Predicting whether patients in an acute medical unit are physiologically fit-for-discharge using machine learning: A proof-of-concept

INTRODUCTION

Delays in discharging patients from Acute Medical Units hamper patient flows throughout the hospital. The decision to discharge a patient is mainly based on the patients' physiological condition, but may vary between physicians. An objective decision-support system based on patients' physiological data may help minimizing unnecessary delays in discharge. The aim of this proof-of-concept study is to assess the feasibility of predicting whether patients in an Acute Medical Unit are physiologically fit-for-discharge using machine learning with commonly available hospital data. Furthermore, this study investigated how long before actual time of discharge from the Acute Medical Unit we could predict discharge fitness. Also, the predictive importance of features extracted from these data was assessed.

METHODS

Electronic Medical Records of patients who participated in a Randomized Controlled Trial conducted in an Acute Medical Unit were used retrospectively (N = 199). Only commonly available hospital data were used. Logistic Regression and Random Forest models were applied to predict every hour whether patients were physiologically fit-for-discharge. Nested 5-fold cross-validation with 5 repeats was used to optimize the model hyperparameters and to estimate the predictive performances.

RESULTS

Physiological discharge fitness was predictable with reasonable performance for Logistic Regression (mean AUROC: 0.67) and Random Forest (mean AUROC: 0.69). For an intuitively chosen classification threshold of 0.8, mean specificity was 93.3 % and sensitivity 14.1 %. Models could predict physiological discharge fitness more than 24 h earlier than actual time of discharge for most patients who were correctly predicted to be fit-for-discharge. Patient characteristics, vital signs and laboratory results were shown to be important predictors.

CONCLUSION

This proof-of-concept study showed that it is feasible to predict with machine learning whether patients in an Acute Medical Unit are physiologically fit-for-discharge using commonly available hospital data.

Safety and efficiency of implementation of high-sensitivity troponin T in the assessment of emergency department patients with cardiac chest pain

BACKGROUND

For emergency department (ED) patients with cardiac chest pain, introduction of high-sensitivity troponin (hsTnT) pathways has been associated with reductions in length of stay of less than 1 h.

METHODS

At two urban Canadian sites, we introduced hsTnT on January 26, 2016. While the prior diagnostic algorithm required troponin testing at 0 and 6 h, serial hsTnT serial testing was conducted at 0 and 3 h. We identified consecutive patients who presented with cardiac chest pain from January 1, 2015, to March 31, 2017, along with 30-day outcomes. The primary outcome was a missed 30-day major adverse cardiac event, (MACE) defined as death, revascularization, or readmission for myocardial infarction occurring in a patient-discharged home with a minimizing diagnosis and without cardiac-specific follow-up. Secondary outcomes included admission rate, ED length of stay, and MACE. We compared pre- and post- implementation periods using descriptive methods and repeated this analysis in patients with noncardiac chest pain.

RESULTS

We collected 5585 patients with cardiac chest pain, (2678 pre- and 2907 post-introduction) and 434 had (7.8%, 95% CI 7.1 to 8.5%) MACE, with 1 missed MACE. (0.2%, 95% CI 0.04 to 1.3%). Admission rate was stable at 24.1% pre- and 23.7% while median length of stay decreased from 464 to 285 min, a difference of 179 min. (95% CI 61 to 228 min). For 11,611 patients with noncardiac chest pain, admission rate (9%) and length of stay (191 versus 193 min) remained constant.

CONCLUSIONS

Implementation of hsTnT for evaluation of ED chest pain patients was safe and associated with a 3-h decrease in length of stay.

Self-Administration of Aspirin After Chest Pain for the Prevention of Premature Cardiovascular Mortality in the United States: A Population-Based Analysis

BACKGROUND

Aspirin, an effective, low-cost pharmaceutical, can significantly reduce mortality if used promptly after acute myocardial infarction (AMI). However, many AMI survivors do not receive aspirin within a few hours of symptom onset. Our aim was to quantify the mortality benefit of self-administering aspirin at chest pain onset, considering the increased risk of bleeding and costs associated with widespread use.

METHODS AND RESULTS

We developed a population simulation model to determine the impact of self-administering 325 mg aspirin within 4 hours of severe chest pain onset. We created a synthetic cohort of adults ≥ 40 years old experiencing severe chest pain using 2019 US population estimates, AMI incidence, and sensitivity/specificity of chest pain for AMI. The number of annual deaths delayed was estimated using evidence from a large, randomized trial. We also estimated the years of life saved (YOLS), costs, and cost per YOLS. Initiating aspirin within 4 hours of severe chest pain onset delayed 13 016 (95% CI, 11 643-14 574) deaths annually, after accounting for deaths due to bleeding (963; 926-1003). This translated to an estimated 166 309 YOLS (149391-185 505) at the cost of $643 235 (633 944-653 010) per year, leading to a cost-effectiveness ratio of $3.70 (3.32-4.12) per YOLS.

CONCLUSIONS

For <$4 per YOLS, self-administration of aspirin within 4 hours of severe chest pain onset has the potential to save 13 000 lives per year in the US population. Benefits of reducing deaths post-AMI outweighed the risk of bleeding deaths from aspirin 10 times over.

Age differences in the safety and effectiveness of the HEART Pathway accelerated diagnostic protocol for acute chest pain

BACKGROUND

The HEART Pathway is a validated protocol for risk stratifying emergency department (ED) patients with possible acute coronary syndrome (ACS). Its performance in different age groups is unknown. The objective of this study is to evaluate its safety and effectiveness among older adults.

METHODS

A pre-planned subgroup analysis of the HEART Pathway implementation study was conducted. This prospective interrupted time series accrued adult ED patients with possible ACS who were without ST-elevation across three US sites from 11/2013-01/2016. After implementation, providers prospectively used the HEART Pathway to stratify patients as low-risk or non-low-risk. Patients were classified as older adults (≥65 years), middle-aged (46-64 years), and young (21-45 years). Primary safety and effectiveness outcomes were 30-day death or MI and hospitalization at 30 days, determined from health records, insurance claims, and death index data. Fisher's exact test compared low-risk proportions between groups. Sensitivity for 30-day death or MI and adjusted odds ratios (aORs) for hospitalization and objective cardiac testing were calculated.

RESULTS

The HEART Pathway implementation study accrued 8474 patients, of which 26.9% (2281/8474) were older adults, 45.5% (3862/8474) middle-aged, and 27.5% (2331/8474) were young. The HEART Pathway identified 7.4% (97/1303) of older adults, 32.0% (683/2131) of middle-aged, and 51.4% (681/1326) of young patients as low-risk (p < 0.001). The HEART Pathway was 98.8% (95% CI 97.1-100) sensitive for 30-day death or MI among older adults. Following implementation, the rate of 30-day hospitalization was similar among older adults (aOR 1.25, 95% CI 1.00-1.55) and cardiac testing increased (aOR 1.25, 95% CI 1.04-1.51).

CONCLUSION

The HEART Pathway identified fewer older adults as low-risk and did not decrease hospitalizations in this age group.

Development of a prediction model for clinically important outcomes of acute diverticulitis

OBJECTIVE

Acute diverticulitis (AD) is a common disease with various outcomes. When AD is diagnosed in the emergency department (ED), the ED clinician must determine the patient's treatment strategy whether the patient can be discharged, needs to be admitted to the general ward, ICU, or needs surgical consultation. This study aimed to identify potential risk factors for clinically important outcomes (CIOs) and to develop a prediction model for CIOs in AD to aid clinical decision making in the ED.

METHODS

Retrospective data from between 2013 and 2017 in an ED in an urban setting were reviewed for adult AD. Potential risk factors were age, sex, past medical history, symptoms, physical exams, laboratory results, and imaging results. A CIO was defined as a case with one of the following outcomes: hospital death, ICU admission, surgery or invasive intervention, and admission for 7 or more days. The prediction model for CIOs was developed using potential risk factors. Model discrimination and calibration were assessed using the area under the curve (AUC) and 95% confidence intervals (CIs) and the Hosmer-Lemeshow (HL) test, respectively. Model validation was conducted using 500 random bootstrap samples.

RESULTS

Of the final 337 AD patients, 63 patients had CIOs. Six potential factors (age, abdominal pain (≥ 3 days), anorexia, rebound tenderness, white blood cell count (> 15,000/μl), C-reactive protein (> 10 mg/dL), and CT findings of a complication) were used for the final model. The AUC (95% CI) for CIOs was 0.875 (0.826-0.923), and χ² was 2.969 (p-value = 0.936) with the HL test. Validation using bootstrap samples resulted in an optimism-corrected AUC of 0.858 (0.856-0.861).

CONCLUSION

A prediction model for clinically important outcomes of AD visiting a single ED showed good discrimination and calibration power with an acceptable range.

The Diagnostic Accuracy of the Emergency Department Assessment of Chest Pain (EDACS) Score: A Systematic Review and Meta-analysis

STUDY OBJECTIVE

We evaluate current evidence for the diagnostic accuracy and safety of the Emergency Department Assessment of Chest Pain Score (EDACS) for patients presenting to the emergency department (ED) with possible acute coronary syndromes.

METHODS

MEDLINE, EMBASE, and Cochrane databases were searched for publications reporting data on the EDACS score. No date restrictions were used. Two independent researchers assessed studies for eligibility, bias, and quality. The primary outcome was major adverse cardiac events occurring within 30 days. Heterogeneity was assessed and data were pooled by meta-analysis using a random-effects model.

RESULTS

Eight diagnostic test accuracy studies including 11,578 patients and 1 randomized controlled trial including 558 patients were eligible for inclusion. On meta-analysis, the EDACS score had a pooled sensitivity of 96.1% (95% confidence interval 89.6% to 98.6%) and specificity of 61.1% (95% confidence interval 55.5% to 66.3%). A total of 55.0% of patients (n=6,370/11,578) were identified as low risk and eligible for early discharge. Sixty-two patients (0.54%) identified as low risk had an outcome of major adverse cardiac events within 30 days.

CONCLUSION

The EDACS score identified greater than 50% of patients with suspected acute coronary syndrome as suitable for discharge after serial troponin sampling during 2 hours. Sensitivity for major adverse cardiac events was relatively high overall and may be acceptable to clinicians.

Effective combination of isolated symptom variables to help stratifying acute undifferentiated chest pain in the emergency department

BACKGROUND

Symptom is still indispensable for the stratification of chest pain in the emergency department. However, it is a sophisticated aggregation of several aspects of characteristics and effective combination of those variables remains deficient. We aimed to develop and validate a chest pain symptom score (CPSS) to address this issue.

HYPOTHESIS

The CPSS may help stratifying acute undifferentiated chest pain in ED.

METHODS

Patients with non-ST segment elevation chest pain and negative cardiac troponin (cTn) over 3 hours after symptom onset were consecutively recruited as the derivation cohort. Logistic regression analyses identified statistical predictors from all symptom aspects for 30-day acute myocardial infarction (AMI) or death. The performance of CPSS was compared with the symptom classification methods of the history variable in the history, electrocardiograph, age, risk factors, troponin (HEART) score. This new model was validated in a separated cohort of patients with negative cTn within 3 hours.

RESULTS

Seven predictors in four aspects of chest pain symptom were identified. The CPSS was an independent predictor for 30-day AMI or death (P < 0.001). In the derivation (n = 1434) and validation (n = 976) cohorts, the expected and observed event rates were well calibrated (Hosmer-Lemeshow test P > 0.30), and the c-statistics of CPSS were 0.72 and 0.73, separately, significantly better than the previous history classifications in HEART score (P < 0.001). Replacing the history variable with the CPSS improved the discrimination and risk classification of HEART score significantly (P < 0.001).

CONCLUSIONS

The effective combination of isolated variables was meaningful to make the most stratification value of symptoms. This model should be considered as part of a comprehensive strategy for chest pain triage.

Comparison of nine coronary risk scores in evaluating patients presenting to hospital with undifferentiated chest pain

INTRODUCTION

We compared performance of nine risk scores for coronary heart disease (CHD) among patients presenting to an emergency department (ED) with undifferentiated chest pain of possible coronary origin.

METHODS

A retrospective study was undertaken of adult patients presenting with chest pain to atertiary hospital ED with no electrocardiographs or troponin results diagnostic of ischemic chest pain (ICP) or acute coronary syndrome at ED presentation, and no clearly evident noncoronary diagnosis. Risk scores were applied using cut-points distinguishing low- from high-risk patients according to discharge diagnosis of noncardiac chest pain (NCCP) or ICP, respectively. A lower odds ratio (OR) for ICP denoted lower risk for ICP. Score performance was compared using area under receiver-operator characteristic curves (AUC) and predictive values.

RESULTS

A total of 401 patients were studied, of whom 123 (30.7%) had ICP as final diagnosis. Among the nine risk scores, those with greatest ability to detect low-risk patients were The North American Chest Pain Rule (NACPR) score (OR=0.35, 95% CI=0.27-0.46); History, ECG, Age, Risk Factors, and Troponin (HEART) score (OR=0.43; 95% CI=0.35-0.52); and Thrombolysis in Myocardial Infarction (TIMI) score (OR=0.49; 95% CI=0.41-0.58). Discrimination between patients with NCCP and those with ICP was greatest for HEART score (AUC=0.82; 95% CI=0.78-0.86) and lowest for Accelerated Diagnostic Protocol to Assess Patients with Chest Pain Symptoms Using Contemporary Troponins (ADAPT) score (AUC=0.63; 95% CI=0.58-0.69). In excluding ICP, ADAPT had negative predictive value (NPV) 100% (miss rate 0%) but classified only 1.7% of patients as low risk, compared to NACPR with NPV 98% (miss rate 2%), classifying 10.2% as low risk, and HEART with NPV 94% (miss rate 6%), classifying 32.4% as low risk.

CONCLUSION

The NACPR risk score maximized yield of low-risk patients with lowest miss rate for ICP, while HEART score classified highest proportion of low-risk patients but with a higher miss rate.

The HEART score in predicting major adverse cardiac events in patients presenting to the emergency department with possible acute coronary syndrome: protocol for a systematic review and meta-analysis

BACKGROUND

Acute coronary syndrome (ACS) is a common, sometimes difficult to diagnose spectrum of diseases occurring after abrupt reduction in blood flow through a coronary artery. Given the diagnostic challenge, it is sensible for emergency physicians to have an approach to prognosticate patients with possible ACS. Multiple prediction models have been developed to help identify patients at increased risk of adverse outcomes. The HEART score is the first model to be derived, validated, and undergo clinical impact studies in emergency department (ED) patients with possible ACS.

OBJECTIVE

To develop a protocol for a prognostic systematic review of the literature evaluating the HEART score as a predictor of major adverse cardiac events (MACE) in patients presenting to the ED with possible ACS.

METHODS/DESIGN

This protocol is reported according to the PRISMA-P statement and is registered on PROSPERO. All methodological tools to be used are endorsed by the Cochrane Prognosis Methods Group. Pre-defined eligibility criteria are provided. Multiple strategies will be used to identify potentially relevant studies. Studies will be selected and data extracted using standardised forms based on the CHARMS checklist. The QUIPS tool will be used to assess the risk of bias within individual studies. Outcome measures will include prevalence, risk ratio, and absolute risk reduction for MACE within 6 weeks of ED evaluation, comparing HEART scores 0-3 versus 4-10. HEART score prognostic performance will be evaluated with the concordance (C) statistic (model discrimination), observed to expected events ratio (model calibration), and a decision curve analysis. Reporting biases and methodological, clinical, and statistical heterogeneity will be scrutinised. Unless deemed inappropriate, a meta-analysis and pre-defined subgroup and sensitivity analyses will be performed. Overall judgements about evidence quality and strength of recommendations will be summarised using the GRADE approach.

DISCUSSION

This review will identify, select, and appraise studies evaluating the prognostic performance of the HEART score, producing results of interest to emergency physicians. These results may encourage shared clinical decision-making in the ED by facilitating risk communication with patients and health care providers.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2017 CRD42017084400 .

High-Sensitivity Cardiac Troponin-Based Strategies for the Assessment of Chest Pain Patients-A Review of Validation and Clinical Implementation Studies

BACKGROUND

The introduction of high-sensitivity cardiac troponin (hs-cTn) assays has improved the early assessment of chest pain patients. A number of hs-cTn-based algorithms and accelerated diagnostic protocols (ADPs) have been developed and tested subsequently. In this review, we summarize the data on the performance and clinical utility of these strategies.

CONTENT

We reviewed studies investigating the diagnostic and prognostic performance of hs-cTn algorithms [level of detection (LoD) strategy, 0/1-h, 0/2-h, and 0/3-h algorithms) and of hs-cTn-based ADPs, together with the implications of these strategies when implemented as clinical routine. The LoD strategy, when combined with a nonischemic electrocardiogram, is best suited for safe rule-out of myocardial infarction and the identification of patients eligible for early discharge from the emergency department. The 0/1-h algorithms appear to identify most patients as being eligible for rule-out. The hs-cTn-based ADPs mainly focus on prognostic assessment, which is in contrast with the hs-cTn algorithms. They identify smaller proportions of rule-out patients, but there is increasing evidence from prospective studies on their successful clinical implementation. Such information is currently lacking for hs-cTn algorithms.

CONCLUSIONS

There is a trade-off between safety and efficacy for different hs-cTn-based strategies. This trade-off should be considered for the intended strategy, along with its user-friendliness and evidence from clinical implementation studies. However, several gaps in knowledge remain. At present, we suggest the use of an ADP in conjunction with serial hs-cTn results to optimize the early assessment of chest pain patients.

Achieving the earliest possible reperfusion in patients with acute coronary syndrome: a current overview

Acute coronary syndrome (ACS) remains one of the leading causes of mortality worldwide. Appropriate management of ACS will lead to a lower incidence of cardiac arrest. Percutaneous coronary intervention (PCI) is the first-line treatment for patients with ACS. PCI techniques have become established. Thus, the establishment of a system of health care in the prehospital and emergency department settings is needed to reduce mortality in patients with ACS. In this review, evidence on how to achieve earlier diagnosis, therapeutic intervention, and decision to reperfuse with a focus on the prehospital and emergency department settings is systematically summarized. The purpose of this review is to generate current, evidence-based consensus on scientific and treatment recommendations for health care providers who are the initial points of contact for patients with signs and symptoms suggestive of ACS.

Identification of coronary artery calcification can optimize risk stratification in patients with acute chest pain

BACKGROUND

The number of patients presenting to the emergency department (ED) with suspected acute coronary syndrome (ACS) is substantial. We tested whether identification of coronary artery calcium (CAC) can improve the negative predictive value (NPV) of clinical risk assessment for ACS in patients with acute chest pain.

METHODS AND RESULTS

We included 826 consecutive patients (mean age: 53±11years; 42% female) without known coronary artery disease (CAD) or initially elevated serum biomarkers, whom underwent non-contrast CT, to assess the CAC score, and CT angiography (CTA), to detect coronary stenosis. We analyzed the diagnostic performance of CAC and the Thrombolysis In Myocardial Infarction (TIMI) risk score for our primary outcomes (ACS and obstructive CAD). No CAC was found in 54% (n=444) of all patients, 63% (n=524) had a TIMI score of 0 and 40% (n=328) had both. The prevalence of obstructive CAD was 16% for ≥50% stenosis and 8.7% for ≥70% stenosis. The incidence of ACS was 7.9%, (MI=11, UAP=54). The NPV of CAC=0 was 99.5% for ACS. The NPV of a combination of TIMI score=0 and no CAC was 89% for any CAD (any plaque or stenosis) and 99.7% for ≥50% stenosis. A 100% NPV was found for ≥70% stenosis and ACS, correctly identifying 328 (40%) patients.

CONCLUSIONS

The exclusion of CAC, in combination with clinical risk assessment, has high clinical value in patients with acute chest pain, as it identifies patients at low risk for ACS and obstructive CAD more accurately as compared to clinical risk assessment alone.

Diagnostic Accuracy of a New High-Sensitivity Troponin I Assay and Five Accelerated Diagnostic Pathways for Ruling Out Acute Myocardial Infarction and Acute Coronary Syndrome

STUDY OBJECTIVE

This diagnostic accuracy study describes the performance of 5 accelerated chest pain pathways, calculated with the new Beckman's Access high-sensitivity troponin I assay.

METHODS

High-sensitivity troponin I was measured with presentation and 2-hour blood samples in 1,811 patients who presented to an emergency department (ED) in Australia. Patients were classified as being at low risk according to 5 rules: modified accelerated diagnostic protocol to assess patients with chest pain symptoms using troponin as the only biomarker (m-ADAPT), the Emergency Department Assessment of Chest Pain Score (EDACS) pathway, the History, ECG, Age, Risk Factors, and Troponin (HEART) pathway, the No Objective Testing Rule, and the new Vancouver Chest Pain Rule. Endpoints were 30-day acute myocardial infarction and acute coronary syndrome. Measures of diagnostic accuracy for each rule were calculated.

RESULTS

Data included 96 patients (5.3%) with acute myocardial infarction and 139 (7.7%) with acute coronary syndrome. The new Vancouver Chest Pain Rule and No Objective Testing Rule had high sensitivity for acute myocardial infarction (100%; 95% confidence interval [CI] 96.2% to 100% for both) and acute coronary syndrome (98.6% [95% CI 94.9% to 99.8%] and 99.3% [95% CI 96.1% to 100%]). The m-ADAPT, EDACS, and HEART pathways also yielded high sensitivity for acute myocardial infarction (96.9% [95% CI 91.1% to 99.4%] for m-ADAPT and 97.9% [95% CI 92.7% to 99.7%] for EDACS and HEART), but lower sensitivity for acute coronary syndrome (≤95.0% for all). The m-ADAPT, EDACS, and HEART rules classified more patients as being at low risk (64.3%, 62.5%, and 49.8%, respectively) than the new Vancouver Chest Pain Rule and No Objective Testing Rule (28.2% and 34.5%, respectively).

CONCLUSION

In this cohort with a low prevalence of acute myocardial infarction and acute coronary syndrome, using the Beckman's Access high-sensitivity troponin I assay with the new Vancouver Chest Pain Rule or No Objective Testing Rule enabled approximately one third of patients to be safely discharged after 2-hour risk stratification with no further testing. The EDACS, m-ADAPT, or HEART pathway enabled half of ED patients to be rapidly referred for objective testing.

Identifying Low-risk Patients for Early Discharge From Emergency Department Without Using Subjective Descriptions of Chest Pain: Insights From Providing Rapid Out of Hospital Acute Cardiovascular Treatment (PROACT) 3 and 4 Trials

BACKGROUND

Several accelerated diagnostic protocols (ADPs) have been developed to allow emergency department (ED) physicians to identify appropriate patients for safe early discharge after presentation with symptom of chest pain. Most ADPs require chest pain to be described and modify the algorithm based on the subjective chest pain characteristics. We investigated the performance of three established major ADPs simplified by eliminating the need for chest pain as a descriptor.

METHODS

We pooled patients from PROACT-3 and -4 trials, in which patients presenting to emergency medical services with chest pain or dyspnea were enrolled. The simplified Vancouver Chest Pain Rule (sVCPR), the simplified Emergency Department Assessment of Chest Pain Score (sEDACS) ADP and the Accelerated Diagnostic protocol to Assess Patients with chest pain using contemporary troponins as the only biomarker (ADAPT-ADP) were compared using the sensitivity, specificity, and positive and negative predictive values (NPV). The primary outcome of interest was 30-day major adverse cardiac events (MACE); the diagnosis of acute coronary syndrome (ACS) occurring within 30 days after ED presentation was also explored.

RESULTS

A total of 1,081 patients were included (median age = 67 years, 53% male, median GRACE score = 113) of which 222 ACS diagnoses and 150 cardiac events occurred within 30 days after index ED presentation. The sVCPR, sEDACS ≥ 3, and ADAPT-ADP, respectively, identified 9.7, 13.3, and 4.1% of patients as low risk with a sensitivity and NPV of 100% for the primary outcome of 30-day MACE. The sEDACS-ADP identified 24.2% of patients as low risk with a cut-point score of 4 (sensitivity of 98.0% and NPV of 98.8%). The sVCPR, sEDACS ≥ 3, and ADAPT-ADP, respectively, had NPVs of 98.1, 95.8, and 93.3% in identifying patients at higher risk of ACS diagnosis within 30 days after index ED visit.

CONCLUSION

The diagnostic protocols performed well without their chest pain characteristics component. Further studies are suggested to explore the performance of ADPs when these simplified ADPs are combined with high-sensitive troponin assays.

Impact of comorbidities by age on symptom presentation for suspected acute coronary syndromes in the emergency department

BACKGROUND

It is estimated half of acute coronary syndrome (ACS) patients have one or more associated comorbid conditions.

AIMS

Aims were to: 1) examine the prevalence of comorbid conditions in patients presenting to the emergency department with symptoms suggestive of ACS; 2) determine if comorbid conditions influence ACS symptoms; and 3) determine if comorbid conditions predict the likelihood of receiving an ACS diagnosis.

METHODS

A total of 1064 patients admitted to five emergency departments were enrolled in this prospective study. Symptoms were measured on presentation to the emergency department. The Charlson Comorbidity Index (CCI) was used to evaluate group differences in comorbidity burden across demographic traits, risk factors, clinical presentation, and diagnosis.

RESULTS

The most prominent comorbid conditions were prior myocardial infarction, diabetes without target organ damage, and chronic lung disease. In younger ACS patients, higher CCI predicted less chest pain, chest discomfort, unusual fatigue and a lower number of symptoms. In older ACS patients, higher CCI predicted more chest discomfort, upper back pain, abrupt symptom onset, and greater symptom distress. For younger non-ACS patients, higher CCI predicted less chest pain and symptom distress. Higher CCI was associated with a greater likelihood of receiving an ACS diagnosis for younger but not older patients with suspected ACS.

CONCLUSIONS

Younger patients with ACS and higher number of comorbidities report less chest pain, putting them at higher risk for delayed diagnosis and treatment since chest pain is a hallmark symptom for ACS.

State-of-the-Art Evaluation of Emergency Department Patients Presenting With Potential Acute Coronary Syndromes

It is well established that clinicians cannot use clinical judgment alone to determine whether an individual patient who presents to the emergency department has an acute coronary syndrome. The history and physical examination do not distinguish sufficiently between the many conditions that can cause acute chest pain syndromes. Cardiac risk factors do not have sufficient discriminatory ability in symptomatic patients presenting to the emergency department. Most patients with non-ST-segment-elevation myocardial infarction do not present with electrocardiographic evidence of active ischemia. The improvement in cardiac troponin assays, especially in conjunction with well-validated clinical decision algorithms, now enables the clinician to rapidly exclude myocardial infarction. In patients in whom unstable angina remains a concern or there is a desire to evaluate for underlying coronary artery disease, coronary computed tomography angiography can be used in the emergency department. Once a process that took ≥24 hours, computed tomography angiography now can rapidly exclude myocardial infarction and coronary artery disease in patients in the emergency department.

Validation of the new Vancouver Chest Pain Rule in Asian chest pain patients presenting at the emergency department

Objectives

The new Vancouver Chest Pain (VCP) Rule recommends early discharge for chest pain patients who are at low risk of developing acute coronary syndrome (ACS), and thus can be discharged within 2 hours of arrival at the emergency department (ED). This study aimed to assess the performance of the new VCP Rule for Asian patients presenting with chest pain at the ED.

Methods

This prospective cohort study involved patients attended to at the ED of a large urban centre. Patients of at least 25 years old, presenting with stable chest pain and a non-diagnostic ECG, and with no history of active coronary artery disease were included in the study. The main outcome measures were cardiac events, angioplasty, or coronary artery bypass within 30 days of enrolment.

Results

The study included 1690 patients from 27 August 2000 to 1 May 2002, with 661 patients fulfilling the VCP criteria. Of those for early discharge, 24 had cardiac events and 13 had angioplasty or bypass at 30 days, compared to 91 and 41, respectively, for those unsuitable for discharge. This gave the rule a sensitivity of 78.1% for cardiac events, including angioplasty and bypass. Specificity was 41.0%, and negative predictive value (NPV) was 94.4%.

Conclusion

We found the new VCP Rule to have moderate sensitivity and poor specificity for adverse cardiac events in our population. With an NPV of less than 100%, this means that a small proportion of patients sent home with early discharge would still have adverse cardiac events.