An Evaluation of Technologies for Identifying Acute Cardiac Ischemia in the Emergency Department: Executive Summary of a National Heart Attack Alert Program Working Group Report,☆☆,

https://doi.org/10.1016/S0196-0644(97)70297-XGet rights and content

Abstract

[Selker HP, Zalenski RJ, Antman EM, Aufderheide TP, Bernard SA, Bonow RO, Gibler WB, Hagen MD, Johnson P, Lau J, McNutt RA, Ornato J, Schwartz JS, Scott JD, Tunick PA, Weaver WD: An evaluation of technologies for identifying acute cardiac ischemia in the emergency department: Executive Summary of a National Heart Attack Alert Program Working Group report. Ann Emerg Med January 1997;29:1-12.]

Section snippets

INTRODUCTION AND METHODS

As the most common cause of death in this country, acute myocardial infarction (AMI) has deservedly been the subject of substantial efforts of clinicians, scientists, government and other agencies, and the public in efforts to reduce its devastating impact. Although very significant progress continues to be made, the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) recognized the need for a concerted and coordinated effort to reduce mortality and

WORKING GROUP PROCESS AND METHODS

To accomplish this review, a formal process of review and evaluation of the scientific literature related to these technologies was undertaken, based on Medline and related electronic literature searches and supplemented by the panelists' knowledge of the literature and ongoing research. All relevant English-language literature on each technology was reviewed, summarized, analyzed, and reported on independently by three panel members in a process analogous to an NIH Study Section.

For each

STANDARD ECG

The ECG represents a safe, readily available, and inexpensive technology for assessing patients with acute chest pain and is central to its evaluation. However, the ECG suffers from imperfect sensitivity and specificity for ACI. When interpreted using liberal criteria, the ECG operates with relatively high (but not perfect) sensitivity for AMI, at the cost of low specificity. Conversely, when interpreted using stringent criteria for AMI, sensitivity drops to levels around 50% or below.

The ECG

PREHOSPITAL ECG

Studies to date demonstrate that prehospital 12-lead ECG technology is feasible and clinically practical and probably could be implemented in most established urban paramedic systems. Prehospital identification of thrombolysis candidates through the use of prehospital 12-lead electrocardiography has been shown in almost every study to significantly reduce hospital-based time to treatment. This time savings is perceived as beneficial but has not, by itself, demonstrated a reduction in mortality.

CONTINUOUS 12-LEAD ECG

There have been no well-designed large randomized prospective ED or CCU studies evaluating this technology. Cost-benefit analysis of this technology has not been accomplished. Although ED ST-segment monitoring holds the potential to detect silent myocardial ischemia and infarction, reduce missed ischemic diagnoses, and provide the earliest evidence for coronary occlusion in patients presenting with preinfarction angina, larger prospective studies are required to make this assessment.

The results

NONSTANDARD ECG LEADS AND BODY-SURFACE MAPPING

Sampling right ventricular leads is clinically practical, uses the universally available 12-lead ECG, and appears to increase the sensitivity and specificity for detection of right ventricular infarction (a strong, independent predictor of major complications and in-hospital mortality in patients with inferior AMI). Such leads have the potential to improve severity classification of AMIs, help refine the process of risk-benefit assessment for emergency interventions, possibly provide an

ECG EXERCISE STRESS TEST

Currently there are limited data on the impact of ECG exercise stress testing in the ED. Where the risk of coronary artery disease is low to moderate, the expedited ECG stress test may offer the benefit of an expedited workup and may reduce hospital admissions for chest pain. Observation status, where the patient is observed pending definitive testing, may offer a similar benefit. However, ECG exercise stress testing in the ED cannot be recommended in the absence of additional data

ORIGINAL ACI PREDICTIVE INSTRUMENT

The original ACI predictive instrument uses readily available clinical and ECG data to compute a probability of ACI. Its diagnostic performance and clinical impact have been well demonstrated in large prospective clinical trials1, 2, which have shown it to be safe and effective in improving ED triage of patients with possible ACI in a wide range of hospitals. Although appropriate for general clinical use, it has not been widely adopted in EDs, possibly because of the need for a hand-held

ACUTE CARDIAC ISCHEMIA TIME INSENSITIVE PREDICTIVE INSTRUMENT (ACI-TIPI)

The ACI-TIPI, like the original ACI predictive instrument, provides the ED physician with the 0% to 100% probability that a given patient truly has ACI to supplement the ED triage decision. Its diagnostic performance has been tested in large studies that included ED3, 4 and EMS5 patients and has been demonstrated to be diagnostically equivalent to the earlier version3, except for a slightly higher sensitivity for AMI. Thus, clinical use should be comparable to the original ACI predictive

GOLDMAN CHEST PAIN PROTOCOL

The Goldman computer-based chest pain protocol was developed with the use of a sound methodology. The fact that it was validated in a large population that included two university and four community hospitals, with at least two of the hospitals having racially diverse populations, supports its potential utility in a diverse patient population. As the protocol currently stands, its greatest potential benefit would likely be in improving physicians' specificity for AMI and avoidance of triage to

OTHER COMPUTER-BASED DECISION AIDS

These computer-based decision aids provide examples of a variety of ways to identify patients for CCU admission but have a number of major limitations, especially that they predict AMI rather than ACI and have not yet been demonstrated to be safe and effective in actual use. In addition, there are some concerns about the generalizability and transportability of some of their input variables and, for the neural network model of Baxt8, concerns about the “black box” and lack of publication of the

CREATINE KINASE

Creatine kinase (CK) and CK isoenzyme-cardiac muscle subunit (CK-MB) measurements are traditionally obtained early in the ED course of a patient admitted to the hospital for suspected AMI or ACI. The utility of the assay in the ED as a one-time test is limited because levels do not significantly increase until 4 to 6 hours after the onset of AMI. Mass measurements of CK-MB, compared with the older activity analysis, have improved sensitivity and specificity. Improved sensitivity may also be

OTHER BIOCHEMICAL TESTS

Myoglobin, an early marker of AMI, and the cardiac troponins T and I, which are specific for myocyte damage and are late markers, hold promise to improve the identification of patients with AMI and minor myocardial injury. However, the use of new biochemical markers in the ED as a routine measure to improve either the initial triage or therapy of patients with AMI is currently unproven. Although this information may be useful in those hospitals attempting to triage patients between ED holding

ECHOCARDIAGRAM

Although echocardiography in the ED showed initial promise, it is labor-intensive and insensitive for distinguishing new from old ischemia. Its use in the absence of chest pain appears to be more accurate in a single study with low numbers for unclear reasons. It can be recommended as an adjunctive test if readily available during atypical chest pain; there are insufficient data demonstrating that it can effectively triage patients in large clinical settings.

Echocardiography is a generally

THALLIUM SCANNING

The use of radionuclide imaging for the diagnosis of ACI/AMI in the ED should be restricted to specialized and limited situations in which the clinical triad of history, ECG changes, and enzymatic/laboratory measurements is not available or is unreliable. Such imaging may be helpful, for example, in patients with equivocal chest pain histories and nondiagnostic ECG findings. Thallium-201 is an excellent perfusion tracer, but the available data indicate relatively poor diagnostic accuracy in the

SESTAMIBI AND OTHER TECHNETIUM-99m PERFUSION AGENTS

The use of radionuclide imaging for the diagnosis of ACI/ AMI in the ED should be restricted to specific and limited conditions in which the clinical triad of history, ECG changes, and enzymatic/laboratory measurements is not available or is unreliable. Such imaging may be helpful, for example, in patients with equivocal chest pain histories and nondiagnostic ECG findings. The applicability of this imaging modality depends primarily on logistical issues. Technetium-99m-sestamibi (99m

CONCLUSIONS AND RECOMMENDATIONS

Summary of clinical recommendations based on demonstrated diagnostic performance and clinical impact Recommendations regarding the use of a technology should be based on both ED diagnostic performance and clinical impact data obtained in high-quality or substantial studies. Of the various diagnostic technologies evaluated in the 14 sections, however, only five met this highly desirable standard of evaluation.

The original ACI predictive instrument was found to be excellent for diagnostic

RECOMMENDATIONS FOR RESEARCH

Although the primary purpose of this report is to provide clinical recommendations, Table 1 (see p 10) makes it clear that there is currently a great lack of research results related to the diagnostic performance and especially the clinical impact of these most important technologies for the emergency evaluation of the most common cause of death in our country. Further diagnostic trials addressing both their accuracy and impact are critical to the NHAAP mission to improve rapidity and

References (15)

There are more references available in the full text version of this article.

Cited by (66)

  • Acute Coronary Syndromes. From the Emergency Department to the Cardiac Care Unit

    2012, Cardiology Clinics
    Citation Excerpt :

    Although ECGs are helpful in the diagnosis and management of ACS, sensitivity and specificity can vary widely based on the criteria used for interpretation and the selected patient population. One study reported that specificity can vary from 21% to 95% and sensitivity from 61% to 99% based on the stringency of criteria used to evaluate ACS.24 Thus the implications of ECG findings must be interpreted in a Bayesian fashion, accounting for the likelihood of ACS given all data applicable to the patient.

  • A Predictive Instrument Using Contrast Echocardiography in Patients Presenting to the Emergency Department with Chest Pain and without ST-Segment Elevation

    2010, Journal of the American Society of Echocardiography
    Citation Excerpt :

    The inability to rapidly diagnose and risk stratify patients makes their triage to an adequate location for care difficult (hospital ward vs step-down unit vs coronary care unit vs discharge from the ED) or to determine those who could benefit the most from aggressive therapy. Many reports have focused on only a single variable (eg, ECG abnormalities or elevated serum cardiac markers),13,14,19-21 and subsequent reports have found them to be unreliable. Despite major advances in imaging technology and many reports indicating the benefits of MP imaging (whether echocardiography5-9 or single photon emission computed tomography22-24) in such patients, their use is limited only to institutions where there is a strong collaboration between the ED and cardiovascular medicine.

  • Chest pain: A clinical assessment

    2006, Radiologic Clinics of North America
  • Acute coronary syndromes in the emergency department: Diagnostic characteristics, tests, and challenges

    2005, Cardiology Clinics
    Citation Excerpt :

    The investigators' failure to find association between an S3 gallop rhythm and ACSs at final diagnosis is surprising, but it may have to do with a failure to document this finding consistently in the medical record on the part of the physicians in the EDs at study sites. A complete summary of evidence related to the diagnostic usefulness of the standard ECG was recently published [20,57], and this background will not be repeated in this article. However, the National Heart Attack Alert Program (NHAAP) Working Group on “Evaluation of Technologies for Identifying Acute Cardiac Syndrome” [57] found that most studies evaluate the accuracy of the technologies and only a few evaluate the clinical impact of routine use.

View all citing articles on Scopus

From the National Heart Attack Alert Program, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.

☆☆

Address for reprints: Mary M Hand, MSPH, RN, National Heart Attack Alert Program, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 31, Room 4A18, 31 Center Drive, MSC 2480, Bethesda, Maryland 20892-2480, 301-594-2726, Fax 301-402-1051, E-mail [email protected]

Reprint no. 47/1/78527

View full text