Globally, pulmonary embolism or PE, a blood clot lodged in one of the pulmonary arteries in the lungs, is the third leading cause of cardiovascular-related deaths.Typically are treated with anticoagulants (commonly known as blood thinners) but of late the rise of the use of new interventional devices that remove or dissolve clots in the lungs has significantly increased in recent years.
However there is little data, particularly, as it pertains to the treatment of patients with “intermediate-risk PE”, that suggests these approaches are more safe and effective than the use of anticoagulation alone, according to a new scientific study from the American Heart Association (AHA) that was led by Penn Medicine.
“While the emergence of these interventional devices offers a new approach to treat pulmonary embolism, questions exist about when they should be administered and which patients would benefit the most. This statement aims to help stratify the risks associated with these approaches and guide clinical practice”
Dr Giri chaired the multi-disciplinary committee, comprised of 12 experts from nine different institutions, that published the research.
Pulmonary embolism, which is most often caused by blood clots that travel to the lungs from deep veins in the legs, affects as many as 12 million people each year globally. Historically, the majority of patients with PE have been treated with blood thinners, which help to prevent new clots from forming but do not eliminate existing clots. However, adverse outcomes in patients with intermediate and high-risk PE despite the use of anticoagulants have prompted the development of novel therapeutic approaches, including catheter-directed thrombolysis (dispensing “clot-busting” medication via a catheter that is threaded through the groin) and catheter-based embolectomy (removing the clot through a minimally invasive procedure). As of now, the US FDA has cleared two devices for the interventional treatment of PE, though many others are in the development pipeline.
However, there is limited evidence supporting the safety of the interventional therapies against more conservative approaches, partly because of the FDA’s decision to designate these devices as Class II (moderate risk), authors say.
According to the FDA, Class II devices include wheelchairs and some pregnancy tests, while Class III (high risk) devices ie those that present a potential unreasonable risk of illness or injury include recently evaluated cardiovascular devices, such as transcatheter heart valves and drug-coated balloons for peripheral artery disease. Unlike Class III devices, which require premarket approval from the FDA, the highest form of device regulation prior to device sales and marketing, Class II devices can receive clearance via the 510(k) clearance pathway. As a result, authors argue that high-level evidence demonstrating the safety and effectiveness of the devices, and justifying their use, will not be available before widespread marketing.
The researchers sought to raise awareness of the novel treatment approaches, advise of the potential benefits and risks of endovascular PE intervention and outline appropriate uses, including identifying which patients would derive the greatest benefit. While decisions to use interventional therapy are primarily driven by the severity of a patient’s condition and their risk of dying, authors note that it should also be influenced by patient-specific risk factors for comorbidities and bleeding. Finally, the team sought to lay out principles for research in the field, including appropriate study designs and patient criteria for needed future clinical trials.
The research team concluded that patients who are at the highest risk of dying of PE and lowest risk for bleeding benefit the most from more invasive therapies. Patients considered low-risk should be treated with anticoagulants alone. The team discouraged routine administration of interventional therapies to patients at intermediate risk, with patients in this group necessitating the most careful personalized assessment of risks and benefits of therapy.
“Considering the minimal short-term risk and low cost associated with anticoagulation alone, these interventional therapy devices must prove safety and effectiveness compared to anticoagulants in randomized clinical trials.As we move forward, it’s critical to design randomized trials that enable us to measure clinically meaningful differences in patient outcomes and quality of life.”commented Dr Giri.