title: Incremental value of the preoperative echocardiogram to predict mortality and major morbidity in coronary artery bypass surgery.
abstract: BACKGROUND
  Although echocardiography is commonly performed before coronary artery bypass surgery, there has yet to be a study examining the incremental prognostic value of a complete echocardiogram.
  
  
  RESULTS
  Patients undergoing isolated coronary artery bypass surgery at 2 hospitals were divided into derivation and validation cohorts. A panel of quantitative echocardiographic parameters was measured. Clinical variables were extracted from the Society of Thoracic Surgeons database. The primary outcome was in-hospital mortality or major morbidity, and the secondary outcome was long-term all-cause mortality. The derivation cohort consisted of 667 patients with a mean age of 67.2±11.1 years and 22.8% females. The following echocardiographic parameters were found to be optimal predictors of mortality or major morbidity: severe diastolic dysfunction, as evidenced by restrictive filling (odds ratio, 2.96; 95% confidence interval, 1.59-5.49), right ventricular dysfunction, as evidenced by fractional area change <35% (odds ratio, 3.03; 95% confidence interval, 1.28-7.20), or myocardial performance index >0.40 (odds ratio, 1.89; 95% confidence interval, 1.13-3.15). These results were confirmed in the validation cohort of 187 patients. When added to the Society of Thoracic Surgeons risk score, the echocardiographic parameters resulted in a net improvement in model discrimination and reclassification with a change in c-statistic from 0.68 to 0.73 and an integrated discrimination improvement of 5.9% (95% confidence interval, 2.8%-8.9%). In the Cox proportional hazards model, right ventricular dysfunction and pulmonary hypertension were independently predictive of mortality over 3.2 years of follow-up.
  
  
  CONCLUSIONS
  Preoperative echocardiography, in particular right ventricular dysfunction and restrictive left ventricular filling, provides incremental prognostic value in identifying patients at higher risk of mortality or major morbidity after coronary artery bypass surgery.
authors.affiliation: Cardiac Ultrasound Laboratory, Division of Cardiology, Massachusetts General Hospital, Harvard University, Boston, MA 02114, USA. jonathan@afilalo.com
authors.forename: Jonathan
authors.initials: J
authors.lastname: Afilalo
authors.forename: Aidan W
authors.initials: AW
authors.lastname: Flynn
authors.forename: Avi
authors.initials: A
authors.lastname: Shimony
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Rudski
authors.forename: Arvind K
authors.initials: AK
authors.lastname: Agnihotri
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Morin
authors.forename: Cristina
authors.initials: C
authors.lastname: Castrillo
authors.forename: David M
authors.initials: DM
authors.lastname: Shahian
authors.forename: Michael H
authors.initials: MH
authors.lastname: Picard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D015331:Cohort Studies; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000401:mortality*; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D014481:United States; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging