Ischaemic heart disease and atherosclerosis, prevention

I20-I25

Major risk factors for ischaemic cardio- and cerebrovascular disease:

  • Diabetes mellitus.
  • Hypertension.
  • Central obesity (waist circumference): men ≥ 102 cm, women ≥ 88 cm.
  • Smoking.
  • Dyslipidaemia:
    • Total cholesterol > 5.0 mmol/L, or
    • LDL > 3 mmol/L, or
    • HDL < 1 mmol/L in men and < 1.2 mmol/L in women.
  • Family history of premature cardiovascular disease in first degree male relatives < 55 years and in first degree female relatives < 65 years.
  • Age: men > 55 years, women > 65 years.
  • Psychological stress.

LoEII [1]

GENERAL MEASURES

Lifestyle modification, especially smoking cessation, is essential and often has greater beneficial impact on prognosis than vascular interventions and medications.

All persons should be encouraged to make the following lifestyle changes as appropriate:

  • Smoking cessation.
  • Weight reduction in overweight patients, i.e. BMI > 25 kg/m².
  • Maintain ideal weight, i.e. BMI < 25 kg/m².
  • Reduce alcohol intake to no more than 2 standard drinks/day
  • Follow a prudent eating plan i.e. low saturated fat, high fibre and unrefined carbohydrates, with adequate fresh fruit and vegetables.
  • Moderate aerobic exercise, e.g. 40 minutes brisk walking at least 3 times a week.

Calculation of risk of developing cardiovascular disease over 10 years (in the absence of cardiovascular disease)

To derive the absolute risk as the percentage of patients who will have a myocardial infarction over 10 years, add the points for each risk category (Section A). The risk associated with the total points is then derived from Section B.

SECTION A

Age
(years) 		MEN WOMEN
30-34 0 0
35-39 2 2
40-44 5 4
45-49 6 5
50-54 8 7
55-59 10 8
60-64 11 9
65-69 12 10
70-74 14 11
75-79 15 12
Total cholesterol (mmol/L) MEN WOMEN
<4.1 0 0
4.1-5.1 1 1
5.2-6.2 2 3
6.2-7.2 3 4
>7.2 4 5
HDL cholesterol (mmol/L) MEN WOMEN
>1.5 -2 -2
1.3-1.5 -1 -1
1.2-1.3 0 0
0.9-1.1 1 1
<0.9 2 2
MEN WOMEN
Smoker 4 3
Diabetic* 3 4

*Type 2 diabetics > 40 years, qualify for statin therapy irrespective of risk score.

MEN WOMEN
Systolic BP (mmHg) Untreated Treated Untreated Treated
<120 -2 0 -3 -1
120-129 0 2 0 2
130-139 1 3 1 3
140-149 2 4 2 5
150-159 2 4 4 6
≥160 3 5 5 7

SECTION B

Total points
10-year risk % MEN 10-year risk % WOMEN
<1 ≤–3 <1 ≤–2
1.1 –2 1.0 –1
1.4 –1 1.2 0
1.6 0 1.5 1
1.9 1 1.7 2
2.3 2 2.0 3
2.8 3 2.4 4
3.3 4 2.8 5
3.9 5 3.3 6
4.7 6 3.9 7
5.6 7 4.5 8
6.7 8 5.3 9
7.9 9 6.3 10
9.4 10 7.3 11
11.2 11 8.6 12
13.2 12 10.0 13
15.6 13 11.7 14
18.4 14 13.7 15
21.6 15 15.9 16
25.3 16 18.5 17
29.4 17 21.5 18
>30 ≥18 24.8 19
28.5 20
>30 21+

MEDICINE TREATMENT

Indications for lipid lowering medicine therapy

Patients with any of the following factors are at a relatively high risk for a cardiovascular event and should receive lipid lowering therapy:

  • Established atherosclerotic disease:
    • ischaemic heart disease
    • peripheral vascular disease
    • atherothrombotic stroke
  • Type 2 diabetes with age >40 years.
  • Diabetes for >10 years.
  • Diabetes with chronic kidney disease (eGFR <60 mL/minute).

LoEI [2]

Patients with any of the following factors are also potentially at risk for cardiovascular disease (other than the categories above):

  • diabetes mellitus
  • hypertension
  • central obesity: waist circumference ≥ 94 cm (men) and ≥ 80 cm (women)
  • smoking
  • age: men > 55 years of age, women > 65 years of age

These patients should be managed according to their 10–year risk of a cardiovascular event as calculated using either:

A. BMI–based risk assessment – see PHC STGs and EML, section: Prevention of ischaemic heart disease and atherosclerosis, or

B. Framingham risk score (cholesterol-based assessment) – see tables above.

Management is based on the patient’s 10-year risk of a cardiovascular event:

  • < 10% risk: lifestyle modification and risk assess patient every 5 years
  • 10–20% risk: lifestyle modification and risk assess patient annually
  • ≥ 20% risk: lifestyle modification and start statin treatment

Note:

  • Lipid lowering medicines should be given to those with a high risk of CVD even if cholesterol is within the desirable range.
  • HMGCoA reductase inhibitors (statins), according to table below:
INDICATION HMGCOA REDUCTASE INHIBITOR (STATIN) DOSE
A: Primary prevention  - no existing CVD
  • Type 2 diabetes with age >40 years.

  • Diabetes for >10 years.

  • Diabetes with chronic kidney disease.

  • ≥ 20% 10-year risk of cardiovascular event.
    		•  HMGCoA reductase inhibitors
    (statins), e.g.:
  • Simvastatin, oral, 10 mg at night.
    		•
  • Patients on protease inhibitors.

    • (Risks as above, after switching to atazanavir – see section below).
  • Atorvastatin, oral, 10 mg at night.
    		•
    B: Secondary prevention – existing CVD
  • Ischaemic heart disease.

  • Atherothrombotic stroke.

  • Peripheral vascular disease.
    		•  HMGCoA reductase inhibitors (statins), e.g.:
  • Simvastatin, oral, 40 mg at night

    • LoEI [3]
  • Patients on protease inhibitors.
    		•
  • Atorvastatin, oral, 10 mg at night.

    • LoEI [4]
  • Patients on amlodipine (and not on protease inhibitor).
    		•
  • Simvastatin, oral, 10–20 mg at night.

    • LoEIII [5]
  • If patient complains of muscle pain.
    		•  Reduce dose:
  • HMGCoA reductase inhibitors (statins), e.g.:

  • Simvastatin, oral, 10 mg at night.

    • OR
    Consult specialist for further management.

    LoEIII [6]

    Note: Lipid-lowering medicines must always be used in conjunction with ongoing lifestyle modification.

    Protease inhibitor-induced dyslipidaemia:

    • Certain antiretroviral medication, particularly protease inhibitors, can cause dyslipidaemia. Fasting lipid levels should be done 3 months after starting lopinavir/ritonavir. Lopinavir/ritonavir is associated with a higher risk of dyslipidaemia (specifically hypertriglyceraemia) than atazanavir/ ritonavir.
    • Patients at high risk (>20% risk of developing a CVD event in 10 years) should switch to atazanavir/ritonavir and repeat the fasting lipid profile in 3 months.
    • Patients with persistent dyslipidaemia despite switching, qualify for lipid lowering therapy. Criteria for initiating lipid lowering therapy are the same as for HIV-uninfected patients. Many statins (including simvastatin) cannot be used with protease inhibitors, as protease inhibitors inhibit the metabolism of the statin resulting in extremely high blood levels.
    • Patients who fail to respond to lifestyle modification and have dyslipidaemia treat with:
      • Atorvastatin, oral, 10 mg at night.

    REFERRAL

    • Random cholesterol >7.5 mmol/L.
    • Fasting (14 hours) triglycerides >10 mmol/L.