[Lipids and acute coronary syndromes]

Eccentric atherogenic plaques which cause only insignificant narrowing of the diameter of coronary arteries are the cause of 60-80% of all acute coronary syndromes. The plaque becomes unstable (vulnerable) due to cytokines released by macrophages in the lipid rich core. Weakening of the fibrous capsule of the core then leads to rupture of the plaque and subsequently to intracoronary thrombosis with a wide spectrum of ischaemia or even necrosis of the myocardium. Secondary preventive studies (4S, LIPID, CARE), morphological non-mortality studies (e.g. AVERT, REGRESS, LCAS) and primary preventive studies (WOSCOPS, AFCAPS/TexCAPS) revealed that statins reduce significantly, as compared with placebo, total and LDL-cholesterol by 20-35% and lead in subsequent years to a significant decline of the relative risk of the general and coronary mortality and morbidiy by 20-40%. They prevent progression and may lead to regression of coronary sclerosis. They do not act by mere reduction of the cholesterol level but also by their extralipid effects which stabilize the plaque. 80% of patients with coronary syndrome have cholesterol levels between 6.0 and 7.5 mmol/l, similarly as ca 40% of healthy middle aged persons. The difference is in the risk caused either by the presence of ischaemic heart disease or in healthy subjects by the cumulation of several coronary risk factors. A special risk group are the remaining 20% patients. They include subjects with a cholesterol level above 8 mmol/l who must be treated more aggressively, similarly as patients after a venous aortocoronary bypass. Subjects with slightly elevated LDL-cholesterol values but high triacylglycerol levels and lower HDL-cholesterol levels have also an atherogenic risk. This applies not only to postmenopausal women, elderly people, obese and diabetic subjects, hypertensive subjects with insulin resistance but also to young subjects. In the latter reduction of triacylglycerols is indicated. In coronary patients a combination of statins and fibrates may be used. Basic hypolipidaemic treatment for reduction of the atherothrombotic risk are statins. Despite statin treatment the prospective mortality and morbidity of coronary patients is still high and it is necessary to make an effort to achieve target lipid levels. Recent studies provide new findings, further progress and stricter therapy are foreseen.