title: Prognostic value of CT angiography in coronary bypass patients.
abstract: OBJECTIVE
  We sought the incremental prognostic value of coronary computed tomography angiography (CTA) in coronary artery bypass graft (CABG) patients.
  
  
  BACKGROUND
  Coronary CTA is a noninvasive and accurate tool for the detection of obstructive coronary artery disease, and coronary CTA appears to have prognostic value in patients without previous revascularization. However, the prognostic value of coronary CTA to predict major adverse cardiac events in CABG patients is unclear.
  
  
  METHODS
  Consecutive CABG patients were prospectively enrolled and cardiac risk was calculated using the National Cholesterol Evaluation Program/Adult Treatment Panel III. Using the severity of native coronary artery disease and graft disease, the number of unprotected coronary territories (UCTs) (0, 1, 2, or 3) was calculated. Patients were followed for cardiac death and nonfatal myocardial infarction. All events were confirmed with death certificates or medical records and reviewed by a clinical events committee.
  
  
  RESULTS
  Between February 2006 and March 2009, 250 consecutive patients were enrolled and followed for a mean of 20.8 ± 10.1 months. At follow-up, 23 patients (9.2%) had major adverse cardiac events (15 cardiac deaths and 8 nonfatal MI). The absence of UCTs conferred a good prognosis with an annual event rate of 2.4%. Conversely, patients with 1, 2, and 3 UCTs had annualized event rates of 5.8%, 11.1%, and 21.7%, respectively. Multivariable analysis showed that UCTs (hazard ratio: 2.08; 95% confidence interval: 1.40 to 3.10; p < 0.001) was a predictor of major adverse cardiac events when adjusted for clinical variables. Examining the receiver-operator characteristic curves, the area under the curve increased from 0.61 to 0.76 when UCTs was combined with clinical variables (p = 0.001).
  
  
  CONCLUSIONS
  Assessing UCTs with coronary CTA appears to have prognostic value in CABG patients and is incremental to clinical variables. Coronary CTA appears to be a promising tool for risk stratification of CABG patients. Further multicenter studies using large CABG cohorts are needed to confirm our findings.
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada. bchow@ottawaheart.ca
authors.forename: Benjamin J W
authors.initials: BJ
authors.lastname: Chow
authors.forename: Osman
authors.initials: O
authors.lastname: Ahmed
authors.forename: Gary
authors.initials: G
authors.lastname: Small
authors.forename: Abdul-Aziz
authors.initials: AA
authors.lastname: Alghamdi
authors.forename: Yeung
authors.initials: Y
authors.lastname: Yam
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: George A
authors.initials: GA
authors.lastname: Wells
mesh_terms: D000368:Aged; D017023:Coronary Angiography / Q000379:methods*; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000401:mortality; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology; D009864:Ontario; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012372:ROC Curve; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D016019:Survival Analysis; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome