Portomesenteric venous thrombosis following major colon and rectal surgery: incidence and risk factors.

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).

Conclusion: 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.