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Atherosclerotic Cardiovascular Disease Risk: Assessment and Management

Atherosclerotic Cardiovascular Disease Risk: Assessment and Management

White Paper

Atherosclerotic Cardiovascular Disease Risk: Assessment and Management

 

Contents:

New ACC/AHA Guidelines Introduced

Differences Between 2013 Guidelines and Previous Guidelines

Statin Benefit Groups and Therapy Intensities - Table 1 - Figure

10-Year ASCVD Risk Calculation

Quest Diagnostics ASCVD Risk Panels - Table 2

Additional Reading

References
 

 

New ACC/AHA Guidelines Introduced [return to contents]

In November 2013, the American College of Cardiology (ACC) and the American Heart Association (AHA) released guidelines related to the assessment and management of atherosclerotic cardiovascular disease (ASCVD) risk in adults. These guidelines were initiated by the National Heart, Lung, and Blood Institute (NHLBI), which convened expert groups in 2008 and transferred responsibility for generating recommendations to the ACC and AHA in 2013. The resulting set of 4 guidelines addressed ASCVD risk assessment, treatment of blood cholesterol, lifestyle management, and overweight and obesity management. This White Paper is intended to help the reader become acquainted with 2 of these guidelines: ASCVD risk assessment1 and treatment of blood cholesterol to reduce ASCVD risk.2 This Paper will also acquaint the reader with 2 test panels that facilitate implementation of the guidelines.

Differences Between 2013 Guidelines and Previous Guidelines [return to contents]

The 2013 guideline related to treatment was intended to be the next iteration of the Adult Treatment Panel III (ATP III) guidelines, which were last updated in 2004. Thus, the anticipated guidelines were sometimes referred to as ATP IV and were expected to provide a comprehensive approach to the management of lipid disorders, as ATP III did. However, the published version is not a comprehensive approach to lipid management; thus, it does not address many questions related to complex lipid disorders. Instead, the guideline has a narrower scope and only addresses lipid management as it pertains to reduction of ASCVD risk.2

The 2013 ACC/AHA guidelines recommend 2 primary changes in risk assessment and treatment of ASCVD. Previous guidelines focused on treating to target cholesterol levels, but the 2013 guidelines focus instead on using the appropriate intensity of statin therapy to treat patients who are likely to benefit. In addition, previous guidelines recommended using Framingham-based risk scores to assess ASCVD risk, but the 2013 guidelines describe and recommend a new tool for calculating risk: the Pooled Cohorts Equations.

Statin Benefit Groups and Therapy Intensities [return to contents]

The Blood Cholesterol Expert Panel conducted a systematic review of randomized controlled trials with ASCVD outcomes and concluded that the focus of blood cholesterol treatment should shift. ATP III had recommended using specific LDL cholesterol (LDL-C) and/or non-HDL cholesterol treatment targets. However, the Expert Panel did not find sufficient randomized controlled trial evidence to support use of cholesterol treatment targets. The Expert Panel instead found evidence that the appropriate intensity of statin therapy reduces ASCVD risk. Thus, the 2013 ACC/AHA guideline on treatment recommends using different intensities of statin therapy to treat individuals who are likely to benefit.

The new treatment guideline identifies 4 major patient groups that are likely to benefit from statin therapy. These groups are based on evidence that statin therapy can help prevent primary and secondary ASCVD events, except in individuals with NYHA class II-IV heart failure and those who are receiving hemodialysis. The 4 groups are defined by patient characteristics, including clinical ASCVD status, age, LDL-C levels, diabetes status, and 10-year ASCVD risk estimate. Table 1 shows the patient characteristics of the 4 statin benefit groups.

Table 1. Statin Benefit Groups

Patient Characteristics

Clinical ASCVDa  and age 21-75 years

LDL-C ≥190 mg/dL and age ≥21 years

Diabetes and

  • LDL-C 70-189 mg/dL

  • No clinical ASCVD

  • Age 40-75 years

10-year ASCVD risk ≥7.5%b

  • LDL-C 70-189 mg/dL

  • No clinical ASCVD or diabetes

  • Age 40-75 years

ASCVD, atherosclerotic cardiovascular disease; y, years.
a Clinical ASCVD includes acute coronary syndromes or a history of stroke, transient ischemic attack, myocardial infarction, arterial revascularization, stable or unstable angina, or peripheral arterial disease of atherosclerotic origin.
b Use of the Pooled Cohort Equations is recommended when estimating 10-year ASCVD risk. Estimates are based on African American and non-Hispanic white cohorts; an estimate based on the non-Hispanic white cohort can be used for other ethnicities.1

In patients likely to benefit from statin therapy, the intensity of therapy should correspond to the degree of ASCVD risk. The guideline on treatment identifies 3 levels of therapy: high-intensity (lowering LDL-C by approximately 50%), moderate-intensity (lowering LDL-C by approximately 30% to 50%), and low-intensity (lowering LDL-C by <30%). Statin therapy intensity is classified according to the percent reduction in LDL-C levels, because the degree by which LDL-C is lowered correlates with the degree of ASCVD risk reduction. Thus, monitoring LDL-C levels can confirm patient adherence and the expected effect of treatment. The Figure shows the recommended statin therapy intensities based on patient characteristics. Consult the treatment guideline2 for specific statins and doses that correspond to statin therapy intensities.

Figure. Determining Intensity of Statin Therapy for ASCVD Risk Reductiona

10-Year ASCVD Risk Calculation [return to contents]

The 2013 ACC/AHA treatment guidelines2 recommend use of the Pooled Cohort Equations for calculating 10-year ASCVD risk (defined as nonfatal myocardial infarction, coronary heart disease death, and fatal and nonfatal stroke). The Equations were developed by the Risk Assessment Work Group and published in the 2013 ACC/AHA guideline on risk assessment.1 Although ATP III had recommended estimating 10-year risk for CHD using a Framingham-based scoring system, the Work Group decided that the system suffered from 2 major drawbacks: derivation from an exclusively white population and a narrow focus on one outcome: ie, hard CHD. The Pooled Cohort Equations are derived from community-based cohorts that are representative of white and African American populations in the US. They also focus on outcomes considered more relevant to physicians and patients: first hard ASCVD event (CHD death, nonfatal myocardial infarction, or fatal or nonfatal stroke).

The Work Group also found that other risk calculations (eg, Reynolds Risk Score, PRO-CAM, QRISK) included risk factors that showed promise but were based on limited data. Thus, the following risk factors are not incorporated into the new risk estimate calculations: family history of premature cardiovascular disease, lifetime ASCVD risk, high sensitivity C-reactive protein, coronary artery calcium, and ankle brachial index. The guidelines do stipulate that these factors may be considered if a risk-based treatment decision is uncertain.

The Pooled Cohort Equations can be used to calculate the 10-year ASCVD risk estimate and the 10-year ASCVD risk goal for individuals 40 to 79 years of age. The 10-year ASCVD risk estimate is based on an individual’s sex, age, race, systolic blood pressure, total and HDL cholesterol levels, and diabetes, smoking, and high blood pressure treatment status. It can help a physician choose the appropriate statin therapy in patients who have LDL-C levels of 70-189 mg/dL but do not have clinical ASCVD. The lifetime ASCVD risk estimate and lifetime ASCVD risk goal for patients between 20 and 59 years old can also be calculated using the Equations; the lifetime ASCVD risk estimate can assist a physician when a risk-based treatment decision is uncertain.

The 2013 ACC/AHA treatment guideline recommends recalculating the 10-year risk estimate every 4 to 6 years in individuals who are not receiving cholesterol-lowering drug therapy, are aged 40 to 75 years, have LDL-C 70 to 189 mg/dL, and lack clinical ASCVD and diabetes.2 An online ASCVD risk calculator can be accessed at http://my.americanheart.org/cvriskcalculator.

Quest Diagnostics ASCVD Risk Panels [return to contents]

Quest Diagnostics offers 2 panels that include calculation of ASCVD risks:

  1. ASCVD Risk Panel with Score (test code 92053)

  2. Cardio IQ™ ASCVD Risk Panel with Score (test code 92052)

Table 2 summarizes the components of both ASCVD risk panels. Some panel components can be ordered separately, without risk calculations; see the Appendix.

Table 2. Components of ASCVD Risk Panelsa
Test Results
     Cholesterol, Total
     Triglyceridesb
     HDL Cholesterol
     LDL Cholesterol
     Cholesterol/HDL Ratio
     Non-HDL Cholesterol
ASCVD Risks
     10-year risk estimate for ages 40-79
     10-year risk goal for ages 40-79
     Lifetime risk estimate for ages 20-59
     Lifetime risk goal for ages 20-59
Risk calculations require the following patient information at time of order entry:
     Age In years
     Gender Male or Female
     Race—African American Yes or No
     Systolic blood pressure In mm Hg
     Treatment for high blood pressure Yes or No
     Diabetes status Yes or No
     Smoking status Yes or No

a Some panel components can be ordered separately, without risk calculations; see Appendix.
b If result is >400 mg/dL, a direct LDL cholesterol test will be performed at an additional charge.

The report includes reference ranges and the patient’s results for each of the lipid panel components. HDL and total cholesterol concentrations are combined with provided patient information to calculate patient-specific ASCVD risk estimates:

  1. 10-year ASCVD risk estimate: can be used to assess ASCVD risk and help choose the recommended intensity of statin therapy

    • <5% indicates low risk

    • 5% to <7.5% indicates moderate risk

    • ≥7.5% indicates elevated risk

  2. 10-year ASCVD risk goal: target risk score, based on patient age, gender, race, and optimal risk factor levels

  3. Lifetime ASCVD risk estimate: can guide treatment decisions when the benefit of statin therapy for ASCVD prevention is uncertain

  4. Lifetime ASCVD risk goal: target risk score, based on patient gender and optimal risk factor levels for someone at age 50.

The Cardio IQ version of the ASCVD risk panel provides a special report that includes color-coded risk categories, comparison of current results to previous results, and a graphic display of lipid subclass distribution (when ordered) to aid patient education, in addition to other features. The Cardio IQ test is not available for patients under 20 years of age.

Additional Reading [return to contents]

The ACC/AHA 2013 guidelines on treatment have spawned considerable debate that is beyond the scope of this document. For additional information about the guidelines and the debate, please refer to references 3, 4, and 5.

References [return to contents]

  1. Goff DC, Lloyd-Jones DM, Bennett G, et al. 2013 ACC/AHA guideline on the assessment of cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(suppl 2):S49-S73.

  2. Stone NJ, Robinson J, Lichtenstein, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(suppl 2):S1-S45.

  3. Guallar E, Laine C. Controversy over clinical guidelines: listen to the evidence, not the noise. Ann Intern Med. 2014;160:361-362.

  4. Martin SS, Blumenthal RS. Concepts and controversies: the 2013 American College of Cardiology/American Heart Association risk assessment and cholesterol treatment guidelines. Ann Intern Med. 2014;160:356-358.

  5. Stone NJ, Robinson JG, Lichtenstein AH, et al. Treatment of blood cholesterol to reduce atherosclerotic cardiovascular disease risk in adults: synopsis of the 2013 ACC/AHA cholesterol guideline. Ann Inter Med. 2014;160:339-343.
     

Appendix. Individual Test Code Options for Panel Components
Test Code

Test Name

91716

Cardio IQ Lipid Panel
Includes cholesterol/HDL ratio, HDL cholesterol, LDL and non-HDL cholesterol (both calculated), total cholesterol, and triglycerides, and a Cardio IQ interpretive report.

91717

Cardio IQ Cholesterol, Total

91718

Cardio IQ Triglycerides

91719

Cardio IQ HDL Cholesterol

7600

Lipid Panel
Includes cholesterol/HDL ratio, HDL cholesterol, LDL and non-HDL cholesterol (both calculated), total cholesterol, and triglycerides.

334

Cholesterol, Total

896

Triglycerides

608

HDL Cholesterol

 Content reviewed 12/2014
 

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