title: Prognostic capabilities of coronary computed tomographic angiography before non-cardiac surgery: prospective cohort study.
abstract: OBJECTIVE
  To determine if coronary computed tomographic angiography enhances prediction of perioperative risk in patients before non-cardiac surgery and to assess the preoperative coronary anatomy in patients who experience a myocardial infarction after non-cardiac surgery.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  12 centers in eight countries.
  
  
  METHODS
  955 patients with, or at risk of, atherosclerotic disease who underwent non-cardiac surgery.
  
  
  METHODS
  Coronary computed tomographic angiography was performed preoperatively; clinicians were blinded to the results unless left main disease was suspected. Results were classified as normal, non-obstructive (<50% stenosis), obstructive (one or two vessels with ≥ 50% stenosis), or extensive obstructive (≥ 50% stenosis in two vessels including the proximal left anterior descending artery, three vessels, or left main).
  
  
  METHODS
  Composite of cardiovascular death and non-fatal myocardial infarction within 30 days after surgery (primary outcome). This was the dependent variable in Cox regression. The independent variables were scores on the revised cardiac risk index and findings on coronary computed tomographic angiography.
  
  
  RESULTS
  The primary outcome occurred in 74 patients (8%). The model that included both scores on the revised cardiac risk index and findings on coronary computed tomographic angiography showed that coronary computed tomographic angiography provided independent prognostic information (P=0.014; C index=0.66). The adjusted hazard ratios were 1.51 (95% confidence interval 0.45 to 5.10) for non-obstructive disease; 2.05 (0.62 to 6.74) for obstructive disease; and 3.76 (1.12 to 12.62) for extensive obstructive disease. For the model with coronary computed tomographic angiography compared with the model based on the revised cardiac risk index alone, with 30 day risk categories of <5%, 5-15%, and >15% for the primary outcome, the results of risk reclassification indicate that in a sample of 1000 patients that coronary computed tomographic angiography would have resulted appropriately in 17 net patients receiving a higher risk estimation among the 77 patients who would have experienced the primary outcome (P<0.001). Coronary computed tomographic angiography, however, would have resulted inappropriately in 98 net patients receiving a higher risk estimation, among the 923 patients who would not have experienced the primary outcome (P<0.001). Among patients who had a perioperative myocardial infarction, preoperative coronary anatomy showed extensive obstructive disease in 31% (22/71), obstructive disease in 41% (29/71), non-obstructive disease in 24% (17/71), and normal findings in 4% (3/71).
  
  
  CONCLUSIONS
  Though findings on coronary computed tomographic angiography can improve estimation of risk for patients who will experience perioperative cardiovascular death or myocardial infarction, findings are more than five times as likely to lead to an inappropriate overestimation of risk among patients who will not experience these outcomes. Perioperative myocardial infarction occurs across the spectrum of coronary artery disease, suggesting that there could be several pathophysiologic mechanisms.
authors.affiliation: Population Health Research Institute, David Braley Cardiac, Vascular, and Stroke Research Institute, Hamilton, ON L8L 2X2, Canada shetht@mcmaster.ca.
authors.forename: Tej
authors.initials: T
authors.lastname: Sheth
authors.affiliation: Department of Anesthesia and Intensive Care, Chinese University of Hong Kong, Hong Kong, SAR, China.
authors.forename: Matthew
authors.initials: M
authors.lastname: Chan
authors.affiliation: Department of Medicine, Division of Cardiology, University of Alberta, 2C2 Walter Mackenzie Centre, Edmonton, AB T6G 2B7, Canada.
authors.forename: Craig
authors.initials: C
authors.lastname: Butler
authors.affiliation: Departments of Medicine (Cardiology) and Radiology, University of Ottawa Heart Institute, Ottawa, ON K1Y 4W7, Canada.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Chow
authors.affiliation: Division of Cardiology, Department of Medicine, St. Joseph's Healthcare, McMaster University, Hamilton, ON L8N 4A6, Canada.
authors.forename: Vikas
authors.initials: V
authors.lastname: Tandon
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St Louis, Washington, MO 63110, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Nagele
authors.affiliation: Inkosi Albert Luthuli Central Hospital-Department of Radiology, Cato Manor, Durban, 4091, South Africa.
authors.forename: Ayesha
authors.initials: A
authors.lastname: Mitha
authors.affiliation: Division of General Internal Medicine,University of Western Ontario, London, ON N6A 5A5, Canada.
authors.forename: Marko
authors.initials: M
authors.lastname: Mrkobrada
authors.affiliation: Department of Medicine, Jagiellonian University Medical College, 31-027 Krakow, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Szczeklik
authors.affiliation: Department of Biomedical Imaging, University Malaya Research Imaging Centre, Faculty of Medicine, University Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Yang
authors.initials: Y
authors.lastname: Faridah
authors.affiliation: University of Kwazulu-Natal, Glenwood, Durban, 4041, South Africa.
authors.forename: Bruce
authors.initials: B
authors.lastname: Biccard
authors.affiliation: Diagnostic Imaging, Hamilton Health Sciences, Jurvanski Hospital, Hamilton, ON L8V 1C3, Canada.
authors.forename: Lori K
authors.initials: LK
authors.lastname: Stewart
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON L8S 3Z5, Canada.
authors.forename: Diane
authors.initials: D
authors.lastname: Heels-Ansdell
authors.affiliation: Departments of Clinical Epidemiology and Biostatistics and Medicine, McMaster University, Hamilton , ON L8S 3Z5, Canada.
authors.forename: P J
authors.initials: PJ
authors.lastname: Devereaux
mesh_terms: D000368:Aged; D015331:Cohort Studies; D017023:Coronary Angiography; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology / Q000517:prevention & control*; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control*; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013514:Surgical Procedures, Operative