Highlights of the 2010 ACCF/AHA Guidelines for the Assessment of Cardiovascular Risk in Asymptomatic Adults

Editor’s Note: Nanette K. Wenger, MD, sat on the writing committee that assembled the most recent version of the American College of Cardiology Foundation/American Heart Association Guidelines for the Assessment of Cardiovascular Risk in Asymptomatic Adults. She has summarized the key points of the guidelines for Cardiology Today readers in the following commentary.

The long asymptomatic latent period of coronary heart disease offers an opportunity for early preventive interventions. Relevant is the high prevalence of atherosclerotic risk factors in the US population and the information that half of all CV sudden deaths are not preceded by cardiac symptoms or diagnoses.

Nanette K. Wenger

The recently released ACCF/AHA Guideline for the Assessment of Cardiovascular Risk in Asymptomatic Adults was designed to aid the clinician in making informed decisions about appropriate lifestyle and pharmacologic interventions to reduce CV risk in such patients. A validated methodology to evaluate the prognostic value of risk factors and risk markers was used to guide risk testing, such that the intensity of the intervention reflected the severity of the risk. This approach has the potential to lower the high burden of coronary death in asymptomatic adults.

Key considerations

To be recommended, a risk factor or risk marker must have independent statistical association with risk beyond the traditional readily available inexpensive risk markers, have incremental predictive value, and the ability to reclassify risk compared with traditional risk factors alone. Added considerations include its efficacy in assignment of short-term and long-term risk status, its accuracy and reproducibility, and the requirement for serial testing, which may be indicated to accurately assess risk for some tests.

Variables explored were the cost of the test or procedure (both financial and related to the risks of a test); the effect on the performance of added testing (both noninvasive and invasive) with consideration of post-test referral bias; the effect on initiation of lifestyle and pharmacologic interventions; the financial and emotional effects on the individual undergoing testing; and the effect on short-term and long-term outcomes. [A figure containing classification of recommendations and levels of evidence is available here.]

Limited data, unmet needs and implications

Data are limited regarding the role of novel biomarkers and imaging studies in the risk assessment of asymptomatic adults in selected populations of asymptomatic adults. These include women, older adults, racial and ethnic minorities, diabetes, chronic kidney disease, and issues of geographic, environmental and neighborhood risk.

Among tests of value, unmet needs include ascertainment of whether the test/procedure is useful to motivate patients to adhere to recommended interventions; is useful to guide therapy; is useful as a repeat measure to monitor effects of therapy; or is of value in improving health outcomes.

Asymptomatic adults are broadly characterized into low-, intermediate- or high-risk subsets, with the intensity and type of treatments based on assessments of risk.

The initial step is the ascertainment of a global risk score and family history of atherosclerotic CVD. These recommendations are Class I and are simple and inexpensive.

If an asymptomatic adult is low risk, no further testing is necessary. If a patient is high risk (CHD or CHD risk equivalents), intensive preventive interventions are warranted and there is no incremental benefit of added testing. If an asymptomatic adult is intermediate risk, additional testing can further define risk status. Recommendations are classified thusly: Benefit exceeds cost and risk (IIa); less robust evidence for benefit but shown to be helpful in selected patients (IIb); and not recommended for use due to no or limited evidence of benefit, potentially causing harm (III).

Recommended approaches

Global risk scores such as the Framingham risk score should be obtained for risk assessment in all asymptomatic adults without a clinical history of CHD (I B). These scores combine multiple traditional risk factor measurements into a single quantitative estimate of risk. A family history of atherothrombotic CVD should be obtained in all asymptomatic adults (I B), but genotype testing is not recommended (III B). The measurement of lipid parameters, including lipoproteins, apolipoproteins, and particle size and density, beyond a standard fasting lipid profile, is not recommended (III C).

Circulating blood markers and associated conditions

The measurement of natriuretic peptides is not recommended (III B). Measuring CRP can be useful in the selection of patients for statin therapy in men aged at least 50 years or women aged at least 60 years with LDL levels less than 130 mg/dL; not on lipid-lowering, hormone replacement or immunosuppressant therapy; without clinical CHD, diabetes, chronic kidney disease, severe inflammatory conditions or contraindications to statins (IIa B). CRP measurement may be reasonable in asymptomatic intermediate-risk men aged 50 years or younger or women aged 60 years or younger (IIb B), but it is not recommended for CV risk assessment in asymptomatic high-risk adults (III B) or in low-risk men aged 50 years or younger or women aged 60 years or younger (III B).

Measurement of HbA1c may be reasonable in asymptomatic adults without a diagnosis of diabetes (IIb B). Urinalysis to detect microalbuminuria is reasonable in asymptomatic adults with hypertension or diabetes (IIa B) or may be reasonable in asymptomatic adults at intermediate risk without hypertension or diabetes (IIb B). The measurement of lipoprotein-associated phospholipase A2 (Lp-PLA2) may be reasonable for intermediate-risk asymptomatic adults (IIb B).

Testing recommendations

According to the guidelines, the following recommendations should be considered based upon the patient profile:

• Resting Electrocardiogram (ECG) — A resting ECG is reasonable in asymptomatic adults with hypertension or diabetes (IIa C) and may be considered in asymptomatic adults without hypertension or diabetes (IIb C).
• Transthoracic Echocardiogram — Echocardiography to detect left ventricular hypertrophy may be considered in asymptomatic adults with hypertension (IIb B), but it is not recommended in asymptomatic adults without hypertension (III C).
• Measurement of Carotid Intima-media Thickness (IMT) — Measurement of carotid artery IMT is reasonable in asymptomatic adults at intermediate risk, using published recommendations on required equipment, technical approach, and operator experience and training (IIa B).
• Brachial/Peripheral Flow-Mediated Dilation — Peripheral arterial flow-mediated dilation studies are not recommended (III B).
• Measures of Arterial Stiffness — Measures of arterial stiffness are not recommended outside of research settings (III C).
• Measurement of Ankle-Brachial Index — Measurement of ankle-brachial index is reasonable in asymptomatic adults at intermediate risk (IIa B).
• Exercise Electrocardiography (ECG) — An exercise ECG may be considered in intermediate-risk asymptomatic adults (including sedentary adults considering starting a vigorous exercise program), particularly when attention is paid to non-ECG markers such as exercise capacity (IIb B).
• Stress Echocardiography — Stress echocardiography is not indicated in low- or intermediate-risk asymptomatic adults (III C). Exercise or pharmacological stress echocardiography is primarily used in advanced cardiac evaluation of symptoms suspected of representing CHD and/or estimation of prognosis in patients with known CAD or assessment of patients with valvular heart disease.
• Myocardial Perfusion Imaging (MPI) — Stress MPI may be considered for advanced CV risk assessment in asymptomatic adults with diabetes or with a strong family history of CHD or when previous risk assessment testing suggests high risk of CHD, such as a coronary artery calcium (CAC) score of 400 or more (IIb C). Stress MPI is not indicated in low- or intermediate-risk asymptomatic adults (III C). Exercise or pharmacologic stress MPI is primarily used in advanced cardiac evaluation of symptoms suspected of representing CHD and/or estimation of prognosis in patients with known CAD.
• Calcium Scoring Methods — Measurement of CAC is reasonable in asymptomatic adults at intermediate risk (10%-20% 10-year risk) (IIa B). Measurement of CAC may be reasonable for adults at low to intermediate risk (6%-10% 10-year risk). Adults at low risk (<6% 10-year risk) should not undergo CAC measurement (III B).
• Coronary Computed Tomography Angiography — Coronary CTA is not recommended (III C).
• Magnetic Reasonance Imaging of Plaque — MRI for detection of vascular plaque is not recommended (III C).
• Risk Assessent for Patients with Diabetes — In asymptomatic adults with diabetes aged at least 40 years, measurement of CAC is reasonable (IIa B). Measurement of HbA1c may be considered in asymptomatic adults with diabetes (IIb B). Stress MPI may be considered for advanced CV risk assessment in asymptomatic adults with diabetes or when previous risk assessment testing suggests high risk of CHD, such as a CAC score of 400 or more (IIb C).
• Considerations for Women — Because of frequent reporting of underutilization of diagnostic and preventive services among female patients, it is recommended that a global risk score be obtained in all symptomatic women (I B) and a family history of CVD (I B).

Noncardiac tests and cardiac or vascular tests that are not recommended for risk assessment in asymptomatic adults are summarized in Table 1 and Table 2 (above).

Nanette K. Wenger, MD, is a professor of medicine at Emory University in Atlanta and a member of the Cardiology Today Editorial Board.

For more information:

• Greenland P. J Am Coll Cardiol. 2010;56:2182-2199.