Ultrasound-assisted catheter-directed thrombolysis for pulmonary embolism: current evidence, limitations, and future directions.

内容摘要

Pulmonary embolism (PE) is the third leading cause of cardiovascular death globally and continues to carry high rates of morbdity and mortality despite advances in therapy. While risk stratification helps guide treatment for both low- and high-risk patients, optimal management of intermediate-risk PE remains unclear. Although contemporary AHA/ACC guidelines introduce more granular clinical categories to better define risk and guide treatment selection within this heterogeneous population, uncertainty persists. Systemic fibrinolysis poses bleeding risks, whereas anticoagulation alone may not be sufficient to prevent clinical deterioration. Catheter-based approaches, such as ultrasound-assisted catheter-directed thrombolysis (UACDT), have therefore emerged as potential options that deliver lower-dose fibrinolytics directly into the pulmonary arteries. However, much of the existing literature combines UACDT with other catheter-based interventions, making it difficult to isolate its specific contribution. The data are also heterogeneous, limiting cross-study comparisons. This review summarizes the current evidence, influential clinical trials, and ongoing studies on UACDT, with a focus on its therapeutic potential, safety considerations, limitations, and evolving role in the management of intermediate-risk PE. A literature search was conducted using PubMed, Embase, and ClinicalTrials.gov from inception through early 2026, with supplementary searches performed using Google Scholar. A pulmonary embolism occurs when a blood clot blocks the vessels between the heart and the lungs, preventing the heart from pumping blood to the lungs and the lungs from receiving blood from the heart. There is a wide range of severity. Some patients are very stable and can be treated with standard blood-thinning medications alone; these patients are low risk. Other patients are high risk; they are extremely sick and require urgent therapies to remove the clot from vessels, relieve stress on the heart, and restore oxygen to the lungs. The patients in between are intermediate-risk, and their treatment is less straightforward. For these patients, blood thinners alone may not be enough, but the stronger therapies can make them bleed extensively (sometimes into their brain).One option for this group is ultrasound-assisted catheter-directed thrombolysis, or UACDT. An experienced doctor places a small tube into the lung vessels to deliver medication that breaks up the clot; the device also uses ultrasound waves (“vibrations”) to disrupt the links holding the clot together. The idea is to reduce strain on the heart and repair blood flow while using less medication that causes bleeding.The evidence for this therapy is inconsistent and can be difficult to apply in real-world settings. In this paper, we evaluated the research on UACDT. We found that UACDT can work for some patients but is not necessarily better than other treatments. More research is needed to better clarify the outcomes of this treatment.