title: Clinical significance of perioperative Q-wave myocardial infarction: the Emory Angioplasty versus Surgery Trial.
abstract: OBJECTIVE
  The primary end point of the Emory Angioplasty versus Surgery Trial was a composite of three events: death, Q-wave infarction, and a new large defect on 3-year postoperative thallium scan. This study examines the clinical significance of Q-wave infarction in the surgical cohort (194 patients) of the Emory trial.
  
  
  METHODS
  Twenty patients (10.3%) with Q-wave infarctions were identified: 13 patients had inferior Q-wave infarctions and seven patients had anterior, lateral, septal, or posterior Q-wave infarctions (termed anterior Q-wave infarctions).
  
  
  RESULTS
  In the inferior Q-wave infarction group, postoperative cardiac catheterization (at 1 year or 3 years) in 11 patients revealed normal ejection fraction (ejection fraction >55%) in 10 (91%), no wall motion abnormalities in 10 (91%), and all grafts patent in 10 (91%). In the anterior Q-wave infarction group, postoperative catheterization in six patients revealed normal ejection fractions in five (83%), no wall motion abnormalities in three (50%), and all grafts patent in three (50%). Average peak postoperative creatine kinase MB levels were as follows: no Q-wave infarction (n = 174) 37 +/- 43 IU/L, inferior Q-wave 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% (1/20) 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 underwent postoperative catheterization, 11 (65%) had a normal ejection fraction, normal wall motion, and all grafts patent with an uneventful 3-year 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 having a Q-wave infarction with minimal clinical significance. Q-wave infarction identified in the postoperative period seems to be a weak end point with little prognostic significance and therefore not valuable for future randomized trials.
authors.affiliation: Joseph P. Whitehead Department of Surgery, Emory University School of Medicine, Atlanta, Ga., USA.
authors.forename: G T
authors.initials: GT
authors.lastname: Hodakowski
authors.forename: J M
authors.initials: JM
authors.lastname: Craver
authors.forename: E L
authors.initials: EL
authors.lastname: Jones
authors.forename: S B
authors.initials: SB
authors.lastname: King
authors.forename: R A
authors.initials: RA
authors.lastname: Guyton
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000150:complications / Q000601:surgery / Q000628:therapy*; D003402:Creatine Kinase / Q000097:blood; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000201:enzymology / Q000209:etiology / Q000503:physiopathology*; D011183:Postoperative Complications / Q000201:enzymology / Q000209:etiology / Q000503:physiopathology*; D011379:Prognosis; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies
chemical_list: D003402:Creatine Kinase