CURRENT ISSUES CONCERNING THROMBOLYTIC THERAPY FOR ACUTE MYOCARDIAL-INFARCTION

Data are now available from three large-scale randomized trials that d irectly compare the risks and benefits of thrombolytic agents in acute myocardial infarction. In the interpretation of results hom the Grupp o Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico ( GISSI-2) trial and its International Extension, the Third Internationa l Study of Infarct Survival (ISIS-3), and the Global Utilization of St reptokinase and Tissue Plasminogen Activator for Occluded Coronary Art eries (GUSTO-1) trial, there are areas of both agreement and controver sy. It is generally agreed that the agents most commonly used in the U nited States-tissue-type plasminogen activator (t-PA), streptokinase a nd anisoylated plasminogen streptokinase activator complex (APSAC)-all reduce mortality when given to patients with acute evolving myocardia l infarction. Further, it is clear that thrombolytic therapy given to such patients presenting up to 12 h after onset of symptoms reduces th e mortality rate by similar to 20%, that aspirin therapy for patients presenting up to 24 h reduces the mortality rate by similar to 23% and that the benefits of thrombolytic therapy and aspirin are additive. F inally, and of most importance, the earlier administration as well as the more widespread use of thrombolytic therapy and aspirin would save many more lives. The totality of evidence clearly indicates that stre ptokinase produces significantly fewer strokes and cerebral hemorrhage s than either t-PA or APSAC, Whether or not accelerated t-PA has a sma ll advantage for mortality is less conclusive. At present, any small d ifferences in safety, efficacy and ease of administration of different thrombolytic agents are far outweighed by the large benefits that wou ld accrue from earlier administration and wider utilization of any of these drugs.