Clinical significance of perioperative Q-wave myocardial infarction: the Emory Angioplasty versus Surgery Trial

J Thorac Cardiovasc Surg. 1996 Dec;112(6):1447-53; discussion 1453-4. doi: 10.1016/S0022-5223(96)70002-8.

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.

MeSH terms

  • Aged
  • Angioplasty, Balloon, Coronary*
  • Coronary Artery Bypass*
  • Coronary Disease / complications
  • Coronary Disease / surgery
  • Coronary Disease / therapy*
  • Creatine Kinase / blood
  • Electrocardiography
  • Female
  • Humans
  • Male
  • Middle Aged
  • Myocardial Infarction / enzymology
  • Myocardial Infarction / etiology
  • Myocardial Infarction / physiopathology*
  • Postoperative Complications / enzymology
  • Postoperative Complications / etiology
  • Postoperative Complications / physiopathology*
  • Prognosis
  • Prospective Studies
  • Randomized Controlled Trials as Topic
  • Retrospective Studies

Substances

  • Creatine Kinase