2014 Hot Topic: Implementation of the New ACC/AHA Prevention Guidelines

The ACC/AHA recently published four sets of prevention guidelines, including the Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults,1 Guideline on Lifestyle Management to reduce Cardiovascular Risk,2 Guideline for the Management of Overweight and Obesity in Adults,3 and the Guideline on the Assessment of Cardiovascular Risk.4 These guidelines began in 2008 as an update to the ATP III guidelines and in collaboration with the NHLBI, they were transitioned to the ACC/AHA in June 2013 and then published in November of 2013. These guidelines were designed to answer specific clinical questions, and only randomized clinical controlled trials published between 1995 and 2011 were utilized. While these guidelines advocate obtaining specific data such as BMI and waist circumference as outlined in the obesity guidelines, they also provide an important opportunity to have patient specific conversations about risk and treatment.

Blood Cholesterol Guidelines

The shift away from LDL-C cholesterol goals and the predominant use of statins as the foundation for treatment of risk are the largest changes in the new guidelines. Only trials that showed cardiovascular risk reduction were included in the recommendations. Four groups that showed benefit were defined as the risk groups most likely to benefit from treatment with at statin. These include, those with evidence of atherosclerotic cardiovascular disease (ASCVD), those individuals >21 years of age and LDL-C ≥ 190 mg/dL, patients with diabetes aged 40-75 with LDL-C 70-189 mg/dL and patients without diabetes and Pooled Cohort Risk Assessment of ≥ 7.5% and LDL-C 70-189 mg/dL. The decision to treat, particularly in primary prevention should be a shared decision between the clinician and the patient. While this does increase the burden on the clinician in regards to time, the shared decision will better inform the patient about risks and benefits of treatment and may improve long term adherence to therapy.

There are other at risk individuals who are not included in the four risk groups and require a patient clinician discussion as to the potential role of therapy. For example, the guidelines point out that it is reasonable to treat primary prevention individuals with LDL-C <190 mg/dL and a 10 year pooled risk of 5-7.5% with moderate dose statin. But a discussion of the risks and benefits with the patient is essential. If the clinician is uncertain about risk, other factors such as family history of premature ASCVD, elevated lifetime risk of ASCVD, LDL-C > 160 mg/dL, high-sensitivity C-reactive protein ≥ 2 mg/L, coronary calcium score ≥ 300 Agatston units or > 75% for age, sex and ethnicity, or ankle-brachial index < 0.9 can be used to inform the discussion about the role of statin therapy. There were groups identified that lacked data for the panel to make recommendations regarding initiation or discontinuation in patients and included patients with heart failure or who are on chronic hemodialysis.

The role of non-statin therapy has been minimized in these new guidelines, and is limited to high risk individuals such as those with familial hyperlipidemia, those intolerant to statin therapy, or those who do not achieve adequate reduction with statin therapy. The addition of a non-statin therapy to further reduce risk in these individuals may be undertaken with the knowledge of the risks and benefits of combination therapy.

Lipids should be checked when therapy is initiated and then periodically afterwards to assess effectiveness of medication and medication and lifestyle adherence. Lipids should be checked to be sure that an adequate response to moderate dose statins (>30% reduction in LDL) or high dose statins (>50% reduction) has been achieved. If these levels have not been achieved, then patient barriers to compliance should be assessed and addressed. In some patients, particularly with familial hyperlipidemia, the response to statins is varied and despite excellent compliance, inadequate LDL reductions occur. Non-statin therapy can be considered in these individuals.

For clinicians and patients who have grown accustomed to treating to targets and "knowing their numbers", these new guidelines are a significant departure and will take some getting used to. Additionally, many of the metrics used to assess physician performance are tied to cholesterol targets and will need to adapt. As new studies, particularly non statin studies are published, the guidelines will adapt and so will our discussions with our patients.

Risk Prediction

Previous guidelines utilized the Framingham Risk Score for risk stratification. To broaden the risk prediction model, three additional cohorts were included in an effort to broaden its applicability. The risks of fatal and nonfatal myocardial infarction as well as the risk of fatal and nonfatal stroke were included in the new ASCVD Risk Estimator (can we put in link/link to app). In addition to 10-year risk, a lifetime risk of atherosclerotic cardiovascular disease is calculated. While the Blood Cholesterol guidelines do not target therapy for a specific lifetime risk, the score can be used both to motivate individuals to adhere to lifestyle modifications and to help refine individual risk in the risk discussion with the patient. The new risk calculator also has separate equations for African-American patients who are at higher risk for stroke. The calculator may however underestimate the risk for Asian Americans particularly of south Asian ancestry and overestimate the risk for Asian Americans of east Asian ancestry.

Lifestyle Management

The core of all atherosclerotic risk reduction is lifestyle modification and should be included in the risk assessment and risk reduction discussion with each patient. The Guideline of Lifestyle Management to Reduce Cardiovascular risk highlighted dietary and activity goals for prevention. No specific dietary pattern was recommended, but the DASH dietary pattern, USDA Food Pattern and the AHA Diet each meet the goals whereas the previously endorsed low-fat diet does not. A diet rich in fruits, vegetables, whole grains with protein from low fat dairy, fish, legumes and poultry is recommended with saturated fat limited to 5-6% of caloric intake. For blood pressure control, limiting sodium intake to 2400 mg per day is recommended with improved blood pressure reduction with 1500 mg daily. Even a reduction of 1000 mg per day can reduce blood pressure and cardiovascular events and should be the minimum goal for individuals to reduce risk.

Physical activity to reduce LDL-C, non-HDL-C and blood pressure is also recommended with the goal of 3 to 4 sessions per week lasting on average 40 minutes per session. The activity should be moderate-to-vigorous in intensity.

Obesity Guidelines

The increased cardiovascular risk and risk for all cause mortality in patients with obesity should be highlighted and the benefits of weight reduction reinforced at patient-clinician interactions. At least annual measurement of height, weight, BMI and waist measurement can identify those with elevated risk and provide an opportunity for risk reduction discussion. Patients should understand that a modest weight loss of 3-5% can result in clinically meaningful reductions in glucose, triglycerides and the development of diabetes. Greater amounts of weight loss will result in improved LDL-C, HDL-C levels, and blood pressure. As part of a comprehensive lifestyle intervention, clinicians should prescribe reduced calorie intake which is typically 1200-1500 kcal/day for women and 1500-1800 kcal/day for men. These represent an energy deficit of 500-750 kcal/day or a 30% energy deficit and should result in weight loss. Referral to a nutrition professional for counseling is given a strong recommendation. Also recommended for overweight and obese individuals who could benefit from weight loss is participation in at least 6 months of a high-intensity (≥ 14 sessions in 6 months) lifestyle program that includes increased physical activity and reduced caloric intake. Bariatric surgery may be appropriate for individuals with BMI ≥ 40 or BMI ≥ 35 with obesity related comorbidities who have inadequate response to lifestyle programs with or without pharmacotherapy.

Clinician-Patient Interaction

Four prevention guidelines have been published to assist in the reduction of atherosclerotic cardiovascular disease. Each has been designed to answer specific clinical questions that can help assist in patient care. While the data is not complete to answer each patient's individual needs and risk, they provide an opportunity for the clinician to have an informed discussion with the patient to maximize patient involvement, understanding and ultimately long term compliance with risk reduction measures for long-term health.


References

  1. Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 AHA/ACC 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. J Am Coll Cardiol 2013; [Epub Ahead of Print].
  2. Eckel RH, Jakicic JM, Ard JD, et al. 2013 AHA/ACC Guideline on Lifestyle Management to Reduce Cardiovascular Risk: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013; [Epub Ahead of Print].
  3. Jensen MD, Ryan DH, Apovian CM, et al. 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Obesity Society 2013; [Epub Ahead of Print].
  4. Goff DC Jr, Lloyd-Jones DM, Bennett G, et al. 2013 AHA/ACC Guideline on the Assessment of Cardiovascular Risk: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013; [Epub Ahead of Print].

Clinical Topics: Dyslipidemia, Nonstatins, Novel Agents, Statins

Keywords: Atherosclerosis, Cardiovascular Diseases, Hydroxymethylglutaryl-CoA Reductase Inhibitors, National Heart, Lung, and Blood Institute (U.S.)


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