The advantages and disadvantages of conservative or invasive therapy were discussed. Conservative therapy was defined as medical therapy such as pharmacological management. Invasive therapy was defined as interventional therapy such as angiography or stents.

Dr. Cannon explained the history of conservative vs. invasive therapy. Conservative therapy meant patients received medical therapy with tissue plasminogen activator, aspirin and heparin and were monitored for rest ischemia. If ischemia occurred, the patient was referred for catheterization or a stress test to determine treatment. Invasive management was either revascularization of the culprit vessel or cardiac artery bypass surgery. In 1992, data comparing conservative and invasive management showed no difference in long-term outcome with either method. As a result, the conservative method became the method of choice.

Due to recent advances in technology and drug development, more recent studies have been conducted to determine if one of these methods may provide a better outcome. The primary endpoint in these studies was death or myocardial infarction.

Dr. Cannon hypothesized that advances in cardiology would favor the invasive strategy over the conservative approach. The invasive approach consisted of routine early catheterization followed by revascularization based on the anatomy. This was compared to the conservative strategy of drug therapy. Patients receiving invasive management showed significantly less number of deaths, myocardial infarctions or rehospitalizations compared to the conservative strategy.

This is in agreement with other studies that have investigated these approaches. For example, the Stent versus Thrombolysis for Occluded Coronary Arteries in Patients with Acute Myocardial Infarction (STOP AMI) study was conducted in 140 patients. Alteplase was chosen as pharmacotherapy for the conservative approach. The invasive approach used a drug along with the invasive therapy: primary stenting and abciximab. The results indicate significant reduction in myocardial infarction size, deaths, recurrent myocardial infarctions and cardiovascular events in the invasive group.

A similar study used aspirin, heparin and balloon angioplasty as the conservative approach. The invasive approach used stenting and IIb/IIIa. The results indicate a 50% reduction in myocardial infarction in patients receiving the invasive strategy. Dr. Cannon concluded current advances in pharmacotherapy and technology favor an invasive approach for the treatment of acute coronary disease.