"Ultra-sensitive" cardiac troponins: Requirements for effective implementation in clinical practice

Comparison of ADVIA Centaur ultra-sensitive and high-sensitive assays for troponin I in serum

Cardiac troponin I (cTnI) is a standard biomarker for the diagnosis of acute myocardial infarction (AMI). While older, ultra-sensitive cTnI (us-cTnI) assays use the 99th percentile as the reference threshold, newer high-sensitive cTnI (hs-cTnI) assays use the limit of detection or functional sensitivity instead. However, little has been done to systematically compare these two methods. The present study also served as a validation of hs-cTnI in our laboratory. Here, we compared the results obtained from the blood serum obtained from 8810 patients using the us-cTnI and the hs-cTnI assays run in tandem on the ADVIA Centaur XP analyser. We found that in 2279 samples the concentration of cTnI measured with the ultra-sensitive method was below the detection limit, while with the high-sensitive method, only 540 were below the detection limit. We also compared results from these assays with the ultimate diagnosis of a subset of individuals. The analysis of the results below cut-off with the ultra-sensitive method showed that this method would not detect 96 cases related to heart disorder. Overall, the main finding of our research is that hs-cTnI is the preferable option and is able to be deployed effectively in the laboratory setting.

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Measuring levels of cTnI is an important method of identifying heart-related disorders in the hospital setting.

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In the present study, the ultra-sensitive method did not detect 96 cases related to heart disorder.

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The high-sensitive cTnI assay the preferable option and is able to be deployed effectively in the laboratory setting.

A study protocol for the cardiac effects of a single dose of either oxytocin 2.5 IU or carbetocin 100 µg after caesarean delivery: a prospective randomized controlled multi-centre trial in Norway

Background: Both oxytocin and carbetocin are used to prevent uterine atony and post-partum haemorrhage after caesarean delivery in many countries, including Norway. Oxytocin causes dose-dependent ST-depression, troponin release, prolongation of QT-time and arrythmia, but little is known about myocardial effects of carbetocin. We have previously demonstrated comparable vasodilatory effects of oxytocin and carbetocin and are now undertaking a Phase 4 trial to investigate whether carbetocin causes similar changes to myocardial markers compared with oxytocin.

Methods: Our randomized controlled trial will be conducted at three obstetrics units at Oslo University Hospital and Akershus University Hospital, Norway. Planned enrolment will be of 240 healthy, singleton pregnant women aged 18 to 50 years undergoing planned caesarean delivery. Based on pilot study data, each participant will receive a one-minute intravenous injection of either oxytocin 2.5 IU or carbetocin 100 µg during caesarean delivery. The prespecified primary outcome is the change from baseline in high-sensitive troponin I plasma concentrations at 6–10 hours after study drug administration. Secondary outcomes include uterine tone grade at 2.5 and five minutes after study drug administration, adverse events for up to 48 hours after study drug administration, estimated blood loss within eight hours of delivery, need for rescue treatment and direct/indirect costs. Enrolment and primary analysis are expected to be completed by the end of 2021.

Discussion: Women undergoing caesarean delivery should be assessed for cardiovascular risk particularly as women with an obstetric history of pregnancy induced hypertension, gestational diabetes mellitus, preterm birth, placental abruption, and stillbirth are at increased risk of future cardiovascular disease. Any additional ischaemic myocardial risk from uterotonic agents will need to be balanced with the benefit of reducing the risk of postpartum haemorrhage. Any potential cardiotoxicity difference between oxytocin and carbetocin will help inform treatment decisions for pregnant women.

Registration: Clinicaltrials.gov NCT03899961 (02/04/2019).

Ultra-high sensitivity cardiac troponin-I concentration and left ventricular structure and function in women with ischemia and no obstructive coronary artery disease

Aims

Women are disproportionally impacted by ischemia and no obstructive coronary artery disease (INOCA), and such women are at increased risk of developing heart failure with preserved ejection fraction (HFpEF), however the mechanisms linking these conditions remain poorly understood. The aim of this study was to determine whether ultra-high sensitivity cardiac troponin I (u-hscTnI), an indicator of cardiomyocyte injury, is associated with abnormalities in myocardial perfusion and left ventricular (LV) structure and function in women with INOCA.

Methods

327 women with INOCA enrolled in the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study underwent vasodilator stress cardiac magnetic resonance imaging (CMRI) and u-hscTnI measurements (Simoa HD-1 Analyzer, Quanterix Corporation). Multivariable linear regression was used to evaluate associations between u-hscTnI concentrations and myocardial perfusion (MPRI), LV mass index and feature-tracking derived strain measures of LV function.

Results

u-hscTnI concentrations were quantifiable in 100% of the cohort and ranged from 0.004 to 79.6 pg/mL. In adjusted models, u-hscTnI was associated with LV mass index (+2.03; 95% CI 1.17, 2.89; p < 0.01) and early diastolic radial strain rate (SR) (+0.13; 95% CI 0.01, 0.25; p = 0.03), early diastolic circumferential SR (-0.04; 95% CI -0.08, 0.002; p = 0.06) and early diastolic longitudinal SR (-0.03; 95% CI -0.07, 0.002; p = 0.06). u-hscTnI was not associated with MPRI (p = 0.39) in adjusted models.

Conclusion

Together, these findings support cardiomyocyte injury as a putative pathway towards adverse LV remodeling and dysfunction; however, further research is needed to define the specific mechanism(s) driving myocellular injury in INOCA.

A study protocol for the cardiac effects of a single dose of either oxytocin 2.5 IU or carbetocin 100 µg after caesarean delivery: a prospective randomized controlled multi-centre trial in Norway

Background: Both oxytocin and carbetocin are used to prevent uterine atony and post-partum haemorrhage after caesarean delivery in many countries, including Norway. Oxytocin causes dose-dependent ST-depression, troponin release, prolongation of QT-time and arrythmia, but little is known about myocardial effects of carbetocin. We have previously demonstrated comparable vasodilatory effects of oxytocin and carbetocin and are now undertaking a Phase 4 trial to investigate whether carbetocin causes similar changes to myocardial markers compared with oxytocin. Methods: Our randomized controlled trial will be conducted at three obstetrics units at Oslo University Hospital and Akershus University Hospital, Norway. Planned enrolment will be of 240 healthy, singleton pregnant women aged 18 to 50 years undergoing planned caesarean delivery. Based on pilot study data, each participant will receive a one-minute intravenous injection of either oxytocin 2.5 IU or carbetocin 100 µg during caesarean delivery. The prespecified primary outcome is the change from baseline in high-sensitive troponin I plasma concentrations at 6-10 hours after study drug administration. Secondary outcomes include uterine tone grade at 2.5 and five minutes after study drug administration, adverse events for up to 48 hours after study drug administration, estimated blood loss within eight hours of delivery, need for rescue treatment and direct/indirect costs. Enrolment and primary analysis are expected to be completed by the end of 2021. Discussion: Women undergoing caesarean delivery should be assessed for cardiovascular risk particularly as women with an obstetric history of pregnancy induced hypertension, gestational diabetes mellitus, preterm birth, placental abruption, and stillbirth are at increased risk of future cardiovascular disease. Any additional ischaemic myocardial risk from uterotonic agents will need to be balanced with the benefit of reducing the risk of postpartum haemorrhage. Any potential cardiotoxicity difference between oxytocin and carbetocin will help inform treatment decisions for pregnant women. Registration: Clinicaltrials.gov NCT03899961 (02/04/2019).

Cardiac troponin elevation in patients with influenza virus infections

The association between acute infections and cardiac injury, including myocarditis and acute myocardial infarction, is now well established. We have performed a systematic literature review for analyzing the results of epidemiological studies that measured cardiac troponins (cTn) in patients with Influenza virus infections. Overall, 14 articles were finally identified and analyzed. Taken together, the results of the scientific literature suggest that cTn elevation is a relatively rare phenomenon in patients with Influenza virus infection, with frequency generally comprised between 0 and 33%, more likely in elderly patients with significant comorbidities. In patients with modest cTn elevations, this phenomenon is apparently self-limited, transient and reversible, and especially involves patients with Influenza A (especially H1N1). In the minority of patients exhibiting an abrupt appearance of cardiovascular symptoms and concomitant elevation of cTn values, the relative increase of this biomarker reflects the presence of an underlying cardiac injury, that can be either myocarditis or an acute ischemic episode. Enhanced cTn values can also be more frequently observed in Influenza patients with complicated disease, in those developing acute respiratory distress syndrome and cardiac dysfunction, as well as in those at higher risk of death. cTn measurement shall be considered a valuable option in all patients developing acute cardiovascular symptoms during Influenza virus infections, as well as in those bearing cardiac or extra-cardiac comorbidities who bear a higher risk of complications.

Coronary Vascular Function and Cardiomyocyte Injury: A Report From the WISE-CVD

OBJECTIVE

Women with symptoms or signs of myocardial ischemia but no obstructive coronary artery disease (INOCA) often have coronary vascular dysfunction and elevated risk for adverse cardiovascular events. We hypothesized that u-hscTnI (ultra-high-sensitivity cardiac troponin I), a sensitive indicator of ischemic cardiomyocyte injury, is associated with coronary vascular dysfunction in women with INOCA. Approach and Results: Women (N=263) with INOCA enrolled in the WISE-CVD study (Women's Ischemic Syndrome Evaluation-Coronary Vascular Dysfunction) underwent invasive coronary vascular function testing and u-hscTnI measurements (Simoa HD-1 Analyzer; Quanterix Corporation, Lexington, MA). Logistic regression models, adjusted for traditional cardiovascular risk factors were used to evaluate associations between u-hscTnI and coronary vascular function. Women with coronary vascular dysfunction (microvascular constriction and limited coronary epicardial dilation) had higher plasma u-hscTnI levels (both P=0.001). u-hscTnI levels were associated with microvascular constriction (odds ratio, 1.38 per doubling of u-hscTnI [95% CI, 1.03-1.84]; P=0.033) and limited coronary epicardial dilation (odds ratio, 1.37 per doubling of u-hscTnI [95% CI, 1.04-1.81]; P=0.026). u-hscTnI levels were not associated with microvascular dilation or coronary epicardial constriction.

CONCLUSIONS

Our findings indicate that higher u-hscTnI is associated with coronary vascular dysfunction in women with INOCA. This suggests that ischemic cardiomyocyte injury in the setting of coronary vascular dysfunction has the potential to contribute to adverse cardiovascular outcomes observed in these women. Additional studies are needed to confirm and investigate mechanisms underlying these findings in INOCA. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00832702.

Evaluating the Diagnostic and Prognostic Value of Biomarkers for Heart Disease and Major Adverse Cardiac Events in Patients With Muscular Dystrophy

AIMS

Heart disease is recognized as the leading cause of morbidity and mortality in patients with muscular dystrophy (MD). Our study demonstrates the clinical utility of cardiac biomarkers to improve the diagnosis of cardiomyopathy and prognostication of major adverse cardiac events (MACE) in these vulnerable patients.

METHODS AND RESULTS

We prospectively followed 117 patients (median age, 42 (interquartile range [IQR], 26-50) years; 49 [41.9%] women) at the Neuromuscular Multidisciplinary clinic diagnosed with a dystrophinopathy, limb-girdle MD, type 1 myotonic dystrophy, or facioscapulohumeral MD. We determined that B-type natriuretic peptide (BNP) and high-sensitive troponin I (hsTnI) were effective diagnostic markers of cardiomyopathy (area under the curve [AUC], 0.64; P=0.017; and AUC, 0.69; P=0.001, respectively). Patient risk stratification for MACE was based on cutoff values of BNP and hsTnI defined a priori as 30.5000 pg/mL and 7.6050 ng/L, respectively. Over a median follow-up period of 2.09 (IQR, 1.17-2.81) years there were 36 confirmed MACE. Multivariate regression analyses showed that patients with BNP and hsTnI levels above the respective cutoff values had a 3.70-fold (P=0.001) and 3.24-fold (P=0.002) greater risk of MACE, respectively, compared to patients with biomarker levels below. Furthermore, patients with biomarker levels above both cutoff values had a 4.08-fold (P=0.001) greater risk of MACE. Inflammatory biomarkers did not show clinical utility for heart disease in these patients.

CONCLUSION

Our study demonstrates important diagnostic and prognostic value of BNP and hsTnI as part of a comprehensive cardiac assessment to augment the management and treatment of heart disease in patients with MD.

Exploring the association between extra-cardiac troponin elevations and risk of future mortality

Although the measurement of cardiac troponin I (cTnI) and T (cTnT) has now become the cornerstone for diagnosing cardiac injury, both ischemic and non-ischemic, recent evidence has become available that many patients display extra-cardiac causes of cTn elevations and carry a considerably enhanced risk of future mortality. The current literature data suggests that cTn elevations may be equally common in patients with cardiac and extra-cardiac diseases. Among the latter cohort of patients, the leading extra-cardiac diseases which may be responsible for either cTnI or cTnT elevations include infectious diseases/sepsis, pulmonary disorders, renal failure, malignancy, as well as gastrointestinal, neurological and musculoskeletal diseases. What also emerges rather clearly from the current literature data, is that the risk of dying for extra-cardiac diseases is higher (i.e., between two to three-fold) in patients with extra-cardiac cTn elevations than in those with cardiac pathologies, and that the most frequent cause of death would then be infections/sepsis, followed by malignancy, respiratory disorders, myocardial infarction, gastrointestinal and neurological diseases, heart failure, stroke, cardiac arrhythmias, renal failure, psychiatric, metabolic, urogenital and musculoskeletal disorders. These figures would lead to conclude that there is a considerable risk that the underlying pathology causing cardiac injury and cTn elevation would then become the cause of death in these patients. This important evidence shall lead the way to defining appropriate and effective strategies for managing patients with extra-cardiac cTn elevations, so that their risk of future death could be prevented or limited.

Integrated diagnostics: the future of laboratory medicine?

The current scenario of in vitro and in vivo diagnostics can be summarized using the “silo metaphor”, where laboratory medicine, pathology and radiology are three conceptually separated diagnostic disciplines, which will increasingly share many comparable features. The substantial progresses in our understanding of biochemical-biological interplays that characterize many human diseases, coupled with extraordinary technical advances, are now generating important multidisciplinary convergences, leading the way to a new frontier, called integrated diagnostics. This new discipline, which is currently defined as convergence of imaging, pathology and laboratory tests with advanced information technology, has an enormous potential for revolutionizing diagnosis and therapeutic management of human diseases, including those causing the largest number of worldwide deaths (i.e. cardiovascular disease, cancer and infectious diseases). However, some important drawbacks should be overcome, mostly represented by insufficient information technology infrastructures, costs and enormous volume of different information that will be integrated and delivered. To overcome these hurdles, some specific strategies should be defined and implemented, such as planning major integration of exiting information systems or developing innovative ones, combining bioinformatics and imaging informatics, using health technology assessment for assessing cost and benefits, providing interpretative comments in integrated reports, developing and using expert systems and neural networks, overcoming cultural and political boundaries for generating multidisciplinary teams and integrated diagnostic algorithms.

PREDICT: a checklist for preventing preanalytical diagnostic errors in clinical trials

Although the importance of guaranteeing a high level of preanalytical quality in routine diagnostic testing has already been largely acknowledged over the past decades, minor emphasis is currently being placed on the fact that accurate performance and standardization of many preanalytical activities are also necessary prerogatives of clinical trials. Reliable evidence exists that clear indications on how to manage the different preanalytical steps are currently lacking in many clinical trials protocols, nor have detailed authoritative documents been published or endorsed on this matter to the best of our knowledge. To fill this gap, the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for Preanalytical Phase (WG-PRE) will provide here a specific checklist for preventing preanalytical diagnostic errors in clinical trials (PREDICT), especially focused on covering the most important preanalytical aspects of blood sample management in clinical studies, and thus encompassing test selection, patient preparation, sample collection, management and storage, sample transportation, as well as specimen retrieval before testing. The WG-PRE members sincerely hope that these recommendations will provide a useful contribution for increasing the success rate in clinical trials.

Predicting mortality with cardiac troponins: recent insights from meta-analyses

The introduction of cardiac troponin (cTn) testing in clinical practice has been one of the most important breakthroughs that have occurred in the recent history of laboratory medicine. Although it is now uncontestable that cTn values are essential for diagnosing acute coronary syndrome (ACS), solid evidence is also emerging that assessment of either cardiac troponin I (cTnI) or T (cTnT) may provide valuable prognostic information in the general healthy population, as well as in patients with a vast array of cardiac and extra-cardiac diseases. We have hence performed a critical review of the scientific literature for identifying meta-analyses which have investigated the potential contribution of cTns in predicting the risk of death in health and disease. According to the articles identified with our research, we can conclude that increased cTn values may be considered independent risk factors for all-cause mortality in the general population, as well as in patients with ACS, in those undergoing revascularization procedures, or with stable coronary artery disease (CAD), heart failure (HF) and atrial fibrillation (AF). Measurement of cTn may then be helpful for stratifying the mortality risk in non-cardiac hospitalized patients, in those with critical illness or sepsis, syncope, stroke, acute aortic dissection, pulmonary diseases, brain injury, renal failure, vascular and non-cardiac surgery. Although this evidence has notable clinical implications, the cost-effectiveness of population screening with high-sensitivity (hs) cTn immunoassays has not been proven so far.