The ABCs of Primary Cardiovascular Prevention: 2019 Update
Editor's Note: Commentary based on Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2019. [Epub ahead of print].
Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of mortality and morbidity in the US. Despite significant improvement in ASCVD outcomes over the past 4 decades, the burden of ASCVD risk factors remains high. Consequently, death rates from cardiovascular disease rose in 2015 by 1%, the first rise since 1999.
In an effort to control ASCVD risk factors and promote cardiovascular health, the American Heart Association (AHA) provided a definition of ideal cardiovascular health using 7 metrics collectively called "Life's Simple 7". The simple 7 include not smoking, healthy weight, adequate physical activity and balanced healthy diet, as well as achieving target values for cholesterol, blood pressure and blood glucose. A recent AHA report shows that only 17% of US adults have ≥5 of these metrics at ideal levels, however, highlighting an important health gap in primary prevention. The goal of the new AHA/ACC prevention guidelines is to summarize prior recommendations, expert consensus documents, and clinical practice guidelines into one document to address this gap in prevention.
In this review, we summarize the highlights of the 2019 AHA/ACC primary prevention guidelines using a simple, structured "ABCDE" checklist (Figure 1). The goal is to help clinicians implement best practices of primary prevention using a simple framework.
Before discussing the ABCDE checklist, we must highlight three overarching central recommendations. These recommendations, which apply to all ASCVD prevention efforts, are adopting a team-based care approach to control ASCVD risk factors, engaging patients in shared decision-making and addressing social determinants of health to inform optimal implementation of treatment options. Team-based care improves the quality and maintenance of care. It meets patient needs and achieves greater reduction in ASCVD risk and better outcomes compared to usual care. This is especially true in low-resource settings or vulnerable populations. Shared-decision making engages patients in a discussion regarding their ASCVD risk and is more likely to identify and address potential barriers to treatment options.
A Assess Risk
Choosing the best risk-reducing strategy for asymptomatic patients starts with accurate assessment of ASCVD risk. Risk assessment initiates a clinician-patient discussion that continues throughout primary prevention efforts and allows for appropriate identification of patients who may benefit from pharmacotherapy in addition to lifestyle changes. For adults who are 40 to 75 years of age, the new guidelines continue to recommend the routine assessment of traditional ASCVD risk factors as well as estimation of 10-year ASCVD risk using the race- and sex-specific pooled cohort equations (PCE) (I, B-NR).
Given the limitations of population-based risk estimates, estimated ASCVD risk should be interpreted within the context of the patient's individual circumstances. The PCE either significantly overestimates or underestimates ASCVD in about half of individuals in the 5-20% 10-year ASCVD risk range. For example, ASCVD risk is often underestimated in individuals with low socioeconomic status or other risk-enhancing factors not included in the PCE. For individuals with borderline (5% to <7.5%) or intermediate (≥7.5% to <20%) 10-year ASCVD risk requiring further risk stratification, a reasonable approach is to determine whether additional risk-enhancing factors are present (IIa, B-NR). Table 1 lists the ASCVD risk-enhancing factors described in the new guidelines; if present, they should prompt re-classification to a higher ASCVD risk group.
If uncertainty about the reliability of risk estimation for an individual persists, the new guidelines encourage the use of coronary artery calcium (CAC) measurement to guide preventive strategies in adults with intermediate risk or selected patients with borderline risk (IIa, B-NR). CAC is far superior to other subclinical imaging markers or blood-based biomarkers and has well-established discrimination and risk reclassification properties. CAC reliably reclassifies ASCVD risk upwards when scores are ≥100 Agatston units and accurately reclassifies risk downwards with a score equal to zero. CAC measurement is particularly useful in refining ASCVD risk estimates in lower-risk women, adults <45 years of age or ≥75 years of age, and individuals with strong family history but low estimated ASCVD risk.
A Antiplatelet Therapy
Prescribing aspirin for primary ASCVD prevention is no longer based solely on a threshold of estimated ASCVD risk. Rather, a tailored decision to start aspirin should be based on the overall ASCVD risk estimate (inclusive of PCE risk estimate and risk enhancing factors) weighed against the risk of bleeding. It is reasonable to start aspirin in adults age 40 to 70 with high overall ASCVD risk estimate (inclusive of risk-enhancing factors) or at least moderate coronary artery calcium and low risk of bleeding (IIb, A). However, aspirin is not recommended for primary ASCVD prevention if the risk of bleeding is moderately high (III, C-LD). Similarly, aspirin should not be routinely administered for primary ASCVD prevention to individuals >70 years of age given risk of bleeding that outweighs protective benefit in this age group (III, B-R).
B Blood Pressure
Hypertension contributes significantly to ASCVD morbidity and mortality. The recommendations on blood pressure management are adapted from the 2017 guideline for high blood pressure. The current primary prevention guidelines reemphasize the importance of lifestyle modifications as the starting intervention for those with elevated blood pressure and a necessary adjunct to pharmacologic therapy when it is indicated. Non-pharmacological therapy in the form of weight loss, a heart-healthy dietary pattern, sodium reduction, dietary potassium supplementation, and increased physical activity with a structured exercise program and limited alcohol is recommended for all adults with elevated blood pressure or hypertension.
For adults with an average blood pressure of ≥130/80 mmHg who either have an estimated 10-year ASCVD risk ≥10%, diabetes, or chronic kidney disease, antihypertensive medications are recommended to target a blood pressure goal of <130/80 mmHg. Adults with an estimated 10-year ASCVD risk of <10% and an average blood pressure ≥140/90 mmHg are also recommended antihypertensive medications to lower their blood pressure to <130/80 mmHg. For individuals with a 10-year ASCVD risk of <10% and average blood pressure 130-139/80-89 mmHg, non-pharmacological therapy should be emphasized.
Elevated serum cholesterol is a modifiable primary cause of ASCVD. Recommendations on cholesterol management for primary ASCVD prevention were adapted from the 2018 AHA/ACC Multi-society guidelines on the management of blood cholesterol. In the majority of adults between age 40 and 70 years, estimating 10-year ASCVD risk using PCE is the initial step to guide the clinician-patient discussion regarding statin therapy. The exceptions are in adults with diabetes (I, A) or low-density lipoprotein cholesterol (LDL-C) ≥190 mg/dL (I, B-R), for whom statin therapy is recommended regardless of estimated ASCVD risk.
For adults with intermediate (≥7.5% to <20%) or high (≥20%) 10-year ASCVD risk, a moderate-intensity statin is recommended after a clinician-patient risk discussion (I, A). For those with intermediate ASCVD risk in whom the value of statin therapy remains uncertain, identifying risk-enhancing factors (Table 1; IIa, B-R) or CAC measurement (IIa, B-NR) is reasonable to guide shared decision making. A CAC score ≥100 Agatston units (or ≥75th percentile for age and sex) reliably reclassifies risk upward favoring starting moderate-intensity statin therapy. A CAC score of zero down-classifies risk and favors withholding statins and postponing risk assessment for 5-10 years in those without high risk conditions such as diabetes, family history of premature coronary artery disease, or cigarette smoking (IIa, B-NR).
For adults with borderline 10-year ASCVD risk (5% to <7.5%), the presence of risk-enhancing factors would favor starting moderate-intensity statins (IIb, B-R). In young adults 20-39 year of age, measuring risk factors facilitates calculation of lifetime risk and can help prioritize a healthy lifestyle. Statins in young adults are only strongly recommended for those with LDL-C ≥190 mg/dL or for selected patients with LDL-C persistently ≥160 mg/dL.
C Cigarette Smoking
Tobacco use is the number one modifiable risk factor for morbidity and mortality in the US. Tobacco use status should be assessed at every health care encounter (I, A) and all adults who use tobacco should be firmly advised to quit (I, A). Clinicians should recommend a combination of behavioral and pharmacotherapy to assist quitting (I, A). Seven pharmacological options are now FDA-approved to facilitate tobacco cessation: 5 types of nicotine replacement as well as bupropion and varenicline (see Figure 2).
Figure 2: FDA approved cessation medications and their dosing
The guidelines highlight the fact that neuropsychiatric adverse events are no longer listed as a black box warning for bupropion and varenicline. The benefit of behavioral and/or pharmacotherapy is well established in non-pregnant adults. In pregnant women, the benefit of tobacco cessation is substantial. However, data on the outcomes and safety of pharmacotherapy are still lacking in pregnant women.
Electronic Nicotine Delivery Systems (e.g., e-cigarettes) are not recommended since the safety profile and evidence of benefit are not yet clear. Tobacco use dependence is a chronic disease requiring long-term management. Training health care workers in tobacco treatment increases success in helping their patients quit. Healthcare systems with individual staff dedicated to tobacco treatment have better smoking cessation rates.
Tobacco Treatment Specialists are highly qualified professionals who have the skills, knowledge and training to provide evidence-based interventions to smokers. It is reasonable to have a tobacco treatment specialist at every health care system (IIa, B-R). Second hand smoking remains a preventable cause of death and physicians should advise patients to avoid any level of second hand smoking (including Electronic Nicotine Delivery Systems) (III, B-NR).
Type 2 diabetes mellitus (T2DM) is a prevalent disease and a major ASCVD risk factor. All adults with type 2 diabetes are recommended to follow a tailored heart-healthy nutritional plan to improve glycemic control and weight loss (I, A). Observational data support the use of Mediterranean, DASH, and vegetarian/vegan diets to improve weight and glycemic index. Often, establishing a comprehensive nutritional plan requires a team approach and assistance from a registered dietitian-nutritionist or diabetes education program. Data from cohort studies show a strong association between physical activity and lower rates of CVD events and CVD death. Individuals with diabetes should be recommended at least 150 min of moderate intensity physical activity or 75 min of vigorous-intensity physical activity to assist with weight loss and glycemic control (I, A). A combination of aerobic and resistance training is better than either alone.
Metformin remains first line therapy for patients with T2DM due to its favorable effect on weight loss, glycemic control, and ASCVD outcomes, as well as its low cost and safety profile (IIa, B-R). In patients with T2DM and other ASCVD risk factors who require additional glucose lowering, sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucagon-like peptide (GLP)-1 receptor agonists are now considered reasonable options to reduce cardiovascular disease risk (IIb, B-R).
This is an important new addition since the last guidelines. Three randomized controlled trials showed significant reduction in ASCVD events and heart failure admissions or exacerbations as well as improvement in hemoglobin A1c, body weight, and blood pressure control with SGLT-2 inhibitors. For those with high ASCVD risk, GLP-1 receptor agonists have a similar beneficial effect on ASCVD outcomes.
D Diet and Weight
Diet and nutrition have an important impact on ASCVD risk factors. To decrease ASCVD risk, a diet rich in vegetables, fruits, legumes, nuts, whole grains, and fish is recommended (I, B-R). Intake of trans and saturated fats should be avoided (III, B-NR). Reducing dietary cholesterol and salt and replacing saturated fat with dietary monounsaturated and polyunsaturated fats is reasonable for those interested in reducing their ASCVD risk (IIa, B-NR). Similarly, minimizing intake of processed meat, refined carbohydrates, and sweetened beverages is a reasonable option to reduce ASCVD risk (IIa, B-NR).
To address the rising epidemic of overweight and obesity, the 2019 prevention guidelines highlight the importance of identifying those at risk and focusing on lifestyle recommendations for weight loss. Calculating the body mass index (BMI) to identify adults with overweight (BMI of 25 to 29.9 kg/m2) or obesity (BMI ≥30 kg/m2) is recommended at least annually (I, C-EO).
Measuring waist circumference during office visits is reasonable to identify those with central adiposity and high cardiometabolic risk (IIa, B-NR). For those with overweight and obesity, weight loss is recommended (I, B-R) to reduce ASCVD risk and improve other ASCVD risk factors. To achieve weight loss, comprehensive lifestyle intervention and counseling is recommended (I, B-R). This includes regular self-monitoring of food intake, physical activity, and weight. Reducing daily caloric intake by >500 kCal/day from baseline and increasing physical activity to >150 min of brisk activity per week are reasonable for initial intervention.
Exercise and physical activity are important lifestyle factors affecting ASCVD risk. Therefore, routinely counseling patients on ways to optimize their physical activity is recommended (I, B-R). Healthcare providers should encourage adults to engage in at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise weekly (I, B-NR). In those who are not able to achieve this minimum recommended duration, engaging in any duration of moderate-to-vigorous exercise should be promoted as some reduction of ASCVD risk is likely (IIa, B-NR). In addition to dedicating time for exercise, the new guidelines also highlight the importance of avoiding sedentary behavior during the remainder of the day (IIb, C-LD). Avoiding sedentary behavior is especially important for those achieving the least amount of moderate-to-vigorous intensity exercise.
E Economic and Social Factors
Economic and social inequalities are important determents of CVD risk and failing to address socioeconomic factors may limit the effectiveness of prevention recommendations. Socioeconomic disadvantages are not captured by existing CVD risk equations. Therefore, clinicians should routinely explore barriers to following therapy recommendations and tailor advice to individual patient circumstances (I, B-NR). Medicare/Medicaid developed a screening tool to identify socioeconomic determinants of health based on 5 domains: housing instability, food insecurity, transportation difficulties, utility assistance needs, and interpersonal safety.
Each should be identified and addressed while formulating a prevention plan. Financial strain, inadequate housing conditions and unsafe neighborhoods are other important determinants of cardiovascular health which should be considered. Individuals with poor health literacy or comorbid mental illness may need more time to discuss ASCVD prevention.
The burden of ASCVD and ASCVD risk factors remains high. Therefore, there is a great need for the effective implementation of best practices in primary prevention to reduce ASCVD burden. The ABCDE checklist provides a simple yet comprehensive framework to address the most up-to-date primary prevention recommendations.
Clinical Topics: Diabetes and Cardiometabolic Disease, Dyslipidemia, Heart Failure and Cardiomyopathies, Prevention, Atherosclerotic Disease (CAD/PAD), Lipid Metabolism, Nonstatins, Novel Agents, Statins, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Diet, Exercise, Hypertension, Smoking
Keywords: Dyslipidemias, Antihypertensive Agents, Aspirin, Atherosclerosis, Blood Glucose, Blood Pressure, Biomarkers, Pharmacological, American Heart Association, Body Weight, Body Mass Index, Cardiovascular Diseases, Calcium, Adiposity, Bupropion, Cholesterol, Dietary, Cholesterol, LDL, Chronic Disease, Complement Factor B, Cohort Studies, Coronary Artery Disease, Diabetes Mellitus, Diabetes Mellitus, Type 2, Drug Labeling, Exercise, Exercise Therapy, Energy Intake, Fabaceae, Food Supply, Glucagon-Like Peptide 1, Glucagon-Like Peptides, Glucose, Glycemic Index, Health Literacy, Heart Failure, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Hypertension, Medicaid, Medicare, Nicotine, Metformin, Nutritionists, Obesity, Overweight, Pregnancy, Potassium, Dietary, Primary Prevention, Renal Insufficiency, Chronic, Reproducibility of Results, Risk Assessment, Risk Factors, Sedentary Lifestyle, Smoking, Smoking Cessation, Social Class, Social Determinants of Health, Socioeconomic Factors, Sodium, Sodium-Glucose Transport Proteins, Sweetening Agents, Tobacco, Tobacco Use Cessation, Tobacco Smoke Pollution, Diet, Vegetarian, Vulnerable Populations, Waist Circumference, Weight Loss
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