title: Preoperative White Blood Cell Count in Patients with Abdominal Aortic Aneurysms and Its Relation to Survival following Surgery.
abstract: BACKGROUND
  The aim of the present study was to explore whether preoperative white blood cell (WBC) count may predict 30-day mortality and long-term survival following surgery for abdominal aortic aneurysm (AAA). Secondarily, we wanted to assess the potential sex differences in WBC in these patients.
  
  
  METHODS
  The study was carried out as a retrospective cohort study. Patients undergoing surgery for intact and ruptured AAA (rAAA) at our institution consecutively in the time period 1994-2007 were included. Patients were either treated with open aneurysm repair or with endovascular aneurysm repair. Data were collected from the patients' medical records, including laboratory reports for WBC count prior to surgery. Mortality and long-term survival were extracted from The Patient Administrative System.
  
  
  RESULTS
  A total of 988 patients were included, 712 (72%) patients were treated for intact AAA and 276 (28%) underwent surgery for rAAA. Patients with WBC ≥11 ×109/L had a 8.7-fold higher risk of 30-day mortality undergoing surgery for intact AAA compared to patients with WBC <11 ×109/L (95% confidence interval [CI]: 3.2-23.3, P < 0.001). Patients with a high WBC tended to have inferior long-term survival. However, when excluding 30-day mortality, no statistically significant difference was found (hazard ratio, 1.4; 95% CI: 0.9-2.0, P = 0.121). No association between WBC count and 30-day mortality or long-term survival was observed among patients treated for rAAA. We could not identify any sex differences in WBC, neither in intact AAA nor in rAAA. We were not able identify any association between WBC and specific causes of death.
  
  
  CONCLUSIONS
  This study suggests that patients with WBC count ≥11 ×109/L prior to surgery for intact AAA have a higher 30-day mortality compared to patients with WBC <11 ×109/L. We could not identify any substantial difference in long-term survival when excluding 30-day mortality. We did not observe any association between preoperative WBC count and case fatality or long-term survival in patients undergoing surgery for rAAA. No sex differences in WBC were found.
authors.affiliation: Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Vascular Surgery, University Hospital of Trondheim, Trondheim, Norway.
authors.forename: Camilla
authors.initials: C
authors.lastname: Berge
authors.affiliation: Department of Breast and Endocrine Surgery, University Hospital of Trondheim, Trondheim, Norway.
authors.forename: Anne I
authors.initials: AI
authors.lastname: Hagen
authors.affiliation: Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Vascular Surgery, University Hospital of Trondheim, Trondheim, Norway. Electronic address: homyhre@online.no.
authors.forename: Hans O
authors.initials: HO
authors.lastname: Myhre
authors.affiliation: Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Vascular Surgery, University Hospital of Trondheim, Trondheim, Norway.
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Dahl
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000097:blood* / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D001019:Aortic Rupture / Q000097:blood* / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality; D057510:Endovascular Procedures / Q000009:adverse effects / Q000401:mortality; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome