Fatty acid composition of platelets and of plasma lipid esters in relation to platelet function in patients with ischaemic heart disease.

Serum lipoproteins, fatty acids in plasma lipid esters and in platelet phospholipids were assessed in 64 patients with ischaemic heart disease (IHD) and in 67 controls. Hyperlipoproteinemia (HLP) (VLDL triglycerides greater than 1.4 mmol/l and/or LDL cholesterol greater than 5.2 mmol/l) was found in 64% of the patients. In the plasma lipid esters the relative concentrations of saturated and monounsaturated fatty acids as well as dihomo-gammalinolenic acid were higher in the IHD patients whereas the linoleic acid concentrations were lower. The altered fatty acid pattern was apparent both in patients with and without HLP. In the platelet phospholipids there was a relative increase of oleic acid and a decrease of stearic acid. The relative content of eicosapentaenoic acid was slightly reduced whereas the linoleic acid concentrations were unchanged compared to the controls. Platelet aggregation induced by ADP and collagen was enhanced in the IHD patients. The lowest threshold value for ADP-induced aggregation was found in the normolipidemic patients. Since there were almost no differences in the relative contents of the long-chain polyunsaturated fatty acids in the platelet phospholipids between patients and controls it is concluded that mechanisms other than the prostaglandin-mediated pathway may contribute to the increased platelet aggregation in IHD patients.