Lipids of plasma and of clots produced under standardized conditions from platelet poor plasma and from PTT reagent were examined in patients with acute myocardial infarction (AMI) and in normal persons. No differences were found, which excludes a significant influence of fibrinogen, but not of platelets, on clot-lipid binding. The main lipid fractions were therefore also estimated in clots produced from platelet rich native and citrate plasma. These and the individual phospholipid fractions were determined also in the corresponding plasmas and high density lipoproteins (HDL). Plasma of patients with AMI contained more monoglycerides and lecithin but less lysolecithin. This fraction was particularly low in the HDL and corresponded with a decrease of cholesterol esters. Lipid fractions of clots did not differ significantly, whether they were obtained from citrate or native plasma. Clots in AMI contained significantly more triglycerides (TG) suggesting an increased affinity of TG-rich lipoproteins to platelet rich clots. An increased and changed lipid content of clots could inhibit lytic enzymes essential for the removal of clots. HDL cholesterol-esters in AMI were negatively correlated with the main clot lipid fractions.
