Chapter 85: Cardiovascular disease

Cardiovascular disease includes mainly:

• coronary heart disease—myocardial ischaemia (CHAPTER 40)

• cerebrovascular disease—strokes and transient ischaemia (CHAPTER 130)

• peripheral vascular disease (CHAPTER 66)

The number one cause of death in the world is coronary heart disease (CHD),¹ whether from sudden fatal acute coronary events, particularly myocardial infarction (CHAPTER 40) or blocked arteries causing angina and eventually cardiac failure (CHAPTER 88). CHD is responsible for about 3 in 10 deaths in Australia.² However, there has been a pleasing reduction in deaths from coronary heart disease and stroke in recent years because of improved preventive measures. Continuing emphasis on behavioural modification of risk factors and healthy habits is essential to continue this trend.

Modifiable:

• Hypertension (CHAPTER 86)

• Dyslipidaemia (CHAPTER 87)

• Smoking (CHAPTER 21)

• Diabetes (CHAPTER 20) with microalbuminuria

• Obesity (CHAPTER 78)

• Sedentary lifestyle

• Alcohol excess (CHAPTER 21)

• Poor nutrition (CHAPTER 10)

• Mental stress³ (CHAPTER 81)

Non-modifiable

• Family history

• Increasing age

• Male gender

• Social history, inc. cultural/ethnic identity

Related conditions:

• Chronic kidney disease (CHAPTER 31) with microalbuminuria

Assessment of absolute cardiovascular risk

The risk of having a cardiovascular event over the next 5 years (or sometimes 10) is an important assessment which should be estimated before deciding on preventative medication as it greatly influences the pros and cons of screening investigations and treatment. The following target groups should be reassessed every 2 years:

• all adults ≥45 years without known history of CVD

• Aboriginal and Torres Strait Islander people ≥35 years

People for whom a high CVD risk can be assumed (e.g. diabetes, established CVD, hypertension) do not need an absolute CVD risk assessment using the Framingham Risk Equation.⁴

• Blood pressure should be measured in all adults from age 18 years at least every 2 years.

• Adults should have their fasting blood lipids assessed starting at age 45 years, every 5 years (Aboriginal and Torres Strait Islander people from 35 years).

• Adults should be screened for diabetes (fasting plasma glucose or HbA1c) every 3 years from age 40 years (Aboriginal and Torres Strait Islander people from 18 years).

• Adults at high risk should be screened for kidney disease every 1–2 years (ACR ratio and eGFR).

Estimation of cardiovascular risk guidelines based on the key parameters—hypertension, diabetes, smoking, total cholesterol:HDL ratio, age and sex—are presented in FIGURES 85.1 and 85.2. Note that BMI, ethnicity and sedentary lifestyle do not form part of the estimates below (or in many other cardiovascular risk tools) even though in practice they may independently influence risk.

1 Management of lifestyle/behavioural risk factors with goals

All patients who have risk factors should be given lifestyle advice.

Intervention using the 5A framework (CHAPTER 21) is an appropriate practical approach for general practitioners to assist and encourage patients with behavioural risk factor issues to modify⁷ their behaviour, and can be applied to the following:

• smoking—completely stop smoking and avoid second-hand smoke. The death rate from CHD for smokers is about twice that for non-smokers. Smoking cessation, if applicable, is a priority in risk factor reduction.

• alcohol—consume a low-risk quantity (max. 2 standard drinks per day; 1 standard drink for women with hypertension). See guidelines in CHAPTER 21.

• nutrition—maintain healthy eating including limiting saturated fatty acid and trans fat and salt intake to ≤4 g/day.⁷ Aim for a low carbohydrate, healthy fat Mediterranean-type diet. Arrange access to the Heart Foundation Health Information Services and/or refer to a dietitian.

• physical activity—if possible, at least 30 minutes of moderate-intensity physical activity on most days of the week (min. 150 minutes/week). If feasible arrange an appointment with an accredited exercise physiologist as well as a local activity program.

• healthy weight—waist measurement (men <94 cm, women <80 cm; BMI range 18.5–25). The benefits of weight reduction include improved insulin resistance, decreased LDL-C and triglycerides, and increased HDL-C.

• stress management—encourage promotion of recreation, relaxation techniques, meditation and social support. Treat anxiety disorders and depression with counselling if appropriate.

Additionally, patients at high risk (>15% 5-year CV risk or previous CV event) should have specific parameters treated.

2 Management of biomedical risk factors with targets

• Blood pressure: <130/80 mmHg

  Lipids: total C <4 mmol/L; LDL-C

  <2 mmol/L; HDL-C ≥1.0 mmol/L; non-HDL-C

  <2.5 mmol/L; TG <2.0 mmol/L⁵

• Lowering LDL-C is essential to reduce cardiovascular risk; every decrease of 1 mmol/L reduces all-cause mortality by 10%⁸

• Diabetes: maintain optimal blood sugar level 4.0–6.0 mmol/L (ideal); compare NHMRC 6.1–8.0 mmol/L; HbA1c ≤7%

• Antiplatelet agent: patients with a previous CV event should take aspirin 75–150 mg/day unless contraindicated. However, aspirin is of limited benefit and not routinely recommended in those at high risk (>15% 5-year or diabetes) who have not had a CV event.⁹

National Vascular Disease Prevention Alliance, Guidelines for the management of absolute cardiovascular disease risk. <www.heartfoundation.org.au/images/uploads/publications/Absolute-CVD-Risk-Full-Guidelines.pdf>, accessed April 2018.