Composite Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries ( GUSTO ) moderate or severe bleeds were modestly increased ( 2.4 % versus 1.7 % ; HR , 1.438 ; P = 0.234 ) but severe bleeds were not more frequent ( 0.3 % versus 0.5 % ; HR , 0.549 ; P = 0.471 ) in the prolonged treatment group .