Laboratory diagnosis of patients with acute chest pain

Clinical Analysis of Myocardial Injury in Highlanders with Pulmonary Hypertension

Background: Pulmonary hypertension (PH) is a prevalent adverse cardiovascular event at high-altitude environments. Prolonged exposure to high altitudes may result in myocardial injury, which is associated with poor clinical outcomes. This study aims to investigate the clinical characteristics of myocardial injury in patients with PH at high altitude. Methods: Consecutive patients admitted to a general tertiary hospital at the altitude of 3,650 m were selected into this retrospective study. Clinical and biochemical data were collected, as well as based on cardiac troponin I (cTnI) and echocardiography, patients were divided into myocardial injury group and non-myocardial injury group. Results: A total of 231 patients were enrolled, among whom 29 (12.6%) had myocardial injury. We found that body mass index, left ventricular end-diastolic dimension, and serum level of creatine kinase-MB (CK-MB) in myocardial injury group were significantly higher than non-myocardial injury group. Spearman correlation analysis revealed that cTnI has a significant positive correlation with CK-MB and lactic dehydrogenase instead of aspartate aminotransferase. A receiver operating characteristic curve was drawn to demonstrate that CK-MB could significantly predict the occurrence of myocardial injury with an area under the curve of 0.749, and a level of 3.035 (sensitivity = 59.3%, specificity = 90.5%) was optimal cutoff value. Conclusion: The incidence of myocardial injury in highlanders with PH is significant. CK-MB, as a convenient and efficient marker, has been found to be closely associated with cTnI and plays a predictive role in the occurrence of myocardial injury with PH in individuals exposed to high altitude.

Elevated Cardiac Troponin I following Asymptomatic Intradialytic Hypotension: A Pilot Study with a 2-Year Follow-Up

Background

Intradialytic hypotension (IDH) has been recognized as a serious and frequent complication during hemodialysis (HD) of end-stage renal disease (ESRD) patients, but the effect of asymptomatic IDH on cardiac troponin I (cTnI) levels is not definitively elucidated.

Methods

70 asymptomatic HD patients with negative predialysis cTnI were included. They were on maintenance HD thrice weekly. All patients were monitored during the HD session for hemodynamic changes and symptoms related to IDH. Patients were followed for two years, and their outcomes are noted as an acute coronary syndrome (ACS), cardiac death, no ACS, noncardiac death, and kidney transplant.

Results

Compared with the baseline blood pressure values, there was a drop in systolic blood pressure for all subjects, but according to the 2007 European Best Practice Guidelines on hemodynamic instability, asymptomatic IDH was defined in 27 (38.6%) patients. The results demonstrated a significant correlation (r = 0.492) (p < 0.05) between asymptomatic IDH and elevated postdialysis levels of cTnI. In 2-year follow-up of patients, ACS and cardiac death happened more in patients with elevated cTnI.

Conclusion

The results of our study suggest that asymptomatic IDH affects cTnI levels. Given that cTnI is a marker of myocardial damage and a predictor of cardiovascular mortality in ESRD patients, these findings recommend that considering the asymptomatic decrease in blood pressure levels during HD is very important and critical.

A machine learning model to predict critical care outcomes in patient with chest pain visiting the emergency department

Background

Currently, the risk stratification of critically ill patient with chest pain is a challenge. We aimed to use machine learning approach to predict the critical care outcomes in patients with chest pain, and simultaneously compare its performance with HEART, GRACE, and TIMI scores.

Methods

This was a retrospective, case-control study in patients with acute non-traumatic chest pain who presented to the emergency department (ED) between January 2017 and December 2019. The outcomes included cardiac arrest, transfer to ICU, and death during treatment in ED. In the randomly sampled training set (70%), a LASSO regression model was developed, and presented with nomogram. The performance was measured in both training set (70% participants) and testing set (30% participants), and findings were compared with the three widely used scores.

Results

We proposed a LASSO regression model incorporating mode of arrival, reperfusion therapy, Killip class, systolic BP, serum creatinine, creatine kinase-MB, and brain natriuretic peptide as independent predictors of critical care outcomes in patients with chest pain. Our model significantly outperformed the HEART, GRACE, TIMI score with AUC of 0.953 (95%CI: 0.922–0.984), 0.754 (95%CI: 0.675–0.832), 0.747 (95%CI: 0.664–0.829), 0.735 (95%CI: 0.655–0.815), respectively. Consistently, our model demonstrated better outcomes regarding the metrics of accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score. Similarly, the decision curve analysis elucidated a greater net benefit of our model over the full ranges of clinical thresholds.

Conclusion

We present an accurate model for predicting the critical care outcomes in patients with chest pain, and provide substantial support to its application as a decision-making tool in ED.

Effect and Mechanism of Ganoderma lucidum Spores on Alleviation of Diabetic Cardiomyopathy in a Pilot in vivo Study

BACKGROUND

Ganoderma lucidum spores (GLS) exhibit disease prevention properties, but no study has been carried out on the anti-diabetic cardiomyopathy property of GLS. The aim of this study was to evaluate the hyperglycemia-mediated cardiomyopathy protection and mechanisms of GLS in streptozotocin (STZ)induced diabetic rats.

METHODS

Male SD rats were randomly divided into three groups. Two groups were given STZ (50 mg/kg, i.p.) treatment and when their fasting plasma glucose was above 16.7 mmol/L, among them, one group was given placebo, as diabetic group, and another group was given GLS (300 mg/kg) treatment. The group without STZ treatment was given placebo as a control group. The experiment lasted 70 days. The histology of myocardium and biomarkers of antioxidants, myocardial injury, pro-inflammatory cytokines, pro-apoptotic proteins and phosphorylation of key proteins in PI3K/AKT pathway were assessed.

RESULTS

Biochemical analysis showed that GLS treatment significantly reduced the blood glucose (-20.3%) and triglyceride (-20.4%) levels compared to diabetic group without treatment. GLS treatment decreased the content of MDA (-25.6%) and activity of lactate dehydrogenase (-18.9%) but increased the activity of GSH-Px (65.4%). Western blot analysis showed that GLS treatment reduced the expression of both alpha-smooth muscle actin and brain natriuretic peptide. Histological analysis on the cardiac tissue micrographs showed that GLS treatment reduced collagen fibrosis and glycogen reactivity in myocardium. Both Western blot and immunohistochemistry analyses showed that GLS treatment decreased the expression levels of pro-inflammatory factors (cytokines IL-1β, and TNF-α) as well as apoptosis regulatory proteins (Bax, caspase-3 and -9), but increased Bcl-2. Moreover, GLS treatment significantly increased the phosphorylation of key proteins involved in PI3K/AKT pathway, eg, p-AKT p-PI3K and mTOR.

CONCLUSION

The results indicated that GLS treatment alleviates diabetic cardiomyopathy by reducing hyperglycemia, oxidative stress, inflammation, apoptosis and further attenuating the fibrosis and myocardial dysfunction induced by STZ through stimulation of the PI3K/Akt/mTOR signaling pathway.

Valid cardiac biomarkers. Part I

Biomarkers are widely used for the diagnosing of diseases, evaluation of their severity, prediction of outcomes, and for monitoring the effectiveness and safety of targeted therapy. This review describes specific cardiac biomarkers approved by FDA (Food and Drug AdministrationбUSA). The list of described biomarkers is not exhaustive. In addition to the general concepts of biomarkers, definitions and classification, this Part I of the review contains data on diagnostic and prognostic biomarkers of cardiovascular diseases associated with atherosclerosis.

Comparative evaluation of 15-minute rapid diagnosis of ischemic heart disease by high-sensitivity quantification of cardiac biomarkers

A rapid clinical diagnosis may efficiently improve the survival rate and prognosis of patients with ischemic heart disease (IHD). Therefore, a one-step, rapid and inexpensive analysis for the quick diagnosis of IHD was investigated in the present study. Consecutive patients who were subjected to myoglobin, cardiac troponin I and creatine kinase-MB isoenzyme assessment at the Emergency Department of Shenzhen Second People's Hospital (Shenzhen, China) between December 2017 and March 2018 prior to treatment were screened. Clinically applicable disposable strips were employed for quantification of the cardiac biomarkers. The analytical performance of the strips was evaluated by receiver operating characteristic (ROC) curves and compared with the traditional chemiluminescence immunoassay (CLIA) method. The data of 391 participants were collected. At the baseline, 57 patients were diagnosed with IHD and 334 patients were diagnosed with other diseases. The area under the ROC curve (AUC) of the CLIA model was 0.787 (95% CI, 0.709-0.865) with a specificity of 76.7% and a sensitivity of 71.9%. At the optimal cutoff value of -1.867, the negative and the positive predictive value were 94.1 and 34.5%, respectively. The AUC of the disposable strip model was 0.792 (95% CI, 0.729-0.855). At the cutoff value of -1.820 or below, the negative predictive value was 94.9%, the positive predictive value was 28.9%, the specificity was 66.8% and the sensitivity was 79.0%. The P-value of the ROCs was 0.858, indicating no statistically significant difference between the two assay methods. The cost of the disposable strip was 50% of that of the CLIA method and it took only 25% of the time that was required for the quantification of the three cardiac markers by CLIA. In conclusion, the disposable strip provides a platform for point-of-care testing and may be an easy, rapid, reliable and cost-saving method for the diagnosis of IHD.

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.

Quantification of intramyocardial hemorrhage volume using magnetic resonance imaging with three-dimensional T1-weighted sequence in patients with ischemia-reperfusion injury: a semi-automated image processing technique

Although intramyocardial hemorrhage (IMH) is a poor prognostic factor caused by ischemia reperfusion injury, little evidence is available regarding the association between IMH volume and biomarkers. In the present study, we measured IMH volume using three-dimensional (3D) T1-weighted magnetic resonance imaging (T1-MRI) and investigated its association with biomarkers. Moreover, the accuracy of semi-automatic measurement of IMH volume was validated. We retrospectively enrolled 33 consecutive patients (mean age 67 ± 11 years) who underwent cardiac MRI after reperfusion therapy for acute myocardial infarction. IMH was observed in 4 patients (12.1%). Receiver operating characteristics (ROC) analysis of creatine kinase (CK) and CK-muscle/brain (CK-MB) tests for detecting IMH were performed. IMH volume measured using semi-automatic methods by a 2 standard deviation (SD) threshold was compared to manual measurements using the Spearman's correlation coefficient (ρ) and Bland-Altman analyses. ROC analysis revealed optimal cutoff values of CK: 2460 IU/l and CK-MB: 231 IU/l (area under the curve: 0.95 and 0.91; sensitivity: 86% and 79%; specificity: 100% for both). IMH volume with the 2SD threshold correlated with that of the manual measurement [5.84 g (3.30 to 9.00) g vs. 8.07 g (5.37 to 9.33); ρ: 0.85, p < 0.01; bias (limit of agreement): - 0.01 g (- 0.51 to 0.49); intraclass correlation coefficients 0.84 (0.75 to 0.90)]. Our findings could help identify the risk of IMH after reperfusion therapy with biomarkers. 3D T1-MRI can semi-automatically provide accurate IMH volume without being time-consuming.

Clinical utility of mean platelet volume and immature platelet fraction in acute coronary syndrome

Background

Platelets play an important role in the pathogenesis of acute coronary syndrome (ACS). Patients with ACS have an increased mean platelet volume (MPV) and immature platelet fraction (IPF) resulting in elevation of thrombotic ability. In this study, we evaluated the diagnostic performance of MPV and IPF in identifying suspected ACS patients at emergency department. Moreover, we investigated the correlation between MPV or IPF with initial troponin I (TnI), one of the current ACS biomarkers.

Methods

This was a single-center study recruiting suspected ACS patients who had acute chest pain at the emergency department. Whole blood samples were obtained from all participants and MPV and IPF were measured by Sysmex XE-5000 hematology analyzer within 20 min of blood sampling. The diagnostic values of MPV and IPF in identifying ACS were analyzed retrospectively.

Result

In this study, 63 in 104 suspected ACS patients were diagnosed as ACS (65.3%). MPV and IPF were higher in ACS patients compared to non-ACS patients (MPV: 10.7 ± 0.80 fL vs 10.0 ± 0.64 fL, p < 0.001; IPF: 3.7 ± 2.64% vs 3.1 ± 2.69%, p = 0.030). MPV and IPF were similar in unstable angina and acute myocardial infarction patients. We showed that elevation of MPV could be an independent predictive factor of ACS (odds ratio: 5.038). At the optimal cut-off value of 10.55 fL (AUC 95% CI: 0.637–0.836), the diagnostic performance of MPV in predicting ACS had an area under a receiver operating characteristic curve (AUC) of 0.736 with sensitivity and specificity of 54.2% and 82.8%, respectively. Patients with both of initial TnI and MPV higher than the established cut-off value had increased incidence (3.792 fold) for ACS development compared to patients with TnI below the cut-off value. Furthermore, diagnosing ACS with both MPV and initial TnI increased the positive predictive value from 84.2% to 86.7%. No correlation was observed between MPV or IPF and the mortality rate of ACS patients (MPV: 3.8% vs 11.1%, p = 0.300; IPF: 12.0% vs 37.5%, p = 0.054).

Conclusion

Here we show that ACS patients have higher MPV and IPF compared to non-ACS patients. We further demonstrate that MPV can be utilized as an independent predictor for early diagnosis of low-risk ACS patients who have acute chest pain.

Electrochemical cardiovascular platforms: Current state of the art and beyond

Cardiovascular diseases (CVD) remain the leading cause of death within industrialized nations as well as an increasing cause of mortality and morbidity in many developing countries. Smoking, alcohol consumption and increased level of blood cholesterol are the main CVD risk factors. Other factors, such as the prevalence of overweight/obesity and diabetes, have increased considerably in recent decades and are indirect causes of CVD. Among CVDs, the acute coronary syndrome (ACS) represents the most common cause of emergency hospital admission. Since the prognosis of ACS is directly associated with timely initiation of revascularization, missed, misdiagnosis or late diagnosis have unfavorable medical implications. Early ACS diagnosis can reduce complications and risk of recurrence, finally decreasing the economic burden posed on the health care system as a whole. To decrease the risk of ACS and related CVDs and to reduce associated costs to healthcare systems, a fast management of patients with chest pain has become crucial and urgent. Despite great efforts, biochemical diagnostic approaches of CVDs remain difficult and controversial medical challenges as cardiac biomarkers should be rapidly released into the blood at the time of ischemia and persistent for a sufficient length of time to allow diagnostics, with tests that should be rapid, easy to perform and relatively inexpensive. Early biomarker assessments have involved testing for the total enzyme activity of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK), which cardiac troponins being the main accepted biomarkers for diagnosing myocardial injury and acute myocardial infarction (AMI). To allow rapid diagnosis, it is necessary to replace the traditional biochemical assays by cardiac biosensor platforms. Among the numerous of possibilities existing today, electrochemical biosensors are important players as they have many of the required characteristics for point-of-care tests. Electrochemical based cardiac biosensors are highly adapted for monitoring the onset and progress of cardiovascular diseases in a fast and accurate manner, while being cheap and scalable devices. This review outlines the state of the art in the development of cardiac electrochemical sensors for the detection of different cardiac biomarkers ranging from troponin to BNP, N-terminal proBNP, and others.

Tramadol-induced hepato- and nephrotoxicity in rats: Role of Curcumin and Gallic acid as antioxidants

Tramadol is an analgesic used to treat moderate to severe pain caused by cancer, osteoarthritis, and other musculoskeletal diseases. Cytochrome P450 system metabolizes tramadol and induces oxidative stress in different organs. Therefore, the present study aims at investigating the changes in the activities and the protein expressions of CYPs isozymes (2E1, 3A4, 2B1/2), antioxidants status, free radicals levels after pretreatment of rats with Curcumin and/or Gallic as single- and/or repeated-doses before administration of tramadol. In repeated-dose treatments of rats with tramadol, the activities of cytochrome P450, cytochrome b5, and NADPH-cytochrome-c-reductase, and the antioxidant enzymes including glutathione reductase, glutathione peroxidase, glutathione S-transferase, catalase, superoxide dismutase, and levels of glutathione were inhibited in the liver and the kidney of rats. Interestingly, such changes caused by tramadol restored to their normal levels after pretreatment of rats with either Curcumin and/or Gallic acid. On the other hand, repeated-dose treatment of rats with tramadol increased the activities of both dimethylnitrosamine N-demethylase I (DMN-dI), and aryl hydrocarbon hydroxylase (AHH) compared to the control group. However, pretreatment of rats with Curcumin and/or Gallic acid prior to administration of tramadol restored the inhibited DMN-dI activity and its protein expression (CYP 2E1) to their normal levels. On the other hand, tramadol inhibited the activity of ethoxycoumarin O-deethylase (ECOD) and suppressed its protein marker expression (CYP2B1/2), whereas Curcumin, Gallic acid and/or their mixture restored such changes to their normal levels. In conclusion, Curcumin and/or Gallic acid alleviated the adverse effects caused by tramadol. In addition, patients should be advice to take Curcumin and/or Gallic acid prior to tramadol treatment to alleviate the hepatic and renal toxicities caused by tramadol.

The (Dis) Utility of a Change in Troponin I for Diagnosis of Non-ST-Segment Elevation Myocardial Infarction in an Observation Unit

BACKGROUND

Observation units (OUs) may be an efficient and effective setting to diagnose and risk stratify patients with coronary ischemia and myocardial infarction (MI). Given improved cardiac troponin I (cTnI) assays and expanded utilization of OUs, it is not uncommon for patients with mildly elevated cTnI to be evaluated in OUs. We investigated the serial cTnI results in OU patients to determine whether absolute or relative cTnI changes were useful for the diagnosis of MI.

METHODS

This was a retrospective study of 260 patients placed in the OU from a single center in 2007, with an initial cTnI in the indeterminate range of 0.04-0.2 ng/ml (Siemens ultrasensitive), and a second cTnI was drawn at 6 hours. The diagnosis of MI was determined based on the third universal definition of MI by consensus review of 2 cardiologists, with adjudication by a third cardiologist in case of disagreement.

RESULTS

Of the 260 patients, 25 (9.6%) were determined to have MI at OU presentation. The optimal absolute and relative change in cTnI for MI diagnosis by receiver operating characteristic curve analysis were 0.02 ng/ml and 40%, respectively. There was initial cardiologist disagreement in 60% (15/25) of MI cases despite full review of serial cTnI and cardiac testing results. At 30 days, there were 3 adverse events: 2 deaths and 1 MI.

CONCLUSIONS

The diagnosis of MI in OU with low-level cTnI elevation is problematic. Furthermore, there is only marginal diagnostic utility of serial changes in cTnI in this patient population.

Kinetics of plasma von Willebrand factor in acute myocardial infarction patients: a meta-analysis

Previous studies have shown a variation in plasma level of von Willebrand factor (vWF) in acute myocardial infarction (AMI) patients but with contentious results. In this study, we performed a meta-analysis to evaluate the kinetics of plasma vWF after AMI. A total of 11 qualified studies were obtained through systematical search in PubMed, Web of science, Cochrane Library database and CNKI, followed by search of reference lists, involving 519 AMI patients and 466 non-AMI controls. The standard mean difference (SMD) and 95% confidence intervals (95% CI) were calculated using random-effects model. Results indicated that the plasma vWF was significantly increased in the first several hours after onset of AMI (SMD = 1.94, 95% CI = 1.39-2.48, P < 0.001) and stayed at high level until 24 h (SMD = 1.17, 95% CI = 0.45-1.89, P = 0.001). Elevated level of vWF appeared to persist for one week and reduced to normal until the fourteenth day after AMI (SMD = 0.44, 95% CI = -0.14-1.02, P = 0.14). Subgroup analysis revealed that the high level of vWF lasted just for 1 day in patients with a symptom duration ≤ 6 h before admission. For patients with a symptom duration > 6 h, elevated vWF was found in all 7 days except day 1. Our findings determined the kinetics of plasma vWF after AMI, and might provide a new insight in monitoring AMI progression.

How Well Do Laboratories Adhere to Recommended Clinical Guidelines for the Management of Myocardial Infarction: The CARdiac MArker Guidelines Uptake in Europe Study (CARMAGUE)

BACKGROUND

We undertook an assessment of current use of evidence-based guidelines for the use of cardiac biomarkers in Europe (EU) and North America (NA).

METHODS

In 2013–2014 a web-based questionnaire was distributed via NA and EU biochemical societies. Questions covered cardiac biomarkers measured, analytical methods used, decision thresholds, and use of decision-making protocols. Results were collated using a central database and analyzed using comparative and descriptive nonparametric statistics.

RESULTS

In EU, returns were obtained from 442 hospitals, 50% central or university hospitals, and 39% from local hospitals from 35 countries with 395/442 (89%) provided an acute service. In NA there were 91 responses (63.7% central or university hospitals, 19.8% community hospitals) with 76/91 (83.5%) providing an acute service. Cardiac troponin was the preferred cardiac biomarker in 99.5% (EU) and 98.7% (NA), and the first line marker in 97.7% (EU) and 97.4% (NA). There were important differences in the choice of decision limits and their derivations. The origin of the information was also significantly different, with EU vs NA as follows: package insert, 61.9% vs 40%; publications, 17.1% vs 15.0%; local clinical or analytical validation choice, 21.0% vs 45.0%; P = 0.0003.

CONCLUSIONS

There are significant differences between EU and NA use of cardiac biomarkers. This probably relates to different availability of assays between EU and NA (such as high-sensitivity troponin assays) and different laboratory practices on assay introduction (greater local evaluation of assay performance occurred in NA).

An historical approach to the diagnostic biomarkers of acute coronary syndrome

Suspected acute myocardial infarction (AMI) is one of the leading causes of admission to the emergency departments in Western countries but also an increasing cause in many other nations. The diagnosis of AMI involves the evaluation of clinical signs and symptoms, electrocardiographic assessment, and measurement of cardiac circulating biomarkers. In the last sixty years, the use of laboratory markers has changed considerably. Early biomarkers assessment has entailed testing for total enzyme activity of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK). Advances in electrophoresis allowed the identification of more cardio-specific isoenzymes of both CK and LDH, thus leading to the introduction of the CK-MB and LDH-1 activity assays. Soon thereafter, the development of immunoassays, as well as technical advances in automation, allowed the measurements of the CK-MB in mass rather than in activity and myoglobin. Currently, cardiac troponins have the highest sensitivity and specificity for myocardial necrosis and represent the biochemical gold standard for diagnosing AMI. This review provides a chronology of the major events which marked the evolution of cardiac biomarkers testing and the development of the relative assays from the first introduction of AST in the 1950s to the last high sensitivity troponin immunoassays in the 2010s.

Plasma nuclear and mitochondrial DNA levels in acute myocardial infarction patients

Objective

Plasma nuclear and mitochondrial DNA (mtDNA) levels are altered in many diseases. However, it is not known whether they are also altered in acute myocardial infarction (AMI). In the present study, we examined plasma nuclear and mtDNA levels in the patients with AMI before and after a percutaneous coronary intervention (PCI) to explore their potential as biomarkers.

Methods and results

Plasma nuclear and mtDNA levels were measured by quantitative PCR in 25 AMI patients, 25 non-myocardial infarction (MI) control participants (with MI risk), and 20 healthy individuals during the study period. The concentrations of nuclear and mtDNA were significantly higher in the AMI group on hospital day 1 than that in the non-MI controls (nuclear: 0.4948±0.0830 vs. 0.2047±0.0222 ng/μl, P<0.05; mitochondrial: 3.754±0.384 vs. 1.851±0.3483 ng/μl, P<0.05) and healthy individuals (nuclear: 0.4948±0.0830 vs. 0.1683±0.0254 ng/μl, P=0.001; mitochondrial: 3.754±0.384 vs. 0.1517±0.0924 ng/μl, P<0.05) and decreased shortly after PCI.

Conclusion

Both plasma nuclear and mtDNA levels are elevated in AMI patients, but return to normal levels immediately after PCI, suggesting that they are potentially novel biomarkers for AMI.

Plasma Lactate Dehydrogenase Levels Predict Mortality in Acute Aortic Syndromes: A Diagnostic Accuracy and Observational Outcome Study

In acute aortic syndromes (AAS), organ malperfusion represents a key event impacting both on diagnosis and outcome. Increased levels of plasma lactate dehydrogenase (LDH), a biomarker of malperfusion, have been reported in AAS, but the performance of LDH for the diagnosis of AAS and the relation of LDH with outcome in AAS have not been evaluated so far.This was a bi-centric prospective diagnostic accuracy study and a cohort outcome study. From 2008 to 2014, patients from 2 Emergency Departments suspected of having AAS underwent LDH assay at presentation. A final diagnosis was obtained by aortic imaging. Patients diagnosed with AAS were followed-up for in-hospital mortality.One thousand five hundred seventy-eight consecutive patients were clinically eligible, and 999 patients were included in the study. The final diagnosis was AAS in 201 (20.1%) patients. Median LDH was 424 U/L (interquartile range [IQR] 367-557) in patients with AAS and 383 U/L (IQR 331-460) in patients with alternative diagnoses (P < 0.001). Using a cutoff of 450 U/L, the sensitivity of LDH for AAS was 44% (95% confidence interval [CI] 37-51) and the specificity was 73% (95% CI 69-76). Overall in-hospital mortality for AAS was 23.8%. Mortality was 32.6% in patients with LDH ≥ 450 U/L and 16.8% in patients with LDH < 450 U/L (P = 0.006). Following stratification according to LDH quartiles, in-hospital mortality was 12% in the first (lowest) quartile, 18.4% in the second quartile, 23.5% in the third quartile, and 38% in the fourth (highest) quartile (P = 0.01). LDH ≥ 450 U/L was further identified as an independent predictor of death in AAS both in univariate and in stepwise logistic regression analyses (odds ratio 2.28, 95% CI 1.11-4.66; P = 0.025), in addition to well-established risk markers such as advanced age and hypotension. Subgroup analysis showed excess mortality in association with LDH ≥ 450 U/L in elderly, hemodynamically stable and in nonsurgically treated patients.Plasma LDH constitutes a biomarker of poor outcome in patients with AAS. LDH is a rapid and universally available assay that could be used to improve risk stratification and to individualize treatment in patient groups where options are controversial.

Cardiac troponin I as compared to troponin T for the detection of myocardial damage in horses

BACKGROUND

Different cardiac troponin I (cTnI) assays give different results. Only 1 manufacturer has marketed troponin T (cTnT) assays. Therefore, cTnT often is preferred for detection of myocardial infarction in human patients. Studies of cTnT in horses are limited.

OBJECTIVES

To compare a cTnI and a high-sensitive cTnT assay (hs-cTnT) in horses.

ANIMALS

Cardiac troponin I and cTnT were determined in 35 healthy horses (group 1), 23 horses suspected to have primary myocardial damage (group 2a), and 41 horses with secondary myocardial damage caused by structural heart disease (group 2b).

METHODS

All cTnI samples were analyzed at laboratory A (limit of detection [LOD]: 0.03 ng/mL), whereas cTnT samples were analyzed at 2 laboratories with the same hs-cTnT assay (laboratory B, LOD: 10.0 pg/mL; laboratory C, LOD: 4.0 pg/mL).

RESULTS

The median cTnI concentration in group 2a (0.90 ng/mL; range, 0.03-58.27 ng/mL) was significantly higher (P < .001) than in group 1 (0.03 ng/mL; range, 0.03-0.09 ng/mL) or group 2b (0.05 ng/mL; range, 0.03-30.92 ng/mL), and the optimal cut-off for detection of primary myocardial damage was 0.095 ng/mL (sensitivity: 90.5%, specificity: 100%). Using an LOD of 10.0 pg/mL for all cTnT samples, a cut-off value of 10.5 pg/mL was found, but sensitivity was low (42.9%). When only samples analyzed at laboratory C (n = 58) were included, a cut-off of 6.6 pg/mL was found (sensitivity: 81%, specificity: 100%).

CONCLUSIONS AND CLINICAL IMPORTANCE

Despite large quantitative differences, cTnI and cTnT are both useful for detection of myocardial damage in horses.

Perspectives on the value of biomarkers in acute cardiac care and implications for strategic management

Biomarkers in acute cardiac care are gaining increasing interest given their clinical benefits. This study is a review of the major conditions in acute cardiac care, with a focus on biomarkers for diagnostic and prognostic assessment. Through a PubMed search, 110 relevant articles were selected. The most commonly used cardiac biomarkers (cardiac troponin, natriuretic peptides, and C-reactive protein) are presented first, followed by a description of variable acute cardiac conditions with their relevant biomarkers. In addition to the conventional use of natriuretic peptides, cardiac troponin, and C-reactive protein, other biomarkers are outlined in variable critical conditions that may be related to acute cardiac illness. These include ST2 and chromogranin A in acute dyspnea and acute heart failure, matrix metalloproteinase in acute chest pain, heart-type fatty acid binding protein in acute coronary syndrome, CD40 ligand and interleukin-6 in acute myocardial infarction, blood ammonia and lactate in cardiac arrest, as well as tumor necrosis factor-alpha in atrial fibrillation. Endothelial dysfunction, oxidative stress and inflammation are involved in the physiopathology of most cardiac diseases, whether acute or chronic. In summary, natriuretic peptides, cardiac troponin, C-reactive protein are currently the most relevant biomarkers in acute cardiac care. Point-of-care testing and multi-markers use are essential for prompt diagnostic approach and tailored strategic management.

Label-free microcavity biosensors: steps towards personalized medicine

Personalized medicine has the potential to improve our ability to maintain health and treat disease, while ameliorating continuously rising healthcare costs. Translation of basic research findings to clinical applications within regulatory compliance is required for personalized medicine to become the new foundation for practice of medicine. Deploying even a few of the thousands of potential diagnostic biomarkers identified each year as part of personalized treatment workflows requires clinically efficient biosensor technologies to monitor multiple biomarkers in patients in real time. This paper discusses a critical component of a regulatory system, a microcavity optical biosensor for label-free monitoring of biomolecular interactions at physiologically-relevant concentrations. While most current biosensor research focuses on improving sensitivity, this paper emphasizes other characteristics a biosensor technology requires to be practical in a clinical setting, presenting robust microcavity biosensors which are easy to manufacture and integrate with microfluidics into flexible and redesignable platforms making the microcavity biosensors deployable for continuous monitoring of biomarkers in body fluids in the clinic, in dense 2D random arrays for high-throughput applications like drug-library screening in interactomics, and of the secretory behavior of single cells in the laboratory.

Repetitive low-volume blood sampling method as a feasible monitoring tool in a mouse model of sepsis

Blood-based monitoring of immunoinflammatory and organ function fluctuations is essential in models of critical illness. This is challenging in diseased mice as repetitive blood collection may be harmful and/or affect end points. We studied the influence of daily sampling in acutely septic (days 1-5) mice upon survival and selected hematologic and organ function parameters. In addition, we tested the reliabilty of complete blood cell (CBC) count using resuspended blood cells. Female OF-1 and CD-1 mice underwent cecal ligation and puncture (CLP) and were subdivided into Daily and Day 5 groups. Blood was collected daily for 5 days in the Daily group and only on day 5 post-CLP in the Day 5 group. We tested 20 μL (both strains) and 35 μL (OF-1 mice) sampling volumes. The 35-μL volume simultaneously served to test the CBC reliabilty in resuspended versus unprocessed blood. Daily sampling did not affect the 14-day CLP mortality. Compared with the Day 5 group, daily 35-μL sampling in OF-1 mice decreased the red blood cell count and hemoglobin concentration by 22% and 23% (P < 0.05). In neither strain did daily 20-μL sampling affect the red blood cell count, whereas there was a 9% hemoglobin decrease (P < 0.05) in OF-1 mice. Although alanine aminotransferase, lactate dehydrogenase, and glucose levels were comparable, urea significantly increased by 24% in the Daily group (20-μL volume, OF-1 mice). Interleukin 6, platelets, and white blood cell counts remained unaffected. There was an excellent correlation between regular and resuspended CBC for all cell types (r ≥ 0.9; slope, ≥0.9), except lymphocytes (r > 0.5; slope, >0.5). This method provides a feasible and safe translation of clinically relevant daily immunomonitoring to the mouse sepsis model.

Sepsis biomarkers: a review

INTRODUCTION

Biomarkers can be useful for identifying or ruling out sepsis, identifying patients who may benefit from specific therapies or assessing the response to therapy.

METHODS

We used an electronic search of the PubMed database using the key words "sepsis" and "biomarker" to identify clinical and experimental studies which evaluated a biomarker in sepsis.

RESULTS

The search retrieved 3370 references covering 178 different biomarkers.

CONCLUSIONS

Many biomarkers have been evaluated for use in sepsis. Most of the biomarkers had been tested clinically, primarily as prognostic markers in sepsis; relatively few have been used for diagnosis. None has sufficient specificity or sensitivity to be routinely employed in clinical practice. PCT and CRP have been most widely used, but even these have limited ability to distinguish sepsis from other inflammatory conditions or to predict outcome.

Imprecision of cardiac marker analyses among laboratories on the basis of external quality assurance results: Finnish experience

The purpose of this report was to evaluate the reproducibility and harmonization of cardiac marker tests and to describe the current situation concerning quality of assays for cardiac markers on the basis of the results of the external quality control schemes (EQAS) of Labquality Ltd., Helsinki, Finland in the period 2002 to 2005. Finnish EQAS surveys obtained for proficiency samples at low marker concentration indicated that the overall coefficient of variation (CV) between laboratories for CK-MBmass and troponin I exceeded 10 %, while for cardiac troponin T the CV was 8.6 %. Intra-laboratory reproducibility was investigated in a single laboratory using concomitant testing in the same EDTA plasma samples to establish cut-off limits for one CK-MBmass and three troponin assays. The 10 % imprecision limit obtained from the concomitant testing in the same samples for CK-MBmass was (by Elecsys) 8.5 microg/L, for cardiac troponin T (by Elecsys) 0.023 microg/L and for cardiac troponin I (by AxSYM) and by Immulite 2000) 0.85 microg/L and 0.63 microg/L. At present, it is recommended that laboratories determine the concentration at which the 10 % imprecision for a specific cardiac marker assay is reached, because the assays generally do not reach that imprecision at the level of the 99th percentile value, usually taken as decisional level. However, common efforts of scientific societies and professional diagnostic industry associations internationally are needed if consensus is to be reached on standardization of immunoassays for cardiac markers and uniform results obtained among laboratories.

Effect of hemodialysis on traditional and innovative cardiac markers

The diagnostic approach to acute coronary syndrome (ACS) is challenging in patients with impaired renal function since most serum biomarkers are commonly increased in this clinical setting. Cardiac troponin T (cTnT), creatine kinase isoenzyme MB (CK MB), myoglobin, and ischemia modified albumin (IMA), were assayed in 45 patients prehemodialysis (pre-HD) and posthemodialysis (post-HD), and results were adjusted for hemoconcentration. The pre-HD values of serum IMA and cTnT were above the respective diagnostic thresholds (IMA<85 K units/L; cTnT <0.03 ng/mL) in six (13%) and 27 (60%) patients undergoing chronic HD, respectively. A significant (105.0 vs. 79.0 K units/L, P<0.0001) and variable (+38%; 95% confidence interval [CI], 12-65%) increase of serum IMA was observed post-HD, whereas the other biomarkers significantly decreased (cTnT: 0.029 vs. 0.044 ng/mL, P=0.016; CK-MB: 2.33 vs. 2.50 microg/L, P<0.0001; myoglobin: 128.1 vs. 148.7 microg/L, P<0.0001). Biomarkers of myocardial injury, especially cTnT and IMA, might be used in HD patients, provided that an appropriate diagnostic interpretation is guarantee, according to individual baseine value, metabolism, and time of sampling. Moreover, IMA might be reliably applied to stratify the long-term risk of these patients, but not for diagnosing an ACS during or immediately post-HD.

Effect of Renal Failure on Peak Troponin Ic Level in Patients with Acute Myocardial Infarction

OBJECTIVES

Peak troponin Ic (cTnI) level could be influenced by renal function. We evaluated the effect of moderate to severe renal failure on peak cTnI level during acute myocardial infarction (AMI).

METHODS

One hundred and twenty-five consecutive patients admitted to the coronary care unit of a university hospital in France for primary angioplasty during AMI were retrospectively studied.

RESULTS

The correlations between peak cTnI level, peak creatine phosphokinase (CK) level, peak cTnI/peak CK ratio and creatinine clearance (CrCl) were assessed. The peak cTnI/peak CK ratio was considered in order to standardize the peak cTnI level with the extent of myocardial necrosis. There was no significant correlation between CrCl and peak CK (r = 0.01, p = 0.95), peak cTnI (r = -0.08, p = 0.38) or the peak cTnI/peak CK ratio (r = -0.14, p = 0.13). There was a trend towards higher peak cTnI in patients with moderate to severe renal failure. The peak cTnI/peak CK ratio did not significantly differ among patients according to CrCl stratification, whereas the ratio of log-transformed values was significantly higher in patients with moderate to severe renal failure.

CONCLUSION

In patients with AMI, the peak cTnI level seemed to be influenced by renal function.

Potential value for new diagnostic markers in the early recognition of acute coronary syndromes

The diagnostic approach to acute coronary syndromes (ACS) remains one of the most difficult and controversial challenges facing emergency physicians. In recent years, cardiac troponins have emerged as the biochemical "gold standard" for diagnosis of patients with acute chest pain, enhancing our ability to recognize ACS. Early diagnosis and treatment of myocardial ischemia improve patient outcomes, but conventional markers are often nondiagnostic at the time of arrival at the emergency department. Promising new biomarkers, which appear earlier after the onset of ischemia, are being studied and integrated into clinical practice. Some are markers of myocyte necrosis, but others, including ischemia-modified albumin and natriuretic peptides, detect myocardial ischemia and myocardial dysfunction. The aim of the present article is to review the diagnostic approach to ACS, focusing on recent literature describing novel biochemical markers. If ongoing and future studies confirm their role in probability-based models risk assessment, a new era in the diagnostic approach to ACS may be dawning.

The effect of magnesium sulfate treatment on serum cardiac troponin I levels in preeclamptic women

AIM

To investigate serum cardiac troponin I levels before and after magnesium sulfate treatment in preeclamptic pregnant women.

MATERIALS AND METHODS

Fifty-five pregnant women were included in the prospectively planned study. Study group patients (n = 25) were pregnant women hospitalized with a preeclampsia diagnosis while the control group (n = 30) were pregnant women with no medical or obstetric problem who had been attending the antenatal clinic. Serum cardiac troponin I levels were compared in the normal pregnant women and in preeclamptic pregnant women. These levels were also compared in the preeclamptic women before and after magnesium sulfate treatment. Mann-Whitney U-test was used for statistical analysis.

RESULTS

Groups were similar with respect to age, gravity, parity, and gestational age. The median serum cardiac troponin I levels in preeclamptic patients was 0.20 ng/ml (0.02-4.53) before treatment and 0.09 ng/ml (0.02-3.91) after treatment, while it was 0.02 ng/ml (0.0-0.05) in the control group. The serum cardiac troponin I level in the preeclamptic group was significantly high (P < 0.01), and pretreatment values in this group were significantly higher compared with post-treatment values (P < 0.01)

CONCLUSION

Cardiac troponin I is a sensitive parameter for indicating minor myocardial damage which may occur in preeclampsia and for evaluating the efficiency of magnesium sulfate treatment.

Cardiac troponin I and creatine kinase isoenzyme MB in patients with intradialytic hypotension

BACKGROUND

Intradialytic hypotension (IH) has been long recognized as a common complication during hemodialysis (HD) therapy, but few studies have discussed IH-related myocardial injuries and the long-term prognosis of patients prone to IH (HP).

METHODS

We conducted a prospective study on 70 chronic HD patients who had no recent occurrences of acute coronary artery syndrome. The patients were divided into two groups: HP (n = 29) and IH resistant (n = 41). While they underwent HD therapy, we monitored and evaluated their baseline data and their patterns of cardiac troponin I (cTnI), creatine kinase, and creatine kinase isoenzyme MB.

RESULTS

The HP and IH-resistant patients had similar baseline cardiac marker levels that did not seem to be influenced by uneventful HD therapy. However, if during HD therapy the patients experienced an episode of symptomatic IH, they were found to have significant increases in the creatine kinase MB activity at the end of HD therapy and in the cTnI levels 44 h following HD. After 12 months, the HP patients with baseline cTnI levels > or =0.20 ng/ml were more likely to experience cardiovascular events or death (adjusted odds ratio 15.0, p = 0.012).

CONCLUSIONS

Our study showed that, after symptomatic IH episodes, the HP patients were more likely to suffer occult myocardial injuries. HP patients who have high cTnI levels should be closely monitored for cardiovascular diseases.

The increasing impact of laboratory medicine on clinical cardiology

The practice of cardiology continues to evolve along with a better understanding of the pathophysiology of cardiovascular disease and the development of new therapeutic procedures. Consequently, new demands are being made on the in vitro diagnostics industry to improve the performance of existing cardiac markers and to develop novel markers for new cardiac disease indications. Indeed, in the last 20 years there has been a progressive increase in new laboratory tests for markers of cardiac diseases. Several highly sensitive and/or specific assays for the detection of myocardial ischemic damage as well as some immunoassays for cardiac natriuretic hormones, now considered a reliable marker of myocardial function, have become commercially available. In parallel, a growing number of some novel risk factors, which can be assessed and monitored by laboratory methods, have been added to the classical risk factors for cardiovascular disease. Finally, the recent explosion of genetic analysis may soon place at the clinical cardiologist's disposal many laboratory tests for defining the diagnosis at the molecular level, assessing new risk factors, and better targeting the pharmaceutical approaches in patients with cardiovascular disease. In the present article, after a brief description of the analytical tests included in these four groups, each group's impact on clinical cardiology is discussed in detail.

The diagnostic value of troponin T and myoglobin levels in acute myocardial infarction: a study in Turkish patients

This study compares the diagnostic value of troponin T (TnT) and myoglobin with creatinine kinase (CK) for myocardial infarction (MI) in a tertiary care centre in a developing nation. The study group comprised 33 acute myocardial infarction patients and 27 healthy controls. Receiver operating characteristic curves for TnT, myoglobin and CK were drawn and areas under the curve calculated. At admission, myoglobin levels had greater diagnostic sensitivity than TnT or CK levels. After 2 h, myoglobin and TnT had equal sensitivity and specificity, whereas CK still had lower sensitivity than myoglobin and TnT. After 4 h there was no difference between the tests. It was concluded that myoglobin levels on admission and TnT at 2 h had the greatest diagnostic rate, whereas all the tests were similar after 4 h for MI.

Myocardial ischemia and cytokine response are associated with subsequent onset of infections after noncardiac surgery

Postoperative myocardial ischemia (POMI) is prevalent among patients after major noncardiac surgery. Surgery, as well as POMI, may modulate the immune system, potentially worsening patient outcome. We sought to investigate the modulation of soluble interleukin (IL)-6 and IL-10 by POMI and its association with increased postoperative infection rates. Two-hundred-three patients undergoing elective major abdominal, vascular, and orthopedic surgery participated in this prospective observational study. Perioperative management was standardized. Hemodynamic variables were kept within 20% of baseline. POMI was assessed by Holter electrocardiography starting at least 8 h before the induction of anesthesia and continued until 96 h after surgery. Twelve-lead electrocardiograms, cardiac enzymes, and immune variables were obtained at the time of admission to the hospital, before surgery, before the induction of anesthesia, after surgery, at the time of admission to the intensive care unit, and 6, 12, 18, 24, 36, 48, 72, 96, 120, 144, and 168 h after surgery. Infections were diagnosed according to the Centers for Disease Control criteria. The incidence of POMI was 27%, and the majority of cases (76%) occurred within the first 24 h after surgery. IL-6 and IL-10 levels significantly increased during surgery but did not differ between the POMI and Non-POMI groups. However, in the subset of patients who developed severe infections or sepsis (n = 47) a median of 3 days (range, 1-8 days) after surgery, the intraoperative increases of IL-6 and IL-10 in the POMI group were, respectively, 3 and 10 times higher compared with the increase in the Non-POMI group. By using a multifactorial analysis in these patients with severe infections, the type of surgical trauma was associated with an increased IL-6 response, whereas the increase in IL-10 was attributed to POMI. These findings suggest that immediate cytokine responses due to POMI and type of surgery might be relevant for the later onset of severe infections and sepsis.

IMPLICATIONS

Postoperative myocardial ischemia (POMI) occurred in 27% of patients after major noncardiac surgery. This was associated with an immediate augmented cytokine response in the first 12 h after surgery in patients who developed severe infections or sepsis 3 days later. POMI was associated with an increased interleukin (IL)-10 response, whereas IL-6 was associated with the type of surgery.

Test strategies for the detection of myocardial damage

In the space of half a century, cardiac marker testing has advanced incrementally from enzymes present in nearly all tissues to proteins having remarkable specificity for myocardium. Markers with other desirable properties, such as earlier release, have also been introduced and others may be anticipated, although a single perfect marker is not on the horizon. Optimum application of these new markers still requires improved robustness and harmonization of commercial assays, and continuing insights in the pathophysiology of acute coronary syndromes. As these advances occur, future testing will likely focus more on therapeutic decisions than on arbitrary diagnostic classifications.

Serum cardiac troponin I after conventional and minimal invasive coronary artery bypass surgery

We evaluated myocardial release of cardiac troponin I (cTnI) in patients treated with conventional coronary artery bypass grafting (CABG), which employs extracorporeal circulation, and different kinds of minimal invasive coronary artery bypass grafting (MICABG), a surgical technique where the operation is performed without extra-corporeal circulation. Furthermore, we evaluated the usefulness of serum cTnI measurement to detect perioperative myocardial infarction (PMI) after coronary artery bypass surgery. Thirty-one patients were included: sixteen underwent CABG, fifteen underwent different MICABG and five patients had PMI. Blood specimens for cTnI measurements were collected up to 72 hours after opening the graft. Aortic cross-clamping time was a minor determinant of myocardial damage; on the other side, the trauma during surgery correlated with the number of involved arteries and with the manoeuvre employed to obtain heart dislocation, and appeared a more important determinant of myocardial damage. In patients with PMI, the cumulative release of cTnI was higher than in patients free from PMI; however, only after 24-72 hours we observed significant differences in serum cTnI values, because the increased perioperative values of cTnI complicated the interpretation of the myocardial status and a single cut-off could not be used to exclude PMI.