Association of cardiac biomarkers with long-term cardiovascular events in a community cohort.

MATERIALS AND METHODS: The study assessed major adverse cardiac events (MACE) (myocardial infarction, coronary artery bypass graft, percutaneous intervention, stroke, and death. Cox proportional hazards models assessed apolipoprotein AI (ApoA1), apolipoprotein B (ApoB), ceramide score, cystatin C, galectin-3 (Gal3), LDL-C, Non-HDL-C, total cholesterol (TC), N-terminal B-type natriuretic peptide (NT proBNP), high-sensitivity cardiac troponin (HscTnI) and soluble interleukin 1 receptor-like 1. In adjusted models, Ceramide score was defined by from N-palmitoyl-sphingosine [Cer(16:0)], N-stearoyl-sphingosine [Cer(18:0)], N-nervonoyl-sphingosine [Cer(24:1)] and N-lignoceroyl-sphingosine [Cer(24:0)]. Multi-biomarker models were compared with C-statistics and Integrated Discrimination Index (IDI). RESULTS: A total of 1131 patients were included. Adjusted NT proBNP per 1 SD resulted in a 31% increased risk of MACE/death (HR = 1.31) and a 31% increased risk for stroke/MI (HR = 1.31). Adjusted Ceramide per 1 SD showed a 13% increased risk of MACE/death (HR = 1.13) and a 29% increased risk for stroke/MI (HR = 1.29). These markers added to clinical factors for both MACE/death (p = 0.003) and stroke/MI (p = 0.034). HscTnI was not a predictor of outcomes when added to the models. DISCUSSION: Ceramide score and NT proBNP improve the prediction of MACE and stroke/MI in a community primary prevention cohort.

In a community cohort, where a wide range of biomarkers were evaluated, Ceramide score provided additive value over traditional cardiac risk factors alone for predicting stroke/MI. NT ProBNP provided additive value in prediction of MACE/death. Other biomarkers failed to improve the discrimination of these models.

High Baseline High-Sensitivity Cardiac Troponin T Concentrations and Risk of Index Acute Myocardial Infarction.

OBJECTIVE: To evaluate the diagnostic performance of the previously recommended baseline high-sensitivity cardiac troponin T (hs-cTnT) thresholds of 52 and 100 ng/L in identifying patients at high risk of acute myocardial infarction (AMI). PATIENTS AND METHODS: This study compared the positive predictive value (PPV) for index AMI of these high-risk hs-cTnT thresholds in adult patients in the emergency department undergoing hs-cTnT measurement. RESULTS: The adjudicated MAyo Southwest Wisconsin 5th Gen Troponin T ImplementatiON cohort included 2053 patients, with 157 (7.6%) who received a diagnosis of AMI. The hs-cTnT concentrations of greater than 52 and greater than 100 ng/L resulted in PPVs of 41% (95% CI, 35%-48%) and 57% (95% CI, 48%-66%). In patients with chest discomfort, hs-cTnT concentrations greater than 52 ng/L resulted in a PPV of 66% (95% CI, 56%-76%) and hs-cTnT concentrations greater than 100 ng/L resulted in a PPV of 77% (95% CI, 65%-87%). The CV Data Mart Biomarker cohort included 143,709 patients, and 3003 (2.1%) received a diagnosis of AMI. Baseline hs-cTnT concentrations greater than 52 and greater than 100 ng/L resulted in PPVs of 12% (95% CI, 11%-12%) and 17% (95% CI, 17%-19%), respectively. In patients with chest pain and hs-cTnT concentrations greater than 52 ng/L, the PPV for MI was 17% (95% CI, 15%-18%) and in those with concentrations greater than 100 ng/L, only 22% (95% CI, 19%-25%). CONCLUSION: In unselected patients undergoing hs-cTnT measurement, the hs-cTnT thresholds of greater than 52 and greater than 100 ng/L provide suboptimal performance for identifying high-risk patients. In patients with chest discomfort, an hs-cTnT concentration of greater than 100 ng/L, but not the European Society of Cardiology-recommended threshold of greater than 52 ng/L, provides an acceptable performance but should be used only with other clinical features.

Cardiac Troponin in Patients With Light Chain and Transthyretin Cardiac Amyloidosis: JACC: CardioOncology State-of-the-Art Review.

Cardiac amyloidosis (CA) is an infiltrative disease caused by amyloid fibril deposition in the myocardium; the 2 forms that most frequently involve the heart are amyloid light chain (AL) and amyloid transthyretin (ATTR) amyloidosis. Cardiac troponin (cTn) is the biomarker of choice for the detection of myocardial injury and is frequently found to be elevated in patients with CA, particularly with high-sensitivity assays. Multiple mechanisms of myocardial injury in CA have been proposed, including cytotoxic effect of amyloid precursors, interstitial amyloid fibril infiltration, coronary microvascular dysfunction, amyloid- and non-amyloid-related coronary artery disease, diastolic dysfunction, and heart failure. Regardless of the mechanisms, cTn values have relevant prognostic (and potentially diagnostic) implications in both AL and ATTR amyloidosis. In this review, the authors discuss the significant aspects of cTn biology and measurement methods, potential mechanisms of myocardial injury in CA, and the clinical application of cTn in the management of both AL and ATTR amyloidosis.

Imprecision of high-sensitivity cardiac troponin assays at the female 99th-percentile.

BACKGROUND: An analytical benchmark for high-sensitivity cardiac troponin (hs-cTn) assays is to achieve a coefficient of variation (CV) of ≤ 10.0 % at the 99th percentile upper reference limit (URL) used for the diagnosis of myocardial infarction. Few prospective multicenter studies have evaluated assay imprecision and none have determined precision at the female URL which is lower than the male URL for all cardiac troponin assays. METHODS: Human serum and plasma matrix samples were constructed to yield hs-cTn concentrations near the female URLs for the Abbott, Beckman, Roche, and Siemens hs-cTn assays. These materials were sent (on dry ice) to 35 Canadian hospital laboratories (n = 64 instruments evaluated) participating in a larger clinical trial, with instructions for storage, handling, and monthly testing over one year. The mean concentration, standard deviation, and CV for each instrument type and an overall pooled CV for each manufacturer were calculated. RESULTS: The CVs for all individual instruments and overall were ≤ 10.0 % for two manufacturers (Abbott CVpooled = 6.3 % and Beckman CVpooled = 7.0 %). One of four Siemens Atellica instruments yielded a CV > 10.0 % (CVpooled = 7.7 %), whereas 15 of 41 Roche instruments yielded CVs > 10.0 % at the female URL of 9 ng/L used worldwide (6 cobas e411, 1 cobas e601, 4 cobas e602, and 4 cobas e801) (CVpooled = 11.7 %). Four Roche instruments also yielded CVs > 10.0 % near the female URL of 14 ng/L used in the United States (CVpooled = 8.5 %). CONCLUSIONS: The number of instruments achieving a CV ≤ 10.0 % at the female 99th-percentile URL varies by manufacturer and by instrument. Monitoring assay precision at the female URL is necessary for some assays to ensure optimal use of this threshold in clinical practice.

Serial high sensitivity troponin sampling in patients with SARS-CoV-2 infection.

INTRODUCTION: Multiple studies have investigated the role of cardiac troponin (cTn) in the risk stratification of patients with COVID-19. Most of these investigations are based on cTn values at presentation and do not consider the prognostic significance of cTn changes over time. This study aimed to investigate the prognostic role of serial cTn measurements in patients hospitalized with COVID-19 with samples that were not obtained for clinical indications. METHODS: Patients hospitalized between April 2020 and March 2021 with PCR-confirmed SARS-CoV-2 infection were evaluated. Blood samples collected for any reason were stored for subsequent analysis. If clinical high sensitivity hs-cTnT (Roche) was not measured, samples were tested separately in batches. Hs-cTnI (Abbott) was also evaluated. RESULTS: There were 228 unique patients. There were 21 (9.2 %) deaths. No patient with a low hs-cTnT (<6 ng/L) died and 1 patient with low hs-cTnI (<5 ng/L) died. Myocardial injury was associated with higher odds of death, when defined by hs-cTnT (OR: 7.88, 95 % CI: 2.04-30.40, p = 0.003) or hs-cTnI (OR: 7.46, 95 % CI: 2.68-20.77, p < 0.001). This association remained after propensity weighting. An increasing pattern was associated with higher odds of death compared to a stable pattern for hs-cTnT (OR: 5.45, 95 % CI: 1.81-16.40, p = 0.003) and hs-cTnI (OR: 4.49, 95 % CI: 1.02-19.81, p = 0.048). Among patients with myocardial injury defined by hs-cTnT, an increasing pattern was associated with higher odds of death compared to a decreasing pattern (OR: 4.80, 95 % CI: 1.16-19.97, p = 0.031). CONCLUSIONS: Patients hospitalized with COVID-19 with myocardial injury have higher odds of death. Serial hs-cTn testing provides additional risk stratification in these patients.

An improved method for estimating low LDL-C based on the enhanced Sampson-NIH equation.

BACKGROUND: The accurate measurement of Low-density lipoprotein cholesterol (LDL-C) is critical in the decision to utilize the new lipid-lowering therapies like PCSK9-inhibitors (PCSK9i) for high-risk cardiovascular disease patients that do not achieve sufficiently low LDL-C on statin therapy. OBJECTIVE: To improve the estimation of low LDL-C by developing a new equation that includes apolipoprotein B (apoB) as an independent variable, along with the standard lipid panel test results. METHODS: Using ß-quantification (BQ) as the reference method, which was performed on a large dyslipidemic population (N = 24,406), the following enhanced Sampson-NIH equation (eS LDL-C) was developed by least-square regression analysis: [Formula: see text] RESULTS: The eS LDL-C equation was the most accurate equation for a broad range of LDL-C values based on regression related parameters and the mean absolute difference (mg/dL) from the BQ reference method (eS LDL-C: 4.51, Sampson-NIH equation [S LDL-C]: 6.07; extended Martin equation [eM LDL-C]: 6.64; Friedewald equation [F LDL-C]: 8.3). It also had the best area-under-the-curve accuracy score by Regression Error Characteristic plots for LDL-C < 100 mg/dL (eS LDL-C: 0.953; S LDL-C: 0.920; eM LDL-C: 0.915; F LDL-C: 0.874) and was the best equation for categorizing patients as being below or above the 70 mg/dL LDL-C treatment threshold for adding new lipid-lowering drugs by kappa score analysis when compared to BQ LDL-C for TG < 800 mg/dL (eS LDL-C: 0.870 (0.853-0.887); S LDL-C:0.763 (0.749-0.776); eM LDL-C:0.706 (0.690-0.722); F LDL-C:0.687 (0.672-0.701). Approximately a third of patients with an F LDL-C < 70 mg/dL had falsely low test results, but about 80% were correctly reclassified as higher (≥ 70 mg/dL) by the eS LDL-C equation, making them potentially eligible for PCSK9i treatment. The M LDL-C and S LDL-C equations had less false low results below 70 mg/dL than the F LDL-C equation but reclassification by the eS LDL-C equation still also increased the net number of patients correctly classified. CONCLUSIONS: The use of the eS LDL-C equation as a confirmatory test improves the identification of high-risk cardiovascular disease patients, who could benefit from new lipid-lowering therapies but have falsely low LDL-C, as determined by the standard LDL-C equations used in current practice.

The Role of Artificial Intelligence for Providing Scientific Content for Laboratory Medicine.

BACKGROUND: Artificial intelligence (AI) promises to become an important tool in the practice of laboratory medicine. AI programs are available online that can provide concise medical and laboratory information within seconds after a question is submitted. METHODS: We posed the following contemporary and relevant question for clinical chemists using an AI program: "Should labs eliminate CK-MB testing?" The results of this inquiry were critically reviewed by a cardiologist, emergency department physician, and clinical laboratorians for accuracy and appropriateness. RESULTS: An AI report answering this question was generated within 15 s. The experts felt that the information was inaccurate with the statements that CK-MB results are released earlier than cardiac troponin (cTn), and are more useful for detection of myocardial injury in patients with renal insufficiencies. The summary omitted discussion on the ongoing debate for periprocedural detection of acute myocardial infarction (MI), the perceived value for detection of reinfarction, the value in risk stratification compared to cTn, the economic justification for testing both CK-MB and cTn, and medicolegal aspects of testing when results are discordant. CONCLUSIONS: At this time, AI does not appear to be ready to be used by clinical laboratories for answering important practice questions.

Assessing GFR With Proenkephalin.

Introduction: In clinical practice, kidney (dys)function is monitored through creatinine-based estimations of glomerular filtration rate (eGFR: Modification of Diet in Renal Disease [MDRD], Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]). Creatinine is recognized as a late and insensitive biomarker of glomerular filtration rate (GFR). The novel biomarker proenkephalin (PENK) may overcome these limitations, but no PENK-based equation for eGFR is currently available. Therefore, we developed and validated a PENK-based equation to assess GFR. Methods: In this international multicenter study in 1354 stable and critically ill patients, GFR was measured (mGFR) through iohexol or iothalamate clearance. A generalized linear model with sigmoidal nonlinear transfer function was used for equation development in the block-randomized development set. Covariates were selected in a data-driven fashion. The novel equation was assessed for bias, precision (mean ± SD), and accuracy (eGFR percentage within ±30% of mGFR, P30) in the validation set and compared with MDRD and CKD-EPI. Results: Median mGFR was 61 [44-81] ml/min per 1.73 m2. In order of importance, PENK, creatinine, and age were included, and sex or race did not improve performance. The PENK-based equation mean ± SD bias of the mGFR was 0.5 ± 15 ml/min per 1.73 m2, significantly less compared with MDRD (8 ± 17, P < 0.001) and 2009 CKD-EPI (5 ± 17, P < 0.001), not reaching statistical significance compared with 2021 CKD-EPI (1.3 ± 16, P = 0.06). The P30 accuracy of the PENK-based equation was 83%, significantly higher compared with MDRD (68%, P < 0.001) and 2009 CKD-EPI (76%, P < 0.001), similar to 2021 CKD-EPI (80%, P = 0.13). Conclusion: Overall, the PENK-based equation to assess eGFR performed better than most creatinine-based equations without using sex or race.

Severity of posttraumatic stress disorder, type 2 diabetes outcomes and all-cause mortality: A retrospective cohort study.

BACKGROUND: Some evidence suggests patients with comorbid PTSD and type 2 diabetes (T2D) have worse T2D outcomes than those with T2D alone. However, there is no evidence regarding PTSD severity and risk for starting insulin, hyperglycemia, microvascular complications, and all-cause mortality. METHODS: In this retrospective cohort study, Veterans Health Affairs (VHA) medical record data from fiscal year (FY) 2012 to FY2022 were used to identify eligible patients (n = 23,161) who had a PTSD diagnosis, ≥1 PTSD Checklist score, controlled T2D (HbA1c ≤ 7.5) without microvascular complications at baseline. PTSD Checklist for DSM-5 (PCL-5) scores defined mild, moderate, and severe PTSD. Competing risk and survival models estimated the association between PTSD severity and T2D outcomes before and after controlling for confounding. RESULTS: Most (70%) patients were ≥ 50 years of age, 88% were male, 64.2% were of white race and 17.1% had mild, 67.4% moderate and 15.5% severe PTSD. After control for confounding, as compared to mild PTSD, moderate (HR = 1.05; 95% CI:1.01-1.11) and severe PTSD (HR = 1.15; 95%CI:1.07-1.23) were significantly associated with increased risk for microvascular complication. Hyperarousal was associated with a 42% lower risk of starting insulin. Negative mood was associated with a 16% increased risk for any microvascular complication. Severe PTSD was associated with a lower risk for all-cause mortality (HR = 0.76; 95%CI:0.63-0.91). CONCLUSIONS: Patients with comorbid PTSD and T2D have an increased risk for microvascular complications. However, they have lower mortality risk perhaps due to more health care use and earlier chronic disease detection. PTSD screening among patients with T2D may be warranted.

Single Troponin Measurement to Rule Out Myocardial Infarction: JACC Review Topic of the Week.

The term "single-sample rule-out" refers to the ability of very low concentrations of high-sensitivity cardiac troponin (hs-cTn) on presentation to exclude acute myocardial infarction with high clinical sensitivity and negative predictive value. Observational and randomized studies have confirmed this ability. Some guidelines endorse use of a concentration of hs-cTn at the assay's limit of detection, while other studies have validated the use of higher concentrations, allowing this approach to identify a greater proportion of patients at low risk. In most studies, at least 30% of patients can be triaged with this approach. The concentration of hs-cTn varies according to the assay used and sometimes how regulations permit reporting. It is clear that patients need to be at least 2 hours from the onset of symptoms being evaluated. Caution is warranted, particularly with older patients, women, and patients with underlying cardiac comorbidities.

Use of the HEAR Score for 30-Day Risk-Stratification in Emergency Department Patients.

BACKGROUND: The 2021 American College of Cardiology/American Heart Association chest pain guidelines recommend risk scores such as HEAR (History, Electrocardiogram, Age, Risk factors) for short-term risk stratification, yet limited data exist integrating them with high-sensitivity cardiac troponin T (hs-cTnT). METHODS: Retrospective, multicenter (n = 2), observational, US cohort study of consecutive emergency department patients without ST-elevation myocardial infarction who had at least one hs-cTnT (limit of quantitation [LoQ] <6 ng/L, and sex-specific 99th percentiles of 10 ng/L for women and 15 ng/L for men) measurement on clinical indications in whom HEAR scores (0-8) were calculated. The composite major adverse cardiovascular event (MACE) outcome was 30-day prognosis. RESULTS: Among 1979 emergency department patients undergoing hs-cTnT measurement, 1045 (53%) were low risk (0-3), 914 (46%) intermediate risk (4-6), and 20 (1%) high risk (7-8) based on HEAR scores. HEAR scores were not associated with increased risk of 30-day MACE in adjusted analyses. Patients with quantifiable hs-cTnT (LoQ-99th) had an increased risk for 30-day MACE (3.4%) irrespective of HEAR scores. Those with serial hs-cTnT <99th percentile remained at low risk (range 0%-1.2%) across all HEAR score strata. Higher scores were not associated with long-term (2-year) events. CONCLUSIONS: HEAR scores are of limited value in those with baseline hs-cTnT 99th percentile to define short-term prognosis. In those with baseline quantifiable hs-cTnT within the reference range (<99th percentile), a higher risk (>1%) for 30-day MACE exists even in those with low HEAR scores. With serial hs-cTnT measurements, HEAR scores overestimate risk when hs-cTnT remains <99th percentile.