Protein C levels in ischaemic heart disease.

Protein C is a circulating glycoprotein with anticoagulant properties. Functional and immunological levels of protein C were determined in 34 cases of ischaemic heart disease and 12 healthy age-matched controls. The sensitive colorimetric assay was used to determine the functional levels and ELISA for antigenic levels. Mean protein C activity and antigenic levels were found to be elevated in these patients as compared to controls. Protein C levels in the three individual subgroups-acute myocardial infarction, previous myocardial infarction and chronic stable angina pectoris-were also raised as compared to controls. The elevation was significant in the case of the acute myocardial infarction group. These results further support the hypothesis that the body synthesises increased amounts of protein C in ischaemic heart disease to compensate for the hypercoagulable state that exists in this disorder, thus playing a protective role.