Improved early infarct-related vessel patency after thrombolytic therapy.

The major goal of reperfusion strategies in patients with acute myocardial infarction is to achieve patency of the infarct-related artery . Improvement in ventricular function and survival are related to initial and continued potency of this artery . The greater initial patency of the infarct-related artery after intravenous recombinant tissue-type plasminogen activator (r(-PA) compared with that achieved with intravenous streptokinase in the Thrombolysis in Myocardial Infarction (TIM[) trial (I) led to the selection of rt-PA as the thrombolytic agent of choice in the United States. With current intravenous thrombolytic strategies, the highest potency rate achieved is 75% . Early use of intravenous heparin and the use ofcombined thrombolytic regimens have failed to break through this ceiling (2-4), which may be a result of several factors. These include complexity of the atherosclerotic plaque with intramural plaque hemorrhage (5), ongoing platelet deposition into the thrombus with resistance to thrombolysis iii1 as well as inadequate thrombolytic effectiveness or dose of the chosen thrombolytic agent . The failure of current intravenous thmmbulylie strategies to achieve a higher patency rate of the infarct-related artery has led to several adjunctive and alternative strategies for reperfusion, Rescue angioplasty for patients with failed intravenous thrombolysis has been evaluated in several trials (7) . However, initial results have been disappointing because of a relatively high rate of complications including death . The failure of rescue angioplasty may be related to platelet activation, particularly aftcrrt-PA and mechanical trauma to the residual thrombus, resulting in reocclusion . Several investigators (8) have achieved a high patency rate by using direct coronary angioplasty without intravenous thrumhntytic therapy ("direct" angioplasty) . A patency rate of >90% has been achieved with a relatively low complication rate with this strategy . Although feasible, this strategy has only limited applicability because of the limited availability of angioplasty facilities and laboratories willing to operate on