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A Multitude of Options
Endovascular approaches for deep vein thrombosis, pulmonary embolism growing in use.
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The use of endovascular technologies and techniques for the treatment of patients with deep vein thrombosis or pulmonary embolism remains an emerging field, and there has been some debate among physicians regarding which patients would benefit from these technologies vs. surgery or medication.
Because these relatively new treatments are used by a wide range of different specialists and subspecialists — including ED physicians, critical care pulmonary physicians, cardiologists, radiologists, interventionalists, vascular physicians and cardiac surgeons — arriving at a consensus may be challenging.
“Pulmonary embolism (PE) is a new focus area for endovascular therapy, and we’re still in the process of trying to figure out who the best patients are to treat [with an endovascular approach] Clearly, not all patients need endovascular treatment,” James F. Benenati, MD, medical director of the peripheral vascular laboratory at Miami Cardiac and Vascular Institute and clinical associate professor of radiology at the University of South Florida College of Medicine, Tampa, told Cardiology Today’s Intervention.
Interest Continues to Increase
The interest in endovascular approaches to deep vein thrombosis (DVT) and PE has grown significantly in recent years, according to John Moriarty, MD, a specialist in vascular and interventional radiology at UCLA.
“Historically, medication has been the gold standard and, in many cases, the only treatment offered for these conditions,” Moriarty said. “Over the last 15 years — and particularly over the last 5 years — there has been a lot more interest, not only from the physician point of view, but also from patients with DVT themselves, about ways that will make them feel better quicker, get their life back on track in a more expedited way than medication alone, and may, in fact, give patients a better long-term outcome.”
This concept, in keeping with the emergence of more endovascular approaches to many conditions, has also given rise to new approaches to PE treatment, Moriarty said.
“Whether it’s devices or techniques for clot removal in the legs, in the belly, and within the heart and lungs with [PE], there is a huge level of interest at the moment,” he said. “There is a recognition that this is a huge problem throughout the country and that it’s probably undertreated. What the medical community is trying to do is find out who exactly should have any of the three options: medication, endovascular treatment or surgery.”
Factors in Decision Making
The decision regarding which treatment approach to take for a patient with DVT or PE often depends on the severity and location of the clot, the degree of disability to the patient and the risks of different treatment approaches.
“All patients with DVT should be on medication, unless they have a problem with bleeding or an allergy,” Moriarty said. “Then a decision needs to be made about whether they go on to more advanced treatment.”
Moriarty said he usually considers endovascular treatment in patients with significant disease burden or with clots in certain locations.
“The people who should get endovascular treatment are those who have a lot of disability; in other words, they have severe leg swelling or pain related to iliofemoral clots,” he said. “Patients who have an iliofemoral clot should at least be given the option of having an endovascular removal of that clot, and certainly they should be given the full discussion of the risks and benefits because there are many potential benefits they may accrue.”
When dealing with cases of PE, the treatment course is often guided by whether the PE is categorized as low risk, submassive or massive.
“With massive PE, something has to be done immediately. Those patients have a high mortality rate and so either systemic thrombolysis, catheter-directed lysis or mechanical devices need to be thought about,” Benenati said. “Submassive PE can be divided into stable or unstable, or high risk and intermediate risk.”
According to Keith M. Sterling, MD, chief of cardiovascular and interventional radiology at Inova Alexandria Hospital, Inova, Virginia, low-risk patients with PE are often treated successfully with anticoagulation.
“There is some controversy around treatment of patients with submassive or intermediate-risk PE,” Sterling told Cardiology Today’s Intervention. “These patients with right-heart strain may benefit from more aggressive treatment beyond anticoagulation, and there have been several trials that have been published demonstrating such positive outcomes. However, the jury is still out and published guidelines do not currently offer strong recommendations for this patient population.”
Sterling noted that investigations are ongoing to gain a better understanding of submassive PE.
“Research efforts are underway to look specifically at which therapeutic options are best for patients with submassive PE, as well as to risk-stratify this group of patients,” he said.
Testing, Patient History
Kenneth Rosenfield, MD, MHCDS, FACC, FSCAI, section head of vascular medicine and intervention at Massachusetts General Hospital and a founder of the institution’s Pulmonary Embolism Response Team (PERT), said when a case presents to the PERT team, initial testing is performed to acquire a good understanding of the nature of the clot and the patient’s history.
“We make sure CT is done to confirm the presence of a PE. We also make sure that the blood gas or oxygen saturation is done. We check the vital signs of the patient, the heart rate and BP in particular,” Rosenfield said. “We get a good history because that can actually drive the decision making. For example, if the patient has had an episode of syncope, that is almost by definition at least higher-risk submassive.”
Victor F. Tapson, MD, professor of medicine, pulmonary and critical care at Cedars-Sinai Medical Center, Los Angeles, told Cardiology Today’s Intervention that he also strongly considers these tests in his decision making.
“Vital signs are important. A heart rate of 70 bpm or 80 bpm is much different than a heart rate of 130 bpm,” he said. “I often risk-stratify someone differently and act more aggressively for a rapid heart rate. Oxygenation is important: How much oxygen does the patient require? The more oxygen they require, the sicker they are, and the more we need to consider being aggressive.”
The patient then typically undergoes blood work, including serum cardiac troponin T and N-terminal pro–B-type natriuretic peptide (NT-proBNP).
“Basically, if the troponin and BNP are elevated, they put you in a higher-risk group,” Benenati said. “In those patients, there is a mounting body of evidence that thrombolysis in these patients is beneficial. It’s not 100% proven, and there are still some conservative thought leaders that have very valid points as to why they’re uncertain of that. But we’re moving toward doing more and more of that because we think, especially in younger patients, we can help them and prevent longer-term problems.”
Use of Surgery
There continues to be disparity across institutions in the use of surgery for patients with DVT and PE.
“There is incredible variability around the country as to when patients get open-pulmonary thrombectomy. There are some institutions where it’s the first thing they go to for anybody with submassive or massive PE,” said Rosenfield, a member of the Cardiology Today’s Intervention Editorial Board and president of the Society for Cardiovascular Angiography and Interventions. “Most institutions are actually the other way around. They hardly ever do a pulmonary thrombectomy. We are somewhat in the middle. We try to use the team to decide if a patient will do better with an open surgical thrombectomy, then we go in that direction.”
Moriarty said his institution is generally conservative in the use of open surgery for clot removal.
“Rarely will surgery be used because it is invasive, it is painful, it is expensive,” he said. “The advanced treatment is almost always an endovascular clot removal or standing procedure.”
Rosenfield noted, however, that there are certain scenarios where surgery is considered.
“Things that might lead you to surgery are if there’s a clot in transit, for example,” he said. “If there’s a clot in the right atrium, we will think immediately about two different options. One is [the Vortex AngioVac device, AngioDynamics], because we’ve had great luck with [it] in that scenario, or open thrombectomy. Also, a massive PE, in the right setting, is best treated with open thrombectomy.”
Types of Endovascular Treatments
There two main approaches to endovascular treatment of DVT/PE, Moriarty told Cardiology Today’s Intervention. (See Sidebar for discussion of specific technologies.)
“There are two main ways of endovascularly removing a blood clot. The first is that you can dissolve it using catheter-directed thrombolysis (CDT),” he said. “The second way is to remove the clot with mechanical therapy by breaking it up or sucking it out.”
Although CDT has been shown to have distinct benefits in certain patients, it requires a longer hospital stay, according to Moriarty.
“The benefit of using CDT is that it dissolves all of the clot, and it gives you a relatively clean vein at the end of the procedure. We have data showing that, in the right patients, this is a very safe procedure,” he said. “The downside of it is that it takes time. Typically, it takes 24 hours, and patients must be admitted overnight.”
Conversely, mechanical therapy is associated with a shorter recovery time, but its benefits are not as proven.
“When you’re breaking up the clot or removing it straight away, the benefit is that it can be a day case. It can be performed in someone and they can go immediately home that afternoon,” Moriarty said. “They’re back sleeping in their own bed, they’re walking immediately. The chance of having any bleeding is lower, but we don’t have as much evidence for its success as we do with CDT.”
Challenges Remain
Rosenfield said the collaborative work by the PERT team has been instrumental in guiding decision making.
“In our team-based approach, we achieve consensus but we also lean on the guidelines and the evidence base that we have, which is already somewhat limited in terms of how people in different categories respond,” he said. “The lines are blurred, and it can sometimes be very challenging to ascertain whether the patient is going to do well with conservative therapy or more aggressive therapy. That’s why, in the absence of a very hard, firm evidence base, we love the consensus of the team.”
Benenati said it is important to remember that appropriate treatment of DVT and PE depends greatly on individual patient characteristics.
“There’s a whole gamut of what to do and when, and it really gets individualized to the patient — their risk factors, their age, how extensive their clot is, and how they’re doing clinically,” he said. — by Jennifer Byrne
- References:
- Piazza G, et al. JACC Cardiovasc Interv. 2015;doi:10.1016/j.jcin.2015.04.020.
- Kucher N, et al. Circulation. 2013;doi:10.1161/CIRCULATIONAHA.113.005544.
- For more information:
- James F. Benenati, MD, can be reached at Miami Cardiac and Vascular Institute, 8900 N. Kendall Drive, Miami, FL 33176; email: jamesb@baptisthealth.net.
- John Moriarty, MD, can be reached at David Geffen School of Medicine at UCLA, Peter V. Ueberroth Building, 19045 Le Conte Ave., Suite 3371, Los Angeles, CA 90093; email: tracypeterson@mednet.ucla.edu.
- Kenneth Rosenfield, MD, MHCDS, FACC, FSCAI, can be reached at Division of Cardiology, Massachusetts General Hospital, 55 Fruit St., Boston, MA 02114; email: krosenfield1@partners.org.
- Keith M. Sterling, MD, can be reached at Inova Alexandria Hospital, 4320 Seminary Road, Alexandria, VA 22304; email: keith.sterling@inova.org.
- Victor F. Tapson, MD, can be reached at 127 S. San Vincente Blvd., Suite A6100, Los Angeles, CA 90048; email: victor.tapson@cshs.org.
Disclosure: Benenati reports consulting for Penumbra and receiving royalties for the Indigo System. Moriarty reports serving as principal investigator for the Rapid Trial. Rosenfield reports receiving research funding from AngioDynamics, Boston Scientific and Inari. Sterling reports contracted research for Angiodynamics, EKOS/BTG and Penumbra, and consulting for Boston Scientific, EKOS/BTG and Penumbra. Tapson reports receiving institutional research grants from Bayer, BiO2, Daiichi Sankyo, EKOS/BTG, Inari, Janssen, and consulting for Bayer and Janssen.