A review of causes and systemic approach to cardiac troponin elevation

Implications of High Sensitivity Troponin Levels After Lung Transplantation

Trends in high-sensitivity cardiac troponin I (hs-cTnI) after lung transplant (LT) and its clinical value are not well stablished. This study aimed to determine kinetics of hs-cTnI after LT, factors impacting hs-cTnI and clinical outcomes. LT recipients from 2015 to 2017 at Toronto General Hospital were included. Hs-cTnI levels were collected at 0-24 h, 24-48 h and 48-72 h after LT. The primary outcome was invasive mechanical ventilation (IMV) >3 days. 206 patients received a LT (median age 58, 35.4% women; 79.6% double LT). All patients but one fulfilled the criteria for postoperative myocardial infarction (median peak hs-cTnI = 4,820 ng/mL). Peak hs-cTnI correlated with right ventricular dysfunction, >1 red blood cell transfusions, bilateral LT, use of EVLP, kidney function at admission and time on CPB or VA-ECMO. IMV>3 days occurred in 91 (44.2%) patients, and peak hs-cTnI was higher in these patients (3,823 vs. 6,429 ng/mL, p < 0.001 after adjustment). Peak hs-cTnI was higher among patients with had atrial arrhythmias or died during admission. No patients underwent revascularization. In summary, peak hs-TnI is determined by recipient comorbidities and perioperative factors, and not by coronary artery disease. Hs-cTnI captures patients at higher risk for prolonged IMV, atrial arrhythmias and in-hospital death.

Femtosecond laser-induced fluorescence for rapid monitoring of cardiac troponin 1 as a cardiovascular disease biomarker

Medical diagnosis usually requires blood analysis of various biomarkers which are essential for disease detection and health status monitoring. Cardiac troponin 1 (cTn1) is a protein member of the cardiac troponin complex used for the diagnosis of several pathologies associated with cardiomyocyte necrosis. Laser-induced fluorescence (LIF) is a technique with high sensitivity and specificity, and it is one of the most significant developments used as an analytical tool for qualitative and quantitative analysis. The current study investigated the potential application of femtosecond LIF as a novel detection technique for rapid monitoring of cTn1 in clinical analysis. In the present study, the cTn1 (8 ng/ml) was excited over wavelengths ranging from 350 to 400 nm, and the LIF spectra were recorded. The results demonstrated that the maximum fluorescence intensity was observed at an excitation wavelength of 350 nm, with an emitted fluorescence peak centeredat 494 nm. At an excitation wavelength of 350 nm, different concentrations of cTn1 have been investigated and LIF spectra were obtained. The results revealed that the fluorescence peak intensity is concentration-dependent and increases linearly with increasing cTn1 concentration. These findings show that femtosecond LIF presents a unique, highly selective, precise, and direct approach to monitoring cTn1.

A 73-Year-Old Woman with a Fall

A 73-Year-Old Woman with a FallA 73-year-old woman who had a cholecystectomy 2 months ago presented for evaluation after a fall. How do you approach the evaluation, and what is your differential diagnosis?

Association of high-sensitivity troponin T with outcomes in asymptomatic non-severe aortic stenosis: a post-hoc substudy of the SEAS trial

BACKGROUND

High-sensitivity Troponin T (hsTnT), a biomarker of cardiomyocyte overload and injury, relates to aortic valve replacement (AVR) and mortality in severe aortic stenosis (AS). However, its prognostic value remains unknown in asymptomatic patients with AS. We aimed to investigate if an hsTnT level >14 pg/mL (above upper limit of normal 99th percentile) is associated with echocardiographic AS-severity, subsequent AVR, ischaemic coronary events (ICE), and mortality in asymptomatic patients with non-severe AS.

METHODS

In this post-hoc sub-analysis of the multicentre, randomised, double-blind, placebo-controlled SEAS trial (ClinicalTrials.gov, NCT00092677), we included asymptomatic patients with mild to moderate-severe AS. We ascertained baseline and 1-year hsTnT concentrations and examined the association between baseline levels and the risk of the primary composite endpoint, defined as the first event of all-cause mortality, isolated AVR (without coronary artery bypass grafting (CABG)), or ICE. Multivariable regressions and competing risk analyses examined associations of hsTnT level >14 pg/mL with clinical correlates and 5-year risk of the primary endpoint.

FINDINGS

Between January 6, 2003, and March 4, 2004, a total of 1873 patients were enrolled in the SEAS trial, and 1739 patients were included in this post-hoc sub-analysis. Patients had a mean (SD) age of 67.5 (9.7) years, 61.0% (1061) were men, 17.4% (302) had moderate-severe AS, and 26.0% (453) had hsTnT level >14 pg/mL. The median hsTnT difference from baseline to 1-year was 0.8 pg/mL (IQR, -0.4 to 2.3). In adjusted linear regression, log(hsTnT) did not correlate with echocardiographic AS severity (p = 0.36). In multivariable Cox regression, a hsTnT level >14 pg/mL vs. hsTnT ≤14 pg/mL was associated with an increased risk of the primary composite endpoint (HR, 1.41; 95% CI, 1.18-1.70; p = 0.0002). In a competing risk model of first of the individual components of the primary endpoint, a hsTnT level >14 pg/mL was associated with ICE risk (HR 1.71; 95% CI, 1.23-2.38; p = 0.0013), but not with isolated AVR (p = 0.064) or all-cause mortality (p = 0.49) as the first event.

INTERPRETATION

hsTnT level is within the reference range (≤14 pg/mL) in 3 out of 4 non-ischaemic patients with asymptomatic mild-to-moderate AS and remains stable during a 1-year follow-up regardless of AS-severity. An hsTnT level >14 pg/mL was mainly associated with subsequent ICE, which suggest that hsTnT concentration is primarily a risk marker of subclinical coronary atherosclerotic disease.

FUNDING

Merck & Co., Inc., the Schering-Plough Corporation, the Interreg IVA program, Roche Diagnostics Ltd., and Gangstedfonden. Open access publication fee funding provided by prof. Olav W. Nielsen and Department of Cardiology, Bispebjerg University Hospital, Denmark.

The liver and blood cells are responsible for creatine kinase clearance in blood Circulation: A retrospective study among different human diseases

BACKGROUND

Muscle damage leads to increased serum creatine kinase (CK) levels in diseases such as acute myocardial infarction. Still, many individuals have abnormal serum CK activities lacking muscle-related diagnoses. The current study hypothesized that failed or overactivated CK clearance by non-muscle organs/tissues might be responsible for increased or decreased CK activities in blood.

METHODS

We analyzing 37,081 independent CK test results in 36 human diseases during the past 5 y.

RESULTS

We found that 33 out of 36 diseases were associated with decreased median CK activities compared to healthy controls. Besides muscle damage-related conditions, the highest mean CK activities were observed in hepatitis and cirrhosis. In contrast, 6 blood cell-related illnesses had the lowest mean CK values. ROC analysis showed that CK activities were the best biomarkers (AUC: 0.80-0.94) for the 6 blood-related diseases, especially myeloproliferative disorders. The principal component analysis revealed that the same category of diseases, such as liver-, blood -, kidney-, cancers, and vascular-related diseases, had clustered CK distributions.

CONCLUSIONS

We proposed that the liver and blood cells were mainly responsible for CK clearance in blood circulation based on overall results. The testable mechanisms were presented and discussed.

Associations between short-term exposure to PM2.5 and cardiomyocyte injury in myocardial infarction survivors in North Carolina

Objective

Short-term ambient fine particulate matter (PM_2.5) is associated with adverse cardiovascular events including myocardial infarction (MI). However, few studies have examined associations between PM_2.5 and subclinical cardiomyocyte damage outside of overt cardiovascular events. Here we evaluate the impact of daily PM_2.5 on cardiac troponin I, a cardiomyocyte specific biomarker of cellular damage.

Methods

We conducted a retrospective cohort study of 2924 patients identified using electronic health records from the University of North Carolina Healthcare System who had a recorded MI between 2004 and 2016. Troponin I measurements were available from 2014 to 2016, and were required to be at least 1 week away from a clinically diagnosed MI. Daily ambient PM_2.5 concentrations were estimated at 1 km resolution and assigned to patient residence. Associations between log-transformed troponin I and daily PM_2.5 were evaluated using distributed lag linear mixed effects models adjusted for patient demographics, socioeconomic status and meteorology.

Results

A 10 µg/m³ elevation in PM_2.5 3 days before troponin I measurement was associated with 0.06 ng/mL higher troponin I (95% CI=0.004 to 0.12). In stratified models, this association was strongest in patients that were men, white and living in less urban areas. Similar associations were observed when using 2-day rolling averages and were consistently strongest when using the average exposure over the 5 days prior to troponin I measurement.

Conclusions

Daily elevations in PM_2.5 were associated with damage to cardiomyocytes, outside of the occurrence of an MI. Poor air quality may cause persistent damage to the cardiovascular system leading to increased risk of cardiovascular disease and adverse cardiovascular events.

Aptamers Targeting Cardiac Biomarkers as an Analytical Tool for the Diagnostics of Cardiovascular Diseases: A Review

The detection of cardiac biomarkers is used for diagnostics, prognostics, and the risk assessment of cardiovascular diseases. The analysis of cardiac biomarkers is routinely performed with high-sensitivity immunological assays. Aptamers offer an attractive alternative to antibodies for analytical applications but, to date, are not widely practically implemented in diagnostics and medicinal research. This review summarizes the information on the most common cardiac biomarkers and the current state of aptamer research regarding these biomarkers. Aptamers as an analytical tool are well established for troponin I, troponin T, myoglobin, and C-reactive protein. For the rest of the considered cardiac biomarkers, the isolation of novel aptamers or more detailed characterization of the known aptamers are required. More attention should be addressed to the development of dual-aptamer sandwich detection assays and to the studies of aptamer sensing in alternative biological fluids. The universalization of aptamer-based biomarker detection platforms and the integration of aptamer-based sensing to clinical studies are demanded for the practical implementation of aptamers to routine diagnostics. Nevertheless, the wide usage of aptamers for the diagnostics of cardiovascular diseases is promising for the future, with respect to both point-of-care and laboratory testing.

Retrospective validation of a machine learning clinical decision support tool for myocardial infarction risk stratification

Diagnosis and appropriate intervention for myocardial infarction (MI) are time-sensitive but rely on clinical measures that can be progressive and initially inconclusive, underscoring the need for an accurate and early predictor of MI to support diagnostic and clinical management decisions. The objective of this study was to develop a machine learning algorithm (MLA) to predict MI diagnosis based on electronic health record data (EHR) readily available during Emergency Department assessment. An MLA was developed using retrospective patient data. The MLA used patient data as they became available in the first 3 h of care to predict MI diagnosis (defined by International Classification of Diseases, 10th revision code) at any time during the encounter. The MLA obtained an area under the receiver operating characteristic curve of 0.87, sensitivity of 87% and specificity of 70%, outperforming the comparator scoring systems TIMI and GRACE on all metrics. An MLA can synthesize complex EHR data to serve as a clinically relevant risk stratification tool for MI.

Outcomes associated with the high sensitivity cardiac troponin testing in patients presenting with non-cardiovascular disorders

There are limited data regarding the utility of troponin testing in patients presenting with non-cardiovascular (CV) symptoms as the primary manifestation. The study population comprised 2057 patients who presented to the emergency department (ED) of a US healthcare system with non-CV symptoms as the primary manifestation between January and September 2018. We compared the effect of high-sensitivity cardiac troponin T (hs-cTnT) (n = 901) after its introduction vs. 4th generation cTnT (n = 1156) on the following outcomes measures: ED length of stay (LOS), coronary tests/procedures (angiography or stress test), and long-term mortality. Mean age was 64 ± 17 yrs., and 47% were female. Primary non-CV manifestations included pneumonia, obstructive pulmonary disease, infection, abdominal-complaint, and renal failure. Mean follow up was 9 ± 4 months. Patients' demographics and medical history were clinically similar between the two troponin groups. A second cTn test was obtained more frequently in the hs-cTnT than cTnT (84% vs. 32%; p < 0.001), possibly leading to a longer ED stay (8.1 ± 8.2 h vs 5.6 ± 3.4 h, respectively; p < 0.001). Coronary tests/procedures were performed at a significantly higher rate in the hs-cTnT than cTnT following the introduction of the hs-cTnT test (28% vs. 22%, p < 0.001). Multivariate analysis showed that following the introduction of hs-cTnT testing, there was a significant 27% lower risk of long-term mortality from ED admission through follow-up (HR = 0.73, 95%CI 0.54-0.98; p = 0.035). In conclusion, we show that in patients presenting primarily with non-CV disorders, the implementation of the hs-cTnT was associated with a higher rate of diagnostic coronary procedures/interventions, possibly leading to improved long-term survival rates.

Detection of Early Myocardial Injury in Children with Ventricular Septal Defect Using Cardiac Troponin I and Two-Dimensional Speckle Tracking Echocardiography

Children with ventricular septal defects (VSDs) are subjected to hemodynamic overload which causes myocardial injury and subsequent heart failure. Early stages of myocardial damage cannot be detected by conventional echocardiography. Two-dimensional speckle tracking echocardiography (2D-STE) and cardiac troponin I (cTnI) have been recently introduced as more accurate tools for early assessment of cardiovascular diseases. The purpose of this study is to evaluate the role of cardiac troponin I (cTnI) and 2D-STE in the early detection of VSD-induced myocardial injury. Thirty children with VSD (symptomatic and asymptomatic) and 30 controls were assessed serologically by measuring serum cTnI and by conventional echocardiography. STE was performed to measure the averaged global peak longitudinal systolic stain [G peak SL(AVG)]. Serum cTnI levels were significantly higher in patients when compared to controls (P < 0.05) and in the symptomatic group when compared to the asymptomatic group (P < 0.05). Serum cTn I level correlated positively with the left atrial (r = 0.37, P = 0.045) and left ventricular dimensions (r = 0.46, P = 0.01) and negatively with the G peak SL(AVG) (r = -0.39, P = 0.03). There were no statistically significant differences between patients and controls or between symptomatic and asymptomatic groups with regard to the G peak SL(AVG). The peak longitudinal systolic strain (measured by 2D-STE) is not affected despite the elevation of serum cTnI. Serum cTnI is a sensitive marker for early detection of myocardial injury in VSD patients even before the development of ventricular dilatation or dysfunction.

Novel Invasive and Noninvasive Cardiac-Specific Biomarkers in Obesity and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of fatality and disability worldwide regardless of gender. Obesity has reached epidemic proportions in population across different regions. According to epidemiological studies, CVD risk markers in childhood obesity are one of the significant risk factors for adulthood CVD, but have received disproportionally little attention. This review has examined the evidence for the presence of traditional cardiac biomarkers (nonspecific; lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, myoglobulin, glycogen phosphorylase isoenzyme BB, myosin light chains, ST2, and ischemia-modified albumin) and novel emerging cardiac-specific biomarkers (cardiac troponins, natriuretic peptides, heart-type fatty acid-binding protein, and miRNAs). Besides, noninvasive anatomical and electrophysiological markers (carotid intima-media thickness, coronary artery calcification, and heart rate variability) in CVDs and obesity are also discussed. Modifiable and nonmodifiable risk factors associated with metabolic syndrome in the progression of CVD, such as obesity, diabetes, hypertension, dyslipidemia, oxidative stress, inflammation, and adipocytokines are also outlined. These underlying prognostic risk factors predict the onset of future microvascular and macrovascular complications. The understanding of invasive and noninvasive cardiac-specific biomarkers and the risk factors may yield valuable insights into the pathophysiology and prevention of CVD in a high-risk obese population at an early stage.

Perioperative Cardiac Troponin I Levels in Patients Undergoing Total Hip and Total Knee Arthroplasty: A Single Center Study

Background

Cardiac injury is one of the significant perioperative complications in major orthopedic surgeries and its early diagnosis is useful in the reduction of postoperative comorbidity. The cardiac troponin is a sensitive and specific biomarker for detecting this damage.

Objectives

The aim of this study was to evaluate the levels of perioperative cardiac troponin I (cTnI) before and after arthroplasty in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). The effects of related variables and probable major cardiac complications were evaluated in this study.

Methods

For one year, in a prospective, cross-sectional study, the serum levels of cTnI before and 48 hours after arthroplasty were evaluated in 52 patients. Possible contributing factors including age, gender, body mass index (BMI), daily activity, history of hospitalization due to cardiovascular diseases, underlying illness, and medications were recorded. The Chi-square test, Pearson correlation, and Spearman test were used to examine the relationship between variables.

Results

The mean cTnI increased significantly after arthroplasty (P < 0.001). There was no significant relationship between age (P = 0.708), gender (P = 0.225), BMI (P = 0.195), daily activity (0.441), underlying illness (P = 0.244), and cTnI levels after arthroplasty. Linear regression showed BMI was significantly correlated with troponin changes (P = 0.006). Five patients had heart palpitations and one had chest pain, but none of the patients had any findings in favor of cardiac injury.

Conclusions

cTnI levels after THA and TKA increased significantly, but this elevation was in the normal range. In addition, none of them had a new cardiac complication after arthroplasty.

Ready for Prime Time? Biomarkers in Sepsis

Sepsis is a common condition managed in the emergency department. Current diagnosis relies on physiologic criteria and suspicion of a source of infection using history, physical examination, laboratory studies, and imaging studies. The infection triggers a host response with the aim to destroy the pathogen, and this response can be measured. A reliable biomarker for sepsis should assist with earlier diagnosis, improve risk stratification, or improve clinical decision making. Current biomarkers for sepsis include lactate, troponin, and procalcitonin. This article discusses the use of lactate, procalcitonin, troponin, and novel biomarkers for use in sepsis.

Cardiac troponin T is an important predictor of mortality after cardiac surgery

PURPOSE

Serum troponin (cTnT) levels, a commonly measured biomarker of myocardial injury, has rarely been considered in risk models after cardiac surgery.

MATERIALS AND METHODS

Retrospective study of patients undergoing any cardiac surgery between 2004 and 2012. Patients with a history of recent myocardial injury (<21 days) were excluded. The minimum P value approach was used to determine categories of peak cTnT associated with in-hospital death. A multivariable analysis was performed to identify independent predictors of mortality.

RESULTS

A total of 5318 patients without evidence of preoperative ischemia underwent a number of cardiac surgical interventions ranging from isolated coronary revascularization to combined valve coronary artery bypass grafting. The unadjusted in-hospital mortality rate was 3.3% (n = 175 patients). Four categories of peak cTnT were identified using the minimum P value approach: less than or equal to 0.6 ng/mL, 0.7 to 1.9 ng/mL, 2.0 to 3.1 ng/mL, and greater than 3.1 ng/mL with unadjusted mortality rates of 1.0%, 3.6%, 10.1%, and 33.1%, respectively. Multivariate logistic regression demonstrated that all peak cTnT levels greater than 0.6 ng/mL were independent predictors of in-hospital mortality in a dose-dependent manner.

CONCLUSIONS

We demonstrate that in patients without preoperative myocardial ischemia, the demonstration of myocardial injury (>0.6 ng/mL) in the postoperative period is highly predictive of in-hospital death.

Echocardiography and cardiac biomarkers in patients with non-small cell lung cancer treated with platinum-based chemotherapy

Background

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and remains an important cause of cancer death worldwide. Platinum-based chemotherapy (PBC) for NSCLC can modify outcome while the risk of cardiotoxicity remains poorly researched. We aimed to evaluate the incidence and severity of cardiac injury during PBC in patients with NSCLC and to identify patients at risk.

Methods

This was a single-centre, prospective, observational study of patients with early and advanced stage NSCLC referred for PBC. In addition to standard care, patients were examined and evaluated for cardiotoxicity before the first dose (visit 1), at the last dose (visit 2) and 6 months after the last dose of PBC (visit 3). Cardiotoxicity (at visit 2 and 3) was defined as increase in the ultrasensitive troponin T, N-terminal pro-B type natriuretic peptide or decrease in left ventricular ejection fraction (LVEF).

Results

Overall, 41 patients (mean age 61 ± 9; 54% men; 68% advanced lung cancer) were included. The median number of PBC cycles was 4. During the study period, there were no incidents of heart failure, and 3 deaths caused by tumour progression were recorded. The mean values of biomarkers and LVEF did not change significantly (p > 0.20). However, 10 (25%) had cardiotoxicity which was independently associated with a history of ischemic heart disease (p = 0.026).

Conclusions

In NSCLC, cardiac assessment and lifestyle modifications may be pursued in patients with a history of cardiac disease and in patients with longer life expectancy.

Circulating MicroRNA and Long Noncoding RNA as Biomarkers of Cardiovascular Diseases

Although >85% of the human genome is transcribed, only <2% is transcribed into protein-coding RNA (messenger RNA, mRNA). Many thousands of noncoding RNAs are transcribed and recognized as functional RNAs with diverse sizes, structures, and biological functions. Based on size, noncoding RNA can be generally divided into two subgroups: short noncoding RNA (<200 nucleotides including microRNA or miRNA) and long noncoding RNA (lncRNA, >200 nucleotides). It is now clear that these RNAs fulfil critical roles as transcriptional and post-transcriptional regulators and as guides of chromatin-modifying complexes. Although not translated into protein, noncoding RNAs can regulate cardiac function through diverse mechanisms and their dysregulation is increasingly linked with cardiovascular pathophysiology. Furthermore, a series of recent studies have discovered that noncoding RNAs can be found in the bloodstream and some species are remarkably stable. This has raised the possibility that such noncoding RNAs may be measured in body fluids and serve as novel diagnostic biomarkers. Here, we summarize the current knowledge of noncoding RNAs' function and biomarker potential in cardiac diseases, concentrating mainly on circulating miRNAs and lncRNAs. J. Cell. Physiol. 231: 751-755, 2016. © 2015 Wiley Periodicals, Inc.

Prognosis of Troponin-Positive Patients with Non-Obstructive Coronary Artery Disease

Introduction

Troponin elevation is an independent risk factor for mortality, but the prognosis of patients with troponin elevation and non-obstructive coronary artery disease (CAD) is unknown. Recent data have suggested an increased risk of mortality. This study was performed to further investigate the outcomes of troponin-positive patients with obstructive and non-obstructive CAD.

Methods

A retrospective cohort analysis was performed of all patients with raised troponin presenting to Kettering General Hospital (January 2010 to December 2011, n = 1,351). The patients who had angiograms were stratified anatomically into obstructive CAD and non-obstructive CAD (≤50% stenosis). The obstructive CAD group (O-CAD) was sub-analyzed by management strategy: emergency re-vascularization (<12 h), urgent, delayed, and medically managed. Patients with non-obstructive CAD were grouped by the cause of the raised troponin if this could be identified (NO-CAD-I) or cause remained unidentified (NO-CAD-U). The major adverse cardiac and cerebrovascular event (MACCE) and mortality rates were calculated at 30 days and 1-year follow-up.

Results

There was a preponderance of hypertension and severe renal impairment in the non-obstructive CAD group. The patients with NO-CAD-U were a low-risk group (MACCE at 1-year follow-up = 0). The remaining NO-CAD-I group had a similar risk to the O-CAD group for MACCE and mortality at 30 days and 1-year follow-up. In fact, at 1-year follow-up, the NO-CAD-I patients when compared with the subgroups of O-CAD, had higher MACCE rates and mortality compared with the emergency re-vascularized group [MACCE: relative risk (RR) (95% CI) = 2.27 (1.29–3.40), P = 0.0047; mortality: RR (95% CI) = 2.08 (1.10–3.93), P = 0.024]. This was driven by higher risk non-cardiac death [RR (95% CI) = 4.10 (1.53–10.99), P = 0.005].

Conclusion

Patients with identified cause for raised troponin and non-obstructive CAD are at equivalent risk of MACCE and mortality at 30 days and 1-year follow-up compared to those with obstructive CAD.

Electronic supplementary material

The online version of this article (doi:10.1007/s40119-014-0027-6) contains supplementary material, which is available to authorized users.

A comparison of markers of myocardial injury and their relation to nutritional parameters in hemodialysis patients

BACKGROUND

Serum cardiac troponin T (cTnT) is a valuable marker of ischemic heart disease (IHD) and left ventricular hypertrophy, as well as a mortality predictor in hemodialysis populations. We compared the value of cTnT, creatinine kinase (CK)-MB mass and myoglobin as mortality predictors in our hemodialysis patients and evaluated their relation to nutritional status.

METHODS

A total of 118 hemodialysis patients were prospectively studied from January 2004 to April 2013. Clinical and laboratory evaluations during the 12-month baseline period included the history of IHD, signs of left ventricular hypertrophy (LVH), Kt/V and serum cardiac markers together with the percentage of body fat (%fat), mid-arm circumference (MAC), mid-arm muscle circumference (MAMC), triceps skinfold (TSF) and BMI.

RESULTS

Underweight patients had significantly higher cTnT values (Mann-Whitney, p<0.05). Correlation analysis (Spearman) showed an inverse association between cTnT and TSF (ρ=-0.22, p<0.05), as well as between CK-MB mass and TSF (ρ=-0.26, p<0.01). In men cTnT also correlated inversely with %fat (ρ=-0.27, p<0.05) and BMI (ρ=-0.33, p<0.05). In addition, myoglobin was correlated significantly with MAC, MAMC and albumin. Among cardiac markers cTnT was the only independent variable predicting mortality (Multivariate Cox regression, HR=1.04 CI (1.01-1.07); p<0.01; measurement units 0.01 μg/L).

CONCLUSION

Troponin T and CK-MB mass were significantly elevated in the underweight patient group. Troponin T was the only independent cardiac marker predictor of all cause mortality in our hemodialysis patients.

Trends in laboratory test volumes for Medicare Part B reimbursements, 2000-2010

CONTEXT

Changes in reimbursements for clinical laboratory testing may help us assess the effect of various variables, such as testing recommendations, market forces, changes in testing technology, and changes in clinical or laboratory practices, and provide information that can influence health care and public health policy decisions. To date, however, there has been no report, to our knowledge, of longitudinal trends in national laboratory test use.

OBJECTIVE

To evaluate Medicare Part B-reimbursed volumes of selected laboratory tests per 10,000 enrollees from 2000 through 2010.

DESIGN

Laboratory test reimbursement volumes per 10,000 enrollees in Medicare Part B were obtained from the Centers for Medicare & Medicaid Services (Baltimore, Maryland). The ratio of the most recent (2010) reimbursed test volume per 10,000 Medicare enrollees, divided by the oldest data (usually 2000) during this decade, called the volume ratio, was used to measure trends in test reimbursement. Laboratory tests with a reimbursement claim frequency of at least 10 per 10,000 Medicare enrollees in 2010 were selected, provided there was more than a 50% change in test reimbursement volume during the 2000-2010 decade. We combined the reimbursed test volumes for the few tests that were listed under more than one code in the Current Procedural Terminology (American Medical Association, Chicago, Illinois). A 2-sided Poisson regression, adjusted for potential overdispersion, was used to determine P values for the trend; trends were considered significant at P < .05.

RESULTS

Tests with the greatest decrease in reimbursement volumes were electrolytes, digoxin, carbamazepine, phenytoin, and lithium, with volume ratios ranging from 0.27 to 0.64 (P < .001). Tests with the greatest increase in reimbursement volumes were meprobamate, opiates, methadone, phencyclidine, amphetamines, cocaine, and vitamin D, with volume ratios ranging from 83 to 1510 (P < .001).

CONCLUSIONS

Although reimbursement volumes increased for most of the selected tests, other tests exhibited statistically significant downward trends in annual reimbursement volumes. The observed changes in reimbursement volumes may be explained by disease prevalence and severity, patterns of drug use, clinical or laboratory practices, and testing recommendations and guidelines, among others. These data may be useful to policy makers, health systems researchers, laboratory directors, and industry scientists to understand, address, and anticipate trends in laboratory testing in the Medicare population.

Phase I study of PM00104 (Zalypsis®) administered as a 1-hour weekly infusion resting every fourth week in patients with advanced solid tumors

PM00104 (Zalypsis®) is a new synthetic alkaloid with potent cytotoxic activity against tumor cell lines. This phase I clinical trial determined the maximal tolerated dose (MTD) and recommended dose (RD) for phase II trials of PM00104 administered as a 1-hour intravenous (i.v.) infusion weekly for three consecutive weeks resting every fourth week (d1,8,15 q4wk). Forty-nine patients with advanced solid malignancies received PM00104 following a toxicity-guided, accelerated, dose-escalation design. Doses evaluated ranged from 0.07 to 3.0 mg/m(2). Dose-limiting toxicities (DLTs) appeared at the highest doses tested and comprised grade 3 diarrhea and grade 4 lipase increase at 2.0 mg/m(2); grade 1 thrombocytopenia and grade 2 neutropenia with two infusion omissions, grade 3 fatigue and grade 4 febrile neutropenia at 2.5 mg/m(2); and grade 3/4 fatigue, grade 4 neutropenia lasting >5 days and grade 4 thrombocytopenia at 3.0 mg/m(2). RD was established at 2.0 mg/m(2). PM00104-related adverse events at the RD were mostly grade 1/2, with fatigue, nausea and vomiting as the most common. Transient and manageable myelosuppression and transaminase increases were also reported. Main pharmacokinetic parameters increased linearly with dose. Disease stabilization lasting ≥ 3 months was found in 4 patients with cervical carcinoma, colorectal adenocarcinoma, lachrymal adenoid carcinoma, and bladder carcinoma (n=1 each). In conclusion, PM00104 2.0 mg/m(2) 1-hour, d1,8,15 q4wk showed a positive risk-benefit ratio, which has supported its further evaluation in three ongoing phase II clinical trials.

Clinical Use and Measurement of Cardiac Troponin (cTn)

Cardiac troponins are cardio-specific and are widely used for the early diagnosis and triage of patients with acute coronary syndromes in conjunction with clinical history, electrocardiographic changes and imaging. Troponin is also useful for the prediction of outcomes in acute coronary syndromes, renal failure, sepsis, and critically ill patients. New developments in assay technology, designated as high sensitivity troponins, permit detection of lower levels of troponin in most healthy individuals, earlier diagnosis of myocardial infarction, and prognosis of stable coronary disease in the community.