Objective To investigate the long-term prognostic influence of patency of the Methods One thousand two hundred and sixty seven cases of acute myocardial infarction with thrombolytic treatment between July 1991 and January 1995 in 36 collaborative hospitals were follwed-up after discharge with a total follow-up rate of 84.5%. Patency of infarct-related coronary artery was assessed by uniform clinical criteria. Eight hundred and forty three patients with patency were followed up for 16.0 +/- 10.4 months and 424 patients without pateney for 19.2 +/- 12.22. Death or up to the end of March, 1995 was used as the end point. Results Comparisons of patients with patent versus non-patent infarct-related coronary artery during follow-up showed: (1) Cardiac death rate was 2.85% in patients with patency while 4.72% in those without patency (logrank test, P > 0.1). (2) Three-year survival rates calculated by Kaplan-Meier curve were 91.6% and 73.9% respectively (logrank test, P < 0.001). (3) Incidence of reinfarction were 5.7% and 5.9% respectively (P < 0.05). (4) Patients with class III-IV NYHA cardiac function occurred in 11.3% and 17.9% respectively (P < 0.01). (5) By Cox regression model analysis patency of infarct-related coronary artery, recurrent infarction, age and infarct sites were independent prognostic factors. Survival probability increased by 33.5% in patients with patency compared to those without patency. Conclusion It is evident that pateney of infarct-related coronary artery could improve long-term survival.