Estimation of numbers of mature and immature neutrophils in blood by a novel, rapid and simple technology.

Counting numbers of blood neutrophils is one of the most common laboratory tests in modern clinical medicine. In this report, we have tested the idea that immunoassay of major constituents of mature neutrophils might serve as proxy of cell counting and allow the development of rapid and simple point-of-care tests. The procedure may also allow for the estimate of the state of maturity of the circulating blood cells. Immunoassays for myeloperoxidase (MPO) and lactoferrin (LF) were used to measure the respective protein in whole blood extracts of 275 unselected hospitalized patient and in 51 healthy controls and leukemia patients of which eight were followed before, during and after remission treatment. MPO was correlated to neutrophil counts in the unselected hospitalized population (r = 0.95, p <.0001). Huge variations were seen in whole blood extracts of patients with AML with very high MPO/LF ratios in half of the AML patients and in all three patients with APL. In extracts from patients with ALL no difference was found in the ratio as compared to healthy persons. The monitoring of AML patients during remission treatment showed intriguing patterns one of which suggested the possibility to monitor the myelopoietic activity in the bone marrow during the recovery phase. We show a novel and easy technology to count mature neutrophils in blood and also to monitor myeloid cell maturity in the blood as well as myelopoietic activity in the bone marrow. The technology lends itself to the development of a rapid and simple point-of-care test.

Blood eosinophil count and airway epithelial transcriptome relationships in COPD versus asthma.

BACKGROUND: Whether the clinical or pathophysiologic significance of the "treatable trait" high blood eosinophil count in COPD is the same as for asthma remains controversial. We sought to determine the relationship between the blood eosinophil count, clinical characteristics and gene expression from bronchial brushings in COPD and asthma. METHODS: Subjects were recruited into a COPD (emphysema versus airway disease [EvA]) or asthma cohort (Unbiased BIOmarkers in PREDiction of respiratory disease outcomes, U-BIOPRED). We determined gene expression using RNAseq in EvA (n = 283) and Affymetrix microarrays in U-BIOPRED (n = 85). We ran linear regression analysis of the bronchial brushings transcriptional signal versus blood eosinophil counts as well as differential expression using a blood eosinophil > 200 cells/µL as a cut-off. The false discovery rate was controlled at 1% (with continuous values) and 5% (with dichotomized values). RESULTS: There were no differences in age, gender, lung function, exercise capacity and quantitative computed tomography between eosinophilic versus noneosinophilic COPD cases. Total serum IgE was increased in eosinophilic asthma and COPD. In EvA, there were 12 genes with a statistically significant positive association with the linear blood eosinophil count, whereas in U-BIOPRED, 1197 genes showed significant associations (266 positive and 931 negative). The transcriptome showed little overlap between genes and pathways associated with blood eosinophil counts in asthma versus COPD. Only CST1 was common to eosinophilic asthma and COPD and was replicated in independent cohorts. CONCLUSION: Despite shared "treatable traits" between asthma and COPD, the molecular mechanisms underlying these clinical entities are predominately different.

Fixed airflow obstruction relates to eosinophil activation in asthmatics.

BACKGROUND: Some asthmatics develop irreversible chronic airflow obstruction, for example, fixed airflow obstruction (fixed-AO). This is probably a consequence of airway remodelling, but neither its relation to inflammation nor which asthma biomarkers can be clinically useful are elucidated. We hypothesized that the presence of type 2 inflammation relates to fixed-AO. OBJECTIVES: To evaluate the presence of four markers for type 2 inflammation in fixed airflow obstruction among asthmatics. METHODS: This was a cross-sectional study of 403 participants with asthma, aged 17-75 years, from three Swedish centres. Fixed airflow obstruction was defined as forced expiratory volume during the first second (FEV1 ) over forced vital capacity (FVC) being below the lower limit of normal (LLN). The following type 2 inflammation markers were assessed: exhaled nitric oxide (FeNO), serum periostin, serum eosinophil cationic protein (S-ECP), and urinary eosinophil-derived neurotoxin (U-EDN). RESULTS: Elevated U-EDN (values in the highest tertile, ≥65.95 mg/mol creatinine) was more common in subjects with fixed-AO vs. subjects without fixed-AO: 55% vs. 29%, P < 0.001. Elevated U-EDN related to increased likelihood of having fixed-AO in both all subjects and never-smoking subjects, with adjusted (adjusted for sex, age group, use of inhaled corticosteroids last week, atopy, early-onset asthma, smoking history, and packyears) odds ratios (aOR) of 2.38 (1.28-4.41) and 2.51 (1.04-6.07), respectively. In a separate analysis, having both elevated S-ECP (>20 µg/L) and U-EDN was related to having the highest likelihood of fixed-AO (aOR (95% CI) 6.06 (2.32-15.75)). Elevated serum periostin or FeNO did not relate to fixed-AO. CONCLUSIONS AND CLINICAL RELEVANCE: These findings support that type 2 inflammation, and in particular eosinophil inflammation, is found in asthma with fixed-AO. This could indicate a benefit from eosinophil-directed therapies. Further longitudinal studies are warranted to investigate causality and relation to lung function decline.

Early invasive versus non-invasive treatment in patients with non-ST-elevation acute coronary syndrome (FRISC-II): 15 year follow-up of a prospective, randomised, multicentre study.

BACKGROUND: The FRISC-II trial was the first randomised trial to show a reduction in death or myocardial infarction with an early invasive versus a non-invasive treatment strategy in patients with non-ST-elevation acute coronary syndrome. Here we provide a remaining lifetime perspective on the effects on all cardiovascular events during 15 years' follow-up. METHODS: The FRISC-II prospective, randomised, multicentre trial was done at 58 Scandinavian centres in Sweden, Denmark, and Norway. Between June 17, 1996, and Aug 28, 1998, we randomly assigned (1:1) 2457 patients with non-ST-elevation acute coronary syndrome to an early invasive treatment strategy, aiming for revascularisation within 7 days, or a non-invasive strategy, with invasive procedures at recurrent symptoms or severe exercise-induced ischaemia. Plasma for biomarker analyses was obtained at randomisation. For long-term outcomes, we linked data with national health-care registers. The primary endpoint was a composite of death or myocardial infarction. Outcomes were compared as the average postponement of the next event, including recurrent events, calculated as the area between mean cumulative count-of-events curves. Analyses were done by intention to treat. FINDINGS: At a minimum of 15 years' follow-up on Dec 31, 2014, data for survival status and death were available for 2421 (99%) of the initially recruited 2457 patients, and for other events after 2 years for 2182 (89%) patients. During follow-up, the invasive strategy postponed death or next myocardial infarction by a mean of 549 days (95% CI 204-888; p=0·0020) compared with the non-invasive strategy. This effect was larger in non-smokers (mean gain 809 days, 95% CI 402-1175; pinteraction=0·0182), patients with elevated troponin T (778 days, 357-1165; pinteraction=0·0241), and patients with high concentrations of growth differentiation factor-15 (1356 days, 507-1650; pinteraction=0·0210). The difference was mainly driven by postponement of new myocardial infarction, whereas the early difference in mortality alone was not sustained over time. The invasive strategy led to a mean of 1128 days (95% CI 830-1366) postponement of death or next readmission to hospital for ischaemic heart disease, which was consistent in all subgroups (p<0·0001). INTERPRETATION: During 15 years of follow-up, an early invasive treatment strategy postponed the occurrence of death or next myocardial infarction by an average of 18 months, and the next readmission to hospital for ischaemic heart disease by 37 months, compared with a non-invasive strategy in patients with non-ST-elevation acute coronary syndrome. This remaining lifetime perspective supports that an early invasive treatment strategy should be the preferred option in most patients with non-ST-elevation acute coronary syndrome. FUNDING: Swedish Heart-Lung Foundation, Swedish Foundation for Strategic Research, and Uppsala Clinical Research Center.

High-Sensitivity Cardiac Troponin I Is a Strong Predictor of Cardiovascular Events and Mortality in the AGES-Reykjavik Community-Based Cohort of Older Individuals.

BACKGROUND: The objective of this study was to investigate the predictive power of a high-sensitivity cardiac troponin I (hs-cTnI) assay for cardiovascular events and mortality in a large population of older community dwellers. METHODS: Blood was collected from 5764 individuals (age 66-98 years) during the period of 2002-2006 and the outcome as to all-cause death and incidence of cardiovascular disease (CVD) and coronary heart disease (CHD) followed up to 10 years. hs-cTnI (Abbott) was measured in serum to assess the association of this marker with CVD, CHD and death, and finally, to compare the results with conventional risk factors by multivariable statistical analysis. RESULTS: The median (interquartile range) concentrations of hs-cTnI were 8.4 ng/L (5.6-14.2 ng/L) and 5.3 ng/L (3.8-8.1 ng/L) in men (2416) and women (3275), respectively, and the concentrations increased linearly with age. Outcomes as to all-cause death and incidence of CVD and CHD were significantly associated with increasing concentrations of hs-cTnI beginning well below the 99th percentile concentrations. The associations with outcome remained after adjustments for conventional risk factors and were similar in men and women. CONCLUSIONS: Our findings suggest that hs-cTnI reflects the status of the myocardium even in seemingly healthy individuals and that the measurements of hs-cTnI may be useful for primary prediction of heart disease; this should form the basis for future prospective clinical trials for determining whether measuring hs-cTnI can be used in the prevention of CVD/CHD.

Evaluation of Temporal Changes in Cardiovascular Biomarker Concentrations Improves Risk Prediction in an Elderly Population from the Community.

BACKGROUND: There is increasing interest in measurements of cardiovascular (CV) biomarker concentrations for risk prediction in the general population. We investigated the prognostic utility of a panel of novel CV biomarkers including biomarker changes over time. METHODS: We measured concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP), midregional proadrenomedullin, high-sensitivity cardiac troponin I, growth-differentiation factor-15 (GDF-15), soluble ST2 (sST2), and galectin-3 at baseline and 5 years later in 1016 elderly individuals participating in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Assessed outcomes included all-cause mortality and fatal and nonfatal CV events (in participants without CV disease at baseline) during 10 years of follow-up. RESULTS: GDF-15 exhibited the strongest association with all-cause mortality (n = 158) with a hazard ratio (HR) per 1-SD increase in standardized ln GDF-15 of 1.68 (95% CI, 1.44-1.96). NT-proBNP was the only biomarker to predict CV events (n = 163; HR 1.54 [95% CI, 1.30-1.84]). GDF-15 and NT-proBNP also improved metrics of discrimination and reclassification of the respective outcomes. Changes in GDF-15 concentrations between 70 and 75 years predicted all-cause mortality whereas changes in NT-proBNP predicted both outcomes. The other biomarkers and their temporal changes provided only moderate prognostic value apart from sST2 which had a neutral relationship with adverse events. CONCLUSIONS: Evaluation of temporal changes in GDF-15 and NT-proBNP concentrations improves risk prediction in an elderly population. These findings are of considerable interest given the emphasis on biomarkers as tools to identify and monitor at-risk individuals with preclinical and potentially modifiable stages of CV disease.

Relation between cardiovascular disease risk markers and brain infarcts detected by magnetic resonance imaging in an elderly population.

BACKGROUND: Established cardiovascular risk markers, such as hypertension, are associated with increased risk of brain infarcts. The newer markers N-terminal pro-brain natriuretic peptide, troponin I, C-reactive protein, and cystatin C may affect the risk of cardiovascular events and potentially, thereby, also stroke. We investigated the association between established and new risk markers for cardiovascular disease and brain infarcts detected by magnetic resonance imaging (MRI) at age 75. METHODS: Four hundred six randomly selected subjects from the Prospective Investigation of the Vasculature in Uppsala Seniors study were examined with MRI of the brain at age 75. Blood samples, measurements, and dedicated questionnaires at age 70 were used for analysis of risk markers. A history of diseases had been obtained at age 70 and 75. MRI was evaluated regarding lacunar and cortical infarcts. Univariate associations between outcomes and risk markers were assessed with logistic regression models. RESULTS: One or more infarcts were seen in 23% of the subjects (20% had only lacunar infarcts, 1% had only cortical infarcts, and 2% had both). Hypertension (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.4, 4.7) and obesity (OR 1.3; CI 1.0, 1.8) were significantly associated with increased risk of brain infarction. The newer risk markers were not significantly associated with the brain infarcts. CONCLUSIONS: The new markers were not associated with the predominantly lacunar infarcts in our 75-year-old population, why troponin I and NT-proBNP may be associated mainly with cardioembolic infarcts as shown recently.

Cardiac troponin I levels in patients with non-ST-elevation acute coronary syndrome-the importance of gender.

BACKGROUND: Measurement of high-sensitivity cardiac troponin levels is increasingly used in non-ST-elevation acute coronary syndrome (NSTE-ACS). However, studies investigating the distribution and prognostic implications of high-sensitivity troponin levels in men and women separately are currently lacking. METHODS: Cardiac troponin I (cTnI) levels were determined using a high-sensitivity assay (Abbott Laboratories, Abbott Park, IL) in 1,677 male and 1,073 female NSTE-ACS patients participating in the GUSTO IV study. The prognostic associations of cTnI to outcome (30-day composite end point of recurrent myocardial infarction and 1-year mortality) were assessed in multivariable models, using cTnI both as a continuous variable and dichotomized at different sets of single and gender-specific 99th percentiles. RESULTS: Median cTnI levels were 947 and 175 ng/L in men and women, respectively (P < .001). The adjusted odds ratios for cTnI (ln) were similar in men and women. The adjusted odds ratios for cTnI above the tested 99th percentiles levels in contrast were twice as high in women compared with men. This was a consequence of differences in the cTnI distribution and risk gradients across cTnI levels, in particular due to lower event rates in women without cTnI elevation. Gender-specific cutoffs did not improve risk prediction. CONCLUSIONS: Despite overall lower levels, cTnI above the tested 99th percentiles exhibited stronger prognostic information in women with NSTE-ACS compared with men. This likely reflects differences in the pathophysiology and the clinical presentation in NSTE-ACS. Our data, thus, emphasize that women with symptoms of unstable coronary artery disease encompass a broader risk panorama than men.

Cardiac troponin I associated with the development of unrecognized myocardial infarctions detected with MRI.

BACKGROUND: Late enhancement MRI (LE-MRI) and cardiac troponin I (cTnI) are sensitive methods to detect subclinical myocardial injury. We sought to investigate the relation between plasma concentrations of cTnI measured with a high-sensitivity assay (hs-cTnI) and the development of unrecognized myocardial infarctions (UMIs) detected with LE-MRI. METHODS: After approval from the ethics committee and written informed consent were obtained, LE-MRI was performed on 248 randomly selected community-living 70-year-old volunteers and hs-cTnI was determined with a highly sensitive premarket assay. Five years later these individuals were invited to a second LE-MRI, and 176 of them (82 women, 94 men), who did not have a hospital diagnosis of MI, constitute the present study population. LE-MR images were analyzed by 2 radiologists independently and in a consensus reading, blinded to any information on previous disease or assessments. RESULTS: New or larger UMIs were detected in 37 participants during follow-up. Plasma concentrations of hs-cTnI at 70 years of age, which were mainly within what is considered to be the reference interval, were related to new or larger UMIs at 75 years of age with an odds ratio of 1.98 per 1 unit increase in ln-transformed cTnI (95% CI, 1.17-3.35; P = 0.010). Plasma concentrations of hs-cTnI at 70 years of age were associated with the volumes of the UMIs detected at 75 years of age (P = 0.028). CONCLUSIONS: hs-cTnI in 70-year-old community-living women and men was associated with the development of MRI-detected UMIs within 5 years.

Novel sensitive cardiac troponin I immunoassay free from troponin I-specific autoantibody interference.

BACKGROUND: Cardiac troponins (cTnI and cTnT) are the recommended biomarkers of myocardial infarction. As cTn-specific autoantibodies (cTnAAb) can interfere with the cTn detection by state-of-the-art cTnI assays, our objective was to develop a sensitive cTnI immunoassay free from this analytical interference. METHODS: The assay used antibody-coated spots containing three capture Mabs/Fabs directed against the N-terminus, midfragment and C-terminus of cTnI and a europium chelate-labeled tracer Mab against the C-terminus. Following a 3-h sample incubation and washing, cTnI was quantified by time-resolved fluorometry. RESULTS: The limit of detection (LoD) was 2.9 ng/L and the assay was linear up to 50,000 ng/L. The total precision of 10% CV was not reached, but 20% CV was reached at 10 ng/L. Mean cTnI (10-50,000 ng/L) recoveries were 100% and 119% in three cTnAAb-positive and two cTnAAb-negative individuals, respectively, verifying the interference resistance of the antibody design used. On average, Architect hs-cTnI assay gave seven-fold higher cTnI concentrations than the new assay but the correlation between the assays was good (r=0.958). Of apparently healthy individuals (n=159), 18% had measurable cTnI values (>LoD) and 10% were cTnAAb-positive. The proportion of measurable cTnI values, however, was significantly higher in cTnAAb-positive individuals (13/16, median cTnI 8.5 ng/L) than in cTnAAb-negative individuals (15/143, median cTnI

The Human Phospholipase B-II Precursor (HPLBII-P) in Urine as a Novel Biomarker of Increased Glomerular Production or Permeability in Diabetes Mellitus?

Background: A previous report showed that the urine output of HPLBII-P in patients with diabetes mellitus and SARS-CoV-2 infection was increased as a sign of glomerular dysfunction. The aim of this report was to investigate the relation of the urine output of HPLBII-P to diabetes mellitus in two large community-based elderly populations, i.e., the ULSAM and PIVUS cohorts. Methods: HPLBII-P was measured by an ELISA in the urine of a community-based cohort of 839 men (ULSAM) collected at 77 years of age and in the urine of a community-based cohort of 75-year-old men, n = 387, and women, n = 401 (PIVUS). KIM-1, NGAL, and albumin were measured in urine and cathepsin S and cystatin C in serum. Results: HPLBII-P was significantly raised among males with diabetes in the ULSAM (p < 0.0001) and PIVUS cohorts (p ≤ 0.02), but not in the female cohort of PIVUS. In the female subpopulation of insulin-treated diabetes, HPLBII-P was raised (p = 0.02) as compared to women treated with oral antidiabetics only. In the ULSAM cohort, HPLBII-P was correlated to NGAL, KIM-1, and albumin in urine both in non-DM (all three biomarkers; p < 0.0001) and in DM (NGAL; p = 0.002, KIM-1; p = 0.02 and albumin; p = 0.01). Plasma glucose and HbA1c in blood showed correlations to U-HPLBII-P (r = 0.58, p < 0.001 and r = 0.42, p = 0.004, respectively). U-HPLBII-P and cathepsin S were correlated in the ULSAM group (r = 0.50, p < 0.001). No correlations were observed between U-HPLBII-P and serum creatinine or cystatin C. Conclusions: The urine measurement of HPLBII-P has the potential to become a novel and useful biomarker in the monitoring of glomerular activity in diabetes mellitus.

The Human Phospholipase B-II Precursor (HPLBII-P) in Urine as a Novel Biomarker of Glomerular Activity in COVID-19 and Diabetes Mellitus.

Background: The human phospholipase B-II precursor (HPLBII-P) was originally purified from white blood cells but is also found in other cellular structures, such as kidney glomeruli and tubuli. The objective of this report was to investigate the relationship of HPLBII-P in urine to acute kidney injury in patients with COVID-19. Methods: Urine was collected at admission from 132 patients with COVID-19 admitted to the intensive care units (ICUs) because of respiratory failure. HPLBII-P was measured using a sensitive ELISA. For comparison, human neutrophil lipocalin (HNL) was measured in urine, using the ELISA configured with the monoclonal antibody 763/8F, as a sign of tubular affection in addition to routine biomarkers of kidney disease. Results: Overall, the concentrations of urinary HPLBII-P were almost 3-fold higher in patients with COVID-19 compared to healthy controls (p < 0.0001) and with significantly higher concentrations even in patients with COVID-19 without signs of acute kidney injury (AKI) (p < 0.001). HPLBII-P was further increased in patients with AKI (p < 0.02). HPLBII-P was significantly increased in patients with diabetes mellitus (p = 0.0008) and correlated to plasma glucose (r = 0.29, p = 0.001) and urine albumin concentrations (r = 0.55, p < 0.001). Conclusions: Urine concentrations of HPLBII-P are highly raised in the urine of patients with COVID-19 and relate to AKI and diabetes mellitus. HPLBII-P may reflect glomerular injury and/or increased glomerular cell activity in SARS-CoV-2 infections.

Measurement of natriuretic peptides at the point of care in the emergency and ambulatory setting: current status and future perspectives.

The measurement of natriuretic peptides (NPs), B-type NP or N-terminal pro-B-type NP, can be an important tool in the diagnosis of acute heart failure in patients presenting to an Emergency Department (ED) with acute dyspnea, according to international guidelines. Studies and subsequent meta-analyses are mixed on the absolute value of routine NP assessment of ED patients. However, levels of NPs are likely to be used also to guide treatment and to assess risk of adverse outcomes in other patients at risk of developing heart failure, including those with pulmonary embolism or diabetes, or receiving chemotherapy. Natriuretic peptide levels, like other biomarkers, can now be measured at the point of care (POC). We have reviewed the current status of NP measurement together with the potential contribution of POC measurement of NPs to clinical care delivery in the emergency and other settings. Several POC systems for measuring NP levels are now available: these produce test results within 15 minutes and appear sufficiently sensitive and robust to be used routinely in diagnostic evaluations. Point-of-care systems could be used to assess NP levels in the ED and community outpatient settings to monitor the risk of acute heart failure. Furthermore, the use of protocol-driven POC testing of NP within the time frame of a patient consultation in the ED may facilitate and accelerate the throughput and disposition of at-risk patients. Appropriately designed clinical trials will be needed to confirm these potential benefits. It is also important that processes of care delivery are redesigned to take full advantage of the faster turnaround times provided by POC technology.

Cardiac troponin assay classification by both clinical and analytical performance characteristics: a study on outcome prediction.

BACKGROUND: Cardiac troponin assays have been classified according to whether they measure the 99th percentile concentration of a healthy reference population with imprecision (expressed as CV) of ≤10%, between 10% and 20%, or >20%. Assays in these categories have been deemed "guideline acceptable," "clinically usable," or "not acceptable," respectively. We compared four widely used "clinically usable" cardiac troponin I (cTnI) assays with an assay designated "not acceptable" for accuracy in predicting the clinical outcome of death. METHODS: Blood was collected from 259 men and 249 women, mean (SD) age 68.8 (17.8) and 70.2 (17.8) years, respectively, admitted to the emergency department for suspected myocardial infarction. We measured cTnI by the Access, Architect, i-Stat, Stratus CS, and VIDAS assays. Deaths in this population were recorded over a 31-month period. RESULTS: We found VIDAS cTnI assay measurement CVs of 10% and 20% at concentrations of 0.04 and 0.02 µg/L, respectively. Comparing at the 10% CV cutoff concentration, VIDAS cTnI was less sensitive than the Access and Architect assays (P < 0.001) but more sensitive than i-Stat (P < 0.001) and Stratus CS (P < 0.001) in identifying patients with poor outcomes. At the 20% CV cutoff, the VIDAS assay was equivalent to the other assays in identifying patients with poor outcomes. CONCLUSIONS: For outcome prediction, the VIDAS cTnI assay was clinically equivalent or superior to other cTnI assays judged to be acceptable from a pure analytical standpoint. Thus, comparison of cardiac troponin assays should consider not only analytical performance, but also clinical performance characteristics.

Factors influencing the 99th percentile of cardiac troponin I evaluated in community-dwelling individuals at 70 and 75 years of age.

BACKGROUND: We aimed to investigate the effects of sex, prevalent cardiovascular disease (CVD), and aging on the 99th percentile of cardiac troponin I (cTnI). METHODS: cTnI was measured using a high-sensitivity assay (Abbott Diagnostics) in 814 community-dwelling individuals at both 70 and 75 years of age. We determined the cTnI 99th percentiles separately using nonparametric methods in the total sample, in men and women, and in individuals with and without CVD. RESULTS: The cTnI 99th percentile at baseline was 55.2 ng/L for the total cohort. Higher 99th percentiles were noted in men (69.3 ng/L) and individuals with CVD (74.5 ng/L). The cTnI 99th percentile in individuals free from CVD at baseline (n = 498) increased by 51% from 38.4 to 58.0 ng/L during the 5-year observation period. Relative increases ranging from 44% to 83% were noted across all subgroups. Male sex [odds ratio, 5.3 (95% CI, 1.5-18.3)], log-transformed N-terminal pro-B-type natriuretic peptide [odds ratio, 1.9 (95% CI, 1.2-3.0)], and left-ventricular mass index [odds ratio, 1.3 (95% CI, 1.1-1.5)] predicted increases in cTnI concentrations from below the 99th percentile (i.e., 38.4 ng/L) at baseline to concentrations above the 99th percentile at the age of 75 years. CONCLUSIONS: cTnI concentration and its 99th percentile threshold depend strongly on the characteristics of the population being assessed. Among elderly community dwellers, higher concentrations were seen in men and individuals with prevalent CVD. Aging contributes to increasing concentrations, given the pronounced changes seen with increasing age across all subgroups. These findings should be taken into consideration when applying cTnI decision thresholds in clinical settings.

Short- and long-term individual variation in cardiac troponin in patients with stable coronary artery disease.

BACKGROUND: A rise or fall of cardiac troponin is a prerequisite for the diagnosis of acute myocardial infarction. Defining significant changes requires knowledge of both biological and analytical variation. The short-term biological variation of cardiac troponin in healthy individuals is 3%-48%. However, healthy individuals may not be representative for patients in whom cardiac troponin measurement is often of clinical importance. Therefore, we studied the individual variation of cardiac troponin in patients with symptoms of stable coronary artery disease. METHODS: Twenty-four patients scheduled for elective coronary angiography were included. Blood samples were drawn once at enrollment and serially at six 4-h intervals on the day before coronary angiography. Cardiac troponin was measured with hs-cTn assays from Abbott Laboratories (premarket cTnI assay) and Roche Diagnostics (Elecsys(®) cTnT assay with two different lots). RESULTS: The short-term individual variation in cardiac troponin I (cTnI) was 14%, the reference change value (RCV) 49%, and RCV-log-normal (rise/fall) 54%/-35%. The corresponding values for cTnT were 7%, 23%, and 26%/-21%. The long-term variation for cTnI was 24%, RCV 69%, and RCV-log-normal (rise/fall) 97%/-49%. The corresponding values for cTnT were 11%, 32%, and 37%/-27%. CONCLUSIONS: The short-term individual variation of cardiac troponin in patients with symptoms of stable coronary artery disease is similar to the biological variation previously demonstrated in healthy individuals. Our results suggest that a change in cardiac troponin concentrations of >50% can be used in attempting to diagnose acute myocardial injury. To detect significant long-term changes in cardiac troponin concentrations, larger changes will be required.

Prognostic implications of changes in cardiac troponin I levels in patients with non-ST elevation acute coronary syndrome.

OBJECTIVE: Information is limited on the prognostic implications of cardiac troponin I (cTnI) changes during the first days of non-ST elevation acute coronary syndrome (NSTE-ACS). METHODS: High-sensitivity cTnI levels were measured at study inclusion and after 48 h in 1615 conservatively managed NSTE-ACS patients from the Global Use of Strategies To Open Occluded Coronary Arteries (GUSTO) IV trial. RESULTS: Patients with moderately increased cTnI levels and without a relevant decrease over time had a significantly raised mortality at 30 days and 1 year. No relevant associations between cTnI changes and recurrent myocardial infarction were seen. CONCLUSION: The cTnI change is predictive for subsequent mortality in selected conservatively managed NSTE-ACS patients.

Association of plasma neutrophil gelatinase-associated lipocalin (NGAL) with sepsis and acute kidney dysfunction.

OBJECTIVE: Neutrophil gelatinase-associated lipocalin (NGAL) is secreted by injured kidney cells as well as by activated neutrophils in response to bacterial infections. We assessed the influence of acute renal dysfunction on the association between plasma NGAL and sepsis. METHODS: NGAL was measured daily in 138 critically ill patients. Simultaneous recordings of sepsis status and fluctuations in renal function were made. RESULTS: Elevated NGAL was associated with sepsis independent of level of acute renal dysfunction. A cut-off value of 98 ng/mL distinguished sepsis from systemic inflammation with high sensitivity (0.77) and specificity (0.79). CONCLUSIONS: Plasma NGAL can help clinicians to identify bacterial infections in critically ill patients.

Evaluation of four sensitive troponin assays for risk assessment in acute coronary syndromes using a new clinically oriented approach for comparison of assays.

BACKGROUND: Measurement of cardiac troponin T or I (cTnT; cTnI) is useful for risk prediction in acute coronary syndromes. The objective of the present study was to compare the prognostic capacity of four sensitive cardiac troponin assays using a new method for comparison. METHODS: Cardiac troponin was analyzed in serum samples from 1335 patients with acute coronary syndrome using the Elecsys high sensitivity TnT (hs-cTnT), ARCHITECT STAT high sensitivity TnI (hs-cTnI), Access AccuTnI (Acc-cTnI) and Architect cTnI (Arc-cTnI) assays. All patients were followed for 30 days regarding death and acute myocardial infarction (AMI), and for 1 year regarding mortality. RESULTS: By receiver operating characteristic (ROC) curve analyses, there were only minor differences in the area under the curves (AUC) between the assays. At a given sensitivity of 85% the hs-cTnT, Arc-cTnI and Acc-cTnI assays showed comparable specificities, while 90% or higher sensitivity was only possible to achieve with the hs-cTnT, hs-cTnI and Acc-cTnI assays. The highest odds ratios for death/AMI at 30 days and death at 1 year, respectively, were reached by cut-off levels yielding 95% sensitivity; these cut-off levels were below the respective 99th percentile levels. CONCLUSIONS: By the adoption of a new method for the comparison of cardiac troponin assays we showed that the hs-cTnT, hs-cTnI and Acc-cTnI assays had comparable prognostic properties, while the Arc-cTnI assay had inferior prognostic sensitivity.

Blood eosinophils to direct corticosteroid treatment of exacerbations of chronic obstructive pulmonary disease: a randomized placebo-controlled trial.

RATIONALE: Exacerbations of chronic obstructive pulmonary disease (COPD) and responses to treatment are heterogeneous. OBJECTIVES: Investigate the usefulness of blood eosinophils to direct corticosteroid therapy during exacerbations. METHODS: Subjects with COPD exacerbations were entered into a randomized biomarker-directed double-blind corticosteroid versus standard therapy study. Subjects in the standard arm received prednisolone for 2 weeks, whereas in the biomarker-directed arm, prednisolone or matching placebo was given according to the blood eosinophil count biomarker. Both study groups received antibiotics. Blood eosinophils were measured in the biomarker-directed and standard therapy arms to define biomarker-positive and -negative exacerbations (blood eosinophil count > and ≤ 2%, respectively). The primary outcome was to determine noninferiority in health status using the chronic respiratory questionnaire (CRQ) and in the proportion of exacerbations associated with a treatment failure between subjects allocated to the biomarker-directed and standard therapy arms. MEASUREMENTS AND MAIN RESULTS: There were 86 and 80 exacerbations in the biomarker-directed and standard treatment groups, respectively. In the biomarker-directed group, 49% of the exacerbations were not treated with prednisolone. CRQ improvement after treatment in the standard and biomarker-directed therapy groups was similar (0.8 vs. 1.1; mean difference, 0.3; 95% confidence interval, 0.0-0.6; P = 0.05). There was a greater improvement in CRQ in biomarker-negative exacerbations given placebo compared with those given prednisolone (mean difference, 0.45; 95% confidence interval, 0.01-0.90; P = 0.04). In biomarker-negative exacerbations, treatment failures occurred in 15% given prednisolone and 2% of those given placebo (P = 0.04). CONCLUSIONS: The peripheral blood eosinophil count is a promising biomarker to direct corticosteroid therapy during COPD exacerbations, but larger studies are required.