Update on mechanical revascularization in acute myocardial infarction: which role and when?
Mechanical revascularization in the acute myocardial infarction by primary angioplasty has several advantages over thrombolytic therapy. The short-term patency rates of the infarct-related artery range from 95 to 99% and a normal flow is achieved in more than 90% of the cases. This prompt and effective reperfusion is probably responsible for the improved prognosis with primary angioplasty. The better outcome after primary angioplasty is observed both in low- and in high-risk patients, in all ages and in patients presenting late (>6 h) after the chest pain. Pooled analysis of randomized studies, show that primary angioplasty as compared to thrombolysis, has a lower incidence of death, stroke and reinfarction. Additional advantages of primary PTCA include the possibility of reperfusion in patients in whom lysis is contraindicated or less effective (e.g. patients in cardiogenic shock, or with prior coronary artery bypass surgery) and the ability to provide prognostic information helpful in the patient triage. Thus, primary PTCA results in better outcome than thrombolysis when performed in centers with success rates comparable to those achieved in the randomized trials. Further studies are still needed to assess its long-term efficacy. Several randomized trials are underway to assess the role of stents and the use of more potent antiplatelet drugs, as the GPIIb/IIIa receptor blockers, in adjunct to balloon angioplasty in the treatment of acute myocardial infarction.