Experience with ultrasound-assisted catheter-directed thrombolysis in the treatment of patients with intermediate-high-risk pulmonary embolism

Aim. To compare the efficacy and safety of ultrasound-assisted catheter-directed thrombolysis (UACDT) using EkoSonic technology (EKOS Corporation, Bothell, Washington, USA) and a routine conservative approach with anticoagulant therapy (ACT) in patients with pulmonary embolism (PE) at intermediate-high risk for 30-day mortality. Material and methods. This single-center retrospective study included patients with confirmed intermediate-high-risk PE with thrombosis of the main or lobar branches of the pulmonary artery, no more than 14 days old. The patients were admitted to the cardiology intensive care units of the Almazov National Medical Research Center between January and December 2025. In accordance with the applied treatment strategy, patients were divided into 2 following groups: the UACDT group using EkoSonic technology (EKOS Corporation, Bothell, Washington, USA) and the ACT group. After 48 hours, the effectiveness of the treatment was assessed as follows: the incidence of decompensated hemodynamics episodes, the changes of right ventricle to left ventricle basal diameter ratio (RV/LV), decrease in the Qanadli score and the increase in residual peripheral flow according to computed tomography pulmonary angiography (CTPA), as well as the changes of right ventricular function echocardiographic parameters. Safety criteria included the incidence of minor and major bleeding. A telephone survey of patients was conducted one month after discharge to assess long-term outcomes. Results. The study included 41 patients, which were divided into 2 groups: ACT group — 21 patients; UACDT group — 20 patients. The endovascular treatment group showed a more pronounced reduction in right heart overload: Δ RV/LV according to CTPA was 0,40 [0,20; 0,70] in the UACDT group vs 0,03 [0,00; 0,40] in the ACT group (p=0,012). A reduction in the RV/LV ratio of more than 20% from baseline was achieved in 74% of cases in the UACDT group vs 30% of cases in the ACT group (p=0,010). According to echocardiography, there was a decrease in the right ventricular diameter by 11,0 [6,7; 13,8] mm in the UACDT group vs 6,0 [1,5; 8,5] mm in the ACT group (p=0,015), a decrease in the right atrial area by 5,20 [0,67; 6,25] cm 2 in the UACDT group vs 0,0 [-1,0; 2,8] cm 2 in the ACT group (p=0,050), a reduction in the inferior vena cava diameter by 2,0 [1,0; 6,0] mm in the UACDT group vs 0,0 [-0,5; 2,0] in the ACT group (p=0,040). In 2 cases (10%) in the UACDT group and in 6 cases (29%) in the conservative ACT group, hemodynamic destabilization was recorded (p=0,238), which served as the basis for "rescue" systemic thrombolytic therapy. Hemorrhagic events occurred in 5 cases (25,0%) in the UACDT group and in 2 cases (9,5%) in the ACT group (p=0,538). The incidence of minor and major bleeding was comparable between the groups as follows: 4 minor bleeding events in the UACDT group vs 2 in the ACT group (p=0,992) and 1 major bleeding event in the UACDT group vs 0 in the ACT group (p>0,999). Fatal outcomes were recorded in 1 case (5%) in the UACDT group and in 3 cases (14%) in the ACT group (p=0,606). Conclusion . There is a higher efficacy of UACDT in the form of a reduction in right ventricular overload in patients with intermediate-high-risk PE when compared with standard ACT with a comparable safety profile.