Pulmonary artery fresh floating thrombus in patients with chronic thromboembolic pulmonary hypertension on low-dose direct oral anticoagulants: A single-center angiographic observational study.

Direct oral anticoagulants (DOACs) are widely used in chronic thromboembolic pulmonary hypertension (CTEPH); however, the safety and efficacy of reduced-dose regimens remain unclear. We retrospectively analyzed 721 follow-up selective pulmonary angiograms from 239 patients who completed balloon pulmonary angioplasty and received long-term anticoagulation with low-dose DOACs, standard-dose DOACs, or vitamin K antagonists (VKAs). Baseline characteristics, follow-up outcomes, and the incidence of pulmonary artery fresh floating thrombi were compared using the Kruskal-Wallis and Fisher's exact tests. Patients on low-dose DOACs were older, had lower body weights and more frequent renal impairment. Fresh thrombi were identified in 22 cases (3.1%), with a higher incidence in the low-dose DOAC (11.0%) group versus standard-dose (2.1%, p = 0.044) and VKAs (2.5%, p = 0.018). Hemodynamic improvements were comparable across groups. Low-dose DOACs were associated with a higher thrombus rate, suggesting potential under-anticoagulation. These findings highlight the need for CTEPH-specific anticoagulation strategies to balance thrombotic and bleeding risks.