Atherosclerotic cardiovascular disease (ASCVD) poses a significant global health threat, encompassing coronary artery disease (CAD), cerebrovascular disease (CeVD), and peripheral artery disease (PAD). Understanding the modifiable risk factors and implementing preventive measures are crucial in mitigating ASCVD's impact on morbidity and mortality. 

Atherosclerotic cardiovascular disease (ASCVD), composed primarily of coronary artery disease (CAD), cerebrovascular disease (CeVD) and peripheral artery disease (PAD) is a major component of cardiovascular disease (CVD).² CVD is a major cause of disability and premature death throughout the world.³ Indeed, more people die each year from cardiovascular diseases (CVDs) than from any other cause.⁴ Furthermore, over three quarters of heart disease and stroke-related deaths occur in low and middle-income countries.⁴ 

The development of CVD is influenced by several modifiable risk factors including:⁴ Continued exposure to these risk factors leads to progression of atherosclerosis, resulting in clinical manifestations of ASCVD such as angina pectoris, myocardial infarction, heart failure, stroke, and peripheral artery disease. However, risk factor modification can reduce clinical events and premature death both in people with established ASCVD as well as in those who are at high risk of ASCVD due to one or more risk factors.³ Therefore, attempts to prevent or reduce modifiable risk factors can reduce the burden of ASCVD, making it an attractive target for preventative measures.² Prevention has, in fact, played a pivotal role in the reduction in ASCVD morbidity and mortality seen over the last three decades.² Current approaches to prevention of ASCVD involve two categories of prevention for two categories of patients³: 

• Primary Prevention
• People with risk factors who have not yet developed clinically manifest CVD
• Secondary Prevention
• People with established ASCVD viz.: CAD, CeVD or PAD.

Additionally, a critical step in the current approach to prevention of ASCVD is risk assessment which involves estimating a patient’s 10-year risk of an ASCVD event.² Knowledge of the 10-year risk for ASCVD events enables clinicians to target those who will benefit most from risk-reducing therapy.2 This risk assessment is carried out using ASCVD Risk Estimator tools of which there are multiple available including: 

• Framingham Risk Score, which predicts 10-year risk of MI or CAD-related death.² 
• 2013 ACC / AHA prevention guidelines (pooled cohort) ASCVD Risk Estimator which predicts the 10-year risk and lifetime risk of an ASCVD event (coronary death, MI, stroke). This pooled cohort risk assessment tool incorporates the same traditional elements of the Framingham Risk Score but includes a mechanism for predicting lifetime risk, which, when elevated, warrants early aggressive lifestyle and risk factor modification, even when the 10-year risk may not.²

RISK ASSESSMENT

The first step in prevention is to assess a patient’s 10-year risk of having an ASCVD event using a validated ASCVD Risk Estimator Tool. This will facilitate the identification of those who will benefit most from risk-reducing therapy. Risk Assessment for Primary Prevention Risk assessment in primary prevention involves those patients with risk factors who have not yet developed clinically manifest CVD. The American College of Cardiology / American Heart Association (ACC / AHA) risk assessment guidelines recommend that⁵: 

• Adults aged 20 to 79 years old should have risk factors assessed at least every 4 to 6 years for primary prevention.
• Adults aged 40 to 79 years should have a 10-year risk estimation done using the pooled cohort risk assessment tool.
• Younger adults aged 20 to 59 years at low 10-year risk should be considered for 30-year or lifetime ASCVD risk assessment.

RISK ASSESSMENT 

These guidelines make further recommendations regarding situations where quantitative risk decisions remain uncertain even after risk estimation. In such situations, it is recommended that additional factors be considered, which includes coronary artery calcium (CAC) scoring. CAC scoring as measured by non-contrast cardiac computed tomography is the most predictive test of CVD risk in those for whom the decision to start a statin is still uncertain.² 

Risk Assessment for Secondary Prevention 

Risk assessment in secondary prevention involves those with established ASCVD or very high levels of individual risk factors but is much more straight-forward. In this group of patients, risk assessment is not necessary for making treatment decisions because they are considered to already be at a high risk of ASCVD. They are all recommended for aggressive lifestyle interventions, and furthermore the benefits of pharmacotherapy (i.e.: aspirin, statin) are well established in this group of patients.^1,2 

Clinician Guide to the ABCs of Primary and Secondary Prevention of Atherosclerotic Cardiovascular Disease¹ 

The ABCDEs of cardiovascular disease prevention was first proposed in 2001 as a simple template to address the key components of risk factor modification. The “Clinician Guide to the ABCs of Primary and Secondary Prevention of Atherosclerotic Cardiovascular Disease” is an update of these prior papers.^{1, 6, 7} It is a template for clinicians to address the key components of risk factor modification in the primary and secondary prevention of CVD. It is a structured approach intended to identify patients at a high risk for CVD and to provide appropriate lifestyle and pharmacological interventions in a time constrained busy clinical practice. The recommendations are based on updated guidelines. The initial step in prevention is the assessment and estimation of an individual’s 10-year risk of having an ASCVD event in order to identify high risk patients. This is followed by appropriately addressing the key components of risk factor modification in the ABCDEF flow format as summarised next. 

ASSESS RISK: 

Primary Prevention 

• Assess all adults for risk factors at least every 4 – 5 years, starting from the age of 20 years.
• For asymptomatic adults aged 40 – 79, not already on a statin:
  • Apply a CVD Risk Estimator (pooled cohort equation or similar alternative such as Framingham Risk Score), to estimate the
    10-year risk of having an ASCVD event. 
• Some patient groups are often at a higher risk than predicted, including:
  • Those with HIV or chronic inflammatory disorders.
  • Women with a history of preeclampsia, pregnancy-induced hypertension, polycystic ovarian syndrome and / or gestational diabetes.
• When risk-treatment decisions are still uncertain after risk assessment, consider the use of coronary artery calcium (CAC).
• For Adults aged 20 – 59 years with a low 10-year risk, estimate the 30 year or lifetime risk for ASCVD.

Secondary Prevention 

• Aggressive comprehensive risk factor modification if known or established ASCVD:
  • Coronary artery disease
  • Cerebrovascular disease
  • Peripheral artery disease. 

 ANTIPLATELET THERAPY 

• Consider aspirin 81 mg / day if:
  • 10-year ASCVD risk estimate is ≥10 %, and
  • Potential benefit outweighs bleeding risk after clinician-patient risk discussion. 

Secondary Prevention 

• Aspirin 81 – 162 mg/day indefinitely.
• If PCI was performed after ACS event Aspirin plus clopidogrel, prasugrel or ticagrelor (ie P2Y12 Inhibitor) as follows:
  • If bare metal stent, P2Y12 inhibitors should be taken for ≥1 month
  • If drug-eluting stent, P2Y12 inhibitors should be taken for ≥1 year
  • If on dual antiplatelet therapy (DAPT), use aspirin 81 mg/day
• If no PCI was performed after an ACS event, use either clopidogrel or ticagrelor
• Do not use prasugrel if history of stroke or TIA. Caution in those over 70 years of age
• Aspirin 81 mg to 325 mg/day or clopidogrel for all patients following a non-cardioembolic ischaemic stroke.

ATRIAL FIBRILLATION 

Primary Prevention 

• Control and prevention of risk factors for:
  • Hypertension
  • Obesity
  • Diabetes mellitus 

Secondary Prevention 

• Warfarin or direct oral anticoagulant (DOAC) for CHA2DS2-VASC ≥ 2*8
• Aspirin if CHA2DS2-VASc ≤
• Consider rhythm control

BLOOD PRESSURE 

Primary Prevention 

• Lifestyle interventions:
  • Exercise, diet, weight management, smoking cessation
  • Limit alcohol consumption:
    • Male ≤ 2 drinks per day
    • Female ≤ 1 drink per day 

Secondary Prevention 

• BP goal < 130/80 mmHg
• Pharmacotherapy according to guidelines:
  • May start with lifestyle changes depending on:
    • Stage of hypertension, and
    • ASCVD risk estimate:
      • If ASCVD risk estimate < 10 %, can start with lifestyle changes alone. 

CHOLESTEROL 

• Lifestyle interventions:
  • Exercise, diet, weight management, smoking cessation
  • Limit alcohol consumption:
    • Male ≤ 2 drinks per day
    • Female ≤ 1 drink per day
• Patients aged 40 – 75 years with diabetes mellitus and LDL-C: 70 - 189 mg/dL (1.8 - 4.8 mmol/L), but without clinical ASCVD:
  • If 10-year ASCVD risk ≥ 7,5 %: high intensity statin therapy
  • If 10-year ASCVD risk < 7,5 %: moderate intensity statin therapy. 

Primary Prevention 

• Patients with primary elevations of LDL-C: ≥ 190 mg/dL (4.9 mmol/L):
  • High or moderate intensity statin therapy
• Consider moderate to high intensity statin therapy after risk discussion with patient if:
  • ASCVD risk estimate is ≥ 7,5 %
  • If still uncertain after risk assessment and discussion, consider use of CAC scan if risk estimate is between 5 – 20 % 

Factors supporting statin use if risk decision is uncertain: 

• LDL-C ≥ 160 mg/dL (4.1 mmol/L) 
• Family history of premature ASCVD 
• High lifetime ASCVD risk
• Presence of CAC – especially if > 75th percentile for age / gender or absolute score ≥ 100. 

Secondary Prevention 

• Lifestyle interventions
• Moderate to high intensity statin therapy for patients with:
  • Clinical ASCVD (acute coronary syndromes, MI, stable or unstable angina, coronary or any other arterial revascularization, stroke, TIA, or PAD).
  • Unless NYHA Class II – IV heart failure or receiving haemodialysis.
• If after trial of highest tolerated dose of high-intensity statin:
  • LDL-C ≥ 70 mg/dL (1.8 mmol/L), non-HDL-C ≥100 mg/dL (2.5 mmol/L) and high risk for another ASCVD event, thenConsider Ezetimibe and / or PCSK9 Inhibitors.
• If triglycerides > 500 mg/dL then consider fibrates and / or high dose omega 3.

CIGARETTE / TOBACCO CESSATION 

Primary and Secondary Prevention 

• Education 
• Assessment of triggers and counselling 
• Pharmacotherapy (nicotine patches, varenicline, bupropion) 

DIET / WEIGHT MANAGEMENT 

Primary and Secondary Prevention 

If overweight, aim for loss of 3 – 10 % of body weight by caloric restriction and  increased physical activity as part of a comprehensive lifestyle programme. 

• Goal BMI: 18,5 – 24,9 kg/m2 
• Goal waist circumference: 
• Male : < 94 cm 
• Female : < 80 cm. 

DIABETES: PREVENTION AND TREATMENT

Lifestyle Interventions:

• Exercise, diet, weight management, smoking cessation
  • Limit alcohol consumption
    • Male ≤ 2 drinks per day
    • Female ≤ 1 drink per day
• Treat elevated cholesterol as outlined above

Secondary Prevention 

• Lifestyle interventions
• Nutritionist
• Anti-hyperglycaemics as per guidelines
• Treat hypertension if present
• Treat elevated cholesterol.

EXERCISE 

Primary and Secondary Prevention 

• Controlled cardiac rehabilitation for patients who have had an ASCVD event or heart failure with reduced ejection fraction (LVEF ≤ 35%)
• Moderate to vigorous aerobic exercise for a total of at least 150 minutes per week:
  • eg: 30 minutes, five sessions per week, or
  • Another reasonable target based on baseline activity. 

HEART FAILURE 

Primary Prevention 

• Treat heart failure risk factors 
• Lifestyle Interventions:
  • Exercise, diet, weight management, smoking cessation
  • Limit alcohol consumption:
    • Male ≤ 2 drinks per day
    • Female ≤ 1 drink per day
• Hypertension, diabetes mellitus, dyslipidaemia. 

Secondary Prevention 

Lifestyle interventions: 

• Control blood pressure, blood sugar, blood cholesterol 
• Reinforce adherence to medications 
• Cardiac rehabilitatione. 

CONCLUSION 

Guidelines summarise and evaluate available evidence with the aim of assisting healthcare professionals in appraising and selecting the best management strategies for their patients. These recommendations should facilitate decision making in daily practice. However, the final decisions concerning patients must be made by the responsible healthcare professional in consultation with the patient.  

Healthy lifestyle choices and the treatment and control of concomitant CVD risk factors (eg: blood pressure, lipids, blood sugar) remain essential components of both primary and secondary prevention of CVD. 

Furthermore, risk factor modification can reduce clinical events and premature death in people who are at high cardiovascular risk due to one or more risk factors (primary prevention) as well as in people with established CVD (secondary prevention). In view of this, the ABCDEF prevention strategy has been proposed for use by healthcare professionals in the management of their patients in an attempt to decrease the overall CVD burden. In addition, this format can be used for easy communication of recommendations to other members of the healthcare team that might be involved in patient care and the patients themselves.  

References available on request.