Emergency Department Chest Pain Patients Research Articles

A Single High-Sensitivity Cardiac Troponin T Strategy for Ruling Out Myocardial Infarction.

Ruling out acute myocardial infarction (AMI) in the emergency department (ED) is challenging. Studies have shown that a high-sensitivity cardiac troponin T (hs-cTnT) <5 ng/L or <6 ng/L at presentation (0 h) can be used to rule out AMI. The objective of this study was to identify whether an even higher hs-cTnT threshold can be used for a safe rule out of AMI in the ED. The derivation cohort consisted of 24,973 ED patients with a primary complaint of chest pain. In this cohort, we identified the highest concentration of 0 h hs-cTnT that corresponded to a negative predictive value (NPV) of ≥99.5% for the primary endpoint of AMI/all-cause death within 30 days and the secondary endpoint of all-cause death within one year. The results were validated in two cohorts consisting of 132,021 and 1167 ED chest pain patients. The 0 h hs-cTnT threshold corresponding to a NPV of ≥99.5% for the primary endpoint was <9 ng/L (NPV: 99.6% and 95% CI: 99.5-99.7). This cutoff provided a sensitivity of 96.2% (95% CI: 95.2-97.1) and identified 59.7% of the patients as low risk compared to 35.8% and 43.9% with a 0 h hs-cTnT <5 ng/L and <6 ng/L, respectively. The results were similar in the validation cohorts and seemed to perform even better in patients where the 0 h hs-cTnT was measured >3 h after symptom onset and in those with a nonischemic ECG and nonhigh risk history. A 0 h hs-cTnT cutoff of <9 ng/L safely rules out AMI/death within 30 days in a majority of chest pain patients and is a more effective strategy than the currently recommended <5 ng/L and <6 ng/L cutoffs. This trial is registered with NCT03421873.

Prior electrocardiograms not useful for machine learning predictions of major adverse cardiac events in emergency department chest pain patients

At the emergency department (ED), it is important to quickly and accurately determine which patients are likely to have a major adverse cardiac event (MACE). Machine learning (ML) models can be used to aid physicians in detecting MACE, and improving the performance of such models is an active area of research. In this study, we sought to determine if ML models can be improved by including a prior electrocardiogram (ECG) from each patient. To that end, we trained several models to predict MACE within 30 days, both with and without prior ECGs, using data collected from 19,499 consecutive patients with chest pain, from five EDs in southern Sweden, between the years 2017 and 2018. Our results indicate no improvement in AUC from prior ECGs. This was consistent across models, both with and without additional clinical input variables, for different patient subgroups, and for different subsets of the outcome. While contradicting current best practices for manual ECG analysis, the results are positive in the sense that ML models with fewer inputs are more easily and widely applicable in practice.

Derivation of a HEAR Pathway for Emergency Department Chest Pain Patients to Safely Avoid a Second Troponin Test.

The study aims to develop a decision pathway based on HEAR score and 0 h high-sensitivity cardiac troponin T (hs-cTnT) to safely avoid a second troponin test for suspected non-ST elevation myocardial infarction (NSTEMI) in emergency departments. A HEAR score consists of history, electrocardiogram, age, and risk factors. A HEAR pathway is established using a Bayesian approach based on a predefined safety threshold of NSTEMI prevalence in the rule-out group. In total, 7131 patients were retrospectively enrolled, 582 (8.2%) with index visit NSTEMI and 940 (13.2%) with 180-day major adverse cardiovascular events (MACE). For patients with a low-risk HEAR score (0 to 2) and low 0 h hs-cTnT (<14 ng/L), the HEAR pathway recommends early discharge without further testing. After the HEAR pathway had been applied to rule out NSTEMI, the negative predictive value of index visit NSTEMI was 100.0% (95% CI, 99.8% to 100.0%) and false-negative rate of 180-day MACE was 0.40% (95% CI, 0.18% to 0.87%). Compared with the 0 h hs-cTnT < limit of detection (LoD) strategy (<5 ng/L), the HEAR pathway could correctly reclassify 1298 patients without MACE as low risk and lead to a 18.2% decrease (95% CI, 17.4-19.1%) in the need for a second troponin test. The HEAR pathway may lead to a substantial and safe reduction in repeated troponin test for emergency department patients with suspected NSTEMI.

Impact of HEART Score Decision Aid on Coronary Computed Tomography Angiography Utilization and Diagnostic Yield in the Emergency Department.

Emergency physicians are challenged to efficiently and reliably risk stratify patients presenting with chest pain (CP) to optimize diagnostic testing and avoid unnecessary hospital admissions. The objective of our study was to evaluate the impact of a HEART score-based decision aid (HSDA) integrated in the electronic health record on coronary computed tomography angiography (CCTA) utilization and diagnostic yield in adult emergency department (ED) CP patients with suspected acute coronary syndrome. We conducted a before and after study to determine whether implementation of a mandatory computerized HSDA would reduce CCTA utilization in ED CP patients and improve the diagnostic yield of obstructive coronary artery disease (CAD) (≥50%). We included all adult ED CP patients with suspected acute coronary syndrome during the first 6 months of 2018 (before) and 2020 (after) at a large academic center. CCTA utilization and obstructive CAD yield were compared in patients before and after implementing the HSDA using χ2 tests. Secondarily, we assessed the association of HEART scores and CCTA results. Of the 3095 CP patients during the before study period, 733 underwent CCTA. Of the 2692 CP patients during the after study period, 339 underwent CCTA. CCTA utilization before and after HSDA was 23.4% [95% confidence interval (95% CI), 22.2-25.2] and 12.6% (95% CI, 11.4-13.0), respectively; mean difference was 11.1% (95% CI, 0.9-13.0). Among 1072 patients undergoing CCTA, mean (SD) age and percent females before versus after HSDA were 54 (11) versus 56 (11) years and 50% versus 49%, respectively. We included 1014 patients (686 before and 328 after) for the yield analysis. Obstructive CAD was present in 15% (95% CI, 12.7-17.9) and 20.1% (95% CI, 16.1-24.7) before and after HSDA, respectively; mean difference was 4.9% (95% CI, 0.1-10.1). Implementation of a mandatory electronic health record HSDA aid reduced ED CCTA utilization by half and improved the diagnostic yield.

Machine learning for early prediction of acute myocardial infarction or death in acute chest pain patients using electrocardiogram and blood tests at presentation

AimsIn the present study, we aimed to evaluate the performance of machine learning (ML) models for identification of acute myocardial infarction (AMI) or death within 30 days among emergency department (ED) chest pain patients.Methods and resultsUsing data from 9519 consecutive ED chest pain patients, we created ML models based on logistic regression or artificial neural networks. Model inputs included sex, age, ECG and the first blood tests at patient presentation: High sensitivity TnT (hs-cTnT), glucose, creatinine, and hemoglobin. For a safe rule-out, the models were adapted to achieve a sensitivity > 99% and a negative predictive value (NPV) > 99.5% for 30-day AMI/death. For rule-in, we set the models to achieve a specificity > 90% and a positive predictive value (PPV) of > 70%. The models were also compared with the 0 h arm of the European Society of Cardiology algorithm (ESC 0 h); An initial hs-cTnT < 5 ng/L for rule-out and ≥ 52 ng/L for rule-in. A convolutional neural network was the best model and identified 55% of the patients for rule-out and 5.3% for rule-in, while maintaining the required sensitivity, specificity, NPV and PPV levels. ESC 0 h failed to reach these performance levels.DiscussionAn ML model based on age, sex, ECG and blood tests at ED arrival can identify six out of ten chest pain patients for safe early rule-out or rule-in with no need for serial blood tests. Future studies should attempt to improve these ML models further, e.g. by including additional input data.

Socioeconomic status and waiting time in the emergency department for patients with chest pain

Abstract Introduction Acute coronary syndrome (ACS) is one of the leading causes of death in the world and timeliness of treatment and diagnosis is of utmost importance to reduce mortality and morbidity. Emergency department (ED) crowding results in longer waiting times and length of stay in the ED and is a globally growing phenomenon with clear negative consequences for patients. Low socioeconomic status (SES) has previously been associated with poor prognosis after ACS, but it remains unclear if treatment and diagnostics in the acute state is a contributing factor. ED length of stay has been linked to crowding and poor patient outcomes whereas mechanisms for generally worse prognosis in low SES remains poorly understood. Purpose To investigate whether SES, measured as disposable income, is associated with ED waiting times among patients with the most common chief complaint in ACS, chest pain. Methods A registry-based cohort study on all 140,388 patients arriving at 14 Swedish emergency departments between 2015 and 2019 with chest pain as their chief complaint registered in the Swedish Emergency Registry (SVAR). Individual-level sociodemographic and clinical data were linked from multiple national registries. The associations between disposable income quintiles and ED length of stay and time to doctor were assessed using multivariable regression models adjusting for age, sex, education, comorbidities (diabetes, hypertension, hyperlipidemia, obesity and cardiovascular disease) and ED-visit characteristics (arrival mode, triage level, arrival time (day, evening or night as well as weekday or weekend) and hospital type). Results Median length of stay was 11 minutes (4.4%) longer among patients in the lowest income quintile, 4:04 [hours:minutes] (95% confidence interval [CI] 4:02–4:05), compared to patients in the highest income quintile (3:53, 95% CI 3:52–3:55). Similarly, time to doctor was 6 min (8.7%) longer among patients in the lowest income quintile (1:15 min, 95% CI 1:14–1:16) than patients in the highest income quintile (1:09, 95% CI 1:08–1:10). The associations were independent of adjustment for studied confounders and mediators. Conclusions Among ED chest pain patients, low income was associated with longer length of stay and time to doctor which may impact negatively on patients with serious cardiovascular diagnosis such as ACS. Longer waiting times may delay diagnosis and timely treatment for the individual patient such as anti-ischemic and antithrombotic therapy. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by grants provided by Region Stockholm (ALF-project)

Patient satisfaction with an advanced nurse practitioner (ANP) integrated community chest pain clinic

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): Martha McMenamin Scholarship, small grant awarded Background Patient presentations with chest pain to the Emergency Department (ED) account for 9% of ED attendances. In the primary care setting chest pain is a common presenting complaint with an over diagnosis/suspicion of stable angina, however General Practitioners (GPs) lack access to a cardiac specialist in a timely fashion. As a result 31% of all ED chest pain patients are referred by GPs. The innovative integrated community chest pain clinic (ICCPC) commenced in September 2020. This Advanced Nurse Practitioner (ANP) led clinic aims to provide an alternative avenue to which GPs can directly refer patients with non-acute chest pain, thereby shifting the focus of care from the acute hospital environment Purpose Integrated community based care and ANP led care are new phenomena to the Irish patient. This paper explores patient satisfaction with the ANP led integrated community chest pain clinic Method This quantitative descriptive study invited participation from ICCPC patients over a six-month period (N=177). The questionnaire was adapted from Cross et al, (2010). Return of the anonymous questionnaire was by freepost/Qualtrics. Ratings were based on a five-point scale from ‘Poor’ to ‘Excellent’. Satisfaction and experience of ANP led community care was evaluated and satisfaction with appointment scheduling, waiting times, service provision and follow-up care was measured. Quantitative data were analysed using descriptive statistics. A combination of ‘good’ very good’ and ‘excellent’ are taken to mean a positive rating. Ethical approval was granted by the hospital ethics committee. Results A response rate of 43.5% (n=77) was achieved, including female (55.2%) white Irish (85.1%) and age range 50–69 yrs (53%). Confidence in the level of assessment by the ANP received a 100% (n=77) positive rating. All responders felt safe in the clinic 100% (n=74). Appointment waiting times received positive ratings: GP to ICCPC waiting times 98% (74/75); referral from ICCPC to hospital for stress test 92% (35/38); and 94.3% (50/53) positive rating regarding waiting times for phone-reported test results. Suggestions for improvements included the need for clearer signage/easier access to the ICCPC and a preference for follow-up check-ups by the ICCPC. If discharged for hospital follow up some wished for clearer follow-on care plans from the hospital. Conclusion and Implications This study suggests that the ANP led integrated community chest pain clinic plays a crucial role in meeting the needs of integrated patient centred care. The ANP led clinic was well received by patients and is a blueprint for other community initiatives. Many positive comments were included, with one participant stating "this service should be in every community, I think this would encourage people to go to the GP about mild chest pain without the fear of being sent to ED".

Using HEART2 score to risk stratify chest pain patients in the Emergency Department: an observational study

BackgroundA significant number of chest pain patients had previous cardiac imaging tests (CIT) performed before being presented to the Emergency Department (ED). The HEART (history, electrocardiogram, age, risk factors, and troponin) score has been used to risk-stratify chest pain patients in the ED, but not particularly for patients with CIT performed. We aim to modify the current HEART score with the addition of most recent CIT findings (referred to as HEART2 score), to predict a 30-day major adverse cardiac event (MACE) among ED chest pain patients, compare the performance accuracy of using HEART versus HEART2 score for 30-day MACE outcome predictions, and further determine the value of HEART2 in a subset group of ED chest pain patients (i.e., ones with previous CIT).MethodsThis is a single-center observational study. We included chest pain patients with HEART scores calculated during their index ED visits. A modified HEART2 score was developed with the addition of CIT findings as one of the HEART2 components. Patients were divided into three groups, including low (≤ 3), moderate (4–6), and high-risk HEART/HEART2 scores (≥ 7). MACE occurrence of a patient with different risks of HEART and HEART2 scores and overall performance accuracy of HEART versus HEART2 score predicting MACE outcomes were compared.ResultsWe included a total of 9419 chest pain patients at ED, among which one out of five patients (1874/9419) had previous CIT performed. Fewer (38.2%) of such patients had low-risk HEART scores in comparison to 55.5% of low-risk HEART2 scores (p < 0.001). The MACE outcomes were similar in low-risk HEART patients compared with low-risk HEART2 patients (2.2% versus 3.1%, p = 0.3021). The overall performance accuracy of using the HEART2 score to stratify chest pain patients with previous CIT was better than using the HEART score’s (AUC 0.74 versus 0.71, p = 0.0082).ConclusionsUsing the HEART2 score might be suitable to stratify low-to-moderate risk chest pain patients at ED with a similar 30-days MACE occurrence compared to the HEART score. More importantly, with the use of similar low-risk criteria (HEART2 ≤ 3), over 45% more chest pain patients with previous CIT performed could be discharged directly from ED.

Adding historical high-sensitivity troponin T results to rule out acute myocardial infarction.

The clinical usefulness of historical concentrations of high-sensitivity cardiac troponin T (hs-cTnT) is unknown. This study investigated the ability to rule out myocardial infarction (MI) with the use of historical hs-cTnT concentrations among patients with chest pain in the emergency department (ED). The derivation cohort consisted of patients presenting with chest pain to nine different EDs (n = 60 071), where we included those with ≥1 hs-cTnT analysed at the index visit and ≥1 hs-cTnT results prior to the visit. We developed an algorithm to rule out MI within 30 days with a pre-specified target negative predictive value (NPV) of ≥99.5%. The performance was then validated in a separate cohort of ED chest pain patients (n = 10 994). A historical hs-cTnT < 12 ng/L and a < 3 ng/L absolute change between the historical and the index visit hs-cTnT had the best performance and ruled out 24 862 (41%) patients in the derivation cohort. In the validation cohort, these criteria identified 4764 (43%) low-risk patients in whom 18 (0.4%) MIs within 30 days occurred, and had an NPV for MI of 99.6% (99.4-99.8), a sensitivity of 96.9% (95.2-.2), and an LR- of 0.11 (0.07-0.14). Combining a historical hs-cTnT with a single new hs-cTnT may safely rule out MI and thereby reduce the need for serial hs-cTnT measurements in ED patients with chest pain.

Accuracy of emergency department chest pain patients' reporting of coronary disease history

Introduction:History is an important component of emergency department risk stratification for chest pain patients. We hypothesized that a significant portion of patients would not be able to accurately report their history of coronary artery disease (CAD) and diagnostic testing.Methods:We prospectively enrolled a convenience sample of a cohort of adult ED patients with a chief complaint of chest pain. They completed a structured survey that included questions regarding prior testing for CAD and cardiac history. Study authors performed a structured chart review within the electronic medical record for our 6-hospital system. Results of testing for CAD, cardiac interventions, and chart diagnoses of CAD/acute myocardial infarction (AMI) were recorded. Categorical data were analyzed by Chi-square and continuous data by logistic regression.Results:About 196 patients were enrolled; mean age 57 ± 15 years, 48% female, 67% Hispanic, 50% income <$20,000/year. About 43% (95% confidence interval [CI] 35%–51%) of patients stated that they did not have CAD, yet medical records indicated that they were CAD+. With increasing age, patients were more likely to accurately report the absence of CAD (P < 0.001). There was no association between patients reporting no CAD, but CAD+ in records with respect to the following characteristics: female gender (P = 0.37), Hispanic race (P = 0.73), income (P = 0.41), less than or equal to high school education (P = 0.11), and private insurance (P = 0.71). For patients with prior AMI, 7.2% (95% CI 2.7%–11%) reported no prior history of AMI.Conclusions:Within our study group from a predominantly poor, Hispanic population, patients had a poor recall for the presence of CAD in their medical history.

Glucose and high-sensitivity troponin T predict a low risk of major adverse cardiac events in emergency department chest pain patients

Background. Glucose is emerging as a biomarker for early and safe rule-out of acute myocardial infarction in emergency department (ED) chest pain patients. We evaluated the diagnostic accuracy of dual testing with high sensitivity TnT (hs-cTnT) and glucose for prediction of major adverse cardiac events (MACE) within 30 days. Methods. This was a secondary analysis of a single-center prospective observational study of 1167 ED chest-pain patients with hs-cTnT and glucose testing at presentation (0 h), and hs-cTnT 1 h later. We tested the addition of glucose <5.6 mmol/L to three MACE rule-out strategies: hs-cTnT <5 ng/L, ≤14 ng/L or a 0 h/1h algorithm, i.e. initial hs-cTnT <12 ng/L with a 1 h change of <3 ng/L. We also tested the addition of glucose ≥11mmol/L to three rule-in strategies: hs-cTnT ≥52 ng/L, a 1 h change ≥5 ng/L or hs-cTnT >14 ng/L. The outcomes were 30-day MACE and 30-day MACE without UA. Results. Two dual-testing approaches reached our target NPV for rule-out: A 0 h hs-cTnT ≤14 ng/L and glucose <5.6 mmol/L identified 252 patients (24.4%) with a 98.8% NPV for 30-day MACE and 99.6% for MACE without UA. The 0 h/1h hs-cTnT algorithm combined with glucose identified 240 patients (23.2%) with a 99.2% NPV for 30-day MACE and 100.0% for MACE without UA. No dual rule-in strategy performed better than using hs-cTnT alone. Conclusions. A combination of hs-cTnT and blood glucose at presentation can be used to identify almost ¼ of ED chest pain patients with a very low risk of 30-day MACE where further testing is not needed. Adding glucose did not improve the rule-in of 30-day MACE.

102 Detection of Acute Coronary Syndrome by Magnetocardiography

To evaluate the use of magnetocardiography (MCG) for early identification or rule out of acute coronary syndromes (ACS) in emergency department (ED) patients with chest pain. Magnetocardiography is a noninvasive imaging method that measures the electromagnetic fields generated by the heart’s activity. MCG is rapid, easy to perform, and provides a radiation-free imaging assessment for patients with suspected ACS. This is a prospective, observational, multicenter trial comparing the accuracy and time to disposition of ED standard of care (SOC) vs. MCG. Patients were enrolled at 3 sites from January to May 2021. Inclusion criteria were ED patients with chest pain, age ≥ 18 years, modified heart score > 2, and signs/symptoms of ACS in the ED. Exclusion criteria were STEMI, unable to fit into the device, non-ambulatory, hemodynamically unstable, and unable to lie supine for up to 5 minutes. Additional exclusion criteria were patients with pacemakers, AICD, other active devices, or any ferromagnetic metal above the costal margins. Patients underwent a MCG scan in addition to ED SOC. MCG was performed within 4 hours of ED triage. We hypothesize that the use of MCG will lead to shorter ED length of stay (LOS), with equal or improved diagnosis of suspected ACS patients. Of 58 scans, 32 were available for evaluation. 26 were unevaluable due to either insufficient data or uninterpretable. Patients with any artifacts were considered unevaluable. With technical improvements, the arttifact on current scans may be decreased which will result in fewer unevaluable scans. Mean age was 51.3 (SD± 1 .9) years, 50% female, 59.4% Black, 37.5% White, 3.1% other. Mean HEART score was 4.2 (SD± 1.1). Mean number of cardiovascular risk factors was 3.0 (SD± 1.6). Mean LOS (minutes) for MCG was 187 (SD ± 122) vs. SOC 812 (SD ± 73) (P < 0.0001 by paired t-test) (95% CI difference: -882.0, - 368.1). Thus, when compared with standard of care evaluation alone, the mean length-of-stay could have been reduced by 10.6 hours without any significant change in diagnostic accuracy. MCG and SOC based on troponins were both negative in 28 patients.There were 2 false positives by SOC (6.2%, 2/32). In these two patients presumed to have ACS by SOC, both went to cardiac catheterization, which revealed no ACS. MCG correctly identified the patients to have no ACS. There were two false negatives by MCG. In these two patients, MCG was positive and SOC rule out by troponins was negative. No stress test or cardiac catheterization was done in these two patients. Eleven patients (34%) were placed in the observation unit (OU). The MCG done in the ED and the rule out in the OU were both negative for ACS. Furthermore, early MCG done in the ED as compared with standard of care evaluation alone, would potentially eliminate overnight observation unit stays in 34% of the study population. Magnetocardiography results in a significantly lower LOS for chest pain in the ED which could lead to decreased ED LOS, improved ED turnaround times and better ED efficiency. MCG may avoid an OU stay with resultant cost savings in about one-third of ED chest pain patients. More importantly, MCG detected patients who were false positive by SOC and could have avoided a cardiac catheterization. MCG had two false positives which were negative by troponins but no cardiac catheterization or stress test were done in these two patients.

External validation of a low HEAR score to identify emergency department chest pain patients at very low risk of major adverse cardiac events without troponin testing.

The history, ECG, age, risk factor (HEAR) score has been proposed to identify patients at sufficiently low risk of acute coronary syndrome that they may not require troponin testing. The objective of this study was to externally validate a low HEAR score to identify emergency department (ED) patients with chest pain at very low risk of 30-day major adverse cardiac events (MACE). This was a secondary analysis of a prospective cohort of patients requiring troponin testing to rule out myocardial infarction (MI) in a large urban ED. HEAR scores were calculated in two cohorts: (1) patients with no known history of coronary arterydisease (CAD); and (2) all eligible patients. The proportion of patients classified as very low risk, sensitivity, specificity, predictive values and likelihood ratios at each cut-off were quantified for index acute myocardial infarction (AMI) and 30-day MACE at HEAR = 0 and HEAR ≤ 1 thresholds. Of the 1150 patients included in this study, 820 (71.3%) had no history of CAD, 97 (8.4%) had index AMI and 123 (10.7%) had 30-day MACE. In patients with no prior history of CAD, HEAR ≤ 1 identified 202 (24.6%) of patients as very low risk for 30-day MACE with 98.4% (95% CI 91.6-99.9%) sensitivity. Among all patients, HEAR ≤ 1 identified 202 (17.6%) patients as very low risk for 30-day MACE with 99.2% (95% CI 95.6-99.9%) sensitivity. A HEAR score ≤ 1 can identify more than 17% of all patients as very low risk for index AMI and 30-day MACE and unlikely to benefit from troponin testing. Broad implementation of this strategy could lead to significant resource savings.

A Prospective Evaluation of Clinical HEART Score Agreement, Accuracy, and Adherence in Emergency Department Chest Pain Patients

The HEART score is a risk stratification aid that may safely reduce chest pain admissions for emergency department patients. However, differences in interpretation of subjective components potentially alters the performance of the score. We compared agreement between HEART scores determined during clinical practice with research-generated scores and estimated their accuracy in predicting 30-day major adverse cardiac events. We prospectively enrolled adult ED patients with symptoms concerning for acute coronary syndrome at a single tertiary center. ED clinicians submitted their clinical HEART scores during the patient encounter. Researchers then independently interviewed patients to generate a research HEART score. Patients were followed by phone and chart review for major adverse cardiac events. Weighted kappa; unweighted Cohen's kappa; prevalence-adjusted, bias-adjusted kappa (PABAK); and test probabilities were calculated. From November 2016 to June 2019, 336 patients were enrolled, 261 (77.7%) were admitted, and 30 (8.9%) had major adverse cardiac events. Dichotomized HEART score agreement was 78% (kappa 0.48, 95% confidence interval [CI] 0.37 to 0.58; PABAK 0.57, 95% CI 0.48 to 0.65) with the lowest agreement in the history (72%; WK 0.14, 95% CI 0.06 to 0.22) and electrocardiogram (85%; WK 0.4, 95% CI 0.3 to 0.49) components. Compared with researchers, clinicians had 100% sensitivity (95% CI 88.4% to 100%) (versus 86.7%, 95% CI 69.3% to 96.2%) and 27.8% specificity (95% CI 22.8% to 33.2%) (versus 34.6%, 95% CI 29.3% to 40.3%) for major adverse cardiac events. Four participants with low research HEART scores had major adverse cardiac events. ED clinicians had only moderate agreement with research HEART scores. Combined with uncertainties regarding accuracy in predicting major adverse cardiac events, we urge caution in the widespread use of the HEART score as the sole determinant of ED disposition.

Utilizing machine learning dimensionality reduction for risk stratification of chest pain patients in the emergency department

BackgroundChest pain is among the most common presenting complaints in the emergency department (ED). Swift and accurate risk stratification of chest pain patients in the ED may improve patient outcomes and reduce unnecessary costs. Traditional logistic regression with stepwise variable selection has been used to build risk prediction models for ED chest pain patients. In this study, we aimed to investigate if machine learning dimensionality reduction methods can improve performance in deriving risk stratification models.MethodsA retrospective analysis was conducted on the data of patients > 20 years old who presented to the ED of Singapore General Hospital with chest pain between September 2010 and July 2015. Variables used included demographics, medical history, laboratory findings, heart rate variability (HRV), and heart rate n-variability (HRnV) parameters calculated from five to six-minute electrocardiograms (ECGs). The primary outcome was 30-day major adverse cardiac events (MACE), which included death, acute myocardial infarction, and revascularization within 30 days of ED presentation. We used eight machine learning dimensionality reduction methods and logistic regression to create different prediction models. We further excluded cardiac troponin from candidate variables and derived a separate set of models to evaluate the performance of models without using laboratory tests. Receiver operating characteristic (ROC) and calibration analysis was used to compare model performance.ResultsSeven hundred ninety-five patients were included in the analysis, of which 247 (31%) met the primary outcome of 30-day MACE. Patients with MACE were older and more likely to be male. All eight dimensionality reduction methods achieved comparable performance with the traditional stepwise variable selection; The multidimensional scaling algorithm performed the best with an area under the curve of 0.901. All prediction models generated in this study outperformed several existing clinical scores in ROC analysis.ConclusionsDimensionality reduction models showed marginal value in improving the prediction of 30-day MACE for ED chest pain patients. Moreover, they are black box models, making them difficult to explain and interpret in clinical practice.

Comparison of self-reported EDACS versus physician-reported EDACS for the triage of chest pain patients in the emergency department.

ObjectivesCurrently, there are no guidelines to help triage nurses identify high‐risk emergency department chest pain patients. Patient self‐reporting of Emergency Department Assessment of Chest Pain Score (EDACS) could facilitate more reliable triage compared to nursing gestalt, but this novel concept is untested. This study hypothesizes that because EDACS requires minimal clinical gestalt to derive, self‐reported EDACS (S‐EDACS) at triage is likely to correlate well with traditional physician‐reported EDACS (P‐EDACS) and have potential application as a triage tool.MethodsThis single‐center pilot prospective cohort study analyzed 60 patients who completed a self‐reported questionnaire upon triage to determine their S‐EDACS. This was matched against P‐EDACS, derived from an identical questionnaire completed by the blinded treating physician. Secondary endpoint of major adverse cardiovascular events (MACE) within 30 days (all‐cause mortality, myocardial infarction, coronary revascularization) was assessed by 2 blinded emergency physicians who independently reviewed the electronic medical records. S/P‐EDACS also were benchmarked against nursing gestalt (based on triage to low/high‐acuity areas) and emergency physician gestalt (disposition and admitting/discharge diagnoses).ResultsThere was perfect agreement between S/P‐EDACS in this study (K = 1.00). Fifteen patients (25.0%) had minor discordances in their absolute S/P‐EDACS that did not affect risk stratification. Of these, 11/15 (73.3%) had higher S‐EDACS, suggesting S‐EDACS is more likely to safely overcall MACE risk. S‐EDACS outperformed nursing gestalt, triaging a greater proportion of patients (71.7% vs 35.0%) as low risk without compromising patient safety, and demonstrated similar accuracy as emergency physician gestalt.ConclusionS‐EDACS strongly correlates with P‐EDACS with perfect agreement and has potential to be used as a triage tool.

Low diagnostic yield of ST elevation myocardial infarction amplitude criteria in chest pain patients at the emergency department

Objectives To evaluate the diagnostic yield of the ECG criteria for ST-elevation myocardial infarction in a large cohort of emergency department chest pain patients, and to determine whether extended ECG criteria or reciprocal ST depression can improve accuracy. Design: Observational, register-based diagnostic study on the accuracy of ECG criteria for ST-elevation myocardial infarction. Between Jan 2010 and Dec 2014 all patients aged ≥30 years with chest pain who had an ECG recorded within 4 h at two emergency departments in Sweden were included. Exclusion criteria were: ECG with poor technical quality; QRS duration ≥120 ms; ECG signs of left ventricular hypertrophy; or previous coronary artery bypass surgery. Conventional and extended ECG criteria were applied to all patients. The main outcome was acute myocardial infarction (AMI) and an occluded/near-occluded coronary artery at angiography. Results: Finally, 19932 patients were included. Conventional ECG criteria for ST elevation myocardial infarction were fulfilled in 502 patients, and extended criteria in 1249 patients. Sensitivity for conventional ECG criteria in diagnosing AMI with coronary occlusion/near-occlusion was 17%, specificity 98% and positive predictive value 12%. Corresponding data for extended ECG criteria were 30%, 94% and 8%. When reciprocal ST depression was added to the criteria, the positive predictive value rose to 24% for the conventional and 23% for the extended criteria. Conclusions: In unselected chest pain patients at the emergency department, the diagnostic yield of both conventional and extended ECG criteria for ST-elevation myocardial infarction is low. The PPV can be increased by also considering reciprocal ST depression.

99 Delta Troponin Does Not Predict a Major Cardiac Event in Patients With Renal Dysfunction

Determine if delta conventional or delta high sensitivity troponin add value in determining a major adverse coronary event (MACE) in renal patients with an elevated troponin. This retrospective cohort study of emergency department (ED) patients diagnosed with chest pain, angina, unstable angina, or myocardial infarction (ICD-10 codes R07, I20, I21) was conducted from January 1 to November 27, 2018 at a tertiary care academic ED center (annual volume 95,000). Inclusion criteria consisted of: 1) renal dysfunction (defined as an eGFR < 60 ml/min/1.72m2); 2) initial positive troponin; 3) at least two troponin measurements within 24 hours. The Roche® 4th generation conventional troponin (cTnT) was used until June 12 with a positive troponin defined as ≥0.06ng/mL. Then, the Roche® 5th generation high sensitivity troponin (hsTnT) was used with a positive troponin defined as ≥52ng/L. A significant delta troponin was defined as a rise or fall of at least 20% from the initial troponin. All patients were then reviewed for a MACE, defined as cardiac-related mortality, need for a coronary stent or bypass graft, or clinically diagnosed type 1 or 2 myocardial infarction within 6 weeks of initial ED visit. 6,360 ED chest pain patients were included in the study. 1,213 patients had renal dysfunction with eGFR < 60 (mean eGFR 38.8 ± 17), and of these ED chest pain renal patients, 303 patients (25%) had a positive troponin. 18 patients were excluded for having a single troponin. In total, 285 patients met inclusion criteria. For the 114 renal patients with a positive cTnT (69 ±13 years old, 62% male), 54 had a MACE (prevalence = 47.3%) with only 27 patients having significant delta troponins (PPV = 65.9%) (see Table). In the 60 patients without a MACE, 46 patients had insignificant delta troponins (NPV = 63%). The positive likelihood ratio (+LR) of a delta cTnT detecting a MACE was very low and nearly approached insignificance at 2.14 (95% CI 1.26, 3.64). The negative likelihood ratio (-LR) of a delta cTnT to exclude a MACE also nearly approached insignificance at 0.65 (95% 0.48, 0.88). For the 171 renal patients with a positive hsTnT (70±14 years, 58% male), 69 had a MACE (prevalence = 40.4%) with only 23 patients having significant delta troponins (PPV = 65.7%). In the 102 patients without a MACE, 90 patients had insignificant delta troponins (NPV = 66.2%). The +LR of a delta hsTnT to detect a MACE was very low and nearly approached insignificance at 2.83 (95% CI 1.51, 5.31). The -LR of a delta hsTnT to exclude a MACE also nearly approached insignificance at 0.70 (95% CI 0.63, 0.91). The Fourth Universal Definition for Myocardial Infarction recommends a rise or fall of cardiac troponin greater than 20% to diagnose a myocardial infarction in renal dysfunction patients. However, this study of renal patients with elevated troponin levels shows that measuring a delta using either conventional or high sensitivity troponin does not add value to determine a MACE.Tabled 1Conventional and High Sensitivity Delta Troponins in Predicting MACERenal dysfunct ED CP+TnT# PtsSensSpecifPPV (95% CI)NPV (95% CI)+LR (95% CI)-LR (95% CI)Delta cTnT11450%76.7%65.9% (+/-1.9%)63.0% (+/- 1.9%)2.14 [1.26, 3.64]0.65 [0.48, 0.88]Delta hsTnT17133.3%88.2%65.7% (+/- 1.9%)66.2% (+/- 1.9%)2.83 [1.51, 5.31]0.76 [0.63, 0.91] Open table in a new tab

272EMF Using Monocyte Chemoattractant Protein-1 to Predict Adverse Cardiovascular Events among Emergency Department Chest Pain Patients

272EMF Using Monocyte Chemoattractant Protein-1 to Predict Adverse Cardiovascular Events among Emergency Department Chest Pain Patients

271EMF Advancing Emergency Department Chest Pain Risk Stratification With Monocyte Chemoattractant Protein-1 and High-Sensitivity Troponin

The History, Electrocardiogram, Age, Risk factor, and Troponin Pathway (HEART Pathway) risk stratifies 50-55% of emergency department (ED) chest pain patients as non-low-risk and recommends that they receive observation and stress testing. The objective of this study was to determine if two novel biomarkers, MCP-1 and hs-cTnT, alone or in combination, can achieve ≥ 99% sensitivity and negative predictive value for 90-day MACE among non-low-risk HEART Pathway patients. A case-control study was nested within a multicenter, prospective study (STOP-CP). ED patients ≥ 21 years old who presented to the ED with symptoms concerning for acute coronary syndrome who had a HEAR score ≥ 4 or known coronary artery disease (CAD), a non-ischemic ECG, and non-elevated contemporary troponins at 0- and 3-hours were eligible for inclusion. Cases (N=40) were patients with 90-day MACE events (all-cause mortality, myocardial infarction, or revascularization). Controls (N=179) were patients without MACE who were selected based on frequency matching using age, sex, race, and numeric HEAR score or the presence of known CAD. Receiver operator curves were used to assess biomarker performance at various cut-points. Sensitivity and specificity were calculated. The prevalence of MACE in non-low-risk patients in the STOP-CP study was 6.5% (40/618). This was used for determining negative predictive value (NPV) and positive predictive value (PPV). Among the 40 cases and 179 controls, there was no significant difference in age (p=0.90), sex (p=1.00), race (p=0.91), or HEAR score/presence of CAD (p=0.89). An MCP-1 cut-point of 194 pg/mL resulted in 50.0% (95% CI 33.8-66.2%) sensitivity and 93.1% (95% CI 90.5-95.0%) NPV for 90-day MACE. A MCP-1 measure of 238 pg/mL had a 30.0% (95% CI 16.6-46.5%) sensitivity and 93.5% (95% CI 92.0-94.7%) NPV. A hs-cTnT result of 11 ng/L was 60.0% (95% CI 43.3-75.1) sensitive with a NPV of 95.7% (95% CI 93.8-97.1). At a hs-cTnT cut-point of 19 ng/L, sensitivity was 30.0% (95% CI 16.6-46.5%) with a 94.5% (95% CI 93.3-95.5%) NPV. These data suggest that MCP-1 is not a useful biomarker for risk-stratifying ED patients with non-low-risk chest pain. Hs-cTnT may be a useful biomarker for enabling additional patients to be classified as low-risk and discharged without lengthy evaluations.