Impact of Circadian Variations on Efficacy of Thrombolytic Therapy for Acute Myocardial Infarction / 中国循环杂志

ABSTRACT

Objective:To study the impact of circadian variations on the efficacy of urokinase (UK) therapy in patients with acute myo- cardial infarction (AMI). Methods:Ninety-five AMI patients presenting with chest pain≤3 hours were given UK theerapy.They were divided into two groups according to their symptom onset timelate morning group (601—1200,n=42) and other time group (1201—600 next day,n=53).We obtained elbow venous blood samples at 3 time pointsbefore UK therapy,30 and 60 minutes after UK ini- tiation respectively.Serum levels of AT-Ⅲ,PAI-1 Ag,PAI-1 activity,D-D,?_2-APL Ag were examined.The repatency of culprit vessels was also determined 120 minutes after UK administration. Results:①UK therapy in the late morning group(23 out of 42 patients) had lower repatency rate compared with the other time group(40 out of 53 patients) (P＜0.05).②The late morning group had a higher serum levels of PAI-1 Ag before UK thera- py (39.822?4.737 versus 37.406?4.696,P＜0.05).③The serum level of PAI-1 antigen at aforementioned three time points was 36.054?4.456,35.242?4.143 and 35.355?4.135 in reperfused patients compared with 42.7822?3.277,42.398? 4.565 and 42.395?5.223 in nonnperfused patients.The activity of PAI-1 was 15.234?2.671,13.256?4.532 and 11.830? 3.905 in reperfused patients versus 17.0743?3.665,16.447?4.469 and 16.928?4.248 in nonreperfused patients at three time points.Both of PAI-1 antigen and its activity was consistently lower in reperfused AMI patients as compared with the nonper- fused patients before and 30,120 minutes after UK therapy(P＜0.05).There was no significant difference in the serum levels of ?_2-APL Ag,D-D,and AT-Ⅲ activity between the two populations (P＞0.05). Conclusion:Our data showed circadian variations have an impact on the efficacy of UK therapy in patients with AMI,which suggests that there may exist a phenomenon of “morning resistance to thrombolysis therapy” due to increased level of PAI-1 Ag and activity.