Clinical Significance of Early Computed Tomography Scan on Thrombus Regression Rate in Acute Pulmonary Embolism: Insights from the SAKURA PE/DVT REGISTRY

Aims: Direct oral anticoagulants (DOACs) are used to treat venous thromboembolism (VTE). However, their impact on thrombus regression and the clinical outcomes after 2-week post-therapy computed tomography (CT) monitoring remains unexplored. This study aimed to elucidate the characteristics of patients with VTE treated with individual DOACs, assess the incidence of clinical events, and evaluate their impact on pulmonary artery thrombus regression. Methods: This prospective, multicenter study in Japan included 175 patients with VTE treated with rivaroxaban, apixaban, and edoxaban. We employed 2-week post-therapy CT monitoring to compare thrombus regression rates, patient backgrounds, and clinical outcomes. Results: Rivaroxaban users had higher body weight, hemoglobin levels, pulmonary embolism prevalence, and larger thrombus volume, but a lower prevalence of active cancer than apixaban and edoxaban users. The median thrombus regression rate after approximately 2 weeks of treatment was 89.9%, with no significant differences between the DOACs. During the 13.5-month follow-up, the recurrence or aggravation of symptomatic VTE did not differ significantly among the groups; however, the apixaban group exhibited a slightly higher major bleeding rate. Among the 95 patients receiving rivaroxaban intensive therapy, 34 (35.8%) experienced early termination due to sufficient thrombus resolution within 2 weeks compared to the standard duration group. This did not increase VTE recurrence, aggravation, or mortality. Conclusions: Substantial thrombus regression and a low incidence of VTE and bleeding support the effectiveness of DOACs. Terminating intensive therapy in one-third of the rivaroxaban group after 2-week CT monitoring did not increase the occurrence of VTE events, thereby suggesting suitability for patients at a high risk of bleeding. Clinical Trial Registration Number: SAKURA PE/DVT REGISTRY (UMIN Clinical Trials Registry: UMIN000047671, Registration Date: May 6, 2022)