Guide to Clinical Preventive Services, 2007

Heart and Vascular Diseases

Screening for Abdominal Aortic Aneurysm

Summary of Recommendations The U.S. Preventive Services Task Force (USPSTF) recommends one-time screening for abdominal aortic aneurysm (AAA) by ultrasonography in men aged 65 to 75 who have ever smoked. Rating: B Recommendation. The USPSTF makes no recommendation for or against screening for AAA in men aged 65 to 75 who have never smoked. Rating: C Recommendation. The USPSTF recommends against routine screening for AAA in women. Rating: D Recommendation.

This USPSTF recommendation was first published in: Ann Intern Med. 2005;142:198-202. http://www.ahrq.gov/clinic/uspstf05/aaascr/aaars.htm.

Clinical Considerations

• The major risk factors for abdominal aortic aneurysm (AAA) include age (being 65 or older), male sex, and a history of ever smoking (at least 100 cigarettes in a person's lifetime). A first-degree family history of AAA requiring surgical repair also elevates a man's risk for AAA; this may also be true for women but the evidence is less certain. There is only a modest association between risk factors for atherosclerotic disease and AAA.
• Screening for AAA would most benefit those who have a reasonably high probability of having an AAA large enough, or that will become large enough, to benefit from surgery. In general, adults younger than age 65 and adults of any age who have never smoked are at low risk for AAA and are not likely to benefit from screening. Among men aged 65 to 74, an estimated 500 who have ever smoked—or 1,783 who have never smoked—would need to be screened to prevent 1 AAA-related death in the next 5 years. As always, clinicians must individualize recommendations depending on a patient's risk and likelihood of benefit. For example, some clinicians may choose to discuss screening with male nonsmokers nearing age 65 who have a strong first-degree family history of AAA that required surgery.
• The potential benefit of screening for AAA among women aged 65 to 75 is low because of the small number of AAA-related deaths in this population. The majority of deaths from AAA rupture occur in women aged 80 or older. Because there are many competing health risks at this age, any benefit of screening for AAA would be minimal. Individualization of care, however, is still required. For example, a clinician may choose to discuss screening in the unusual circumstance in which a healthy female smoker in her early 70s has a first-degree family history for AAA that required surgery.
• Operative mortality for open surgical repair of an AAA is 4 to 5 percent, and nearly one-third of patients undergoing this surgery have other important complications (e.g., cardiac and pulmonary). Additionally, men having this surgery are at increased risk for impotence.
• Endovascular repair of AAAs (EVAR) is currently being used as an alternative to open surgical repair. Although recent studies have shown a short-term mortality and morbidity benefit of EVAR compared with open surgical repair, the long-term effectiveness of EVAR to reduce AAA rupture and mortality is unknown. The long-term harms of EVAR include late conversion to open repair and aneurysmal rupture. EVAR performed with older-generation devices is reported to have an annual rate of rupture of 1 percent and conversion to open surgical repair of 2 percent. The conversion to open surgical repair is associated with a peri-operative mortality of about 24 percent. The long-term harms of newer generation EVAR devices are yet to be reported.
• For most men, 75 years may be considered an upper age limit for screening. Patients cannot benefit from screening and subsequent surgery unless they have a reasonable life expectancy. The increased presence of comorbidities for people aged 75 and older decreases the likelihood that they will benefit from screening.
• Ultrasonography has a sensitivity of 95 percent and specificity of nearly 100 percent when performed in a setting with adequate quality assurance. The absence of quality assurance is likely to lower test accuracy. Abdominal palpation has poor accuracy and is not an adequate screening test.
• One-time screening to detect an AAA using ultrasonography is sufficient. There is negligible health benefit in re-screening those who have normal aortic diameter on initial screening.
• Open surgical repair for an AAA of at least 5.5 cm leads to an estimated 43-percent reduction in AAA-specific mortality in older men who undergo screening. However, there is no current evidence that screening reduces all-cause mortality in this population.
• In men with intermediate-sized AAAs (4.0-5.4 cm), periodic surveillance offers comparable mortality benefit to routine elective surgery with the benefit of fewer operations. Although there is no evidence to support the effectiveness of any intervention in those with small AAAs (3.0-3.9 cm), there are expert opinion-based recommendations in favor of periodic repeat ultrasonography for these patients.

Return to Contents

Aspirin for the Primary Prevention of Cardiovascular Events

Summary of Recommendation The U.S. Preventive Services Task Force (USPSTF) strongly recommends that clinicians discuss aspirin chemoprevention with adults who are at increased risk for coronary heart disease (CHD). Discussions with patients should address both the potential benefits and harms of aspirin therapy. Rating: A Recommendation.

This USPSTF recommendation was first published in:  Ann Intern Med 2002;136(2):157-60. http://www.ahrq.gov/clinic/3rduspstf/aspirin/asprr.htm.

Clinical Considerations

• Decisions about aspirin therapy should take into account overall risk for coronary heart disease. Risk assessment should include asking about the presence and severity of the following risk factors: age, sex, diabetes, elevated total cholesterol levels, low levels of high-density lipoprotein (HDL) cholesterol, elevated blood pressure, family history (in younger adults), and smoking. Tools that incorporate specific information on multiple risk factors provide more accurate estimation of cardiovascular risk than categorizations based simply on counting the numbers of risk factors (www.intmed.mcw.edu/clincalc/heartrisk.html).¹⁶
• Men older than 40 years, postmenopausal women, and younger people with risk factors for CHD (e.g., hypertension, diabetes, or smoking) are at increased risk for heart disease and may wish to consider aspirin therapy. Table 2 shows how estimates of the type and magnitude of benefits and harms associated with aspirin therapy vary with an individual's underlying risk for coronary heart disease. Although balance of benefits and harms is most favorable in high-risk people (5-year risk > 3 percent), some people at lower risk may consider the potential benefits of aspirin to be sufficient to outweigh the potential harms.
• Discussions about aspirin therapy should focus on potential coronary heart disease benefits, such as prevention of myocardial infarction, and potential harms, such as gastrointestinal and intracranial bleeding. Discussions should take into account individual preferences and risk aversions concerning myocardial infarction, stroke, and gastrointestinal bleeding.
• Although the optimal timing and frequency of discussions related to aspirin therapy are unknown, reasonable options include every 5 years in middle-aged and older people or when other cardiovascular risk factors are detected.
• Most participants in the primary prevention trials of aspirin therapy have been men between 40 and 75 years of age. Current estimates of benefits and harms may not be as reliable for women and older men.
• Although older patients may derive greater benefits because they are at higher risk for CHD and stroke, their risk for bleeding may be higher.
• Uncontrolled hypertension may attenuate the benefits of aspirin in reducing CHD.
• The optimum dose of aspirin for chemoprevention is not known. Primary and secondary prevention trials have demonstrated benefits with a variety of regimens, including 75 mg per day, 100 mg per day, and 325 mg every other day. Doses of approximately 75 mg per day appear as effective as higher doses; whether doses below 75 mg per day are effective has not been established. Enteric-coated or buffered preparations do not clearly reduce adverse gastrointestinal effects of aspirin. Uncontrolled hypertension and concomitant use of other nonsteroidal anti-inflammatory agents or anticoagulants increase risk for serious bleeding.

Return to Contents

Screening for Coronary Heart Disease

Summary of Recommendations The U.S. Preventive Services Task Force (USPSTF) recommends against routine screening with resting electrocardiography (ECG), exercise treadmill test (ETT), or electron-beam computerized tomography (EBCT) scanning for coronary calcium for either the presence of severe coronary artery stenosis (CAS) or the prediction of coronary heart disease (CHD) events in adults at low risk for CHD events. Rating: D Recommendation. The USPSTF found insufficient evidence to recommend for or against routine screening with ECG, ETT, or EBCT scanning for coronary calcium for either the presence of severe CAS or the prediction of CHD events in adults at increased risk for CHD events. Rating: I Recommendation.

This USPSTF recommendation was first published in:  Ann Intern Med 2004;140:569-72. http://www.ahrq.gov/clinic/3rduspstf/chd/chdrs.htm.

Clinical Considerations

• Several factors are associated with a higher risk for CHD events (the major ones are nonfatal myocardial infarction and coronary death), including older age, male gender, high blood pressure, smoking, abnormal lipid levels, diabetes, obesity, and sedentary lifestyle. A person's risk for CHD events can be estimated based on the presence of these factors. Calculators are available to ascertain a person's risk for having a CHD event; for example, a calculator to estimate a person's risk for a CHD event in the next 10 years can be accessed at http://hin.nhlbi.nih.gov/atpiii/calculator.asp?usertype=prof. Although the exact risk factors that constitute each of these categories (low or increased risk) have not been established, younger adults (i.e., men < 50 years and women < 60 years) who have no other risk factors for CHD (< 5 percent-10 percent 10-year risk) are considered to be at low risk. Older adults, or younger adults with 1 or more risk factors (> 15 percent-20 percent 10-year risk), are considered to be at increased risk.
• Screening with ECG, ETT, and EBCT could potentially reduce 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 CAS whose life could be prolonged by coronary artery bypass grafting (CABG) surgery. 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.
• The consequences of false-positive tests may potentially outweigh the benefits of screening. False-positive tests are common among asymptomatic adults, especially women, and may lead to unnecessary diagnostic testing, over-treatment, and labeling.
• Because the sensitivity of these tests is limited, screening could also result in false-negative results. A negative test does not rule out the presence of severe CAS or a future CHD event.
• 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.
• Although some exercise programs initially screen asymptomatic participants with ETT, there is not enough evidence to determine the balance of benefits and harms of this practice.

Return to Contents

Screening for High Blood Pressure

Summary of Recommendations The U.S. Preventive Services Task Force (USPSTF) strongly recommends that clinicians screen adults aged 18 and older for high blood pressure. Rating: A Recommendation. The USPSTF concludes that the evidence is insufficient to recommend for or against routine screening for high blood pressure in children and adolescents to reduce the risk of cardiovascular disease. Rating: I Recommendation.

This USPSTF recommendation was first published by: Agency for Healthcare Research and Quality, Rockville, MD. July 2003. http://www.ahrq.gov/clinic/uspstf/uspshype.htm.

Clinical Considerations

• Office measurement of blood pressure is most commonly done with a sphygmomanometer. High blood pressure (hypertension) is usually defined in adults as a systolic blood pressure (SBP) of 140 mm Hg or higher, or a diastolic blood pressure (DBP) of 90 mm Hg or higher. Due to variability in individual blood pressure measurements (occurring as a result of instrument, observer, and patient factors), it is recommended that hypertension be diagnosed only after two or more elevated readings are obtained on at least two visits over a period of one to several weeks.
• There are some data to suggest that ambulatory blood pressure measurement (that provides a measure of the average blood pressure over 24 hours) may be a better predictor of clinical cardiovascular outcome than clinic-based approaches; however, ambulatory blood pressure measurement is subject to many of the same errors as office blood pressure measurement.
• The relationship between SBP and DBP and cardiovascular risk is continuous and graded. The actual level of blood pressure elevation should not be the sole factor in determining treatment. Clinicians should consider the patient's overall cardiovascular risk profile, including smoking, diabetes, abnormal blood lipids, age, sex, sedentary lifestyle, and obesity, in making treatment decisions.
• Hypertension in children has been defined as blood pressure above the 95th percentile for age, sex, and height. Up to 28 percent of children have secondary hypertension, i.e., high blood pressure due to causes such as coarctation of the aorta, renal parenchymal disease, renal artery stenosis, and other congenital malformations. On the basis of expert opinion, several organizations, including the American Academy of Pediatrics (AAP), American Heart Association (AHA), and American Medical Association (AMA), recommend routine screening of asymptomatic adolescents and children during preventive care visits, based on the potential for identifying treatable causes of secondary hypertension, such as coarctation of aorta. However, there are limited data on the benefits or risks of screening and treating such underlying causes of hypertension in children. The decision to screen children and adolescents for hypertension remains a matter of clinical judgment.
• Evidence is lacking to recommend an optimal interval for screening adults for high blood pressure. The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 6) recommends screening every 2 years for persons with SBP and DBP below 130 mm Hg and 85 mm Hg, respectively, and more frequent intervals for screening those with blood pressure at higher levels.
• A variety of pharmacological agents are available to treat high blood pressure. JNC 6 guidelines for treatment of high blood pressure can be accessed at www.nhlbi.nih.gov/guidelines/hypertension/jncintro.htm. The JNC 6-recommended goal of treatment is to achieve and maintain SBP below 140 mm Hg and DBP below 90 mm Hg, and lower if tolerated. Evidence indicates that reducing DBP to below 80 mm Hg appears to be beneficial for patients with hypertension and diabetes. In considering the effectiveness of treatment for hypertension, it must be noted that a given treatment's ability to lower blood pressure may not correspond directly to its ability to reduce cardiovascular events.
• Nonpharmacological therapies, such as reducing dietary sodium intake, potassium supplementation, increased physical activity, weight loss, stress management, and reducing alcohol intake, are associated with a reduction in blood pressure, but their impact on cardiovascular outcomes has not been studied. For those who consume large amounts of alcohol (more than 20 drinks in a week), studies have shown that reduced drinking decreases blood pressure. There is insufficient evidence to recommend single or multiple interventions or to guide the clinician in selecting among nonpharmacological therapies.

Return to Contents

Screening for Lipid Disorders in Adults

Summary of Recommendations The U.S. Preventive Services Task Force (USPSTF) strongly recommends that clinicians routinely screen men aged 35 years and older and women aged 45 years and older for lipid disorders and treat abnormal lipids in people who are at increased risk for coronary heart disease. Rating: A Recommendation. The USPSTF recommends that clinicians routinely screen younger adults (men aged 20 to 35 years and women aged 20 to 45 years) for lipid disorders if they have other risk factors for coronary heart disease. (See Clinical Considerations for a discussion of risk factors.) Rating: B Recommendation. The USPSTF makes no recommendation for or against routine screening for lipid disorders in younger adults (men aged 20 to 35 years or women aged 20 to 45 years) in the absence of known risk factors for coronary heart disease. Rating: C Recommendation. The USPSTF recommends that screening for lipid disorders include measurement of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C). Rating: B Recommendation. The USPSTF concludes that the evidence is insufficient to recommend for or against triglyceride measurement as a part of routine screening for lipid disorders. Rating: I Recommendation.

This USPSTF recommendation was first published in:  Am J Prev Med 2001;20(3S):73-6. http://www.ahrq.gov/clinic/ajpmsuppl/lipidrr.htm.

Clinical Considerations

• TC and HDL-C can be measured on nonfasting or fasting samples.
• Abnormal results should be confirmed by a repeated sample on a separate occasion, and the average of both results should be used for risk assessment. Although measuring both TC and HDL-C is more sensitive and specific for assessing coronary heart disease risk, TC alone is an acceptable screening test if available laboratory services cannot provide reliable measurements of HDL. In conjunction with HDL-C, low-density lipoprotein cholesterol (LDLC) and TC provide comparable information, but measuring LDL-C requires a fasting sample and is more expensive. In patients with elevated risk on screening results, lipoprotein analysis, including fasting triglycerides, may provide information that is useful in choosing optimal treatments.
• Screening is recommended for men aged 20 to 35 years and for women aged 20 to 45 years in the presence of any of the following:
  • Diabetes
  • A family history of cardiovascular disease before age 50 years in male relatives or age 60 years in female relatives.
  • A family history suggestive of familial hyperlipidemia.
  • Multiple coronary heart disease risk factors (e.g., tobacco use, hypertension).
• The optimal interval for screening is uncertain. On the basis of other guidelines and expert opinion, reasonable options include every 5 years, shorter intervals for people who have lipid levels close to those warranting therapy, and longer intervals for low-risk people who have had low or repeatedly normal lipid levels.
• An age to stop screening is not established. Screening may be appropriate in older people who have never been screened, but repeated screening is less important in older people because lipid levels are less likely to increase after age 65 years.
• Treatment decisions should take into account overall risk of heart disease rather than lipid levels alone. Overall risk assessment should include the presence and severity of the following risk factors: age, gender, diabetes, elevated blood pressure, family history (in younger adults), and smoking. Tools that incorporate specific information on multiple risk factors provide more accurate estimation of cardiovascular risk than categorizations based on counting the numbers of risk factors.^16,17
• Treatment choices should take into account costs and patient preferences. Drug therapy is usually more effective than diet alone, but choice of treatment should consider overall risk, costs of treatment, and patient preferences. Guidelines for treating high cholesterol are available from the National Cholesterol Education Program of the National Institutes of Health.¹⁸ Although diet therapy is an appropriate initial therapy for most patients, a minority achieve substantial reductions in lipid levels from diet alone; drugs are frequently needed to achieve therapeutic goals, especially for high-risk people. Lipid-lowering treatments should be accompanied by interventions addressing all modifiable risk factors for heart disease, including smoking cessation, treatment of blood pressure, diabetes, and obesity, as well as promotion of a healthy diet and regular physical activity. Long-term adherence to therapies should be emphasized.
• All patients, regardless of lipid levels, should be offered counseling about the benefits of a diet low in saturated fat and high in fruits and vegetables, regular physical activity, avoiding tobacco use, and maintaining a healthy weight.

Return to Contents

Screening for Peripheral Arterial Disease

Summary of Recommendation The U.S. Preventive Services Task Force (USPSTF) recommends against routine screening for peripheral arterial disease (PAD). Rating: D Recommendation.

This recommendation statement was first published by: Agency for Healthcare Research and Quality, Rockville, MD. August 2005. http://www.ahrq.gov/clinic/uspstf05/pad/padrs.htm.

Clinical Considerations

• The ankle brachial index, a ratio of Doppler-recorded systolic pressures in the lower and upper extremities, is a simple and accurate noninvasive test for the screening and diagnosis of PAD. The ankle brachial index has demonstrated better accuracy than other methods of screening, including history-taking, questionnaires, and palpation of peripheral pulses. An ankle-brachial index value of less than 0.90 (95% sensitive and specific for angiographic PAD) is strongly associated with limitations in lower extremity functioning and physical activity tolerance.
• Smoking cessation and lipid-lowering agents improve claudication symptoms and lower extremity functioning among patients with symptomatic PAD. Smoking cessation and physical activity training also increase maximal walking distance among men with early PAD. Counseling for smoking cessation, however, should be offered to all patients who smoke, regardless of the presence of PAD. Similarly, physically inactive patients should be counseled to increase their physical activity, regardless of the presence of PAD.

Return to Contents
Proceed to Next Section