Safety and Efficiency of a Chest Pain Diagnostic Algorithm With Selective Outpatient Stress Testing for Emergency Department Patients With Potential Ischemic Chest Pain

doi:10.1016/j.annemergmed.2011.10.016

Annals of Emergency Medicine

Volume 59, Issue 4, April 2012, Pages 256-264.e3

https://doi.org/10.1016/j.annemergmed.2011.10.016 Get rights and content

Study objective

Chest pain units have been used to monitor and investigate emergency department (ED) patients with potential ischemic chest pain to reduce the possibility of missed acute coronary syndrome. We seek to optimize the use of hospital resources by implementing a chest pain diagnostic algorithm.

Methods

This was a prospective cohort study of ED patients with potential ischemic chest pain. High-risk patients were referred to cardiology, and patients without ECG or biomarker evidence of ischemia were discharged home after 2 to 6 hours of observation. Emergency physicians scheduled discharged patients for outpatient stress ECGs or radionuclide scans at the hospital within 48 hours. Patients with positive provocative test results were immediately referred back to the ED. The primary outcome was the rate of missed diagnosis of acute coronary syndrome at 30 days.

Results

We prospectively followed 1,116 consecutive patients who went through the chest pain diagnostic algorithm, of whom 197 (17.7%) were admitted at the index visit and 254 (22.8%) received outpatient testing on discharge. The 30-day acute coronary syndrome event rate was 10.8%, and the 30-day missed acute coronary syndrome rate was 0% (95% confidence interval 0% to 2.4%). Of the 120 acute coronary syndrome cases, 99 (82.5%) were diagnosed at the index ED visit, and 21 patients (17.5%) received the diagnosis during outpatient stress testing.

Conclusion

In ED patients with chest pain, a structured diagnostic approach with time-focused ED decision points, brief observation, and selective application of early outpatient provocative testing appears both safe and diagnostically efficient, even though some patients with acute coronary syndrome may be discharged for outpatient stress testing on the index ED visit.

Introduction

Approximately 15% to 25% of patients presenting to an emergency department (ED) with chest pain receive a diagnosis of acute coronary syndrome within 30 days, and between 2% and 5% of these patients are discharged inappropriately after receiving an incorrect minimizing diagnosis.1, 2 To improve early diagnostic accuracy, the 2007 American College of Cardiology/American Heart Association non-ST-elevation myocardial infarction guidelines recommend observation and serial investigations for up to 12 hours, followed by provocative cardiac testing, preferably with inpatients, but with outpatients if testing results can be obtained within 72 hours.³ Although the medical and legal consequences of missed acute coronary syndrome are high, hospital resources may not be sufficient to admit, observe, monitor, and investigate all at-risk patients. Keeping such patients in EDs may worsen crowding, which has been associated with a lower standard of care and increased incidence of adverse events in cardiac patients.4, 5, 6

To address these concerns, many hospitals have implemented chest pain observation units.7, 8, 9, 10, 11, 12, 13, 14, 15 Diagnostic algorithms vary by institution, but most units observe and monitor patients with potential cardiac ischemia, obtain serial cardiac biomarker and ECG results, and conduct provocative cardiac testing. Patients with negative chest pain unit investigation results are discharged, whereas those with worrisome results are hospitalized, and lengths of stay vary from 9 to 50 hours.7, 8, 9, 10, 11 Meyer et al discharged ED patients at low risk for cardiac ischemia and arranged for 72-hour outpatient provocative stress testing; 18 of 903 (2%) patients who were discharged with outpatient testing required cardiac revascularization within 6 months.¹¹

In a previous study at our institution, in which emergency physicians used an individualized approach to patients with potential ischemia, we found that 35% of patients were admitted, median ED length of stay was 6.5 hours, and our 30-day acute coronary syndrome “miss” rate was 5.3%.⁴ To improve diagnostic accuracy, safety, and resource use at our hospital, collaborators from the Departments of Emergency Medicine, Cardiology, and Nuclear Medicine developed an algorithm to provide a streamlined approach to patients with potential cardiac chest pain. This intervention combined brief ED observation with expedited outpatient provocative testing when indicated. We hypothesized that this diagnostic strategy would provide a low (<2%) acute coronary syndrome miss rate while maintaining a median ED length of stay at approximately 6 hours.

Section snippets

Setting

St Paul's Hospital in Vancouver, British Columbia, is an inner-city teaching hospital and provincial referral center affiliated with the University of British Columbia. The ED has an annual census of 60,000, and the hospital is a cardiac center with a 24-hour catheterization laboratory; cardiac surgery, including transplants; and 12-bed coronary care unit. This prospective cohort study was conducted between February and September 2006.

Triage nurses identified patients with potential ischemic

Results

During the study period, 1,255 consecutive patients presented with a triage code of “chest pain, cardiac features.” We analyzed 1,194 (95.1%) patients in the chest pain diagnostic algorithm protocol, with 54 exclusions (Figure 1). Of 1,140 eligible patients, 24 (2.1%) were lost to follow-up, but none of these patients had a regional ED visit or died within 30 days. Table 1 summarizes baseline characteristics and Table 2 describes clinical outcomes for the study cohort, showing that the acute

Limitations

This was a single-center cohort study performed in an inner-city Canadian ED with comprehensive cardiology services, and these results may be difficult to reproduce in other settings. The observational design is not ideal, but a randomized trial in our institution was not possible. Once the intervention was in place, subjecting patients to previous care without rapid outpatient testing was not considered ethical. Although an ideal comparison would have been similar structured care with

Discussion

In this intensive 30-day follow-up study of 1,116 ED patients with potential ischemic chest pain, 120 patients had definite acute coronary syndrome and 0% were missed (95% confidence interval 0% to 2.4%) with the diagnostic algorithm described. These results compare favorably to the 5% miss rate observed in an earlier chest pain cohort at the same setting before the implementation of the accelerated diagnostic protocol,⁴ whereas the median ED length of stay was similar.

Enhanced diagnostic

References (26)

J.L. Anderson et al.
ACC/AHA 2007 guidelines for the management of patients with unstable angina/non–ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction)
J Am Coll Cardiol
(2007)
D.B. Diercks et al.
Prolonged emergency department stays of non–ST-segment elevation myocardial infarction patients are associated with worse adherence to the American College of Cardiology/American Heart Association guidelines for management and increased adverse events
Ann Emerg Med
(2007)
M.A. Gomez et al.
An emergency department–based protocol for rapidly ruling out myocardial ischemia reduces hospital time and expense: results of a randomized study (ROMIO)
J Am Coll Cardiol
(1996)
M. Chase et al.
Prospective validation of the Thrombolysis in Myocardial Infarction risk score in the emergency department chest pain population
Ann Emerg Med
(2006)
F.M. Fesmire et al.
The Erlanger chest pain evaluation protocol: a one-year experience with serial 12-lead ECG monitoring, two-hour delta serum marker measurements, and selective nuclear stress testing to identify and exclude acute coronary syndromes
Ann Emerg Med
(2002)
W.V. Gibler et al.
A rapid diagnostic and treatment center for patients with chest pain in the emergency department
Ann Emerg Med
(1995)
A.B. Storrow et al.
Chest pain centers: diagnosis of acute coronary syndromes
Ann Emerg Med
(2000)
J.H. Pope et al.
Missed diagnoses of acute cardiac ischemia in the emergency department
N Engl J Med
(2000)
J. Christenson et al.
Safety and efficiency of emergency department assessment of chest discomfort
CMAJ
(2004)
J. Greene
The perils of low-risk chest pain: emergency physicians struggle to balance risk with overtesting
Ann Emerg Med
(2010)

J.M. Pines et al.

The association between emergency department crowding and adverse cardiovascular outcomes in patients with chest pain

Acad Emerg Med

(2009)

M.E. Farkouh et al.

A clinical trial of a chest pain observation unit for patients with unstable angina

N Engl J Med

(1998)

R.R. Roberts et al.

Costs of an emergency department–based accelerated diagnostic protocol vs hospitalization in patients with chest pain. A randomized controlled trial

JAMA

(1997)

Cited by (49)

Disparities in cardiovascular outcomes among emergency department patients with mental illness
2022, American Journal of Emergency Medicine
Patients with mental illness have been shown to receive lower quality of care and experience worse cardiovascular (CV) outcomes compared to those without mental illness. This present study examined mental health-related disparities in CV outcomes after an Emergency Department (ED) visit for chest pain.
This retrospective cohort included adult Medicaid beneficiaries in Washington state discharged from the ED with a primary diagnosis of unspecified chest pain in 2010–2017. Outcomes for patients with any mental illness (any mental health diagnosis or mental-health specific service use within 1 year of an index ED visit) and serious mental illness (at least two claims (on different dates of service) within 1 year of an index ED visit with a diagnosis of schizophrenia, other psychotic disorder, or major mood disorder) were compared to those of patients without mental illness. Our outcomes of interest were the incidence of major adverse cardiac events (MACE) within 30 days and 6 months of discharge of their ED visit, defined as a composite of death, acute myocardial infarction (AMI), CV rehospitalization, or revascularization. Secondary outcomes included cardiovascular diagnostic testing (diagnostic angiography, stress testing, echocardiography, and coronary computed tomography (CT) angiography) rates within 30 days of ED discharge. Only treat-and-release visits were included for outcomes assessment. Hierarchical logistic random effects regression models assessed the association between mental illness and the outcomes of interest, controlling for age, gender, race, ethnicity, Elixhauser comorbidities, and health care use in the past year, as well as fixed year effects.
There were 98,812 treat-and-release ED visits in our dataset. At 30 days, enrollees with any mental illness had no differences in rates of MACE (AOR 0.96; 95% CI, 0.72–1.27) or any of the individual components. At 6 months, enrollees with any mental illness (AOR 1.86; 95% CI, 1.11–3.09) and serious mental illness (AOR 2.60; 95% CI 1.33–5.13) were significantly more likely to be hospitalized for a CV condition compared to those without mental illness. Individuals with any mental illness had higher rates of testing at 30 days (AOR 1.16; 95% CI 1.07–1.27).
Patients with mental illness have similar rates of MACE, but higher rates of certain CV outcomes, such as CV hospitalization and diagnostic testing, after an ED visit for chest pain.
Diagnostic Accuracy of History and Physical Examination for Predicting Major Adverse Cardiac Events Within 30 Days in Patients With Acute Chest Pain
2020, Journal of Emergency Medicine
The cornerstones in the assessment of emergency department (ED) patients with suspected acute coronary syndrome (ACS) are patient history and physical examination, electrocardiogram, and cardiac troponins. Although there are several prior studies on this subject, they have in some cases produced inconsistent results.
The aim of this study was to evaluate the diagnostic and prognostic accuracy of elements of patient history and the physical examination in ED chest pain patients for predicting major adverse cardiac events (MACE) within 30 days. Methods: This was a prospective observational study that included 1167 ED patients with nontraumatic chest pain. We collected clinical data during the initial ED assessment of the patients. Our primary outcome was 30-day MACE.
Pain radiating to both arms increased the probability of 30-day MACE (positive likelihood ratio [LR+] 2.7), whereas episodic chest pain lasting seconds (LR+ 0.0) and >24 h (LR+ 0.1) markedly decreased the risk. In the physical examination, pulmonary rales (LR+ 3.0) increased the risk of 30-day MACE, while pain reproduced by palpation (LR+ 0.3) decreased the risk. Among cardiac risk factors, a history of diabetes (LR+ 3.0) and peripheral arterial disease (LR+ 2.7) were the most predictive factors.
No clinical findings reliably ruled in 30-day MACE, whereas episodic chest pain lasting seconds and pain lasting more than 24 h markedly decreased the risk of 30-day MACE. Consequently, these two findings can be adjuncts in ruling out 30-day MACE.
Can a HEART Pathway Improve Safety and Diagnostic Efficiency for Patients With Chest Pain?
2019, Annals of Emergency Medicine
Clinical Policy: Critical Issues in the Evaluation and Management of Emergency Department Patients With Suspected Non–ST-Elevation Acute Coronary Syndromes
2018, Annals of Emergency Medicine
Citation Excerpt :
Limitations of the analysis included substantial statistical heterogeneity between studies and lack of consistent reporting of cardiac marker assays, types, and thresholds. Twelve Class III studies24-28,31,33,35,36,38,39,60 examined the utility of conventional, nonhigh-sensitivity troponins in formulating TIMI score for predicting 30-day MACE. One of the earliest was a secondary analysis of a prospective cohort of ED patients presenting with chest pain.24
Performance of an outpatient stress testing protocol for low risk chest pain patients presenting to the emergency department
2017, American Journal of Emergency Medicine
An end-user's guide to the HEART score and pathway
2017, American Journal of Emergency Medicine
Citation Excerpt :
However, moderate risk patients display a 12%–16.6% risk of MACE [20-27]. Stress testing modalities are advocated for further risk stratification, but the benefits of stress testing are controversial at best [6-12]. Currently, several societies recommend risk stratification with these modalities [41-43].
Chest pain accounts for a significant percentage of emergency department (ED) presentations. The HEART score and pathway have demonstrated an ability to appropriately risk stratify and discharge from the ED a significant proportion of patients.
This review evaluates vital components of the HEART score and pathway, while discussing important considerations for current and future use.
Chest pain is a common ED presentation, and several conditions associated with chest pain result in patient morbidity and mortality. One major disease is acute coronary syndrome (ACS). Despite the fear associated with this disease, it accounts for a minority of patients with chest pain in the ED. Emergency physicians rarely miss myocardial infarction (MI) or ACS, with miss rates < 1%. Many have sought a score and pathway that allow physicians to safely and reliably risk stratify patients. The HEART score and pathway have revolutionized chest pain evaluation, as they can risk stratify a significant number of patients accurately into separate categories based on history, electrocardiogram (ECG), troponin, age, and risk factors while displaying high sensitivity for MACE. Several intricacies must be considered in the use of this score including risk factors, ECG, troponin, age, history, gestalt, follow up, borderline score, and shared decision making. The HEART pathway can supplement clinician decision making.
Appropriate use of the HEART pathway reliably risk stratifies patients. Physicians must consider several key components when utilizing the HEART pathway, and future directions may incorporate other patient factors.

View all citing articles on Scopus

: Provide feedback on this article at the journal's Web site, www.annemergmed.com.

: A podcast for this article is available at www.annemergmed.com.

: Supervising editor: Deborah B. Diercks, MD

: Author contributions: GI, EG, MK, DK, and JC developed the chest pain diagnostic algorithm. FS and JC conceived the study. BB supervised the conduct of the trial and data collection. BB and EY managed the database. FS provided statistical analysis. FS drafted the article, and all authors contributed to its revision, notably GI and JC. FS takes responsibility for the paper as a whole.

: Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist.

: Please see page 257 for the Editor's Capsule Summary of this article.

: Publication date: Available online January 4, 2012.

View full text

Cardiology/original researchSafety and Efficiency of a Chest Pain Diagnostic Algorithm With Selective Outpatient Stress Testing for Emergency Department Patients With Potential Ischemic Chest Pain

Study objective

Methods

Results

Conclusion

Introduction

Section snippets

Setting

Results

Limitations

Discussion

J Am Coll Cardiol

Ann Emerg Med

J Am Coll Cardiol

Ann Emerg Med

Ann Emerg Med

Ann Emerg Med

Ann Emerg Med

Missed diagnoses of acute cardiac ischemia in the emergency department

N Engl J Med

Safety and efficiency of emergency department assessment of chest discomfort

CMAJ

The perils of low-risk chest pain: emergency physicians struggle to balance risk with overtesting

Ann Emerg Med

The association between emergency department crowding and adverse cardiovascular outcomes in patients with chest pain

Acad Emerg Med

A clinical trial of a chest pain observation unit for patients with unstable angina

N Engl J Med

Costs of an emergency department–based accelerated diagnostic protocol vs hospitalization in patients with chest pain. A randomized controlled trial

JAMA

Cardiology/original research
Safety and Efficiency of a Chest Pain Diagnostic Algorithm With Selective Outpatient Stress Testing for Emergency Department Patients With Potential Ischemic Chest Pain