Cardiovascular Risk Classification

Conducting a comprehensive risk assessment

• In adults without known CVD, a comprehensive assessment of cardiovascular risk includes
• consideration of the following:
  • Modifiable risk factors
    • Smoking status
    • Blood pressure
    • Serum lipids
    • Waist circumference and Body Mass Index (BMI)
    • Nutrition
    • Physical activity level
    • Alcohol intake.
  • Non-modifiable risk factors
    • Age and sex
    • Family history of premature CVD
    • Social history including cultural identity, ethnicity and socioeconomic status.
  • Related conditions
    • Diabetes
    • Chronic Kidney Disease (albuminuria ± urine protein, eGFR)
    • Familial hypercholesterolaemia
    • Evidence of atrial fibrillation (history, examination, electrocardiogram).

Absolute cardiovascular disease (CVD) risk assessment 

• The Australian Cardiovascular Disease (CVD) Risk Calculator is based on the New Zealand PREDICT equation but has been recalibrated and adapted for use within the Australian population and healthcare context.
• Optional Risk Factors:
  • The calculator allows for additional risk considerations, including:
    • Geographical Area: Determined by residential postcodes, indicating area-level socioeconomic deprivation.
    • Atrial Fibrillation: Inclusion as an independent risk factor.
    • Type 2 Diabetes: With additional considerations for:
      • HbA1c levels
      • Duration since diabetes diagnosis (in years)
      • Urinary albumin-to-creatinine ratio (uACR)
      • Estimated glomerular filtration rate (eGFR)
      • Body Mass Index (BMI)
      • Use of insulin within the previous 6 months
    • Current Medications:
      • Blood pressure-lowering medications
      • Lipid-modifying medications
      • Antithrombotic medications
• Risk Estimation:
  • The calculator provides a 5-year risk estimate for cardiovascular events, categorized as follows:
    • High Risk: ≥10% risk over 5 years
    • Intermediate Risk: 5% to <10% risk over 5 years
    • Low Risk: <5% risk over 5 years
• These categories differ from the 2012 Guidelines for managing absolute CVD risk, as recalibration has resulted in distinct percentile ranges for high, intermediate, and low classifications.
• Limitations:
  • The Aus CVD Risk Calculator is not validated for use in individuals with type 1 diabetes, as it may yield inaccurate estimates in this population.
• Definition of Cardiovascular Disease (CVD):
  • For this guideline, ‘cardiovascular disease’ encompasses the following conditions:
    • Myocardial infarction (MI)
    • Angina
    • Other coronary heart disease (CHD)
    • Stroke
    • Transient ischaemic attack (TIA)
    • Peripheral vascular disease
    • Congestive heart failure
    • Other ischemic CVD-related conditions

Target population

• not known to have CVD or to be at
• clinically determined high risk
• All people aged 45-79 years
• People with diabetes aged 35-79 years
• First Nations people aged 30-79 years
  • (First Nations people aged 18-29 years should have their individual risk factors assessed)

First Nations people aged 18-29 years  : The following CVD risk factors should be screened, as part of an annual health check (or opportunistically) or at least every 2 years :

• smoking status
• blood pressure (BP)
• blood glucose level or glycated haemoglobin (HbA1c)
• estimated glomerular filtration rate (eGFR)
• serum lipids
• urine albumin-to-creatinine ratio (uACR)
• history of familial hypercholesterolaemia (FH).13

Clinically determined high risk:

• Adults with any of the following conditions do not require absolute cardiovascular risk assessment using Equation because they are already known to be at clinically determined high risk of CVD:
  • Moderate or severe CKD
    • persistent proteinuria
    • eGFR <45 mL/min/1.73 m2
  • Familial hypercholesterolaemia
    • most common inherited cause of premature CHD, with a prevalence of 1 in 250
    • People with diagnosed FH are at clinically determined high risk and should be automatically managed as high CVD risk.
    • FH-specific calculators may be useful

The Variables (1st step):

Mandatory
Variable	Application
Age	validated for adults aged 30 to 79 years.
Sex	sex at birth – (there is currently insufficient data to stratify risk for people who are intersex or non-binary sex)
Smoking status	Choose from three categories: never smoked previously smoked currently smokes
Blood pressure (BP)	Systolic blood pressure (SBP) in mmHg. –        Use the average of the last two seated, in-clinic BP measurements. –        Convert home and ambulatory BP readings to in-clinic equivalents before entering into the calculator.
Cholesterol	Enter ratio of total cholesterol (TC) to high-density lipoprotein cholesterol (HDL-C). Use most recent measurements (fasting or non-fasting).
Diabetesa (type 2 only)	status: YES or NO
CVD medicines	CVD medicines used during the 6 months prior to risk assessment (lipid-modifying, BP-lowering, and/or antithrombotic medicines) Lipid-modifying medicines – atorvastatin, fluvastatin, pravastatin, simvastatin, acipimox, bezafibrate, cholestyramine, clofibrate, colestipol, ezetimibe, ezetimibe with simvastatin, gemfibrozil and nicotinic acid. BP-lowering medicines – angiotensin converting enzyme inhibitors, betablockers, thiazide, angiotensin II receptor blockers and calcium channel blockers. Antithrombotic medicines – aspirin, clopidogrel, dipyridamole, prasugrel, ticagrelor, ticlopidine, warfarin, dabigatran, phenindione and rivaroxaban.

Additional diabetes type 2-specific variables (not compulsory, but gives more accurate assessment of risk)
Time since diagnosis of diabetes	Enter time in years.
Glycated haemoglobin (HbA1c)	Enter HbA1c in mmol/mol or % (single non-fasting).
uACRb	Enter urine albumin-creatinine ratio (uACR) (measured in mg/mmol).
eGFRb	Enter eGFR in mL/min/1.73m2
Body mass index(BMI)	Measure weight in kilograms and height in metres.  Calculate BMI: kg/m2.
Insulin	Record use of insulin in the 6 months before risk assessment.

Non- Mandatory
Postcode	Postcode is used to calculate Socio-Economic Indexes for Areas (SEIFA) quintile, and under the discretion of the clinician, may be manually adjusted to better reflect the socioeconomic status of individual patients.
Medical history of atrial fibrillation	Known history of electrocardiogram (ECG) confirmed atrial fibrillation: YES or NO. Both paroxysmal and persistent AF are included in the definition of AF.

 Consider reclassification factors (step 2)

Factor	Potential to reclassify upward or downward
Ethnicity	↑ or ↓
Family history of premature CVD	↑
Chronic kidney disease	↑
Severe mental illness	↑
Coronary artery calcium score	↑ or ↓

reclassify downward

• Coronary artery calcium score of 0
• East Asian ethnicity (Chinese, Japanese, Korean, Taiwanese, or Mongolian ethnicities)

reclassify upward

• Coronary artery calcium score > 99 units, or ≥ 75th percentile for age and sex
• Ethinicity
  • First Nations people
  • Māori
  • Pacific Islander
  • South Asian ethnicity (Indian, Pakistani, Bangladeshi, Sri Lankan, Nepali, Bhutanese or Maldivian ethnicities)
• Family history of premature coronary heart disease (CHD) or stroke in a first-degree
  • female relative aged <65 years or
  • male relative aged <55 years
• Chronic kidney disease
  • eGFR 45–59mL/min/1.73m2 and/or
  • persistent uACR
    • 2.5–25mg/mmol (men) or
  • 3.5–35mg/mmol (women)
• Severe mental illness (current or recent mental health condition requiring specialist treatment, whether received or not, in the 5 years prior to the CVD risk assessment.)

Risk category	Estimated  5‑year CVD riska	Management	Reassessment interval
High	≥10%	Encourage, support and advise a healthy lifestyle.b Prescribe ·        blood pressure-lowering ·        lipid-modifying pharmacotherapy.c	Formal reassessment of CVD risk is not generally required. High-risk status requires clinical management and follow up supported by ongoing communication.
Intermediate	5% to <10%	Encourage, support and advise a healthy lifestyle.b   Consider blood pressure-lowering and lipid-modifying pharmacotherapy, depending on clinical context.	Reassess risk every 2 years if not currently receiving pharmacotherapy to reduce CVD risk. Assess sooner if close to the threshold for high risk, if CVD risk factors worsen, or new CVD risk factors are identified. For First Nations people, reassess every year as part of an annual health check (or opportunistically) or at least every 2 years.
Low	<5%	Encourage, support and advise a healthy lifestyle.b   Pharmacotherapy is not routinely recommended.	Reassess risk every 5 years. Assess sooner if close to the threshold for intermediate risk, if CVD risk factors worsen, or new CVD risk factors are identified.   For First Nations people, reassess every year as part of an annual health check (or opportunistically) or at least every 2 years.

Practice points Communication the Risk

1. Presenting CVD Risk in Patient-Friendly Formats

• Numerical and Frequency-based Formats:
  • Percentage Format: Explain CVD risk as a percentage, e.g., “Based on your profile, you have a 15% risk of having a heart attack or stroke in the next 5 years.”
  • Frequency-based Format: Translate the risk into a frequency, such as, “15 out of 100 people like you will experience a heart attack or stroke in the next 5 years.”
  • Visual Aids: Use 100-person charts to visually represent CVD risk. Highlight the proportion of figures to emphasize those likely to be affected, giving a tangible view of individual risk.

2. Considering Health Literacy and Receptivity

• Assess Understanding: Begin with open-ended questions like, “How comfortable are you with understanding medical risks?” Tailor your explanation accordingly, simplifying complex concepts when necessary.
• Learning Preferences: If the patient prefers visuals, consider using bar graphs or infographics. For auditory learners, verbally reiterate the points and encourage questions to ensure understanding.
• Decision Aids: Provide materials such as booklets, smartphone apps, or printed infographics, allowing patients to review information at their own pace and revisit it during follow-up consultations. Tools like the Australian Absolute Cardiovascular Disease Risk Calculator can serve as excellent aids.

3. Linking Risk to Personal Experiences

• Personal Relevance: Relate the information to recent personal experiences, such as a family member’s CVD diagnosis or the patient’s own life changes. For example, “Since your brother was recently diagnosed with high blood pressure, knowing your own CVD risk may help you manage any genetic factors.”
• Life Stage Considerations: Tailor the discussion to the patient’s life stage. For example, for a patient considering pregnancy, mention, “Managing your CVD risk can improve your health outcomes in pregnancy and protect you in the years to come.”

4. Discussing and Contextualizing CVD Risk Factors

• Address Specific Risk Factors: Identify and discuss relevant risk factors such as smoking, obesity, and alcohol intake. Be transparent about how these factors influence risk, for example, “Quitting smoking could reduce your CVD risk by half within a year.”
• Behavioral Impact: Encourage achievable lifestyle changes by connecting small steps to risk reduction, such as, “Losing 5% of your weight can lower your blood pressure and decrease your risk.”

5. Reinforcing Risk Information Over Multiple Consultations

• Ongoing Dialogues: Schedule follow-up visits to revisit and reassess risk. Repeating information over time reinforces understanding and offers an opportunity to discuss progress and any new health developments.
• Re-evaluation and Encouragement: Regularly update the risk assessment, particularly if the patient implements lifestyle changes or begins new treatments. This keeps the discussion dynamic and encourages continued engagement.

note: Coronary artery calcium (CAC) score

• Function: Measures burden/amount and density of calcium deposits/plaques in coronary vessels.
• Limitation:
  • Cannot determine the degree of stenosis.
  • Therefore, it should not be used as a standalone test for symptomatic patients (e.g., those with potential cardiac angina).
• Reporting:
  • Agatston units (Au): Absolute measure of coronary calcium.
  • Percentile measure: Relative to age- and sex-matched general population.
• Clinical Utility:
  • Aids in individualized cardiovascular event risk prediction.
  • Informs pharmacological treatment decisions.
  • Strong negative predictive value.
• Young Individuals:
• Age Factor:
  • CAC increases with age.
  • Less discriminative in individuals over 75 years due to generally high scores.
• Normal CAC Score (Zero):
  • Consider retesting in 2–5 years to detect score increase and reclassify risk.
  • 25% of patients develop CAC over 5 years.
• When Not to Measure CAC:
  • History of myocardial infarction, revascularization, or known coronary heart disease.
  • Already known high CVD risk.

Clinical applications of CAC testing

Clinical situation	CAC testing	Clinical implications
Population screening for CVD	Not recommended	Low yield of CAC scoring in mass population screening
People with high risk of a cardiovascular event in the next 5 years	Not recommended (neither initial nor repeat test)	CAC score would not alter management: preventive treatment indicated.
People with known CVD	Not recommended (neither initial nor repeat test)	CAC score would not alter management: preventive treatment indicated.
CVD risk assessed as low or intermediate in a person with one or more additional risk factors	Can be considered if available and affordable	Detection of CAC may reclassify risk to a higher level. Score of zero may reclassify risk level to low. Score >99 Au (or ≥75 th percentile for age and sex) may reclassify risk level to a higher level.
Change in intensity of preventive treatment is under consideration	Can be considered if available and affordable to inform discussions with patient	CAC score may alter management.
Previous score of zero	Consider re-testing in 2–5 years	CAC score provides additional monitoring of risk.

note: Others:

Elderly (>79)

• the decision to initiate therapy should be based on clinical judgement which takes into
• account:
  • Likely benefits and risks of treatment
  • Life expectancy, co-morbidities and quality of life
  • Personal values.
• Indications to continue treatment with Statin agent in age over 79 years:
  • Coronary Artery Disease
  • High Coronary Calcium Score
  • Ankle brachial index <0.9
  • hs-CRP >2 mg/L
  • Consider continuing agent even without other indications (NNT 83 to avoid 1 MI in 3-4 years – Savarese (2013) J Am Coll Cardiol 62(22):2090-9

Ankle Brachial Pressure Index (ABPI):

1. Measure of Lower vs. Upper Limb Pressures: ABPI compares blood pressures in the lower and upper limbs.
2. Diagnostic Thresholds:
   • <0.9: Indicates peripheral artery disease (PAD).
   • >1.4: Suggests calcified, non-compressible arteries, often associated with PAD.
3. Correlation with Other Diseases: Linked significantly with coronary and cerebrovascular diseases.
4. Screening Recommendation: Insufficient evidence for routine population screening.
5. Clinical Implication: Abnormal ABPI should prompt management of reversible cardiovascular disease (CVD) risk factors, similar to high CVD risk individuals.

High-sensitivity C-reactive Protein (hsCRP):

1. Inflammatory Marker: Produced by the liver in response to inflammation.
2. Normal Levels: Below 3 mg/L in healthy individuals without acute inflammation.
3. hsCRP Test Sensitivity: Detects levels around 0.3 mg/L, used for CVD risk stratification.
4. Epidemiological Correlation: CRP levels correlate with cardiovascular event risk.
5. Screening Efficiency: Modest impact on preventing CVD events over 10 years, making routine screening questionable.

24-hour Ambulatory Blood Pressure (BP) Monitoring:

1. Measurement Method: BP measured regularly over 24 hours during normal activities and sleep.
2. Diagnostic Utility:
   • Identifies ‘white coat’ hypertension.
   • Detects ‘masked’ hypertension not apparent in clinic measurements.
   • Useful for treatment monitoring.
3. Role in CVD Risk Assessment: Limited; primarily used for BP diagnosis and management.
4. Comparison with Office Readings: Tends to be around 5 mmHg lower than clinic measures, but minor impact on overall CVD risk assessment.