CLINICAL-SIGNIFICANCE OF PERIOPERATIVE Q-WAVE MYOCARDIAL-INFARCTION -THE EMORY ANGIOPLASTY VERSUS SURGERY TRIAL

Objective: The primary end point of the Emery Angioplasty versus Surge ry Trial was a composite of three events: death, Q-wave infarction, an d a new large defect on 3-year postoperative thallium scan. This study examines the clinical significance of Q-wave infarction in the surgic al cohort (194 patients) of the Emery trial. Methods: Twenty patients (10.3%) with Q-wave infarctions were identified: 13 patients had infer ior Q-wave infarctions and seven patients had anterior, lateral, septa l, or posterior Q-wave infarctions (termed anterior Q-wave infarctions ). Results: In the inferior Q-wave infarction group, postoperative car diac catheterization (at 1 year or 3 years) in 11 patients revealed no rmal ejection fraction (ejection fraction > 55%) in 10 (91%), no wall motion abnormalities in 10 (91%), and all grafts patent in 10 (91%). I n the anterior Q-wave infarction group, postoperative catheterization in six patients revealed normal ejection fractions in five (83%), no w all motion abnormalities in three (50%), and all grafts patent in thre e (50%). Average peak postoperative creatine kinase MB levels were as follows: no Q-wave infarction (n = 174) 37 +/- 43 IU/L, inferior Q-wav e infarction 40 +/- 27 IU/L, and anterior Q-wave infarction 58 +/- 38 IU/L. Mortality in the 20 patients with Q-wave infarctions was 5% (1/2 0) at 3 years; in patients without a Q-wave infarction it was 6.3% (11 /174) (p = 0.64). Of 17 patients with a Q-wave infarction who underwen t postoperative catheterization, 11 (65%) had a normal ejection fracti on, normal wall motion, and all grafts patent with an uneventful 3-yea r postoperative course. Conclusions: The core laboratory screening of postoperative electrocardiograms, particularly in the case of inferior Q-wave infarctions, appears to identify a number of patients as havin g a Q-wave infarction with minimal clinical significance. Q-wave infar ction identified in the postoperative period seems to be a weak end po int with little prognostic significance and therefore not valuable for future randomized trials.