Georg Hess

Comparison of the new high sensitive cardiac troponin T with myoglobin, h-FABP and cTnT for early identification of myocardial necrosis in the acute coronary syndrome.

BackgroundWe sought to determine the performance of the new high sensitivity cardiac troponin T assay (TnThs) for early diagnosis of myocardial infarction in patients with suspected acute coronary syndrome (ACS) and compare it with the fourth generation cTnT assay, myoglobin and heart-type fatty acid binding protein (h-FABP).MethodsNinety-four patients with diagnosis of suspected ACS without ST-segment elevation admitted to our chest pain unit were included. Patients were divided according to time from onset of symptoms to presentation into an early presenter group (<4xa0h) and a late presenter group (≥4xa0h). A median of six samples (range 2–8) were available per patient. The diagnostic performance of TnThs was assessed using ROC analysis. Areas under the curve (AUC) of baseline and follow-up results of TnThs, cTnT, myoglobin, and h-FABP were compared using c statistics.ResultsThe TnThs assay allows an excellent prediction of non-ST-segment elevation myocardial infarction (non-STEMI) at presentation, particularly among late presenters. A follow-up sample improves diagnostic performance in a time-dependent manner. The AUC of TnThs was superior to cTnT at all time points. The performance of TnThs was at least as good as myoglobin and h-FABP at presentation and during follow-up.ConclusionsA baseline sample of TnThs allows an earlier prediction of non-STEMI than the less sensitive and precise fourth generation cTnT assay. Probably, this excellent performance of TnThs at baseline and follow-up could obviate the need for other early markers of necrosis in future.

Effect of GB Virus C Coinfection on Response to Antiretroviral Treatment in Human Immunodeficiency Virus–Infected Patients

To study how GB virus C (GBV-C) coinfection affects the response to highly active antiretroviral therapy (HAART), 146 human immunodeficiency virus (HIV)-infected patients were tested for GBV-C RNA and antibodies against GBV-C E2 protein, and responses to HAART were evaluated. GBV-C-infected patients exhibited a complete virological response to HAART more often than patients without [correction] GBV-C and had a greater increase in median CD4 cell count and a marginally greater median HIV RNA level decrease. This association was found to be independent of baseline CD4 cell count and plasma HIV RNA, which indicates that an association exists between GBV-C infection and response to HAART.

Effect of stress-induced reversible ischemia on serum concentrations of ischemia-modified albumin, natriuretic peptides and placental growth factor

SummaryObjectiveThere is controversy whether new biomarkers are able to identify myocardial ischemia in the absence of myonecrosis.MethodWe measured NT-pro BNP, NT-pro ANP, ischemia-modified albumin (IMA) and placental growth factor (PlGF) in patients undergoing nuclear stress testing for suspected ischemic heart disease. A thallium scan was used for detection of reversible myocardial ischemia and cardiac troponin T (cTnT) for exclusion of stress-induced myonecrosis. Of 195 patients, 24 with reversible and 62 with no perfusion defect were included in the analysis. Plasma levels were measured before, 18 min and 4 h after stress testing.ResultsOf the 86 patients, 52 received an exercise stress and 34 dipyridamol. New myonecrosis indicated by cTnT could be excluded in all patients. Plasma levels of NT-pro BNP and NT-pro ANP before testing were significantly higher in patients who later developed reversible perfusion defects (NT-pro BNP 139.00 (58.25/367.01) pg/mL vs 327.45 (120.50/972.85) pg/mL, p < 0.05; NT-pro ANP 732.5 (470.0/ 1220.0) pg/mL vs 1470.0 (694.0/ 1910.0) pg/mL, p < 0.05). Plasma levels of NT-pro BNP, NT-pro ANP and PIGF did not change significantly after stress testing, IMA levels rose significantly after 4 h in patients with and without reversible perfusion defects.ConclusionThe elevation of NTpro BNP and NT-pro ANP at baseline may represent the cumulative effect of repeated bouts of myocardial ischemia. A single brief episode of provoced ischemia does not cause a significant increase of the measured biomarkers beside from IMA after exercise stress test potentially indicating skeletal muscle ischemia.

NT-proBNP is increased in healthy pregnancies compared to non-pregnant controls

Serum concentrations of the amino‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) may be used to monitor cardiac function during pregnancy but normal values are not established for this purpose. Therefore, we investigated NT‐proBNP in normotensive healthy pregnancies compared to a non‐pregnant control group. Serum NT‐proBNP was measured in 94 normotensive, healthy pregnant women (32±6 years) every five weeks beginning from 12th gestational week (GW) in a longitudinal study and compared to a non‐pregnant control group of 521 women (32±7 years). Pooled median serum NT‐proBNP levels (25th; 75th percentile) were significantly higher in pregnant women compared to non‐pregnant women (56 (33; 95) pg/ml vs. 38 (22; 62) pg/ml (p<0.001)). NT‐proBNP increased during pregnancy to 73 (51; 124) pg/ml in the 11+6 to 15+6 GW (p<0.001). However, NT‐proBNP levels from 23+0 GW towards term were comparable to non‐pregnant controls. NT‐proBNP is significantly elevated in healthy pregnancies until mid‐pregnancy. As preeclampsia and gestational hypertension are associated with increased NT‐proBNP, our results have to be considered in future diagnostic approaches using NT‐proBNP for these pathologic conditions.

Active or Prior GB Virus C Infection Does Not Protect against Vertical Transmission of HIV in Coinfected Women from Tanzania

To determine whether GB virus C (GBV-C) infection is associated with protection against vertical transmission of human immunodeficiency virus (HIV), we tested 186 HIV-positive pregnant women for GBV-C. Neither active nor prior GBV-C infection was associated with a lower rate of HIV acquisition among infants. Thus, GBV-C does not appear to protect against perinatal HIV acquisition.

Reference change values and determinants of variability of NT-proANP and GDF15 in stable chronic heart failure.

Biovariability, reference change values (RCV), and index of individuality (IOI) have not been previously described for NT-proANP or GDF15. Also, the relation of changes of these markers to other clinical variables or biomarkers is unknown. In 41 patients with stable chronic systolic dysfunction, NT-proANP and GDF15 were measured alongside with clinical variables/markers comprising NT-proBNP, hsTnT, and hsCRP at four sampling intervals (2xa0weeks, 1-, 2-, 3-month intervals). At 2 weeks, 1-, 2-, and 3-month-follow-up, individual NT-proANP variations were 27.1, 22.5, 28.9, 15.6%, respectively, corresponding to RCVs of 53.2, 62.4, 80.2, and 43.2%, respectively. For GDF15, the respective individual variations were 6.8, 4.1, 5.5, 6.8%, corresponding to RCVs of 18.8, 11.5, 15.3 and 18.8%. Neither changes of NT-proANP or GDF15 correlated with changes in any of the clinical variables or biomarkers examined except for GDF15 with renal function. Baseline hormonal levels and clinical variables did not consistently influence the extent of change. The IOI was 0.19–0.35 according to interval for NT-proANP and 0.06–0.09 for GDF 15. In patients with CHF preselected for clinical stability changes of NT-proANP at intermediate follow-up do not correlate with changes in other variables; changes of GDF15 inversely correlate with renal function. The extent of change in both markers is not related to baseline hormonal levels or other baseline variables. RCVs are high for NT-proANP and low for GDF15, while inter-individual variation is high in GDF15 and intermediate in NT-proANP.

Biological variation of high sensitive Troponin T in stable heart failure patients with ischemic or dilated cardiomyopathy

IntroductionHigh sensitive Troponin (hsTn) assays enable detection of minimal marker elevation in heart failure patients previously deemed Troponin negative. Biovariability, reference change values (RCV), and index of individuality (II) have not been previously described for hsTnT although serial testing is important in interpreting low concentrations. For these values, a difference between ischemic heart disease (IHD) and dilated cardiomyopathy (dCMP) appears conceivable.MethodsChange in hsTnT was determined alongside with clinical variables in 41 patients with stable chronic systolic dysfunction at 2-week-, 1-month-, 2-month-, and 3-month-intervals (IHD nxa0=xa017; dCMP nxa0=xa024).ResultsHsTnT was detectable in all patients. Individual hsTnT-variations at 2-week, 1-month, 2-month, and 3-month follow-up were 7.2, 22.6, 28.9, and 15.7%, respectively, corresponding to RCVs of 20.1, 62.5, 80.0, and 43.3%, respectively, for crude values. For log-normalised values, individual variations were 3.2, 2.8, 2.7, and 3.5%, respectively, corresponding to RCVs of 8.8, 7.9, 7.6, and 9.7%, respectively. The II was 0.03 to 0.33 according to interval. Aetiology of heart failure was not a consistent determinant of variation (pxa0=xa00.28; pxa0=xa00.07; pxa0=xa00.98; pxa0=xa00.03 for 2-week, 1-month, 2-month, and 3-month follow-up, respectively).ConclusionWhile short-term biological variation of hsTnT is low, it becomes relatively more important for intermediate follow-up. It is not related to aetiology of heart failure. The corresponding indices of individuality indicate high individuality of values.

Hepatitis G virus RNA is common in AIDS patients' plasma but is not associated with abnormal liver function tests or other clinical syndromes

Hepatitis G virus (HGV) is a new virus found in 1% to 4% of blood from all donors but is more prevalent in some immunocompromised groups, with unclear clinical significance. Frozen plasma samples from 192 AIDS patients were tested for HGV RNA; 44 (23%) were positive. Positive patients did not differ from negative patients in age, gender, race, HIV infection risk factors, nor blood transfusion exposure. Hepatitis BsAg was associated with HGV infection (odds ratio [OR] = 7.7; 95% confidence interval [CI], 2.4-25.0) but hepatitis C antibody was not. Mean values for liver function tests and hematologic values did not differ significantly between the groups nor did the occurrence of certain recognized AIDS-related complications. Mean CD4+ cell counts and HIV-1 plasma RNA levels were comparable in the two groups, but the mean circulating CD8+ cell count in the HGV-positive group (853+/-458 cells/microL) was higher than in the negative group (682+/-457 cells/microL; p = .03). Hepatitis G virus, although common in AIDS patients, does not appear to alter the course of AIDS nor appear as a distinct hepatitis syndrome.

Biological variation of the cardiac index in patients with stable chronic heart failure: inert gas rebreathing compared with impedance cardiography†

In chronic heart failure (CHF), changes in cardiac function define the course of the disease. The cardiac index (CI) is the most adequate indicator of cardiac function. Interpretation of serial CI measurements, however, requires knowledge of the biological variation of CI. Because measurements of CI can be confounded by the clinical situation or the method applied, biological variation might be subject to the same confounders.

Hemodynamic Determinants of the Biologic Variation of N-Terminal Pro–B-Type Natriuretic Peptide in Patients With Stable Systolic Chronic Heart Failure

BACKGROUND CONTEXTnBiologic variation of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in chronic heart failure (CHF) may affect blood levels and risk stratification. The sources of NT-proBNP variation are unknown.nnnMETHODS AND RESULTSnWe performed NT-proBNP measurements and clinical and hemodynamic assessments in 50 patients with heart failure with reduced ejection fraction (HFrEF) who met criteria for clinical stability over 2 time intervals. Hemodynamic variables were measured with the use of inert gas rebreathing and impedance cardiography. Heart rhythm was monitored with the use of external electrocardiographic event recorders throughout the study. Determinants of NT-proBNP-levels and both absolute (ΔNT-proBNPabs) and relative (ΔNT-proBNP%) changes at 1-week and 2-week intervals were identified with the use of univariable and multivariable linear mixed-effects models and linear regression analyses, respectively. Clinical and hemodynamic variables did not significantly change between study visits. The individual variation of NT-proBNP at 2 weeks was 9.2% (range 3.9%-18.6%). Weight and glomerular filtration rate were independently associated with baseline NT-proBNP concentrations (Pu2009=u2009.01 and Pu2009=u2009.005, respectively). There was no relationship between absolute and relative changes of NT-proBNP at 1-week intervals and changes in clinical and hemodynamic variables. Absolute change of NT-proBNP at 2-week intervals was associated with absolute change in left cardiac work index (Pu2009=u2009.008), and relative change in NT-proBNP at 2-week intervals was determined by relative change of thoracic fluid content index (Pu2009=u2009.008) and diastolic blood pressure (Pu2009=u2009.01). The coefficients of determination (R2) for the multivariable models with Δ1wkNT-proBNPabs, Δ2-weeksNT-proBNPabs, Δ1wkNT-proBNP%, and Δ2wksNT-proBNP% as dependent variables were 0.21, 0.19, 0.10, and 0.32, respectively.nnnCONCLUSIONSnIn patients with stable HFrEF, changes in clinical and hemodynamic variables only marginally contribute to the variation of NT-proBNP.