One-year in vitro stability of cardiac troponins and galectin-3 in different sample types

Prognostic significance of chronic myocardial injury diagnosed by three different cardiac troponin assays in patients admitted with suspected acute coronary syndrome

OBJECTIVES

Chronic myocardial injury (CMI) is defined as stable concentrations of cardiac troponin T or I (cTnT or cTnI) above the assay-specific 99th percentile upper reference limit (URL) and signals poor outcome. The clinical implications of diagnosing CMI are unclear. We aimed to assess prevalence and association of CMI with long-term prognosis using three different high-sensitivity cTn (hs-cTn) assays.

METHODS

A total of 1,292 hospitalized patients without acute myocardial injury had cTn concentrations quantified by hs-cTn assays by Roche Diagnostics, Abbott Diagnostics and Siemens Healthineers. The median follow-up time was 4.1 years. The prevalence of CMI and hazard ratios for mortality and cardiovascular (CV) events were calculated based on the URL provided by the manufacturers and compared to the prognostic accuracy when lower percentiles of cTn (97.5, 95 or 90), limit of detection or the estimated bioequivalent concentrations between assays were used as cutoff values.

RESULTS

There was no major difference in prognostic accuracy between cTnT and cTnI analyzed as continuous variables. The correlation between cTnT and cTnI was high (r=0.724-0.785), but the cTnT assay diagnosed 3.9-4.5 times more patients with having CMI based on the sex-specific URLs (TnT, n=207; TnI Abbott, n=46, TnI Siemens, n=53) and had higher clinical sensitivity and AUC at the URL.

CONCLUSIONS

The prevalence of CMI is highly assay-dependent. cTnT and cTnI have similar prognostic accuracy for mortality or CV events when measured as continuous variables. However, a CMI diagnosis according to cTnT has higher prognostic accuracy compared to a CMI diagnosis according to cTnI.

Fermented Rooibos tea (Aspalathus linearis) Ameliorates Sodium Fluoride-Induced Cardiorenal Toxicity, Oxidative Stress, and Inflammation via Modulation of NF-κB/IκB/IκKB Signaling Pathway in Wistar Rats

High dose of fluoride intake is associated with toxic effects on kidney and cardiac tissues. This study evaluated the potential protective effect of fermented rooibos tea (RTE) on sodium fluoride (NaF)-induced cardiorenal toxicity in rats. Male Wistar rats (n = 56) were randomly allocated into one of seven equal groups: control, NaF (100 mg/kg orally), NaF + RTE (2%, w/v), NaF + RTE (4%, w/v), NaF + lisinopril (10 mg/kg orally), 2% RTE, and 4% RTE. The experiment lasted for 14 days and RTE was administered to the rats as their sole source of drinking fluid. NaF induced cardiorenal toxicity indicated by elevated level of urea, creatinine, LDH, creatinine kinase-MB, and cardiac troponin I in the serum, accompanied by altered histopathology of the kidney and heart. Furthermore, levels of H2O2, malondialdehyde, and NO were elevated, while GSH level was depleted in the kidney and heart due to NaF intoxication. Protein levels of c-reactive protein, TNFα, IL-1B, and NF-κB were increased by NaF in the serum, kidney, and heart. RTE at 2% and 4% (w/v) reversed cardiorenal toxicity, resolved histopathological impairment, attenuated oxidative stress and inhibited formation of pro-inflammatory markers. RTE at both concentrations down-regulates the mRNA expression of NF-κB, and upregulates the mRNA expression of both IκB and IκKB, thus blocking the activation of NF-κB signaling pathway. Taken together, these results clearly suggest that the protective potential of rooibos tea against NaF-induced cardiorenal toxicity, oxidative stress, and inflammation may be associated with the modulation of the NF-κB signaling pathway.

Age-Related Differences in the Contribution of Systolic Blood Pressure and Biomarkers to Cardiovascular Disease Risk Prediction: The Atherosclerosis Risk in Communities (ARIC) Study

We sought to determine how biomarkers known to be associated with hypertension-induced end-organ injury complement the use of systolic blood pressure (SBP) for cardiovascular disease (CVD) risk prediction at different ages. Using data from visits 2 (1990 to 1992) and 5 (2011 to 2013) of the Atherosclerosis Risk in Communities (ARIC) study, 3 models were used to predict CVD (composite of coronary heart disease, stroke, and heart failure). Model A included traditional risk factors (TRFs) except SBP, model B-TRF plus SBP, and model C-TRF plus biomarkers (high-sensitivity troponin T [hsTnT] and N-terminal pro-B-type natriuretic peptide [NT-proBNP]). Harrel's C-statistics were used to assess risk discrimination for CVD comparing models B and A and C and B. At visit 2, the addition of SBP to TRF (model B vs model A) significantly improved the C-statistic (∆C-statistic, 95% confidence interval 0.010, 0.007 to 0.013) whereas the addition of hsTnT to TRF (model C vs model B) decreased the C-statistic (∆C-statistic -0.0038, -0.0075 to -0.0001) compared with SBP. At visit 5, the addition of SBP to TRF did not significantly improve the C-statistic (∆C-statistic 0.001, -0.002 to 0.005) whereas the addition of both hsTnT and NT-proBNP to TRF significantly improved the C-statistic compared with SBP (∆C-statistic 0.028, 0.015 to 0.041 and 0.055, 0.036 to 0.074, respectively). In summary, the incremental value of SBP for CVD risk prediction diminishes with age whereas the incremental value of hsTnT and NT-proBNP increases with age.

Variability of cardiac troponin levels in normal subjects and in patients with cardiovascular diseases: analytical considerations and clinical relevance

In accordance with all the most recent international guidelines, the variation of circulating levels of cardiac troponins I and T, measured with high-sensitivity methods (hs-cTnI and hs-cTnT), should be used for the detection of acute myocardial injury. Recent experimental and clinical evidences have demonstrated that the evaluation of hs-cTnI and hs-cTnT variations is particularly relevant: a) for the differential diagnosis of Acute Coronary Syndromes (ACS) in patients admitted to the Emergency Department (ED); b) for the evaluation of cardiovascular risk in patients undergoing major cardiac or non-cardiac surgery, and in asymptomatic subjects of the general population aged >55 years and with co-morbidities; c) for the evaluation of cardiotoxicity caused by administration of some chemotherapy drugs in patients with malignant tumors. The aim of this document is to discuss the fundamental statistical and biological considerations on the intraindividual variability of hs-cTnI and hs-cTnT over time in the same individual. Firstly, it will be discussed in detail as the variations of circulating levels strictly depend not only on the analytical error of the method used but also on the intra-individual variability of the biomarker. Afterwards, the pathophysiological interpretation and the clinical relevance of the determination of the variability of the hs-cTnI and hs-cTnT values ​​ in patients with specific clinical conditions are discussed. Finally, the evaluation over time of the variation in circulating levels of hs-cTnI and hs-cTnT is proposed for a more accurate estimation of cardiovascular risk in asymptomatic subjects from the general population.

Myocardial Injury Thresholds for 4 High-Sensitivity Troponin Assays in U.S. Adults

BACKGROUND

Myocardial injury is currently defined as a cardiac troponin above the sex-specific 99th percentile of a healthy reference population (upper reference limit [URL]).

OBJECTIVES

The purpose of this study was to estimate high-sensitivity (hs) troponin URLs in a representative sample of the U.S. adult population; overall and by sex, race/ethnicity, and age group.

METHODS

Among adults participating in the 1999-2004 National Health and Nutrition Examination Survey (NHANES), we measured hs-troponin T using 1 assay (Roche) and hs-troponin I using 3 assays (Abbott, Siemens, and Ortho). In a strictly defined healthy reference subgroup, we estimated 99th percentile URLs for each assay using the recommended nonparametric method.

RESULTS

Of 12,545 participants, 2,746 met criteria for the healthy subgroup (mean age 37 years, 50% men). The NHANES 99th percentile URL for hs-troponin T (19 ng/L) matched the manufacturer-reported URL (19 ng/L). NHANES URLs were 13 ng/L (95% CI: 10-15 ng/L) for Abbott hs-troponin I (manufacturer: 28 ng/L), 5 ng/L (95% CI: 4-7 ng/L) for Ortho hs-troponin I (manufacturer: 11 ng/L), and 37 ng/L (95% CI: 27-66 ng/L) for Siemens hs-troponin I (manufacturer: 46.5 ng/L). There were significant differences in URLs by sex, but none by race/ethnicity. Furthermore, the 99th percentile URLs for all 4 hs-troponin assays were statistically significantly lower in healthy adults aged <40 years compared with healthy adults ≥60 years (all P < 0.001 by rank sum testing).

CONCLUSIONS

We found URLs for hs-troponin I assays that were substantially lower than currently listed 99th percentile URLs. There were significant differences in hs-troponin T and I URLs by sex and by age group in healthy U.S. adults but none by race/ethnicity.

Cardiac troponin I in healthy Norwegian Forest Cat, Birman and domestic shorthair cats, and in cats with hypertrophic cardiomyopathy

Objectives

The aims of this study were to assess the potential associations between the serum cardiac troponin I (cTnI) concentration in healthy cats and feline characteristics, systolic blood pressure, heart rate (HR), echocardiographic measurements and storage time; and to compare cTnI concentrations in healthy cats with concentrations in cats with hypertrophic cardiomyopathy (HCM), with or without left atrial enlargement (LAE) and in cats with HCM, to assess potential associations between cTnI concentration and echocardiographic variables.

Methods

Cardiac TnI was analysed using an Abbott ARCHITECT ci16200 analyser in serum from prospectively included healthy Norwegian Forest Cat (NF; n = 33), Birman (n = 33) and domestic shorthair (DSH; n = 30) cats, and from 39 cats with HCM, with or without LAE.

Results

In healthy cats, higher cTnI concentrations were found in Birman cats than in NF cats (P = 0.014) and in neutered male cats than in intact females (P = 0.032). Cardiac TnI was positively associated with HR (P <0.0001). In cats with HCM, cTnI concentration was positively associated with left ventricular wall thickness and with left atrial-to-aortic root ratio (all P ⩽0.010). Cats with HCM had higher cTnI concentrations than healthy cats, and cTnI concentrations were higher in cats with HCM and LAE than in those with HCM without LAE (all P = 0.0003).

Conclusions and relevance

Breed and sex may affect serum cTnI concentrations in healthy cats. The cTnI concentration increased with increasing severity of HCM.

Storage conditions, sample integrity, interferences, and a decision tool for investigating unusual high-sensitivity cardiac troponin results

The current definition of high-sensitivity cardiac troponin (hs-cTn) assays is laboratory-based and their analytical attributes and characteristics have drawn significant attention in the literature at least partly due to the lower concentration cut-offs and changes in concentrations (i.e., deltas) employed in different algorithms and pathways to manage patient care. We propose that pre-analytical conditions such as sample type, storage conditions, and other interferences may also have a significant impact on hs-cTn concentrations and clinical management. The purpose of this literature review is to provide a summary of important pre-analytical and interference studies affecting hs-cTn concentrations. A breakdown of the literature for the major diagnostic companies providing core laboratory instrumentation (i.e., Abbott, Beckman, Ortho, Roche, and Siemens) is also provided. Finally, three cases are highlighted where knowledge of pre-analytical factors aids the hs-cTn clinically discordant investigations. This review highlights the importance of pre-analytical variables, especially storage condition, sample handling, and blood tubes used (i.e., sample type) when interpreting hs-cTn assays. Additional studies are needed to further elaborate on pre-analytical variables (i.e., centrifugation, sample type, stability) and interferences for all hs-cTn assays in clinical use, as knowledge of these variables may aid in hs-cTn clinically discordant investigations.

Impact of ultra-low temperature long-term storage on the preanalytical variability of twenty-one common biochemical analytes

OBJECTIVES

Retrospective studies frequently assume analytes long-term stability at ultra-low temperatures. However, these storage conditions, common among biobanks and research, may increase the preanalytical variability, adding a potential uncertainty to the measurements. This study is aimed to evaluate long-term storage stability of different analytes at <-70 °C and to assess its impact on the reference change value formula.

METHODS

Twenty-one analytes commonly measured in clinical laboratories were quantified in 60 serum samples. Samples were immediately aliquoted and frozen at <-70 °C, and reanalyzed after 11 ± 3.9 years of storage. A change in concentration after storage was considered relevant if the percent deviation from the baseline measurement was significant and higher than the analytical performance specifications.

RESULTS

Preanalytical variability (CV_P) due to storage, determined by the percentage deviation, showed a noticeable dispersion. Changes were relevant for alanine aminotransferase, creatinine, glucose, magnesium, potassium, sodium, total bilirubin and urate. No significant differences were found in aspartate aminotransferase, calcium, carcinoembryonic antigen, cholesterol, C-reactive protein, direct bilirubin, free thryroxine, gamma-glutamyltransferase, lactate dehydrogenase, prostate-specific antigen, triglycerides, thyrotropin, and urea. As nonnegligible, CV_P must remain included in reference change value formula, which was modified to consider whether one or two samples were frozen.

CONCLUSIONS

After long-term storage at ultra-low temperatures, there was a significant variation in some analytes that should be considered. We propose that reference change value formula should include the CV_P when analyzing samples stored in these conditions.

Abdominal aortic calcification, cardiac troponin I and atherosclerotic vascular disease mortality in older women

OBJECTIVE

Examine if two inexpensive measures of atherosclerotic vascular diseases (ASVD), abdominal aortic calcification (AAC) and high-sensitivity cardiac troponin I (hs-cTnI) provide complementary information for 10-year ASVD mortality and all-cause mortality risk in older women.

METHODS

908 community-dwelling women without prevalent ASVD (≥75 years) were followed-up between 2003 and 2013. AAC and plasma hs-cTnI measures were obtained in 2003. AAC was assessed on lateral spine images using a semiquantitative method (AAC24). Linked health records were used for mortality outcomes.

RESULTS

Mean±SD age was 79.9±2.6 years. 276 (30.4%) women died during follow-up, including 138 (15.2%) ASVD-related deaths. AAC24 and hs-cTnI were independently associated with ASVD and all-cause mortality (p<0.001). The cohort was dichotomised into four groups: (1) low AAC24 (AAC24: 0 or 1) and <median hs-cTnI (n=163, referent), (2) moderate-extensive AAC24 (AAC24:>1) and <median hs-cTnI (n=280), (3) low AAC24 and ≥median hs-cTnI (n=148) and (4) moderate-extensive AAC24 and ≥median hs-cTnI (n=317). Compared with the referent group, a stepwise increase in relative hazard (HR (95% CI)) for ASVD mortality was seen at 2.39 (1.05 to 5.46), 3.18 (1.35 to 7.79) and 5.38 (2.44 to 11.85), respectively. A similar associations were observed for all-cause mortality, at 1.58 (0.99-2.52), 2.38 (1.46-3.89) and 3.02 (1.93-4.72), respectively (all p<0.05).

CONCLUSION

Higher AAC and elevated hs-cTnI were associated with higher risk of ASVD mortality and all-cause mortality, independent of each other. Stratifying by moderate to extensive AAC and elevated hs-cTnI identified women at very high risk. Further studies investigating whether combining factors may improve risk prediction are needed.

TRIAL REGISTRATION NUMBER

ACTRN12617000640303.

Glycemic excursions and subclinical cardiac damage in adults with type 2 diabetes: Results from the ADVANCE Trial

We found that 1,5-anhydroglucitol-a marker of glucose excursions-was not independently associated with subclinical cardiac damage, nor with vascular outcomes, in the ADVANCE Trial. High-sensitivity cardiac troponin T and N-terminal pro-b-type natriuretic peptide provided better prognostic information regarding vascular risk in diabetes than 1,5-anhydroglucitol.

Relation of Biomarkers of Cardiac Injury, Stress, and Fibrosis With Cardiac Mechanics in Patients ≥ 65 Years of Age

High sensitivity cardiac troponin T (hscTnT), soluble ST2 (sST2), N-terminal B-type natriuretic peptide (NT-proBNP), and galectin-3 are biomarkers of cardiac injury, stress, myocardial stretch, and fibrosis. Elevated levels are associated with poor outcomes. However, their association with cardiac mechanics in older persons is unknown. Associations between these biomarkers and cardiac mechanics derived from speckle tracking echocardiography, including left ventricular longitudinal strain (LVLS), early diastolic strain, and left atrial reservoir strain (LARS) were evaluated using standardized beta coefficients () in a cross sectional analysis with cardiac biomarkers in older patients without cardiovascular disease, low ejection fraction, or wall motion abnormalities. Biomarker associations with strain were attenuated by demographics and risk factors. In adjusted models, LVLS was associated with continuous measures of hscTnT (β^∧-0.06, p = 0.020), sST2 (β^∧ -0.05, p = 0.024) and NT-proBNP (β^∧ -0.06, p = 0.007). "High" levels (i.e., greater than prognostic cutpoint) of hscTnT (>13 ng/ml), sST2 (>35 ng/ml), and NT-proBNP (>190 pg/ml) were also associated with worse LVLS. In risk factor adjusted models, LARS was associated with hscTnT (β^∧ -0.08, p = 0.003) and NT-proBNP (β^∧-0.18, p <0.0001). High hscTnT (>13 ng/ml) and high NT-proBNP (>190 pg/ml) were also both associated with worse LARS. Gal-3 was not associated with any strain measure. In conclusion, in persons ≥ 65 years of age, without cardiovascular disease, low ejection fraction, or wall motion abnormalities, hscTnT, sST2, and NT-proBNP are associated with worse LVLS. HscTnT and NT-proBNP are associated with worse LARS. In conclusion, these subclinical increases in blood biomarkers, and their associations with subtle diastolic and systolic dysfunction, may represent pre-clinical heart failure.

Differences in measurement of high-sensitivity troponin in an on-demand and batch-wise setting

BACKGROUND

Most studies assessing the diagnostic value of high-sensitivity troponin in the diagnosis of myocardial infarction used batch-wise analyses of frozen samples for high-sensitivity troponin measurements. Whether the accuracy of these batch-wise high-sensitivity troponin measurements described in diagnostic studies is comparable to clinical routine is unknown.

METHODS

We enrolled 937 patients presenting with suspected myocardial infarction in this prospective cohort study. Measurements of high-sensitivity troponin I (Abbott Architect) and high-sensitivity troponin T (Roche) were performed in two settings: (a) on-demand in clinical routine using fresh blood samples; and (b) in batches using frozen blood samples from the same individuals at three timepoints (0 hours, 1 hour and 3 hours after presentation).

RESULTS

Median troponin levels were not different between on-demand and batch-wise measurements. Troponin levels in the range of 0 to 40 ng/L showed a very high correlation between the on-demand and batch setting (Pearson correlation coefficient (r) was 0.92-0.95 for high-sensitivity troponin I and 0.96 for high-sensitivity troponin T). However, at very low troponin levels (0 to 10 ng/L) correlation between the two settings was moderate (r for high-sensitivity troponin I 0.59-0.66 and 0.65-0.69 for high-sensitivity troponin T). Application of guideline-recommended rapid diagnostic algorithms showed similar diagnostic performance with both methods.

CONCLUSIONS

Overall on-demand and batch-wise measurements of high-sensitivity troponin provided similar results, but their correlation was moderate, when focusing on very low troponin levels. The application of rapid diagnostic algorithms was safe in both settings.Trial Registration: www.clinicaltrials.gov (NCT02355457).

Systemic Cardiac Troponin T Associated With Incident Atrial Fibrillation Among Patients With Suspected Stable Angina Pectoris

Higher concentrations of cardiac troponin T are associated with coronary artery disease (CAD) and adverse cardiovascular prognosis. The relation with incident atrial fibrillation (AF) is less explored. We studied this association among 3,568 patients evaluated with coronary angiography for stable angina pectoris without previous history of AF. The prospective association between high-sensitivity cardiac troponin T (hs-cTnT) categories (≤3 ng/L; n = 1,694, 4-9; n = 1,085, 10 to 19; n = 614 and 20 to 30; n = 175) and incident AF and interactions with the extent of CAD were studied by Kaplan-Meier plots and Cox regression. Risk prediction improvements were assessed by receiver operating characteristic area under the curve (ROC-AUC) analyses. During median (25 to 75 percentile) 7.3 (6.3 to 8.6) years of follow-up 412 (11.5%) were diagnosed with AF. In a Cox model adjusted for age, gender, body mass index, hypertension, diabetes mellitus, smoking, estimated glomerular filtration rate, and left ventricular ejection fraction, hazard ratios (HRs) (95% confidence intervals [CIs]) were 1.53 (1.16 to 2.03), 2.03 (1.49 to 2.78), and 2.15 (1.40 to 3.31) when comparing the second, third, and fourth to the first hs-cTnT group, respectively (P for trend <0.000001). The strongest association between hs-cTnT levels and incident AF was found among patients without obstructive CAD (P_int = 0.024) and adding hs-cTnT to established AF risk factors improved risk classification slightly (ΔROC 0.006, p = 0.044). In conclusion, in patients with suspected stable angina higher levels of hs-cTnT predicted increased risk of incident AF. This was most pronounced in patients without obstructive CAD suggesting an association not mediated by coronary disease.

Levels and Change in Galectin-3 and Association With Cardiovascular Events: The ARIC Study

Background

Circulating galectin‐3 levels provide prognostic information in patients with established heart failure (HF), but the associations between galectin‐3 levels and other incident cardiovascular events in asymptomatic individuals at midlife and when remeasured ≈15 years later are largely uncharacterized.

Methods and Results

Using multivariable Cox proportional hazards models, we identified associations between plasma galectin‐3 levels (hazard ratio [HR] per 1 SD increase in natural log galectin‐3) and incident coronary heart disease, ischemic stroke, HF hospitalization, and total mortality in ARIC (Atherosclerosis Risk in Communities) participants free of cardiovascular disease at ARIC visit 4 (1996–1998; n=9247) and at ARIC visit 5 (2011–2013; n=4829). Higher galectin‐3 level at visit 4 (median age 62) was independently associated with incident coronary heart disease (adjusted HR, 1.30; 95% CI, 1.06–1.60), ischemic stroke (HR, 1.42; 95% CI, 1.01–2.00), HF (HR, 1.44; 95% CI, 1.17–1.76), and mortality (HR, 1.56; 95% CI, 1.35–1.80). At visit 5 (median age, 74), higher galectin‐3 level was associated with incident HF (HR, 1.93; 95% CI, 1.15–3.24) and total mortality (HR, 1.70; 95% CI, 1.15–2.52), but not coronary heart disease or stoke. Individuals with the greatest increase in galectin‐3 levels from visit 4 to visit 5 were also at increased risk of incident HF and total mortality.

Conclusions

In a large, biracial community‐based cohort, galectin‐3 measured at midlife and older age was associated with increased risk of cardiovascular events. An increase in galectin‐3 levels over this period was also associated with increased risk.

Why does Russia have such high cardiovascular mortality rates? Comparisons of blood-based biomarkers with Norway implicate non-ischaemic cardiac damage

Background

Russia has one of the highest rates of mortality from cardiovascular disease (CVD). At age 35–69 years, they are eight times higher than in neighbouring Norway. Comparing profiles of blood-based CVD biomarkers between these two populations can help identify reasons for this substantial difference in risk.

Methods

We compared age-standardised mean levels of CVD biomarkers for men and women aged 40–69 years measured in two cross-sectional population-based studies: Know Your Heart (KYH) (Russia, 2015–2018; n=4046) and the seventh wave of the Tromsø Study (Tromsø 7) (Norway, 2015–2018; n=17 646). A laboratory calibration study was performed to account for inter-laboratory differences.

Results

Levels of total, low-density lipoprotein-, high-density lipoprotein-cholesterol and triglycerides were comparable in KYH and Tromsø 7 studies. N-terminal pro-b-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin T (hs-cTnT) and high-sensitivity C-reactive protein (hsCRP) were higher in KYH compared with Tromsø 7 (NT-proBNP was higher by 54.1% (95% CI 41.5% to 67.8%) in men and by 30.8% (95% CI 22.9% to 39.2%) in women; hs-cTnT—by 42.4% (95% CI 36.1% to 49.0%) in men and by 68.1% (95% CI 62.4% to 73.9%) in women; hsCRP—by 33.3% (95% CI 26.1% to 40.8%) in men and by 35.6% (95% CI 29.0% to 42.6%) in women). Exclusion of participants with pre-existing coronary heart disease (279 men and 282 women) had no substantive effect.

Conclusions

Differences in cholesterol fractions cannot explain the difference in CVD mortality rate between Russia and Norway. A non-ischemic pathway to the cardiac damage reflected by raised NT-proBNP and hs-cTnT is likely to contribute to high CVD mortality in Russia.

Prognostic Value of Serial High-Sensitivity Troponin T Measurements in Adults With Congenital Heart Disease

BACKGROUND

Single high-sensitivity troponin T (hs-TnT) measurement is predictive of cardiac events in adults with congenital heart disease (ACHD). We aimed to study the prognostic value of serial hs-TnT measurements in stable patients with ACHD.

METHODS

In total, 602 consecutive patients with ACHD were enrolled in this prospective study (2011-2013). Blood sampling was performed at enrollment and thereafter yearly during scheduled visits, up to 4 years. Hs-TnT, N-terminal pro B-type natriuretic peptide (NT-proBNP), and estimated glomerular filtration rate (eGFR) were measured. The composite primary endpoint was defined as all-cause mortality, heart failure, arrhythmia, hospitalization, cardiac (re)interventions, or thromboembolic events. The relationship between changes in serial hs-TnT and the primary endpoint was studied by joint models with adjustment for repeated NT-proBNP and eGFR.

RESULTS

In 601 patients (median age, 33 [interquartile range, 25-41] years, 42% women, 90% NYHA I), at least 1 hs-TnT measurement was performed; a mean of 4.3 hs-TnT measurements per patient were collected. After a median follow-up of 5.8 [interquartile range, 5.3-6.3] years, 229 (38.1%) patients reached the primary endpoint. On average, hs-TnT levels increased over time, and more in patients who reached the primary endpoint (P < 0.001). A 2-fold higher hs-TnT was associated with the primary endpoint (unadjusted hazard ratio, 1.62; 95% confidence interval, 1.44-1.82; P < 0.001). The association remained after adjustment for repeated eGFR but not when adjusted for repeated NT-proBNP; repeated NT-proBNP remained associated with the primary endpoint.

CONCLUSION

In stable patients with ACHD, hs-TnT levels increased before the occurrence of an event and repeated hs-TnT was associated with the risk of adverse cardiac events. However, repeated hs-TnT was not superior to repeated NT-proBNP.

Biological variation of cardiac troponins in chronic kidney disease

Background

Patients with chronic kidney disease often have increased plasma cardiac troponin concentration in the absence of myocardial infarction. Incidence of myocardial infarction is high in this population, and diagnosis, particularly of non ST-segment elevation myocardial infarction (NSTEMI), is challenging. Knowledge of biological variation aids understanding of serial cardiac troponin measurements and could improve interpretation in clinical practice. The National Academy of Clinical Biochemistry (NACB) recommended the use of a 20% reference change value in patients with kidney failure. The aim of this study was to calculate the biological variation of cardiac troponin I and cardiac troponin T in patients with moderate chronic kidney disease (glomerular filtration rate [GFR] 30–59 mL/min/1.73 m2).

Methods and results

Plasma samples were obtained from 20 patients (median GFR 43.0 mL/min/1.73 m2) once a week for four consecutive weeks. Cardiac troponin I (Abbott ARCHITECT® i2000SR, median 4.3 ng/L, upper 99th percentile of reference population 26.2 ng/L) and cardiac troponin T (Roche Cobas® e601, median 11.8 ng/L, upper 99th percentile of reference population 14 ng/L) were measured in duplicate using high-sensitivity assays. After outlier removal and log transformation, 18 patients’ data were subject to ANOVA, and within-subject (CVI), between-subject (CVG) and analytical (CVA) variation calculated. Variation for cardiac troponin I was 15.0%, 105.6%, 8.3%, respectively, and for cardiac troponin T 7.4%, 78.4%, 3.1%, respectively. Reference change values for increasing and decreasing troponin concentrations were +60%/–38% for cardiac troponin I and +25%/–20% for cardiac troponin T.

Conclusions

The observed reference change value for cardiac troponin T is broadly compatible with the NACB recommendation, but for cardiac troponin I, larger changes are required to define significant change. The incorporation of separate RCVs for cardiac troponin I and cardiac troponin T, and separate RCVs for rising and falling concentrations of cardiac troponin, should be considered when developing guidance for interpretation of sequential cardiac troponin measurements.

Usefulness of a Point-of-Care Analyzer to Measure Cardiac Troponin I and D-Dimer Concentrations in Critically Ill Horses With Gastrointestinal Diseases

Point-of-care (POC) systems for the joint measurement of Troponin and D-dimers have not been studied in horses. The aim of this study was to perform the validation of a POC system (AQT90 FLEX) for the measurement of cardiac troponin I (cTnI) and D-dimers in the serum of horses with gastrointestinal diseases. The main objective was to evaluate whether or not this system can distinguish healthy animals from diseased animals. A sample of 33 horses was included in the study: control group (n = 10) and horses with gastrointestinal disorders (n = 21), which were classified according to their outcome in survivors (subgroup A = 9) and nonsurvivors (subgroup B = 12). Considering the diagnosis of the process, ill horses were classified into three groups: inflammatory (I = 7), obstructive (O = 9), and strangulating diseases (S = 5). The clinical usefulness of AQT90 FLEX was validated by the study of linearity, coefficient of variation, and detection limits. Later, concentrations of D-dimers and cTnI were measured. A significant increase in both parameters was detected in ill animals (cTnI: control: 0.014 ± 0.01 μg/mL, survivors: 0.27 ± 0.37 μg/mL, nonsurvivors: 0.60 ± 1.21 μg/mL; D-dimers: control: 104.90 ± 30.82 ng/mL, survivors: 1,217.22 ± 1,213.28 ng/mL, nonsurvivors: 1,613.67 ± 1,426.75 ng/mL), although there were no statistically significant differences in concentrations according to diagnosis and outcome. In conclusion, AQT90 FLEX POC analyzer can be used in horses with gastrointestinal diseases to measure cTnI and D-dimer concentrations. It is a quick, practical, and minimally invasive tool that helps in determining the severity of illness.

Evidence for a Direct Harmful Effect of Alcohol on Myocardial Health: A Large Cross-Sectional Study of Consumption Patterns and Cardiovascular Disease Risk Biomarkers From Northwest Russia, 2015 to 2017

Background Alcohol drinking is an increasingly recognized risk factor for cardiovascular disease. However, there are few studies of the impact of harmful and hazardous drinking on biomarkers of myocardial health. We conducted a study in Russia to investigate the impact of heavy drinking on biomarkers of cardiac damage and inflammation. Methods and Results The Know Your Heart study recruited a random sample of 2479 participants from the population of northwest Russia (general population) plus 278 patients (narcology clinic subsample) with alcohol problems. The general population sample was categorized into harmful drinkers, hazardous drinkers, nonproblem drinkers, and nondrinkers, according to self-reported level of alcohol consumption, whereas the narcology clinic sample was treated as the separate group in the analysis. Measurements were made of the following: (1) high-sensitivity cardiac troponin T, (2) NT-proBNP (N-terminal pro-B-type natriuretic peptide), and (3) hsCRP (high-sensitivity C-reactive protein). The narcology clinic subsample had the most extreme drinking pattern and the highest levels of all 3 biomarkers relative to nonproblem drinkers in the general population: high-sensitivity cardiac troponin T was elevated by 10.3% (95% CI, 3.7%-17.4%), NT-proBNP by 46.7% (95% CI, 26.8%-69.8%), and hsCRP by 69.2% (95% CI, 43%-100%). In the general population sample, NT-proBNP was 31.5% (95% CI, 3.4%-67.2%) higher among harmful drinkers compared with nonproblem drinkers. Overall, NT-proBNP and hsCRP increased with increasing intensity of alcohol exposure (test of trend P<0.001). Conclusions These results support the hypothesis that heavy alcohol drinking has an adverse effect on cardiac structure and function that may not be driven by atherosclerosis.

Longitudinal Change in Galectin-3 and Incident Cardiovascular Outcomes

BACKGROUND

Galectin-3 (Gal-3) has been associated with heart failure (HF) and poor cardiovascular outcomes. However, the effect of longitudinal changes in Gal-3 on clinical outcomes remains unclear.

OBJECTIVES

The authors sought to study clinical determinants of change in Gal-3 among community-dwelling individuals. Further, they sought to examine the role of serial Gal-3 measurements in predicting risk of future HF, cardiovascular disease (CVD), and mortality.

METHODS

A total of 2,477 participants in the Framingham Heart Study Offspring cohort underwent measurement of plasma Gal-3 levels at 2 examinations (1995 to 1998 and 2005 to 2008). Linear regression models were used to examine clinical correlates of change in Gal-3. Proportional hazards models were used to relate future clinical outcomes with change in Gal-3.

RESULTS

The following clinical correlates were associated with greater longitudinal increases in Gal-3 levels: age, female sex, hypertension, diabetes, body mass index, interim development of chronic kidney disease, and HF (p < 0.0001 for all in multivariable model). Change in Gal-3 was associated with future HF (hazard ratio [HR]: 1.39 per 1-SD increase; 95% confidence interval [CI]: 1.13 to 1.71), CVD (HR: 1.29; 95% CI: 1.11 to 1.51), and all-cause mortality (HR: 1.30; 95% CI: 1.17 to 1.46). Change in Gal-3 was associated with both HF with preserved as well as reduced ejection fraction (p < 0.05 for both).

CONCLUSIONS

Longitudinal changes in Gal-3 are associated with traditional cardiovascular risk factors and renal disease. In turn, change in Gal-3 predicts future HF, CVD, and mortality in the community. Future studies are needed to determine whether serial Gal-3 measures may be useful in disease prevention.

Repeat Measurements of High Sensitivity Troponins for the Prediction of Recurrent Cardiovascular Events in Patients With Established Coronary Heart Disease: An Analysis From the KAROLA Study

Background

High‐sensitivity cardiac troponins T and I (hs‐cTnT and hs‐cTnI) are established biomarkers for myocardial injury and used for diagnostic and prognostic purposes. However, whether repeat measurements improve prediction of recurrent cardiovascular disease (CVD) events in patients with stable coronary heart disease (CHD) after adjustment for several other novel biomarkers remains unclear.

Methods and Results

We measured both troponins in 873 coronary heart disease patients from the KAROLA (Langzeiterfolge der Kardiologischen Anschlussheilbehandlung) study about 9 weeks after their initial acute event (baseline) and after 12 months, followed them for 12 years, assessed a combined CVD end point, and adjusted for several risk factors. As we found evidence for effect modification, results were stratified according to presence of myocardial infarction at baseline. During follow‐up, 186 fatal and non‐fatal CVD events occurred. Both baseline and 12‐months troponin concentrations were significantly associated with CVD events in patients without myocardial infarction at baseline; in tendency 12 months of troponin showed stronger hazard ratios (hs‐cTnT: hazard ratios 1.91 (95% CI 1.17–3.11) versus baseline values 1.71 (95% CI 1.08–2.70) and for hs‐cTnI: hazard ratio 1.55 (95% CI 1.05–2.30) versus baseline value 1.22 (95% CI 0.88–1.68) in the fully and simultaneously adjusted model.

Conclusions

Both troponins are consistently associated with recurrent cardiovascular events after adjustment for emerging risk factors during follow‐up in our study especially evident in patients without myocardial infarction at baseline. Troponin values at 12 months of follow‐up showed independent associations with future CVD events in addition to baseline assessments of troponins.

Identification of acute myocardial infarction in elderly patients using optimized highly sensitive troponin I thresholds

Purpose: Established diagnostic thresholds for high-sensitivity cardiac troponins (hs-cTn) might not apply for elderly patients as they are elevated irrespective of the presence of an acute myocardial infarction (AMI). Aim of the present study was to investigate hs-cTnI in elderly patients with suspected AMI and to calculate optimized diagnostic cutoffs. Material and methods: Data from a prospective multi-centre study and from a second independent prospective single-centre cohort study were analysed. A number of 2903 patients were eligible for further analysis. Patients > 70 years were classified as elderly. hs-cTnI was measured upon admission. Results: Around 34.7% of 2903 patients were classified as elderly. Around 22.5% of elderly patients were finally diagnosed with AMI. Elderly patients had higher hs-cTnI levels at admission irrespective of the final diagnosis (p < 0.001). According to the AUROC, hs-cTnI was a strong marker for detection of AMI in elderly patients. Application of the 99th percentile cutoffs showed a substantially lower specificity in elderly. By using optimized thresholds, specificity was improved to levels as in younger patients in both cohorts but accompanied with a decrease in sensitivity. Conclusions: hs-cTnI levels have a lower specificity for detecting AMI in elderly patients. This lower specificity can be improved by using hs-cTnI thresholds optimized for elderly patients.

Ameliorative effect of Rutin on sodium fluoride-induced hypertension through modulation of Kim-1/NF-κB/Nrf2 signaling pathway in rats

Sodium fluoride is one of the neglected environmental contaminants. Inorganic fluorides in the environment are found in the air, water, and land. In the study, forty-male Wistar albino rats were randomly divided into four groups with 10 rats in a group. Group A was the control group which was given normal saline, Group B was exposed to 300 ppm of NaF in drinking water, while Groups C and D received NaF along Rutin (100 mg/kg and 200 mg/kg) orally daily for a week. Administration of NaF alone led to significant increases in blood pressure, and deceased serum nitric oxide. Immunohistochemistry revealed higher expressions of kidney injury molecule I (Kim-1), nuclear factor kappa beta (NF-κB), and down regulation of nuclear factor erythroid 2-related factor 2 (Nrf2) in rats administered NaF. Rutin co-treatment with NaF normalized blood pressure, lowered Kim-1 and NF-κB expressions, and improved nitric oxide bioavailability.

Luteolin-mediated Kim-1/NF-kB/Nrf2 signaling pathways protects sodium fluoride-induced hypertension and cardiovascular complications

The use of sodium fluoride (NaF) as a major ingredient for tooth paste, mouth wash, and mouth rinse has become inevitable in our day-to-day life. However, flavonoids such as Luteolin might be of great value in the prevention of toxicity associated with accidental or inevitable ingestion of NaF. In the study, 40 male Wistar albino rats were randomly divided into four groups with 10 rats in a group. Group A was the control group and received normal saline, Group B was exposed to NaF at 300 ppm (300 mg/L) in drinking water daily for a week, Groups C and D were exposed to 300 ppm (300 mg/L) of NaF and coadministered with Luteolin orally daily at a dosage of 100 mg/kg and 200 mg/kg for the same time point. Our results indicated that NaF caused significant increases in systolic blood pressure, diastolic blood pressure, mean arterial pressure, malondialdehyde, protein carbonyl, myeloperoxidase, advanced oxidative protein products, together with significant reductions in glutathione peroxidase, superoxide dismutase, catalase, glutathione reductase, reduced glutathione, and nitric oxide (NO) bioavailability. The electrocardiogram results showed that NaF alone caused significant prolongation of QT and QTc intervals. Immunohistochemistry revealed that NaF caused increase expressions of Kidney injury marker 1 (Kim-1), nuclear factor kappa bet (NF-κB), nuclear factor erythroid 2-related factors 2 (Nrf2), and cardiac troponin I (CTnI). Together, Luteolin coadministration with NaF improved NO bioavailability, reduced high blood pressure, markers of oxidative stress, reversed prolongation of QT and QTc intervals, and lowered the expressions of Kim-1, NF-κB, and CTnI. © 2018 BioFactors, 44(6):518-531, 2018.

Analytical Concordance of Diverse Point-of-Care and Central Laboratory Troponin I Assays

BACKGROUND

Cardiac troponin I (cTnI) 99th percentile cutoffs, used in the diagnosis of acute myocardial infarction, are not standardized across cTnI assays. We compared 3 point-of-care (POC) and 1 central laboratory contemporary cTnI assays against the Abbott high-sensitivity (hs) cTnI to evaluate the analytical concordance and the feasibility of using a single cutoff value for all assays.

METHODS

Fresh blood samples collected from 102 inpatients in the coronary care unit were measured on central laboratory instruments (Beckman Coulter DxI AccuTnI+3 TnI, Abbott Architect hs-TnI) and cTnI POC analyzers (Alere Triage Troponin I, Radiometer AQT90, Abbott i-STAT). Agreement and correlation between the contemporary cTnI assays and hs-cTnI assay were assessed using regression analysis. Proportional bias was assessed using Bland-Altman plots. Concordance between the contemporary cTnI and hs-cTnI assays was determined by diagnostic contingency tables at specific cutoffs.

RESULTS

Most POC cTnI assays had excellent correlation with the Abbott hs-cTnI method (r ² = 0.955-0.970) except for Alere Triage (r ² = 0.617), while proportional bias is evident between all cTnI assays. Overall concordance between POC contemporary cTnI assays and hs-cTnI assay was 80% to 90% at their respective 99th percentile cutoffs. The concordance increased to 90% to 95% when a fixed cutoff of 0.03 to 0.05 ng/mL was used across the assays.

CONCLUSIONS

This study demonstrates poor analytical concordance between cTnI assays at the 99th percentile and supports the notion of a single clinical decision limit for cTnI and consequently standardization of diagnostic protocols despite the analytical differences among these assays.

Exploring collagen remodeling and regulation as prognosis biomarkers in stable heart failure

We assessed the predictive ability of circulating biomarkers involved in collagen synthesis (procollagen type I N-terminal propeptide [PINP], and procollagen type III N-terminal propeptide [PIIINP], collagen degradation (c-terminal telopeptide of collagen type I [CTx] and mediators of cardiac fibrosis (Galectin-3 and soluble suppression of tumorigenicity 2 protein or sST2) as prognosis markers in 182 subjects with chronic heart failure (HF). In univariate analysis, all markers predicted mortality (except for PINP). A multivariate baseline model was fitted including variables potentially associated with mortality in HF patients. The baseline regression model included age, clinical data and biomarkers. We created four models from the baseline model augmented with the levels of hs-cTnT, CRP and NT-proBNP (model 1), CTx/PIIINP ratio, sST2 and Galectine-3 (model 2), NT-proBNP and sST2 (model 3) and NT-proBNP, CTx/PIIINP ratio and sST2 (model 4), to test whether these biomarkers have an incremental value for predicting mortality. After the addition of all biomarkers to the baseline model, age, CTx/PIIINP ratio and sST2 remained significant predictors. By contrast, Galectin-3 was not significantly associated with mortality. A multimarker strategy, demonstrated that the greatest prognostic improvement was attained with the combined addition of CTx/PIIINP ratio and sST2 highlighting the potential role of fibrosis pathways in risk stratification.

5th generation cardiac troponin I and T assays in clinical routine - A head-to-head comparison with data from the Linz troponin (LITROP) study

BACKGROUND

In Europe, clinicians use so called high-sensitivity assays for the measurement of cardiac troponin I and T (i.e., hs-cTnI and hs-cTnT assays, also termed 5th generation assays) since several years. We aimed at performing a head-to-head comparison of two 5th generation assays in "real life use".

METHODS

We studied 3588 consecutive patients presenting to an emergency department. We used both, a hs-cTnI assay from Abbott and a hs-cTnT assay from Roche in clinical routine. We assessed (1) the capabilities of hs-cTnI and hs-cTnT for the prediction of 3.7 year all-cause mortality; (2) discordant diagnoses of myocardial injury by hs-cTnI and hs-cTnT according to the European gender-neutral 99th percentile upper reference limits (i.e., 26 ng/L and 14 ng/L, respectively); and (3) analyte kinetics in patient with serial troponin measurements.

RESULTS

With respect to prognosis of all-cause mortality, the AUC of hs-cTnI was 0.81 (95% CI, 0.80-0.82), and the AUC of hs-cTnT was 0.85 (95% CI, 0.84-0.86). With respect to discordant diagnoses, 21% of the 3588 patients were classified as having myocardial injury by hs-cTnT but not by hs-cTnI, and < 1% were classified as having myocardial injury by hs-cTnI but not by hs-cTnT. In the patients with serial blood sampling, the median delta values were 6.3 ng/L and 25% for hs-cTnI, and 4.2 ng/L and 16% for hs-cTnT.

CONCLUSION

We found different characteristics of the Abbott hs-cTnI and the Roche hs-cTnT assays, especially when using the European gender-neutral 99th percentile upper reference limits. Clinically, these different characteristics are related to discordant results in the diagnosis and prognosis of patients presenting to an emergency department.

Detectable High-Sensitivity Cardiac Troponin within the Population Reference Interval Conveys High 5-Year Cardiovascular Risk: An Observational Study

BACKGROUND

Increased cardiac troponin I or T detected by high-sensitivity assays (hs-cTnI or hs-cTnT) confers an increased risk of adverse prognosis. We determined whether patients presenting with putatively normal, detectable cTn concentrations [> limit of detection and < upper reference limit (URL)] have increased risk of major adverse cardiovascular events (MACE) or all-cause mortality.

METHODS

A prospective 5-year follow-up of patients recruited in the emergency department with possible acute coronary syndrome (ACS) and cTn concentrations measured with hs-cTnI (Abbott) and hs-cTnT (Roche) assays. Cox regression models were generated with adjustment for covariates in those without MACE on presentation. Hazard ratios (HRs) for hs-cTn were calculated relative to the HRs at the median concentration.

RESULTS

Of 1113 patients, 836 were without presentation MACE. Of these, 138 incurred a MACE and 169 died during a median 5.8-year follow-up. HRs for MACE at the URLs were 2.3 (95% CI, 1.7-3.2) for hs-cTnI and 1.8 (95% CI, 1.3-2.4) for hs-cTnT. Corresponding HRs for mortality were 1.7 (95% CI, 1.2-2.2) for hs-cTnI and 2.3 (95 % CI, 1.7-3.1) for hs-cTnT. The HR for MACE increased with increasing hs-cTn concentration similarly for both assays, but the HR for mortality increased at approximately twice the rate for hs-cTnT than hs-cTnI. Patients with hs-cTnI ≥10 ng/L or hs-cTnT ≥16 ng/L had the same percentage of MACE at 5-year follow-up (33%) as patients with presentation MACE.

CONCLUSIONS

Many patients with ACS ruled out and putatively normal but detectable hs-cTnI concentrations are at similar long-term risk as those with MACE. hs-cTnT concentrations are more strongly associated with 5-year mortality than hs-cTnI.