This is the current release of the guideline.

This release updates a previously published guideline: U.S. Preventive Services Task Force. Chapter 1. Screening for asymptomatic coronary artery disease. In: Guide to clinical preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins; 1996. p 3-14.

• Coronary heart disease (CHD)
• Coronary artery disease (CAD)

Prevention
Screening

Cardiology
Family Practice
Internal Medicine
Preventive Medicine

Advanced Practice Nurses
Allied Health Personnel
Nurses
Physician Assistants
Physicians

• To summarize the current U.S. Preventive Services Task Force (USPSTF) recommendations on screening for coronary heart disease and the supporting evidence
• To update the 1996 recommendations contained in the Guide to Clinical Preventive Services, Second Edition

Asymptomatic adults seen in primary care settings

Screening for coronary artery disease using medical history, physical examination and cardiac screening tests, including resting electrocardiogram, exercise treadmill testing or electron beam computerized tomography

• Key Question No. 1: Does testing for asymptomatic coronary artery disease (CAD) with electrocardiography (ECG), exercise electrocardiography treadmill testing (ETT), or electron beam computerized tomography (EBCT) lead to improvement in coronary heart disease (CHD) health outcomes?
• Key Question No. 2: Does testing for asymptomatic CAD with ECG, ETT, or EBCT lead to increased use of CHD risk-reducing treatments?
• Key Question No. 3: Do any of the screening tests for asymptomatic CAD (ECG, ETT, or EBCT) provide additional prognostic information over and above that from the traditional risk factors?

Hand-searches of Published Literature (Primary Sources)
Hand-searches of Published Literature (Secondary Sources)
Searches of Electronic Databases

Note from the National Guideline Clearinghouse (NGC): A systematic evidence review was prepared by RTI International-University of North Carolina Evidence-based Practice Center (EPC) for the Agency for Healthcare Research and Quality (AHRQ) for use by the U.S. Preventive Services Task Force (USPSTF) (see the "Companion Documents" field).

Screening for Asymptomatic Coronary Artery Disease

Search Strategy

To identify the relevant literature, a MEDLINE search was conducted for years 1966 through June 2002. The following MeSH headings and keywords were used: (coronary disease and asymptomatic) or (myocardial Infarction and silent) and (electrocardiography or exercise test or tomography, x-ray computed or echocardiography) and (diagnosis or prognosis), limited to English language and human subjects. In addition to these general searches, MEDLINE was searched for articles on several specific electrocardiographic findings, including left ventricular hypertrophy, ventricular arrhythmias, and ST segment changes or T wave inversions. Hand searches of the bibliographies of key articles were also performed, and other recent systematic reviews were used, when available, to supplement the literature searches.

Inclusion Criteria

Two reviewers examined the abstracts of the articles identified in the initial MEDLINE search and resolved disagreements about inclusion by consensus. Two reviewers examined the full text of the remaining articles to determine final eligibility. To be eligible, studies had to be performed in patients with no previous history of cardiovascular disease and to report the independent effect of the test on the incidence of CHD events, the proportion of patients receiving CHD risk-reducing treatments, or the risk of future CHD events. When reporting the prognostic benefit of electrocardiography (ECG), exercise electrocardiography treadmill testing (ETT) and electron beam computerized tomography (EBCT), studies have used different means of characterizing results. Many studies have reported the outcomes in terms of independent relative risk associated with a positive (versus a negative) screening test. Others have used diagnostic test terminology, such as sensitivity and specificity or positive predictive value. In such cases, the terms are used to indicate test accuracy over the entire follow-up period, rather than at one point in time (e.g. sensitivity is the proportion of all patients who go on to have a CHD event that had positive screening tests at baseline; positive predictive value is the proportion of all patients screening positive that go on to have a CHD event).

Exercise Tolerance Testing to Screen for Coronary Heart Disease

Search Strategy

To identify the relevant literature, a MEDLINE search was conducted for years 1966 through February 2003. The following exploded MeSH headings were used: coronary heart disease, exercise test, mass screening, and the keywords "asymptomatic" and "screening," limited to English language and human subjects. To supplement the literature searches, hand searches were performed of the bibliographies of key articles. Other recent systematic reviews were also used, when available. References provided by expert reviewers that had not been identified by other mechanisms, were included, as well.

Inclusion Criteria

Two reviewers examined the abstracts of the articles identified in the initial MEDLINE search and selected a subset for full text review. The same reviewers examined the full text of the selected articles to determine final eligibility. One reviewer extracted information from eligible articles into evidence tables; a second reviewer checked the tables. They resolved disagreements by consensus.

To be eligible, studies for inclusion had to be performed in participants with no previous history of cardiovascular disease or to provide subset analysis for this group. Included studies concerning the detection of severe coronary artery obstruction reported the total number of persons screened, to obtain the sample of persons with an abnormal exercise tolerance testing and the proportion that were found to have CHD on angiography. The yield of exercise tolerance testing screening was determined by dividing the number of participants found to have abnormal angiography by the total number screened.

For the prognostic benefit of exercise tolerance testing, included studies reported the independent value of the test for predicting the incidence of CHD events. Studies that did not use statistical methodology to control for the effect of other risk factors (e.g., age, systolic blood pressure) on the estimate of the prognostic strength of a positive exercise tolerance testing were not included. Excluded studies are recorded in a separate table. Studies used different means of characterizing the prognostic benefit of screening exercise tolerance testing. Many studies reported outcomes in terms of independent relative risk associated with a positive (versus a negative) screening test. Others used diagnostic test terminology, such as sensitivity and specificity or positive predictive value. In such cases, the terms are used to indicate test accuracy over the entire follow-up period rather than at 1 point in time. For example, sensitivity is defined as: of all patients who go on to have a CHD event, the proportion who had tested positive on exercise tolerance testing; positive predictive value is defined as: of all patients who had a positive screening test, the proportion that went on to have a CHD event.

Screening for Asymptomatic Coronary Artery Disease

No studies were retrieved that examined the effect of screening asymptomatic patients with electrocardiography (ECG), exercise electrocardiography treadmill testing (ETT), or electron beam computerized tomography (EBCT) on coronary heart disease (CHD) outcomes.

Two fair quality studies examined the effect of a positive EBCT on self-reported adoption of risk-reducing behaviors and found mixed results.

Exercise Tolerance Testing to Screen for Coronary Heart Disease

A total of 713 articles were identified for review from the literature search. After reviewing the abstracts, 55 articles were retained that examined the diagnostic or prognostic significance of screening exercise tolerance testing. After full article review, 31 articles were kept, representing 29 studies that met the inclusion criterion. Another 11 articles were included through a review of reference lists and input of expert reviewers.

Three good quality studies were identified that estimated the cost effectiveness of exercise tolerance testing for the identification of asymptomatic severe prevalent CHD.

Weighting According to a Rating Scheme (Scheme Given)

The U.S. Preventive Services Task Force grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor):

Good

Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.

Fair

Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.

Poor

Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.

Review of Published Meta-Analyses
Systematic Review with Evidence Tables

Note from the National Guideline Clearinghouse (NGC): A systematic evidence review was prepared by RTI International-University of North Carolina Evidence-based Practice Center (EPC) for the Agency for Healthcare Research and Quality (AHRQ) for use by the U.S. Preventive Services Task Force (USPSTF) (see the "Companion Documents" field).

Screening for Asymptomatic Coronary Artery Disease

Quality of the included articles was rated according to criteria developed by the U.S. Preventive Services Task Force (USPSTF) Methods Work Group. The final set of eligible articles was used to create evidence tables and a draft report.

Exercise Tolerance Testing to Screen for Coronary Heart Disease

EPC staff rated the quality of the included articles according to criteria developed by the USPSTF Methods Work Group. Two tables were constructed containing only studies judged "good". Another table considered several factors which affect quality, chiefly the percentage of patients with a positive exercise tolerance testing who underwent catheterization and how completely the study assessed outcomes. The final set of eligible articles were used to create evidence tables and produce the larger evidence report, which also included evaluation of rest electrocardiography and electron beam computed tomography scan for coronary calcium.

To assess whether there was a relationship between sensitivity of exercise tolerance testing for future coronary heart disease and the length of follow-up time, the correlation between reported sensitivity and mean follow up time, using STATA 7.0 statistical software, was examined.

Balance Sheets
Expert Consensus

When the overall quality of the evidence is judged to be good or fair, the U.S. Preventive Services Task Force (USPSTF) proceeds to consider the magnitude of net benefit to be expected from implementation of the preventive service. Determining net benefit requires assessing both the magnitude of benefits and the magnitude of harms and weighing the two.

The USPSTF classifies benefits, harms, and net benefits on a 4-point scale: "substantial," "moderate," "small," and "zero/negative."

"Outcomes tables" (similar to 'balance sheets') are the USPSTF's standard resource for estimating the magnitude of benefit. These tables, prepared by the topic teams for use at USPSTF meetings, compare the condition specific outcomes expected for a hypothetical primary care population with and without use of the preventive service. These comparisons may be extended to consider only people of specified age or risk groups or other aspects of implementation. Thus, outcomes tables allow the USPSTF to examine directly how the preventive services affects benefits for various groups.

When evidence on harms is available, the topic teams assess its quality in a manner like that for benefits and include adverse events in the outcomes tables. When few harms data are available, the USPSTF does not assume that harms are small or nonexistent. It recognizes a responsibility to consider which harms are likely and judge their potential frequency and the severity that might ensue from implementing the service. It uses whatever evidence exists to construct a general confidence interval on the 4-point scale (e.g., substantial, moderate, small, and zero/negative).

Value judgments are involved in using the information in an outcomes table to rate either benefits or harms on the USPSTF’s 4-point scale. Value judgments are also needed to weigh benefits against harms to arrive a rating of net benefit.

In making its determinations of net benefit, the USPSTF strives to consider what it believes are the general values of most people. It does this with greater confidence for certain outcomes (e.g., death) about which there is little disagreement about undesirability, but it recognizes that the degree of risk people are willing to accept to avert other outcomes (e.g., cataracts) can vary considerably. When the USPSTF perceives that preferences among individuals vary greatly, and that these variations are sufficient to make trade-off of benefits and harms a 'close-call', then it will often assign a C recommendation (see the "Recommendation Rating Scheme" field). This recommendation indicates the decision is likely to be sensitive to individual patient preferences.

The USPSTF uses its assessment of the evidence and magnitude of net benefit to make recommendations. The general principles the USPSTF follows in making recommendations are outlined in Table 5 of the companion document cited below. The USPSTF liaisons on the topic team compose the first drafts of the recommendations and rationale statements, which the full panel then reviews and edits. Recommendations are based on formal voting procedures that include explicit rules for determining the views of the majority.

From: Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow, CD, Teutsch SM, Atkins D. Current methods of the U.S. Preventive Services Task Force: a review of the process. Methods Work Group, Third U.S. Preventive Services Task Force. Am J Prev Med 2001 Apr;20(3S):21-35.

The USPSTF grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms):

A

The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms.

B

The USPSTF recommends that clinicians provide [this service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health outcomes and concludes that benefits outweigh harms.

C

The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes that the balance of benefits and harms is too close to justify a general recommendation.

D

The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh benefits.

I

The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that the [service] is effective is lacking, of poor quality, or conflicting and the balance of benefits and harms cannot be determined.

Three studies have attempted to estimate the cost-effectiveness of screening to identify prevalent coronary artery obstruction. In 1989, a decision analysis model was used to estimate the clinical effectiveness and cost-effectiveness of exercise testing in asymptomatic adults. The model was structured so that the benefit of screening was achieved through detection of patients with severe disease who would benefit from revascularization. Only direct costs were considered. Levels were based on reimbursement rates at the time of the study (late 1980’s): exercise test ($165), angiography ($3595), and coronary artery bypass surgery ($31,178). No discounting rate was given. It was found that screening 60 year-old men had a cost per life-year saved of $24,600; for women, the cost was $47,606. For persons 40 years of age, the cost-effectiveness ratios were much higher: $80,349 per life year saved for men and $216,496 per life year saved for women.

The presence or absence of CHD risk factors affected the cost-effectiveness ratios. For 60-year-old men with no risk factors, the cost per life year saved was $44,332; for men with one or more CHD risk factors, it was $20,504. The authors concluded that routine screening was not warranted in general but that it may be beneficial for persons at increased risk for CHD (e.g., older men with 1 or more risk factors). An earlier cost-effectiveness analysis of screening exercise tolerance testing reached similar findings.

A group of researchers conducted a cost analysis of data from their study of the clinical yield of screening exercise tolerance testing to detect unsuspected severe coronary artery obstruction. They sampled more than 4,000 persons referred to the Cleveland Clinic for screening exercise tolerance testing. Cost data came from 1994 Medicare reimbursement rates: $110 for exercise testing, $1780 for angiography, and 27,270 for coronary artery bypass surgery. Screening identified 19 cases of patients with severe coronary artery obstruction (0.44% of the cohort), of these, 14 had subsequent bypass surgery. The authors estimated a cost of $39,623 to identify 1 case of severe CAD by screening exercise tolerance testing. The estimated cost per year of life saved was $55,274.

Based on these studies, it appears that screening with exercise treadmill testing and performing bypass surgery on those with severe obstructions is relatively cost-effective compared with other, better accepted types of preventive care, such as mammography in women ages 50-69.

From: Pignone M, Fowler-Brown A, Pletcher M, Tice JA. Screening for Asymptomatic Coronary Artery Disease. Rockville (MD); Agency for Healthcare Research and Quality; 2004 Feb. (Systematic Evidence Review No. 22).

Comparison with Guidelines from Other Groups
External Peer Review
Internal Peer Review

Peer Review: Before the U.S. Preventive Services Task Force (USPSTF) makes its final determination about recommendations on a given preventive service, the Evidence-based Practice Center and the Agency for Healthcare Research and Quality send a draft systematic evidence review to 4 to 6 external experts and to federal agencies and professional and disease-based health organizations with interests in the topic. They ask the experts to examine the review critically for accuracy and completeness, and to respond to a series of specific questions about the document. After assembling these external review comments and documenting the proposed response to key comments, the topic team presents this information to the Task Force in memo form. In this way, the Task Force can consider these external comments and a final version of the systematic review before it votes on its recommendations about the service. Draft recommendations are then circulated for comment from reviewers representing professional societies, voluntary organizations and Federal agencies. These comments are discussed before the whole U.S. Preventive Services Task Force final recommendations are made.

Recommendation of Others: Recommendations for screening for coronary heart disease (CHD) from the following groups were discussed: American Heart Association/American College of Cardiology (AHA/ACC), and American Academy of Family Physicians.

None provided

The type of evidence supporting the recommendations is identified in the "Major Recommendations" field.

Screening with electrocardiogram (ECG), exercise treadmill testing (ETT), and electron beam computed tomography (EBCT) could potentially reduce coronary heart disease (CHD) events in 2 ways: either by detecting people at high risk for CHD events who could benefit from more aggressive risk factor modification, or by detecting people with existing severe coronary artery stenosis (CAS) whose life can could be prolonged by coronary artery bypass graft surgery (CABG). However, the evidence is inadequate to determine the extent to which people detected through screening in either situation would benefit from either type of intervention.

Subgroups Most Likely to Benefit

• Screening may potentially be of greatest benefit to those presumed to be at intermediate risk for CHD who could be reclassified as being at high risk (and thus treated more aggressively) after additional testing.
• For people in certain occupations, such as pilots and heavy equipment operators (for whom sudden incapacitation or sudden death may endanger the safety of others), considerations other than the health benefit to the individual patient may influence the decision to screen for CHD.

Potential harms of screening asymptomatic patients for coronary heart disease (CHD) include unnecessary invasive testing (e.g., coronary angiography) and ‘labeling’ of those who have had false-positive test results. In low-risk asymptomatic populations, most positive electrocardiogram (ECG) test results occur in those who will not have a CHD event in the next 5 to 10 years. One study reported that 71% of those without symptoms who had an abnormal exercise treadmill test (ETT) had no angiographically demonstrable coronary artery stenosis (CAS). While the yield of screening is low in those at low risk for CHD, the potential for harm from false-positive tests is high. The U.S. Preventive Services Task Force (USPSTF) judged that the benefits of screening people at low risk for CHD would not outweigh the potential harms.

The U.S. Preventive Services Task Force recommendations are independent of the U.S. government. They do not represent the views of the Agency for Healthcare Research and Quality (AHRQ), the U.S. Department of Health and Human Services, or the U.S. Public Health Service.

Staying Healthy

Effectiveness

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

1996 (revised 2004 Feb 17)

United States Preventive Services Task Force - Independent Expert Panel

The U.S. Preventive Services Task Force (USPSTF) is a Federally-appointed panel of independent experts. Conclusions of the U.S. Preventive Services Task Force do not necessarily reflect policy of the U.S. Department of Health and Human Services (DHHS) or its agencies.

United States Government

U.S. Preventive Services Task Force (USPSTF)

The U.S. Preventive Services Task Force has an explicit policy concerning conflict of interest. All members and evidence-based practice center (EPC) staff disclose at each meeting if they have an important financial conflict for each topic being discussed. Task Force members and EPC staff with conflicts can participate in discussions about evidence, but members abstain from voting on recommendations about the topic in question.

From: Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow, CD, Teutsch SM, Atkins D. Current methods of the U.S. Preventive Services Task Force: a review of the process. Methods Work Group, Third U.S. Preventive Services Task Force. Am J Prev Med 2001 Apr;20(3S):21-35.

This is the current release of the guideline.

This release updates a previously published guideline: U.S. Preventive Services Task Force. Chapter 1. Screening for asymptomatic coronary artery disease. In: Guide to clinical preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins; 1996. p 3-14.

This summary was completed by ECRI on June 30, 1998. The information was verified by the guideline developer on December 1, 1998. This summary was updated on ECRI on February 3, 2004.