Portomesenteric Venous Thrombosis in Patients Undergoing Surgery for Medically Refractory Ulcerative Colitis.

Background: Portomesenteric venous thrombosis (PMVT) is an under-recognized complication of colorectal surgery. The aim of this study was to describe the rate and risk factors for PMVT in patients undergoing surgery for medically refractory ulcerative colitis (UC).
Methods: A retrospective review of medically refractory UC patients who underwent surgery between January 2010 and December 2016 at a single tertiary care center was conducted. PMVT was defined as thrombus within the portal, splenic, superior, or inferior mesenteric vein on postoperative abdominal computed tomography scans. Factors associated with PMVT on univariable analysis were tested in multivariable analysis. Clinical relevance of risk factors was examined with receiver operating characteristic curves and Kaplan-Meier curves.
Results: A total of 434 patients were identified. Postoperative venous thromboembolism (VTE) prophylaxis was administered to 428 (98.5%) inpatients for a mean duration of 7.7 ± 0.17 days. PMVT developed in 36 (8.3%) patients a mean interval of 55.3 ± 10.8 days after index surgery. The majority of PMVT occurred after subtotal colectomy, and the most common initial symptom was abdominal pain. Preoperative C-reactive protein (CRP) was associated with PMVT (odds ratio, 1.01; 95% confidence interval, 1.00-1.02; P = 0.01), and the optimal predictive CRP threshold was 45 mg/L. The rate of PMVT development was greater for patients with CRP >45 mg/L (P = 0.01).
Conclusions: PMVT can present as abdominal pain and occur multiple weeks after discharge. Further studies are needed to identify the appropriate postoperative outpatient thrombosis prophylaxis regimen for at-risk patients.
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