Interventional Treatment of Deep Vein Thrombosis (DVT) at St. Charles Hospital
Cath Lab Digest Featured Venous Intervention Article
JASON P. JUNDT, MD, & WAYNE K. NELSON, MD
Can you tell us about your hospital?
Wayne K. Nelson, MD, FACS, RPVI: St. Charles Medical Center in Bend, Oregon is a regional hospital that provides care to central, eastern, and southern Oregon. There are several satellite hospitals as well. The hospital itself is about 280 beds and we have a state-ofthe-art hybrid operating room where we can perform both open and angiographic procedures. Bend Memorial Clinic’s vascular surgery department is the vascular service that serves the hospital system and all of the patients in the state east of the Cascade Mountains.
What types of patients do you see coming in with a deep vein thrombosis (DVT)?
Jason P. Jundt, MD: We see a wide range: young patients all the way up to very old patients. You can’t exclude people just on the basis of age. We see a range of demographics as well, including young females, those patients struggling with different forms of cancer, and other clinical presentations. DVT does not discriminate.
Why offer DVT patients an intervention?
Dr. Jundt: You can make a difference and improve quickly with durable results by intervening on a DVT patient, improving their quality of life dramatically. Patients would otherwise have to deal with a swollen leg and ulcers for the rest of their life, and potentially face the challenges of post thrombotic syndrome, which is an irreversible condition that permanently damages valve function. We are able to dramatically alter that course and it has become very attractive work as a result.
Dr. Nelson: We have an opportunity to make a meaningful difference, acutely, with relief of pain and swelling, restoration to ambulation, and occasionally, limb preservation. Aggressive treatment of DVT using devices can also minimize the risk of long-term complications.
What are your current treatment methods for DVT?
Dr. Nelson: Historically for DVT we have used catheter-based drip systems with tPA. The AngioJet ZelanteDVT thrombectomy catheter (Boston Scientific) is a recent addition to our device arsenal. The ZelanteDVT catheter is a larger mechanical thrombectomy device. It goes through an 8 French sheath and is able to remove a significant amount of clot, making it possible to treat patients in a single setting instead of multiple overnight stays in the ICU. With the use of this device, the patient goes to the hybrid operating room and is treated in one setting. We are able to clear the vast majority of the thrombus, if not all, and it eliminates the extended hospitalization that our patients used to require. Our other current options include catheter-directed thrombolytic (CDT) therapy to deliver tPA over the course of 12 or 24 hours, or sometimes longer. Some of these CDT catheters come with the addition of ultrasound propagation of the tPA.
Dr. Jundt: With the use of the ZelanteDVT catheter, I have seen a dramatic change from having to keep my patients in the intensive care unit (ICU) for several nights on a catheter-directed thrombolysis (CDT) drip, then watching them on the ward for a day or so, and then finally, sending them home. Now I can usually do the procedure in a single setting, transfer the patient to a lower level of care, and discharge most patients within 24 hours.
Is the ZelanteDVT only for use in acute patients?
Dr. Nelson: That is how we use it. The ZelanteDVT catheter can be used to provide an infusion of clot-busting drugs followed by thrombectomy, providing an increased ability to clear acute thrombus.
How do you decide whether a DVT patient receives medication or an intervention?
Dr. Jundt: I use ultrasound to analyze the lower extremity venous system and I will typically get a computed tomography (CT) venogram if I am considering intervention. I look for any other pathology in the abdomen, but also check to see if they have any signs of May-Thurner syndrome, cancer or other potential issues that could have caused the DVT. If the patient doesn’t have any contraindications and there is clot that extends up into the iliacs, then I am usually very aggressive and will do an intervention and utilize mechanical thrombectomy to remove the thrombus.
How often are you seeing acute vs chronic DVT?
Dr. Jundt: The chronic patients will show up at our clinic, typically months after the initial onset. Chronic patients require a different approach. Many have had inferior vena cava (IVC) filters placed previously and have veins that are either slightly recanalized or not recanalized at all. These patients get a CT venogram to evaluate their outflow and then we try to recanalize those veins. I usually am able to do that with just a Glidewire (Terumo) and a NaviCross catheter (Terumo). I will remove the IVC filters and may stent* through the previously occluded section, generally with very good success. People who have had swollen legs for a long time have experienced dramatic, durable results following this type of intervention. For acute patients, not all of them receive an intervention, but it is a significant portion (90%). Acute patients will come in from one of our referral centers (one of the surrounding hospitals that Dr. Nelson mentioned) or will come directly to our emergency room. Our volume varies. Some weeks we see several and then some weeks we see very few, but on average, we probably treat 4-5 acute patients per month. I do the same workup with acute patients, so they first get a CT venogram. In our practice, we are now able to treat DVT aggressively with interventional options. We are hoping to intervene earlier and that eventually this will lead to seeing fewer chronic patients.
Dr. Nelson: The whole idea of intervening up front is so you don’t end up having to treat chronic DVT patients. You always want to restore the patient, if possible, to their native situation with open thrombus-free veins and no stent. If we can do this, I think everybody would agree it is preferable. Now that we are being more aggressive with acute DVTs, hopefully we will be seeing less chronic DVT.
Can you talk more about how intervening with acute DVT might lead to a reduction in the number of chronic DVT patients?
Dr. Jundt: I just saw a patient today in follow-up where the initial treatment had been very aggressive. This young lady had May-Thurner syndrome and had come in with an extensive DVT, extending from her knee all the way up into her IVC. I used the ZelanteDVT catheter to remove the clot and stented her left iliac vein. Today was her 6-month follow-up and she is back to normal. Her DVT was the culmination of months of symptoms of venous outflow obstruction and caused symptoms including venous claudication. Seeing treatment success with these patients is really what makes you want to continue aggressively treating these types of conditions. My hope is, over time, we will see a resulting drop in our chronic patient population.
Before the use of devices for intervention in DVT, what was the standard of care?
Dr. Jundt: It was common to put someone on chronic anticoagulation, so they would get enoxaparin (Lovenox) and warfarin. Then, over the past several years, the novel anticoagulants like apixaban (Eliquis) and rivaroxaban (Xarelto) came into play, and are being commonly prescribed. Typically, you would put someone on anticoagulation with a compression stocking and then have them go home. More than one-third of patients with DVT will develop post thrombotic syndrome, and 5% to 10% of patients will develop severe post thrombotic syndrome, which may manifest as venous ulceration.1 Post thrombotic syndrome is what we are trying to avoid, because caring for ulcers and venous disease is such a burden to the patient and a burden to society.
What are the long-term symptoms of post thrombotic syndrome?
Dr. Jundt: Leg pain, leg swelling, ulcerations, and the development of wounds. Many of these symptoms are so disabling to patients that they can no longer work. There is no cure for post thrombotic syndrome; therefore, it is best to treat these patients early to remove the thrombus, which provides the best chance to avoid the development of post thrombotic syndrome.
How long has your program to intervene in DVT been active?
Dr. Nelson: It’s not a program per se, but an increasing awareness of the problem. We became more active in reaching out to all of the primary care providers and hospitalist teams about the need to treat some DVTs to prevent acute and long-term problems. We encourage them to call us about DVT patients so that we can offer treatment to them, provide a quick removal of thrombus, and prevent chronic problems.
Dr. Jundt: We also reached out to the emergency room physicians in order to increase their awareness and let them know that there are new options for the treatment of DVT. As a result of providing this education, our reach has blossomed to the point where we are treating DVT and now pulmonary emboli* as well. We are fairly aggressively treating patients that come in with systemic symptoms of what were DVTs and are now pulmonary emboli, with very good results.
What have been some of the barriers you have experienced in getting patients to come to you?
Dr. Nelson: Awareness, mainly. Once the primary care providers see what we can do, they start referring their DVT patients. The traditional algorithm for DVT, if it is not limb-threatening, is anticoagulation. Through education, we have been able to change that perception and educate physicians about the interventional alternatives to treat DVT.
How did you present this information to your community physicians?
Dr. Nelson: We are the vascular surgery service for the area and we have a closeknit medical community. Essentially all of the contact with other physicians is one-on-one. For us, education about DVT is involves getting the message out there to the emergency rooms, hospitalist teams, and the primary care physicians that for their DVT patients, especially iliofemoral DVTs or pulmonary emboli that are causing heart strain or other systemic symptoms, we have a better solution. We encouraged them to call us so we can talk to the patients, offer appropriate treatment options for them, and hopefully make their life better in the years to come. Once these providers started seeing the results of what we can accomplish, it snowballed and we have gained a lot of momentum based on impressive results.
Are there any ER protocols in place?
Dr. Nelson: The ER will call us for any DVT that manifests with pain and swelling, and for any iliofemoral DVT. We haven’t formalized a protocol yet, although it would be a good idea. Are you aware of any economic impact using an interventional approach for treating DVT? Dr. Nelson: Any time you can avoid an ICU stay or an extended hospitalization, you are going to be saving the hospital, insurance company, and the patient, money.
Dr. Jundt: There are studies showing that chronic venous hypertension from post thrombotic syndrome is a very expensive condition to treat. We have also found that the use of the ZelanteDVT catheter can shorten the patient’s hospital stay by up to two days. Based on my experience with the use of the ZelanteDVT catheter thus far, people are in the hospital for less than 24 hours. In the past, using a catheter-directed thrombolytic, patients would stay in the ICU for 24+ hours with the drip going, return to the hybrid room for another angiogram to see if things have cleared, maybe another catheter is used or more tPA is injected, and then the patient goes back to the ICU again or is discharged if nothing more can be done. Now we have the opportunity to get everything done in one trip to the hybrid operating room. After removing the thrombus, we send the patient to the ward rather than the ICU, and then send them home within 24 hours. In most cases, it is a significant cost savings to the patient and to the hospital.
How has hospital administration supported your efforts?
Dr. Nelson: They have been very supportive in getting us the devices we need to effectively treat our patients. In addition, two years ago, they built a phenomenal hybrid room for us to work in, where we can take care of patients in a way that is on par with anywhere in the country.
What is your DVT patient volume?
Dr. Jundt: I probably see at least 50 patients per month for some type of venous issue like DVT. It may be chronic venous hypertension, chronic venous ulcerations, or DVT. Perhaps 10-15% of the patients I see each month require an intervention. The others are treated medically. I am not as aggressive when patients have a tibial clot, for example, but anything above the knees, I am more aggressive. I tend to do an intervention if there is extensive clot burden above the knees.
Dr. Nelson: Of the patients we see with an iliofemoral DVT, who have acute pain and swelling, and no contraindications to the procedure, 100% will undergo some type of intervention to remove the clot burden and restore normal venous flow through the pelvis. After I explain the risks, benefits, and alternatives to intervention, I don’t think I have ever had a patient turn the therapy down.
How long is an intervention with the ZelanteDVT?
Dr. Jundt: It doesn’t usually take longer than an hour to treat an acute DVT.
Dr. Nelson: The ZelanteDVT catheter has a mode to deliver a clot busting medication directly into the thrombus. Part of the problem with leaving in an old-fashioned lytic catheter (CDT) is that the drug-clot interaction is only at the surface, but the ZelanteDVT catheter has what is called the Power Pulse mode, which will actually spray the drug into the acute clot. Dr. Jundt and I will always use the Power Pulse mode first in order to disperse drug throughout the clot. After a 20- to 30-minute dwell time, we remove the remaining clot using thrombectomy mode. I would say most of the procedures are completed in under an hour.
How quickly does the patient improve once you intervene?
Dr. Jundt: When removing the DVT using the AngioJet ZelanteDVT catheter, patients often see symptom relief within hours of treatment. Their pain begins to subside and swelling begins to disappear. We had a lady come in with phlegmasia cerulean dolens, a complete blockage of the venous outflow from the leg. Her leg was completely blue and painful with decreased pulses. Forty-five minutes later, after performing an intervention with the AngioJet ZelanteDVT catheter, her leg was normal color, normal size, and her pain had resolved. It can be quite dramatic.
Dr. Nelson: I will add, she had a limbthreatening condition. She would have lost her leg otherwise.
Any final thoughts?
Dr. Nelson: Using mechanical thrombectomy to treat DVT can make a dramatic difference in people’s lives. It adds to the number of procedures we offer that we feel very positive about doing and advocating for, because we always try to be our patients’ advocates. This is one procedure we feel strongly about, because it can make a big difference.
Dr. Jundt: For acute DVT patients, the sooner, the better, so we fit them in at any time. For the chronic patients, it is great to be able to get them in on a lab day, and usually the procedure doesn’t take very long and makes a huge difference. That’s what we are looking for — the ability to make a difference in these people’s lives. Maybe they don’t realize it, but the impact is actually most significant 5-10 years down the road when these patients are able to avoid experiencing post thrombotic syndrome.
ZelanteDVT Thrombectomy Set
CAUTION: Federal law (USA) restricts this device to sale by or on the order of a physician. Rx only. Prior to use, please see the complete “Instructions for Use” for more information on Indications, Contraindications, Warnings, Precautions, Adverse Events, and Operator’s Instructions.
INDICATIONS AND USAGE
The ZelanteDVT Thrombectomy Set is intended for use with the AngioJet Ultra Console to break apart and remove thrombus, including deep vein thrombus (DVT), from: • Iliofemoral and lower extremity veins ≥ 6.0 mm in diameter and • Upper extremity peripheral veins ≥ 6.0 mm in diameter.
The ZelanteDVT Thrombectomy Set is also intended for use with the AngioJet Ultra Power Pulse® technique for the controlled and selective infusion of physician specified fluids, including thrombolytic agents, into the peripheral vascular system.
Do not use the catheter in patients: • Who are contraindicated for endovascular procedures • Who cannot tolerate contrast media • In whom the lesion cannot be accessed with the guidewire
WARNINGS and PRECAUTIONS
The ZelanteDVT Thrombectomy Set has not been evaluated for treatment of pulmonary embolism. There are reports of serious adverse events, including death, associated with cases where other thrombectomy catheters were used during treatment of pulmonary embolism.
• The ZelanteDVT Thrombectomy Set has not been evaluated for use in the carotid or cerebral vasculature. • The ZelanteDVT Thrombectomy Set has not been evaluated for use in the coronary vasculature. • Operation of the catheter may cause embolization of some thrombus and/or thrombotic particulate debris. Debris embolization may cause distal vessel occlusion, which may further result in hypoperfusion or tissue necrosis. • Cardiac arrhythmias during catheter operation have been reported in a small number of patients. Cardiac rhythm should be monitored during catheter use and appropriate management, such as temporary pacing, be employed, if needed. • Use of the catheter may cause a vessel dissection or perforation. • Do not use the AngioJet Ultra System in patients who have a non-healed injury due to recent mechanical intervention, in the vessel to be treated, to avoid further injury, dissection, or hemorrhage. • Do not use the ZelanteDVT Thrombectomy Set in vessels smaller than minimum vessel diameter as listed in Table 1 of the IFU; such use may increase risk of vessel injury. • Systemic heparinization is advisable to avoid pericatheterization thrombus and acute rethrombosis. This is in addition to the heparin added to the saline supply bag. Physician discretion with regard to the use of heparin is advised. • Do not pull the catheter against abnormal resistance. If increased resistance is felt when removing the catheter, remove the catheter together with the sheath as a unit to prevent possible tip separation. • If resistance is felt during the advancement of the ZelanteDVT Thrombectomy Set to lesion site, do not force or torque the catheter excessively as this may result in deformation of tip components and thereby degrade catheter performance. • The potential for pulmonary thromboembolism should be carefully considered when the ZelanteDVT Thrombectomy Set is used to break up and remove peripheral venous thrombus
Potential adverse events which may be associated with use of the AngioJet Ultra Thrombectomy System are similar to those associated with other interventional procedures and include, but are not limited to:
• abrupt closure of treated vessel • acute myocardial infarction • acute renal failure • bleeding from access site • cerebrovascular accident • death • dissection • embolization, proximal or distal • hematoma •hemolysis • hemorrhage, requiring transfusion • hypotension/hypertension • infection at the access site • pain • pancreatitis • perforation • pseudoaneurysm • reactions to contrast medium • thrombosis/occlusion • total occlusion of treated vessel • vascular aneurysm • vascular spasm • vessel wall or valve damage
AngioJet, ZelanteDVT, and Power Pulse are registered or unregistered trademarks of Boston Scientific Corporation or its affiliates. All other trademarks are property of their respective owners.
1. Kahn SR. How I treat postthrombotic syndrome. Blood. 2009 Nov 19; 114(21): 4624-4631. doi: 10.1182/ blood-2009-07-199174.