Timing and Location of Venous Thromboembolisms After Surgery for Inflammatory Bowel Disease.

Introduction: Patients with inflammatory bowel disease are reported to be at elevated risk for postoperative venous thromboembolism (VTE). The rate and location of these VTE complications is unclear.

Methods: Patients with ulcerative colitis (UC) or Crohn's disease (CD) undergoing intestinal operations between January 2006 and March 2021 were identified from the medical record at a single institution. The overall incidence of VTEs and their anatomic location were determined to 90 days postoperatively.

Results: In 2716 operations in patients with UC, VTE prevalence was 1.95% at 1-30 days, 0.74% at 31-60 days, and 0.48% at 90 days (P < 0.0001). Seventy two percent of VTEs within the first 30 days were in the portomesenteric system, and this remained the location for the majority of VTE events at 31-60 and 61-90 days postoperatively. In the first 30 days, proctectomies had the highest incidence of VTEs (2.5%) in patients with UC. In 2921 operations in patients with CD, VTE prevalence was 1.43%, 0.55%, and 0.41% at 1-30 days, 31-60 days, and 61-90 days, respectively (P < 0.0001). Portomesenteric VTEs accounted for 31% of all VTEs within 30 days postoperatively. In the first 30 days, total abdominal colectomies had the highest incidence of VTEs (2.5%) in patients with CD.

Conclusions: The majority of VTEs within 90 days of surgery for UC and Crohn's are diagnosed within the first 30 days. The risk of a VTE varies by the extent of the operation performed, with portomesenteric VTE representing a substantial proportion of events.