CORONARY-HEART-DISEASE - REDUCING THE RISK

Coronary heart disease (CHD) is the most common cause of death in most developed countries. Clinical complications of CHD lead to substantia l disability and are a major source of the rising cost of health care. While the incidence of CHD is decreasing in Western Europe, the USA a nd Australia, it is sharply increasing in Central and Eastern Europe a nd to some extent, in Asia and Africa. Worldwide, therefore, the need for effective strategies to prevent CHD has never been greater. In the last decade, much has been learned about strategies for CHD preventio n at the population level and in the individual patient. During this t ime, the results of major trials of lipid-lowering in patients with an d without CHD have become available. Also, data from long-term epidemi ological studies such as the Munster Heart Study has led to formulatio n of the concept of global risk, i.e. the idea that calculation of a p erson's chance of developing CHD must take into account all of the var iables which have been shown to make an independent contribution to ri sk. Since risk factors interact in a multiplicative rather than a simp le additive fashion, calculation of global risk is best undertaken usi ng mathematical algorithms such as those derived from the Munster Hear t Study or the Framingham Heart Study. The Munster algorithm is availa ble in interactive fashion on the Task Force website at http://www.chd -taskforce.com and is reported in detail in the text. Alternatively cl inical assessment may be used to assign the patient to a category of a cceptable risk or to one of three categories of increased risk (small increase, moderate increase, high risk). This document gives detailed consideration to various risk factors for CHD. Age, sex and a personal and family history of CHD are non-modifiable risk factors. The risk f actors hypercholesterolaemia, hypertension and cigarette smoking are c ommon in the general population and are amenable to treatment. Low lev els of HDL-cholesterol are also regarded as a risk marker for CHD. Oth er modifiable variables which should be taken into account in assessin g risk of CHD include body weight, the presence of diabetes mellitus a nd the patient's degree of physical activity. More recently, a large b ody of evidence has accumulated on a link between increased circulatin g levels of triglyceride, lipoprotein(a) (Lp(a)), and fibrinogen and g reater risk for atherosclerosis of the coronary arteries. Recent resea rch has also highlighted the importance of the metabolic syndrome as a common predisposing factor in the development and progression of athe rosclerosis. This condition is characterized by central obesity, hyper insulinism, impaired glucose tolerance, mixed dyslipidaemia, hypertens ion and hyperuricaemia. Peripheral resistance to the action of insulin appears to be the central feature of this condition. Other variables under investigation as CHD risk factors include blood levels of coagul ation factor VIIc, plasminogen activator inhibitor I (PAI-I), and homo cysteine. A new area of research is directed towards the detection of polymorphisms or mutations in genes potentially affecting risk of CHD. Further, attention has recently been given to increased susceptibilit y of low density lipoprotein (LDL) to oxidation as a risk factor for C HD. Finally, areas of current research which may well lead to the iden tification of further risk factors for CHD include investigation of th e function of the endothelium, studies of factors governing the stabil ity of the atherosclerotic plaque and the studies of the predictive va lue of circulating markers of inflammation. These newer risk factors a re described in greater detail in the text. The relationship between n utrition and CHD is now well established based on epidemiological find ings in populations and nutritional intervention trials, and diet rema ins the cornerstone of treatment of hyperlipidaemia. The adoption of a suitable diet by population as a whole is also an important component of strategies for reducing the incidence of CHD. In patients in whom diet alone fails to achieve target levels, lipid-lowering drugs should be used. The efficacy and long-term safety of the statin drugs has be en confirmed in numerous long-term studies. Because of their greatly i ncreased risk of suffering a myocardial infarction, patients with esta blished atherosclerosis should be treated with particular care (second ary prevention). In this document, target levels for lipids are given and it is suggested that the intensity of treatment should depend on t he patient's global risk of CHD. Patients with CHD often stiffer from stroke and vice versa. Since stroke and CHD share many risk factors, s trategies to reduce the incidence of CHD incidence will also lessen th at of stroke. The International Task Force for Prevention of Coronary Heart Disease hopes that general practitioners, cardiologists and all those involved in the management of patients at increased risk of CHD will find this document useful. We also hope that the information cont ained herein will help to provide the scientific rationale for the des ign of effective and efficient strategies to prevent CHD throughout th e world.