American College of Emergency Physicians information paper: chest pain units in emergency departments--a report from the Short-Term Observation Services Section

Sex differences of patients with acute chest pain evaluated through a chest pain unit

BACKGROUND

Although sex disparities between patients with acute myocardial infarction are well known, the data regarding sex differences among symptomatic patients with acute chest pain (ACP) are limited.

METHODS

We retrospectively evaluated the records of 1000 consecutive patients with ACP and hospitalized in a tertiary medical center chest pain unit (CPU). Patients were divided according to sex. The primary outcome was defined as a composite end point of readmission because of chest pain, incidence of acute coronary syndrome, revascularization, and death at 90 days and 1 year.

RESULTS

Overall, 673 men and 327 women were included in the current analysis. There was no difference in regard to sex for patients who underwent noninvasive evaluation, (87.8 vs. 87.3%, P = 0.85, for female vs. male, respectively). Among patients who underwent coronary computed tomography angiography, women were less likely to have significant coronary artery disease (CAD) (4.2 vs. 11.3%, P = 0.005). Similarly, women had fewer significant findings (4.4 vs. 7.6%, P = 0.007) on myocardial perfusion imaging. Consequently, fewer women underwent angiography (8 vs. 14%, P = 0.006) and revascularization (2.8 vs. 7.3%, P = 0.004). During follow-up, sex was not associated with the development of the primary composite outcome [odds ratio (OR) 0.91, 95% confidence interval (CI) 0.39-2.09, P-value = 0.82 and OR 1.16, 95% CI 0.65-2.06, P-value = 0.59 for 90-day and 1-year follow-up, respectively].

CONCLUSION

Evaluation of patients through a CPU enables comparable noninvasive evaluation, appropriate utilization of invasive assessment with similar outcomes during the short and intermediate follow-up period regardless of patients' sex.

German chest pain unit registry: data review after the first decade of certification

In 2008, the German Cardiac Society (GCS) introduced a certification program for specialized chest pain units (CPUs). In order to benchmark the performance of the certified CPUs, a nationwide German CPU registry was established. Since then, data for more than 34,000 patients have been included. The concept of certified CPUs in Germany has been widely accepted and its success is underlined by its recent inclusion in national and international guidelines. As of December 2019, 286 CPUs have been successfully certified or recertified by the GCS. This review focuses on the data retrieved from the CPU registry during the first decade of certification. As demonstrated by 16 manuscripts stemming from the registry, certified German CPUs demonstrate high quality of care in acute coronary syndrome and beyond. It is also noted that the German CPU registry allowed for further analysis of the gap in guideline adherence. With the current update of the CPU certification criteria, central data collection as a best-practice criterion will be abandoned, and after some productive years the registry has temporarily been stopped.

Chest Pain Centers: A Comparison of Accreditation Programs in Germany and the United States

OBJECTIVE

The implementation of chest pain centers (CPC)/units (CPU) has been shown to improve emergency care in patients with suspected cardiac ischemia.

METHODS

In an effort to provide a systematic and specific standard of care for patients with acute chest pain, the Society of Cardiovascular Patient Care (SCPC) as well as the German Cardiac Society (GCS) introduced criteria for the accreditation of specialized units.

RESULTS

To date, 825 CPCs in the United States and 194 CPUs in Germany have been successfully certified by the SCPC or GCS, respectively. Even though there are differences in the accreditation processes, the goals are quite similar, focusing on enhanced operational efficiencies in the care of the acute coronary syndrome patients, reduced time delays, improved diagnostic and therapeutic strategies using adapted standard operating procedures, and increased medical as well as community awareness by the implementation of nationwide standardized concepts. In addition to national efforts, both societies have launched international initiatives, accrediting CPCs/CPU in the Middle East and China (SCPC) and Switzerland (GCS).

CONCLUSION

Enhanced collaboration among international bodies interested in promoting high quality care might extend the opportunity for accreditation of facilities that treat cardiovascular patients, with national programs designed to meet local needs and local healthcare system requirements.

Acute coronary syndromes: We must improve diagnostic efficiency in the emergency department

Chaque année, 100 000 Canadiens sont hospitalisés pour des syndromes coronariens aigus (SCA) (infarctus aigu du myocarde et angine instable); un aussi grand nombre de patients sont hospitalisés pour que soit finalement «écarté» le diagnostic de SCA. Le diagnostic de SCA doit être rapide et exact afin de réduire le taux de mortalité et de prévenir la progression de l’angine instable vers un infarctus du myocarde. En même temps, on doit limiter les coûts inutiles liés au traitement de ces patients. Malheureusement, aucune épreuve ou stratégie particulières ne permettent d’identifier de façon définitive tous les patients atteints de SCA. Les unités de douleur thoracique à l’urgence, de plus en plus populaires, permettent de réduire le nombre d’hospitalisations aux unités de soins critiques en appliquant des protocoles diagnostiques intensifs au département d’urgence. Mais ces unités diminuent-elles les coûts ou ne font-elles qu’augmenter la proportion de patients soumis à des épreuves? Plutôt que de soumettre tous les patients au même processus diagnostique, les urgentologues devraient classer les patients selon leur risque parmi l’une des trois catégories suivantes : ceux dont la probabilité de SCA est faible qui nécessitent un minimum d’épreuves à l’urgence; ceux qui présentent des signes évidents de SCA et qui doivent être hospitalisés; et ceux dont la probabilité de SCA est intermédiaire et qui doivent subir différentes épreuves.

A comparison of coronary CTA and stress testing using high-efficiency SPECT MPI for the evaluation of chest pain in the emergency department

BACKGROUND

Recent studies have compared CTA to stress testing and MPI using older Na-I SPECT cameras and traditional rest-stress protocols, but are limited by often using optimized CTA protocols but suboptimal MPI methodology. We compared CTA to stress testing with modern SPECT MPI using high-efficiency CZT cameras and stress-first protocols in an ED population.

METHODS

In a retrospective, non-randomized study, all patients who underwent CTA or stress testing (ETT or Tc-99m sestamibi SPECT MPI) as part of their ED assessment in 2010-2011 driven by ED attending preference and equipment availability were evaluated for their disposition from the ED (admission vs discharge, length of time to disposition), subsequent visits to the ED and diagnostic testing (within 3 months), and radiation exposure. CTA was performed using a 64-slice scanner (GE Lightspeed VCT) and MPI was performed using a CZT SPECT camera (GE Discovery 530c). Data were obtained from prospectively acquired electronic medical records and effective doses were calculated from published conversion factors. A propensity-matched analysis was also used to compare outcomes in the two groups.

RESULTS

A total of 1,458 patients underwent testing in the ED with 192 CTAs and 1,266 stress tests (327 ETTs and 939 MPIs). The CTA patients were a lower-risk cohort based on age, risk factors, and known heart disease. A statistically similar proportion of patients was discharged directly from the ED in the stress testing group (82% vs 73%, P = .27), but their time to disposition was longer (11.0 ± 5 vs 20.5 ± 7 hours, P < .0001). There was no significant difference in cardiac return visits to the ED (5.7% CTA vs 4.3% stress testing, P = .50), but more patients had follow-up studies in the CTA cohort compared to stress testing (14% vs 7%, P = .001). The mean effective dose of 12.6 ± 8.6 mSv for the CTA group was higher (P < .0001) than 5.0 ± 4.1 mSv for the stress testing group (ETT and MPI). A propensity score-matched cohort showed similar results to the entire cohort.

CONCLUSIONS

Stress testing with ETT, high-efficiency SPECT MPI, and stress-only protocols had a significantly lower patient radiation dose and less follow-up diagnostic testing than CTA with similar cardiac return visits. CTA had a shorter time to disposition, but there was a trend toward more revascularization than with stress testing.

Key operational characteristics in emergency department observation units: a comparative study between sites in the United States and Asia

Background

To improve efficiency, emergency departments (EDs) use dedicated observation units (OUs) to manage patients who are unable to be discharged home, yet do not clearly require inpatient hospitalization. However, operational metrics and their ideal targets have not been created for this setting and patient population. Variation in these metrics across different countries has not previously been reported. This study aims to define and compare key operational characteristics between three ED OUs in the United States (US) and three ED OUs in Asia.

Methods

This is a descriptive study of six tertiary-care hospitals, all of which are level 1 trauma centers and have OUs managed by ED staff. We collected data via various methods, including a standardized survey, direct observation, and interviews with unit leadership, and compared these data across continents.

Results

We define multiple key operational characteristics to compare between sites, including OU length of stay (LOS), OU discharge rate, and bed turnover rate. OU LOS in the US and Asian sites averaged 12.9 hours (95% CI, 8.3 to 17.5) and 20.5 hours (95% CI, -49.4 to 90.4), respectively (P = 0.39). OU discharge rates in the US and Asia averaged 84.3% (95% CI, 81.5 to 87.2) and 88.7% (95% CI, 81.5 to 95.8), respectively (P = 0.11), and the bed turnover rates in the US and Asian sites averaged 1.6 patients/bed/day (95% CI, -0.1 to 3.3) and 0.9 patient/bed/day (95% CI, -0.6 to 2.4), respectively (P = 0.27).

Conclusions

Prior research has shown that the OU is a resource that can mitigate many of problems in the ED and hospital, while simultaneously improving patient care and satisfaction. We describe key operational characteristics that are relevant to all OUs, regardless of geography or healthcare system to monitor and maximize efficiency. Although measures of LOS and bed turnover varied widely between US and Asian sites, we did not find a statistically significant difference. Use of these metrics may enable hospitals to establish or revise an ED OU and reduce OU LOS, increase bed turnover, and discharge rates while simultaneously improving patient satisfaction and quality of care.

Emergency department observation units: A clinical and financial benefit for hospitals

INTRODUCTION

There are nearly 120 million visits to emergency departments each year, one for every three people in the United States. Fifty percent of all hospital admissions come from this group, a marked change from the mid-1990s when the emergency department was a source of only a third of admissions. As the population increases and ages, the growth rate for emergency department visits and the resulting admissions will exceed historical trends creating a surge in demand for inpatient beds.

BACKGROUND

Current health care reform efforts are highlighting deficiencies in access, cost, and quality of care in the United States. The need for more inpatient capacity brings attention to short-stay admissions and whether they are necessary. Emergency department observation units provide a suitable alternate venue for many such patients at lower cost without adversely affecting access or quality.

METHODS

This article serves as a literature synthesis in support of observation units, with special emphasis on the clinical and financial aspects of their use. The observation medicine literature was reviewed using PubMed, and selected sources were used to summarize the current state of practice. In addition, the authors introduce a novel conceptual framework around measures of observation unit efficiency.

FINDINGS AND PRACTICE IMPLICATIONS

Observation units provide high-quality and efficient care to patients with common complaints seen in the emergency department. More frequent use of observation can increase patient safety and satisfaction while decreasing unnecessary inpatient admissions and improving fiscal performance for both emergency departments and the hospitals in which they operate. For institutions with the volume to justify the fixed costs of operating an observation unit, the dominant strategy for all stakeholders is to create one.

Short- and long-term cardiac events in patients with chest pain with or without known existing coronary disease presenting normal electrocardiogram

AIM

The aim of this study is to evaluate incidence of adverse cardiac events in patients with chest pain with or without known existing coronary disease presenting normal electrocardiogram (ECG) and initial troponin.

METHODS

Prospective, nonrandomized study enrolled low-risk patients with normal ECG and troponin on admission who underwent observation and/or stress testing by unstandardized clinical judgment. Patients who experienced recurrent angina or positive ECGs or positive troponins during observation or patients with positive stress testing were admitted; otherwise, they were discharged.

END POINT

The end points are cardiac events at short- and long-term follow-up including cardiovascular death, myocardial infarction, unstable angina, and revascularization.

RESULTS

Of 5656 patients considered, 1732 with ischemic ECG were initially admitted and, therefore, excluded from the analysis; 2860 with pleuritic chest pain and normal ECG were discharged; 1064 with visceral chest pain and normal ECG were enrolled. Patients with known coronary disease (45%) were older and likely presented known vascular disease. Patients with known vascular disease, older age, female sex, diabetes mellitus, and lower chest pain score were likely managed with observation. In patients with known coronary disease as compared with patients without, overall cardiac events account for 35% vs 14%, respectively (P < .001), as follows: in-hospital, 23% vs 10%, (P < .001); 1 month, 4% vs 2% (P = .133); and 9.9 ± 4.9 months, 8% vs 2%, respectively (P < .001).

CONCLUSIONS

One-third of patients with chest pain with known coronary disease, negative ECG, and biomarkers were subsequently found to have adverse cardiac events. The value of this research for an emergency medicine audience could be extended to all clinicians and general practitioners beyond cardiologists.

Use of observation care in US emergency departments, 2001 to 2008

BACKGROUND

Observation care is a core component of emergency care delivery, yet, the prevalence of emergency department (ED) observation units (OUs) and use of observation care after ED visits is unknown. Our objective was to describe the 1) prevalence of OUs in United States (US) hospitals, 2) clinical conditions most frequently evaluated with observation, and 3) patient and hospital characteristics associated with use of observation.

METHODS

Retrospective analysis of the proportion of hospitals with dedicated OUs and patient disposition after ED visit (discharge, inpatient admission or observation evaluation) using the National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2001 to 2008. NHAMCS is an annual, national probability sample of ED visits to US hospitals conducted by the Center for Disease Control and Prevention. Logistic regression was used to assess hospital-level predictors of OU presence and polytomous logistic regression was used for patient-level predictors of visit disposition, each adjusted for multi-level sampling data. OU analysis was limited to 2007-2008.

RESULTS

In 2007-2008, 34.1% of all EDs had a dedicated OU, of which 56.1% were under ED administrative control (EDOU). Between 2001 and 2008, ED visits resulting in a disposition to observation increased from 642,000 (0.60% of ED visits) to 2,318,000 (1.87%, p<.05). Chest pain was the most common reason for ED visit resulting in observation and the most common observation discharge diagnosis (19.1% and 17.1% of observation evaluations, respectively). In hospital-level adjusted analysis, hospital ownership status (non-profit or government), non-teaching status, and longer ED length of visit (>3.6 h) were predictive of OU presence. After patient-level adjustment, EDOU presence was associated with increased disposition to observation (OR 2.19).

CONCLUSIONS

One-third of US hospitals have dedicated OUs and observation care is increasingly used for a range of clinical conditions. Further research is warranted to understand the quality, cost and efficiency of observation care.

Testing of low-risk patients presenting to the emergency department with chest pain: a scientific statement from the American Heart Association

The management of low-risk patients presenting to emergency departments is a common and challenging clinical problem entailing 8 million emergency department visits annually. Although a majority of these patients do not have a life-threatening condition, the clinician must distinguish between those who require urgent treatment of a serious problem and those with more benign entities who do not require admission. Inadvertent discharge of patients with acute coronary syndrome from the emergency department is associated with increased mortality and liability, whereas inappropriate admission of patients without serious disease is neither indicated nor cost-effective. Clinical judgment and basic clinical tools (history, physical examination, and electrocardiogram) remain primary in meeting this challenge and affording early identification of low-risk patients with chest pain. Additionally, established and newer diagnostic methods have extended clinicians' diagnostic capacity in this setting. Low-risk patients presenting with chest pain are increasingly managed in chest pain units in which accelerated diagnostic protocols are performed, comprising serial electrocardiograms and cardiac injury markers to exclude acute coronary syndrome. Patients with negative findings usually complete the accelerated diagnostic protocol with a confirmatory test to exclude ischemia. This is typically an exercise treadmill test or a cardiac imaging study if the exercise treadmill test is not applicable. Rest myocardial perfusion imaging has assumed an important role in this setting. Computed tomography coronary angiography has also shown promise in this setting. A negative accelerated diagnostic protocol evaluation allows discharge, whereas patients with positive findings are admitted. This approach has been found to be safe, accurate, and cost-effective in low-risk patients presenting with chest pain.

Emergency department and office-based evaluation of patients with chest pain

The management of patients with chest pain is a common and challenging clinical problem. Although most of these patients do not have a life-threatening condition, the clinician must distinguish between those who require urgent management of a serious problem such as acute coronary syndrome (ACS) and those with more benign entities who do not require admission. Although clinical judgment continues to be paramount in meeting this challenge, new diagnostic modalities have been developed to assist in risk stratification. These include markers of cardiac injury, risk scores, early stress testing, and noninvasive imaging of the heart. The basic clinical tools of history, physical examination, and electrocardiography are currently widely acknowledged to allow early identification of low-risk patients who have less than 5% probability of ACS. These patients are usually initially managed in the emergency department and transitioned to further outpatient evaluation or chest pain units. Multiple imaging strategies have been investigated to accelerate diagnosis and to provide further risk stratification of patients with no initial evidence of ACS. These include rest myocardial perfusion imaging, rest echocardiography, computed tomographic coronary angiography, and cardiac magnetic resonance imaging. All have very high negative predictive values for excluding ACS and have been successful in reducing unnecessary admissions for patients at low to intermediate risk of ACS. As patients with acute chest pain transition from the evaluation in the emergency department to other outpatient settings, it is important that all clinicians involved in the care of these patients understand the tools used for assessment and risk stratification.

Evaluation of the chest pain patient: survey of current practice patterns

The objective of this study was to measure the prevalence of chest pain centers, and describe the associated protocols most commonly used to rapidly risk-stratify patients in these units. This study is a survey conducted from May to July 2003 via direct mail. A questionnaire was mailed to 4653 hospitals in the United States. A total of 462 questionnaires were returned, representing a return rate of approximately 10%. This survey revealed that approximately 64% of all hospitals have a protocol for the evaluations of patients who present with chest pain, and 38% of all hospitals reported a designated area for the evaluation of these patients. The majority of hospitals responding to this survey have a protocol for the evaluation of patients presenting with chest pain, however, the presence of a chest pain unit exists in only 38% of all responding institutions.

Chest pain center accreditation is associated with better performance of centers for Medicare and Medicaid services core measures for acute myocardial infarction

The aim of this study was determine whether hospitals accredited by the Society of Chest Pain Centers hospitals (accredited chest pain centers [ACPCs]) are associated with better performance regarding Centers for Medicare and Medicaid Services core measures for acute myocardial infarction (AMI) than nonaccredited hospitals. The study was a retrospective, observational cohort study of hospitals reporting Centers for Medicare and Medicaid Services core measures for AMI from January 1, 2005, to December 31, 2005, on the basis of the presence or absence of Society of Chest Pain Centers accreditation. Data were obtained from the Web sites of the Centers for Medicare and Medicaid Services (Hospital Compare), Society of Chest Pain Centers listings, and the American Hospital Directory. Groups were compared in terms of demographics and mean percentage compliance with all 8 AMI core measures. Student's t test, chi-square analysis, and logistic regression were used to analyze bivariate relations. Multivariate logistic regression models used a propensity-score adjustment factor. Of the 4,197 hospitals that reported core measures for AMI, 178 (4%) were accredited and 4,019 (96%) were not. ACPCs had been accredited for an average of 12 months and were larger (378 vs 204 beds), more often teaching hospitals (52% vs 30%), and more often urban (95% vs 69%) (all p <0.0001). There were 395,250 patients with AMIs, of whom 55,418 (14%) presented to ACPCs and 339,832 (86%) presented to nonaccredited hospitals. There was significantly greater compliance with all 8 AMI core measures at ACPCs (p <0.0001), except for lytic therapy <30 minutes after arrival (p = 0.04), for which unadjusted performance was the same. In conclusion, ACPCs were associated with better compliance with Centers for Medicare and Medicaid Services core measures and saw a greater proportion of patients with AMIs.

Are emergency chest pain patients ready to quit smoking?

This study examined predictors of readiness to quit smoking among emergency chest pain patients admitted to the observation unit (OU) to rule out myocardial infarction. While in the OU, patients (n=543) completed surveys assessing smoking history, nicotine dependence, readiness to quit, and other relevant variables. Participants smoked an average of 18.8 (SD=12.6) cigarettes per day. More than half (58%) had made at least 1 serious quit attempt > or = 24 hours) in the past year. Most had never used nicotine replacement medications. Nicotine dependence, perceived risk from smoking, and patient perceptions that smoking might be related to their chest pain were significantly associated with readiness to quit (P<.05). Results indicate that a significant proportion of OU patients think they are at relatively low risk from smoking and, although motivated to quit, are not using medications appropriately to assist quit attempts. There is a need for intervention and education with this population of patients.

The impact of alcohol, tobacco, and other drug use and abuse in the emergency department

Alcohol, tobacco, and other drug use is a significant societal problem. Individuals who use these substances are frequently seen in emergency departments at rates disproportionately greater than their population prevalence. This article highlights the impact of these drugs on patients and on emergency departments, including common presenting problems of individuals on these substances. Also discussed is how to help and to refer individuals with substance abuse problems through brief motivational interventions.

Exercise testing in chest pain units: rationale, implementation, and results

Chest pain units are now established centers for assessment of low-risk patients presenting to the emergency department with symptoms suggestive of acute coronary syndrome. Accelerated diagnostic protocols, of which treadmill testing is a key component, have been developed within these units for efficient evaluation of these patients. Studies of the last decade have established the utility of early exercise testing,which has been safe, accurate, and cost-effective in this setting. Specific diagnostic protocols vary, but most require 6 to 12 hours of observation by serial electrocardiography and cardiac injury markers to exclude infarction and high-risk unstable angina before proceeding to exercise testing. However, in the chest pain unit at UC Davis Medical Center,the approach includes "immediate" treadmill testing without a traditional process to rule out myocardial infarction. Extensive experience has validated this approach in a large, heterogeneous population. The optimal strategy for evaluating low-risk patients presenting to the emergency department with chest pain will continue to evolve based on current research and the development of new methods.

A clinical prediction rule for early discharge of patients with chest pain

STUDY OBJECTIVE

Current risk stratification tools do not identify very-low-risk patients who can be safely discharged without prolonged emergency department (ED) observation, expensive rule-out protocols, or provocative testing. We seek to develop a clinical prediction rule applicable within 2 hours of ED arrival that would miss fewer than 2% of acute coronary syndrome patients and allow discharge within 2 to 3 hours for at least 30% of patients without acute coronary syndrome.

METHODS

This prospective, cohort study enrolled consenting eligible subjects at least 25 years old at a single site. At 30 days, investigators assigned a diagnosis of acute coronary syndrome or no acute coronary syndrome according to predefined explicit definitions. A recursive partitioning model included risk factors, pain characteristics, physical and ECG findings, and cardiac marker results.

RESULTS

Of 769 patients studied, 77 (10.0%) had acute myocardial infarction and 88 (11.4%) definite unstable angina. We derived a clinical prediction rule that was 98.8% sensitive and 32.5% specific. Patients have very low risk of acute coronary syndrome if they have a normal initial ECG, no previous ischemic chest pain, and age younger than 40 years. In addition, patients at least 40 years old and with a normal ECG result, no previous ischemic chest pain, and low-risk pain characteristics have very low risk if they have an initial creatine kinase-MB (CK-MB) less than 3.0 microg/L or an initial CK-MB greater than or equal to 3.0 microg/L but no ECG or serum-marker increase at 2 hours.

CONCLUSION

The Vancouver Chest Pain Rule for early discharge defines a group of patients who can be safely discharged after a brief evaluation in the ED. Prospective validation is needed.

Acute coronary syndrome national statistics: challenges in definitions

BACKGROUND

Increasing convergence in the management of acute myocardial infarction (AMI) and unstable angina (UA) has led some to consider whether these 2 diagnoses should be consolidated into acute coronary syndrome (ACS) for the purpose of coronary heart disease surveillance.

METHODS

We used the 1988-2001 Nationwide Inpatient Sample, which has demographic and diagnosis data on 6 to 7 million discharges per year from a sample of US nonfederal hospitals. We identified discharges with a first- or all-listed diagnosis of AMI ( International Classification of Diseases, Ninth Revision, Clinical Modification 410) or UA (International Classification of Diseases, Ninth Revision, Clinical Modification 411) and defined ACS-first as a primary diagnosis of either condition and all-listed ACS as codes 410 or 411 among any diagnoses. Sampling weights were applied to produce yearly national discharge estimates; annual population estimates were used to calculate yearly hospital discharge rates; rates were then adjusted to the 2000 standard population.

RESULTS

Rates of first- and all-listed AMIs changed little. Rates of first-listed UA fell 87% from 29.7/10,000 in 1988 to 3.9/10,000 in 2001. This sharp decline was seen among all age and sex groups. Consequently, rates of ACS as a primary diagnosis declined 44%. In contrast, discharge rates for all-listed UA and ACS declined only modestly.

CONCLUSIONS

As a primary diagnosis, UA is disappearing. Rates of first-listed ACS are quite sensitive to the decline in UA. Although discharge data based on first-listed diagnoses have been used to estimate the national incidence of AMI, they may not provide accurate data regarding current trends for ACS.

B-type natriuretic peptide: a novel early blood marker of acute myocardial infarction in patients with chest pain and no ST-segment elevation

AIMS

This study was undertaken to determine the diagnostic value of admission B-type natriuretic peptide (BNP) for acute myocardial infarction (AMI) in patients with acute chest pain and no ST-segment elevation.

METHODS AND RESULTS

A prospective study with 631 consecutive patients was conducted in the emergency department. Non-ST elevation AMI was present in 72 patients and their median admission BNP level was significantly higher than in unstable angina and non-acute coronary syndrome patients. Sensitivity of admission BNP for AMI (cut-off value of 100 pg/mL) was significantly higher than creatine kinase-MB (CKMB) and troponin-I on admission (70.8 vs. 45.8 vs. 50.7%, respectively, P<0.0001) and specificity was 68.9%. Simultaneous use of these markers significantly improved sensitivity to 87.3% and the negative predictive value to 97.3%. In multiple logistic regression analysis, admission BNP was a significant independent predictor of AMI, even when CKMB and troponin-I were present in the model.

CONCLUSION

BNP is a useful adjunct to standard cardiac markers in patients presenting to the emergency department with chest pain and no ST-segment elevation, particularly if initial CKMB and/or troponin-I are non-diagnostic.

Predictors of short-term outcome in acute chest pain without ST-segment elevation

BACKGROUND

Management of acute chest pain in the emergency room constitutes a challenge.

METHODS

Seven hundred and one consecutive patients were evaluated by clinical history (chest pain score and risk factors), ECG, troponin I and early (<24 h) exercise testing in low risk patients (n=165). A composite end-point (recurrent unstable angina, acute myocardial infarction or cardiac death) was recorded during hospital stay or in ambulatory care settings for patients discharged after early exercise testing.

RESULTS

The end-point occurred in 122 patients (17%). Multivariate analysis identified the following predictors: chest pain score > or =11 points (OR=1.8, 2-2.8, 95% CI, P=0.007), age > or =68 (OR 1.6, 1.1-2.4 CI 95%, P=0.03), insulin-dependent diabetes mellitus (OR 1.9, 1.1-3.4 CI 95%, P=0.02), a history of coronary surgery (OR 3.3, 1.5-7.2 CI 95%, P=0.003), ST-segment depression (OR 1.9, 1.2-3.0 CI 95%, P=0.009) and troponin I elevation (OR 1.6, 1.1-2.5, CI 95%, P=0.05). ST-segment depression produced a high end-point increase (31 vs. 13%, P=0.0001). Troponin I elevation increased the risk in the subgroup without ST-segment depression (20 vs. 11%, P=0.006) but did not further modify the risk in the subgroup with ST depression (31 vs. 28%, ns). Nevertheless, the negative ECG and troponin I subgroup showed a non-negligible end-point rate (16% when pain score > or =11 or 7% when pain score <11, P=0.004). Finally, no patient with a negative exercise test presented events compared to 7% of those with a non-negative test (RR=2.5, 2.1-3.1 95% CI, P=0.01).

CONCLUSIONS

Emergency room evaluation of chest pain should not focus on a single parameter; on the contrary, the clinical history, ECG, troponin and early exercise testing must be globally analysed.

Psychological treatments for noncardiac chest pain: recommendations for a new approach

OBJECTIVE

Our objective is to describe the current state of treatment for NCCP, identify barriers to treatment and limitations of current approaches, and to recommend treatment strategies, which may address these challenges.

METHODS

We describe the underlying rationale for treating NCCP and review the current literature concerning NCCP treatments and other brief approaches to outpatient treatment for psychosomatic illness.

RESULTS

Most treatments for NCCP have been based on the Attribution Model. Although effective, these treatments are appropriate and acceptable to only a small minority of NCCP patients. The Biopsychosocial Model has been used to treat psychosomatic conditions in outpatient groups and may overcome or avoid many of the limitations inherent in current treatment strategies for NCCP.

CONCLUSIONS

We recommend an intervention for NCCP that is brief, would be delivered in the emergency department setting (to take advantage of the Teachable Moment), and which is based on the Biopsychosocial Model.

Acute chest pain — identification of patients at low risk for coronary events. The impact of symptoms, medical history and risk factors

BACKGROUND

The evaluation of patients with acute chest pain remains challenging, as it implies the risk of fatal misdiagnosis. It is well recognized that typical angina does not specifically identify patients at high risk. We investigated the predictive value of characteristics atypical for myocardial ischemia for exclusion of acute or subacute coronary events, focusing on patients' symptoms, medical history and risk factors.

METHODS

We prospectively studied 1288 consecutive patients presenting with acute chest pain at a non-trauma emergency department. Patients' symptoms, history and risk factors were evaluated using seven predefined criteria and assigned as typical or atypical for ischemic coronary chest pain. Positive predictive value (PPV) and 95% confidence intervals (95% CI) were calculated to predict or exclude acute myocardial infarction (AMI) and major adverse cardiac events (MACE: cardiovascular death, percutaneous coronary interventions, bypass surgery, or myocardial infarction) within six months.

RESULTS

AMI occurred in 168 patients (13%), and 6-months MACE (including AMI) overall in 240 patients (19%). Presence of four or more criteria typical for myocardial ischemia was associated with a PPV of 0.21 (0.17 to 0.25) for predicting AMI and 0.30 (0.25 to 0.35) for 6-months MACE. Presence of four or more criteria atypical for coronary ischemia was associated with a PPV of 0.94 (0.91 to 0.96) for excluding AMI and 0.93 (0.90 to 0.96) for excluding 6-months MACE. In 165 of 476 patients under 40 years of age (35%), four or more atypical criteria excluded AMI and 6-months MACE with PPVs of 0.98 (0.96 to 1.0).

CONCLUSION

Evaluation of criteria atypical for myocardial ischemia with acute chest pain may help to identify candidates for early discharge, whereas typical characteristics have very little diagnostic value.

[Chest pain in clinical practice: impact of routine troponin determination on clinical manifestations and care]

INTRODUCTION AND OBJECTIVES. To study the significance of chest pain in the clinical practice of a Spanish hospital and to evaluate the impact of routine troponin determination.

METHODS

In our institution, routine serial measurements of troponins I and T were made in the evaluation of chest pain in 2000. We compared the results obtained in 1999 for all patients who visited the emergency room for chest pain and the patients who were hospitalized. We recorded the diagnosis at discharge, duration of the hospital stay, and associated costs.

RESULTS

In 2000, 1,820 patients with chest pain visited the emergency department, which was equivalent to 1.9% of visits and 7.5 cases per 1,000 people and year: 43% of these patients were hospitalized for suspected acute coronary syndrome as compared to 49% in 1999 (-12%; p > 0.001). Among the patients admitted, 28% were discharged with a diagnosis of non-ischemic chest pain. Troponin determinations were associated with a lower probability of admission due to unstable angina (11.5 vs 16.0%; -28%; p < 0.001) and non-ischemic chest pain (12.1 vs 14.5%; -16%; p < 0.05), and an increase in diagnoses of non-Q wave acute myocardial infarction (3.4% vs 1.8%; +89%; p < 0.01). Non-ST elevation acute coronary syndrome ACS required 3,751 days of hospitalization and 1,003,420 euros of cost, and troponin determinations were associated with a reduction in hospital stays of 832 days (-18.2%) and 185,100 euros (-15.6%).

CONCLUSION

Chest pain had a high incidence, 7.5, and generates high costs in hospital admissions. The routine use of serial troponin determinations was associated with a reduction in hospital admissions due to unstable angina and non-ischemic chest pain, and costs.

Effectiveness of a multidisciplinary chest pain unit for the assessment of coronary syndromes and risk stratification in the Florence area

BACKGROUND

In patients seen at the emergency department (ED) with chest pain (CP), noninvasive diagnostic strategies may differentiate patients at high or intermediate risk from those at low-risk for cardiovascular events and optimize the use of high-cost resources. However, in welfare healthcare systems, the feasibility, accuracy, and potential benefits of such management strategy need further investigation.

METHODS

A total of 13,762 consecutive patients with CP were screened, and their conditions were defined as high, intermediate, and low risk for short-term cardiovascular events. Patients at high and intermediate risk were admitted. Patients at low risk were discharged from the ED if first line (<6 hours, including electrocardiogram, troponins, and serum cardiac markers) or second line short-term evaluation (<24 hours, including echocardiogram, rest or stress 99m-Tc myocardial scintigraphy, exercise tolerance test, or stress-echocardiography) had negative results. Patients with a diagnosis of coronary artery disease (CAD) were admitted. Patients without evidence of cardiovascular disease underwent screening for psychiatric and gastroesophageal disorders. Inhospital mortality rate was assessed in all patients.

RESULTS

Among patients at high and intermediate risk (n = 9335), 2420 patients had acute myocardial infarction (26%, 10.6% mortality rate), 3764 had unstable angina (40%, 1.1% mortality rate), 129 had aortic dissection (1.4%, 23.3% mortality rate), and 408 had pulmonary embolism (4%, 27.6% mortality rate). The remaining 2614 had chronic coronary heart disease in the context of multiple pathology (n = 2256) or pleural or pericardial diseases (n = 358). Among patients at low risk (n = 4427), 2672 were discharged at <6 hours (60%, 0.2% incidence rate of nonfatal CAD at 6 months) and 870 patients were discharged at <24 hours (20%, no CAD at follow-up). The remaining 885 patients were recognized as having CAD (20%, 1.1% inhospital mortality rate). Finally, half of the patients without CAD had active gastroesophageal or anxiety disorders.

CONCLUSION

An effective screening program with an observation area inside the ED (1) could be implemented in a public healthcare environment and contribute significantly to the reduction of admissions, (2) could optimize the management of patients at high and intermediate risk and succeed in recognizing CAD in 20% of patients at low risk, and (3) could allow screening for alternative causes of CP in patients without evidence of CAD.

Acute chest pain—a stepwise approach, the challenge of the correct clinical diagnosis

STUDY OBJECTIVE

To assess the safety and the accuracy of a 4 h stepwise diagnostic approach relying on clinical judgement in unselected patients with acute chest pain.

DESIGN

Prospective cohort study.

SETTING

Emergency department (ED) of a tertiary care university hospital.

PATIENTS

1288 unselected patients presenting with acute chest pain.

INTERVENTIONS

After history and physical examination, clinical judgement (step I), governed the need for further patient evaluation: baseline 12 lead electrocardiogramm (ECG) and laboratory examinations (step II), serial 12 lead ECG and laboratory examinations after 4 h (step III), and 4 h troponin T measurement (step IV) to exclude or to confirm a coronary origin of chest pain. Patients were followed clinically for 6 months for future occurrence of cardiac events (myocardial infarction, percutaneous transluminal coronary angioplasty (PTCA), CABG, cardiac death), any death and for accuracy of the ED diagnosis in non-coronary chest pain patients.

MEASUREMENTS AND RESULTS

Chest pain was diagnosed to be coronary in origin in 381 and non-coronary in 907 patients, respectively. Cardiac events occurred during follow up in 240 (19%) of 1288 patients, in 233 of 381 (61%) with presumed coronary and seven of 907 (1%) with presumed non-coronary chest pain. Sensitivity, specificity, positive predictive value and negative predictive value for correct detection of coronary chest pain were 97, 86, 61 and 99%, respectively. In non-coronary chest pain patients the agreement between the ED diagnosis and the final diagnosis was good (kappa=0.71, 95% confidence interval (CI) 0.67-0.75).

CONCLUSIONS

The 4 h stepwise approach guided by clinical judgement was safe for ruling out impending cardiac events in unselected patients with acute chest pain. However, more extensive evaluation is necessary for accurate rule-in of coronary chest pain.

The chest pain center strategy for delivering community heart attack care by shifting the paradigm of heart attack care to earlier detection and treatment

Heart attack remains the number one health problem in the United States and throughout the world. It has been that way for more than 100 years. Unless we change our course, heart attack will continue to exert its horrendous casualties, not only in the United States but also throughout the world. Our present strategy in dealing with this problem needs both leadership and a change in direction. In an effort to search "outside the box" for the solution to this problem, this symposium is a call to action that challenges us to approach the heart attack problem with a mindset bent on winning this war against heart disease, and not coexisting and accepting the problem as an inescapable fate.

[Chest pain units: state of the art of the management of patients with chest pain in the emergency department]

Chest pain is one of the most common reasons for patients coming to emergency departments. Most of these individuals end up being hospitalized due to uncertainty of the cause of their complaint. This aggressive and defensive attitude is taken by emergency physicians because some 10 to 30% of these patients actually have acute coronary syndrome. As the admission electrocardiogram and serum CK-MB level have a sensitivity of about 50% for the diagnosis of acute myocardial infarction, serial evaluation is mandatory for non-low risk patients. Inspite of this knowledge, an average of 2-3% of patients with acute myocardial infarction are erroneously released from emergency departments, what is responsible for expensive malpractice suits in the United States. Chest Pain Units were introduced in emergency practice two decades ago to improve medical care quality, reduce inappropriate hospital discharges, reduce unnecessary hospital admissions and reduce medical costs, thus making patient's assessment cost-effective. This is achieved mostly with the use of systematic diagnostic protocols by qualified and trained personnel in the emergency department setting and not in the coronary care unit.

THE CHEST PAIN CENTER IN THE EMERGENCY DEPARTMENT

Despite the improvement of medical treatment for acute coronary syndromes throughout the 20th century, the authors believe that many cases of life-threatening coronary events could be avoided through early detection of CAD and the use of preventive strategies. Establishing chest pain units that are linked to the ED is one excellent strategy to risk-stratify patients with symptoms who are at risk for sustaining an AMI or having lethal arrhythmias. There is a need for more research on chest pain units to determine the value for cost and to further optimize strategies for ACI detection and screening. In EDs with high volumes of chest pain patients, or high pressures to avoid hospital admissions, a planned, systematic, and rapid approach to the treatment of AMI and the diagnosis of chest pain is a rewarding necessity.

Maximizing use of the emergency department observation unit: a novel hybrid design

STUDY OBJECTIVE

We sought to determine whether sharing an observation unit with scheduled procedure patients would maintain a more consistent unit census and patient/nurse ratio. A secondary objective was to determine the effect of this model on patient length of stay and discharge rates.

METHODS

This retrospective, descriptive study was conducted in a high-volume suburban teaching hospital, using a "before-and-after" study design. A "pure" postprocedure unit became a "hybrid" observation postprocedure unit by displacing specific postprocedure patients to inpatient locations. Subsequently, the displaced patients were returned to the unit. On weekends, the unit operated as a pure observation unit. Hourly unit occupancy and census data were prospectively collected, and hourly patient/nurse ratios were calculated. Patient length of stay and discharge data were collected and compared in different settings.

RESULTS

The 2 services showed a complementary census pattern that allowed the hybrid unit to maintain an average hourly patient/nurse ratio of 3.7 compared with the ratio of 2.5 for a pure observation unit. There was no difference in observation patient length of stay (14.8 hours versus 14.7 hours) or discharge rate (20.4% versus 18.1%) between weekdays and weekends. However, scheduled procedure patients experienced significantly shorter lengths of stay in the hybrid unit setting (4.3 hours) than in alternative inpatient locations (9.4 hours).

CONCLUSION

The hybrid model showed better hourly census and nurse resource use rates, with no adverse effect on observation patients. However, scheduled procedure patient length of stay was shorter in this setting.

Economic issues in observation unit medicine

Emergency department observation units are the rational choice for improving the utilization of health care resources and at the same time improving the quality of patient care. Potential pitfalls can be avoided by flexibility on both the part of the observation unit and the hospital administration staff. The continued growth of observation medicine throughout the country is evidence that most have been successful in designing creative solutions to accommodate this new health service.

Principles of observation medicine

The defining characteristic of emergency medicine is "time," or the acuity of disease presentation. Observation, like resuscitation, involves the management of time-sensitive conditions. In the ED there is a continuum of time-sensitive conditions. This continuum extends from resuscitation on one end to observation on the other. When performed well, observation services have been shown to improve diagnostic accuracy, improve treatment outcomes, decrease costs, and improve patient satisfaction. For the subset of ED patients who would have been inappropriately discharged or unnecessarily admitted, the OU has become a safety net of the ED itself. Like EDs, OUs have progressed from being poorly managed areas of the hospital to the cutting edge of acute health care. The principles developed through past experience and research provide a framework for future developments in emergency medicine.

Usefulness of pharmacologic stress echocardiography in a chest pain center

We tested the value of a stress echocardiography-based algorithm used in a chest pain center. The algorithm had superlative negative predictive value for cardiac events, allowing an early discharge.

Triage of patients for a rapid (5-minute) electrocardiogram: A rule based on presenting chief complaints

STUDY OBJECTIVE

A rule based on presenting chief complaints can identify patients for a rapid (5-minute) ECG and decrease delays in treatment of patients with acute myocardial infarction (MI).

METHODS

The presenting chief complaint was electronically collected on all patients treated in a community teaching hospital emergency department. A rule for ordering ECG on patient presentation to the ED was developed from a model set of patients presenting from July through December 1994 (22,717 patients) and then tested on a validation set of patients from January through May 1995 (18,759 patients). Outcome measures (delay in performance of ECG and delay in administration of thrombolytic agents) were prospectively collected on written data sheets before (April 1993-May 1995, n=67) and after (June 1995-March 1997, n=128) implementation of the rule at the study hospital.

RESULTS

On the model set, 193 patients had the final diagnosis of MI, with 5 chief complaints having the best performance in identifying patients with acute MI and comprising the rapid ECG rule: older than 30 years with chest pain (130 [67.4%] patients); older than 50 years with syncope (5 [1%] patients); weakness (12 [6.2%] patients); rapid heart beat (2 [1%] patients); and difficulty breathing or shortness of breath (20 [10.4%] patients). On the validation set, 142 patients had the final diagnosis of MI, with the rule performing better than chest pain in identifying patients for a "stat" ECG (sensitivity 93.7% versus 67. 4% [95% confidence interval (CI) of the difference, 15.6% to 33.8%]), although a larger percentage of ED patients would receive a stat ECG (7.3% versus 6.3% [95% CI of the difference, 0.7% to 1.7%]). During the model and validation period, 44 (13.1%) of 335 patients with MI received thrombolytic agents. The rule had higher sensitivity on patients with MI treated with thrombolytic agents compared with patients with MI not treated with thrombolytic agents (sensitivity 100% versus 86.4% [95% CI of the difference, 1.7% to 20. 3%] and specificity of 90.4% versus 93.8% [95% CI of the difference, 3.0% to 3.8%]). For the 4-year study period, outcome improved after the implementation of the rule: mean delay in performing ECGs in patients with MI who were administered thrombolytic agents decreased from 10.0 to 6.3 minutes (95% CI of the difference, 1.1 to 6.4), and mean delay in administering thrombolytic agents decreased from 36.9 to 26.1 minutes (95% CI of the difference, 3.5 to 17.7).

CONCLUSION

Use of a rule based on chief complaints can identify patients with MI for immediate ECG and decrease delays in performing ECGs and administration of thrombolytic agents.

Provocative testing for chest pain

Since the first Chest Pain Center (CPC) was set up in 1981 to speed up the evaluation and treatment of patients with acute myocardial infarction, the original concept has been expanded to include rapid evaluation of chest pain patients with the appropriate streamlining of care and incorporation of the latest in technology. It has also been established that among patients presenting with acute chest pain, a very low-risk group with less than 5% probability of a coronary event can be identified. The recognition of this group could prevent unnecessary admissions, affording more appropriate patient care and improved cost-effectiveness. The efficient management of these chest pain patients requires that there be reductions in: (1) delays in therapy, (2) "soft" admissions, (3) inappropriate dispositions, and (4) cost. With time, provocative testing (PT) for chest pain patients has been brought forward to the frontline. PT methods are now being studied in hundreds of emergency department (ED) patients, followed up over several months to ascertain the predictive value of both positive and negative test results. More and more CPCs are now using PT as part of their management protocol, in terms of decision-making pertaining to prognostification, treatment and disposition. This could be in the form of the ECG graded exercise test (GXT), stress echocardiography (SE) and stress single-photon emission computed tomography (SPECT) radionuclide perfusion imaging. The GXT is fairly widely used currently, SE is gaining popularity and stress radionuclide perfusion imaging will perhaps gain more acceptance as the experience with its use as well as the number of randomized controlled studies increase. As we move into the new millennium, the emergency physicians must familiarize themselves with the latest in the state-of-the-art concepts and technology to render improved, up-to-date and more cost-effective patient care.

Implementing emergency department observation units within a multihospital network

BACKGROUND

The proportion of emergency department (ED) chest pain patients who undergo an extended "rule out MI (myocardial infarction)" evaluation beyond the ED determines both the quality and cost of patient care. The higher an organization's rate of such evaluations, the lower the average miss rate for MI. Five of the 13 hospitals in the Voluntary Hospital Association Northeast multihospital network implemented ED observation units by June 1997 for outpatient rule out MI evaluations.

RESULTS

Compared with historical and case controls, the five hospitals with ED observation units had a higher observation rate (16% versus 0% [p < .001] and 2% [p < .001]) and a higher rule out MI evaluation rate (61% versus 46% [p < .01] and 45% [p < .01]), without a significantly higher admission rate (47% versus 46% and 45%). For the three hospitals with observation units that collected charge data during 1997 on a consecutive series of chest pain patients who had negative rule out MI evaluations, charges for patient services were lower for patients evaluated in the ED observation unit ($2,214.80 +/- $80.40) than in the hospital ($5,464.30 +/- $393.60).

CONCLUSIONS

ED observation units represent a cost-effective restructuring of the diagnostic approach to patients with acute chest pain. In an improvement of quality of patient care, a larger proportion of ED chest pain patients receive an extended evaluation than is possible with hospital admission as the only ED disposition option.