Comparison of early dobutamine stress echocardiography and exercise electrocardiographic testing for management of patients presenting to the emergency department with chest pain

Representation of Older Adults and Women in Randomized Trials of Non-Invasive Imaging for Chest Pain

Background

Non-invasive imaging is widely used both for initial diagnosis and to guide management of ischemic heart disease (IHD). Older adults and women with IHD may have different responses to imaging as well as to treatments and outcomes that follow compared with younger adults and men. We aimed to study the representation of older adults and women in randomized controlled trials (RCT) of non-invasive imaging among patients with acute and stable chest pain.

Methods

We conducted a systematic search to identify RCTs evaluating non-invasive, imaging-guided diagnosis and management for IHD that were published before September 1, 2023. Participation-to-Prevalence Ratio (PPR) was estimated for women and age subgroups of <65, 65-74, ≥75 years. PPR of <0.8, 0.8-1.2, and >1.2 indicated underrepresentation, appropriate representation, and overrepresentation, respectively.

Results

Among 53 RCTs, sex and age breakdown were available in 53 (n=55,893) and 21 trials (n=35,503), respectively. The median age across all trials was 57.4 years [IQR: 55.0- 60.2]. Participants aged <65 years were overrepresented with a median PPR 2.13 [IQR: 1.73- 2.43], while those aged 65-74 years and ≥75 years were underrepresented with median PPRs of 0.74 [IQR: 0.56-0.83] and 0.21 [IQR: 0.11-0.33], respectively. Women were adequately represented with a median PPR of 1.2 [1.06-1.32].

Conclusion

While women were appropriately represented, adults 65 years or older, especially those ≥75 years, were under-represented in these trials. Future RCTs on non-invasive imaging should target enrollment of older adults to ensure generalizability of results to this growing population.

CLINICAL PERSPECTIVE

In a systematic review of 53 randomized controlled trials of non-invasive imaging for chest pain published before September 1, 2023 (n=55,893 participants), adults aged 65 years and older, especially those aged 75 years and above, were significantly underrepresented, whereas women had representation proportional to prevalence estimates. These findings highlight an urgent need to increase enrollment of older adults in future imaging trials to ensure broader applicability and relevance of study results.

Abstract Figure

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

STRUCTURE

Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. This guideline presents an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated, and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

STRUCTURE

Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. This guideline presents an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated, and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

STRUCTURE

Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. These guidelines present an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered. Structure: Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. This guideline presents an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated, and shared decision-making with patients is recommended.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered. Structure: Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. These guidelines present an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated and shared decision-making with patients is recommended.

Comparison of two strategies in a chest pain unit: stress echocardiography and multidetector computed tomography

INTRODUCTION AND OBJECTIVES

This study aimed to compare stress echocardiography (SE) and multidetector computed tomography (MCT) in patients admitted to a chest pain unit to detect acute coronary syndrome (ACS).

METHODS

A total of 203 patients with ≥ 1 cardiovascular risk factor, no ischemic electrocardiogram changes and negative biomarkers were randomized to SE (n=103) or MTC (n=100). The primary endpoint was a combination of hard events (death and nonfatal myocardial infarction), revascularizations, and readmissions during follow-up. The secondary endpoint was the cost of the 2 strategies.

RESULTS

Invasive angiography was performed in 61 patients (34 [33%] in the SE group and in 27 [27%] in the MCT group, P=.15). A final diagnosis of ACS was made in 53 patients (88% vs 85%, P=.35). There were no significant differences between groups in the primary endpoint (42% vs 41%, P=.91), or in hard events (5% vs 7%, P=.42). There were no significant differences in overall cost, but costs were lower in patients with negative SE than in those with negative MCT (€557 vs €706, P <.02).

CONCLUSIONS

No significant differences were found in efficacy and safety for the stratification of patients with a low to moderate probability of ACS admitted to a chest pain unit. The cost of the 2 strategies was similar, but cost was significantly lower for SE on comparison of negative studies.

ACR Appropriateness Criteria® Chest Pain-Possible Acute Coronary Syndrome

Chest pain is a frequent cause for emergency department visits and inpatient evaluation, with particular concern for acute coronary syndrome as an etiology, since cardiovascular disease is the leading cause of death in the United States. Although history-based, electrocardiographic, and laboratory evaluations have shown promise in identifying coronary artery disease, early accurate diagnosis is paramount and there is an important role for imaging examinations to determine the presence and extent of anatomic coronary abnormality and ischemic physiology, to guide management with regard to optimal medical therapy or revascularization, and ultimately to thereby improve patient outcomes. A summary of the various methods for initial imaging evaluation of suspected acute coronary syndrome is outlined in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Does an imaging stress-test adds information to prognostic scores in patients with chest pain in the emergency department?

We evaluated the ability of a stress-test (Str-T) to improve the risk stratification based on prognostic scores in patients presenting to the ED with chest pain. Between 2008, June and 2013, December, 1082 patients with chest pain were evaluated with an imaging Str-T. With a retrospective analysis, patients were stratified according to: (1) Florence Prediction Rule as low (0-1, LR-FPR), intermediate (2-4, IR-FPR), high risk (5-6, HR-FPR), respectively, 26, 50 and 24% of patients; (2) HEART score as LR-HEART, (0-3) and HR-HEART (≥4), respectively, 36 and 64%; (3) likelihood of CAD according to NICE guidelines, 10-29% LR-NICE, 30-60% IR-NICE and > 60% HR-NICE, respectively, 12, 18 and 70%. Scores' diagnostic performance was calculated with Str-T as reference. One-month follow-up by a phone call was performed, to investigate the occurrence of new cardiovascular events. In LR and HR patients, FPR and NICE score showed sensitivity 66 vs 93%, specificity 59 vs 19% (both p < 0.001), Positive Predictive Value (PPV) 36 vs 31%, Negative Predictive Value (NPV) 83 vs 87%. Among LR-HEART patients, Str-T was positive for inducible ischemia in 53 (14%) patients and 12 (4%) of them underwent a percutaneous coronary revascularization. The Str-T was negative for inducible ischemia in 760 (70%) patients, positive in 272 (25%), inconclusive in 50 (5%); among patients in the LR and IR subgroups, incidence of CAD (1.3 and 1.6%) and the cumulative incidence of significant events at 1-month follow-up (both 1%) was very low Str-T improved prognostic scores' diagnostic performance in LR- and HR-subgroups.

Outcomes of non-invasive diagnostic modalities for the detection of coronary artery disease: network meta-analysis of diagnostic randomised controlled trials

OBJECTIVE

To evaluate differences in downstream testing, coronary revascularisation, and clinical outcomes following non-invasive diagnostic modalities used to detect coronary artery disease.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

Medline, Medline in process, Embase, Cochrane Library for clinical trials, PubMed, Web of Science, SCOPUS, WHO International Clinical Trials Registry Platform, and Clinicaltrials.gov.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Diagnostic randomised controlled trials comparing non-invasive diagnostic modalities in patients presenting with symptoms suggestive of low risk acute coronary syndrome or stable coronary artery disease.

DATA SYNTHESIS

A random effects network meta-analysis synthesised available evidence from trials evaluating the effect of non-invasive diagnostic modalities on downstream testing and patient oriented outcomes in patients with suspected coronary artery disease. Modalities included exercise electrocardiograms, stress echocardiography, single photon emission computed tomography-myocardial perfusion imaging, real time myocardial contrast echocardiography, coronary computed tomographic angiography, and cardiovascular magnetic resonance. Unpublished outcome data were obtained from 11 trials.

RESULTS

18 trials of patients with low risk acute coronary syndrome (n=11 329) and 12 trials of those with suspected stable coronary artery disease (n=22 062) were included. Among patients with low risk acute coronary syndrome, stress echocardiography, cardiovascular magnetic resonance, and exercise electrocardiograms resulted in fewer invasive referrals for coronary angiography than coronary computed tomographic angiography (odds ratio 0.28 (95% confidence interval 0.14 to 0.57), 0.32 (0.15 to 0.71), and 0.53 (0.28 to 1.00), respectively). There was no effect on the subsequent risk of myocardial infarction, but estimates were imprecise. Heterogeneity and inconsistency were low. In patients with suspected stable coronary artery disease, an initial diagnostic strategy of stress echocardiography or single photon emission computed tomography-myocardial perfusion imaging resulted in fewer downstream tests than coronary computed tomographic angiography (0.24 (0.08 to 0.74) and 0.57 (0.37 to 0.87), respectively). However, exercise electrocardiograms yielded the highest downstream testing rate. Estimates for death and myocardial infarction were imprecise without clear discrimination between strategies.

CONCLUSIONS

For patients with low risk acute coronary syndrome, an initial diagnostic strategy of stress echocardiography or cardiovascular magnetic resonance is associated with fewer referrals for invasive coronary angiography and revascularisation procedures than non-invasive anatomical testing, without apparent impact on the future risk of myocardial infarction. For suspected stable coronary artery disease, there was no clear discrimination between diagnostic strategies regarding the subsequent need for invasive coronary angiography, and differences in the risk of myocardial infarction cannot be ruled out.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registry no CRD42016049442.

Association of Early Stress Testing with Outcomes for Emergency Department Evaluation of Suspected Acute Coronary Syndrome

BACKGROUND

Professional society guidelines suggest early stress testing (within 72 hours) after an emergency department (ED) evaluation for suspected acute coronary syndrome (ACS). However, there is increasing concern that current practice results in over-testing without evidence of benefit. We test the hypothesis that early stress testing improves outcomes.

METHODS

We analyzed prospectively collected data from 9 EDs on patients with suspected ACS, 1999-2001. We excluded patients with an ED diagnosis of ACS. The primary outcome was 30-day major adverse cardiac events (MACEs), including all-cause death, acute myocardial infarction, and revascularization. We used the HEART score to determine pretest ACS risk (low, intermediate, and high). To mitigate potential confounding, patients with and without early stress testing were matched within pretest risk strata in a 1:2 ratio using propensity scores.

RESULTS

Of 7127 potentially eligible patients, 895 (13%) received early stress testing. The analytic cohort included 895 patients with early stress testing matched to 1790 without early stress testing. The overall 30-day MACE rate in both the source and analytic population was 3%. There were no baseline imbalances after propensity score matching (P > 0.1 for more than 30 variables). There was no association between early stress testing and 30-day MACE [odds ratio, 1.0; 95% confidence interval (CI), 0.6-1.7]. There was no effect modification by pretest risk (low: odds ratio, 1.0; 95% CI, 0.2-3.7; intermediate: 1.2; 95% CI, 0.6-2.6; high: 0.4; 95% CI, 0.1-1.6).

CONCLUSIONS

Early stress testing is not associated with reduced MACE in patients evaluated for suspected ACS. Early stress testing may have limited value in populations with low MACE rate.

Noninvasive cardiac imaging in suspected acute coronary syndrome

Noninvasive cardiac imaging has an important role in the assessment of patients with acute-onset chest pain. In patients with suspected acute coronary syndrome (ACS), cardiac imaging offers incremental value over routine clinical assessment, the electrocardiogram, and blood biomarkers of myocardial injury, to confirm or refute the diagnosis of coronary artery disease and to assess future cardiovascular risk. This Review covers the current guidelines and clinical use of the common noninvasive imaging techniques, including echocardiography and stress echocardiography, computed tomography coronary angiography, myocardial perfusion scintigraphy, positron emission tomography, and cardiovascular magnetic resonance imaging, in patients with suspected ACS, and provides an update on the developments in noninvasive imaging techniques in the past 5 years.

Chest pain: coronary CT in the ER

Cardiac CT has developed into a robust clinical tool during the past 15 years. Of the fields in which the potential of cardiac CT has raised more interest is chest pain in acute settings. In fact, the possibility to exclude with high reliability obstructive coronary artery disease (CAD) in patients at low-to-intermediate risk is of great interest both from the clinical standpoint and from the management standpoint. Several other modalities, with or without imaging, have been used during the past decades in the settings of new onset chest pain or in acute chest pain for both diagnostic and prognostic assessment of CAD. Each one has advantages and disadvantages. Most imaging modalities also focus on inducible ischaemia to guide referral to invasive coronary angiography. The advent of cardiac CT has introduced a new practice diagnostic paradigm, being the most accurate non-invasive method for identification and exclusion of CAD. Furthermore, the detection of subclinical CAD and plaque imaging offer the opportunity to improve risk stratification. Moreover, recent advances of the latest generation CT scanners allow combining both anatomical and functional imaging by stress myocardial perfusion. The role of cardiac CT in acute settings is already important and will become progressively more important in the coming years.

The use of echocardiography in acute cardiovascular care: Recommendations of the European Association of Cardiovascular Imaging and the Acute Cardiovascular Care Association

Echocardiography is one of the most powerful diagnostic and monitoring tools available to the modern emergency/critical care practitioner. Currently, there is a lack of specific European Association of Cardiovascular Imaging/Acute Cardiovascular Care Association recommendations for the use of echocardiography in acute cardiovascular care. In this document, we describe the practical applications of echocardiography in patients with acute cardiac conditions, in particular with acute chest pain, acute heart failure, suspected cardiac tamponade, complications of myocardial infarction, acute valvular heart disease including endocarditis, acute disease of the ascending aorta and post-intervention complications. Specific issues regarding echocardiography in other acute cardiovascular care scenarios are also described.

The use of echocardiography in acute cardiovascular care: recommendations of the European Association of Cardiovascular Imaging and the Acute Cardiovascular Care Association

Echocardiography is one of the most powerful diagnostic and monitoring tools available to the modern emergency/ critical care practitioner. Currently, there is a lack of specific European Association of Cardiovascular Imaging/Acute Cardiovascular Care Association recommendations for the use of echocardiography in acute cardiovascular care. In this document, we describe the practical applications of echocardiography in patients with acute cardiac conditions, in particular with acute chest pain, acute heart failure, suspected cardiac tamponade, complications of myocardial infarction, acute valvular heart disease including endocarditis, acute disease of the ascending aorta and post-intervention complications. Specific issues regarding echocardiography in other acute cardiovascular care scenarios are also described.

Rationale and design of a randomized trial comparing initial stress echocardiography versus coronary CT angiography in low-to-intermediate risk emergency department patients with chest pain

BACKGROUND

Comparative effectiveness research (CER) has become a major focus of cardiovascular disease investigation to optimize diagnosis and treatment paradigms and decrease healthcare expenditures. Acute chest pain is a highly prevalent reason for evaluation in the Emergency Department (ED) that results in hospital admission for many patients and excess expense. Improvement in noninvasive diagnostic algorithms can potentially reduce unnecessary admissions.

OBJECTIVE

To compare the performance of treadmill stress echocardiography (SE) and coronary computed tomography angiography (CTA) in ED chest pain patients with low-to-intermediate risk of significant coronary artery disease.

DESIGN

This is a single-center, randomized controlled trial (RCT) comparing SE and CTA head-to-head as the initial noninvasive imaging modality. The primary outcome measured is the incidence of hospitalization. The study is powered to detect a reduction in admissions from 28% to 15% with a sample size of 400. Secondary outcomes include length of stay in the ED/hospital and estimated cost of care. Safety outcomes include subsequent visits to the ED and hospitalizations, as well as major adverse cardiovascular events at 30 days and 1 year. Patients who do not meet study criteria or do not consent for randomization are offered entry into an observational registry.

CONCLUSIONS

This RCT will add to our understanding of the roles of different imaging modalities in triaging patients with suspected angina. It will increase the CER evidence base comparing SE and CTA and provide insight into potential benefits and limitations of appropriate use of treadmill SE in the ED.

Role of imaging for acute chest pain syndromes

Acute chest pain suggestive of ischemic cardiac origin, with a normal or nondiagnostic electrocardiogram and negative initial cardiac markers for myocardial necrosis represent a significant diagnostic dilemma for clinicians. Multiple imaging modalities play a pivotal role in early diagnosis and safe discharge of these patients. In this review, we compare the current imaging modalities available for these patients including their diagnostic accuracy, feasibility, and cost effectiveness. Acute rest myocardial perfusion imaging significantly improves the clinical outcome in these patients and reduces the overall cost when incorporated into the decision making pathway. The choice of imaging modality recommended should be based on local institutional expertise and the overall clinical presentation. The imaging modality with high diagnostic accuracy and negative predictive value will provide for precise risk stratification which is important to clinical decision making, including patients who require admission to the hospital and those who can be safely discharged.

Stress echocardiography in the ED: diagnostic performance in high-risk subgroups

PURPOSE

To assess stress-echo (SE) diagnostic performance in patients presenting to the emergency department (ED) with spontaneous chest pain, especially in subgroups in which exercise ECG diagnostic performance has been questioned (women, elderly, history of coronary artery disease).

METHODS

Between June 2008 and May 2011, 474 patients with an episode of spontaneous chest pain, non-diagnostic electrocardiogram and negative cardiac necrosis markers underwent SE. Patients with inducible ischemia (Isch) were asked to undergo coronary angiography. Patients with negative SE were discharged and contacted by telephone at least 6 months after discharge, to ascertain the occurrence of new cardiac events.

MAIN FINDINGS

Exercise stress-echo (ESE) was employed in 270 patients and dobutamine (DSE) in 218 (including 14 with inconclusive ESE); a diagnosis of coronary artery disease (CAD) was confirmed or excluded in 434 (92%) patients. SE was negative for Isch in 318 patients (206 ESE and 112 DSE) and positive in 132. During follow-up, patients with negative SE had 4 cardiac events. SE showed: sensitivity 90%, specificity 92%, positive predictive value 78% and negative predictive value 97%. Sensitivity was comparable between patients aged < or ≥70 years (84 vs 94%) and between gender (89 vs 96%), but lower in patients with known CAD (88 vs 94%, P < .05); specificity was comparable regardless of age (94 vs 99%) and presence of CAD (97 vs 91%), but was lower among women (87 vs 96%, P < .05).

CONCLUSIONS

SE had a very good diagnostic performance in ED patients with suspected Isch, both overall and in selected high-risk groups.

Use of contrast echocardiography in intensive care and at the emergency room

Bedside echocardiography in emergency room (ER) or in intensive care unit (ICU) is an important tool for managing critically ill patients, to obtain a timely accurate diagnosis and to immediately stratify the risk to the patient’s life. It may also render invasive monitoring unnecessary. In these patients, contrast echocardiography may improve quality of imaging and also may provide additional information, especially regarding myocardial perfusion in those with suspected coronary artery disease. This article focuses on the principle of contrast echocardiography and the clinical information that can be obtained according to the most frequent presentations in ER and ICU.

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.

Accuracy and Cost Comparison of Ultrasound Versus Alternative Imaging Modalities, Including CT, MR, PET, and Angiography

Ultrasound (US) has become widely used in clinical medicine for the diagnosis of a variety of disease processes. The unique ability of US to provide accurate information through an efficacious, painless, portable, and nonionizing method has expanded its role and application in diverse medical settings. Given the current economic environment and the related interest in creating the greatest value for health care expenditures, US has been evaluated to compare its clinical accuracy/efficacy and cost-effectiveness versus other imaging modalities. The following literature review reports the results of research studies aimed at comparing the accuracy/efficacy and cost of US versus alternative imaging modalities, including magnetic resonance imaging, computed tomography, contrast angiography, and single-photon emission computed tomography.

Predictive value of normal dobutamine stress echocardiogram in patients with low-risk acute chest pain

Dobutamine stress echocardiography (DSE) has been proposed as a tool for risk stratification of patients with acute chest pain (ACP). In this single-center study, we evaluated the negative predictive value of DSE in 178 patients who presented with low-risk ACP (normal or inconclusive electrocardiogram and negative markers of myocardial damage) and were discharged following a maximal DSE that did not reveal ischemia. During the follow-up (median 321 days), 2 of the 178 patients were admitted with an acute coronary syndrome and were diagnosed with obstructive coronary artery disease at angiography. In the time frame of the study, the negative predictive value of a normal and maximal DSE for an adverse cardiac event was 98.9% (95% CI: 96.0-99.8%). Thus, a normal DSE has a high negative predictive value and comprises a safe and effective tool for early risk stratification of patients who present with acute chest pain of low risk.

Effect on quality of life of different accelerated diagnostic protocols for management of patients presenting to the emergency department with acute chest pain

This study assessed the effects on quality of life (QoL) of dobutamine-atropine stress echocardiography (DASE) and electrocardiogram exercise testing (EET) accelerated diagnostic protocols for early stratification of low-risk patients with acute chest pain (ACP). A total of 290 patients with ACP, a nondiagnostic electrocardiogram, and negative biomarkers were randomly assigned to an accelerated diagnostic protocol (DASE, n = 110, or EET, n = 89) or usual care (n = 91) and followed up for 2 months. QoL was assessed at discharge and 2-month follow-up using the Nottingham Health Profile questionnaire. Baseline and 2-month follow-up answers to the Nottingham Health Profile questionnaire were available for 207 patients (71%; 55 in the usual-care, 77 in the DASE, and 75 in the ETT arm). At predischarge, patients in the usual-care arm reported higher impairment in the physical mobility and pain dimensions compared with the DASE and EET arms (p = 0.019 and p = 0.023, respectively). At 2-month follow-up, QoL improved in all groups; however, patients in the usual-care arm had significantly worse scores than patients managed using accelerated diagnostic protocols in the physical mobility, pain, social isolation, emotional reactions, and energy level dimensions (p = 0.014, p = 0.002, p = 0.04, p = 0.01, and p = 0.003, respectively). In conclusion, low-risk patients with ACP had non-negligible impairment of QoL in the acute phase. Emergency department ADPs with early DASE and EET reduced QoL impairment at both baseline and 2-month follow-up.

Cost-efficiency of myocardial contrast echocardiography in patients presenting to the emergency department with chest pain of suspected cardiac origin and a nondiagnostic electrocardiogram

Assessment of patients presenting to the emergency department (ED) with suspected cardiac chest pain and a nondiagnostic electrocardiogram (ECG) is lengthy and costly. It was hypothesized that myocardial contrast echocardiography (MCE) can be cost-efficient in such patients by detecting those with chest pain that is noncardiac in nature. Accordingly, cost-efficiency was evaluated in 957 patients presenting to the ED with suspected cardiac chest pain, but no ST-segment elevation on the ECG, who underwent MCE. Economic outcome calculations were based on costs estimated from national average Medicare charges adjusted by a cost-charge ratio. Based on routine clinical criteria, 641 patients (67%) were admitted to the hospital, whereas 316 (33%) were discharged directly from the ED. The average cost per patient using routine evaluation was $5,000. Patients with normal MCE results (n = 523) had a very low primary event rate (death, acute myocardial infarction) of 0.6% within 24 hours after presentation, making it relatively safe to discharge patients directly from the ED with a normal MCE result. Hence, if MCE had been used for decision making, 523 patients (55%) would have been discharged directly from the ED and 434 (45%) would have been admitted to the hospital. Preventing unnecessary admissions and tests would have saved an average of $900 per patient, in addition to reducing their ED stay. In conclusion, by excluding cardiac causes in patients presenting to the ED with chest pain and a nondiagnostic ECG, MCE can prevent unnecessary admissions and downstream resource utilization, making it a cost-efficient tool in the evaluation of these patients.

Diagnostic uncertainty and costs associated with current emergency department evaluation of low risk chest pain

INTRODUCTION

Of all stress tests done in low risk Emergency Department observation units (OU), a small, but significant number may be reported as positive or indeterminate. The objective of this study is to quantify the prevalence and costs associated with positive and indeterminate stress tests that result in negative cardiac catheterization.

METHODS

Retrospective observational cohort study over 9 months. All patients undergoing the chest pain protocol who got cardiac stress testing in the OU were eligible for inclusion. Cost data were derived from an institutional activity-based cost system utilizing actual costs. Chart review was completed on all patients with positive and indeterminate stress tests and a randomly chosen sample of those with negative stress tests.

RESULTS

Of the 1194 patients who met the inclusion criteria, 1084 (90.8%) had a negative stress test. Sixty-two (5.2%) had a positive stress test, and 48 (4.0%) had an indeterminate stress test. Of all 59 patients who underwent catheterization, 41 (69.5%) were negative cardiac catheterizations. The prevalence among all OU stress test patients of positive or indeterminate stress tests with subsequent negative cardiac catheterization was 41/1194 (3.4%; 95% CI 2.5%-4.6%). The prevalence of significant coronary artery disease at cardiac catheterization was 18/1194 (1.5%; 95% CI 1.0%-2.4%). Patients with a positive or indeterminate stress test who had a negative catheterization incurred increased OU costs ($1385 vs. $1,039, P = 0.012), total costs ($7298 vs. $1562, P < 0.001) and length of inpatient stay (1.83 days vs. 0.00 days) when compared with those who had a negative stress test.

CONCLUSION

The probability of going to the OU and having a positive or indeterminate stress test resulting in a subsequent negative catheterization was double the probability of having a stress test result in catheterization that detected significant coronary artery disease. These patients incurred 5 times the total cost when compared with those patients with negative stress testing. Further investigation is warranted to determine alternative risk stratification methods for these low risk chest pain patients with positive stress tests.

Sixty-four-slice computed tomography of the coronary arteries: cost-effectiveness analysis of patients presenting to the emergency department with low-risk chest pain

OBJECTIVES

The aim was to use a computer model to estimate the cost-effectiveness of 64-slice multidetector computed tomography (MDCT) of the coronary arteries in the emergency department (ED) compared to an observation unit (OU) stay plus stress electrocardiogram (ECG) or stress echocardiography for the evaluation of low-risk chest pain patients presenting to the ED.

METHODS

A decision analytic model was developed to compare health outcomes and costs that result from three different risk stratification strategies for low-risk chest pain patients in the ED: stress ECG testing after OU care, stress echocardiography after OU care, and MDCT with no OU care. Three patient populations were modeled with the prevalence of symptomatic coronary artery disease (CAD) being very low risk, 2%; low risk, 6% (base case); and moderate risk, 10%. Outcomes were measured as quality-adjusted life years (QALYs). Incremental cost-effectiveness ratios (ICERs), the ratio of change in costs of one test over another to the change in QALY, were calculated for comparisons between each strategy. Sensitivity analyses were conducted to test the robustness of the results to assumptions regarding the characteristics of the risk stratification strategies, costs, utility weights, and likelihood of events.

RESULTS

In the base case, the mean (+/- standard deviation [SD]) costs and QALYs for each risk stratification strategy were MDCT arm $2,684 (+/- $1,773 to $4,418) and 24.69 (+/- 24.54 to 24.76) QALYs, stress echocardiography arm $3,265 (+/- $2,383 to $4,836) and 24.63 (+/- 24.28 to 24.74) QALYs, and stress ECG arm $3,461 (+/- $2,533 to $4,996) and 24.59 (+/- 24.21 to 24.75) QALYs. The MDCT dominated (less costly and more effective) both OU plus stress echocardiography and OU plus stress ECG. This resulted in an ICER where the MDCT arm dominated the stress echocardiography arm (95% confidence interval [CI] = dominant to $29,738) and where MDCT dominated the ECG arm (95% CI = dominant to $7,332). The MDCT risk stratification arm also dominated stress echocardiography and stress ECG in the 2 and 10% prevalence scenarios, which demonstrated the same ICER trends as the 6% prevalence CAD base case. The thresholds where the MDCT arm remained a cost-saving strategy compared to the other risk stratification strategies were cost of MDCT, < $2,097; cost of OU care, > $1,092; prevalence of CAD, < 70%; MDCT specificity, > 65%; and a MDCT indeterminate rate, < 30%.

CONCLUSIONS

In this computer-based model analysis, the MDCT risk stratification strategy is less costly and more effective than both OU-based stress echocardiography and stress ECG risk stratification strategies in chest pain patients presenting to the ED with low to moderate prevalence of CAD.