Variance Cardiography for Emergency Department Evaluation of Chest Pain Patients

Objective: To determine the test performance of 24–lead variance cardiography (VC), an ECG technique that measures QRS morphologic variability, for ED evaluation of chest pain associated with coronary artery disease (CAD).
Methods: A prospective, single–blind study of VC was performed in a community teaching hospital ED. All chest pain patients (>30 years of age) who, after initial emergency physician evaluation, were believed to have pain of potential cardiac etiology and were admitted to the hospital were eligible. Exclusion criteria included obvious noncardiac etiology for discomfort, bundle–branch block, atrial fibrillation, and incomplete subsequent cardiac evaluation. After initial evaluation and stabilization, VC was obtained. The numerical output of VC was a CAD index (CADI). Serum myoglobin and creatine kinase (CK)–MB levels were obtained at the time of presentation and after one, two, and six hours. Hospital records were reviewed to determine final diagnosis and in–hospital evaluation results.
Results: Fifty–two of 75 eligible patients had complete data. Final diagnoses were as follows: 27/52 (52%), noncardiac; 13/52 (25%), acute myocardial infarction (AMI); and 12/52 (23%), unstable angina due to CAD. Twenty–three percent (12/52) of the patients had CADIs < 75. Eleven of these were found to have noncardiac origins for their chest pain. The twelfth patient had a 12–lead ECG revealing AMI and had been given thrombolytic therapy with subsequent reperfusion prior to VC. Using a CADI < 75 as the cutoff for a negative study, VC alone had a negative predictive value of 92%, a sensitivity of 96%, a positive predictive value of 60%, and a specificity of 41%.
Conclusion: A CADI < 75, in addition to clinical impression and initial ECG, may identify chest pain patients who do not have significant CAD. Further prospective assessment of VC is warranted.     

Adverse Cardiac Events in Emergency Department Patients with Chest Pain Six Months after a Negative Inpatient Evaluation for Acute Coronary Syndrome

OBJECTIVE: To evaluate the impact of the diagnostic test setting-inpatient versus outpatient-on adverse cardiac events (ACEs) after six months in emergency department (ED) patients with chest pain who were admitted to the hospital and subsequently had a negative evaluation for acute coronary syndrome (ACS). METHODS: The authors retrospectively studied a consecutive sample of ED patients with chest pain over a nine-month period. All patients were admitted to the hospital and underwent negative evaluations for ACS, defined as the absence of diagnostic changes on serial electrocardiograms or cardiac markers (creatine kinase-MB and troponin T), and a negative diagnostic cardiac study. Subjects were classified according to cardiac diagnostic study setting-either inpatient or outpatient. Diagnostic testing included exercise treadmill, angiography, stress echocardiography, or stress thallium scans. Acute cardiac events at six months were defined as cardiac death, myocardial infarction, unstable angina, cardiac arrest, or emergent revascularization. RESULTS: The six-month rate of ACEs among 157 subjects was 14%, with 2% cardiac mortality. The outpatient group had higher ACE risk when compared with the inpatient group using multivariate logistic regression, both for the entire cohort (OR 3.5, p < 0.03) and for a subgroup excluding patients with prior coronary artery disease (OR 6.7, p < 0.05). The outpatient group included 19 of 52 (37%) noncompliant subjects who did not receive a diagnostic study. CONCLUSIONS: Long-term cardiac morbidity of patients after a negative ACS evaluation may be higher than previously thought. Risk of ACE is significantly higher in subjects scheduled for outpatient diagnostic tests. Inpatient diagnostic testing is justified for subjects at risk for poor compliance.     

Emergency Department Evaluation of Chest Pain Using Exercise Stress Echocardiography

OBJECTIVE: Patients with a low risk of coronary artery disease (CAD) presenting to the emergency department (ED) with chest pain pose a diagnostic dilemma because a small percentage will suffer an acute myocardial infarction (MI) and sudden death. The authors conducted this study to determine whether exercise stress echocardiography (ESE) could be used to further support the safe discharge of these low-risk patients. METHODS: A convenience sample of patients > or =30 years of age without a prior cardiac history who presented to an academic community hospital with chest pain, normal initial creatine kinase, and electrocardiography without ischemic changes underwent ESE within 6 +/- 1.7 hours (mean +/- SD). Abnormal ESE was defined as regional wall motion abnormality at rest or after exercise. The ED disposition and three- and six-month follow-up for cardiac events were recorded. This was a prospective observational cohort study. RESULTS: Of a total of 149 eligible patients, 145 completed the study. The mean age (+/-SD) was 47 +/- 9 years; 56% were male. No adverse events were noted during ESE. Seven patients (5%) had abnormal ESE (2 with rest wall motion abnormalities and 5 with exercise-induced wall motion abnormalities). Five of the seven underwent cardiac catheterization; three had CAD. All patients received telephone follow-up at three months and six months. Of the 138 patients with a normal ESE, all were free of cardiac events at three months. One patient had a non-Q-wave MI at six months (negative predictive value = 99.3%, 95% CI = 97.8% to 100%). CONCLUSIONS: Exercise stress echocardiography can be used to evaluate low-risk chest pain patients in the ED. Patients with a normal ESE may be considered for discharge with minimal risk of sequelae.     

Utility of HEART Pathway in Identifying Low-Risk Chest Pain in Emergency Department

BackgroundChest pain is a common presenting symptom in the emergency department (ED). The HEART (history, electroencephalogram [ECG], age, risk factors, and troponin I) score, with addition of troponin at 3 h, helps to determine appropriate risk stratification of the patients.ObjectiveThis study evaluated the utility of the HEART pathway as a decision aid designed for risk stratification of patients with acute-onset chest pain for early and safe disposition.MethodsThis was a prospective observational study done in a tertiary care center. Focused history, 12-lead ECG, and baseline troponin I level on arrival and at hour 3 were recorded. Subjects were classified as low risk (HEART score 0–3) or high risk (HEART score ≥ 4). Patients with a HEART score of 0–3 with negative troponin I at 3 h were discharged and were followed up for major adverse cardiac events (MACEs) within 30 days of ED presentation.ResultsA total of 250 patients were screened for the study, of which 151 were included for the final analysis. One hundred and two patients (68%) were male and 54% of patients were younger than 45 years. HEART scores of 0 (n = 16), 1 (n = 43), 2 (n = 44), and 3 (n = 48) were observed. There was only 1 MACE (0.7%) in 30 days after ED discharge in the study population. The mean length of ED stay in the low-risk group was 4.5 h.ConclusionsLow-risk patients, as per the HEART pathway, can be discharged safely from the ED, which reduces ED stay and health care resource use.     

Application of the TIMI Risk Score for Unstable Angina and Non-ST Elevation Acute Coronary Syndrome to an Unselected Emergency Department Chest Pain Population

Objectives: Patients presenting with chest pain or related symptoms suggestive of myocardial ischemia, without ST‐segment elevation (NSTE) on their presenting electrocardiograms, often present a diagnostic challenge in the emergency department (ED). Prompt and accurate risk stratification to identify those patients with NSTE chest pain who are at highest risk for adverse events is essential, however, to optimal management. Although validated and used frequently in patients already enrolled in acute coronary syndrome trials, the Thrombolysis in Myocardial Infarction (TIMI) risk score never has been examined for its value in risk stratification in an all‐comers, non–trial‐based ED chest pain population. Methods: An analysis of an ED‐based prospective observational cohort study was conducted in 3,929 adult patients presenting with chest pain syndrome and warranting evaluation with an electrocardiogram. These patients had TIMI risk scores determined at ED presentation. The main outcome was the composite of death, acute myocardial infarction (MI), and revascularization within 30 days. Results: The TIMI risk score at ED presentation successfully risk‐stratified this unselected cohort of chest pain patients with respect to 30‐day adverse outcome, with a range from 2.1%, with a score of 0, to 100%, with a score of 7. The highest correlation of an individual TIMI risk indicator to adverse outcome was for elevated cardiac biomarker at admission. Overall, the score had similar performance characteristics to that seen when applied to other databases of patients enrolled in clinical trials and registries using a 14‐day end point. Conclusions: The TIMI risk score may be a useful tool for risk stratification of ED patients with chest pain syndrome.     

Physician Variability in History Taking When Evaluating Patients Presenting with Chest Pain in the Emergency Department

Objectives: The goal of this study was to examine how physicians in the emergency department ask questions of patients presenting with chest pain and whether this varies by patient demographics.
Methods: This was a cross-sectional study with convenience sampling. A survey was administered to adult emergency department patients presenting with chest pain after emergency physicians obtained the history and performed the physical examination. No identifying data were collected from the patients. In addition to demographics, patients were asked whether or not their physician asked them about factors related to coronary syndrome and myocardial infarction etiology.
Results: A total of 308 of 332 patients (93%) participated. Patients had a mean age of 52 years, 54% were male, and 85% spoke English; classification by race was 31% African American, 28% white, 19% Hispanic, and 13% other. History taking did not differ by gender. Patients who reported being asked about the following were statistically significantly younger than those who reported not being asked: family history, other medical problems, smoking, cocaine use, and alcohol use. Nonwhite patients reported being asked about the following more frequently than white patients: smoking (94% vs. 84%), alcohol use (81% vs. 70%), and cocaine use (64% vs. 42%). In multivariate logistic regression controlling for age, nonwhite patients were more likely than white patients to be asked about smoking (odds ratio [OR], 2.79; 95% confidence interval [CI] = 1.26 to 6.19), cocaine use (OR, 2.49; 95% CI = 1.50 to 4.12), and alcohol use (OR, 1.77; 95% CI = 1.0 to 3.09).
Conclusions: The variability in questions about behavioral factors associated with chest pain etiology as reported by patients may indicate a possible cultural bias by physicians. Differences in risk identification may lead to differences in treatment decisions.     

Immediate Stress Echocardiography for Low-Risk Chest Pain Patients in the Emergency Department: A Prospective Observational Cohort Study

Background

Evaluation and disposition of low-risk chest pain (CP) patients in the emergency department (ED) is time consuming and expensive. Low-risk CP often results in hospital admission to rule out myocardial infarction, which leads to additional costs and delays.

Heart Rate Variability Analysis in Patients Who Have Bradycardia Presenting to the Emergency Department with Chest Pain

Background

Heart rate variability (HRV) is a noninvasive method to measure the function of the autonomic nervous system. It has been used to risk stratify patients with undifferentiated chest pain in the emergency department (ED). However, bradycardia can have a modifying effect on HRV.

Ranolazine and Microvascular Angina by PET in the Emergency Department: Results From a Pilot Randomized Controlled Trial

Purpose

Coronary microvascular dysfunction (CMD) is a common but underdiagnosed cause of chest pain. Literature is scant regarding effective treatments. We explored the effect of ranolazine on coronary flow reserve (CFR) among symptomatic patients with CMD.

Impact of Technetium-99m Sestamibi Imaging on the Emergency Department Management and Costs in the Evaluation of Low-risk Chest Pain

OBJECTIVES: To assess the impact of rest sestamibi scanning on emergency physicians' (EPs') diagnostic certainty and decision making (as assessed by the hypothetical disposition of patients) for 69 consenting stable patients with suspected acute cardiac ischemia and nondiagnostic electrocardiograms. The resultant impact on costs was examined as a secondary outcome. METHODS: Patients with suspected acute cardiac ischemia were injected with 25 mCi of sestamibi within two hours of active pain in one of three emergency department study sites. The probability of acute myocardial infarction (AMI) and unstable angina (UA), and hypothetical disposition decisions were recorded immediately before and after physicians were notified of scan results. Changes in disposition were classified as optimal or suboptimal. For the cost determinations, a cost-based decision support program was used. RESULTS: For the subgroup found to be free of acute cardiac events (ACEs) (n = 62), the EPs' post-sestamibi scan probabilities for AMI decreased by 11% and UA by 18% (p < 0.001 for both conditions). In seven patients with ACEs, the post-scan probabilities of AMI and UA increased, but neither was statistically significant. Scan results led to hypothetical disposition changes in 29 patients (42%), of which 27 (93%) were optimal (nine patients were reassigned to a lower level of care, two to a higher level, and 16 additional patients to "discharge-home" status). The strategy of scanning all patients who were low to moderate risk for acute cardiac ischemia would result in an increase of direct costs of care of $222 per patient evaluated, due to added cost of sestamibi scanning. CONCLUSIONS: Sestamibi scanning results appropriately affected the EPs' estimates of the probability of AMI and UA and improved disposition decisions. Scanning all low-risk patients would likely be associated with increased costs at this medical center.     

Emergency Department Chest Pain Patients With or Without Ongoing Pain: Characteristics,Outcome, and Diagnostic Value of the Electrocardiogram

BackgroundIn emergency department (ED) chest pain patients, it is believed that the diagnostic accuracy of the electrocardiogram (ECG) for acute coronary syndrome (ACS) is higher during ongoing than abated chest pain.ObjectivesWe compared patient characteristics and the diagnostic performance of the ECG in ED patients presenting with ongoing, vs. abated, chest pain.MethodsIn total, 1132 unselected ED chest pain patients were analyzed. The patient characteristics and diagnostic accuracy for index visit ACS of the emergency physicians’ interpretation of the ECG was compared in patients with and without ongoing chest pain. Logistic regression analysis was performed to control for possible confounders.ResultsPatients with abated chest pain (n = 508) were older, had more comorbidities, and had double the risk of index visit ACS (15%) and major adverse cardiac events (MACE) at 30 days (15.6%) compared with patients with ongoing pain (n = 631; ACS 7.3%, 30-day MACE 7.4%). Sensitivity of the ECG for ACS was 24% in patients with ongoing pain and 35% in those without, specificity was 97% in both groups, negative predictive value was 94% and 89%, respectively, and positive likelihood ratio 10.6 and 7.8, respectively. When the diagnostic performance was controlled for confounders, there was no significant difference between the groups.ConclusionOur results indicate that ED chest pain patients with ongoing pain at arrival are younger, healthier, and have less ACS and 30-day MACE than patients with abated pain, but that there is no difference in the diagnostic accuracy of the ECG for ACS between the two groups.     

Prospective Validation of a Modified Thrombolysis In Myocardial Infarction Risk Score in Emergency Department Patients With Chest Pain and Possible Acute Coronary Syndrome

Objectives: This study attempted to prospectively validate a modified Thrombolysis In Myocardial Infarction (TIMI) risk score that classifies patients with either ST‐segment deviation or cardiac troponin elevation as high risk. The objectives were to determine the ability of the modified score to risk‐stratify emergency department (ED) patients with chest pain and to identify patients safe for early discharge. Methods: This was a prospective cohort study in an urban academic ED over a 9‐month period. Patients over 24 years of age with a primary complaint of chest pain were enrolled. On‐duty physicians completed standardized data collection forms prior to diagnostic testing. Cardiac troponin T‐values of >99th percentile (≥0.01 ng/mL) were considered elevated. The primary outcome was acute myocardial infarction (AMI), revascularization, or death within 30 days. The overall diagnostic accuracy of the risk scores was compared by generating receiver operating characteristic (ROC) curves and comparing the area under the curve. The performance of the risk scores at potential decision thresholds was assessed by calculating the sensitivity and specificity at each potential cut‐point. Results: The study enrolled 1,017 patients with the following characteristics: mean (±SD) age 59.3 (±13.8) years, 60.6% male, 17.9% with a history of diabetes, and 22.4% with a history of myocardial infarction. A total of 117 (11.5%) experienced a cardiac event within 30 days (6.6% AMI, 8.9% revascularization, 0.2% death of cardiac or unknown cause). The modified TIMI risk score outperformed the original with regard to overall diagnostic accuracy (area under the ROC curve = 0.83 vs. 0.79; p = 0.030; absolute difference 0.037; 95% confidence interval [CI] = 0.004 to 0.071). The specificity of the modified score was lower at all cut‐points of >0. Sensitivity and specificity at potential decision thresholds were: >0 = sensitivity 96.6%, specificity 23.7%; >1 = sensitivity 91.5%, specificity 54.2%; and >2 = sensitivity 80.3%, specificity 73.4%. The lowest cut‐point (TIMI/modified TIMI >0) was the only cut‐point to predict cardiac events with sufficient sensitivity to consider early discharge. The sensitivity and specificity of the modified and original TIMI risk scores at this cut‐point were identical. Conclusions: The modified TIMI risk score outperformed the original with regard to overall diagnostic accuracy. However, it had lower specificity at all cut‐points of >0, suggesting suboptimal risk stratification in high‐risk patients. It also lacked sufficient sensitivity and specificity to safely guide patient disposition. Both scores are insufficiently sensitive and specific to recommend as the sole means of determining disposition in ED chest pain patients. ACADEMIC EMERGENCY MEDICINE 2010; 17:368–375 © 2010 by the Society for Academic Emergency Medicine     

Assessment of Risk Tolerance for Adverse Events in Emergency Department Chest Pain Patients: A Pilot Study

Background: Emergency physicians commonly encounter low-probability/high-morbidity decisions, and chest pain is a prime example. Negative outcomes are improbable but feared, resulting in substantially more patients admitted for chest pain than have important disease. The literature gives little guidance on patient preferences for decision-making when the negative outcomes are unlikely but potentially severe. Objectives: The objective of this pilot study was to assess the tolerance of Emergency Department (ED) patients with chest pain for adverse events occurring within 2 weeks of the episode. Method: We recruited a convenience sample of patients with a chief complaint of chest pain from the ED of an urban tertiary-care referral center. Each subject was interviewed to determine demographic information, perceived health status, insurance status, and tolerance for adverse events related to chest pain. Adverse events were defined loosely but were suggested to be heart attack, the need for emergency cardiac surgery, or death. The risk tolerance question was framed by describing a specific numeric risk and determining at what risk the patient switched from desiring hospital admission to desiring discharge; we termed this the decision threshold. Results: Sixty-eight (68) subjects were included. Fifty-four percent of subjects were male, 60% were African-American, and 35% were white; 40% of the subjects classified themselves as being of average health. Of the 31 subjects who had prior heart trouble, 48% (n = 15) stated they had a prior heart attack and 19% (n = 6) an irregular heartbeat. The median decision threshold, or the acceptable personal risk of an adverse event for a person to forego admission to hospital, was 6.5% (interquartile range 0.5–22.9%). The mode was 0.5%, and 44% (30/68) of subjects had a decision threshold of 2% or less. There was no obvious pattern for most of these explanatory variables, though there was a suggestion that race may affect patients' risk tolerance. Conclusions: There is substantial variation in patients' reported tolerance for adverse events from ED chest pain. Further investigation of this phenomenon may lead to better decision-making.     

Prognosticating Clinical Prediction Scores Without Clinical Gestalt for Patients With Chest Pain in the Emergency Department

Background

Assessment of patients with chest pain is a regular challenge in the emergency department (ED). Recent guidelines recommended quantitative assessment of ischemic risk by means of risk scores.

Evaluation of a Bedside Whole-blood Rapid Troponin T Assay in the Emergency Department

Objective : To evaluate the performance of a new bedside whole-blood rapid assay for cardiac troponin T (cTnT) in patients presenting to the ED with symptoms consistent with acute coronary ischemia. Methods : A prospective, observational trial was performed in 8 participating medical centers. Serial blood samples were obtained on presentation to the ED and 3 and 6 hours later. The cTnT whole-blood rapid assays were performed immediately at the site. Treating physicians and patients were blinded to the results of the rapid assays. Serum samples were analyzed at the core laboratory for serum cTnT, creatine kinase (CK)-MB, and myoglobin. The sensitivity of the rapid assay for detecting acute myocardial infarction (AMI) was compared with the sensitivities of serum cTnT, CK-MB, and myoglobin assays. Results : Of 721 patients, 102 were diagnosed as having AMI. The median elapsed time from symptom onset to ED arrival was 3 hours. The sensitivities of the rapid assay for detecting AMI were 19.6%, 59.0%, and 69.7% at 0, 3, and 6 hours, respectively. The sensitivities of the serum cTnT assay (p-values for comparison with the rapid assay for cTnT) were 25.0% (p = 0.18), 69.6% (p = 0.04), and 79.8% (p = 0.02) at 0, 3, and 6 hours, respectively. The CK-MB and myoglobin sensitivities were 21.9%, 64.5%, and 81.0%; and 43.8%, 77.4%, and 71.4%, respectively. There were 7 patients with AMI who had negative rapid assay readings and positive serum cTnT levels; 4 of these patients were enrolled at the same site. Twenty patients not diagnosed as having AMI had at least one positive rapid assay. Fourteen of these 20 patients had a diagnosis of clinically relevant cardiac disease. Conclusions : The sensitivity of this whole-blood rapid cTnT assay for detecting AMI is comparable to that of current serum assays and offers the advantage of providing rapid bedside results. Discrepancies between serum and whole-blood assays for cTnT noted in this study may indicate the need for further education for the test reader prior to patient use.     

Impact of the HEART Pathway on Admission Rates for Emergency Department Patients with Chest Pain: An External Clinical Validation Study

Background

Chest pain is a common emergency department (ED) chief complaint. Safe discharge mechanisms for low-risk chest pain patients would be useful.

Impact of Point-of-care Testing in the Emergency Department Evaluation and Treatment of Patients with Suspected Acute Coronary Syndromes

Objectives:  To assess the impact of point-of-care testing (POCT) for troponin I (cTnI) measurement on the time to anti-ischemic therapy (TAIT) for patients with suspected non–ST-segment elevation acute coronary syndrome (NSTE-ACS) presenting to the emergency department (ED).
Methods:  This was an open-label, randomized, single-center trial conducted in a university-affiliated hospital. cTnI measurement of patients with suspicion of NSTE-ACS coming to the ED was randomly allocated to POCT or central hospital laboratory testing (CHLT). The authors compared patients' baseline characteristics, time to anti-ischemic therapy, and medical outcomes between the randomized groups, in all study participants and in high-risk NSTE-ACS (cTnI level ≥ 0.10 μg/mL), and in those with low suspicion ACS (no chest pain and no ST deviation).
Results:  Of the 860 patients enrolled, 113 were high-risk NSTE-ACS patients, including 53 (46.9%) allocated to POCT and 60 (53.1%) to CHLT. POCT was associated with decreased time to anti-ischemic therapy of about three-quarters of an hour, which was due to a shorter time to physician notification of cTnI level, in both all and subgroup participants. In contrast, neither ED length of stay nor medical outcomes differed between study groups.
Conclusions:  Point-of-care testing for cTnI measurement might be clinically relevant for ED patients with a suspicion of NSTE-ACS, particularly for high-risk patients with a low suspicion of ACS.