How to Assess and Treat the DVT Patient

[Chris Beck]
Can you kind of describe the ideal patient who you think is going to benefit from DVT treatment? Can you kind of describe what that patient might look like?

[Steven Abramowitz]
The ideal patient is the young, healthy individual, male or female, who probably is hypercoagulable and had their first episode of deep vein thrombosis, usually surrounding a flight or sometimes an anatomic compression like a May-Thurner lesion. They are mobile, healthy in shape, no contraindications to anticoagulation. Usually, they're young in their 20s or 30s. With a proximal DVT, treating them is going to give them symptomatic relief and also prevent post-thrombotic syndrome down the line, especially because they're at high risk for having a recurrent thromboembolic event as a result of their hypercoagulable state.

[Chris Beck]
What would be the ideal time frame in which you would be able to see this patient and intervene?

[Steven Abramowitz]
As soon as possible. In reality, usually by the time these patients end up in the emergency room, when they are swollen and heavy, symptomatic for a few days. It's very rare that someone wakes up that morning and drags himself to the doctor's office. Most of the time when you're interacting with patients, even if they've only been symptomatic for a few days, the clot we're dealing with is probably a week to a week and a half old.

[Chris Beck]
Can you describe someone who's maybe a more typical patient that you're used to seeing in your clinic?

[David Dexter]
The more regular people are those that had an IVC filter placed some number of years ago, and it was forgotten about or it was permanent. We have a catastrophe with the number of permanent TRAPEASE filters that got placed and left in very young otherwise healthy, usually women for some reason that have now gone on thrombosis through IVC both iliac veins.

[Steven Abramowitz]
Taking a step back again from that ideal patient and really focusing on that 50% of the patient population with something else going on in their health that caused them to develop a clot—for the most part, we're seeing oncology patients coming in with lower extremity DVT. They either have or do not have metastatic disease, and those patients are really not good lytic candidates. Otherwise, we're seeing patients who are already hospitalized, who either had prolonged hospitalizations or had orthopedic surgery with proximal DVT. And then the last are those people coming into the ER with some hypercoagulable state or something with their first or other recurrent DVT state.

[David Dexter]
There are many patients who had a prior DVT, and they didn't know where to get help from. They got put on anticoagulation for three months, six months, depending on what protocol they were following, and they were out in the wilderness. They were doing okay, and they didn't realize that the heavy, achy, throbbing leg they were dealing with for ages is treatable. They also didn't know that they could have a new acute event on top of their chronic obstruction.

[Steven Abramowitz]
There's a very big patient population in most communities and most major metropolitan areas of untreated, post-traumatic patients who are suffering from the sequelae of acute DVT long term. Post-thrombotic syndrome is the long-term impact on the vein, and its ability to carry blood in a low pressure and low flow state. Once the vein is scarred and has changed that compliance from the inflammatory process that is instigated to deal with deep vein thrombosis, and you're behind the eight ball. We really need to target those patients that present with acute DVT in the emergency room, in urgent care centers, in the outpatient, or inpatient setting. There's a huge opportunity for us to prevent that disease process from progressing by intervening on the acute stage, which is deep vein thrombosis.

[David Dexter]
Steve said it exactly right. The right patients don't come at the right time and the wrong patients come at the wrong time, really. When I started in practice, the first system wide initiative that I took on was to start an algorithm and a treatment paradigm for acute DVT. Our acute DVT pathway starts when any patient shows up either to one of our family practice doctors in our multi-specialty group, one of our urgent cares, or one of our ERs. We've integrated this algorithm into the electronic medical record. So, once patients are divided up into high risk or low risk categories, we determine who should go home, who should be admitted to the hospital, and who should see an interventionalist early.

[David Dexter]
For the most part, DVT intervention can be done awake with good moderate sedation in the prone position in the lab. I very rarely find the need to do a DVT case in the hybrid OR, unless I'm using the AngioVac, where I'm trying to really move large burden clot out of the IVC, both iliacs, both femoral. Those people I do under general anesthesia in the hybrid OR with perfusion, but pretty much everybody else is in the lab.

[Chris Beck]
Can you talk about the procedure components, where you treat these patients and maybe potential access sites, and how you're going to initiate the procedure?

[Steven Abramowitz]
I think that there's a lot of debate as to access site selection. One of the key things is whether or not you fall into the camp that every single inflow vessel needs to be treated or that you need to treat the major inflow vessel (the femoral-popliteal segment to the common term role or the external iliac). For the most part, I would recommend your access site being either the popliteal vein or the small saphenous vein. If you buy into treating the tibial inflow vessels, I would use the posterior tibial vein as an access site because really, if you're doing catheter-directed thrombolysis, that's going to give you the maximum kind of bang for your buck in terms of clot exposure to the TPA. I would really focus in on the popliteal vein or the posterior tibial vein if you're doing catheter-directed thrombolysis. Most of the mechanical thrombectomy devices aren't going to be supported by tibial veins so if you're really focusing on mechanical thrombectomy, such as using the MRI device or Penumbra device, then you can focus more on the internal jugular or the popliteal. If you enter into the common femoral vein, you really are running a risk of missing a lot of that proximal DVT.

[David Dexter]
I think again, Steven said it right. You want to expose as much of the clot to therapy as you possibly can.

[Chris Beck]
What percentage of your cases are you using IVUS?

[Steven Abramowitz]
100%. It's really surprising the number of cases you do where you do a CT venogram and you think "Wow, that vein looks great." You throw an intravascular ultrasound catheter in there, and you say "Geez, that's got 30% circumferential or partial thrombosis of the vein." So, I think that without intravascular ultrasound, you are really under assessing the extent of disease and the potential anatomic compressive lesion that may be leading to the disease.

[David Dexter]
The imaging provided by intravascular ultrasound can tell us what the clot morphology looks like. It could show us scarring on the wall, it can show us external compression. You don't know what you're not treating until you look. If you're not operating with IVUS when you're doing a DVT case, you're breaching the standard of care I would think in 2020.