Acute Coronary Symptoms

Risk Factors

Acute coronary syndromes (ACS) are usually the clinical consequence of the formation of an occlusive thrombus at the site of a ruptured or eroded atherosclerotic plaque in a coronary artery.

As such, factors that increase the risk of atherosclerotic coronary artery disease (CAD) also increase the risk of ACS. However, it is important to note that atherosclerotic plaques vary in their stability. Some are less stable than others, and, hence, more likely to rupture.¹ There is evidence that hypercholesterolaemia, smoking and raised fibrinogen levels contribute to plaque instability.¹ Classical risk factors for CAD are as follows:²

Nonmodifiable risk factors

Increased age: Atherosclerosis is rare in childhood, yet almost universal among elderly people from western countries.

Male gender: CAD is generally more common in men than in women, although rates of atheroma in postmenopausal women approach those in men.

Positive family history: Risk is increased in those with a first-degree relative in whom ischaemic heart disease developed before the age of 50 years.

Modifiable risk factors

Smoking: Smoking is thought to be responsible for approximately 17% and 20% of CAD-related deaths in women and men, respectively.² Risk is proportional to the number of cigarettes smoked, and declines to almost normal after 10 years’ abstention.

Diet exercise and bodyweight: Poor diet (high in fat, low in antioxidants), lack of physical exercise and obesity are all associated an increased risk of CAD. Conversely, weight loss, through dietary modification and increased exercise, has been shown to reduce the incidence of cardiovascular disease and diabetes/insulin resistance.²

Hypertension: Systolic and diastolic hypertension are both associated with an increased risk of CAD.² Among patients who qualify for drug therapy on the basis of overall cardiovascular risk, target BP is 140/90 mmHg. In patients with diabetes or existing cardiovascular disease, a lower target of 130/80 mmHg is recommended.³

Hyperlipidaemia: The association between plasma cholesterol levels and atherosclerotic disease is well established. Target levels of total and LDL-cholesterol vary according to overall level of risk; in general, levels should be below 5 mmol/L and 3 mmol/L, respectively,³ but lower targets (<4.5 mmol/L and <2.5 mmol/L) apply to high-risk patients (established cardiovascular disease, diabetes and those with markedly raised lipid levels). Low levels of HDL-cholesterol (<1.0 mmol/L in men and <1.2 mmol/L in women) and elevated fasting levels of triglycerides (>1.7 mmol/L) are associated with increased cardiovascular risk, but no specific treatment goals have as yet been defined for these lipids.³

Diabetes mellitus: Diabetes is strongly associated with cardiovascular disease. In patients with type 2 diabetes, each 1% reduction in HbA1c is associated with a 14% reduction in the rate of MI, and lower all-cause mortality.⁴ Guidelines from the International Diabetes Federation-Europe currently recommend an HbA₁c target of =6.5%, with fasting and post-prandial glucose levels not exceeding 6.0 and 7.5 mmol/L, respectively.⁴