Acute intervention during myocardial infarction in patients with prior coronary bypass surgery.

T hrombolytic intervention with or without coronary angioplasty is becoming widely accepted as standard therapy for patients who present early with acute myocardial infarction, Thrombolytic therapy has been shown to improve left ventricular function* and reduce mortality.2 Nearly all clinical trials of myocardial reperfusion have excluded patients with a history of coronary artery bypass grafting. Furthermore, the only available data for the use of thrombolytic agents in this patient group consist of case reports of intracoronary thrombolytic agents3 and a small series of intravenous thrombolytic agents4 There are no published data for the use of angioplasty or combined thrombolysis and angioplasty in patients with acute infarction after bypass surgery. Considering the increasing number of patients undergoing coronary artery bypass grafting and their propensity for future cardiac events,5 important questions regarding the optimal treatment strategy for prior coronary artery bypass patients come to bear. Accordingly, we reviewed our experience in the treatment of patients after coronary artery bypass surgery in the setting of evolving myocardial infarction. Records from the University of Michigan Cardiac Catheterization Laboratory were reviewedfrom January I, 1984, to December 30, 1987, and a database of patients with a history of coronary artery bypass grafting and acute myocardial infarction was tabulated. Acute myocardial infarction was diagnosed when an episode of characteristic chest pain lasting 130 minutes was associated with a transient, temporally appropriate increase of the total serum creatine phosphokinase above the upper limit of normal with myocardial isoenzyme fraction greater than twice normal. Data were compiled regarding the presence and type of standard electrocardiogram tracings at the time of infarction. Details of acute interventions, when performed, were accumulated, including those concerning the infarct-related vessel and whether or not the patient was treated with thrombolytic agents, direct angioplasty or a combination of the 2. Status of the infarct-related vessel after intervention was also noted. Follow-up data regarding hospital discharge, repeat catheterization, exercise stress testing and the needforfurther intervention, including repeat bypass surgery, were also obtained. Data are expressed as mean f 1 standard deviation. A comparison of the efficacy of acute intervention as defined by infarct-related vessel patency after intervention was estimated by examining a cohort of patients who presented with acute myocardial infarction and had