Evaluation of Changes in Cardiac Troponin I Levels After Direct Current Cardioversion in Patients With Atrial Fibrillation.

INTRODUCTION: Direct current cardioversion (DCCV) of atrial fibrillation (AF) is a procedure used to restore normal heart rhythm. Cardiac biomarkers, such as cardiac troponin I (cTnI), are elevated in situations where injury-myocardial cell necrosis is induced. AIM: The aim of the present study was to investigate the change in cTnI levels, i.e., whether a myocardial injury is present, in patients with AF whose elective treatment was synchronized DCCV via a biphasic defibrillator. METHODS: The study sample included 59 patients who underwent synchronized DCCV for AF reversion. Measurement of cTnI before and after DCCV (one, three, and six hours) was performed by blood sampling and subsequent assay. RESULTS: It was observed that the value of cTnI did not change (<0.1 ng/mL) after DCCV at the measurement time points (one, three, and six hours). In addition, the value of cTnI remained constant (<0.1 ng/mL) in relation to the energy delivered, before DCCV and after DCCV (one, three, and six hours). However, it was found that there was a correlation between the outcome (AF reversion or not) and the energy used (joules). CONCLUSIONS: Synchronized DCCV with a biphasic defibrillator did not cause myocardial injury in any of the patients, as there was no change in cTnI values before and after DCCV.

Chest Pain in Primary Care: A Systematic Review of Risk Stratification Tools to Rule Out Acute Coronary Syndrome.

PURPOSE: Chest pain frequently poses a diagnostic challenge for general practitioners (GPs). Utilizing risk stratification tools might help GPs to rule out acute coronary syndrome (ACS) and make appropriate referral decisions. We conducted a systematic review of studies evaluating risk stratification tools for chest pain in primary care settings, both with and without troponin assays. Our aims were to assess the performance of tools for ruling out ACS and to provide a comprehensive review of the current evidence. METHODS: We searched PubMed and Embase for articles up to October 9, 2023 concerning adult patients with acute chest pain in primary care settings, for whom risk stratification tools (clinical decision rules [CDRs] and/or single biomarker tests) were used. To identify eligible studies, a combination of active learning and backward snowballing was applied. Screening, data extraction, and quality assessment (following the Quality Assessment of Diagnostic Accuracy Studies-2 tool) were performed independently by 2 researchers. RESULTS: Of the 1,204 studies screened, 14 were included in the final review. Nine studies validated 7 different CDRs without troponin. Sensitivities ranged from 75.0% to 97.0%, and negative predictive values (NPV) ranged from 82.4% to 99.7%. None of the CDRs outperformed the unaided judgment of GP's. Five studies reported on strategies using troponin measurements. Studies using high-sensitivity troponin showed highest diagnostic accuracy with sensitivity 83.3% to 100% and NPV 98.8% to 100%. CONCLUSION: Clinical decision rules without troponin and the use of conventional troponin showed insufficient sensitivity to rule out ACS in primary care and are not recommended as standalone tools. High-sensitivity troponin strategies are promising, but studies are limited. Further prospective validation in primary care is needed before implementation.

The Role of Troponin Testing in Patients with Supraventricular Tachycardia, Systematic Review and Meta-Analysis.

BACKGROUND: Supraventricular tachycardia (SVT) is commonly evaluated in the emergency department (ED). While troponin has been shown to be elevated in SVT, its usefulness for predicting coronary artery disease and future adverse cardiovascular outcomes has not been shown. OBJECTIVES: We aimed to evaluate the prognostic utility of troponin measurement as part of SVT management in the ED. METHODS: We performed a literature search in the PubMed and Scopus databases from inception to August 30, 2023, including all studies reporting troponin measurements in adult patients (age > 18 years) presenting to the ED with supraventricular tachycardia. The primary outcome of interest for this study was the prevalence of elevated troponin in patients with SVT. Secondary outcomes included the prevalence of major adverse cardiac events (MACE) and additional cardiac testing with significant findings. RESULTS: We included 7 studies (500 patients) in our analysis. Six studies reported the number of patients with SVT and elevated troponin, with a pooled prevalence of 46% (95% CI 27-66%, I2 93%). The pooled prevalence of all MACE in our study was 6% (95% CI 1-25%), while the prevalence for MACE among patients with elevated serum troponin levels was 11% (95% CI 4-27%). CONCLUSIONS: Troponin levels are frequently ordered for ED patients with SVT and are often elevated. However, this review suggests that they have low prognostic value in predicting MACE.

Kidney function-specific cut-off values of high-sensitivity cardiac troponin T for the diagnosis of acute myocardial infarction.

Background: The diagnosis of acute myocardial infarction (AMI) using high-sensitivity cardiac troponin T (hs-cTnT) remains challenging in patients with kidney dysfunction. Methods: In this large, multicenter cohort study, a total of 20 912 adults who underwent coronary angiography were included. Kidney function-specific cut-off values of hs-cTnT were determined to improve the specificity without sacrificing sensitivity, as compared with that using traditional cut-off value (14 ng/L) in the normal kidney function group. The diagnostic accuracy of the novel cut-off values was validated in an independent validation cohort. Results: In the derivation cohort (n = 12 900), 3247 patients had an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. Even in the absence of AMI, 50.2% of participants with eGFR <60 mL/min/1.73 m2 had a hs-cTnT concentration ≥14 ng/L. Using 14 ng/L as the threshold of hs-cTnT for diagnosing AMI led to a significantly reduced specificity and positive predictive value in patients with kidney dysfunction, as compared with that in patients with normal kidney function. The kidney function-specific cut-off values were determined as 14, 18 and 48 ng/L for patients with eGFR >60, 60-30 and <30 mL/min/1.73 m2, respectively. Using the novel cut-off values, the specificities for diagnosing AMI in participants with different levels of kidney dysfunction were remarkably improved (from 9.1%-52.7% to 52.8-63.0%), without compromising sensitivity (96.6%-97.9%). Similar improvement of diagnostic accuracy was observed in the validation cohort (n = 8012). Conclusions: The kidney function-specific cut-off values of hs-cTnT may help clinicians to accurately diagnose AMI in patients with kidney dysfunction and avoid the potential overtreatment in practice.

Utility of rest magnetocardiography in patients presenting to the emergency department with chest pain: A case series on the CardioFlux MCG.

Background: Magnetocardiography (MCG) may provide a rapid diagnostic option for patients presenting with chest pain in the emergency department (ED). Case summaries: This case series presents two instances from a multicenter study, where MCG could have served as a rapid, non-invasive diagnostic tool for chest pain patients. In both cases, multiple high-sensitivity troponin (hsTn) tests yielded incorrect evidence of ischemia. In the first case, multiple positive hsTn tests led to the patient requiring 23 h of observation care, while MCG rapidly ruled out acute coronary syndrome (ACS). In the second case, MCG revealed findings indicative of cardiac ischemia where serial ECGs did not indicate ischemia and serial hsTns were normal. Subsequent cardiac catheterization confirmed 99 % stenosis in the patient's left main and left anterior descending arteries, necessitating coronary artery bypass grafting (CABG). Conclusion: MCG offers a rapid, painless, non-invasive, radiation free assessment for patients presenting with acute chest pain. Integrating MCG into ED workflows has the potential to improve throughput, reduce the need for subsequent patient observation or inpatient admission, and minimize or eliminate the need for other more expensive non-invasive cardiac testing. MCG avoids some of the problems associated with other methods for diagnosing ischemia. MCG does not involve radiation or the use of pharmacologic agents which have a risk for allergic reactions and anaphylaxis, or the need for an intravenous line. Stress tests are frequently contraindicated or unable to be performed in patients on various medications, may require patient cooperation and in the case of exercise stress tests, the patient's capability to exercise. MCG requires no special patient preparation.

Comparative Study of Laboratory Versus Bedside High-Sensitivity Troponin I in the Emergency Medicine Department of a Tertiary Care Hospital in India.

BACKGROUND:  Evaluating high-sensitivity troponin I levels in emergency medicine is critical for diagnosing acute myocardial infarction (AMI). This study aims to evaluate the central laboratory versus bedside troponin I test in the emergency department of a tertiary care center. MATERIAL AND METHODS:  This prospective observational study was conducted at Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pune, Maharashtra, India, from October to December 2023. Patient samples were analyzed in the central laboratory using the Dimension EXL 200 (Siemens® Healthcare Diagnostics Inc., Erlangen, Germany) as the gold standard test and through point-of-care testing using the TriageTrue® (Quidel Corporation, San Diego, CA) high-sensitivity troponin I kit, which was run on the Triage® MeterPro® device (Quidel Corporation, San Diego, CA). This device quantitatively determines troponin I in ethylenediaminetetraacetic acid-anticoagulated whole blood and plasma specimens. The results were compared. Statistical analysis was performed using SPSS version 18 (SPSS Inc., Chicago, IL). An unpaired t-test was performed to compare the difference in time taken using the two testing methods. RESULT:  The mean time for obtaining troponin I results was substantially shorter with bedside testing (14.91 minutes, standard deviation (SD) = 0.5) than with laboratory testing (119.1 minutes, SD = 5.03). Statistical analysis revealed a significant difference (t = -172.36, p < 0.001). A chi-square test was conducted to assess the disparity between the two testing methods, yielding a chi-square value of 32.64 and a p value of 0.00001, indicating a significant difference between bedside testing and laboratory testing. CONCLUSION: The bedside high-sensitivity troponin I test offers a considerable advantage over laboratory testing regarding turnaround time within the emergency medicine department in India. This rapid diagnostic capability is crucial for timely management, which is beneficial for patients inconclusive of acute coronary syndrome-like non-ST segment elevation myocardial infarction (NSTEMI). It is also cost-effective. It also reduces the emergency boarding time and may reduce the number of unnecessary admissions in healthcare facilities.

Half-Life and Clearance of Cardiac Troponin I and Troponin T in Humans.

BACKGROUND: Cardiac troponin (cTn) is key in diagnosing myocardial infarction (MI). After MI, the clinically observed half-life of cTn has been reported to be 7 to 20 hours, but this estimate reflects the combined elimination and simultaneous release of cTn from cardiomyocytes. More precise timing of myocardial injuries necessitates separation of these 2 components. We used a novel method for determination of isolated cTn elimination kinetics in humans. METHODS: Patients with MI were included within 24 hours after revascularization and underwent plasmapheresis to obtain plasma with a high cTn concentration. After at least 3 weeks, patients returned for an autologous plasma retransfusion followed by blood sampling for 8 hours. cTn was measured with 5 different high-sensitivity cTn assays. RESULTS: Of 25 included patients, 20 participants (mean age, 64.5 years; SD, 8.2 years; 4 women [20%]) received a retransfusion after a median of 5.8 weeks (interquartile range, 5.0-6.9 weeks) after MI. After retransfusion of a median of 620 mL (range, 180-679 mL) autologous plasma, the concentration of cTn in participants' blood increased 4 to 445 times above the upper reference level of the 5 high-sensitivity cTn assays. The median elimination half-life ranged from 134.1 minutes (95% CI, 117.8-168.0) for the Elecsys high-sensitivity cTnT assay to 239.7 minutes (95% CI, 153.7-295.1) for the Vitros high-sensitivity cTnI assay. The median clearance of cTnI ranged from 40.3 mL/min (95% CI, 32.0-44.9) to 52.7 mL/min (95% CI, 42.2-57.8). The clearance of cTnT was 77.0 mL/min (95% CI, 45.2-95.0). CONCLUSIONS: This novel method showed that the elimination half-life of cTnI and cTnT was 5 to 16 hours shorter than previously reported. This indicates a considerably longer duration of cardiomyocyte cTn release after MI than previously thought. Improved knowledge of timing of myocardial injury may call for changes in the management of MI and other disorders with myocardial injury.

Troponin Elevation in Asymptomatic Cancer Patients: Unveiling Connections and Clinical Implications.

PURPOSE OF THE REVIEW: Elevated troponin levels are well established e.g., for the diagnosis of suspected acute coronary syndrome in symptomatic patients. In contrast, troponin elevations in asymptomatic cancer patients emerge as a complex phenomenon, challenging traditional perceptions of its association solely with cardiac events. RECENT FINDINGS: Recent data support the predictive value of cardiac biomarker for all-cause mortality and cardiotoxicity in cancer patients. This review gives an overview about the current literature about cardiac troponins in prediction and identification of high-risk cancer patients. The overview is focusing on diagnostic challenges, biomarker significance, and gaps of knowledge. Latest publications highlight the relevance of cardiac troponin in risk analysis before cancer treatment as well as a potential diagnostic gatekeeper for further cardiological diagnostics and therapy.

Significance of detecting cardiac troponin I and creatine kinase MB in critically Ill children without primary cardiac illness.

Objective: To investigate the incidence of myocardial injury in children with critically ill children without primary cardiac disease and the association between elevated cardiac troponin I (cTnl) and creatine kinase MB (CK-MB) concentrations and disease progression and prognosis to guide early treatment. Methods: The serum cTnI and CK-MB concentrations of 292 children with critically ill children without primary cardiac disease in Yantai Yuhuangding Hospital between January 2021 and January 2024 were retrospectively analyzed within 24 h after entering the Pediatric Intensive Care Unit (PICU). The children were divided into normal and abnormal groups according to the myocardial marker results. The abnormal group was further divided into the cTnI-elevated, CK-MB-elevated, single-elevated (cTnI- or CK-MB-elevated) and double-elevated (cTnI- and CK-MB-elevated) groups. The differences in the clinical indicators and their relationships with prognosis for the groups were compared. Results: The incidence of myocardial injury among the critically ill children without primary cardiac disease was 55.1%. The incidence of myocardial injury in children with infectious diarrhea combined with moderate and severe dehydration reached 85.19%. The pediatric critical illness score; frequency of use of vasoactive drugs; hypotension, shock, heart failure, respiratory failure, and multiple organ dysfunction syndrome; and mortality indexes differed significantly for the normal and abnormal myocardial marker groups (P < 0.05). The single-elevated and normal groups only showed a difference in mortality (P < 0.017). The cTnI and CK-MB concentrations were negatively correlated with prognosis (P < 0.01). Conclusion: Myocardial injury, as evidenced by elevated cardiac biomarkers, is common in critically ill children without primary cardiac illness. cTnI and CK-MB are associated with outcomes. Shock, heart failure, and multiple organ dysfunction syndromes are independently associated with simultaneous elevations of CK-MB and cTnI concentrations. Further prospective studies are needed to elucidate the clinical utility of these biomarkers.

Association of Cardiac Troponin T With Coronary Atherosclerosis in Asymptomatic Primary Prevention People With HIV.

Background: Coronary plaque is common among people with HIV (PWH) with low-to-moderate traditional atherosclerotic cardiovascular disease (ASCVD) risk. Objectives: The purpose of this study was to determine the association of high-sensitivity cardiac troponin T (hs-cTnT) levels with coronary plaque characteristics and evaluate if hs-cTnT improves identification of these features beyond traditional ASCVD risk factors among PWH. Methods: Among PWH receiving stable antiretroviral therapy with low-to-moderate ASCVD risk and no known history of ASCVD, hs-cTnT levels and measures of plaque by coronary computed tomography angiography were assessed. Primary outcomes included the association of hs-cTnT level with the presence of any plaque, vulnerable plaque, coronary artery calcium (CAC) score, and Leaman score. Assessment of model discrimination of hs-cTnT for plaque characteristics was also performed. Results: The cohort included 708 U.S. participants with a mean age of 51 ± 6 years, 119 (17%) females, a median ASCVD risk score of 4.4% (Q1-Q3: 2.5%-6.6%), and a median hs-cTnT level of 6.7 ng/L (detectable level ≥6 ng/L in 61%). Any plaque was present in 341 (48%), vulnerable plaque in 155 (22%), CAC>100 in 68 (10%), and a Leaman score >5 in 105 (15%). After adjustment for ASCVD risk score, participants with hs-cTnT >9.6 ng/L (highest category) versus an undetectable level (<6 ng/L) had a greater relative risk for any plaque (1.37, 95% CI: 1.12-1.67), vulnerable plaque (1.47, 95% CI: 1.16-1.87), CAC>100 (2.58, 95% CI: 1.37-4.83), and Leaman score >5 (2.13, 95% CI: 1.32-3.46). The addition of hs-cTnT level modestly improved the discrimination of ASCVD risk score to identify critical plaque features. Conclusions: In PWH without known ASCVD, hs-cTnT levels were strongly associated with and improved prediction of subclinical coronary plaque. (Evaluating the Use of Pitavastatin to Reduce the Risk of Cardiovascular Disease in HIV-Infected Adults [REPRIEVE]; NCT02344290).

Case Report: Acute myocarditis in a patient with Duchenne muscular dystrophy.

Background: Cardiovascular complications are the leading cause of death among individuals with Duchenne muscular dystrophy (DMD). However, due to the difficulty in evaluating individuals with inactive DMD, acute myocardial injury may be overlooked. Case presentation: An 11-year-old boy with DMD presented to the emergency department with a 5-day history of persistent nasal congestion, runny nose, and cough. He was regularly taking prednisolone acetate, angiotensin-converting enzyme (ACE) inhibitors, and ß-blockers for suspected DMD-associated cardiomyopathy. Upon presentation, a substantially elevated cardiac troponin I (cTnI) level of 19.8 µg/L and abnormal electrocardiogram (ECG) results were detected. Further cardiac magnetic resonance imaging (CMR) showed myocardial inflammation with localized T2 hyperintensity from the basal to middle lateral and inferior walls, as well as late gadolinium enhancement (LGE) from the basal to apical inferior lateral walls, supporting a diagnosis of acute myocarditis. Subsequently, the patient showed clinical improvement in response to combination treatment with intravenous immunoglobulin, oral prednisolone acetate, potassium chloride sustained-release tablets, anti-heart failure medication, and broad-spectrum antibiotics. Conclusions: We report a rare case of acute myocarditis in a patient with DMD, potentially due to upper respiratory tract infection. This case highlights the importance of early myocarditis recognition and treatment in patients with DMD.

Significance of an Early Repeat Troponin Measurement Upon Presentation to the Hospital for Acute Heart Failure.

BACKGROUND: Higher cardiac troponin is associated with worse outcomes in patients with acute heart failure. The significance of repeat measurements over hours remains unclear. We assessed whether a repeat measurement and the Δ between measurements of high-sensitivity cardiac troponin I (hs-cTnI) were associated with outcomes in hypervolemic patients with acute heart failure without acute coronary syndrome. METHODS AND RESULTS: We analyzed 582 individuals from AKINESIS (Acute Kidney Injury Neutrophil Gelatinase-Associated Lipocalin Evaluation of Symptomatic Heart Failure Study) with hs-cTnI measured ≤12 hours from admission and repeated ≤6 hours thereafter. Associations between hs-cTnI levels and their Δ with short-term (death, intensive care unit admission, receipt of inotropes, or positive pressure ventilation during hospitalization) and long-term (death or heart failure readmission within 1 year) outcomes were assessed. The average age was 69±13 years, 62% were men, 65% were White, 46% had coronary artery disease, and 22% had chest pain. Median hs-cTnI levels were 27 (interquartile range [IQR], 13-62) ng/L initially and 28 (IQR, 14-68) ng/L subsequently, with a Δ of 0 [IQR, -2 to 4] ng/L over 3.4±1 hours. Only the second measurement was associated with short-term outcomes (odds ratio, 1.14 per 2-fold higher [95% CI, 1.02-1.28]). Both individual measurements and the Δ were associated with long-term outcomes (hazard ratios, 1.09, 1.12, and 1.16 for first, second, and Δ, respectively). Associated risk for the first and second measurements were not constant over the year but highest early after being measured and decreased over 1 year. CONCLUSIONS: Repeat measurements of hs-cTnI over hours can identify individuals with acute heart failure without acute coronary syndrome at risk for short- and long-term outcomes.

Cardiac biomarker concentrations in cats with elevated pancreatic lipase concentrations.

BACKGROUND: Cardiac biomarker concentrations are elevated in dogs with pancreatitis, but it is unknown if this is also the case for cats. METHODS: The serum feline pancreatic lipase immunoreactivity (fPLI) of serum samples from 60 cats was quantified using the Spec fPL assay. Serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin I (HST) concentrations were also measured using commercial assays. RESULTS: Five of 20 cats with fPLI concentrations of 8.8 mg/L or more had above reference interval NT-proBNP concentrations. Serum NT-proBNP concentrations were not correlated with fPLI concentrations (p = 0.31) and were not different in each diagnostic category for fPLI results (p = 0.24). Serum HST concentrations were positively correlated with fPLI concentrations (r = 0.278, 95% confidence interval: 0.02‒0.50, p = 0.03). However, they were not significantly different in each diagnostic category for fPLI results (p = 0.16). LIMITATIONS: Unidentified co-variates could contribute to the association between fPLI and cardiac biomarker concentrations. CONCLUSIONS: Cats with elevated fPLI concentrations may have elevated cardiac biomarker concentrations.

Association between peak troponin level and prognosis among patients admitted to intensive cardiovascular care unit.

INTRODUCTION: High-sensitivity cardiac troponin (hs-cTn) is a key biomarker for myocardial injury, yet its prognostic value in intensive cardiovascular care units (ICCU) remains poorly understood. We aimed to assess the association between peak hs-cTn levels and prognosis in ICCU patients. METHODS: All patients admitted to a tertiary care center ICCU between July 2019 - July 2023 were prospectively enrolled. Patients were divided into five groups according to their peak hs-cTnI levels: A) hs-cTnI <100 ng/L; B) hs-cTnI of 100-1000 ng/L; C) hs-cTnI of 1000-10,000 ng/L; D) hs-cTnI of 10,000-100,000 ng/L and E) hs-cTnI ≥100,000 ng/L. The primary outcome was all-cause mortality at one year. RESULTS: A total of 4149 patients (1273 females [30.7 %]) with a median age of 69 (IQR 58-79) were included. Group E was highly specific for myocardial infarction (97.4 %) and especially for ST segment elevation myocardial infarction (STEMI) (87.5 %). Patients in group E were 56 % more likely to die at 1-year in an adjusted Cox model (95 % CI 1.09-2.23, p = 0.014) as compared with group A. Subgroup analyses revealed that among STEMI patients, higher peak hs-cTnI levels were not associated with higher mortality rate (HR 1.04, 95 % CI 0.4-2.72, p = 0.9), in contrast to patients with NSTEMI (HR 7.62, 95 % CI 1.97-29.6, p = 0.003). CONCLUSIONS: Peak hs-cTnI levels ≥100,000 ng/L were linked to higher one-year mortality, largely indicative of large myocardial infarctions. Notably, the association between elevated hs-cTnI levels and mortality differed between STEMI and NSTEMI patients, warranting further investigation.

How to Approach Patients with Acute Chest Pain.

Acute coronary syndrome (ACS) is associated with high mortality rates. Although the goal was to achieve a missed diagnosis rate of < 1%, the actual data showed a rate of > 2%. Chest pain diagnosis has remained unchanged over the years and is based on medical interviews and electrocardiograms (ECG), with biomarkers playing complementary roles. We aimed to summarize the key points of medical interviews, ECG clinics, use of biomarkers, and clinical scores, identify problems, and provide directions for future research. Medical interviews should focus on the character and location of chest pain (is it accompanied by radiating pain?) and the duration, induction, and ameliorating factors. An ECG should be recorded within 10 minutes of the presentation. The serial performance of an ECG is recommended for emergency department (ED) evaluation of suspected ACS. Characteristic ECG traces, such as Wellens syndrome and De Winter T-waves, should be understood. Therefore, troponin levels in all patients with suspected ischemic heart disease should be examined using a highly sensitive assay system. Depending on the ED facility, the patient should be risk stratified by serial measurements of cardiac troponin levels (re-testing at one hour would be preferred) to determine the appropriate time to perform an invasive strategy for a definitive diagnosis. The diagnostics should be based on Bayes' theorem; however, care should be taken to avoid the influence of heuristic bias.

A rapid non-invasive wearable device for assessing cardiac troponin.

BACKGROUND: Chest pain, a common emergency department 35 (ED) presentation, requires rapid evaluation. Optical technology-based non-invasive wearable devices (Infrasensor, RCE, Carlsbad, CA) rapidly and transcutaneously assesses cardiac Troponin I (cTnI). OBJECTIVES: To perform a pilot study describing the performance of the Infrasensor in cTnI defined cohorts. METHODS: This was a 10-hospital prospective observational study in healthy US subjects with a normal cTnI, and in patients with an elevated local cTnI. Healthy subjects were without disease, defined by a negative questionnaire and bloodwork, had a 3-minute Infrasensor measurement and blood samples for high-sensitivity cardiac troponin I (hs-cTnI), n-terminal pro-B-type natriuretic peptide (NTproBNP), creatinine, and glycosylated hemoglobin (HbA1c). Elevated cTnI's patients had the same Infrasensor and blood sample measurements. Using a cross validation technique, a cTnI based binary classification model that did, and did not, include age was trained with 80%, and validated on 20% (n=168; elevated hs-cTnI equally distributed across 5 folds) of the overall cohort. RESULTS: Of 840 patients, 727 (87.5%) were non-elevated cTnI controls and the remainder, n=113, had elevated cTnI. Median (25th, 75th percentiles) age was 61 (52, 71) and 48 (32, 57) years for the elevated and healthy control cohorts, respectively. Overall, 50.5% were female, with 29.2% and 52.7% in the elevated and non-elevated troponin cohorts respectively. Overall, the sensitivity, specificity, negative and positive predictive values of the Infrasensor for identifying an elevated cTnI were 0.9, 0.7, 0.98 and 0.48 respectively, with a C-statistic of 0.90 (0.89-0.99). CONCLUSIONS: The Infrasensor identifies elevated cTnI within 3 minutes of application.

Sex-specific high-sensitivity troponin T cut-points have similar safety but lower efficacy than overall cut-points in a multisite U.S. cohort.

BACKGROUND: Data comparing the performance of sex-specific to overall (non-sex-specific) high-sensitivity cardiac troponin (hs-cTn) cut-points for diagnosing acute coronary syndrome (ACS) are limited. This study aims to compare the safety and efficacy of sex-specific versus overall 99th percentile high-sensitivity cardiac troponin T (hs-cTnT) cut-points. METHODS: We conducted a secondary analysis of the STOP-CP cohort, which prospectively enrolled emergency department patients ≥ 21 years old with symptoms suggestive of ACS without ST-elevation on initial electrocardiogram across eight U.S. sites (January 25, 2017-September 6, 2018). Participants with both 0- and 1-h hs-cTnT measures less than or equal to the 99th percentile (sex-specific 22 ng/L for males, 14 ng/L for females; overall 19 ng/L) were classified into the rule-out group. The safety outcome was adjudicated cardiac death or myocardial infarction (MI) at 30 days. Efficacy was defined as the proportion classified to the rule-out group. McNemar's test and a generalized score statistic were used to compare rule-out and 30-day cardiac death or MI rates between strategies. Net reclassification improvement (NRI) index was used to further compare performance. RESULTS: This analysis included 1430 patients, of whom 45.8% (655/1430) were female; the mean ± SD age was 57.6 ± 12.8 years. At 30 days, cardiac death or MI occurred in 12.8% (183/1430). The rule-out rate was lower using sex-specific versus overall cut-points (70.6% [1010/1430] vs. 72.5% [1037/1430]; p = 0.003). Among rule-out patients, the 30-day cardiac death or MI rates were similar for sex-specific (2.4% [24/1010]) vs. overall (2.3% [24/1037]) strategies (p = 0.79). Among patients with cardiac death or MI, sex-specific versus overall cut-points correctly reclassified three females and incorrectly reclassified three males. The sex-specific strategy resulted in a net of 27 patients being incorrectly reclassified into the rule-in group. This led to an NRI of -2.2% (95% CI -5.1% to 0.8%). CONCLUSIONS: Sex-specific hs-cTnT cut-points resulted in fewer patients being ruled out without an improvement in safety compared to the overall cut-point strategy.

NT-proBNP and Cardiac Troponin I, but Not Cardiac Troponin T, Are Associated With 7-Year Changes in Cardiac Structure and Function in Older Adults: The ARIC Study.

BACKGROUND: Higher circulating concentrations of NT-proBNP (N-terminal pro-B-type natriuretic peptide) and high-sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI) are associated with left ventricular remodeling and with incident heart failure. The associations of these cardiac biomarkers with changes in cardiac structure and function over time are uncharacterized. METHODS: Among 2006 participants in the ARIC prospective cohort study (Atherosclerosis Risk in Communities) who were free of overt cardiovascular disease and underwent echocardiography at study visits 5 (2011- 2013) and 7 (2018-2019), we assessed the associations of NT-proBNP, hs-cTnT, and hs-cTnI concentrations at visit 5 with changes in left ventricular structure and function between visits 5 and 7 (≈7-year change) using multivariable linear regression with the biomarkers modeled as restricted cubic splines. Models were adjusted for age, sex, race, body mass index, smoking, diabetes, hypertension, and renal function at visit 5; blood pressure and heart rate at both visits; and the baseline value of the echocardiographic parameter of interest. RESULTS: Mean±SD age was 74±4 years at visit 5; 61% were women; and 23% were Black adults. Median (25th-75th percentile) concentrations at visit 5 of NT-proBNP, hs-cTnT, and hs-cTnI were 87 ng/L (50-157 ng/L), 9 ng/L (6-12 ng/L), and 2.6 ng/L (1.9-3.9 ng/L). In adjusted models, elevated baseline concentrations of NT-proBNP and hs-cTnI were significantly associated with 7-year decline in left ventricular systolic function (ejection fraction, longitudinal and circumferential strain) and worsening diastolic indices. In contrast, elevated baseline concentrations of hs-cTnT were not significantly associated with 7-year changes in cardiac structure, systolic function, or diastolic function (all P>0.05). CONCLUSIONS: Higher concentrations of NT-proBNP and hs-cTnI, but not hs-cTnT, were associated with greater declines in left ventricular function over ≈7 years in late life independently of traditional cardiovascular risk factors.AQ.