title: Development of a risk index for prediction of mortality after open aortic aneurysm repair.
abstract: OBJECTIVE
  Open infrarenal abdominal aortic aneurysm (oAAA) repair is associated with significant morbidity and mortality. Although there has been a shift toward endovascular repair, many patients continue to undergo an open repair due to anatomic considerations. Tools currently existing for estimation of periprocedural risk in patients undergoing open aortic surgery have certain limitations. The objective of this study was to develop a risk index to estimate the risk of 30-day perioperative mortality after elective oAAA repair.
  
  
  METHODS
  Patients who underwent elective oAAA repair (n = 2845) were identified from the American College of Surgeons' 2007 to 2009 National Surgical Quality Improvement Program (NSQIP), a prospective database maintained at >250 centers. Univariable and multivariable analyses were performed to evaluate risk factors associated with 30-day mortality after oAAA repair and a risk index was developed.
  
  
  RESULTS
  The 30-day mortality after oAAA repair was 3.3%. Multivariable analysis identified six preoperative predictors of mortality, and a risk index was created by assigning weighted points to each predictor using the β-coefficients from the regression analysis. The predictors included dyspnea (at rest: 8 points; on moderate exertion: 2 points; none: 0 points), history of peripheral arterial disease requiring revascularization or amputation (3 points), age >65 years (3 points), preoperative creatinine >1.5 mg/dL (2 points), female gender (2 points), and platelets <150,000/mm(3) or >350,000/mm(3) (2 points). Patients were classified as low (<7%), intermediate (7%-15%), and high (>15%) risk for 30-day mortality based on a total point score of <8, 8 to 11, and >11, respectively. There were 2508 patients (88.2%) patients in the low-risk category, 278 (9.8%) in the intermediate-risk category, and 59 (2.1%) in the high-risk category.
  
  
  CONCLUSIONS
  This risk index has excellent predictive ability for mortality after oAAA repair and awaits validation in subsequent studies. It is anticipated to aid patients and surgeons in informed patient consent, preoperative risk assessment, and optimization.
authors.affiliation: Department of Surgery, Creighton University, Omaha, Neb.
authors.forename: Bala
authors.initials: B
authors.lastname: Ramanan
authors.forename: Prateek K
authors.initials: PK
authors.lastname: Gupta
authors.forename: Abhishek
authors.initials: A
authors.lastname: Sundaram
authors.forename: Himani
authors.initials: H
authors.lastname: Gupta
authors.forename: Jason M
authors.initials: JM
authors.lastname: Johanning
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Lynch
authors.forename: Jason N
authors.initials: JN
authors.lastname: MacTaggart
authors.forename: Iraklis I
authors.initials: II
authors.lastname: Pipinos
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality / Q000601:surgery*; D016009:Chi-Square Distribution; D003661:Decision Support Techniques; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014656:Vascular Surgical Procedures / Q000009:adverse effects / Q000401:mortality*