Atherosclerotic cardiovascular disease risk assessment for primary prevention in adults

INTRODUCTION — 

Cardiovascular disease is the leading cause of global mortality and a major cause of morbidity [1,2]. Coronary heart disease is the most common manifestation of cardiovascular disease and globally causes approximately half of cardiovascular deaths [2].

Atherosclerotic cardiovascular disease (ASCVD) is the subset of cardiovascular disease caused by atherosclerosis. As a diagnostic category, it includes four major areas:

●Coronary heart disease manifested by fatal or nonfatal myocardial infarction and angina pectoris

●Cerebrovascular disease manifested by ischemic stroke and transient ischemic attack

●Peripheral artery disease manifested by intermittent claudication and critical limb ischemia

●Aortic atherosclerosis, including thoracic or abdominal aortic aneurysm

This topic will review which adults without ASCVD should undergo ASCVD risk assessment, the approach to assessing risk, and the implications of the estimated risk on preventive strategies. The overall approach and rationale for risk factor modification, specific characteristics of risk calculators for formal risk estimation, and the management of various risk factors are discussed separately:

●(See "Overview of primary prevention of cardiovascular disease in adults".)

●(See "Cardiovascular disease risk assessment for primary prevention: Risk calculators".)

●(See "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease", section on 'Indications for statin therapy'.)

●(See "Aspirin in the primary prevention of cardiovascular disease and cancer".)

How to identify, evaluate, and manage cardiovascular risk in children and adolescents is also discussed separately. (See "Overview of pediatric risk factors for premature atherosclerotic cardiovascular disease (ASCVD)" and "Pediatric prevention of adult cardiovascular disease: Promoting a healthy lifestyle and identifying at-risk children" and "Dyslipidemia in children and adolescents: Definition, screening, and diagnosis".)

TERMINOLOGY

●ASCVD risk assessment – In this topic, "ASCVD risk assessment" refers to a comprehensive clinical evaluation that includes the identification of traditional ASCVD risk factors and "risk enhancers" and, for most adults, ASCVD risk estimation.

●ASCVD risk estimation – "ASCVD risk estimation" refers to the quantitative calculation of 10- or 30-year ("lifetime") ASCVD risk using a validated risk calculator.

IDENTIFY RISK FACTORS — 

We discuss ASCVD risk and initiate the process of risk assessment in all adults beginning at age 20 or with their first health care encounter after that age. We start by identifying traditional risk factors, including serum lipid levels, and risk-enhancing factors.

Traditional risk factors — We use the history and physical examination to determine whether the patient has any traditional risk factors for ASCVD (algorithm 1). These include major risk factors that are usually included in ASCVD risk calculators, such as cigarette smoking, hypertension, diabetes mellitus (DM), dyslipidemia, and obesity. As part of risk factor identification, we check a baseline lipid profile that includes measurements of triglycerides and total, high-density lipoprotein, and low-density lipoprotein (LDL) cholesterol (see "Screening for lipid disorders in adults"). We additionally assess diet and level of physical activity to formulate a comprehensive picture of the patient's overall cardiovascular risk and identify potential opportunities for lifestyle changes.

Periodic risk assessment offers the opportunity to identify ASCVD risk factors and offer guidance on the appropriate management [3]. It is also the first step in determining the level of ASCVD risk for individual patients and helping them to prioritize ASCVD risk reduction. The overall approach to and rationale for risk factor identification and modification for the primary prevention of ASCVD and detailed information about specific risk factors are discussed separately (see "Overview of primary prevention of cardiovascular disease in adults"):

●Cigarette smoking (see "Cardiovascular risk of smoking and benefits of smoking cessation")

●Diabetes mellitus (see "Clinical presentation, diagnosis, and initial evaluation of diabetes mellitus in adults", section on 'Diagnostic criteria')

●Hypertension (see "Overview of hypertension in adults", section on 'Definitions')

●Hyperlipidemia, including known familial hyperlipidemia or an individual history of elevated total cholesterol or LDL cholesterol (see "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease")

●Obesity (see "Obesity in adults: Prevalence, screening, and evaluation")

●Diet (see "Healthy diet in adults")

●Physical activity (see "Exercise and fitness in the prevention of atherosclerotic cardiovascular disease")

Risk-enhancing factors — We evaluate for the presence of risk-enhancing factors and include them in the overall ASCVD risk assessment (table 1). Risk-enhancing factors are ASCVD risk factors that are not included in some or all ASCVD risk calculators. At the population level, some of these risk-enhancing factors may not independently predict ASCVD risk or improve risk assessment models [4]. However, they may increase an individual's risk of future ASCVD events and can inform ASCVD risk discussions, especially when uncertainty exists about the utility of primary prevention strategies [4-6]. As an example, a family history of premature ASCVD is not included in some ASCVD risk calculators (eg, the Predicting Risk of cardiovascular disease EVENTs [PREVENT] calculator) and does not improve the performance of some ASCVD risk models [7]. However, a well-documented family history of premature ASCVD may help inform discussion and management of an individual's ASCVD risk.

For adults with diabetes, several additional ASCVD risk enhancers have been identified. These include long duration (≥10 years for type 2 DM or ≥20 years for type 1 DM), albuminuria (≥30 mcg albumin/mg creatinine), chronic kidney disease (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73), retinopathy, and neuropathy [4].

Certain risk calculators include some of these risk-enhancing factors, which enables clinicians to incorporate them into quantitative risk estimates. As an example, the QRISK3 calculator, derived with data from adults in the United Kingdom, includes the presence of autoimmune disease, and the PREVENT calculator has measures of kidney function, such as eGFR and albuminuria. Risk-enhancing factors that are not included in the selected risk calculator can be used to qualitatively adjust the level of ASCVD risk for a given individual.

The 30-year predictive values of the risk-enhancing factors high-sensitivity C-reactive protein and lipoprotein(a) are discussed below and in detail separately. (See 'When to estimate 30-year ("lifetime") risk' below and "C-reactive protein in cardiovascular disease" and "Lipoprotein(a)".)

ASCVD RISK ASSESSMENT — 

We use the results of risk factor identification to develop an overall picture of the patient's risk for ASCVD events and determine whether additional risk stratification is needed (see 'Terminology' above). Additional ASCVD risk stratification typically includes quantitative estimation of the patient's ASCVD risk using a risk calculator and depends primarily on the patient's age and identified cardiovascular risk factors. This approach is discussed below (algorithm 1). It is generally consistent with recommendations from the American Heart Association (AHA) and American College of Cardiology (ACC) [5,7].

We do not perform ASCVD risk assessment for primary prevention in adults with established ASCVD (eg, atherosclerotic coronary artery disease, cerebrovascular atherosclerotic disease, or peripheral arterial disease). Such patients are at high risk of recurrent cardiovascular events and should be treated with appropriate secondary prevention measures. (See "Prevention of cardiovascular disease events in those with established disease (secondary prevention)".)

Patients ages 20 to 29 years — For patients between ages 20 and 29 years, we clinically assess the lifetime risk of ASCVD and identify individuals at high ASCVD risk. We do not routinely use an ASCVD risk calculator to perform quantitative risk estimates in these patients [8]. Although risk calculation may be appropriate for selected young adults with one or more ASCVD risk factors, estimation of the absolute risk of ASCVD is especially challenging in this age group [9].

●Assess lifetime ASCVD risk – For individuals in this age range, we focus on the qualitative assessment of the lifetime risk of ASCVD because this may help some patients prioritize lifestyle changes for ASCVD risk reduction [5,10]. The assessment of lifetime risk should include an evaluation of traditional risk factors, lipid panel results, and risk-enhancing factors (see 'Identify risk factors' above). Because atherosclerosis begins early in life, early risk assessment and intervention may be the most effective strategy for reducing the incidence of ASCVD, especially at the population level [11].

We typically do not perform 10- or 30-year ASCVD risk calculations in these patients. Ten-year risk is typically extremely low in most of these individuals, and data are scarce regarding the utility of 10- and 30-year risk estimates and the impact of interventions to reduce the future risk of clinical outcomes in young, low-risk populations [5]. Guidelines from the United States and Europe offer different approaches to ASCVD risk estimation in this group of patients [5,9,12]. (See "Cardiovascular disease risk assessment for primary prevention: Risk calculators", section on 'QRISK3 (2018)'.)

●Identify patients at high risk – Some groups of younger individuals are at high, long-term risk of ASCVD events and benefit from earlier intervention strategies. These include:

•Familial hypercholesterolemia

•Patients with juvenile onset of type 1 diabetes mellitus (DM) or early onset of type 2 DM

ASCVD risk assessment and risk modification in these patients are discussed separately. (See 'Patients in whom risk calculators may underestimate risk' below and "Familial hypercholesterolemia in adults: Overview" and "Overview of general medical care in nonpregnant adults with diabetes mellitus", section on 'Reducing the risk of macrovascular disease'.)

Patients ages 30 to 79 years

Estimate 10-year ASCVD risk using a calculator — All individuals ages 30 to 79 years of age should undergo quantitative ASCVD risk estimation using a validated risk calculator (algorithm 1). Further risk stratification depends on ASCVD risk estimates, as discussed below. (See 'Additional risk stratification and management' below.)

Lowering the age threshold for starting ASCVD risk calculations from age 40 to 30 years is based on data derived primarily from individuals in the United States. Professional guidelines both within and outside the United States suggest different age thresholds at which to begin quantitative risk calculations [9,12-15].

Quantitative 10-year ASCVD risk estimation enables clinicians to tailor preventive strategies to the patient's absolute risk of disease, which ideally maximizes benefits and minimizes harms of overtreatment [5]. Quantitative risk estimates can facilitate individualized risk discussions and recommendations about risk modification and may help patients change their behavior. As an example, showing patients who smoke how quitting smoking reduces their 10-year risk of ASCVD may help motivate them to stop smoking. For individuals at intermediate and high ASCVD risk, quantitative risk estimates can help to tailor the intensity of pharmacotherapy for treating hypertension and elevated low-density lipoprotein cholesterol and inform decisions about the use of aspirin.

Data supporting the use of these risk estimates to guide specific primary prevention strategies are most robust for individuals between ages 40 and 75 years.

Choosing a risk calculator — We encourage clinicians to become familiar with and use an ASCVD risk calculator that has been validated for their locale and patient population. Several ASCVD risk calculators are in widespread use that capture population-specific risk profiles. In selecting a risk calculator for an individual patient, we consider the generalizability of the calculator's data to the patient, the inclusion of specific risk factors, and the outcomes being predicted. Risk models that predict clinical events (ie, death, myocardial infarction, stroke) are preferable to those that include other endpoints (ie, revascularization). No single risk model will be appropriate for all patients [16,17].

Several calculators currently in use in the United States and the United Kingdom are listed below. A comprehensive discussion of cardiovascular risk calculators appears elsewhere. (See "Cardiovascular disease risk assessment for primary prevention: Risk calculators".)

●United States – In the United States, we use the 2023 AHA Predicting Risk of cardiovascular disease EVENTs (PREVENT) calculator or the 2018 ASCVD Risk Estimator Plus.

•The 2023 AHA PREVENT calculator estimates 10-year risks of total cardiovascular disease and its subtypes, heart failure, and ASCVD for individuals aged 30 to 79 and 30-year risks in adults aged 30 to 59 [7,18]. The PREVENT calculator is available online. It was developed, in part, because the 2013 ACC/AHA pooled cohort equations (PCEs) can overestimate ASCVD risk in contemporary populations [16,19-24]. The PREVENT calculator was derived and validated with more modern clinical data obtained between 1992 and 2017 from cohort studies and electronic health records that included more than 6.6 million patients [18].

The PREVENT calculator includes the traditional risk factors (age, sex, total and high-density lipoprotein cholesterol, systolic pressure level, DM, current smoking, and blood pressure medication) as well as additional factors (estimated glomerular filtration rate, body mass index, and lipid-lowering medication) and optional factors (urinary albumin-creatinine ratio, glycated hemoglobin, and zip code for estimating the social deprivation index). The online calculator provides both 10-year and 30-year risks for cardiovascular disease and heart failure.

The PREVENT algorithm requires that the users enter information for more factors than in the past to estimate risk, and some of the optional factors, such as zip code, are only applicable to United States residents. Familiarity will grow with greater use by clinicians and as smart phone applications become available.

ASCVD risk estimates obtained from the PREVENT calculator will likely differ from those from the 2013 ACC/AHA PCE calculator and may result in different treatment recommendations for individual patients. At the population level, the PREVENT calculator lowers the number of individuals who qualify for primary prevention measures, including statin therapy. In a nationally representative study using cross-sectional data from the 2017 to 2020 National Health and Nutrition Examination Survey, use of the PREVENT calculator in a sample of United States adults aged 40 to 75 years resulted in a lower mean estimated 10-year ASCVD risk, compared with use of the 2013 PCEs (4.3 percent [95% CI 4.1-4.5] versus 8.0 percent [95% CI 7.6-8.4]) [25]. Lower 10-year risk estimates occurred across all age, sex, and racial subgroups and were largest for Black adults (5 versus 11 percent) and individuals aged 70 to 75 years (10 versus 23 percent). The PREVENT calculator likely provides a potentially important downward correction to the 2013 PCEs ASCVD risk estimates for United States populations [26]. Large, population-based prospective cohorts will offer additional validation of these estimates.

•The 2018 ASCVD Risk Estimator Plus incorporates data from the 2013 ACC/AHA PCEs (calculator 1) and the 2016 Million Hearts Longitudinal ASCVD Risk assessment tool. It updates risk predictions based on initiation of and response to therapies (aspirin, statins, and antihypertensive therapy) and smoking cessation [4,6,19]. This model estimates 10-year risk of ASCVD for individuals aged 40 to 79 and estimates 30-year, or lifetime, risk for individuals aged 20 to 59. It uses data primarily from cohorts of non-Hispanic White and Black Americans.

The PREVENT calculator and the ASCVD Risk Estimator Plus may underestimate risk in certain groups of individuals. (See 'Risk-enhancing factors' above and 'Patients in whom risk calculators may underestimate risk' below.)

●United Kingdom – The 2023 National Institute for Health and Care Excellence guidelines recommend use of the QRISK3 calculator [13,27] to calculate 10-year and lifetime ASCVD risk estimates for adults aged 25 to 84 years at increased risk of ASCVD [9]. (See "Cardiovascular disease risk assessment for primary prevention: Risk calculators".)

●Western Europe other than United Kingdom – The Systematic COronary Risk Evaluation 2 (SCORE2) risk model was published in 2021 [14]. The 2021 European Society of Cardiology guidelines on cardiovascular disease prevention recommended use of the SCORE2 model for individuals in Europe aged 40 to 69 years old and SCORE2-Older Persons (SCORE2-OP) for individuals 70 years and older [12].

●China – China-PAR (Prediction for ASCVD Risk in China) calculator [28].

●Other regions – The World Health Organization cardiovascular disease updated risk charts were published in 2019. These are available as color-coded charts for 21 worldwide regions for individuals aged 40 to 74 years old [15,29].

When to estimate 30-year ("lifetime") risk — We calculate 30-year (or lifetime) ASCVD risk in patients ages 30 to 59 whose 10-year risk estimates are low (<5 percent) or borderline (5 to 7.5 percent) [19]. Quantifying 30-year ASCVD risk in these individuals can further refine risk stratification because many younger individuals with a low calculated 10-year ASCVD risk will still have a high lifetime risk [7]. Individuals with low 10-year but high 30-year ASCVD risk (ie, >39 percent) demonstrate higher rates of subclinical atherosclerosis and slightly increased rates of incident ASCVD, compared with those with low 10- and 30-year risk estimates [30,31]. However, despite the appeal of using 30-year ASCVD risk estimates, a paucity of data exists regarding the long-term benefits and harms of statins and other pharmacotherapy on clinical outcomes in the setting of primary prevention.

Calculators that estimate 30-year risk in younger individuals include the PREVENT calculator, ASCVD Risk Estimator Plus, and QRISK3 risk calculator. (See 'Choosing a risk calculator' above.)

Support for the role of 30-year risk estimates in guiding primary ASCVD prevention comes from a cohort analysis of almost 28,000 middle-aged (mean age 55 years) females without cardiovascular disease [32]. In this cohort, baseline levels of high-sensitivity C-reactive protein, low-density lipoprotein cholesterol, and lipoprotein(a) were each independently associated with increased risk of a first major adverse cardiovascular event (a composite of myocardial infarction, coronary revascularization, stroke, or death from cardiovascular causes) at 30-year follow-up. These three biomarkers were similarly associated with coronary heart disease and stroke event risks. The risks of elevated biomarkers were additive; elevated levels of all three biomarkers conferred the highest cardiovascular risk. However, the analysis did not compare the accuracy of biomarker-based 30-year ASCVD risk stratification with 30-year risk estimates derived by ASCVD calculators.

Patients over 79 years of age — For patients older than 79 years of age, we individualize ASCVD risk assessment, discuss the risks and benefits of primary preventive therapies in the context of the individual's overall health, and pursue shared decision-making regarding further risk stratification and intervention.

For individuals without significant comorbidities or limited life expectancy who want to prioritize ASCVD risk reduction, quantitative 10-year ASCVD risk assessments using a calculator may augment these discussions by providing more precise risk estimates. Given that age is the primary driver of risk calculations, most of these patients will have at least an intermediate ASCVD risk, even if they have few to no other cardiovascular risk factors. Risk calculators may potentially overestimate ASCVD risk in such individuals. (See "Coronary artery calcium (CAC) scoring: Overview and clinical utilization", section on 'Older adults'.)

Limited data exist regarding the utility of formal ASCVD risk estimates (using a calculator) or primary prevention strategies in older individuals, particularly for those ages 80 and older [5]. Although the absolute risks of ASCVD events are higher in older adults, the relative risk reduction from primary prevention with statin treatment is lower in this group, and some adverse effects of pharmacotherapies (eg, bleeding with aspirin use) are also increased.

Most available risk calculators have an upper age limit for ASCVD risk estimation. The United States' PREVENT and ASCVD Risk Estimator Plus calculate risk for adults up to age 79, and the United Kingdom's QRISK3 provides calculations for adults up to age 84 [9]. Only the European SCORE2-OP model was developed specifically for quantifying risk in older populations (≥70 years) [12]. If a patient's age exceeds the upper age limit of the risk calculator that is most applicable (based on geographic location) and the patient and clinician decide to pursue quantitative risk estimates, the clinician can enter the oldest age that the calculator accepts to approximate that patient's 10-year ASCVD risk.

Decisions regarding discontinuing periodic risk assessment should be made collaboratively with patients based on their overall functional and health status, life expectancy, risk of side effects, and values and preferences for risk factor modification.

PATIENTS IN WHOM RISK CALCULATORS MAY UNDERESTIMATE RISK

●Patients with LDL cholesterol ≥190 mg/dL (≥4.9 mmol/L) – Individuals with severely elevated low-density lipoprotein (LDL) cholesterol (≥190 mg/dL) are at very high risk of future cardiovascular events. These patients typically need evaluation for familial hypercholesterolemia and intensive management with recommended lifestyle modifications and lipid-lowering medications. Their management is discussed separately. (See "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease", section on 'LDL-C greater than or equal to 190 mg/dL' and "Familial hypercholesterolemia in adults: Overview" and "Aspirin in the primary prevention of cardiovascular disease and cancer", section on 'Level of risk'.)

●Patients with familial hypercholesterolemia – ASCVD risk calculators do not apply to individuals with familial hypercholesterolemia (homozygous or heterozygous), as these individuals are at very high risk for ASCVD [6,7,33]. These individuals generally require aggressive lipid-lowering therapy and other primary prevention strategies to reduce their high risk of ASCVD. Assessment and management of ASCVD risk in patients with familial hypercholesterolemia is discussed separately. (See "Familial hypercholesterolemia in adults: Overview" and "Familial hypercholesterolemia in adults: Treatment".)

●Patients with type 1 DM – Most risk calculators underestimate ASCVD risk in those with type 1 diabetes, and clear evidence for quantitative risk estimation in this population is lacking. Even young patients (eg, age <40 years) are at high risk of ASCVD events, particularly if their initial diagnosis occurred at an early age. These individuals typically require multifactorial risk factor reduction (eg, control of blood pressure, hyperglycemia, and lipids) to minimize their likelihood of future cardiovascular events and mortality. Risk factor discussions with these patients should also mention the risk of microvascular disease (eg, retinopathy, kidney disease with albuminuria). (See "Overview of general medical care in nonpregnant adults with diabetes mellitus", section on 'Reducing the risk of macrovascular disease'.)

●Patients with type 2 DM – Formal ASCVD risk calculations in individuals with type 2 diabetes mellitus (DM) should be performed and interpreted with care. Some risk calculators underestimate ASCVD risk in these patients because they do not include diabetes or related markers of ASCVD risk, such as kidney function, albuminuria, and glycemic control (see 'Risk-enhancing factors' above). Selected risk calculators that include some or all of these parameters include the 2023 American Heart Association Predicting Risk of cardiovascular disease EVENTs (PREVENT) calculator and the 2018 United Kingdom QRISK3 risk calculator.

Similar to patients with type 1 DM, patients with type 2 DM are at high risk of ASCVD events and need intensive risk factor management and counseling about both macrovascular and microvascular risk. (See "Overview of general medical care in nonpregnant adults with diabetes mellitus", section on 'Reducing the risk of macrovascular disease'.)

●Patients with risk-enhancing factors – Risk calculators may underestimate ASCVD risk in individuals with one or more risk-enhancing factors (table 1), particularly when the factors are not included in the chosen risk calculator. (See 'Risk-enhancing factors' above.)

ADDITIONAL RISK STRATIFICATION AND MANAGEMENT — 

Although we typically encourage specific primary prevention strategies for patients with a given level of 10-year ASCVD risk, we use these thresholds first and foremost to initiate discussions about ASCVD risk modification and guide shared decision-making [34]. This process should inform the patient about the certainty of evidence for specific primary prevention strategies in those at a given age and level of ASCVD risk [35]. The discussion should also incorporate the individual's values and priorities and recognize that patients have different thresholds for taking medications and engaging in ongoing primary prevention activities (algorithm 1).

Low risk (<5 percent) — We encourage all patients in this group to adapt or maintain healthy lifestyles (eg, regular exercise, healthy diet). (See "Overview of primary prevention of cardiovascular disease in adults", section on 'Promoting a healthy lifestyle'.)

For younger individuals (ages 30 to 59 years) in this group, we also calculate their 30-year ASCVD risk and use this information to help patients prioritize lifestyle changes and ASCVD risk reduction. (See 'When to estimate 30-year ("lifetime") risk' above.)

We typically reassess ASCVD risk within four to six years in this group of patients, with shorter intervals for persons whose risk factor status changes (eg, new onset hypertension).

Borderline risk (5 to <7.5 percent) — The management of individuals with borderline 10-year ASCVD risk starts with discussion of lifestyle changes. We examine potential risk-enhancing factors (table 1) and for individuals ages 59 or younger, 30-year ASCVD risk estimates to inform decisions about statin therapy and other primary prevention strategies (see 'When to estimate 30-year ("lifetime") risk' above). As an example, for younger patients with a high 30-year ASCVD risk (eg, >39 percent) and one or more risk-enhancing factors, we discuss the use of statin therapy. (See "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease", section on 'Intermediate (5 to 7.4 percent) 10-year CVD risk'.)

Additional risk stratification with coronary artery calcium (CAC) may help to guide decisions about statin therapy and other primary prevention interventions in higher-risk individuals in this group, especially when uncertainty persists after initial ASCVD risk assessment or for patients who are uncertain about the benefit of starting statin therapy. The use of CAC scoring in individuals with borderline 10-year ASCVD risk scores is discussed separately. (See "Coronary artery calcium (CAC) scoring: Overview and clinical utilization", section on 'Patients we may screen'.)

The ideal time interval for reassessing risk in this group of individuals is uncertain; however, yearly reassessment is reasonable to optimize risk factor reduction. Those who start medications will require sooner follow-up for treatment monitoring. (See "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease", section on 'Subsequent management'.)

Intermediate risk (7.5 to <20 percent) — Many individuals at intermediate 10-year ASCVD risk benefit from statin therapy and other primary prevention measures, particularly if they have risk-enhancing factors or are at the higher end of this range. (See "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease", section on 'High (7.5 to 20 percent) and very high (greater than or equal to 20 percent) 10-year CVD risk'.)

For patients without risk enhancers whose 10-year ASCVD risk is at the lower end of this range, we discuss the relative risks and benefits of statin therapy and other primary prevention measures. For patients who prefer to avoid lipid-lowering medications or for whom the decision remains unclear, we discuss additional risk stratification with CAC scoring. (See "Coronary artery calcium (CAC) scoring: Overview and clinical utilization", section on 'Patient selection for CAC screening'.)

Additional risk refinement with CAC scoring could potentially reclassify ASCVD risk upward (eg, CAC scores ≥100) or downward (eg, CAC scores 0 or ≤10) and alter decisions regarding primary prevention therapies [5,36,37]. CAC testing may be particularly useful in older individuals for whom the primary driver of the calculated risk score is age, rather than traditional risk factors. The selection of patients for CAC screening, CAC score interpretation, and further management are discussed separately. (See "Coronary artery calcium (CAC) scoring: Overview and clinical utilization".)

The ideal time interval for reassessing risk in this group of individuals is uncertain; however, yearly measurement and discussion of risk reduction strategies are reasonable to optimize risk factor reduction. Those who start medications will require sooner follow-up for treatment monitoring and adjustment. (See "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease", section on 'Subsequent management'.)

High risk (20 percent and higher) — Individuals at high 10-year ASCVD risk do not need additional risk stratification. They should receive primary prevention interventions that include intensive lifestyle changes, pharmacotherapy (eg, statin and medication to treat hypertension, if present), and ongoing monitoring and follow-up. (See "Low-density lipoprotein cholesterol-lowering therapy in the primary prevention of cardiovascular disease", section on 'High (7.5 to 20 percent) and very high (greater than or equal to 20 percent) 10-year CVD risk'.)

SOCIETY GUIDELINE LINKS — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Assessment of cardiovascular risk".)

SUMMARY AND RECOMMENDATIONS

●ASCVD risk assessment – A comprehensive approach to atherosclerotic cardiovascular disease (ASCVD) risk assessment consists of identifying risk factors and, for most individuals, ASCVD risk estimation using a risk calculator (algorithm 1). (See 'Terminology' above.)

ASCVD risk assessment and discussions should begin at 20 years of age or at first encounter with the health care system beyond 20 years of age.

•Identification of risk factors – For all individuals, the first step in assessing ASCVD risk involves determining whether one or more traditional ASCVD risk factors (hypertension, cigarette smoking, diabetes mellitus [DM], or obesity) and/or risk-enhancing factors are present. This includes obtaining a baseline lipid profile if this has not been done previously. (See 'Identify risk factors' above and "Overview of primary prevention of cardiovascular disease in adults".)

Risk-enhancing factors may significantly alter risk for individual patients and can inform the clinician-patient discussion of ASCVD risk and primary prevention therapies (table 1). (See 'Risk-enhancing factors' above.)

•Patients ages 20 to 29 years – For patients between ages 20 and 29 years, we assess the lifetime risk of ASCVD and identify individuals at high ASCVD risk. We typically do not perform quantitative ASCVD risk estimation using a risk calculator in this group of patients. (See 'Patients ages 20 to 29 years' above.)

•Patients ages 30 to 79 years – All individuals ages 30 to 79 years of age should undergo quantitative ASCVD risk estimation using a validated risk calculator. (See 'Estimate 10-year ASCVD risk using a calculator' above.)

-Choosing a risk calculator – Clinicians should become familiar with and use an ASCVD risk calculator that has been validated for their locale and patient population. Commonly used calculators in the United States include the 2023 American Heart Association Predicting Risk of cardiovascular disease EVENTs (PREVENT) calculator or the 2018 ASCVD Risk Estimator Plus. (See 'Choosing a risk calculator' above and "Cardiovascular disease risk assessment for primary prevention: Risk calculators".)

-Estimating 30-year ("lifetime") risk – We calculate 30-year (or lifetime) ASCVD risk in patients ages 30 to 59 whose 10-year risk estimates are low (<5 percent) or borderline (5 to 7.5 percent) because these results may further refine risk stratification and help to guide primary prevention strategies. (See 'When to estimate 30-year ("lifetime") risk' above.)

•Patients over 79 years of age – For patients ages 80 and older, we individualize ASCVD risk assessment. This entails discussing the risks and benefits of primary preventive therapies in the context of the individual's overall health and pursuing shared decision-making regarding further risk stratification and intervention. (See 'Patients over 79 years of age' above.)

•Patients at very high ASCVD risk – ASCVD risk calculators are not applicable for patients with low-density lipoprotein cholesterol ≥190 mg/dL (≥4.9 mmol/L) and/or familial hypercholesterolemia; these patients are at very high risk for ASCVD. ASCVD risk is also very high for adults with type 1 DM. Such individuals require intensive risk factor modification. (See 'Patients in whom risk calculators may underestimate risk' above.)

●Additional evaluation and management – Results from 10- and 30-year ASCVD calculations provide a starting point for risk-benefit discussions and recommendations for primary prevention therapies (algorithm 1). The discussion should also incorporate the individual's values and priorities and recognize that patients have different thresholds for taking medications and engaging in ongoing primary prevention activities. Additional factors that can inform risk discussions include the presence of risk-enhancing factors and for select patients, coronary artery calcium scoring. (See 'Additional risk stratification and management' above.)