Invasive strategy for treatment of myocardial infarction.

The classical approach to the treatment of acute myocardial infarction (MI) has been one of stabilization and complication management. In an effort to optimize treatment, the initiation of the cardiac care unit and the use of antiarrhythmic therapy have succeeded in lowering the mortality rate substantially. More modern concepts are aimed at limiting infarct size and preserving myocardial function. These aims can be achieved medically using intravenous (i.v.) thrombolysis or invasively either with intracoronary (i.c.) thrombolysis, percutaneous transluminal coronary angioplasty (PTCA), or bypass surgery. Although i.c. thrombolysis is more effective than the i.v. route, the necessity for acute coronary catheterization makes it incompatible and difficult for routine use, and thus is usually reserved for cases in which i.v. lysis has failed. Intravenous thrombolysis is becoming the standard approach to MI, and the remaining questions are those of which drug and dosage are optimal and how to approach the patient after thrombolysis. In this regard, we favor a symptom-guided approach, as shown by the TIMI-IIA and European cooperative studies. In patients with ongoing ischemia postlysis, heart catheterization is indicated and a decision regarding PTCA or surgery is then made, depending on anatomy. In patients remaining stable after acute lysis, a predischarge stress may help in selecting patients requiring catheterization. As an alternative invasive approach to acute MI, PTCA may be the quickest and most effective method to recanalize a vessel, but, again, logistical problems make it incompatible in the acute setting. The same is true for bypass surgery, and although extensive improvements have been made in intraoperative myocardial preservation so that a 2% mortality is achievable, it is reserved for patients with extensive ischemia and anatomy unsuitable for PTCA (extensive multivessel or left main disease).