Doppler Ultrasound Flow Reversal in the Superior Sagittal Sinus to Detect Cerebral Venous Congestion in Vein of Galen Malformation

BACKGROUND AND PURPOSE

Vein of Galen malformation is a rare congenital cerebrovascular malformation. In affected patients, increased cerebral venous pressure constitutes an important etiologic factor for the development of brain parenchymal damage. The aim of this study was to investigate the potential of serial cerebral venous Doppler measurements to detect and monitor increased cerebral venous pressure.

MATERIALS AND METHODS

This was a retrospective monocentric analysis of ultrasound examinations within the first 9 months of life in patients with vein of Galen malformation admitted at <28 days of life. Categorization of perfusion waveforms in the superficial cerebral sinus and veins into 6 patterns was based on antero- and retrograde flow components. We performed an analysis of flow profiles across time and correlation with disease severity, clinical interventions, and congestion damage on cerebral MR imaging.

RESULTS

The study included 44 Doppler ultrasound examinations of the superior sagittal sinus and 36 examinations of the cortical veins from 7 patients. Doppler flow profiles before interventional therapy correlated with disease severity determined by the Bicêtre Neonatal Evaluation Score (Spearman ρ = -0.97, P = < .001). At this time, 4 of 7 patients (57.1%) showed a retrograde flow component in the superior sagittal sinus, whereas after embolization, none of the 6 treated patients presented with a retrograde flow component. Only patients with a high retrograde flow component (equal or more than one-third retrograde flow, n = 2) showed severe venous congestion damage on cerebral MR imaging.

CONCLUSIONS

Flow profiles in the superficial cerebral sinus and veins appear to be a useful tool to noninvasively detect and monitor cerebral venous congestion in vein of Galen malformation.

Machine learning for diagnosis of myocardial infarction using cardiac troponin concentrations

Although guidelines recommend fixed cardiac troponin thresholds for the diagnosis of myocardial infarction, troponin concentrations are influenced by age, sex, comorbidities and time from symptom onset. To improve diagnosis, we developed machine learning models that integrate cardiac troponin concentrations at presentation or on serial testing with clinical features and compute the Collaboration for the Diagnosis and Evaluation of Acute Coronary Syndrome (CoDE-ACS) score (0-100) that corresponds to an individual's probability of myocardial infarction. The models were trained on data from 10,038 patients (48% women), and their performance was externally validated using data from 10,286 patients (35% women) from seven cohorts. CoDE-ACS had excellent discrimination for myocardial infarction (area under curve, 0.953; 95% confidence interval, 0.947-0.958), performed well across subgroups and identified more patients at presentation as low probability of having myocardial infarction than fixed cardiac troponin thresholds (61 versus 27%) with a similar negative predictive value and fewer as high probability of having myocardial infarction (10 versus 16%) with a greater positive predictive value. Patients identified as having a low probability of myocardial infarction had a lower rate of cardiac death than those with intermediate or high probability 30 days (0.1 versus 0.5 and 1.8%) and 1 year (0.3 versus 2.8 and 4.2%; P < 0.001 for both) from patient presentation. CoDE-ACS used as a clinical decision support system has the potential to reduce hospital admissions and have major benefits for patients and health care providers.

Rapid Rule-Out of Myocardial Infarction Using a Single High-Sensitivity Cardiac Troponin I Measurement Strategy at Presentation to the Emergency Department: The SAFETY Study

BACKGROUND

Our study addressed the diagnostic performance of the Atellica® IM High-Sensitivity Troponin I (hs-cTnI) assay for the rapid rule-out of myocardial infarction (MI) using a single hs-cTnI measurement at presentation in patients presenting to a US emergency department (ED).

METHODS

This was a prospective, observational, cohort study of consecutive ED patients with suspected acute coronary syndrome, using 12-lead electrocardiogram and serial hs-cTnI measurements ordered on clinical indication (SAFETY, NCT04280926). ST-segment elevation MI patients were excluded. The optimal threshold required a sensitivity ≥99% and a negative predictive value (NPV) ≥99.5% for MI during index hospitalization as primary outcome. Type 1 MI (T1MI), myocardial injury, and 30-day adverse events were considered secondary outcomes. Event adjudications were established using the hs-cTnI assay used in clinical care.

RESULTS

In 1171 patients, MI occurred in 97 patients (8.3%), 78.3% of which were type 2 MI. The optimal rule out hs-cTnI threshold was <10 ng/L, which identified 519 (44.3%) patients as low risk at presentation, with sensitivity of 99.0% (95% CI, 94.4-100) and NPV of 99.8% (95% CI, 98.9-100). For T1MI, sensitivity was 100% (95% CI, 83.9-100) and NPV 100% (95% CI, 99.3-100). Regarding myocardial injury, the sensitivity and NPV were 99.5% (95% CI, 97.9-100) and 99.8% (95% CI, 98.9-100), respectively. For 30-day adverse events, sensitivity was 96.8% (95% CI, 94.3-98.4) and NPV 97.9% (95% CI, 96.2-98.9).

CONCLUSIONS

A single hs-cTnI measurement strategy enabled the rapid identification of patients at low risk of MI and 30-day adverse events, allowing potential discharge early after ED presentation.

CLINICALTRIALS.GOV REGISTRATION NUMBER

NCT04280926.

Analytical performance comparing siemens whole blood point of care Atellica VTLi to the central laboratory plasma Atellica IM high-sensitivity cardiac troponin I assays

INTRODUCTION

This study examined the analytical performance of a whole blood (WB) point of care (POC) hs-cTnI assay compared to a plasma central laboratory hs-cTnI assay in patients presenting with ischemic symptoms to a US emergency department.

METHODS

Fresh WB specimens collected at 0 and 2 h from 1089 consecutive patients (2152 total from 1076 matched specimens) were analyzed for hs-cTnI using WB on POC Siemens Atellica VTLi assay and plasma on central laboratory Siemens Atellica IM assay. Concordances were determined based on concentrations ranging from < limit of detection (LoD), LoD to overall and sex specific 99th percentiles from both the IFCC manufacturer package inserts and Universal Sample Bank (USB) data, and > 99th percentiles. Method comparisons were calculated using Passing Bablok regression and Bland Altmann plots, and linear regression determined by Pearson correlation coefficient.

RESULTS

Baseline concentration comparisons showed: POC VTLi < LoD 4-5 %, ≥ LoD 95 %; Atellica IM < LoD 5-7 %, and ≥ LoD 94-95 %. From the 2152 paired 0 and 2-hour samples, based on 99th percentiles, overall concordance was 91-92 % (kappa 0.72-0.77) and discordance 8 %. Passing Bablok regression analysis using 1924 specimens between LoD to 500 ng/L showed: slopes 0.469-0.490; y-intercepts 1.753-2.028; r values 0.631-0.817. Pearson correlation coefficient showed moderate to strong correlation strength, even with up to 53 % cTnI concentrations variance (Passing Bablok slopes) vs 27.0-40.1 % (Bland-Altmann plots).

CONCLUSIONS

Up to 95 % of measured samples were > LoD for both the POC (Atellica VTLi) and central laboratory (Atellica IM) hs-cTnI assays. Moderate to strong concordance and correlation were observed between assays, despite up to 53 % variances in cTnI concentration.

Single High-Sensitivity Point-of-Care Whole-Blood Cardiac Troponin I Measurement to Rule Out Acute Myocardial Infarction at Low Risk

BACKGROUND

High-sensitivity cardiac troponin (hs-cTn) laboratory assays are used to rule out myocardial infarction (MI) on presentation, but prolonged result turnaround times can delay patient management. Our primary aim was to identify patients at low risk of index MI using a rapid point-of-care (POC) whole-blood hs-cTnI assay at presentation with potential early patient discharge.

METHODS

Consecutive patients presenting to the emergency department from 2 prospective observational studies with suspected acute coronary syndrome were enrolled. A POC hs-cTnI assay (Atellica VTLi) threshold using whole blood at presentation, which resulted in a negative predictive value of ≥99.5% and sensitivity of >99% for index MI, was derived (SEIGE [Safe Emergency Department Discharge Rate]) and validated with plasma (SAMIE [Suspected Acute Myocardial Infarction in Emergency]). Event adjudications were established with hs-cTnI assay results from routine clinical care. The primary outcome was MI at 30 days.

RESULTS

A total of 1086 patients (8.1% with MI) were enrolled in a US derivation cohort (SEIGE) and 1486 (5.5% MI) in an Australian validation cohort (SAMIE). A derivation whole-blood POC hs-cTnI concentration of <4 ng/L provided a sensitivity of 98.9% (95% CI, 93.8%-100%) and negative predictive value of 99.5% (95% CI, 97.2%-100%) for ruling out MI. In the validation cohort, the sensitivity was 98.8% (95% CI, 93.3%-100%), and negative predictive value was 99.8% (95% CI, 99.1%-100%); 17.8% and 41.8%, respectively, were defined as low risk for discharge. The 30-day adverse cardiac events were 0.1% (n=1) for SEIGE and 0.8% (n=5) for SAMIE.

CONCLUSIONS

A POC whole-blood hs-cTnI assay permits accessible, rapid, and safe exclusion of MI and may expedite discharge from the emergency department.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04772157. URL: https://www.australianclinicaltrials.gov.au/anzctr_feed/form; Unique identifier: 12621000053820.

Review: Bioavailability of trace elements in farm animals: definition and practical considerations for improved assessment of efficacy and safety

Currently, the authorisation procedure of trace elements as feed additives in the European Union according to Regulation (EC) No. 1831/2003 does not consider the bioavailability of trace element sources. This manuscript provides framework conditions for in vivo experiments that aim to estimate differences in the relative bioavailability between supplements of essential trace elements. Framework conditions encompass necessary technical information on the test substance, the experimental design and diet composition as well as the suitability of status parameters that allow for relative comparisons of regression variables. This manuscript evolves recommendations for researchers to conduct solid and reliable experiments on the matter as well as decision makers to interpret the value of studies submitted with authorisation applications regarding a certain trace element supplement.

Observational Study of Receptor Binding Domain Spike Antibody Responses to 3 SARS-CoV-2 Vaccinations in Noninfected Subjects: Parallel Neutralizing Antibody and Cardiac Troponin I and T Observations

Background

Our goals were to demonstrate receptor binding domain spike 1 (RBD S1) protein antibody (Ab) kinetic responses to multiple vaccines over approximately 180 days, neutralizing Ab effectiveness, and high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) responses in postvaccinated, non-SARS-CoV-2–infected subjects.

Methods

Blood specimens were collected pre- and postvaccinations from seronegative subjects. RDB S1 Abs were measured by the novel Qorvo Biotechnologies Omnia platform. Neutralizing Abs and hs-cTnI and hs-cTnT were measured on the ET Healthcare Pylon 3D.

Results

Two-dose vaccines (Pfizer, Moderna) had peak RBD S1 Ab concentrations about 45 to 55 days after both doses and showed declines over the next 50 to 70 days. The Janssen vaccine showed lower RBD S1 Ab peak concentrations, continued to increase over time, and plateaued after 60 days. There was strong neutralizing Ab response post vaccinations, with only 3 specimens, shortly before and shortly after vaccination, not showing a response. Specimens showed no hs-cTnI (all < 3 ng/L) and hs-cTnT (all < 6 ng/L) increases or changes over time.

Conclusions

We demonstrate in seronegative SARS-CoV-2 subjects that Pfizer and Moderna vaccinations provide strong, neutralizing RBD S1 Ab effectiveness, based on 2 different assays after 2 doses, with the Janssen single-dose vaccine showing a lower RBD S1 Ab response over 4 to 6 months. No myocardial injury was associated with the Pfizer postvaccination. The Qorvo Biotechnologies RBD S1 Ab assay measured on the Omnia platform has potential as a point-of-care platform.

Diagnostic performance of a rapid, novel, whole blood, point of care high-sensitivity cardiac troponin I assay for myocardial infarction

BACKGROUND

We evaluated the diagnostic performance of a whole blood, point of care (POC) high-sensitivity cardiac troponin I (hs-cTnI) assay for myocardial infarction (MI) compared to central laboratory assays.

METHODS

Consecutive patients presenting to the emergency department with symptoms of ischemia were studied. Serial hs-cTnI testing was based on clinical indication at presentation. Parallel measurements were made using fresh whole blood on Siemens Atellica VTLi POC assay, EDTA plasma on Abbott ARCHITECT i2000 used in practice, and heparin plasma on Siemens Atellica. MI was determined according to the Fourth Universal Definition of MI using 99th percentiles. Sensitivities and negative predictive values (NPV) were calculated using 99th percentile URLs.

RESULTS

1089 Patients, 418 females and 671 males, were enrolled. There were 91 (8.4%) MIs. At baseline (0 h), POC hs-cTnI assay had a sensitivity of 65.7% (95% CI 47.8-80.9) for females and 67.9% (54.0-79.7) for males and NPV of 96.4% (93.9-98.1) for females and 96.7% (94.9-98.0) for males. At 2 h, sensitivity improved to 82.9% (66.4-93.4) for females and 80.4% (67.6-89.8) for males, while NPV improved to 98.2% (96.1-99.3) and 97.9% (96.3-99.0), respectively. For central laboratory assays, comparable diagnostics were observed at 2 h: females - sensitivity 94.3% (80.8-99.3) for ARCHITECT and 79.4% (62.1-91.3) for Atellica, and NPV 99.3% (97.6-99.9) and 98.0% (95.8-99.2), respectively; males - sensitivity 87.5% (75.9-94.8) for ARCHITECT and 80.4% (67.6-89.8) for Atellica, NPVs of 98.7% (97.3-99.5) and 97.9% (96.3-99.0), respectively.

CONCLUSIONS

The POC, whole blood Atellica VTLi hs-cTnI assay demonstrated comparable diagnostic accuracy for MI to central laboratory assays using 99th percentiles.

Determination of sex-specific 99th percentile upper reference limits for a point of care high sensitivity cardiac troponin I assay

OBJECTIVES

High sensitivity (hs) cardiac troponin (cTn) assays are defined per the IFCC Committee on Clinical Application of Cardiac Biomarker (C-CB) by the ability to measure ≥ 50% of concentrations greater than the limit of detection (LoD) with an impression of ≤10% at sex-specific 99th percentiles. Our study determined the sex-specific 99th percentile upper reference limits for males and females utilizing heparinized plasma from AACC universal sample bank for the Siemens point of care (POC) Atellica^® VTLi hs-cTnI immunoassay.

METHODS

Apparently healthy subjects, included overall 693, males 363, and females 330, following exclusionary surrogate biomarker use of hemoglobin A_1c, NT-proBNP, and eGFR, along with statin medication. hs-cTnI was measured in a central laboratory, on multiple POC Atellica^® VTLi immunoassay analyzers. The LoD was 1.24 ng/L and the 10%CV concentration was 6.7 ng/L. 99th percentile URLs were determined by the nonparametric (NP) method.

RESULTS

Histograms of the hs-cTnI concentrations (ng/L) for males and females were used to visualize the distributions and concentrations in men and women and differed significantly (pre- and post-exclusion, both p <0.001). 99th percentile URLs were: overall 23 ng/L (90% CI 20-32 ng/L); male 27 ng/L (CI 21-37 ng/L); female 18 ng/L (CI 9-78 ng/L). The percentages of subjects having a measurable concentration ≥ the LoD were: overall 83.7%, male 87.3%, female 79.7%.

CONCLUSIONS

Our findings show the novel POC Atellica^® VTLi hs-cTnI assay meets the designation of a 'high-sensitivity' assay using heparinized plasma.

Independent and combined effects of biotin and hemolysis on high-sensitivity cardiac troponin assays

OBJECTIVES

This study compared the independent and combined effects of hemolysis and biotin on cardiac troponin measurements across nine high-sensitivity cardiac troponin (hs-cTn) assays.

METHODS

Parallel cTn measurements were made in pooled lithium heparin plasma spiked with hemolysate and/or biotin using nine hs-cTn assays: Abbott Alinity, Abbott ARCHITECT i2000, Beckman Access 2, Ortho VITROS XT 7600, Siemens Atellica, Siemens Centaur, Siemens Dimension EXL cTnI, and two Roche Cobas e 411 Elecsys Troponin T-hs cTnT assays (outside US versions, with and without increased biotin tolerance). Absolute and percent cTn recovery relative to two baseline concentrations were determined in spiked samples and compared to manufacturer's claims.

RESULTS

All assays except the Ortho VITROS XT 7600 showed hemolysis and biotin interference thresholds equivalent to or greater than manufacturer's claims. While imprecision confounded analysis of Ortho VITROS XT 7600 data, evidence of biotin interference was lacking. Increasing biotin concentration led to decreasing cTn recovery in three assays, specifically both Roche Cobas e 411 Elecsys Troponin T-hs assays and the Siemens Dimension EXL. While one of the Roche assays was the most susceptible to biotin among the nine studied, a new version showed reduced biotin interference by approximately 100-fold compared to its predecessor. Increasing hemolysis also generally led to decreasing cTn recovery for susceptible assays, specifically the Beckman Access 2, Ortho VITROS XT 7600, and both Roche Cobas e 411 Elecsys assays. Equivalent biotin and hemolysis interference thresholds were observed at the two cTn concentrations considered for all but two assays (Beckman Access 2 and Ortho VITROS XT 7600). When biotin and hemolysis were present in combination, biotin interference thresholds decreased with increasing hemolysis for two susceptible assays (Roche Cobas e 411 Elecsys and Siemens Dimension EXL).

CONCLUSIONS

Both Roche Cobas e 411 Elecsys as well as Ortho VITROS XT assays were susceptible to interference from in vitro hemolysis at levels routinely encountered in clinical laboratory samples (0-3 g/L free hemoglobin), leading to falsely low cTn recovery up to 3 ng/L or 13%. While most assays are not susceptible to biotin at levels expected with over-the-counter supplementation, severely reduced cTn recovery is possible at biotin levels of 10-2000 ng/mL (41-8,180 nmol/L) for some assays. Due to potential additive effects, analytical interferences should not be considered in isolation.

Sex-Specific 99th Percentile Upper Reference Limits for High Sensitivity Cardiac Troponin Assays Derived Using a Universal Sample Bank

BACKGROUND

How to select healthy reference subjects in deriving 99th percentiles for cardiac troponin assays still needs to be clarified. To assist with global implementation of high sensitivity (hs)-cardiac troponin (cTn) I and hs-cTnT assays in clinical practice, we determined overall and sex-specific 99th percentiles in 9 hs-cTnI and 3 hs-cTnT assays using a universal sample bank (USB).

METHODS

The Universal Sample Bank (USB) comprised healthy subjects, 426 men and 417 women, screened using a health questionnaire. Hemoglobin A1c (>URL 6.5%), NT-proBNP (>URL 125 ng/L) and eGFR (<60 mL/min), were used as surrogate biomarker exclusion criteria along with statin use. 99th percentiles were determined by nonparametric, Harrell--Davis bootstrap, and robust methods.

RESULTS

Subjects were ages 19 to 91 years, Caucasian 58%, African American 27%, Pacific Islander/Asian 11%, other 4%, Hispanic 8%, and non-Hispanic 92%. The overall and sex-specific 99th percentiles for all assays, before and after exclusions (n = 694), were influenced by the statistical method used, with substantial differences noted between and within both hs-cTnI and hs-cTnT assays. Men had higher 99th percentiles (ng/L) than women. The Roche cTnT and Beckman and Abbott cTnI assays (after exclusions) did not measure cTn values at ≥ the limit of detection in ≥50% women.

CONCLUSIONS

Our findings have important clinical implications in that sex-specific 99th percentiles varied according to the statistical method and hs-cTn assay used, not all assays provided a high enough percentage of measurable concentrations in women to qualify as a hs-assay, and the surrogate exclusion criteria used to define normality tended to lower the 99th percentiles.

Application of the World Café method to discuss the efficiency of African swine fever control strategies in European wild boar (Sus scrofa) populations

In the current epidemic of African swine fever (ASF) in Europe, the maintenance and spread of the disease among wild boar populations remains the most important epidemiological challenge. Affected and at-risk countries have addressed this situation using a diversity of wild boar management methods with varying levels of success. The methods applied range from conventional animal disease intervention measures (zoning, stakeholder awareness campaigns, increased surveillance and biosecurity measures) to measures aimed at reducing wild boar population movements (fencing and baiting/feeding) or population numbers (intensive hunting). To assess the perceived efficiency and acceptance of such measures in the context of a focal introduction of ASF, the authors organised a participatory workshop inviting experts from the fields of wildlife management, wild boar ecology, sociology, epidemiology and animal disease management to discuss the advantages and disadvantages of various control approaches. The discussions between professionals from different countries took place using the World Café method. This paper documents the World Café method as a tool for increasing the level of participation in multi-stakeholder group discussions, and describes the outputs of the workshop pertaining to the control measures. In summary, the World Café method was perceived as an efficient tool for quickly grasping comprehensive perspectives from the professionals involved in managing ASF and wild boar populations, while promoting engagement in multi-disciplinary discussions. The exercise achieved a good overview of the perceived efficiency and applicability of the different control methods and generated useful recommendations for ASF control in wild boar populations in Europe.

Function Space Optimization: A Symbolic Regression Method for Estimating Parameter Transfer Functions for Hydrological Models

Estimating parameters for distributed hydrological models is a challenging and long studied task. Parameter transfer functions, which define model parameters as functions of geophysical properties of a catchment, might improve the calibration procedure, increase process realism, and can enable prediction in ungauged areas. We present the function space optimization (FSO), a symbolic regression method for estimating parameter transfer functions for distributed hydrological models. FSO is based on the idea of transferring the search for mathematical expressions into a continuous vector space that can be used for optimization. This is accomplished by using a text generating neural network with a variational autoencoder architecture that can learn to compress the information of mathematical functions. To evaluate the performance of FSO, we conducted a case study using a parsimonious hydrological model and synthetic discharge data. The case study consisted of two FSO applications: single-criteria FSO, where only discharge was used for optimization, and multicriteria FSO, where additional spatiotemporal observations of model states were used for transfer function estimation. The results show that FSO is able to estimate transfer functions correctly or approximate them sufficiently. We observed a reduced fit of the parameter density functions resulting from the inferred transfer functions for less sensitive model parameters. For those it was sufficient to estimate functions resulting in parameter distributions with approximately the same mean parameter values as the real transfer functions. The results of the multicriteria FSO showed that using multiple spatiotemporal observations for optimization increased the quality of estimation considerably.

Pathogen-specific antibody profiles in patients with severe systemic infections

Infections are often caused by pathobionts, endogenous bacteria that belong to the microbiota. Trauma and surgical intervention can allow bacteria to overcome host defences, ultimately leading to sepsis if left untreated. One of the main defence strategies of the immune system is the production of highly specific antibodies. In the present proof-of-concept study, plasma antibodies against 9 major pathogens were measured in sepsis patients, as an example of severe systemic infections. The binding of plasma antibodies to bacterial extracellular proteins was quantified using a semi-automated immunoblot assay. Comparison of the pathogen-specific antibody levels before and after infection showed an increase in plasma IgG in 20 out of 37 tested patients. This host-directed approach extended the results of pathogen-oriented microbiological and PCR diagnostics: a specific antibody response to additional bacteria was frequently observed, indicating unrecognised poly-microbial invasion. This might explain some cases of failed, seemingly targeted antibiotic treatment.

Clinical Evaluation of a New Point-of-Care System for Chemistry Panel Testing

Background

GEM Premier ChemSTAT™ is a point-of-care (POC) system that measures Na+, K+, Ca++, Cl−, glucose, hematocrit, creatinine, blood urea nitrogen (BUN), tCO2, pH, pCO2, and lactate from a single whole blood specimen, providing rapid results in POC settings such as the emergency department (ED). Accurate measurements of creatinine in whole blood and reporting of estimated glomerular filtration rate (eGFR) can minimize adverse effects of contrast-induced nephropathy.

Methods

Heparinized whole blood specimens from the ED were analyzed on the ChemSTAT by POC staff. Method comparison was performed against the cobas Integra c501 for creatinine, BUN, and tCO2, and against the GEM Premier 4000 for all other analytes. Precision was conducted with whole blood specimens assayed in triplicate over 6 days. Creatinine results from whole blood and plasma were used for eGFR, by isotope dilution mass spectrometry-traceable Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration equations, and eGFR concordance was assessed.

Results

Creatinine, BUN, and tCO2 correlated well with plasma samples on the cobas, and all other analytes correlated well with whole blood specimens on the GEM Premier 4000 across the tested sample ranges. The regression slope was 0.951 to 1.047, along with a correlation coefficient (r) of ≥0.982 for all analytes. The pooled within-sample precision was 0% to 2.5% for all analytes.

Conclusions

ChemSTAT demonstrated a strong correlation with the comparative methods and excellent precision. The system's analytical performance and continuous quality management make it suitable for use in the ED to provide rapid reliable test results, which could minimize the time to treatment and improve ED efficiency.

P3608Long-term mortality and mode of death among patients with type 1 and 2 myocardial infarction

Background

Few studies address long-term outcomes among patients with type 2 myocardial infarction (T2MI). It has been suggested that patients with T2MI with concomitant stable ischemic heart disease are at higher-risk.

Purpose

Our goals were two-fold. First, to examine 5-year mortality rates and mode of death among patients with type 1 (T1MI) and T2MI. Second, to evaluate the prognostic impact of coronary artery disease (CAD) on long-term outcomes among patients with T2MI.

Methods

Post-hoc analysis of UTROPIA (NCT02060760), a prospective, observational cohort study involving 1,640 consecutive emergency department patients with serial cardiac troponin (cTn) I measurements obtained on clinical indication. 5-year death rates, including mode of death, were examined among patients with T1MI and T2MI. CAD was defined as the presence of any of the following: history of CAD, prior MI, prior coronary artery bypass graft surgery, prior percutaneous coronary intervention, prior coronary stenting, or documented CAD (≥50%) on index admission angiography.

Results

Among 1640 patients, acute MI was diagnosed in 217 patients, including 77 (4.7%) classified as T1MI and 140 (8.5%) as T2MI. At 5-years, 23% (n=18) of patients with T1MI had died, with 61% (n=11) categorized as cardiac deaths. For T2MI, 37% (n=52) had died at 5-years, with 36% (n=19) categorized as cardiac deaths. Patients with T2MI had a higher 5-year mortality than T1MI (37% vs 23%, p=0.038) (Figure, Panel A), with T2MI more likely than T1MI to die from non-cardiac causes (64% vs. 39%, p=0.04). CAD was present in 22% (n=31) of patients with T2MI and associated with worse outcomes (p=0.0496) (Figure, Panel B).

Conclusion

T2MI has worse long term outcomes than T1MI. The predominant mode of death among patients with T2MI is non-cardiac. However, approximately 40% of deaths are cardiac. Further, we confirm the presence of CAD identifies a subset of patients with T2MI at high-risk.

Acknowledgement/Funding

Abbott Diagnostics and Hennepin Healthcare Research Institute (formerly MMRF)

P851Incidence and prognostic impact of acute infection among patients with type 1 and 2 myocardial infarction

Background

The incidence and impact of acute infection among patients with type 1 (T1MI) and 2 myocardial infarction (T2MI) is not well known. Inflammation and increased procoagulant activity can lead to T1MI, whereas cytokine release can cause hemodynamic alterations affecting myocardial oxygen consumption and contribute to T2MI.

Purpose

Determine the incidence and prognostic impact of acute infection among patients with T1MI and T2MI.

Methods

Post-hoc analysis of UTROPIA (NCT02060760), a prospective, observational cohort study involving 1,640 consecutive emergency department patients with serial cardiac troponin (cTn) I measurements obtained on clinical indication. The incidence of acute infection, antibiotic use, and/or laboratory evidence of infection were examined among patients with T1MI and T2MI. 5-year cumulative survival curves were plotted using the Kaplan-Meier method, frequencies were compared via Chi-Square, and a multivariate cox-proportional hazards model was used to assess the impact of infection on mortality.

Results

Among 217 patients with acute MI (T1MI, n=77 and T2MI, n=140), acute infection occurred in 63 (29%) of patients. Acute infection was more common in patients with T2MI than T1MI (35% vs. 18%, p=0.009). The predominant source of infection was pneumonia (59%), followed by urinary tract infections (11%). Patients with T2MI were also more likely than T1MI to have sepsis (11% vs. 1%, p=0.012), bacteremia (30% vs. 18%, p=0.057), and antibiotic use (35% vs. 17%, p=0.005). At 5-years, patients with acute MI and acute infection had a higher mortality rate than patients without infection (49% vs. 25%, p=0.0006) (Figure). Among the 31 deaths in MI patients with acute infection, most deaths were non-cardiac (65%) and occurred in those with T2MI (77%). Following adjustment for age, sex, and comorbidities in a Cox proportional hazards model, acute infection was an independent predictor of death (hazard ratio: 2.2, 95% CI: 1.3–3.5, p=0.0016).

Conclusion

Acute infection occurs in almost a third of patients that are diagnosed with acute MI during the index hospitalization. Most infections are due to pneumonia and occur most often in patients classified as having T2MI. Acute infection is an independent risk factor for 5-year mortality, with nearly half of all patients with acute MI in whom concomitant acute infection is present during the index hospitalization dead at 5-years. Most deaths are non-cardiac and the vast majority occur in patients with T2MI.

Acknowledgement/Funding

Abbott Diagnostics and Hennepin Healthcare Research Institute (formerly MMRF)e

Appropriateness of Cardiac Troponin Testing: Insights from the Use of TROPonin In Acute coronary syndromes (UTROPIA) Study

OBJECTIVE

Our objective was to examine the appropriateness of cardiac troponin (cTn) testing among patients with cTn increases.

METHODS

This is a planned secondary analysis of the Use of TROPonin In Acute coronary syndromes (UTROPIA, NCT02060760) observational cohort study. Appropriateness of cTn testing was adjudicated for emergency department patients with cTn increases >99^th percentile and analyzed using both contemporary and high-sensitivity (hs) cTnI assays according to sub-specialty, diagnoses, and symptoms.

RESULTS

Appropriateness was determined from 1272 and 1078 adjudication forms completed for 497 and 422 patients with contemporary and hs-cTnI increases, respectively. Appropriateness of cTnI testing across adjudication forms was 71.5% and 72.0% for cTnI and hs-cTnI, respectively. Compared with emergency physicians, cardiologists were less likely to classify cTnI orders as appropriate (cTnI: 79% vs 56%, P < .0001; hs-cTnI: 82% vs 51%, P < .0001). For contemporary cTnI, appropriateness of 95%, 70%, and 39% was observed among adjudication forms completed by cardiologists for type 1 myocardial infarction, type 2 myocardial infarction, and myocardial injury, respectively; compared with 90%, 86%, and 71%, respectively, among emergency physicians. Similar findings were observed using hs-cTnI. Discordance in appropriateness adjudication forms occurred most frequently in cases of myocardial injury (62% both assays) or type 2 myocardial infarction (cTnI 31%; hs-cTnI 23%).

CONCLUSIONS

Marked differences exist in the perception of what constitutes appropriate clinical use of cTn testing between cardiologists and emergency physicians, with emergency physicians more likely to see testing as appropriate across a range of clinical scenarios. Discordance derives most often from cases classified as myocardial injury or type 2 myocardial infarction.

Spinal manipulative therapy and exercise for older adults with chronic low back pain: a randomized clinical trial

Background

Low back pain (LBP) is a common disabling condition in older adults which often limits physical function and diminishes quality of life. Two clinical trials in older adults have shown spinal manipulative therapy (SMT) results in similar or small improvements relative to medical care; however, the effectiveness of adding SMT or rehabilitative exercise to home exercise is unclear.

Methods

We conducted a randomized clinical trial assessing the comparative effectiveness of adding SMT or supervised rehabilitative exercise to home exercise in adults 65 or older with sub-acute or chronic LBP. Treatments were provided over 12-weeks and self-report outcomes were collected at 4, 12, 26, and 52 weeks. The primary outcome was pain severity. Secondary outcomes included back disability, health status, medication use, satisfaction with care, and global improvement. Linear mixed models were used to analyze outcomes. The primary analysis included longitudinal outcomes in the short (week 4-12) and long-term (week 4-52). An omnibus test assessing differences across all groups over the year was used to control for multiplicity. Secondary analyses included outcomes at each time point and responder analyses. This study was funded by the US Department of Health and Human Services, Health Resources and Services Administration.

Results

241 participants were randomized and 230 (95%) provided complete primary outcome data. The primary analysis showed group differences in pain over the one-year were small and not statistically significant. Pain severity was reduced by 30 to 40% after treatment in all 3 groups with the largest difference (eight percentage points) favoring SMT and home exercise over home exercise alone. Group differences at other time points ranged from 0 to 6 percentage points with no consistent pattern favoring one treatment. One-year post-treatment pain reductions diminished in all three groups. Secondary self-report outcomes followed a similar pattern with no important group differences, except satisfaction with care, where the two combination groups were consistently superior to home exercise alone.

Conclusions

Adding spinal manipulation or supervised rehabilitative exercise to home exercise alone does not appear to improve pain or disability in the short- or long-term for older adults with chronic low back pain, but did enhance satisfaction with care.

Trial registration

NCT00269321.

Risk Estimation in Type 2 Myocardial Infarction and Myocardial Injury: The TARRACO Risk Score

BACKGROUND

Despite adverse prognoses of type 2 myocardial infarction and myocardial injury, an effective, practical risk stratification method remains an unmet clinical need. We sought to develop an efficient clinical bedside tool for estimating the risk of major adverse cardiovascular events at 180 days for this patient population.

METHODS

The derivation cohort included patients with type 2 myocardial infarction or myocardial injury admitted to a tertiary hospital between 2012 and 2013 (n = 611). The primary outcome was a major adverse cardiovascular event (death or readmission for heart failure or myocardial infarction). The score included clinical variables significantly associated with the outcome. External validation was conducted using the UTROPIA cohort (n = 401).

RESULTS

The TARRACO Score included cardiac troponin (cTn) concentrations and 5 independent clinical predictors of adverse cardiovascular events: age, hypertension, absence of chest pain, dyspnea, and anemia. The score exhibited good discriminative accuracy (area under the curve = 0.74; 95% CI, 0.70-0.79). Patients were classified into low-risk (score 0-6) and high-risk (score ≥7) categories. Major adverse cardiovascular events rates were 5 times more likely in high-risk patients compared with those at low risk (78.9 vs 15.4 events/100 patient-years, respectively; logrank P < .001). The external validation showed equivalent prognostic capacity (area under the curve=0.71, 0.65-0.78).

CONCLUSION

A novel risk score based on bedside clinical variables and cTn concentrations allows risk stratification for death and cardiac-related rehospitalizations in patients with type 2 myocardial infarctions and myocardial injury. This score identifies patients at the highest risk of adverse events, a subset of patients who may benefit from close observation, medical intensification, or both.

Kombinierter AHG- und PTA-Mangel

Es wird über die Kombination eines Faktor-VIII- und Faktor-XI-Mangels bei einem Patienten mit schwerer Blutungsneigung berichtet. Die Schwierigkeiten der Differentialdiagnose werden aufgezeigt und ähnliche Fälle in der Literatur diskutiert.

Use of objective evidence of myocardial ischemia to facilitate the diagnostic and prognostic distinction between type 2 myocardial infarction and myocardial injury

AIMS

First, describe how acute myocardial infarction criteria are used to diagnose type 1 (T1MI) and 2 (T2MI) myocardial infarction. Second, determine whether subjective or objective criteria are used for T2MI. Third, examine outcomes for T2MI based on the presence or absence of objective evidence of myocardial ischemia compared with myocardial injury.

METHODS AND RESULTS

Post-hoc analysis of UTROPIA (NCT02060760), a prospective, observational, cohort study involving 1640 consecutive emergency department patients with serial high-sensitivity cardiac troponin I among whom 74 (4.5%) had T1MI, 103 (6.3%) T2MI, and 245 (15%) myocardial injury. Compared with T1MI, patients with T2MI were less likely to have ischemic symptoms (97% vs. 83%), Q waves (24% vs. 1%), new ST-T wave changes (74% vs. 51%), new regional wall motion abnormality (64% vs. 11%), and a culprit lesion on coronary angiography (59% vs. 0%) (all p <0.05). T2MIs were more likely to be diagnosed using subjective criteria (symptoms alone) than T1MI (42% vs. 12%, p <0.0001). Patients with objective T2MI, but not subjective T2MI, had a two-fold increase in early mortality compared with myocardial injury, with 30- and 60-day hazard ratios (95% confidence interval) of 2.3 (0.9, 6.2) and 2.0 (0.9, 4.7) respectively.

CONCLUSIONS

Among patients with T2MI, many cases are diagnosed using subjective criteria. The presence of objective evidence of myocardial ischemia may identify a higher-risk group of T2MI patients in whom early outcomes are worse than myocardial injury. Emphasis on using objective evidence of myocardial ischemia to diagnose T2MI may result in a more precise and specific disease definition.

Renal Dysfunction Influences the Diagnostic and Prognostic Performance of High-Sensitivity Cardiac Troponin I

Measures of cardiac troponin (cTn) may have lower specificity for myocardial infarction in patients with CKD. We examined the diagnostic accuracy of baseline and serial high-sensitivity cTnI (hs-cTnI) measurements for myocardial infarction and 30- and 180-day mortality according to renal function. hs-cTnI was measured (Abbott assay) using sex-specific 99th percentiles (women, 16 ng/L; men, 34 ng/L) in 1555 adults presenting to the emergency department with symptoms suggesting ischemia (NCT02060760). Myocardial infarction was adjudicated along universal definition classification. Renal function did not significantly affect sensitivity or negative predictive values. Specificity decreased with impaired renal function from 93%-95% with normal function (eGFR≥90 ml/min per 1.73 m2; n=722) to 57%-61% with severely impaired renal function (eGFR<30 ml/min per 1.73 m2; n=81) and 40%-41% on dialysis (n=78). Positive predictive values decreased with decreasing renal function from 51%-57% with normal function to 27%-42% with severely impaired function and 15%-32% on dialysis. Receiver operating characteristic curve areas trended lower at baseline and 3 hours with renal impairment. Mortality increased significantly with increasing hs-cTnI tertile (1.3%, 6.0%, and 10.4%, respectively). Patients with hs-cTnI concentration exceeding concentrations in the 99th percentiles had a mortality rate (11.7%) significantly higher than that of patients with concentrations between 99th percentile concentrations and limit of detection (6.2%) or below limit of detection (1.1%). Renal dysfunction and dialysis reduced the rule-in performance but not the rule-out performance of hs-cTnI for myocardial infarction, and mortality increased in patients with higher hs-cTnI concentrations and any level of renal dysfunction.

Diagnostic Performance of High Sensitivity Compared with Contemporary Cardiac Troponin I for the Diagnosis of Acute Myocardial Infarction

BACKGROUND

We examined the diagnostic performance of high-sensitivity cardiac troponin I (hs-cTnI) vs contemporary cTnI with use of the 99th percentile alone and with a normal electrocardiogram (ECG) to rule out acute myocardial infarction (MI) and serial changes (deltas) to rule in MI.

METHODS

We included consecutive patients presenting to a US emergency department with serial cTnI onclinical indication. Diagnostic performance for acute MI, including MI subtypes, and 30-day outcomes were examined.

RESULTS

Among 1631 patients, MI was diagnosed in 12.9% using the contemporary cTnI assay and in 10.4% using the hs-cTnI assay. For ruling out MI, contemporary cTnI ≤99th percentile at 0, 3, and 6 h and a normal ECG had a negative predictive value (NPV) of 99.5% (95% CI, 98.6–100) and a sensitivity of 99.1% (95% CI, 97.4–100) for diagnostic and safety outcomes. Serial hs-cTnI measurements ≤99th percentile at 0 and 3 h and a normal ECG had an NPV and sensitivity of 100% (95% CI, 100–100) for diagnostic and safety outcomes. For ruling in MI, contemporary cTnI measurements had specificities of 84.4% (95% CI, 82.5–86.3) at presentation and 78.7% (95% CI, 75.4–82.0) with serial testing at 0, 3, and 6 h, improving to 89.2% (95% CI, 87.1–91.3) by using serial cTnI changes (delta, 0 and 6 h) &gt;150%. hs-cTnI had specificities of 86.9% (95% CI, 85.1–88.6) at presentation and 85.7% (95% CI, 83.5–87.9) with serial testing at 0 and 3 h, improving to 89.3% (95% CI, 87.3–91.2) using a delta hs-cTnI (0 and 3 h) &gt;5 ng/L.

CONCLUSIONS

hs-cTnI and contemporary cTnI assays are excellent in ruling out MI following recommendations predicated on serial testing and the 99th percentile with a normal ECG. For ruling in MI, deltas improve the specificity. ClinicalTrials.gov Identifier: NCT02060760

Single High-Sensitivity Cardiac Troponin I to Rule Out Acute Myocardial Infarction

BACKGROUND

This study examined the performance of single high-sensitivity cardiac troponin I (hs-cTnI) measurement strategies to rule out acute myocardial infarction.

METHODS

This was a prospective, observational study of consecutive patients presenting to the emergency department (n = 1631) in whom cTnI measurements were obtained using an investigational hs-cTnI assay. The goals of the study were to determine 1) negative predictive value (NPV) and sensitivity for the diagnosis of acute myocardial infarction, type 1 myocardial infarction, and type 2 myocardial infarction; and 2) safety outcome of acute myocardial infarction or cardiac death at 30 days using hs-cTnI less than the limit of detection (LoD) (<1.9 ng/L) or the High-STEACS threshold (<5 ng/L) alone and in combination with normal electrocardiogram (ECG).

RESULTS

Acute myocardial infarction occurred in 170 patients (10.4%), including 68 (4.2%) type 1 myocardial infarction and 102 (6.3%) type 2 myocardial infarction. For hs-cTnI<LoD (27%), the NPV and sensitivity for acute myocardial infarction were 99.6% (95% confidence interval 98.9%-100%) and 98.8 (97.2%-100%). For hs-cTnI<5 ng/L (50%), the NPV and sensitivity for acute myocardial infarction were 98.9% (98.2%-99.6%) and 94.7% (91.3%-98.1%). In combination with a normal ECG, 1) hs-cTnI<LoD had an NPV of 99.6% (98.9%-100%) and sensitivity of 99.4% (98.3%-100%); and 2) hs-cTnI<5 ng/L had an NPV of 99.5% (98.8%-100%) and sensitivity of 98.8% (97.2%-100%). The NPV and sensitivity for the safety outcome were excellent for hs-cTnI<LoD alone or in combination with a normal ECG, and for hs-cTnI<5 ng/L in combination with a normal ECG.

CONCLUSION

Strategies using a single hs-cTnI alone or in combination with a normal ECG allow the immediate identification of patients unlikely to have acute myocardial infarction and who are at very low risk for adverse events at 30 days.

Use of Electronic Versus Print Textbooks by Chilean Dental Students: A National Survey

Electronic textbooks have become available in recent decades as replacements or alternatives for print versions. The aim of this descriptive cross-sectional study was to evaluate the use of electronic versus print textbooks by Chilean dental students. The target population was students from 14 Chilean dental schools. The questionnaire was adapted and translated to Spanish from a previous survey used in a similar study. It consisted of the following variables: preferred type, type used, frequency of use, source, electronic devices used to read, and disposal after use. The use of textbooks was analyzed and compared by gender and course (p≤0.05). The final sample consisted of 3,256 students (21.38±2.5 years of age, 50.8% women). Most of the participants reported using both types of texts, with most (63.9%) preferring print over electronic texts, including significantly more women (p<0.001) and first-year students (p<0.001). Most of the participants (82.8%), more women (p<0.001), and with variations over years of study (p<0.001) reported that they printed out their electronic texts, and 91.8% kept their printed material. Most of the students used electronic books on a daily basis (47.3%) or at least twice a week (30.7%). The main source of electronic textbooks was the Internet (43.8%). A personal computer was the most widely used device for reading electronic texts (95.0%), followed by a cell phone (46.4%) and a tablet (24.5%). Overall, these Chilean dental students preferred print over electronic textbooks, despite having available electronic devices.

Rapid Rule-Out of Acute Myocardial Injury Using a Single High-Sensitivity Cardiac Troponin I Measurement

BACKGROUND

Rapid rule-out strategies using high-sensitivity cardiac troponin assays are largely supported by studies performed outside the US in selected cohorts of patients with chest pain that are atypical of US practice, and focused exclusively on ruling out acute myocardial infarction (AMI), rather than acute myocardial injury, which is more common and associated with a poor prognosis.

METHODS

Prospective, observational study of consecutive patients presenting to emergency departments [derivation (n = 1647) and validation (n = 2198) cohorts], where high-sensitivity cardiac troponin I (hs-cTnI) was measured on clinical indication. The negative predictive value (NPV) and diagnostic sensitivity of an hs-cTnI concentration

RESULTS

In patients with hs-cTnI concentrations <99th percentile at presentation, acute myocardial injury occurred in 8.3% and 11.0% in the derivation and validation cohorts, respectively. In the derivation cohort, 27% had hs-cTnI < LoD, with NPV and diagnostic sensitivity for acute myocardial injury of 99.1% (95% CI, 97.7-99.8) and 99.0% (97.5-99.7) and an NPV for AMI or cardiac death at 30 days of 99.6% (98.4-100). In the validation cohort, 22% had hs-cTnI

CONCLUSIONS

A single hs-cTnI concentration Collapse

Key Words Collapse

MESH Headings

• Acute Disease
• Cohort Studies
• Female
• Humans
• Male
• Middle Aged
• Myocardial Ischemia/blood
• Myocardial Ischemia/diagnosis
• Troponin I/blood

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Grants

• FS/16/75/32533 British Heart Foundation
• SP/12/10/29922 British Heart Foundation
• HICG/1/40 Chief Scientist Office
• FS/16/14/32023 British Heart Foundation
• PG/15/51/31596 British Heart Foundation
• FS/10/024/28266 British Heart Foundation

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Affiliation(s)

Yader Sandoval Division of Cardiology, Hennepin County Medical Center, Minneapolis, MN Minneapolis Heart Institute, Abbott-Northwestern Hospital, Minneapolis, MN Minneapolis Medical Research Foundation, Minneapolis, MN
Stephen W Smith Minneapolis Medical Research Foundation, Minneapolis, MN Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, MN
Anoop S V Shah BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
Atul Anand BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
Andrew R Chapman BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
Sara A Love Minneapolis Medical Research Foundation, Minneapolis, MN Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN
Karen Schulz Minneapolis Medical Research Foundation, Minneapolis, MN
Jing Cao Minneapolis Medical Research Foundation, Minneapolis, MN
Nicholas L Mills BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
Fred S Apple Minneapolis Medical Research Foundation, Minneapolis, MN; Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN

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Discordance between ICD-Coded Myocardial Infarction and Diagnosis according to the Universal Definition of Myocardial Infarction

BACKGROUND

International Classification of Diseases (ICD) coding is the standard diagnostic tool for healthcare management. At present, type 2 myocardial infarction (T2MI) classification by the Universal Definition of Myocardial Infarction (MI) remains ignored in the ICD system. We determined the concordance for the diagnosis of MI using ICD-9 coding vs the Universal Definition.

METHODS

Cardiac troponin I (cTnI) was measured by both contemporary (cTnI) and high-sensitivity (hs-cTnI) assays in 1927 consecutive emergency department (ED) patients [Use of TROPonin In Acute coronary syndromes (UTROPIA) cohort] who had cTnI ordered on clinical indication. All patients were adjudicated using both contemporary and hs-cTnI assays. The Kappa index and McNemar test were used to assess concordance between ICD-9 code 410 and type 1 MI (T1MI) and type 2 MI (T2MI).

RESULTS

Among the 249 adjudicated MIs using the contemporary cTnI, only 69 (28%) were ICD-coded MIs. Of 180 patients not ICD coded as MI, 34 (19%) were T1MI and 146 (81%) were T2MI. For the ICD-coded MIs, 79% were T1MI and 21% were T2MI. A fair Kappa index, 0.386, and a McNemar difference of 0.0892 (P &lt; 0.001) were found. Among the 207 adjudicated MIs using the hs-cTnI assay, 67 (32%) were ICD coded as MI. Of the 140 patients not ICD coded as MI, 27 (19%) were T1MI and 113 (81%) were T2MI. For the ICD-coded MIs, 85% were T1MI and 15% T2MI. A moderate Kappa index, 0.439, and a McNemar difference of 0.0674 (P &lt; 0.001) were found.

CONCLUSIONS

ICD-9–coded MIs captured only a small proportion of adjudicated MIs, primarily from not coding T2MI. Our findings emphasize the need for an ICD code for T2MI.

A Simulation Model to Determine Sensitivity and Timeliness of Surveillance Strategies

Animal surveillance systems need regular evaluation. We developed an easily applicable simulation model of the German wild boar population to investigate two evaluation attributes: the sensitivity and timeliness (i.e. the ability to detect a disease outbreak rapidly) of a surveillance system. Classical swine fever (CSF) was used as an example for the model. CSF is an infectious disease that may lead to massive economic losses. It can affect wild boar as well as domestic pigs, and CSF outbreaks in domestic pigs have been linked to infections in wild boar. Awareness of the CSF status in wild boar is therefore vital. Our non-epidemic simulation model is based on real data and evaluates the currently implemented German surveillance system for CSF in wild boar. The results show that active surveillance for CSF fulfils the requirements of detecting an outbreak with 95% confidence within one year after the introduction of CSF into the wild boar population. Nevertheless, there is room for improved performance and efficiency by more homogeneous (active and passive) sampling of wild boar over the year. Passive surveillance alone is not sufficient to meet the requirements for detecting the infection. Although CSF was used as example to develop the model, it may also be applied to the evaluation of other surveillance systems for viral diseases in wild boar. It is also possible to compare sensitivity and timeliness across hypothetical alternative or risk-based surveillance strategies.

Incidence of Undetectable, Measurable, and Increased Cardiac Troponin I Concentrations Above the 99th Percentile Using a High-Sensitivity vs a Contemporary Assay in Patients Presenting to the Emergency Department

INTRODUCTION

We compared the incidence of undetectable [below the limit of detection (LoD)], measurable (LoD to 99th percentile), and increased cardiac troponin I (cTnI) concentrations above the 99th percentile between Abbott high-sensitivity cTnI (hs-cTnI) and contemporary cTnI assays in a US emergency department population.

METHODS

Patients (n = 2100) presenting to the emergency department who had serial cTnI (0, 3, 6, 9 h) measurements ordered on clinical indication were enrolled. Contemporary cTnI [Abbott Architect used clinically; 99th percentile: 0.030 μg/L (30 ng/L)] and hs-cTnI [Abbott investigational; sex-specific 99th percentiles: female (F) 16 ng/L, male (M) 34 ng/L] assays simultaneously measured fresh EDTA plasma.

RESULTS

The hs-cTnI assay measured fewer undetectable cTnI concentrations compared to the contemporary cTnI assay across baseline (F: 31% vs 47%, M: 22% vs 40%) and serial (F: 21% vs 46%; M: 19% vs 54%) measurements. Conversely, the proportion of measurable cTnI concentrations was higher using hs-cTnI compared to contemporary cTnI assay across both baseline (F: 46% vs 31%; M: 60% vs 33%) and serial (F: 48% vs 28%; M: 83% vs 40%) measurements. The overall proportion of patients with increased cTnI concentrations above the 99th percentile was not significantly different between the contemporary (31%) and hs-cTnI (26%) assays (P = 0.09).

CONCLUSIONS

In patients presenting to the emergency department, the use of the Abbott hs-cTnI assay provides clinicians with more numeric cTnI concentrations. This occurs via a shift from results below the LoD to those between the LoD and the 99th percentile and does not increase in the number of cTnI concentrations above the 99th percentile.