Sandoval, Yader

Abstract Objectives Understanding whether the novel long-T ITC complex might assist in interpreting clinical prognostic utility compared to established cardiac biomarkers is needed. We determined long term major adverse cardiac events (MACE) and all-cause mortality (ACM) predicated on novel long-T ITC complex and high sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) assays in the emergency department (ED). Methods cTn assays were measured on the Mindray CL-1200i platform at presentation in consecutive patients enrolled in ‘Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon’ (MERITnI) (NCT05853042) trial with suspected ischemia. Sex specific 99th percentiles upper reference limits (URLs) were: hs-cTnI female 14 ng/L, male 15 ng/L; hs-cTnT female 10 ng/L, male 19 ng/L; long-T ITC complex 0.9 ng/L, same for female and male. Results Of 1,070 patients, 59.4 % were male, 43.4 % White, 45.5 % Black, and 39.5 % ≥65 years. Independent of biomarkers, a continuum of risk over 1 year showed MACE increased to 16.1 % and ACM to 16.5 %. Long-T ITC complex did not show a continuum change, increasing only 0.1 % (HR: 1.001 (1.0–1.001) per ng/L. However, hs-cTnI increased 1.8 % (HR: 1.018 [1.009–1.027] for each ng/L (p<0.0001) and hs-cTnT increased 0.3 % per ng/L (HR: 1.003 [1.001–1.006]) (p=0.0028). Between subjects ≤URLs and >URLs, MACE and ACM all biomarkers showed significant (p<0.0001) differences over 1 year. For MACE in those >URL long-T ITC complex increased 11.2–25.2 %, hs-cTnI 18.0–35.0 % and hs-cTnT 8.9–24.2 %. For ACM in those >URL long-T ITC complex increased 4.5–23.3 %, hs-cTnI 5.0–26.2 %, and hs-cTnT 3.6–24.1 %. Conclusions Novel long-T ITC complex did not provide new prognostic value to either hs-cTnI or hs-cTnT. Patients with increased hs-cTnI and hs-cTnT concentrations had marked increases in MACE and ACM risk at 1-year.

Abstract Background We determined whether circulating cardiac troponin I–cardiac troponin T–troponin C (ITC) complex containing long-form cardiac troponin T (long-T ITC) complex and ratios of high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) could differentiate myocardial infarction (MI) from chronic and acute non-MI myocardial injuries in patients with suspected acute coronary syndrome. Methods We measured long-T ITC complex, hs-cTnI, and hs-cTnT (Mindray) at 0- and 2-h in consecutive patients enrolled in the Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon (MERITnI) trial. Results Among the 882 subjects studied (median 3.0 h presentation), 47 had acute MI (5.3%), 116 had acute non-MI myocardial injury, and 90 had chronic myocardial injury. At 0 and 2 h, areas under the curve (AUC) significantly differentiated acute MI from chronic myocardial injury for long-T ITC complex (0.72 and 0.81, respectively; P = 0.0082) but not acute non-MI myocardial injury (AUC, 0.65 and 0.69, respectively; P = 0.23). 0 and 2 h AUCs for long-T ITC complex/hs-cTnT and hs-cTnI/hs-cTnT ratios also significantly differentiated acute MI from chronic myocardial injury (AUC, 0.79 and 0.86, respectively) and acute non-MI myocardial injury (AUC, 0.68 and 0.71, respectively). There was no biomarker concentration or ratio value discrimination between type 1 and type 2 MIs. Conclusions Long-T ITC concentrations and long-T ITC complex/hs-cTnT and hs-cTnI/hs-cTnT ratios may clinically assist in differentiating acute MI from non-MI myocardial injuries when evaluating patients with suspected acute coronary syndrome. ClinicalTrials.gov Registration Number: NCT05853042.

Abstract Background The clinical use and interpretation of cardiac troponins (cTn) in pediatric patients is heterogeneous. Content This review is based on an appraisal and synthesis of the available literature and discussions between International Federation of Clinical Chemistry and Laboratory Medicine Committee on Clinical Application of Cardiac Biomarkers members and pediatricians, cardiologists, emergency department physicians, and laboratorians. It aims to summarize current knowledge and best practices related to cTn measurements in pediatric patients, including which percentile should be applicable as the upper reference limit, and the influence of age, sex, and physiology on circulating concentrations. Preanalytical and analytical precautions, and a consensus on optimal interpretation of the reported results are discussed. Summary Current studies report high cTn concentrations in healthy infants and newborns. The nadir is reached at 1–3 years at which time concentrations gradually increase, reaching adult levels through puberty. The incidence of myocardial injury is reported to be low and dependent on whether the 97.5th or 99th percentile is chosen as the upper reference limit. The main clinical indication for testing appears to be suspicion of myo/pericarditis or traumatic chest injury. On occasion, cTn is measured in cases of possible heart failure and/or myocardial ischemia. There is heterogeneity among the limited clinical studies published. Most of the data are retrospective, and the current suggestions for clinical practice are thus largely based on expert opinion. More research is needed regarding all aspects of cTn testing in children, and suggestions for future research are included at the end of this review.

Abstract Background High-sensitivity cardiac troponin (hs-cTn) assays are recommended for the diagnosis of acute myocardial infarction. Here, we characterize the analytical performance of a next-generation hs-cTn assay, Elecsys® Troponin T hs Gen 6 (Roche Diagnostics International). Methods Surplus lithium-heparin plasma or serum samples from patients or healthy volunteers were run on Cobas® e 801, e 402, and Pro analyzers. Limits of blank (LoB), limits of detection (LoD), and limits of quantitation (LoQ) were determined according to CLSI EP17-A2, with target values of 1.0 and 1.5 ng/L for LoB/LoD and 3.0 ng/L (10% CV) and 1.5 ng/L (20% CV) for LoQ, respectively. Precision was measured, per CLSI EP17-A2, using 3 QC samples (approximately 4, 30, and 220 ng/L), 12 native samples, and 3 reagent lots. Linearity, per CLSI EP06-Ed2, was determined by diluting samples with cardiac troponin T (cTnT) concentration above the measuring range with a low/blank sample. Interference (per Glick) with endogenous and assay components at 5 cTnT concentrations was assessed. Results Measured values for LoB, LoD, and LoQ at 10% and 20% CV were 0.1 to 0.7 ng/L, 0.3 to 1.4 ng/L, 1.0 to 2.9 ng/L, and 0.4 to 1.2 ng/L, respectively. Repeatability CVs were 1.0 to 5.8% for mean cTnT concentrations of 2.6 to 9230 ng/L in lithium-heparin plasma. High precision was shown across lots, and linearity was observed across the measuring range (1.5 to 9500 ng/L, all Pearson's r = 1.00). No interferences were observed, specified up to ≤1000 mg/dL hemoglobin, ≤50 mg/dL [≤855 µmol/L] icterus/bilirubin, and ≤1200 ng/mL biotin. Conclusions The analytical performance characterization of the assay demonstrated high sensitivity, high precision at the low end and across the measuring range, and resistance to interference.

Abstract A challenge in the implementation of rapid risk-stratification algorithms for patients with suspected acute coronary syndrome is the turnaround time for cardiac troponin (cTn) from blood sampling to reporting of results. Measurement of cTn in whole blood using point of care (POC) offers a solution. There is lack of consensus on how these instruments should be assessed and deployed when implemented into routine practice. A pragmatic strategy is needed to balance the requirement for appropriate evaluation, validation and local verification of POC high sensitivity (hs) cTn assays whilst avoiding unnecessary duplication of previously conducted work using central laboratory assays. The International Federation of Clinical Chemistry and Laboratory Medicine Committee on Clinical Application of Cardiac Bio-Markers (IFCC C-CB) has developed an educational document to provide practical suggestions as to how hs-cTn POC assays may be implemented in acute health care settings and networks. The objective of this document is to provide a pragmatic framework for implementation of such systems. The article describes the validation and verification procedures and outlines what should be the responsibility of the manufacturers and provides recommendations on how a local verification may be undertaken before instruments are implemented into routine clinical practice.

Abstract Background Measurement of cardiac troponin (cTn) using high-sensitivity assays is recommended for the diagnosis of myocardial infarction. We determined sex-specific and uniform 99th percentile upper reference limits (URLs) using the new Elecsys® Troponin T high-sensitivity Gen 6 assay in a global, healthy reference range cohort. Methods Lithium-heparin plasma and serum samples were prospectively collected from apparently healthy individuals aged ≥20 years across 34 global sites in the United States, Europe, China, and Japan. cTnT was measured using the Troponin T high-sensitivity Gen 6 assay on the Cobas® e 801 analyzer. Exclusion criteria were defined according to the 2022 IFCC guidance. Uniform and sex-specific 99th percentile URLs and nonparametric 95% CIs were determined in plasma and serum separately and combined. Results The final study population comprised 4147 participants (52.5% female) with a median (25th–75th percentiles) age of 48.0 (33.0–59.0) years; 45.8%, 47.9%, 5.2%, and 1.1% were White, Asian, Black, and other/unknown, respectively. For sample matrices combined (n = 8294), 81.0% and 99.2% of cTnT values were above the limit of detection in females and males, respectively. Sex-specific 99th percentile URLs (95% CI) were 18 (16–23) ng/L for females and 32 (28–35) ng/L for males; the uniform 99th percentile URL was 27 (24–31) ng/L. URLs were comparable in plasma and serum samples. Conclusions This study determined sex-specific and uniform 99th percentile URLs for the Troponin T high-sensitivity Gen 6 assay that were comparable irrespective of the matrix used in a large, global, healthy reference population.

Abstract Aims Type 2 myocardial infarction due to myocardial oxygen supply–demand imbalance is associated with poor outcomes. There are no guidelines to inform care for these patients. The consensus on the assessment and management of type 2 myocardial infarction is gained. Methods and results An international e-Delphi study including experts in type 2 myocardial infarction identified through systematic review was conducted. Participants were asked to describe their approach to (i) definition and diagnosis, (ii) risk stratification, (iii) assessment of coronary artery disease and cardiac function, (iv) specialty management, (v) treatment and secondary prevention, and (vi) communication and rehabilitation. Statements generated in round one were circulated, with consensus defined a priori as ≥70% agreement on a 5-point Likert scale. Where no consensus was reached, statements were amended and recirculated for a final round. The response rate was 56% (38/68), 54% (37/68), and 72% (49/68) in the first, second, and third rounds, respectively. Following the first round, 67 unique statements were generated across six domains. Overall, consensus was achieved on 64% (43/67) of statements. Consensus was achieved for 42% (5/12) of statements on the diagnosis of type 2 myocardial infarction, 75% (3/4) on risk stratification, 50% (9/18) on the assessment of coronary artery disease and cardiac function, 60% (6/10), on specialty management, 100% (9/9) on treatment and secondary prevention, and 79% (11/15) on communication and rehabilitation. Conclusion Consensus was obtained across a number of domains for the assessment and management of patients with type 2 myocardial infarction. However, there was limited agreement amongst experts on the diagnostic criteria, which may benefit from refinement.

Abstract Background Several guidelines groups have made recommendations about how to use natriuretic peptides (NPs) to screen patients with diabetes for incipient heart failure. This group is at risk for undetected and stage B heart failure, where structural heart disease is present despite the absence of clinical signs and symptoms. These recommendations are based on trial data that suggest there are therapeutic options to benefit these patients. Content These guidelines do not adequately account for the marked analytic differences between NP assays nor their high degree of biological and analytical variability. Thus, without additional data and guidance, these recommendations could lead to excessive testing for some groups but might disadvantage others. In addition, these issues could lead to difficulties in the interpretation of values. Accordingly, the Committee on Clinical Applications of Cardiac Bio Markers of the International Federation of Clinical Chemistry has developed a consensus educational document to describe these difficulties and define areas where additional data are needed. Clinicians should be cognizant of differences in the assays for NPs, the high degree of variability of values, differences in sex and ethnicity and the need to factor in a variety of clinical and treatment variables in interpreting NP values. Summary These suggestions for diabetes eventually will include others at high risk. They will require close attention to the issues involved in measuring and interpreting NP values.

Abstract Background Cardiac troponin is the gold-standard biomarker for the evaluation of patients with suspected acute myocardial infarction (MI). Improvements in assay technology have led to high-sensitivity cardiac troponin assays that, when incorporated into accelerated diagnostic pathways, may rapidly diagnose or exclude acute MI more efficiently than conventional troponin assays. Content In this narrative review, we provide practical suggestions for implementing high-sensitivity cardiac troponin assays, review accelerated diagnostic pathways incorporating these assays, and review the impact of these assays on resource utilization and cost-effectiveness in relation to the evaluation of individuals with possible acute MI. Summary An increasing number of hospitals are transitioning to high-sensitivity cardiac troponin assays. This narrative review provides an overview of the potential benefits of this transition.