T (cTnT) results in plasma. We undertook a multicenter study to characterize this effect for cTnT and cardiac troponin I (cTnI). METHODS: Blood samples were collected with and without heparin at five hospitals. cTnT was measured by a "third generation" assay (Elecsys((R))), and cTnI was measured by a commercial immunoassay (IMMULITE((R))). RESULTS: Mean cTnT was 15% lower in heparin sampling tubes than in serum. Measured concentrations of cardiac troponins also decreased with increasing heparin concentrations added to sera. Heparin-induced losses were greater in early than in late phases after onset of chest pain. Addition of heparin ( approximately 100 IU/mL) to serial samples from nine acute myocardial infarction patients produced mean cTnT losses of 33% at 1-12 h after onset of chest pain, 17% at 13-48 h, and 7% after 48 h. The changing heparin effects were seen for both cTnT and cTnI during time courses of individual patients with myocardial infarction. CONCLUSION: We suggest that binding of heparin to troponins decreases immunoreactivity, especially in early phases of myocardial injury. The resulting losses may depend on the antibodies used in each troponin assay.

Anticoagulants↗
PubMed1999

Quantitative bedside assay for cardiac troponin T: a complementary method to centralized laboratory testing.

BACKGROUND: In the evaluation of chest pain patients, whole blood bedside assays of highly specific cardiac molecules may be an attractive alternative to centralized clinical chemistry testing. We now report on an optimized test strip device for cardiac troponin T (cTnT) that can be analyzed by a cardiac reader for quantitative assessment of the test result. METHODS AND RESULTS: The cTnT test strip reader measures, via a CCD camera, the reflectance of the signal line. For quantitative analysis, a calibration curve was constructed from 1030 samples of 252 consecutive patients with acute coronary syndromes. In a method comparison of 140 samples, the quantitative results of the cTnT test strip reader correlated closely with the results of the cTnT ELISA (r = 0.98; y = 0.85x + 0. 002). Within-run and day-to-day (n = 10) mean CVs were between 11% and 16%, respectively. The cross-reactivity with skeletal troponin T was <0.02%. In patients with myocardial infarction, 45% and 91% of all samples were positive on admission and at 4-8 h after the onset of symptoms, respectively. ROC curve analysis demonstrated a comparable efficiency of the cTnT test strip reader and the laboratory-based cTnT ELISA in patients with suspected myocardial infarction. CONCLUSIONS: It is now possible to quantitatively determine cTnT at the patient's bedside with a rapid and convenient test device. This will facilitate the diagnostic work up of patients with suspected myocardial cell necrosis.

Angina, Unstable↗
PubMed1998

[Value of laboratory parameters in risk assessment of patients with coronary heart disease and chronic myocardial ischemia].

The main purpose of laboratory tests in patients with acute coronary syndromes is the exclusion of an acute myocardial infarction and the detection of myocardial micronecrosis. Patients with minor myocardial cell damage can best be identified by measurement of cardiac troponin T and possibly also cardiac troponin I levels. Other serum markers of acute ischemia lack specificity and are, therefore, currently of little clinical significance.

Blood Chemical Analysis↗
PubMed1998

Elevated serum concentrations of cardiac troponin T in acute allograft rejection after human heart transplantation.

OBJECTIVES: This study evaluates the concept and diagnostic efficacy of using serum troponin T for the detection of cardiac graft rejection. BACKGROUND: Cardiac troponin T is a cardiospecific myofibrillar protein, which is only detectable in the circulation after cardiac myocyte damage. It might be expected to be released during acute heart allograft rejection, allowing noninvasive rejection diagnosis. METHODS: In 35 control subjects and in 422 samples from 95 clinically unremarkable heart allograft recipients more than 3 months postoperatively, troponin T serum concentrations were compared to the histological grade of acute graft rejection in concurrent endomyocardial biopsies. RESULTS: Mean troponin T serum concentrations were identical in control subjects (23.2 +/- 1.4 ng/liter) and in heart transplant recipients without graft rejection (International Society for Heart and Lung Transplantation [ISHLT] grade 0; 22.4 +/- 1.7 ng/liter). Mean troponin T concentrations increased in parallel with the severity of graft rejection (ISHLT grade 1: 27.8 +/- 1.8 ng/liter; grade 2: 33.2 +/- 2.7 ng/liter; grade 3A: 54.6 +/- 6.5 ng/liter; grade 3B and 4: 105.4 +/- 53.7 ng/liter; p < 0.001 for grades 3 and 4 vs. grades 0 and 1). The proportion of positive samples also increased in parallel with rejection severity, reaching 100% in rejections of grade 3B and 4. Sensitivity and specificity for the detection of significant graft rejection (ISHLT grade 3/4) were 80.4% and 61.8%, respectively. The negative predictive value was most remarkable with 96.2%. Intraindividual longitudinal analysis of troponin T levels and biopsy results in 15 patients during long-term follow-up confirmed these findings. CONCLUSIONS: The present data demonstrate that acute allograft rejection after human heart transplantation is often associated with increased serum concentrations of troponin T. All cases of serious forms of graft rejection would have been detected before the development of clinical symptoms. Measurement of troponin T levels may become a useful ancillary parameter for noninvasive rejection diagnosis, being most valuable in the exclusion of severe cardiac graft rejection.

Acute Disease↗
PubMed1998

Cardiac troponin T in patients with end-stage renal disease: absence of expression in truncal skeletal muscle.

In patients with end-stage renal disease (ESRD), the serum concentration of cardiac troponin T (cTnT) may be increased without cardiac ischemia. One reason for this unexplained increase could be the extracardiac expression of cTnT. However, truncal skeletal muscle biopsies of five patients with ESRD showed no evidence of the expression of either cTnT mRNA (reverse transcription-PCR) or protein (immunoblot, immunofluorescence). We also measured the serum concentration of cTnT in 97 patients with ESRD. The serum cTnT concentration determined in both first and second generation cTnT assays was significantly lower P <0.01 in patients with a low cardiac risk than in patients with positive indicators of coronary artery disease. The correlation between cTnT and indicators of coronary artery disease is consistent with the hypothesis that cTnT in the serum of patients with ESRD originates from the heart.

Abdominal Muscles↗