Treatment strategies, bleeding, long-term recurrence and mortality in abdominal vein thrombosis : findings from the TROLL registry

Abstract

Background: Abdominal vein thrombosis (AVT) is an uncommon manifestation of venous thromboembolism (VTE). Data pertaining to management and the clinical course of AVT are limited.

Objectives: To investigate anticoagulant treatment strategies, bleeding complications, recurrence, and all-cause mortality among patients with AVT.

Methods: From January 2005 to December 2024, 241 patients with objectively confirmed isolated AVT were identified from The Venous Thrombosis Registry in ØstfOLd HospitaL (TROLL), Norway. Bleeding events were categorized as major bleeding (MB) or clinically relevant non-major bleeding (CRNMB) during anticoagulant treatment, and recurrent events were assessed after anticoagulant treatment discontinuation. Cumulative incidences of bleeding and recurrent events were estimated using the Fine-Gray subdistribution hazard model, accounting for the competing risk of death.

Results: Among 241 patients, 117 (48.6%) were women, median age was 61 (IQR: 49-71), and 86 (35.7%) had solid cancer. The portal vein was most frequently affected (n = 93, 38.6%), and 14 (5.8%) had liver cirrhosis. Overall, 237 (98.3%) received anticoagulant treatment; 150 (63.3%) with direct oral anticoagulants (DOACs) and 75 (31.7%) with low-molecular weight heparins (LMWHs). The 6-month cumulative incidence of MB was 3.4% (95% CI: 1.6-6.3) and of CRNMB 6.7% (95% CI: 3.8-10.3). Seven of 8 MB and eight of 15 CRNMB events occurred with LMWH treatment. The 5-year cumulative incidence of VTE recurrence after anticoagulant discontinuation was 9.6% (95% CI, 4.6-16.8).

Conclusion: Most patients were treated with DOACs. The incidence of MB and CRNMB was low. While the overall recurrence rate was also low, the upper-bound of CI indicates a non-negligible risk.