title: Risk index for predicting perioperative stroke, myocardial infarction, or death risk in asymptomatic patients undergoing carotid endarterectomy.
abstract: OBJECTIVE
  The latest guidelines recommend performance of carotid endarterectomy (CEA) on asymptomatic patients with high-grade carotid stenosis, only if the combined perioperative stroke, myocardial infarction (MI), or death risk is ≤3%. Our objective was to develop and validate a risk index to estimate the combined risk of perioperative stroke, MI, or death in asymptomatic patients undergoing elective CEA.
  
  
  METHODS
  Asymptomatic patients who underwent an elective CEA (n = 17,692) were identified from the 2005-2010 National Surgical Quality Improvement Program, a multicenter, prospective database. Multivariable logistic regression analysis was performed with primary outcome of interest being the composite of any stroke, MI, or death during the 30-day periprocedural period. Bootstrapping was used for internal validation. A risk index was created by assigning weighted points to each predictor using the β-coefficients from the regression analysis.
  
  
  RESULTS
  Fifty-eight percent of the patients were men with a median age of 72 years. Thirty-day incidences of stroke, MI, and death were 0.9% (n = 167), 0.6% (n = 108), and 0.4% (n = 72), respectively. The combined 30-day stroke, MI, or death incidence was 1.8% (n = 324). On multivariable analysis, six independent predictors were identified and a risk index created by assigning weighted points to each predictor using the β-coefficients from the regression analysis. The predictors included age in years (<60: 0 point; 60-69: -1 point; 70-79: -1 point; ≥80: 2 points), dyspnea (2 points), chronic obstructive pulmonary disease (3 points), previous peripheral revascularization or amputation (3 points), recent angina within 1 month (4 points), and dependent functional status (5 points). Patients were classified as low (<3%), intermediate (3%-6%), or high (>6%) risk for combined 30-day stroke, MI, or death, based on a total point score of <4, 4-7, and >7, respectively. There were 15,249 patients (86.2%) in the low-risk category, 2233 (12.6%) in the intermediate-risk category, and 210 (1.2%) in the high-risk category.
  
  
  CONCLUSIONS
  The validated risk index can help identify asymptomatic patients who are at greatest risk for 30-day stroke, MI, and death after CEA, thereby aiding patient selection.
authors.affiliation: Department of Surgery, University of Wisconsin Hospital & Clinics, Madison, WI, USA.
authors.forename: Prateek K
authors.initials: PK
authors.lastname: Gupta
authors.forename: Bala
authors.initials: B
authors.lastname: Ramanan
authors.forename: Jason N
authors.initials: JN
authors.lastname: Mactaggart
authors.forename: Abhishek
authors.initials: A
authors.lastname: Sundaram
authors.forename: Xiang
authors.initials: X
authors.lastname: Fang
authors.forename: Himani
authors.initials: H
authors.lastname: Gupta
authors.forename: Jason M
authors.initials: JM
authors.lastname: Johanning
authors.forename: Iraklis I
authors.initials: II
authors.lastname: Pipinos
mesh_terms: D000368:Aged; D058070:Asymptomatic Diseases; D016893:Carotid Stenosis / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D003661:Decision Support Techniques; D016894:Endarterectomy, Carotid / Q000009:adverse effects* / Q000401:mortality*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000401:mortality*; D016017:Odds Ratio; D018579:Patient Selection; D059035:Perioperative Period; D011237:Predictive Value of Tests; D012042:Registries; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000401:mortality*; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology