Objective To investigate whether intrapericardial urokinase irrigation along with pericardiocentesis could prevent peri-cardial constriction in patients with infectious exudative pericarditis. Methods A total of 94 patients diagnosed as infectious exudative pericarditis （34 patients with purulent pericarditis and 60 with tuberculous pericarditis

the disease courses of all patients were less than 1 month）

44 males and 50 females

aged from 9 to 66 years （mean 45.4 ± 14.7 years）

were consecutively recruited from 1993 to 2002. All individuals were randomly given either intrapericardial urokinase along with conventional treatment in study group

or conventional treatment alone （including pericardiocentesis and drainage） in control group. The dosage of urokinase ranged from 200 000 to 600 000 U （mean 320 000 ± 70 000 U）. The immediate effects were detected by pericardiography with sterilized air and diatrizoate meglumine as contrast media. The long-term investigation depended on the telephonic survey and echocardiographic examination. The duration of following-up ranged from 8 to 120 months （mean 56.8 ± 29.0 months）. Results Percutaneous intrapericardial urokinase irrigation promoted complete drainage of pericardial effusion

signifi-cantly reduced the thickness of pericardium （from 3.1 ± 1.6 mm to 1.6 ± 1.0 mm in study group

P < 0.001; from 3.4 ± 1.6 mm to 3.2 ± 1.8 mm in control group

P > 0.05

respectively）

and alleviated the adhesion. Intrapericardial bleeding related to fibrinolysis was found in 6 of 47 patients with non-blood pericardial effusion and no systemic bleeding and severe puncture-related complication was observed. In follow-up

there was no cardiac death

and pericardial constriction events were observed in 9 （19.1%） of study group and 27 （57.4%） of control group. Cox analysis illustrated that urokinase could significantly reduce the occurrence of pericardial constriction （relative hazard coefficient = 0.185

P < 0.0001）. Conclusion The early employment of intrapericardial fibrinolysis with urokinase and pericardiocentesis appears to be safe and effective in preventing the development of pericardial constriction in patients with infectious exudative pericarditis.