Dual Therapy vs. Single Anticoagulation After Acute Deep Vein Thrombosis Iliac Stenting: A Doubly Robust Multicenter Study.

BackgroundThe optimal antithrombotic strategy after iliac vein stenting for acute iliofemoral deep vein thrombosis (IFDVT) remains uncertain. We compared dual antithrombotic therapy (DAT) with single anticoagulation (SAC) in patients with May-Thurner syndrome-related IFDVT.MethodsThis multicenter retrospective cohort included 450 patients undergoing successful iliac vein stenting between 2018 and 2022. At discharge, 186 received DAT and 264 received SAC. Inverse probability of treatment weighting, doubly robust estimation, and time-varying exposure modeling were used. The primary outcome was primary stent patency. Secondary outcomes included primary-assisted and secondary patency, chronic post-thrombotic symptoms requiring treatment, recurrent ipsilateral DVT, and bleeding.ResultsDuring a median follow-up of 46 months, DAT was associated with a lower risk of primary patency loss than SAC (sHR, 0.58; 95% CI, 0.41-0.82; p = 0.002); estimated 5-year primary patency was 81.8% versus 67.5%. Similar associations were observed for primary-assisted (sHR, 0.52; 95% CI, 0.35-0.78; p = 0.001) and secondary patency loss (sHR, 0.45; 95% CI, 0.28-0.71; p < 0.001). DAT was also associated with fewer chronic post-thrombotic symptoms requiring treatment (sHR, 0.61; p = 0.005) and recurrent DVT (sHR, 0.48; p = 0.019). Major bleeding did not differ significantly (HR, 1.28; p = 0.624), whereas clinically relevant non-major bleeding was more frequent with DAT (HR, 2.35; p < 0.001).ConclusionsDuring anticoagulant-treated follow-up, DAT exposure was associated with higher long-term stent patency and fewer clinically treated chronic post-thrombotic symptoms and recurrent DVT than SAC exposure, but with more clinically relevant non-major bleeding. The study does not determine the optimal duration of anticoagulation or the effectiveness of subsequent antiplatelet monotherapy.