VIENNA — The optimal course of treatment when managing acute, high-risk pulmonary embolism (PE) remains a contentious topic among respiratory specialists.
Systemic thrombolysis, specifically using recombinant tissue plasminogen activator (rtPA), is the current gold standard treatment for high-risk PE. However, the real-world application is less straightforward due to patient complexities.
Here at the European Respiratory Society (ERS) 2024 Congress, respiratory specialists presented contrasting viewpoints and the latest evidence on each side of the issue to provide a comprehensive framework for navigating the complex decision-making process required for effective treatment.
“High-risk PE is a mechanical problem and thus needs a mechanical solution,” said Parth M. Rali, MD, an associate professor in thoracic medicine and surgery at the Lewis Katz School of Medicine at Temple University, Philadelphia.
“The marketing on some of the mechanical techniques is very impressive,” said Olivier Sanchez, MD, a pulmonologist in the Department of Pneumology and Intensive Care at the Georges Pompidou European Hospital in France. “But what is the evidence of such treatment in the setting of pulmonary embolism?”
The Case Against rtPA as the Standard of Care
High-risk PE typically involves hemodynamically unstable patients presenting with conditions such as low blood pressure, cardiac arrest, or the need for mechanical circulatory support. There is a spectrum of severity within high-risk PE, making it a complex condition to manage, especially since many patients have comorbidities like anemia or active cancer, complicating treatment. “It’s a very dynamic and fluid condition, and we can’t take for granted that rtPA is a standard of care,” Dr. Rali said.
Alternative treatments such as catheter-directed therapies, extracorporeal membrane oxygenation (ECMO), and surgical embolectomy are emerging as promising options, especially for patients who do not respond to or cannot receive rtPA. Mechanical treatments offer benefits in reducing clot burden and stabilizing patients, but they come with their own challenges.
ECMO can stabilize patients who are in shock or cardiac arrest, buying time for the clot to resolve or for further interventions like surgery or catheter-based treatments, said Dr. Rali. However, it is an invasive procedure requiring cannulation of large blood vessels, often involving significant resources and expertise.
Catheter-directed thrombolysis is a minimally invasive technique where a catheter is inserted directly into the pulmonary artery to deliver thrombolytic drugs at lower doses. This method allows for more targeted treatment of the clot, reducing the risk for systemic bleeding that comes with higher doses of thrombolytic agents used in systemic therapy, Dr. Rali explained.
Dr. Rali reported results from the FLAME study, which investigated the effectiveness of FlowTriever mechanical thrombectomy compared with conventional therapies for high-risk PE. This prospective, multicenter observational study enrolled 53 patients in the FlowTriever arm and 61 in the context arm, which included patients treated with systemic thrombolysis or anticoagulation. The primary endpoint, a composite of adverse in-hospital outcomes, was reached in 17% of FlowTriever patients, significantly lower than the 32% performance goal and the 63.9% rate in the context arm. In-hospital mortality was dramatically lower in the FlowTriever arm (1.9%) compared to the context arm (29.5%).
When catheter-based treatment fails, surgical pulmonary embolectomy is a last-resort option. “Only a minority of the high-risk PE [patients] would qualify for rtPA without harmful side effects,” Dr. Rali concluded. “So think wise before you pull your trigger.”