Abstract
Reperfusion therapy for patients with acute myocardial infarction (AMI) is aimed at reopening the occluded infarct-related coronary artery and restoring antegrade flow. This results in the reduction of infarct size and improvement in outcomes. Intracoronary injection of fibrinolytic agents used to be the strategy used for reperfusion therapy. However, intravenous thrombolysis is now considered the treatment of choice for the initial management of patients with AMI in Western countries based on numerous megatrials which showed thrombolysis reduced mortality. The most commonly used fibrinolytic agent is tissue-plasminogen activator (t-PA) which has a higher affinity to fibrin than formerly used agents.
Thrombolytic therapy has failed to achieve at Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 in over 50% of the cases. Percutaneous transluminal coronary angioplasty (PTCA) was introduced to obtain prompt and secure restoration of antegrade coronary flow. Several clinical trials have shown it to be more effective than thrombolysis. PTCA was used as a reperfusion tool in Japan in over 50% of the cases in 1994 and 70% in 1997.
New pharmacological and mechanical interventions have been developed recently to achieve earlier and more successful perfusion. Pilot trials have shown a higher complete reperfusion rate (TIMI flow grade 3) with bioengineered second generation t-PA. Pilot studies of intracoronary stent deployment have shown higher success rates and a lower incidence of restenosis. However, large scale randomized trials will be required to confirm the clinical efficacy and safety of these new interventions.
