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Treatment options vary for massive, submassive PE
HOLLYWOOD, Fla. — The number of treatment options and lack of data raise questions about optimal treatment of patients with pulmonary embolism, particularly those with submassive PE, a speaker said at the International Symposium on Endovascular Therapy.
Risk stratification in PE, which is based on mortality rates for different types of patients, has become standard of care. Registries from the 1990s show that massive PE is associated with high mortality rates, ranging from 25% to 65%. Submassive PE, however, is more controversial, with prospective, randomized data that link submassive PE to a 3% mortality rate and registry data to a 9% to 10% mortality rate.
“Everybody with PE should be treated, but the real question here is: Beyond anticoagulation, what should we be doing with which patients?” Akhilesh K. Sista, MD, associate professor of medicine at New York University Langone School of Medicine, said during a presentation.
Treatment for massive PE
Both guideline recommendations and experience in clinical practice indicate that patients with massive PE must be treated, as they are the typically the sickest patients with the highest mortality risk.
“One of our large charges as interventionalists, surgeons and medical physicians is to rescue these patients from death, and each one of us plays a role in doing so,” Sista said.
He noted the treatment paradigm is based on three treatment options for patients with massive PE: systemic thrombolysis, catheter-directed therapy or surgical embolectomy.
“It’s likely that the patient presenting with massive PE will receive systemic thrombolysis if there are no contraindications to the treatment,” Sista said. “However, in certain scenarios in which there are contraindications, if the patient fails this treatment or if an alternative is preferred, then catheter-directed therapy or surgical embolectomy should be considered.”
In the 1990s, mortality rates for surgical embolectomy were about 50%, likely because cardiac surgeons were not training one another, Sista noted. A group from Massachusetts General Hospital, however, found that as they made embolectomies more commonplace and subsequently increased their experience with the procedure, mortality rates decreased significantly.
“It’s important for any group to have a cardiac surgeon on board who is aware of and up-to-date on these techniques because these are very powerful for the sickest patients,” Sista said. “Even though we have new technologies emerging, surgical embolectomy can’t be forgotten. Being able to open up a pulmonary artery and pull the embolus out is something we don’t necessarily have the capability of doing with other technologies at this time.”
In terms of catheter-directed therapies for massive PE, all therapies have been used, according to Sista.
“Any combination of the AngioVac (AngioDynamics), aspiration devices like the CAT 8 (Penumbra), clot maceration, the FlowRetriever (Inari) and infusion catheters have and can be used in patients to downgrade them to submassive PE,” he said. “It’s basically the kitchen sink. You have at your disposal any technique that will reduce that patient’s mortality risk.”
Treatment for submassive PE
The optimal treatment strategy for patients with submassive PE is slightly more complicated, Sista noted. For instance, although meta-analytic data have associated systemic thrombolysis with a reduction in mortality in patients with submassive PE, the treatment also increases risk for bleeding.
Catheter-directed therapy also appears to be beneficial, according to Sista. For example, in the ULTIMA trial, echocardiography 24 hours after the procedure was better with ultrasound-accelerated thrombolysis vs. heparin only. Similarly, in SEATTLE II, 48-hour CT showed reduced right ventricular to left ventricular ratio with delivery of tissue plasminogen activator with the EkoSonic Endovascular System (EKOS Corporation) plus heparin.
Nevertheless, studies have been small, Sista noted. SEATTLE II included 150 patients, the PERFECT registry included 100 patients and ULTIMA — the only randomized trial — included 59 patients, Sista said.
Data on the safety of catheter-directed therapies are also lacking, Sista noted. Although safety results have been encouraging so far, in SEATTLE II, the rate of major bleeding at 30 days was 11%, he said, meaning that these patients require transfusion. However, there were no intracranial hemorrhages. Therefore, many physicians may view it as a reasonable option for patients with submassive PE.
“From these initial studies as well as what I’ve seen in my clinical practice, catheter-directed thrombolysis seems efficacious, but we are lacking data on long-term clinical outcomes and short-term outcomes that would justify continuing this practice of using catheter-directed therapy in lieu of systemic thrombolysis,” he said.
Future directions
To help fill in the gaps in knowledge, Sista and colleagues are pursuing the PE-TRACT trial to evaluate clinically relevant short- and long-term outcomes through an NIH grant application. The PE-TRACT trial will have a randomized design and will compare catheter-directed therapy vs. no catheter-directed therapy in the setting of submassive PE. The investigators plan to enroll more than 400 patients at 30 to 50 sites. If funded, data are anticipated in 7 to 8 years.
“Massive PE patients should routinely be given some type of therapy, but what that is will never be figured out by randomized trials because it happens relatively rarely and something beyond anticoagulation needs to be done,” Sista said. “For submassive PE, the jury is still out.” – by Melissa Foster
Reference:
Sista A. Focused Symposium VI: Fundamentals of endovascular therapy. Presented at: International Symposium on Endovascular Therapy; Feb. 4-8, 2017; Hollywood, Fla.
Disclosure: Sista reports receiving research grants from Penumbra.