What is cardiovascular risk?

What is Cardiovascular Risk?

Cardiovascular risk is the probability that an individual will develop or die from an atherosclerotic cardiovascular event (such as myocardial infarction, stroke, or peripheral arterial disease) over a defined time period, typically expressed as a percentage over 10 years. 1

Core Concept: Total Risk Assessment

Cardiovascular risk assessment moves beyond evaluating single risk factors to calculate total or global risk by combining multiple factors simultaneously. 1 This approach recognizes that:

• Multiple modest elevations in several risk factors can produce unexpectedly high total risk, even when no single factor appears severely abnormal 1
• The combined effect of risk factors is multiplicative rather than simply additive 1
• An individual's absolute risk depends not only on their ranking within a population but on the baseline risk of that entire population 1

Major Risk Factors That Determine Cardiovascular Risk

The primary determinants used in risk calculation include: 1

• Age - the single strongest independent predictor, reflecting accumulated atherosclerotic burden over decades 2
• Sex - men carry higher risk at younger ages, though this advantage diminishes in women with multiple risk factors 1
• Blood pressure - both systolic and diastolic elevations contribute independently 1
• Lipid levels - total cholesterol, LDL cholesterol, and HDL cholesterol (low HDL increases risk) 1
• Smoking status - current tobacco use 1
• Diabetes mellitus - particularly type 2 diabetes 1

Risk Categories and Clinical Thresholds

High-Risk Individuals 1

• Patients with established atherosclerotic disease (coronary disease, stroke, peripheral arterial disease) - these individuals already have manifest disease and face high recurrence risk
• 10-year CVD death risk ≥5% (European guidelines) or 10-year ASCVD risk ≥7.5-10% (U.S. guidelines) 1
• Type 2 diabetes with additional risk factors or target organ damage 1
• Severe single risk factor elevations with end-organ damage 1

Intermediate-Risk Individuals 1

• 10-year CVD event risk between 7.5-20% depending on the risk calculator used
• Often have multiple modestly elevated risk factors 1

Low-Risk Individuals 1

• 10-year CVD event risk <7.5% (U.S. thresholds) or <5% (European thresholds)
• The vast majority of adults aged 40-49 years fall into this category (93% of women, 81% of men) 1

Risk Assessment Tools

Primary Calculators

For U.S. populations: The Pooled Cohort Equations estimate 10-year risk of myocardial infarction, coronary death, or stroke using age, sex, race, total cholesterol, HDL cholesterol, systolic blood pressure, antihypertensive treatment, diabetes, and smoking. 1, 3

For European populations: The SCORE system estimates 10-year CVD mortality risk using age, sex, total cholesterol, HDL cholesterol, smoking, and systolic blood pressure. 1, 3

Important Limitations

• Risk calculators derived from one population may not accurately predict risk in another population with different baseline characteristics 1
• Young individuals may have low short-term risk but high projected lifetime risk - European guidelines recommend projecting risk to age 60 for younger adults 1
• Traditional calculators may underestimate risk in patients with familial dyslipidemias, strong family history of premature CVD, or certain ethnic backgrounds 1

The Continuum of Risk

Cardiovascular prevention exists on a continuum from low to high risk rather than in discrete categories. 1 This concept challenges traditional distinctions between primary, secondary, and tertiary prevention:

• Patients with established CVD are at highest risk because they have already declared their disease 1
• Asymptomatic individuals at high total risk often have similar or identical atherosclerotic burden (though subclinical) as those with symptomatic disease 1
• Both groups require similarly aggressive risk factor management 1

Additional Risk Modifiers

Underlying Risk Factors 1

These factors influence risk partly through major risk factors and partly through independent mechanisms:

• Overweight/obesity
• Physical inactivity
• Atherogenic diet
• Socioeconomic and psychosocial stress
• Family history of premature CVD
• Genetic and racial factors

Emerging Risk Factors 1

These show correlation with CVD but are not routinely included in standard risk equations:

• Triglycerides, apolipoproteins, lipoprotein(a)
• Insulin resistance
• Prothrombotic markers (fibrinogen)
• Proinflammatory markers (C-reactive protein)

Risk-Enhancing Factors 3

For borderline or intermediate-risk patients, consider:

• Family history of premature ASCVD
• Metabolic syndrome
• Chronic kidney disease
• Persistently elevated LDL-C ≥160 mg/dL
• Coronary artery calcium score (can refine risk assessment in intermediate-risk patients) 3

Clinical Application

The fundamental purpose of cardiovascular risk assessment is to identify who will benefit most from preventive interventions - those at highest absolute risk gain the most from treatment, even if their relative risk reduction is similar to lower-risk individuals. 1

Risk assessment should guide intensity of:

• Lifestyle modification counseling 1
• Blood pressure targets (more aggressive for high-risk: <130/80 mmHg) 1
• Lipid targets (more aggressive for high-risk: LDL <2.5 mmol/L or <100 mg/dL) 1
• Consideration of cardioprotective medications (antiplatelet agents, statins, ACE inhibitors) 1

Common Pitfall

Do not focus on single risk factors in isolation. A patient with "borderline" cholesterol, "borderline" blood pressure, and smoking may have substantially higher total risk than someone with a single severely elevated risk factor. 1 Always calculate total risk before making treatment decisions.