Significance of raised plasma concentrations of tissue-type plasminogen activator and plasminogen activator inhibitor in patients at risk from ischaemic heart disease.

Tissue-type plasminogen activator (t-PA) is a familiar thrombolytic agent for myocardial infarction. It is perhaps natural, therefore, to think of endogenous t-PA as a "good thing" in terms of protection against coronary thrombosis or other consequences of atheroma. This view is supported by studies that showed a correlation between high concentrations of plasminogen activator inhibitor (PAI-1) and increased coronary risk.' 2 At first sight, however, it is more difficult to reconcile with other studies,35 such as that by Ridker et al,5 which show an equally convincing correlation between cardiovascular risk and increased concentrations of immunologically assayed t-PA.