title: Monitoring for myocardial ischemia during noncardiac surgery. A technology assessment of transesophageal echocardiography and 12-lead electrocardiography. The Study of Perioperative Ischemia Research Group.
abstract: OBJECTIVE
  Transesophageal echocardiography (TEE) and 12-lead electrocardiography (ECG) are sophisticated techniques that are increasingly being used to monitor for myocardial ischemia during noncardiac surgery. We examined whether the routine use of these techniques has incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes when compared with preoperative clinical data and intraoperative monitoring using continuous two-lead bipolar ECG.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Veterans Affairs medical center.
  
  
  METHODS
  A total of 332 men undergoing noncardiac surgery who had or were at high risk for coronary artery disease.
  
  
  METHODS
  TEE, 12-lead ECG, and two-lead ECG were performed continuously during noncardiac surgery (47% vascular, 53% nonvascular). Monitoring results were not available to anesthesiologists or surgeons, and data were blindly analyzed after surgery.
  
  
  METHODS
  Perioperative ischemic outcomes (cardiac death, nonfatal myocardial infarction, unstable angina).
  
  
  RESULTS
  In a subset of 285 patients who were adequately studied by all three techniques, 111 patients (39%) were identified as having intraoperative myocardial ischemia (by one or more monitoring techniques). By univariate analysis, intraoperative ischemia was associated with all perioperative cardiac outcomes, including ischemic outcomes, congestive heart failure, and ventricular tachycardia (P less than or equal to .02 for each of the three monitoring techniques). However, when monitoring results for TEE and 12-lead ECG were added to a multivariate model that included preoperative clinical data and continuous two-lead ECG results, the incremental value of TEE was small (odds ratio, 2.6; 95% confidence interval [CI], 1.2 to 5.7; P = .02) and that of 12-lead ECG was not significant (odds ratio, 1.5; 95% CI, 0.6 to 3.8). Furthermore, when the multivariate analysis was repeated with only ischemic outcomes, neither TEE nor 12-lead ECG retained significant associations (odds ratio, 2.2; 95% CI, 0.5 to 9.4, and odds ratio, 1.1; 95% CI, 0.2 to 6.1, respectively).
  
  
  CONCLUSIONS
  When compared with preoperative clinical data and intraoperative monitoring using two-lead ECG, routine monitoring for myocardial ischemia with TEE or 12-lead ECG during noncardiac surgery has little incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes.
authors.affiliation: Department of Medicine, University of California, San Francisco 94143-0214.
authors.forename: M J
authors.initials: MJ
authors.lastname: Eisenberg
authors.forename: M J
authors.initials: MJ
authors.lastname: London
authors.forename: J M
authors.initials: JM
authors.lastname: Leung
authors.forename: W S
authors.initials: WS
authors.lastname: Browner
authors.forename: M
authors.initials: M
authors.lastname: Hollenberg
authors.forename: J F
authors.initials: JF
authors.lastname: Tubau
authors.forename: I M
authors.initials: IM
authors.lastname: Tateo
authors.forename: N B
authors.initials: NB
authors.lastname: Schiller
authors.forename: D T
authors.initials: DT
authors.lastname: Mangano
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000209:etiology; D003327:Coronary Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D016757:Death, Sudden, Cardiac / Q000209:etiology; D004452:Echocardiography; D004562:Electrocardiography; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000209:etiology; D016017:Odds Ratio; D011183:Postoperative Complications / Q000209:etiology; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013673:Technology Assessment, Biomedical