title: Acute cholecystitis: risk factors for conversion to an open procedure.
abstract: BACKGROUND
  Laparoscopic cholecystectomy is one of the most common general surgical procedures performed. Conversion to an open procedure (CTO) is associated with increased morbidity and length of stay. Patients presenting with acute cholecystitis are at higher risk for CTO. Studies have attempted to examine risk factors for CTO in patients who undergo laparoscopic cholecystectomy for acute cholecystitis but are limited by small sample size. The aim of this study was to identify preoperative variables that predict higher risk for CTO in patients presenting with acute cholecystitis.
  
  
  METHODS
  Patients undergoing laparoscopic cholecystectomy for acute cholecystitis from 2005-2011 were identified from the American College of Surgeons' National Surgical Quality Improvement Program Participant Use File. Patients who underwent successful laparoscopic surgery were compared with those who required CTO. Demographics, comorbidities, and 30-d outcomes were analyzed. Multivariable logistic regression was used for variables with P value <0.1, with CTO used as the dependent variable.
  
  
  RESULTS
  A total of 7242 patients underwent laparoscopic cholecystectomy for acute cholecystitis. CTO was reported in 436 patients (6.0%). Those who required conversion were older (60.7 ± 16.2 versus 51.6 ± 18.0, P = 0.0001) and mean body mass index was greater (30.8 ± 7.6 versus 30.0 ± 7.3, P = 0.033) compared with those whose procedure was completed laparoscopically. Vascular, cardiac, renal, pulmonary, neurologic, hepatic disease, diabetes, and bleeding disorders were more prevalent in CTO patients. Mortality (2.3% versus 0.7%, P < 0.0001), overall morbidity (21.8% versus 6.0%, P < 0.0001), serious morbidity (14.9% versus 3.8%, P < 0.0001), reoperation (3.4% versus 1.4%, P = 0.001), and surgical site infection (9.2% versus 1.8%, P < 0.0001) rates, as well as length of stay (8.6 ± 13.0 versus 3.4 ± 6.7, P < 0.0001) were greater in those requiring CTO. The following factors were independently associated with CTO: age (odds ratio [OR], 1.01, P = 0.015), male gender (OR, 1.77, P = 0.005), body mass index (OR, 1.04, P < 0.0001), preoperative alkaline phosphatase (OR, 1.01, P = 0.0005), white blood cell count (OR, 1.06, P = 0.0001), and albumin (OR, 0.52, P = 0.0001).
  
  
  CONCLUSIONS
  CTO for acute cholecystitis remains low but not clinically negligible. The identified risk factors can potentially guide management and patient selection for delayed intervention for acute cholecystitis.
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina.
authors.forename: Megan
authors.initials: M
authors.lastname: Sippey
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina.
authors.forename: Marysia
authors.initials: M
authors.lastname: Grzybowski
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Manwaring
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Kasten
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina.
authors.forename: William H
authors.initials: WH
authors.lastname: Chapman
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina.
authors.forename: Walter E
authors.initials: WE
authors.lastname: Pofahl
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina.
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Pories
authors.affiliation: Department of Surgery, Brody School of Medicine at East Carolina University, Greenville, North Carolina. Electronic address: spaniolask@ecu.edu.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Spaniolas
mesh_terms: D000328:Adult; D000368:Aged; D017081:Cholecystectomy, Laparoscopic / Q000706:statistics & numerical data*; D041881:Cholecystitis, Acute / Q000601:surgery*; D061887:Conversion to Open Surgery / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
keywords: ACS-NSQIP; Acute Cholecystitis; Conversion; Laparoscopic Cholecystectomy