Patient Population Under Consideration
This recommendation applies to adult men and women without symptoms of
heart disease or a diagnosis of cardiovascular disease (CVD). In this
recommendation, CHD refers to coronary artery disease and ischemic heart
disease.
Assessment of Risk
Accurate identification of persons at high risk for CHD events,
particularly nonfatal MI and CHD death, provides the opportunity to
intensify risk factor management to reduce the likelihood of one of
these events. In addition, identifying people at low risk may allow for a
reduction in interventions with a low benefit-to-risk ratio in this
risk stratum. Several factors are associated with higher risk for CHD
events, including older age, male sex, high blood pressure, smoking,
abnormal lipid levels, diabetes, obesity, and sedentary lifestyle.
Risk factors can be combined in many ways to allow classification of a
person's risk for a CHD event as low, intermediate, or high. Several
calculators and models are available to quantify a person's 10-year risk
for CHD events. The Framingham Adult Treatment Panel III calculator (http://hp2010.nhlbihin.net/atpiii/calculator.aspThis link goes offsite. Click to read the external link disclaimer)
performs well for the U.S. population. Persons with a 10-year risk
greater than 20% are generally considered high-risk, those with a
10-year risk less than 10% are considered low-risk, and those in the 10%
to 20% range are considered intermediate-risk.
Screening Tests
Many resting and exercise ECG abnormalities have been associated with
an increased risk for CHD events, such as MI and CHD death. Although
exercise ECG is considered more sensitive for detecting coronary artery
stenosis, the magnitude of increased risk for CHD events, as well as the
sensitivity of ECG abnormalities for predicting future events, is
similar for resting and exercise ECG1, 2.
Performing baseline ECG so that results may be compared with future ECG
findings is considered screening by the USPSTF and is not recommended
for asymptomatic adults at low risk for CHD; evidence is insufficient
about its usefulness in adults at increased risk.
For asymptomatic adults at low risk for CHD events, a resting or
exercise ECG is unlikely to provide additional information about CHD
risk beyond that obtained with conventional CHD risk factors (that is,
Framingham risk factors) and result in changes in risk stratification
that would prompt interventions and ultimately reduce CHD-related
events. False-positive results may cause harms in low-risk asymptomatic
adults; for more information about harms, go to the Suggestions for Practice Regarding the I Statement and the Discussion sections.
Treatment
Regardless of ECG findings, asymptomatic adults at increased risk for
CHD are usually managed with a combination of diet and exercise
modifications, lipid-lowering medications, aspirin, hypertension
management, and tobacco cessation. The net benefit of the use of aspirin
and the intensity of lipid-lowering therapy depends on a person's
baseline risk for CHD.
Useful Resources
The USPSTF has made recommendations on the use of aspirin to prevent
CVD, screening for lipid disorders, the use of additional risk factors
to determine intermediate CHD risk, and screening for hypertension.
These recommendations and their supporting evidence are available on the
USPSTF Web site at www.uspreventiveservicestaskforce.org.
Suggestions for Practice Regarding the I Statement
In deciding whether to screen with resting or exercise ECG in
asymptomatic adults who are at intermediate or high risk for CHD events,
clinicians should consider the following.
Potential preventable burden. Although
evidence is insufficient to determine whether screening adults at
increased risk is beneficial, those who are at intermediate risk for CHD
events have the greatest potential for net benefit from ECG screening.
Reclassification into a higher risk category might lead to more
intensive medical management that could lower the risk for CHD events,
but it might also result in harms, including such adverse medication
effects as gastrointestinal bleeding and hepatic injury. The
risk–benefit tradeoff would be most favorable if persons could be
accurately reclassified from intermediate to high risk. Regardless of
ECG findings, persons who are already at high risk should receive
intensive risk factor modification and those who are already classified
as low risk are unlikely to benefit.
For persons 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.
Although some exercise programs initially screen asymptomatic
participants with exercise ECG, evidence is insufficient to determine
the balance of benefits and harms of this practice.
Potential harms. In all
risk groups, an ECG abnormality (as a result of a true- or
false-positive result) can lead to invasive confirmatory testing and
treatments that have the potential for serious harm, including
unnecessary radiation exposure and the associated risk for cancer.
Studies report that up to 3% of asymptomatic patients with an abnormal
exercise ECG result receive angiography and up to 0.5% undergo
revascularization, even though revascularization has not been shown to
reduce CHD events in asymptomatic persons. Angiography and
revascularization are associated with risks, including bleeding,
contrast-induced nephropathy, and allergic reactions to the contrast
agent.
Current practice. Screening
with resting or exercise ECG in low-risk patients is not recommended by
any organization. However, evidence on current clinical use of
screening for CHD with resting or exercise ECG in asymptomatic patients
is sparse. Anecdotal evidence suggests that it is performed with some
frequency.
Costs. Although the cost of
resting ECG may be low, the downstream costs of resulting diagnostic
testing and treatments can be substantial.