The significance of elevated plasma lipids in relation to the prevention of ischaemic heart disease.

In this report an attempt is made to assess the value of reducing elevated plasma lipids in the treatment and prevention of ischaemic heart disease. The main relationships between lipids and atheroma formation and between lipids and intravascular thrombosis are outlined, although no general review is undertaken. While there is probably a causal relationship between hypercholesterolaemia and the early development of atheroma, the nature of the association between elevated plasma lipids and ischaemic heart disease is uncertain. Epidemiological studies have indicated that certain environmental factors can be positively correlated with ischaemic heart disease and one of these is the intake of saturated fat. Although there is no entirely satisfactory method for reducing elevated plasma lipids over an indefinite period, a strict diet substituting unsaturated for saturated fats is the best at present available.Certain long-term dietary and hormonal studies of the benefit of reducing elevated plasma lipids in patients with ischaemic heart disease are reviewed. Provisionally, it is concluded that continued reduction of plasma lipids does not improve prognosis once myocardial infarction has occurred. Thus, the next step is a study of the value of reducing elevated plasma lipids in otherwise apparently healthy men. Some of the problems involved in the establishment of such a study are discussed.