[A study on the circadian variation of tissue-type plasminogen activator and its rapid inhibitor in patients with coronary heart disease].

In our study, we measured resting tissue-type plasminogen activator(t-PA) activity and resting plasminogen activator inhibitor-1 (PAI-1) activity in 15 healthy men and in 20 patients (male) with coronary heart disease in the morning and evening. Resting t-PA activity was lower (P < 0.05) in controls and was significantly lower (P < 0.001) in patients in the morning compared with that in the evening. In contrast, PAI-1 activity was significantly higher (P < 0.001) in controls and was also significantly higher (P < 0.001) in patients in the morning compared with that in the evening. t-PA activity in patients compared with that in controls was significantly lower (P < 0.05) in the morning and the evening; PAI-1 activity in patients compared with that in controls was significantly higher (P < 0.001) in the morning and the evening. However, t-PA activity was significantly lower (P < 0.05) and PAI-1 activity was significantly higher (P < 0.05) in patients with myocardial infarction compared with anginal patients in the morning. Applying this clinical phenomenon that myocardial infarction and angina have often occurred in the morning, the relationship between time of onset of myocardial infarction and circadian variation of t-PA and PAI-1 was discussed.