This is the current release of the guideline.

This guideline updates a previous version: Stanford W, Yucel EK, Khan A, Atalay MK, Haramati LB, Ho VB, Mammen L, Rozenshtein A, Rybicki FJ, Schoepf UJ, Stein B, Woodard PK, Jaff M, Expert Panel on Cardiac Imaging. ACR Appropriateness Criteria® acute chest pain--low probability of coronary artery disease. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 4 p.

Acute nonspecific chest pain with low probability of coronary artery disease (CAD)

To evaluate the appropriateness of initial radiologic examinations for patients with acute nonspecific chest pain with low probability of coronary artery disease (CAD)

Patients with acute nonspecific chest pain with low probability of coronary artery disease (CAD)

Note: Patients with signs and/or symptoms of acute coronary syndrome (ACS) along with diagnostic ST-segment changes, and elevated cardiac enzymes suggesting myocardial infarction are not included in this discussion as the evaluation and treatment algorithms have been well defined in the Scientific Statements and Practice Guidelines of the American Heart Association and in the American College of Radiology (ACR) Appropriateness Criteria® topic "Chest Pain, Suggestive of Acute Coronary Syndrome."

Utility of radiologic examinations in differential diagnosis

Literature Search Procedure

The Medline literature search is based on keywords provided by the topic author. The two general classes of keywords are those related to the condition (e.g., ankle pain, fever) and those that describe the diagnostic or therapeutic intervention of interest (e.g., mammography, MRI).

The search terms and parameters are manipulated to produce the most relevant, current evidence to address the American College of Radiology Appropriateness Criteria (ACR AC) topic being reviewed or developed. Combining the clinical conditions and diagnostic modalities or therapeutic procedures narrows the search to be relevant to the topic. Exploding the term "diagnostic imaging" captures relevant results for diagnostic topics.

The following criteria/limits are used in the searches.

1. Articles that have abstracts available and are concerned with humans.
2. Restrict the search to the year prior to the last topic update or in some cases the author of the topic may specify which year range to use in the search. For new topics, the year range is restricted to the last 5 years unless the topic author provides other instructions.
3. May restrict the search to Adults only or Pediatrics only.
4. Articles consisting of only summaries or case reports are often excluded from final results.

The search strategy may be revised to improve the output as needed.

The total number of source documents identified as the result of the literature search is not known.

Strength of Evidence Key

Category 1 - The conclusions of the study are valid and strongly supported by study design, analysis and results.

Category 2 - The conclusions of the study are likely valid, but study design does not permit certainty.

Category 3 - The conclusions of the study may be valid but the evidence supporting the conclusions is inconclusive or equivocal.

Category 4 - The conclusions of the study may not be valid because the evidence may not be reliable given the study design or analysis.

The topic author drafts or revises the narrative text summarizing the evidence found in the literature. American College of Radiology (ACR) staff draft an evidence table based on the analysis of the selected literature. These tables rate the strength of the evidence for all articles included in the narrative text.

The expert panel reviews the narrative text, evidence table, and the supporting literature for each of the topic-variant combinations and assigns an appropriateness rating for each procedure listed in the table. Each individual panel member forms his/her own opinion based on his/her interpretation of the available evidence.

More information about the evidence table development process can be found in the American College of Radiology (ACR) Appropriateness Criteria® Evidence Table Development document (see the "Availability of Companion Documents" field).

Modified Delphi Technique

The appropriateness ratings for each of the procedures included in the Appropriateness Criteria topics are determined using a modified Delphi methodology. A series of surveys are conducted to elicit each panelist's expert interpretation of the evidence, based on the available data, regarding the appropriateness of an imaging or therapeutic procedure for a specific clinical scenario. American College of Radiology (ACR) staff distributes surveys to the panelists along with the evidence table and narrative. Each panelist interprets the available evidence and rates each procedure. The surveys are completed by panelists without consulting other panelists. The ratings are a scale between 1 and 9, which is further divided into three categories: 1, 2, or 3 is defined as "usually not appropriate"; 4, 5, or 6 is defined as "may be appropriate"; and 7, 8, or 9 is defined as "usually appropriate." Each panel member assigns one rating for each procedure per survey round. The surveys are collected and the results are tabulated, de-identified and redistributed after each round. A maximum of three rounds are conducted. The modified Delphi technique enables each panelist to express individual interpretations of the evidence and his or her expert opinion without excessive bias from fellow panelists in a simple, standardized and economical process.

Consensus among the panel members must be achieved to determine the final rating for each procedure. Consensus is defined as eighty percent (80%) agreement within a rating category. The final rating is determined by the median of all the ratings once consensus has been reached. Up to three rating rounds are conducted to achieve consensus.

If consensus is not reached, the panel is convened by conference call. The strengths and weaknesses of each imaging procedure that has not reached consensus are discussed and a final rating is proposed. If the panelists on the call agree, the rating is accepted as the panel's consensus. The document is circulated to all the panelists to make the final determination. If consensus cannot be reached on the call or when the document is circulated, "No consensus" appears in the rating column and the reasons for this decision are added to the comment sections.

Not applicable

A formal cost analysis was not performed and published cost analyses were not reviewed.

Criteria developed by the Expert Panels are reviewed by the American College of Radiology (ACR) Committee on Appropriateness Criteria.

ACR Appropriateness Criteria®

Clinical Condition: Acute Nonspecific Chest Pain -- Low Probability of Coronary Artery Disease

Radiologic Procedure	Rating	Comments	RRL*
X-ray chest	9
CTA coronary arteries with contrast	7
CTA coronary arteries with contrast with advanced low dose techniques	7
CTA chest (noncoronary) with contrast	7
US echocardiography transthoracic resting	7		O
SPECT MPI rest and stress	6
Tc-99m V/Q scan lung	5
MRA aorta without and with contrast	5	See comments regarding contrast in the text below under "Anticipated Exceptions."	O
X-ray rib views	5
MRA chest (noncoronary) without and with contrast	5	See comments regarding contrast in the text below under "Anticipated Exceptions."	O
MRA aorta without contrast	4		O
MRA chest (noncoronary) without contrast	4		O
X-ray barium swallow and upper GI series	4
X-ray thoracic spine	4
US abdomen	4		O
MRI heart with or without stress without and with contrast	3		O
MRA pulmonary arteries without and with contrast	3		O
MRA coronary arteries without contrast	3		O
MRA coronary arteries without and with contrast	3		O
US echocardiography transthoracic stress	3		O
US echocardiography transesophageal	2		O
MRI heart with or without stress without contrast	2		O
MRA pulmonary arteries without contrast	2		O
Coronary angiography with or without ventriculography	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the table are listed at the end of the "Major Recommendations" field.

Summary of Literature Review

Patients who present to the emergency department (ED) with acute chest pain are stratified according to their probability of developing acute coronary syndrome (ACS) as follows: very low (<1%), low (1%-4%), intermediate (4%-8%), or high (>8%) probability. This document outlines the usefulness of available diagnostic imaging for those patients without known coronary artery disease (CAD) and at low probability for having CAD who do not present with classic ACS signs, symptoms, or electrocardiogram (ECG) abnormalities, but rather with nonspecific chest pain leading to a differential diagnosis, including pulmonary, gastrointestinal (GI), or musculoskeletal pathologies. In contrast, patients presenting to the ED with signs and/or symptoms of ACS along with diagnostic ST-segment changes, and elevated cardiac enzymes suggesting myocardial infarction are not included in this discussion as the evaluation and treatment algorithms have been well defined in the Scientific Statements and Practice Guidelines of the American Heart Association and in the National Guideline Clearinghouse (NGC) summary, ACR Appropriateness Criteria® chest pain, suggestive of acute coronary syndrome.

The following imaging modalities are available in evaluating patients presenting to the ED with low probability of CAD: chest radiography, multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), ventilation/perfusion (V/Q) scans, cardiac perfusion scintigraphy, transesophageal and transthoracic echocardiography, positron emission tomography (PET), spine and rib radiography, barium esophageal and upper GI studies, and abdominal ultrasound.

Chest Radiography

The chest radiograph is the recommended initial imaging study. Chest radiographs can help identify potential sources of previously undifferentiated chest pain such as pneumothorax, pneumomediastinum, fractured ribs, acute and chronic infections, and malignancies. Other conditions producing chest pain, such as pulmonary emboli (PE), may be suspected from the chest radiograph, but the overall sensitivities are low. Thoracic calcifications, if present, may indicate pericardial disease, ventricular aneurysm, intracardiac thrombi, or aortic disease. While chest radiographs are often normal for the presence of PE, the presence of a Hampton hump, Westermark sign, or pulmonary artery enlargement may suggest PE. Mediastinal air may indicate a ruptured viscus or subpleural bleb or other acute pathology.

Multidetector Computed Tomography

MDCT has excellent accuracy in demonstrating noncardiac causes of chest pain, including pneumothorax, pneumonia, malignancies, pulmonary airspace abnormalities, and interstitial lung disease. Pericardial effusions, thickening, and/or calcifications are seen far more readily than with radiographs alone. In the setting of undifferentiated chest pain, CT angiography (CTA) with its high sensitivity and specificity can be considered the modality of choice to diagnose suspected PE and/or aortic pathology such as aortic dissection (AD) or aneurysm. Both prospective (mean radiation exposure <5 mSv) and retrospective (mean radiation exposure <12 mSv) ECG-synchronized cardiac CT permits comprehensive assessment of the presence and extent of CAD. Most importantly, in this low-risk population, cardiac CTA has nearly perfect negative predictive value to rule out significant CAD. When coronary CTA is performed with retrospective ECG gating, additional assessment of wall motion adds significant incremental value. MDCT is also the primary method for diagnosing coronary anomalies, a rare cause of acute chest pain.

Cardiac CT can also detect other symptom-producing pathologies such as ventricular aneurysms and cardiac thrombi or tumors. Significant findings such as PE or AD appear to be rare in patients with undifferentiated chest pain, probably because of the low probability for any disease. However, pulmonary nodules are detected in a significant number of patients. With advanced CT technology, it is possible to perform a single-phase triple rule-out examination allowing comprehensive assessment of CAD, AD, and PE. However, its efficiency or effectiveness has not been demonstrated.

Recent advances in cardiac CT imaging technology allow for further reduction of the radiation dose from cardiac CTA; available new dose-reducing techniques include prospective triggering, adaptive statistical iterative reconstruction, and high-pitch spiral acquisition. These new lower-dose techniques are the appropriate choice in properly selected patients who have a low heart rate (<65 beats per minute [bpm]) and are in sinus rhythm.

Transthoracic and Transesophageal Echocardiography

Transthoracic and transesophageal echocardiography with or without pharmacologic stress are frequently used to define abnormalities of ventricular wall motion as an indicator of cardiac disease. In addition, echocardiography can readily demonstrate pericardial effusion, valve dysfunction, and cardiac thrombus. Aortic pathology can be identified, but the findings of intramural hematoma, dissection, pulmonary embolus, and aneurysm are better seen with MDCT or MRI. Most importantly, transthoracic echocardiography without stress is a low-risk screening examination with high negative predictive value for ACS.

Magnetic Resonance Imaging

Magnetic resonance angiography (MRA) can be performed with either noncontrast (e.g., time-of-flight, balanced steady-state free precession, phase-contrast, black-blood) or contrast-enhanced (e.g., 3D arterial-phase fast gradient-echo) protocols that are useful in identifying vascular pathology. These techniques can be used to accurately identify aortic pathology and in specific scenarios may also be used to evaluate for pulmonary artery pathology. MRA is typically more time-consuming and less available in the ED setting, but it is an important alternative noninvasive imaging strategy in patients with a contraindication to CTA. Cardiac MRI has not been well studied in low-risk undifferentiated chest pain populations and is uncommonly used in the emergency setting because of the relatively long scan times. The benefits and role of cardiac MRI, both with and without pharmacologic stress, in this population remain uncertain and have yet to be subjected to large controlled trials.

Radiography of the Ribs, Cervical Spine, or Thoracic Spine

Rib or spine radiographs are indicated in patients with a clinical suspicion of skeletal pathology.

Radionuclide Studies

Radionuclide myocardial perfusion studies at rest but more typically at stress with thallium 201, technetium 99m sestamibi, or tetrofosmin are frequently used in identifying perfusion abnormalities as an indicator of ischemic chest pain, especially when a cardiac etiology is suspected. A normal stress perfusion scan may be used to exclude the diagnosis of CAD in patients in whom myocardial infarction by enzymes has been ruled out.

PET is an alternative method for evaluating myocardial perfusion deficits, using N13 ammonia or rubidium 82 agents. However, PET is not indicated in low probability patients.

V/Q lung scintigraphy can be used in patients with clinically suspected PE, but this study has been largely replaced by MDCT.

Cardiac Catheterization

Cardiac catheterization with coronary digital subtraction angiography remains the gold standard in demonstrating CAD and can permit immediate therapeutic intervention. However, there is rarely an indication to use it in low-probability patients, because the high negative predictive value of coronary CTA enables it to be used alone to exclude CAD.

Barium Swallow or Endoscopy

Esophageal disorders can be the cause of chest pain. A water-soluble or barium contrast upper GI swallowing study or endoscopy may be helpful in establishing esophageal spasm or reflux as an etiology of the chest pain.

Abdominal Ultrasonography

Abdominal ultrasound may be indicated to document cholecystitis as a cause for the chest pain. Ultrasound is also helpful in evaluating pancreatitis, other solid-organ pathology at and/or intra-abdominal abscesses and fluid collections and less frequently GI pathology.

Summary

• This document applies to patients at low risk for CAD who present with undifferentiated chest pain and without signs of ischemia in which a chest radiograph is almost universally obtained.
• Cardiac CT, as well as rest and stress single photon emission tomography myocardial perfusion imaging (SPECT MPI), owing to its high negative predictive value, is increasingly used in the evaluation of coronary disease in this population and may be incorporated into the workup algorithm of those with low-probability chest pain.
• Chest CT and transthoracic echocardiography play an important role in evaluating noncoronary or consequences of coronary causes of chest pain.
• A number of diagnostic tests, among them ultrasound of the abdomen, MRA of the aorta with or without contrast, x-ray rib views, x-ray barium swallow, and upper GI series may also be appropriate to use in evaluating noncardiac causes of chest pain.
• Typically, more invasive imaging tests such as transesophageal echocardiography or coronary angiography as well as advanced specific cardiac MRI examinations are rarely indicated in diagnosing low risk nonspecific chest pain.

Anticipated Exceptions

Nephrogenic systemic fibrosis (NSF) is a disorder with a scleroderma-like presentation and a spectrum of manifestations that can range from limited clinical sequelae to fatality. It appears to be related to both underlying severe renal dysfunction and the administration of gadolinium-based contrast agents. It has occurred primarily in patients on dialysis, rarely in patients with very limited glomerular filtration rate (GFR) (i.e., <30 mL/min/1.73 m²), and almost never in other patients. There is growing literature regarding NSF. Although some controversy and lack of clarity remain, there is a consensus that it is advisable to avoid all gadolinium-based contrast agents in dialysis-dependent patients unless the possible benefits clearly outweigh the risk, and to limit the type and amount in patients with estimated GFR rates <30 mL/min/1.73 m². For more information, please see the American College of Radiology (ACR) Manual on Contrast Media (see the "Availability of Companion Documents" field).

Abbreviations

• CTA, computed tomography angiography
• GI, gastrointestinal
• MRA, magnetic resonance angiography
• MRI, magnetic resonance imaging
• SPECT MPI, single photon emission tomography myocardial perfusion imaging
• Tc, technetium
• US, ultrasound
• V/Q, ventilation/perfusion

Relative Radiation Level Designations

Relative Radiation Level*	Adult Effective Dose Estimate Range	Pediatric Effective Dose Estimate Range
O	0 mSv	0 mSv
	<0.1 mSv	<0.03 mSv
	0.1-1 mSv	0.03-0.3 mSv
	1-10 mSv	0.3-3 mSv
	10-30 mSv	3-10 mSv
	30-100 mSv	10-30 mSv
*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as NS (not specified).

Algorithms were not developed from criteria guidelines.

The recommendations are based on analysis of the current literature and expert panel consensus.

Selection of appropriate radiologic imaging procedures for evaluation of patients with acute nonspecific chest pain with low probability of coronary artery disease (CAD)

Gadolinium-based Contrast Agents

Nephrogenic systemic fibrosis (NSF) is a disorder with a scleroderma-like presentation and a spectrum of manifestations that can range from limited clinical sequelae to fatality. It appears to be related to both underlying severe renal dysfunction and the administration of gadolinium-based contrast agents. It has occurred primarily in patients on dialysis, rarely in patients with very limited glomerular filtration rate (GFR) (i.e., <30 mL/min/1.73 m²), and almost never in other patients. Although some controversy and lack of clarity remain, there is a consensus that it is advisable to avoid all gadolinium-based contrast agents in dialysis-dependent patients unless the possible benefits clearly outweigh the risk, and to limit the type and amount in patients with estimated GFR rates <30 mL/min/1.73 m². For more information, please see the American College of Radiology (ACR) Manual on Contrast Media (see the "Availability of Companion Documents" field).

Relative Radiation Level (RRL)

Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at inherently higher risk from exposure, both because of organ sensitivity and longer life expectancy (relevant to the long latency that appears to accompany radiation exposure). For these reasons, the RRL dose estimate ranges for pediatric examinations are lower as compared to those specified for adults. Additional information regarding radiation dose assessment for imaging examinations can be found in the ACR Appropriateness Criteria® Radiation Dose Assessment Introduction document (see the "Availability of Companion Documents" field).

An American College of Radiology (ACR) Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists, and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient's clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those exams generally used for evaluation of the patient's condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the U.S. Food and Drug Administration (FDA) have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

The American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panel on Cardiac Imaging

Panel Members: Udo Hoffman, MD; Vikram Venkatesh, MD; Richard D. White, MD; Pamela K. Woodard, MD; J. Jeffrey Carr, MD, MSCE; Sharmila Dorbala, MD; James P. Earls, MD; Jill E. Jacobs, MD; Leena Mammen, MD; Edward T. Martin, III, MD; Thomas Ryan, MD; Charles S. White, MD

Not stated

This is the current release of the guideline.

This guideline updates a previous version: Stanford W, Yucel EK, Khan A, Atalay MK, Haramati LB, Ho VB, Mammen L, Rozenshtein A, Rybicki FJ, Schoepf UJ, Stein B, Woodard PK, Jaff M, Expert Panel on Cardiac Imaging. ACR Appropriateness Criteria® acute chest pain--low probability of coronary artery disease. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 4 p.

Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.

Print copies: Available from the American College of Radiology, 1891 Preston White Drive, Reston, VA 20191. Telephone: (703) 648-8900.

The following are available:

• ACR Appropriateness Criteria®. Overview. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.
• ACR Appropriateness Criteria®. Literature search process. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Evidence table development. Reston (VA): American College of Radiology; 4 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Radiation dose assessment introduction. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria® Manual on contrast media. Reston (VA): American College of Radiology; 90 p. Electronic copies: Available in PDF from the ACR Web site.

None available

This summary was completed by ECRI on February 20, 2001. The information was verified by the guideline developer on March 14, 2001. This summary was updated by ECRI on July 31, 2002. The updated information was verified by the guideline developer on October 1, 2002. This summary was updated by ECRI on March 17, 2006. This summary was updated by ECRI Institute on July 12, 2007 following the U.S. Food and Drug Administration (FDA) advisory on Troponin-1 Immunoassay. This NGC summary was completed by ECRI Institute on September 9, 2009. This summary was updated by ECRI Institute on January 13, 2011 following the U.S. Food and Drug Administration (FDA) advisory on gadolinium-based contrast agents. This NGC summary was completed by ECRI Institute on February 7, 2012.

Instructions for downloading, use, and reproduction of the American College of Radiology (ACR) Appropriateness Criteria® may be found on the ACR Web site .