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.

Implications of Age for the Diagnostic and Prognostic Value of Cardiac Troponin T and I.

BACKGROUND: The influence of age on cardiac troponin is unclear and may vary between cardiac troponin T (cTnT) and I (cTnI). We aimed to compare the impact of age on the diagnostic and prognostic utility of cTnT and cTnI. METHODS: This Danish nationwide, register-based cohort study included patients with at least one cardiac troponin (cTn) measurement from 2009 through June 2022, stratified into decades of age. We used peak cTn concentration during admission, dichotomized as positive/negative and normalized to the 99th percentile. Receiver operating characteristics for myocardial infarction (MI) and logistic regression were used to estimate the odds ratio (OR) for mortality at 1 year. RESULTS: We included 541 817 patients; median age 66 years (interquartile range [IQR] 51-77) and 256 545 (47%) female. A total of 40 359 (7.4%) had an MI, and 59 800 (14.1%) patients died within 1 year of admission. The predictive ability of both cTns for MI were highest for patients 30 to 50 years. This was most pronounced for cTnT, the specificity of which fell from 83% among patients 40 to 49 years to 4% for patients ≥90 years. The prognostic ability of both cTns for 1-year mortality declined with age. cTnT had stronger prognostic ability for all age-groups; OR for a positive cTnT 28.4 (95% CI, 20.1-41.0) compared with 9.4 (95% CI, 5.0-16.7) for cTnI among patients <30 years. CONCLUSIONS: The predictive and prognostic ability of cTnT and cTnI declined with age. cTnT had a low specificity for MI in elderly patients. However, cTnT was the strongest prognostic marker among all age groups.

First-In-Man Trial of ß3-Adrenoceptor Agonist Treatment in Chronic Heart Failure: Impact on Diastolic Function.

ABSTRACT: Diastolic dysfunction (DD) in heart failure is associated with increased myocardial cytosolic calcium and calcium-efflux through the sodium-calcium exchanger depends on the sodium gradient. Beta-3-adrenoceptor (ß3-AR) agonists lower cytosolic sodium and have reversed organ congestion. Accordingly, ß3-AR agonists might improve diastolic function, which we aimed to assess. In a first-in-man, randomized, double-blinded trial, we assigned 70 patients with HF with reduced ejection fraction, New York Heart Association II-III, and left ventricular ejection fraction <40% to receive the ß3-AR agonist mirabegron (300 mg/day) or placebo for 6 months, in addition to recommended heart failure therapy. We performed echocardiography and cardiac computed tomography and measured N-terminal probrain natriuretic peptide at baseline and follow-up. DD was graded per multiple renowned algorithms. Baseline and follow-up data were available in 57 patients (59 ± 11 years, 88% male, 49% ischemic heart disease). No clinically significant changes in diastolic measurements were found within or between the groups by echocardiography (E/e' placebo: 13 ± 7 to 13 ± 5, P = 0.21 vs. mirabegron: 12 ± 6 to 13 ± 8, P = 0.74, between-group follow-up difference 0.2 [95% CI, -3 to 4], P = 0.89) or cardiac computed tomography (left atrial volume index: between-group follow-up difference 9 mL/m 2 [95% CI, -3 to 19], P = 0.15). DD gradings did not change within or between the groups following 2 algorithms ( P = 0.72, P = 0.75). N-terminal probrain natriuretic peptide remained unchanged in both the groups ( P = 0.74, P = 0.64). In patients with HF with reduced ejection fraction, no changes were identified in diastolic measurements, gradings or biomarker after ß3-AR stimulation compared with placebo. The findings add to the previous literature questioning the role of impaired Na + -Ca 2+ -mediated calcium export as a major culprit in DD. NCT01876433.

Hemodialysis and biomarkers of myocardial infarction - a cohort study.

OBJECTIVES: End-stage renal disease is associated with a high risk of cardiovascular disease. We compared the concentration and prognostic ability of high sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI) and cardiac myosin-binding protein C (cMyC) among stable hemodialysis patients. METHODS: Patients were sampled before and after hemodialysis. We measured hs-cTnI, hs-cTnT and cMyC and used Cox regressions to assess the association between quartiles of concentrations and all-cause mortality and a combination of cardiovascular events and all-cause mortality during follow-up. RESULTS: A total of 307 patients were included, 204 males, mean age 66 years (SD 14). Before dialysis, 299 (99 %) had a hs-cTnT concentration above the 99th percentile, compared to 188 (66 %) for cMyC and 35 (11 %) for hs-cTnI. Hs-cTnT (23 %, p<0.001) and hs-cTnI (15 %, p=0.049) but not cMyC (4 %, p=0.256) decreased during dialysis. Follow-up was a median of 924 days (492-957 days); patients in the 3rd and 4th quartiles of hs-cTnT (3rd:HR 3.0, 95 % CI 1.5-5.8, 4th:5.2, 2.7-9.8) and the 4th quartile of hs-cTnI (HR 3.8, 2.2-6.8) had an increased risk of mortality. Both were associated with an increased risk of the combined endpoint for patients in the 3rd and 4th quartiles. cMyC concentrations were not associated with risk of mortality or cardiovascular event. CONCLUSIONS: Hs-cTnT was above the 99th percentile in almost all patients. This was less frequent for hs-cTnI and cMyC. High cTn levels were associated with a 3-5-fold higher mortality. This association was not present for cMyC. These findings are important for management of hemodialysis patients.

Clinical implementation of partial oral treatment in infective endocarditis: the Danish POETry study.

BACKGROUND AND AIMS: In the Partial Oral Treatment of Endocarditis (POET) trial, stabilized patients with left-sided infective endocarditis (IE) were randomized to oral step-down antibiotic therapy (PO) or conventional continued intravenous antibiotic treatment (IV), showing non-inferiority after 6 months. In this study, the first guideline-driven clinical implementation of the oral step-down POET regimen was examined. METHODS: Patients with IE, caused by Staphylococcus aureus, Enterococcus faecalis, Streptococcus spp. or coagulase-negative staphylococci diagnosed between May 2019 and December 2020 were possible candidates for initiation of oral step-down antibiotic therapy, at the discretion of the treating physician. The composite primary outcome in patients finalizing antibiotic treatment consisted of embolic events, unplanned cardiac surgery, relapse of bacteraemia and all-cause mortality within 6 months. RESULTS: A total of 562 patients [median age 74 years (IQR, interquartile range, 65-80), 70% males] with IE were possible candidates; PO was given to 240 (43%) patients and IV to 322 (57%) patients. More patients in the IV group had IE caused by S. aureus, or had an intra-cardiac abscess, or a pacemaker and more were surgically treated. The primary outcome occurred in 30 (13%) patients in the PO group and in 59 (18%) patients in the IV group (P = .051); in the PO group, 20 (8%) patients died vs. 46 (14%) patients in the IV group (P = .024). PO-treated patients had a shorter median length of stay [PO 24 days (IQR 17-36) vs. IV 43 days (IQR 32-51), P < .001]. CONCLUSIONS: After clinical implementation of the POET regimen almost half of the possible candidates with IE received oral step-down antibiotic therapy. Patients in the IV group had more serious risk factors for negative outcomes. At 6-month follow-up, there was a numerically but not statistically significant difference towards a lower incidence of the primary outcome, a lower incidence of all-cause mortality and a reduced length of stay in the PO group. Due to the observational design of the study, the lower mortality may to some extent reflect selection bias and unmeasured confounding. Clinical implementation of PO regimens seemed feasible and safe.

Metabolomics of early myocardial ischemia.

INTRODUCTION: Diagnosing myocardial infarction is difficult during the initial phase. As, acute myocardial ischemia is associated with changes in metabolic pathways, metabolomics may provide ways of identifying early stages of ischemia. We investigated the changes in metabolites after induced ischemia in humans using nuclear magnetic resonance spectroscopy (NMR). METHODS: We included patients undergoing elective coronary angiography showing normal coronary arteries. These were randomized into 4 groups and underwent coronary artery occlusion for 0, 30, 60 or 90 s. Blood was collected over the next 3 h and analyzed using NMR. We used 2-way ANOVA of time from baseline- and treatment group to find metabolites that changed significantly following the intervention and principal component analysis (PCA) to investigate changes between the 90 s ischemia- and control groups at 15 and 60 min after intervention. RESULTS: We included 34 patients. The most pronounced changes were observed in the lipid metabolism where 38 of 112 lipoprotein parameters (34%) showed a significant difference between the patients exposed to ischemia and the control group. There was a decrease in total plasma triglycerides over the first hour followed by a normalization. The principal component analysis showed a effects of the treatment after just 15 min. These effects were dominated by changes in high-density lipoprotein. An increase in lactic acid levels was detected surprisingly late, 1-2 h after the ischemia. CONCLUSION: We investigated the earliest changes in metabolites of patients undergoing brief myocardial ischemia and found that ischemia led to changes throughout the lipid metabolism as early as 15 min post-intervention.

Waning humoral and cellular immunity after COVID-19 vaccination in patients with psoriasis treated with methotrexate and biologics: a cohort study.

BACKGROUND: mRNA-based COVID-19 vaccines have short- and long-term efficacy in healthy individuals, but their efficacy in patients with psoriasis receiving immunomodulatory therapy is less studied. OBJECTIVES: To investigate long-term immunity after COVID-19 vaccination in patients with psoriasis receiving immunomodulatory therapy. METHODS: A prospective cohort study including patients (n = 123) with psoriasis receiving methotrexate (MTX) or biologics and controls (n = 226). Only mRNA-based COVID-19 vaccines administered with standard intervals between doses were investigated. Markers of immunity included SARS-CoV-2 spike glycoprotein-specific IgG and IgA, neutralizing capacity, and interferon-γ release from T cells stimulated with peptides of the SARS-CoV-2 spike glycoprotein. RESULTS: The proportion of IgG responders was lower 6 months after vaccination in patients receiving anti-tumour necrosis factor (TNF) treatment compared with controls. Anti-TNF treatment was associated with lower IgG levels (ß = -0.82, 95% confidence interval -1.38 to -0.25; P = 0.001). The median neutralizing index was lower in the anti-TNF group [50% inhibition (interquartile range [IQR] 37-89)] compared with controls [98% inhibition (IQR 96-99)]; P < 0.001. Cellular responses were numerically lowest in the anti-TNF group. CONCLUSIONS: Treatment with anti-TNF has an impact on the immunity elicited by mRNA-based COVID-19 vaccination in patients with psoriasis, resulting in a faster waning of humoral and cellular markers of immunity; however, the clinical implications are unknown.

Humoral and cellular immune responses after three or four doses of BNT162b2 in patients with hematological malignancies.

OBJECTIVES: Initial responses to coronavirus disease 2019 vaccination are impaired in patients with hematological malignancies. We investigated immune responses after three or four doses of BNT162b2 in patients with myeloid and lymphoid malignancies compared to controls, and identified risk factors for humoral and cellular nonresponse 1 year after first vaccination. METHODS: In 407 hematological patients (45 myeloid, 362 lymphoid) and 98 matched controls, we measured immunoglobulin G (IgG) and neutralizing antibodies specific for the receptor-binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at baseline, 3 weeks, 2, 6, and 12 months, and interferon-γ release at 12 months. RESULTS: In patients with lymphoid malignancies, SARS-CoV-2 receptor-binding domain IgG concentration and mean neutralizing capacity was lower than in controls at all time points. A diagnosis of chronic lymphocytic B-cell leukemia (CLL) or lymphoma was associated with humoral nonresponse at 12 months compared to having multiple myeloma/amyloidosis (p < .001 and p = .013). Compared to controls, patients with lymphoid malignancies had increased risk of cellular nonresponse. A lymphoma diagnosis was associated with lower risk of cellular nonresponse compared to patients with multiple myeloma/amyloidosis, while patients with CLL had comparable response rates to patients with multiple myeloma/amyloidosis (p = .037 and p = .280). CONCLUSIONS: In conclusion, long-term humoral and cellular immune responses to BNT162b2 were impaired in patients with lymphoid malignancies.

Incidence of Positive Severe Acute Respiratory Syndrome Coronavirus Polymerase Chain Reaction After Coronavirus Disease 2019 Vaccination With up to 8 Months of Follow-up: Real-life Data From the Capital Region of Denmark.

BACKGROUND: Coronavirus disease 2019 (COVID-19) vaccines are implemented worldwide in efforts to curb the pandemic. This study investigates the risk of a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase polymerase chain reaction (RT-PCR) test following BNT162b2 vaccination in a large real-life population in Denmark. METHODS: Vaccination status and positive SARS-CoV-2 RT-PCR results from adults in the Capital Region of Denmark (n = 1 549 488) were obtained from national registries. PCR testing was free and widely available. The number of positive PCR tests per individual at risk was calculated as weekly rates. Time to positive PCR test was modelled using Kaplan-Meier methods and hazard ratios (HRs) were calculated using Cox regression. RESULTS: A total of 1 119 574 individuals received the first dose of BNT162b2 and 1 088 879 received a second dose of BNT162b2. Individuals were followed up to 8.7 months after first dose (median: 5.5 months; interquartile ratio: 4.1-8.7). Rates of PCR-confirmed SARS-CoV-2 infection 2-4 months after the second dose were 0.21, 0.33, and 0.36 per 1000 individuals per week at risk for July, August, and September, respectively. Four or more months after the second dose, the rates were 0.56, 0.76, and 0.53 per 1000 individuals per week at risk for July, August, and September, respectively. HR of SARS-CoV-2 infection after the second dose was 0.2 (95% confidence interval, .05-.48; P = .001) for individuals with 8 months' follow-up. CONCLUSIONS: Individuals who received 2 doses of the BNT162b2 COVID-19 vaccine had a low risk of breakthrough infection after up to 8 months of follow-up. However, there was a tendency toward higher rates with longer follow-up.

Humoral response to two doses of BNT162b2 vaccination in people with HIV.

BACKGROUND: People with HIV (PWH) are at increased risk of severe COVID-19. We aimed to determine humoral responses in PWH and controls who received two doses of BNT162b2. METHODS: In 269 PWH and 538 age-matched controls, we measured IgG and neutralizing antibodies specific for the receptor-binding domain of SARS-CoV-2 at baseline, 3 weeks and 2 months after the first dose of BNT162b2. RESULTS: IgG antibodies increased from baseline to 3 weeks and from 3 weeks to 2 months in both groups, but the concentrations of IgG antibodies were lower in PWH than that in controls at 3 weeks and 2 months (p = 0.025 and <0.001), respectively. The IgG titres in PWH with a humoral response at 2 months were 77.9% (95% confidence interval [62.5%-97.0%], age- and sex-adjusted p = 0.027) of controls. CONCLUSIONS: Reduced IgG antibody response to vaccination with BNT162b2 was found in PWH, and thus increased awareness of breakthrough infections in PWH is needed.

High incidence of discrepancies in new Siemens assay - a comparison of cardiac troponin I assays.

OBJECTIVES: Cardiac troponin (cTn) is the biochemical gold standard for diagnosing myocardial infarction (MI). We compared the Siemens ADVIA Centaur High-Sensitivity (hs-cTnI) assay with the Siemens Ultra assay (cTnI-U). METHODS: Over 3 months cTnI-U and hs-cTnI were measured simultaneously at Herlev-Gentofte Hospital. Acute myocardial injury was diagnosed using the 4th universal definition. Disputed cases were adjudicated using clinical data. We compared diagnostic accuracy using area under the curve (AUC) of the receiver operating characteristic. Outliers in between-assay differences were defined as a factor-5 difference and ≥1 measurement >40 ng/L. Patients with outlier differences were invited for re-sampling and tested with serial dilution and heterophilic blocking tubes. RESULTS: From the 18th January to the 20th April 2019, 4,369 samples on 2,658 patients were included. cTnI-U measured higher concentrations than hs-cTnI (mean 23%, -52-213%), resulting in a higher frequency of acute myocardial injury, 255 (9.6%) vs. 203 (7.6%), p<0.001. This remained significant after adjudication, 212 vs 197, p<0.001. AUC for the prediction of MI for was 0.963 for cTnI-U and 0.959 for hs-cTnI, p=0.001. Outlier differences were seen in 35 (1.2%) patients, primarily with elevated hs-cTnI (n=33, 94%). On two re-samplings (median 144 and 297 days since inclusion), 16 of 20 (80%) and 11 of 11 had sustained elevation of hs-cTnI. The samples showed no signs of heterophilic antibodies. CONCLUSIONS: Using hs-cTnI resulted in a subset of patients with large, discrepant elevations in concentration. These patients still had elevated hs-cTnI 6-10 months post admission but no heterophilic antibodies.

Accelerated treatment of endocarditis-The POET II trial: Rationale and design of a randomized controlled trial.

BACKGROUND: The optimal antibiotic treatment length for infective endocarditis (IE) is uncertain. International guidelines recommend treatment duration of up to 6 weeks for patients with left-sided IE but are primarily based on historical data and expert opinion. Efficacies of modern therapies, fast recovery seen in many patients with IE, and complications to long hospital stays challenge the rationale for fixed treatment durations in all patients. OBJECTIVE: The objective was to conduct a noninferiority randomized controlled trial (acronym POET II) investigating the safety of accelerated (shortened) antibiotic therapy as compared to standard duration in patients with left-sided IE. METHODS: The POET II trial is a multicenter, multinational, open-label, noninferiority randomized controlled trial. Patients with definite left-sided IE due to Streptococcus spp, Staphylococcus aureus, or Enterococcus faecalis will be eligible for enrolment. Each patient will be randomized to accelerated antibiotic treatment or standard-length treatment (1:1) following clinical stabilization as defined by clinical parameters, laboratory values, and transesophageal echocardiography findings. Accelerated treatment will be between 2 and 4 weeks, whereas standard-length treatment will be between 4 and 6 weeks, depending on microbiologic etiology, complications, need for valve surgery, and prosthetic versus native valve endocarditis. The primary outcome is a composite of all-cause mortality, unplanned cardiac surgery, relapse of bacteremia, or embolization within 6 months of randomization. CONCLUSIONS: The POET II trial will investigate the safety of accelerated antibiotic therapy for patients with left-sided IE caused by Streptococcus spp, Staphylococcus aureus, or Enterococcus faecalis. The results of the POET II trial will improve the evidence base of treatment recommendations, and clinical practice may be altered.

Risk assessment models for potential use in the emergency department have lower predictive ability in older patients compared to the middle-aged for short-term mortality - a retrospective cohort study.

BACKGROUND: Older patients is a complex group at increased risk of adverse outcomes compared to younger patients, which should be considered in the risk assessment performed in emergency departments. We evaluated whether the predictive ability of different risk assessment models for acutely admitted patients is affected by age. METHODS: Cohort study of middle-aged and older patients. We investigated the accuracy in discriminating between survivors and non-survivors within 7 days of different risk assessment models; a traditional triage algorithm, a triage algorithm with clinical assessment, vital signs, routine biomarkers, and the prognostic biomarker soluble urokinase plasminogen activator receptor (suPAR). RESULTS: The cohort included 22,653 (53.2%) middle-aged patients (age 40-69 years), and 19,889 (46.8%) older patients (aged 70+ years). Death within 7 days occurred in 139 patients (0.6%) in middle-aged patients and 596 (3.0%) of the older patients. The models based on vital signs and routine biomarkers had the highest area under the curve (AUC), and both were significantly better at discriminating 7-day mortality in middle-aged patients compared to older patients; AUC (95% CI): 0.88 (0.84-0.91), 0.75 (0.72-0.78), P < 0.01, and 0.86 (0.82-0.90), 0.76 (0.73-0.78), P < 0.001. In a subgroup of the total cohort (6.400 patients, 15.0%), the suPAR level was available. suPAR had the highest AUC of all individual predictors with no significant difference between the age groups, but further research in this biomarker is required before it can be used. CONCLUSION: The predictive value was lower in older patients compared to middle-aged patients for all investigated models. Vital signs or routine biomarkers constituted the best models for predicting 7-day mortality and were better than the traditional triage model. Hence, the current risk assessment for short-term mortality can be strengthened, but modifications for age should be considered when constructing new risk assessment models in the emergency department.

Sex and Population-Specific 99th Percentiles of Troponin for Myocardial Infarction in the Danish Population (DANSPOT).

BACKGROUND: Sex- and population-specific 99th percentiles of high-sensitivity cardiac troponin (hs-cTn) are recommended in guidelines although the evidence for a clinical utility is sparse. The DANSPOT trial will investigate the clinical effect of sex- and population-specific 99th percentiles of cTn. We report the 99th percentiles derived from this trial and their dependency on kidney function. METHODS: We used samples from healthy Danish blood donors and measured hemoglobin A1c, N-terminal pro-brain natriuretic peptide and creatinine, and calculated an estimated glomerular filtration rate (eGFR). We compared 2 cutoffs for the eGFR of healthy participants (60 vs 90 mL/min/1.73 m2). The cTn assays investigated were Siemens Atellica and Dimension Vista hs-cTnI, Abbott hs-cTnI, and Roche hs-cTnT. RESULTS: A total of 2287 participants were sampled, of which 71 (3.1%) were excluded due to a history of heart disease (n = 4), insufficient material (n = 7), or a screening biomarker (n = 60). Of the remaining 2216 participants, 1325 (59.8%) had an eGFR ≥90 mL/min/1.73 m2. Compared to a cutoff of 60 mL/min/1.73 m2 for eGFR, using 90 mL/min/1.73 m2 resulted in lower 99th percentiles for females; Siemens Vista (46 vs 70 ng/L), Abbott (14 vs 18 ng/L), and Roche cTnT (10 vs 13 ng/L), and decreased the number of measurements above the manufacturers' 99th percentiles for all assays. CONCLUSIONS: We present reference values for 4 cTn assays for eGFR cutoffs of 60 and 90 mL/min/1.73 m2. These cutoffs differ based on the eGFR threshold for inclusion indicating that any chosen cutoff is also valuable with moderately reduced kidney function.

DANSPOT: A Multicenter Stepped-Wedge Cluster-Randomized Trial of the Reclassification of Acute Myocardial Infarction: Rationale and Study Design.

BACKGROUND: Cardiac troponins are the preferred biomarkers for the diagnosis of acute myocardial infarction. Although sex-specific 99th percentile thresholds of troponins are recommended in international guidelines, the clinical effect of their use is poorly investigated. The DANSPOT Study (The Danish Study of Sex- and Population-Specific 99th percentile upper reference limits of Troponin) aims to evaluate the clinical effect of a prospective implementation of population- and sex-specific diagnostic thresholds of troponins into clinical practice. METHODS: This study is a nationwide, multicenter, stepped-wedge cluster-randomized trial of the implementation of population- and sex-specific thresholds of troponins in 22 of 23 clinical centers in Denmark. We established sex-specific thresholds for 5 different troponin assays based on troponin levels in a healthy Danish reference population. Centers will sequentially cross over from current uniform manufacturer-derived thresholds to the new population- and sex-specific thresholds. The primary cohort is defined as patients with symptoms suggestive of acute coronary syndrome having at least 1 troponin measurement performed within 24 hours of arrival with a peak troponin value between the current uniform threshold and the new sex-specific female and male thresholds. The study will compare the occurrence of the primary outcome, defined as a composite of nonfatal myocardial infarction, unplanned revascularization, and all-cause mortality within 1 year, separately for men and women before and after the implementation of the new sex-specific thresholds. CONCLUSIONS: The DANSPOT Study is expected to show the clinical effects on diagnostics, treatment, and clinical outcomes in patients with myocardial infarction of implementing sex-specific diagnostic thresholds for troponin based on a national Danish reference population. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05336435.

The Impact of Time between Booster Doses on Humoral Immune Response in Solid Organ Transplant Recipients Vaccinated with BNT162b2 Vaccines.

As solid organ transplant (SOT) recipients remain at risk of severe outcomes after SARS-CoV-2 infections, vaccination continues to be an important preventive measure. In SOT recipients previously vaccinated with at least three doses of BNT162b2, we investigated humoral responses to BNT162b2 booster doses. Anti-SARS-CoV-2 receptor binding domain (RBD) immunoglobulin G (IgG) was measured using an in-house ELISA. Linear mixed models were fitted to investigate the change in the geometric mean concentration (GMC) of anti-SARS-CoV-2 RBD IgG after vaccination in participants with intervals of more or less than six months between the last two doses of vaccine. We included 107 SOT recipients vaccinated with a BNT162b2 vaccine. In participants with an interval of more than six months between the last two vaccine doses, we found a 1.34-fold change in GMC per month (95% CI 1.25-1.44), while we found a 1.09-fold change in GMC per month (95% CI 0.89-1.34) in participants with an interval of less than six months between the last two vaccine doses, resulting in a rate ratio of 0.82 (95% CI 0.66 to 1.01, p = 0.063). In conclusion, the administration of identical COVID-19 mRNA vaccine boosters within six months to SOT recipients may result in limited humoral immunogenicity of the last dose.

Causes of death among non-urgent patients in the emergency department who die within 30 days.

INTRODUCTION: Patients triaged as non-urgent in the emergency department constitute a diverse group with a low mortality rate assumed to be able to wait three hours for a physician. Little is known about the causes of death of non-urgent patients who die shortly after admission. We examined whether deaths among non-urgent patients were preventable. METHOD: Using data from the Copenhagen Triage Algorithm Study, we conducted a review of electronic medical records of all patients triaged as non-urgent who died within 30 days of presentation and constructed short summaries. These summaries were reviewed by two senior physicians who determined whether each death was expected or unexpected. The unexpected deaths were further assessed as unrelated or related to admission and if related as preventable or unpreventable. Any disagreements were settled by a third senior physician. RESULTS: Among the patients triaged as non-urgent, 335 of 14,655 (2%) died within 30 days. When comparing biomarkers and age, the non-urgent patients resembled the patients in other triage categories who died within 30 days. Most deaths were expected or not preventable (96%). The preventable deaths (n = 13, 4%) were among older patients with comorbidities. Causes of death were sudden cardiac arrest (n = 3), infection (n = 4), kidney failure (n = 1), electrolyte derangement (n = 1) and unknown (n = 4). CONCLUSION: Preventable deaths among non-urgent patients were rare and no overrepresentation was observed of specialties or diseases. FUNDING: Trygfonden. CLINICALTRIALS: gov:NCT02698319.

Non-cardiac causes of troponin elevation.

With the increased sensitivity of the newest cardiac troponin assays, the risk of false positive cardiac troponin measurements has also increased. As summarised in this review, there are multiple possible causes of cardiac troponin release including several non-cardiac illnesses, particularly kidney disease. Further, there is a risk of analytical interference in which case repeated measurements with a different assay is a good tool. When there is a discrepancy between troponin measurement and clinical presentation of the patient, the clinician should consider the possibility of analytical interference.