title: Portomesenteric venous thrombosis following major colon and rectal surgery: incidence and risk factors.
abstract: BACKGROUND
  Portomesenteric venous thrombosis (PMVT) is an uncommon complication of abdominal surgery. The objective of this study was to assess PMVT risk factor profiles and patient outcomes after colorectal surgery.
  
  
  METHODS
  A single center retrospective review of patients undergoing colorectal surgery was performed (2007-2012). PMVT was defined as thrombus within the portal, splenic, or superior mesenteric vein on computed tomography (CT). Inferior mesenteric vein thrombosis was excluded. Independent samples t test was used to compare data variables between PMVT and non-PMVT patients. Univariate and multivariate logistic regression analyses were used to assess PMVT risk factors.
  
  
  RESULTS
  There were 1,224 patients included (mean age 62 years, male = 566). Elective bowel resection was performed for colon carcinoma (n = 302), rectal carcinoma (n = 112), ulcerative colitis (n = 125), Crohn's disease (n = 78), polyps (n = 117), and diverticulitis (n = 215). Patients undergoing gynecological resections and emergent laparotomies were included (n = 275). Thirty-six patients (3%) were diagnosed with PMVT by CT: 17/36 on initial presentation and 19/36 by expert radiologist review. Patients with PMVT were younger (53 vs. 62 years, p = 0.001) with higher BMI (30.5 vs. 26.7, p < 0.001) and thrombocytosis (464 vs. 306, p < 0.001) compared to patients without PMVT. Univariate logistic regression identified younger age (p < 0.001), obesity (p < 0.001), ulcerative colitis (p < 0.001), thrombocytosis, (p < 0.001) and proctocolectomy as significant predictors of PMVT. Stepwise multivariate logistic regression identified that obesity (p < 0.001), thrombocytosis, (p < 0.001) and restorative proctocolectomy (p = 0.001) were still significant predictors. No patients in the PMVT group suffered bowel infarction and no related mortalities occurred. Thirty-day readmission rates were higher in the PMVT group (53% vs. 17%, p < 0.01).
  
  
  CONCLUSIONS
  BMI ≥ 30 kg/m(2), thrombocytosis, and restorative proctocolectomy were significant predictors of PMVT. Initial diagnostic studies showed a PMVT rate of 1.4%; however, after expert focused radiologic review, the actual rate was 3%. Thus, the diagnosis of PMVT is difficult and readmission after colorectal surgery should prompt its consideration.
authors.affiliation: Department of Radiology, Mayo Clinic, 5777 East Mayo Boulevard, Phoenix, AZ, 85054, USA, Robinson.Kristin2@mayo.edu.
authors.forename: Kristin A
authors.initials: KA
authors.lastname: Robinson
authors.forename: Mark E
authors.initials: ME
authors.lastname: O'Donnell
authors.forename: David
authors.initials: D
authors.lastname: Pearson
authors.forename: J Scott
authors.initials: JS
authors.lastname: Kriegshauser
authors.forename: Melanie
authors.initials: M
authors.lastname: Odeleye
authors.forename: Kristen
authors.initials: K
authors.lastname: Kalkbrenner
authors.forename: Zachary
authors.initials: Z
authors.lastname: Bodnar
authors.forename: Tonia M
authors.initials: TM
authors.lastname: Young-Fadok
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003108:Colonic Diseases / Q000601:surgery*; D003107:Colorectal Surgery / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008642:Mesenteric Veins; D008875:Middle Aged; D011169:Portal Vein; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D012002:Rectal Diseases / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D020246:Venous Thrombosis / Q000453:epidemiology* / Q000209:etiology; D055815:Young Adult