International Task Force for Prevention of
Coronary Heart Disease

CORONARY HEART DISEASE: REDUCING THE RISK

2.5 The risk review

After the patient has been assessed as detailed in sections 2.1 (Personal and family history) to 2.3 (Biochemical and laboratory risk factors), his/her risk of developing CHD can be estimated. This assessment is of central importance, since it determines the goals of therapy and thus the intensity of treatment. As in all areas of medical practice, the risk review implies the clinical judgement of the individual patient and his/her unique circumstances. Today the doctor can draw on a body of evidence from epidemiological studies and from prospective clinical trials to inform clinical assessment and to guide therapeutic decision-making. Both approaches may be used in complementary fashion to assess the individual risk and to decide on the correct modality and intensity of treatment.
The goal of risk assessment is to determine an appropriate type and intensity of treatment. In the case of lipid risk fac-tors, this implies deciding how intensive a diet is needed, whether a drug is required and if so at what dosage, and what target levels to aim for. This may be achieved by judging whether the patient is at average risk or whether she/he falls into one of the three grades of increased risk indicated below (2.5.1.1 to 2.5.1.3). This may be undertaken using clinical judgment, i.e. by recording the risk factors present and noting their number and severity or by employing quantitative risk assessment, using risk algorithms from the Framingham or PROCAM (Figure 2) studies.

2.5.1 Grades of increased risk

2.5.1.1 Small increase in risk

• presence of one risk factor of moderate degree, e.g. (in a middle-aged man) plasma total cholesterol 200-300 mg/dL (5.2-7.8 mmol/L) with no non-lipid risk factors, OR
• plasma cholesterol:HDL-cholesterol ratio 4 to 5, OR
• smoking about 10 cigarettes per day but no other risk factors, OR
• quantitative risk estimate in the third quintile of the PROCAM ¹⁴. algorithm ¹⁵. which takes into account nine risk factors (see section 2.5.2, The risk calculator). The risk of a CHD event is about 0.3% per year in middle-aged men (Figure 2).

2.5.1.2 Moderate increase in risk

• presence of one risk factor of severe degree, e.g. a middle-aged man who smokes about 20 cigarettes per day, OR
• presence of two risk factors of moderate degree, e.g. a middle-aged man with a plasma cholesterol 200-300 mg/dL (5.2-7.8 mmol/L) plus HDL-cholesterol less than 40 mg/dL (1 mmol/L) or obesity, OR
• quantitative risk estimate in the fourth quintile of the PROCAM algorithm. The risk of a CHD event is about 0.7% per year in middle-aged men, OR
• presence of type 1 or type 2 diabetes mellitus without macrovascular complications.

2.5.1.3 High risk

• patients with a history of myocardial infarction are at high risk and fall into the category of secondary prevention. At similar levels of cholesterol and other risk factors, the patient with CHD is several times more likely to suffer a further CHD event than the person with no evidence of cardiovascular disease.
• atherosclerosis of the coronary arteries as evidenced by: angina pectoris or ischaemic changes in the resting or exercise ECG, atherosclerosis of the carotid arteries as evidenced by a definite transient ischaemic attack, a carotid bruit, or an atherosclerotic plaque in the carotid artery on ultrasound examination; or atherosclerosis of peripheral arteries as revealed by the presence of intermittent claudication, an absent foot pulse, or doppler sonography, OR
• presence of three or more risk factors e.g. moderate hypertension and plasma cholesterol 200-300 mg/dL (5.2-7.8 mmol/L) and smoking about 10 cigarettes per day, OR
• presence of two risk factors of severe degree e.g. plasma cholesterol > 300 mg/dL (7.8 mmol/L) and smoking 20 cigarettes per day, OR
• presence of a major genetic hyperlipidaemia e.g. familial hypercholesterolaemia or type III (remnant) hyperlipidaemia, OR
• presence of type 1 or 2 type diabetes mellitus with macrovascular complications, OR
• quantitative risk estimate in fifth quintile of the PROCAM algorithm. The risk of a CHD event is about 2.3% per year in middle-aged men.

2.5.2 The Risk Calculator

The risk calculator programme (available on the Task Force homepage at: http://www.chd-taskforce.com or http://chd-taskforce.de) may be used to quantify global risk based on the nine independent risk determinants defined in the Münster Heart Study (PROCAM) ¹⁵. . This facilitates clinical decision-making as is shown in the following illustrative cases. Patients 1 and 3 are rare in clinical practice but illustrate the concept of global risk; most patients falls between these two extremes.

Example 1. Solitary elevated LDL-cholesterol (180 mg/dL (4.7 mmol/L))
A 45-year-old man with systolic blood pressure 130 mmHg, HDL-cholesterol 49 mg/dL, triglyceride 90 mg/dL, LDL-cholesterol 180 mg/dL, non-smoker, non-diabetic, no family history of myocardial infarction, no history of angina pectoris: the risk of an acute event (fatal or non-fatal MI, sudden cardiac death) in this man, despite a high LDL-cholesterol level, is only 14.1 per 1000 in 8 years, or 0.18% per year, i.e. he falls into the second quintile of risk, i.e. "small increase in risk".

Example2. Multiple risk factors, elevated LDL-cholesterol (180 mg/dL (4.7 mmol/L))<(i>
A 45-year-old man with systolic blood pressure 180 mmHg, HDL-cholesterol 30 mg/dL, triglyceride 250 mg/dL, LDL-cholesterol 180 mg/dL, smoker, non-diabetic, positive family history of MI, positive history of angina pectoris: the risk of an acute event in this man is 625 per 1000 in 8 years or 8% per year, i.e. he falls into highest quintile of risk.

Example 3. Muliple risk factors, normal LDL-cholesterol (100 mg/dL (2.6 mmol/L))
A 45-year-old man with systolic blood pressure 180 mmHg, HDL-cholesterol 30 mg/dL, triglyceride 250 mg/dL, LDL-cholesterol 100 mg/dL, smoker, non-diabetic, family history of MI, positive history of angina pectoris: the risk of an acute event in this man, despite the normal LDL-cholesterol, is 267 per 1000 in 8 years or 3% per year, i.e. he too falls into the highest quintile of risk.