title: Development of a risk prediction model for transfusion in carotid endarterectomy and demonstration of cost-saving potential by avoidance of "type and screen".
abstract: OBJECTIVE
  Preoperative testing for carotid endarterectomy (CEA) often includes blood typing and antibody screen (T&S). In our institutional experience, however, transfusion for CEA is rare. We assessed transfusion rate and risk factors in a national clinical database to identify a cohort of patients in whom T&S can safely be avoided with the potential for substantial cost savings.
  
  
  METHODS
  With use of the National Surgical Quality Improvement Program database, transfusion events and timing were established for all elective CEAs in 2012-2013. Comorbidities and other characteristics were compared for patients receiving intraoperative or postoperative transfusion and those who did not. After random assignment of the total data to either a training or validation set, a prediction model for transfusion risk was created and subsequently validated.
  
  
  RESULTS
  Of 16,043 patients undergoing CEA in 2012-2013, 276 received at least one transfusion before discharge (1.7%); 42% of transfusions occurred on the day of surgery. Preoperative hematocrit <30% (odds ratio [OR], 57.4; 95% confidence interval [CI], 29.6-111.1), history of congestive heart failure (OR, 2.8; 95% CI, 1.1-7.1), dependent functional status (OR, 2.7; 95% CI, 1.5-5.1), coagulopathy (OR, 2.5; 95% CI, 1.7-3.6), creatinine concentration ≥1.2 mg/dL (OR, 2.3; 95% CI, 1.6-3.3), preoperative dyspnea (OR, 2.0; 95% CI, 1.4-3.1), and female gender (OR, 1.6; 95% CI, 1.1-2.3) predicted transfusion. A risk prediction model based on these data produced a C statistic of 0.85; application of this model to the validation set demonstrated a C statistic of 0.81. In the validation set, 93% of patients received a score of 6 or less, corresponding to an individual predicted transfusion risk of 5% or less. Omitting a T&S in these patients would generate a substantial annual cost saving for National Surgical Quality Improvement Program hospitals.
  
  
  CONCLUSIONS
  Whereas T&S are commonly performed for patients undergoing CEA, transfusion after CEA is rare and well predicted by a transfusion risk score. Avoidance of T&S in this low-risk population provides a substantial cost-saving opportunity without compromise of patient care.
authors.affiliation: Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass; Klinik für Allgemein-, Viszeral-, Gefäss- und Thoraxchirurgie, Kantonsspital Baselland, Liestal, Switzerland.
authors.forename: Lars
authors.initials: L
authors.lastname: Stangenberg
authors.affiliation: Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: Thomas
authors.initials: T
authors.lastname: Curran
authors.affiliation: Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: Fahad
authors.initials: F
authors.lastname: Shuja
authors.affiliation: Klinik für Allgemein-, Viszeral-, Gefäss- und Thoraxchirurgie, Kantonsspital Baselland, Liestal, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Rosenberg
authors.affiliation: Division of Vascular Anesthesia and Perioperative Echocardiography, Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: Feroze
authors.initials: F
authors.lastname: Mahmood
authors.affiliation: Division of Vascular and Endovascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass. Electronic address: mscherme@bidmc.harvard.edu.
authors.forename: Marc L
authors.initials: ML
authors.lastname: Schermerhorn
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001788:Blood Grouping and Crossmatching / Q000191:economics*; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D001803:Blood Transfusion / Q000191:economics; D002340:Carotid Artery Diseases / Q000175:diagnosis / Q000191:economics / Q000601:surgery*; D017046:Cost Savings; D003362:Cost-Benefit Analysis; D016208:Databases, Factual; D016894:Endarterectomy, Carotid / Q000009:adverse effects / Q000191:economics*; D005260:Female; D017048:Health Care Costs; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018579:Patient Selection; D019106:Postoperative Hemorrhage / Q000191:economics / Q000209:etiology / Q000517:prevention & control*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome; D014481:United States; D019564:Unnecessary Procedures / Q000191:economics*