Kendal Williams, MD (Host): Welcome everyone to the Penn Primary Care podcast. I'm your host, Dr. Kendal Williams. So one of the most interesting areas in medicine over the last 10, 15 years has been the ability to thread catheters into arteries and veins and solve problems. And there's no one better at Penn that does that than Dr. Rob Fenning, who is a Cardiologist here, Associate Professor of Clinical Medicine, and in the division of Cardiology. And I asked Rob to come on to talk about the variety of procedures that he actually does. He does both venous procedures for DVT and PE, also dealing with superficial venous varicosities, some work with venous stasis management, but also does peripheral arterial disease in addition, to the standard work of interventional cardiologists do for the coronary arteries. So there's nobody who knows better about veins and arteries than Rob Fenning. So Rob, thanks for coming.

Robert Fenning, MD: Oh, thanks for having me, Kendal. I appreciate it.

Host: So, Rob, I know you're more or less a Penn lifer. I think you went to Cornell undergrad, but you've been here ever since, right?

Robert Fenning, MD: Yeah, it's been a long time, since 2004 is when I started med school at Penn. And uh, I think maybe either as a med student or an intern, you were my attending, I think on one of those.

Host: I think you're right as well. I know, that's what happens if you're at this long enough, your med students end up becoming your consultants. But you've taken an interesting path, and I want to highlight this. I think a lot of cardiologists who do interventional fellowship focus on the coronary arteries and do exclusively that. To me, it seems you're unique because you have really also gotten involved in peripheral catheterization, like veins and arteries and everything else. I suppose that is different, right?

Robert Fenning, MD: Yeah, it is actually, especially coming from Penn and HUP, a lot of the interventionalists will do structural and coronary work. So structural work would be like the interventional valve stuff like TAVRs and mitral valve interventions. But I had, like very early on, had an interest in vascular medicine and vascular intervention, so I sought out this like less common pathway. But I really enjoy it.

Host: Yeah. And it's immensely interesting. And you and I have shared patients in the past. You've educated me about, a lot of things related to these procedures and, that's why I really wanted to have you on because even though I've been sort of out of the daily Presbyterian environment where you work, for the last five years, there was a lot going on back then and now I think there's even further advances and some advancement in the studies in terms of the research of what we know works, right?

Robert Fenning, MD: Yeah, for sure. One thing I'll say is that, we don't get a lot of vascular training during residency, internal medicine. So a lot of this stuff I learned even during the later years of my interventional years. And, I'm happy to share it with you. But I find it to be a field that's just not a lot of internists know that much about, because we don't get a lot of exposure to it.

Host: I, think that's absolutely right, and, so I'm glad you're here. So, I want to actually start with a case, and it was a case that I talked to you about, probably about five years ago that I managed on the Presby in-patient service. But it brings up a lot of these issues, particularly in relation to DVT and PE.

And, I cared for a young woman who had presented to her primary care, with a DVT, basically with swelling in her leg, ultimately determined a fairly large DVT in her leg, Iliofemoral. She was placed on a DOAC. She kind of took it intermittently. She didn't consistently take it.

And then a couple weeks later came back in with shortness of breath and chest discomfort and had a large PE. And they dopplered her legs and she still had clot in her legs, but less than was there previously. Because some of it was in her lungs. And she was admitted to my service. She at that point had residual clot in her leg, a fairly extensive amount and some discomfort from that.

But also now this large PE with some right heart strain, but not hypotensive. So she, what we'll go over in a minute, but she was basically an intermediate risk patient. So this patient educated me a lot. And let's start with just DVT in general and then I want to get back to managing her PE.

So we're diagnosing a lot of DVTs in our practices. It's very common. And, when should we be thinking about referring patients acutely for intervascular intervention for DVT alone?

Robert Fenning, MD: Yeah, it's a good question Kendal. So, lower extremity DVTs can cause long-term consequences. And the worst thing is like post thrombotic syndrome, which is very chronic, severe leg swelling. In the worst case scenarios, patients can have venous ulcers from venous hypertension.

 And so our goal is to treat the patient's acute swelling and pain, but also try to prevent like long-term, severe post-thrombotic syndrome. And over the years there have been, there's a lot of new technologies in treating lower extremity DVTs, interventionally. And each time, like these new catheters come out, usually there's like a trial, where the company shows or whether it's company driven or an NIH driven trial.

And, the outcomes of these trials are always to try to prevent post-thrombotic syndrome. And there have been some positive trials. But it's a hard thing to prevent. And a lot of the trials show, the largest trial is an NIH sponsored trial called the ATTRACT trial.

And their endpoint unfortunately was yes, no, does the patient have post thrombotic syndrome? And they actually didn't meet their like endpoint, but they actually showed that the secondary endpoints of decreasing the severity of post-thrombotic syndrome, was significantly reduced with DVT interventions.

And that is a positive secondary endpoint when your primary endpoint didn't get hit in a randomized control trial. So it's more provocative or, it's not a definitive positive trial. But in any event, we know that the more proximal a DVT is, the larger the DVT, the more proximal the DVT, the more likely the patient will have severe long-term post thrombotic syndrome.

And so, when I am called or I read a study on a patient with a DVT, I'm looking to see if their common femoral vein is totally occluded. Now I say the common femoral vein because the routine ultrasound technician is going to look from the common femoral vein down distally to the foot when they ultrasound the veins.

And they don't routinely look in the iliac veins because the abdomen, it's hard to visualize those veins. But you can be assured that if the common femoral vein is totally occluded, that the thrombus is going to extend into the iliac vein. So I really want to treat patients with occluded iliac veins.

And if the common femoral vein is occluded, then the iliacs are occluded. And so that subgroup of patients have, will, are the ones who will benefit most from a DVT intervention, such that it's really the thing that I tell, I give talks to the ER and talk to doctors who ask me when should they refer these patients to me.

And it's, if their common femoral vein is totally occluded. DVT that's lower down in the thigh, those patients, there hasn't been as strong a signal that doing procedures on those patients will really help them.

Host: And so, before we talk about the procedures, I actually want to talk about clots themselves because, we learn about these things. We're always treating them medically, sort of, you know, on a system level, right? So on a body system level, but not, to the specific clots. So we don't really learn a lot about clots.

So I'm assuming people develop post-thrombotic syndrome because the clot itself does destruction to the valves, right? So they're effectively check valves, and if you destroy those, they get floppy. And so patients are going to develop post-thrombotic syndrome on that basis. Is that correct?

Robert Fenning, MD: Yeah, I mean, listen, we don't really know exactly, but there's probably multiple factors. And one significant factor is whether or not the blood clot is damaging those valves because, the other factor is whether or not the veins ever open back up with anticoagulation. So there's this like open vein hypothesis, which is, which assumes that if you can just get the clot out, they won't get post thrombotic syndrome because the veins are open. That's this open vein hypothesis.

But we know that patients can still develop post-thrombotic syndrome even though you clean or all the clot dissolves, and it's because of what you said. It's more complicated. There's valves in there that can get destroyed despite the clot going away. Whether that's because you started a DOAC and the clot dissolved, or because you did a procedure and removed that clot. You can get all the clot out and you can get an ultrasound a month later to show that there's no residual DVT and those patients can still get post-thrombotic syndrome.

Host: The natural history of a clot, even if we did nothing, right, even if we didn't treat with an anticoagulant; is to eventually be fully resolved, right?

Robert Fenning, MD: Ideally. And there's data that if there's a patient in your clinic and they have a blood clot below the knee, so a distal DVT, whether it's a tibial vein, like a posterior tibial vein or even one of the intramuscular veins, like the soleal vein, there's data that you can follow those patients and not anticoagulate them and ultrasound them a week later and a week after that.

And you'll find that a lot of these patients will resolve their own DVTs or they at least won't.propagate proximally. And so if you're seeing an elderly patient with a distal DVT, you're worried about putting them on a blood thinner. It's totally legit, and there's data for following them conservatively.

But you have to repeat ultrasounds two weeks in a row to make sure that the DVT doesn't propagate proximally. And you'll find that a lot of these resolve on their own, but that's ideal. And the patients who are getting DVTs, they might be hypercoagulable or immobile, and so it doesn't always work, so you can't just rely on the body's own ability to dissolve a clot. And that's why we treat them.

Host: Now this is, from my understanding, maybe going back decades, but, I always had the impression, probably from something I read that the anticoagulants we use, even heparin, Coumadin in the back in the day, and now DOACs actually primarily act to not all allow, help the body to not so much to dissolve the clot, but to keep the body from forming new clots, on that existing clot.

And that the body itself will clear the existing clot, because you're not forming new clot, you're not propagating it at all. That may be a semantic difference, but that's always the way I understood it.

Robert Fenning, MD: Totally. That is like the medical student teaching when you're like studying the pathophysiology of the thrombotic cascades. But I'll tell you that I've done many procedures on patients where the day that I do the consult on them, there's blood clot that's extending totally down all the way down to their ankles.

And by the time I bring them in the next day to do my procedure, if it's a day later that, it's not uncommon for me to see a lot of that clot resolve, within 24 hours. But anyway, I mean, I guess it doesn't prove the point, but when you put a patient on a blood thinner, they could like quickly and very massively improve their thrombotic burden.

Host: You're describing patients even within hours, but within a few days. Yeah.

Robert Fenning, MD: The way that I do these DVT interventions is I put them on their belly on the procedure table and I go into their popliteal veins. And so we start distal, and we put our sheeths behind the knee in the popliteal vein. And one of the hardest parts of this procedure is getting into an occluded vein.

And a lot of times, like when I read the venous duplex, the popliteal vein will be totally occluded. And I'm sort of getting ready for a tougher access to get into an occluded vein to start the procedure. And by the time I start the procedure, their vein's open, because the clots sort of improving.

And I see that a lot. And just in, usually I get these patients in within a day or, and so I see a rapid improvement sometimes in thrombus burden, just with alone.

Host: So the case I presented earlier is a young woman. She's got a large PE and we'll talk about the PE in a moment, but, she's got a fair amount of residual clot and I remember being nervous about that residual clot. And we put her on, I think Lovenox at the time enoxaparin.

And I was talking to you about when can I be comfortable that that residual clot in her leg is not going to embolize? And I remember saying, you saying something to the effect of a couple weeks of anticoagulation that the clot has usually kind of stabilized, but maybe you could sort of remind me if that's right or educate us on, how long does it take a clot that you're treating to get out of the embolization window?

Robert Fenning, MD: Yeah. There could be features that make it higher risk that it could embolize. And so sometimes we see the proximal tip of the clot is called the floating tip. I don't know if you've ever, if you do a lot of inpatient medicine, you might get a venous duplex result where, if I'm the reader and I see that the proximal part of that clot is just floating around and not well adhered to the vessel wall, I call it like a proximal floating tip.

Those are probably higher risk for embolizing. That being said, I would say that it's extremely rare for people to embolize after you've started them on heparin. And I consider somebody treated as soon as you start and get their blood thinned. In fact, I think it's totally safe to manage a DVT as an outpatient, as long as it's more distal, they don't have higher risk findings or high bleeding risk.

And I think it's totally safe and it's standard of care to discharge a patient from the ER, after their diagnosis of a DVT on a DOAC. And so, I mean, we consider the patient like low risk of embolizing as soon as you start the blood thinner. Now there's going to be, like, if you take care of enough of these patients, you're going to hear, you're going to hear some stories, very rarely of a patient, maybe having an pulmonary embolism within a day. But it is extremely rare.

Host: That's reassuring. It comes up a lot and I worried about it in this young lady.

Robert Fenning, MD: Yeah, I mean, I tell people like if I read a venous duplex, I read a lot of, I, I read a lot of vascular studies at Presby, and so if I see a floating tip on a patient who's in the ER, I'll call the ER doc and be like you should probably obs this patient overnight, just because it's, it has some high risk findings.

You know, it's not well adhered to the wall, but I would probably send them home the next day, frankly.

Host: So let's talk about the procedures themselves in the situation in which you are going to intervene on a patient. So they have a common femoral's fully occluded, as you said, that's sort of the standard, that place that you would start to consider this procedure. And, I had always understood it broke down into sort of thrombectomy versus thrombolysis. Maybe you can explain the difference between those two when you might employ one over the other and so forth.

Robert Fenning, MD: Yeah, good question. So when I first started doing this, this is my 11th year as an Attending, and when I first started, there really, there was maybe one thrombectomy device that didn't work that well. And so most of these patients, I would go into their popliteal vein and cross the blood clot and I would put an infusion catheter, which is basically a long catheter with tiny little holes all around it.

And I would park those patients in the ICU for a day or two with a bag of TPA running through that catheter. And so that's catheter directed lysis, and that's how I treated all these DVT patients. So it was sometimes one or two days in the ICU, then I would bring them back to the cath lab after one or two days, take some pictures to see what's left over, and then I would use that device that didn't work that great to suck the rest of the clot out.

And so it was a two to three day ICU stay. Nowadays, I almost never do that because over the past five or six years, there's better and better devices to extract the thrombus and it's called a thrombectomy. And so basically there's two devices that I use primarily. One's like a vacuum cleaner, a big tube that sucks it out, and one is, almost like a snowplow that drags out the clot with a bag behind it that kind of collects the clot. And so I use one of those two catheters now and I almost never do thrombolysis.

Host: Hmm, that's fascinating. So you don't even bother having to go to the ICU on a heparin drip or anything they can go back to the floor now with a cleaned out vein.

Robert Fenning, MD: Yep. Usually send them home the next day. The thing that I find, a lot of these patients, and I think your patient probably had a left leg DVT. A lot of times what I find is that these patients have something going on in their central iliac vein that needs stenting at the same time.

And the most common, the most common anatomical abnormality is called May Thruner Syndrome, where basically the right common iliac artery compresses the left common iliac vein against the spine. And there's a compression syndrome that then kind of makes someone prone to have a large blood clot. And that could only, that can only happen on the left leg, just the way the anatomy is.

And so if I see like a young person, a young female on oral contraceptive pills, they have a large proximal left leg DVT; after I clean all that clot out, I'll use this intravascular imaging called IVUS, intravascular ultrasound, and I'll diagnose that issue and I'll open that vein up with a stent. And the stent keeps the vein open.

So a lot of times I'll do a thrombectomy and the patients need iliac vein stenting. There's other situations that can cause like a fibrotic stenosis in the common iliac vein, like maybe a prior DVT with some webbing. One time I had this really interesting case where this woman had these massive fibroids that cause compression of the iliac veins and she thrombosed both iliac veins.

And so there's often things we find that need iliac vein stenting at the end of the thrombectomy procedure.

Host: It's interesting you mentioned May Thurner Syndrome, and I'm glad you did because, this first came to my consciousness. I had a patient who was a snowbird, basically. She went to Florida in the winter, an older lady. And she, had a DVT and then, this was diagnosed and she was told that she needed to come back up here and find, she was just about to leave, to come back, and find an IR, an interventional radiologist who would deal with May Thurner syndrome.

And I had never heard of it. I had to look it up. And then several months later I saw another patient. And, it was the same question. So it appears that this is, at least it's relatively new, newly recognized, at least in my universe. Is that right?

Robert Fenning, MD: Honestly, it's just an example of like something that we don't get taught. I mean, May Thurner Syndrome has been described for a long time. And it's just something like I never heard of either until I like started doing this and now I encounter it a lot, because I'm in the field.

But it's not something new. You probably are hearing of more patients getting stenting for it. And that could be a combination of a lot of things and not necessarily, increased prevalence of the disease. But just more recognition of it. And unfortunately, potentially just more, let's just call it, doctors who are excited about doing procedures on it because it's actually very, it's actually an extremely common variant where if you did CT venograms on everybody in the world, you would find a very, like 15 to 20% of patients would have some sort of compression that you could see on a CAT scan. But it doesn't mean it's clinically significant. So it's sort of a spectrum. And you know, if you get too far to the side of the spectrum, it could become pathologic.

But if you start looking for it for patients with leg swelling, which is extremely common, leg swelling is a massively common complaint. I see it all day. And if you start to go looking for it on everybody, you might find a little bit of it and you might get a stent for it, and it's not going to necessarily help them.

Host: So you mentioned this young woman who had, let's say she did have a large left DVT. It's sort of unusual, right? I don't recall whether she was on OCPs or not. think she may have been, but would you actually do a venogram to see if it's not May Thurner Syndrome, is there a structural abnormality there that could be addressed that may put her at risk in the future?

Have we reached the stage of that, or is that still a little early to say that?

Robert Fenning, MD: Yeah, that's a good, that's a good question. I guess it would depend on the circumstances. If I was seeing somebody who has like longstanding, chronic, unilateral left leg swelling, I would have a high suspicion that they had May Thurner. If they then developed a very proximal severe DVT, yeah, I'm going to go in there, do the thrombectomy, I'm going to fix their May Thurner.

But let's say that patient had like a distal or not so bad DVT. It's a good question. Like if they had chronic left leg swelling, then they get a DVT, we anticoagulate the DVT, should we go in there to fix the May Thurner because that was a provoking factor for the DVT? Medicine is art and there might be circumstances where that could make sense, but, you also don't want to be rushing to put an iliac vein stent in a 20-year-old, like, we don't know what the 40 year patency rates are with these vein, with these stents.

You know what I mean? So you kinda have to weigh that. And it could be hard sometimes to make a decision like that.

Host: Let's, skip down because you brought up venous stasis and I want to sort of skip down in our sort of outline to talk about venous stasis because it's the bugaboo of medicine, you know? Right. So, I, have in my practice right now, a young guy who's got Type 1 diabetes and for whatever reason has developed venous stasis.

And, it's really limiting. I mean, he is got fairly young children. He is, he wants to go to Disney and walk around and it's difficult. And, I've been racking my brain, having him see folks to see what options are there for him. Now that I know you do this work, I'm going to be sending him to you.

But he's diuretics don't work. Leg compression is a limited effectiveness. And so, what more can we offer these patients, I suppose?

Robert Fenning, MD: Yeah. It's a very good question, and I see a lot of patients for leg swelling. And when I see a patient for leg swelling, I am thankful that I'm an internist because the differential could be vast and you need to keep a lot of different things in mind. And so like when I'm going, when I'm seeing a patient, I'm trying to figure out if they have a primary venous issue or do they have venous hypertension from other secondary things?

And so sometimes the pattern of swelling is very useful. Does someone primarily have large painful varicose veins? That's usually a tip off that it's like a primary venous issue. Do they have leg swelling without varicose veins, which can sort of be a broader differential. And so it's actually like a hard, it could be a hard thing to figure out, but I'm thinking about volume overload, heart failure, venous hypertension from heart failure with preserved ejection fraction.

You can't forget the medical things like nephrotic syndrome and so forth. That can cause swelling. So you gotta keep that stuff in the back of your mind or end stage liver disease with edema. So you kinda have to keep your internal medicine stuff in my mind, as much as I don't like to do that.

But anyway, then you just have, I see a lot of patients with a lot of central obesity, and when you have intraabdominal central obesity, you're causing venous hypertension by restricting venous return. And so is the patient overweight, elevated BMI. I see a ton of leg swelling and I put this in my note and I know like people don't think of it, but I see a lot of leg swelling from decreased calf pump function, so.

A patient gets an orthopedic injury, they twist their knee and their gait changes. They're not walking on their leg as much and they get leg swelling, or they have chronic arthritic issues or, they're paraplegic and they're in a chair and they're never squeezing their muscles. So I see a ton of leg swelling from decreased calf pump function for a variety of reasons.

And so all those patients, all that stuff that I just said up to this point, there are some vein procedures and I could get into, but if you have like, swelling from abdominal obesity restricting venous return, like the vein procedures probably aren't going to help that much. And then I, see a lot of patients with leg swelling from lymphedema.

So lymphedema is like very poorly understood, both in medicine and frankly in the vascular world. But patients can get a certain pattern of swelling, and it's sort of a physical exam finding that will diagnose lymphedema where they have swelling of their forefoot and toes. Usually venous hypertension doesn't cause swelling of the foot and toes, so it's called a Stemmer sign.

Anyway, I see a lot of patients with lymphedema. Now, what causes lymphedema? So obesity can cause lymphedema. Recurrent lower extremity infections can cause lymphedema. The most common thing I see is patients with a history of prior intraabdominal surgeries or hernia surgeries, and so they get a type of swelling pattern that's consistent with lymphedema.

None of the vein procedures help those types of swelling. And then I see patients with primary venous insufficiency. These are patients with like, kind of none of those other things I mentioned. And they have venous insufficiency and those patients can improve with some of the vein procedures that we do. And so if I saw your guy, I would kind of go through like a general history, kind of rule out all those other things, then I would get an ultrasound. And I order it a special way where the technician's going to look for venous insufficiency. So they have the patient stand up and they ultrasound their veins and they're looking for blood flowing backwards against, back towards their feet and they're measuring the diameter of their superficial veins, to see how severe their venous insufficiency is. So there are vein procedures we do in the office that can treat superficial venous reflux.

Host: That's, terrific. In the office?

Robert Fenning, MD: Yeah, there, they're office-based procedures where we go into the great saphenous vein with a catheter.

And the catheter uses heat energy to injure the inside of the vein, and essentially it shuts the vein down, and diverts blood flow to the healthier deep veins. 20 years ago, surgeons would do this vein stripping, where you'd bring them to the OR and make large incisions in the legs and physically remove the veins.

No one's doing that anymore. Because these office-based procedures are much less invasive. These vein procedures work best for painful varicose veins. So bulging large varicosities. They tend to work the least for just the symptom of leg swelling, even if they have just primarily venous insufficiency causing their leg swelling, for some reason, they don't help that as much.

But, they can help, like the heaviness and the pain and the discomfort that comes with these venous insufficiency symptoms. They can a hundred percent improve healing of venous ulcers. So, if I see somebody with a venous ulcer that's primarily from venous insufficiency, I'm strongly recommending these vein procedures. They'll decrease the frequency of the ulceration. They'll help them heal faster. And there's like New England Journal randomized control trial data for that.

Host: Rob, this is terrific. I mean, this is terrific information because I love that teaching point you mentioned about distinguishing lymphedema from venous insufficiency is, we've all seen patients that have swelling of their forefoot and toes and making that distinction upfront because I guess in that case, there's no point in sending them to you.

Robert Fenning, MD: Yeah. I mean, I, I see it a lot. So I have tricks that I can give patients. I have like, there's a lot of things I show people that can help them. But yeah, I'm not doing procedures on them.

Host: I've taken, I think three groups of patients that now I'm thinking about that I should be referring potentially for procedures. One that I may not have in the past. One is the, um, I guess and I can do the routine lower extremity edema patients. But I think the ones that may be the, with truly asymmetric edema, particularly if it's on the left, where you said the May Thurner was affected, those folks I should probably think about getting to you because there may be a structural abnormality there.

And then the other group of patients, because we see patients with varicose veins all the time. I mean, we have, older men and older women, not older that much, older forties, fifties, sixties, who, have some varicosity. It appears, to me, often to be simply a cosmetic issue, but I also know the patients that you're referring to where they really have bulging, rope like varicosities, and it sounds like those folks I should be sending to you.

Robert Fenning, MD: So if you send me a patient with the real deal bulging varicosities, and I see them, I ask them if, they're symptomatic from the varicose veins, and if they tell me they're not symptomatic, then I'm not doing procedures on them. So I would refer patients who have symptoms from their varicose veins.

Because those are the ones who are going to kind of benefit from the varicose vein procedures. And, furthermore, when I see these patients, if they haven't tried 20 to 30 millimeters of mercury knee high compression stockings, I always start with that, for two reasons. Number one, insurance companies will not cover procedures for symptomatic varicose veins unless the patient has tried compression stockings for two to three months. So if they see me and they haven't tried it, I mean, I recommend it because I have a lot of patients who tried and they like it and they feel good and they don't need procedures, and that's the end of it.

But I think it's like a hoop that the insurance companies make you jump through, but it's a legit hoop. Like you gotta try conservative management first. So if you're going to send a patient who has symptomatic varicose veins who may want something, have them try stockings and by the time they get in to see me, we can talk about whether or not they helped enough.

Host: And so actually let's talk about stockings. I'm going to go like this is going to be dumb questions about venus compression stockings. So, I'm going for my residency days because I don't think I have any updated knowledge since my residency time. But there was sort of the typical venous compression socking that could be bought, just at a retail store.

And those were not felt to be particularly effective, and the reason was because they weren't necessarily graded to the changes of contour of the leg. So we were told that no, you needed to actually have a patient go to physical therapy. So they get measurements done, so then they get ordered formal, graded compression stockings.

And then you mentioned, the millimeters of mercury standard in terms of the pressure. And so can you just educate us on compression stockings?

Robert Fenning, MD: This is not a dumb question. Like, I didn't know any of this stuff, before, and I see patients all day long who they're no one knows. No one knows this stuff. So medical grade compression stockings, you do not need like a medical prescription for these, you can get them on Amazon. And so actually when these patients come in to see me, I have a dot phrase in Epic that prints out the instructions for ordering these on Amazon. The medical grade compression is considered 20 to 30 millimeters of mercury. There's four grades of compression stockings. There's eight to 15, there's 15 to 20, there's 20 to 30, and there's 30 to 40. Whether you go to a medical device store or you go to lymphedema therapy at Good Shepherds or you go to Amazon.

Those are your options. And so, there's a company that I tell patients to use because they have a sizing guide where you measure your ankle and calf circumference, and they have a sizing guide to pick the correct size based on your ankle and calf circumference. I rarely recommend patients, I rarely recommend thigh high compression stockings, but they have them.

And so you could just measure your thigh circumference. I find that patients, even if they have varicosities that run up all the way up the leg; the thigh high stockings are kind of tougher to get on, and they ride down a little bit and they're annoying. So anyway, yeah, the most important thing is that they're 20 to 30 millimeters of mercury.

I usually recommend knee high, even if the varicose veins go up to the thigh and you can get them on Amazon. The company I tell people to use is EVO Nation, but there's a bunch of companies on there, and the most important thing is that they have a sizing guide and that they have that millimeters of mercury.

But yeah, there's nothing like, and so. And so Kendal, if I see a patient who just has like, run of the mill symptomatic varicose veins or some mild swelling, at the end of the day, I'm recommending these stockings and for the patient to buy on Amazon. The problem is if a patient is so swollen, and we've all seen these like massively severe lymphedema patients whose leg is, whose legs are huge, and even in the morning when they wake up, like the leg is still huge.

Those are the patients I'm referring to lymphedema clinic for like custom compression stockings. Because, they're just too outta control to start with a stocking. You need to have like a normal, a relatively normal sized leg in the morning when you wake up to put a stocking on.

That reminds me like one of the most interesting patients I ever saw for leg swelling was a guy whose back was so bad that he could only be comfortable in this one position where he would sleep standing up with his upper body hunched over like the kitchen table. And that's how he slept. Because his back was so bad and his wife brought him in for leg swelling.

And it was really like, his legs never got to normal because he wouldn't sleep. And when you're sleeping, your legs are kind of elevated to your heart and all the leg swelling usually improves when you sleep.

Host: I mean, I sort of, these positional issues, being supine at night or the calf pumping. You mentioned all of these are playing a role, right? It's why immobility and all of these things are risk factors for clot and so forth.

So, this was really great actually. So we talked about acute DVTs and now we've talked about venous stasis management and a bit about superficial venous varicosities. Is there anything else that you think we should know in that domain that we haven't covered?

Robert Fenning, MD: Yeah, I think, those are the main issues. I mean, I agree that most doctors, when they see patients with varicose veins, they kind of consider it a cosmetic thing, but they could be quite painful and annoying. And so I only do procedures on patients with symptoms. Well, that's not true.

If you don't have symptoms, you can pay for some of the procedures like out of pocket. It's called medical sclerotherapy, where we'll inject like superficial spider veins with some sclerosing agent to shut them down. If you don't have symptoms, like you could pay out of pocket for that stuff, but so yeah, I mean, all the patients I'm treating for varicose veins are symptomatic and they're pretty miserable.

They could be quite miserable from it. It's interesting how you could see patients with the most severe varicose veins and they're like, they don't bother me. And it's like, okay. Or you could see some patients with like much smaller ones who are really kind of miserable. So it's a weird spectrum. There's not always a connection between like severity of venous insufficiency and symptoms.

But, I think anyone with a venous wound. How do you know if a wound is a venous wound versus an arterial wound? Well, any patient with a wound I think should see a vascular specialist, a lower extremity wound. But, venous wounds are usually in the medial, like medial lower ankle area.

They call it the gaiter region for some reason. So any patient with a venous ulcer should really see like a vascular specialist and probably consider vein procedures and so forth.

Host: Yeah, I think the biggest difference I've always thought of in terms of venous versus arterial wounds is that venous wounds are wet and arterial wounds tend to be dry.

Robert Fenning, MD: Yeah. But it is, location is also equally useful. And so the venous ulcers tend to be up like above the ankle, whereas arterial areas are usually on the toes or like the pressure points of the foot.

Host: That makes sense because you obviously the problem is getting blood flow out to those nether regions and so you can have symptoms. Yeah. That's, great. So, let's go back up to my patient. There were two other questions I wanted to address with you on this patient.

One is how we would manage her DVT. How we would manage her PE and where the evidence has evolved there. And then I want to talk about filters as well. But just to remind you, this is a young lady had residual DVT, but had a, fairly significant PE. She had right heart strain on her echo.

She was tachy. She tachy, probably low 110s I mean, she's a young woman and she was responding appropriately, but holding blood pressure fine. So, my understanding of the PE severity classifications, reviewing the evidence on this, so you divide people into high risk, intermediate risk, and low risk.

The high risk folks are hemodynamically unstable. We're going to talk about it in a minute. But these are folks that are candidates for systemic thrombolysis. Based on the studies. Then you have the folks that are low risk. They're neither hemodynamically unstable or, have any evidence of RV dilation on their CAT scan.

They have no evidence of RV strain on their echo. They're low risk. They can even probably just go home from the ED. But then the troublesome folks where this young lady actually was, intermediate. I mean, she was having a vascular response, I mean, a hemodynamic response. She was very tachy.

I don't recall if her tropes were high or anything else. But she did have RV dilation and, now on CTAs of the chest, the readings will include, this of course, Rob, I'm just saying this for the audience, a statement of the proportionality between the RV and the LV.

And if the RV is, supposed to be, I think, two thirds the size of the LV, but if it's one to one, then the patient is clearly having RV dilation and that, that can change your management, right? So this lady was in the intermediate category and so I think, the conversation you and I had five years ago was, unfortunately it was after the fact because I didn't consult you when she was in the hospital and I really regretted it.

But, should she have gone for intravascular procedure for the PE. And that's what I want to talk about is who is a candidate for an intravascular procedure for a PE? Where are we at with that now?

Robert Fenning, MD: Yeah. It's like during my time as an Attending, it's probably the field that has evolved the most such that when in my training as a Fellow, we weren't doing any PE procedures or interventions. And, when I started my attend, becoming, attending, we had just started to kind of become interested in the field.

And now 11 or 10 years later, there's more and more data coming out, to kind of guide us on what to do. But the best data is still not out yet. And we're actually, you hit the nail on the head. So there's the high risk, the low risk, the intermediate risk patients have evidence of RV strain, that could be RV dilatation on the echo, positive troponins, positive BNP, or an ECHO with RV dysfunction and RV dilatation.

So that kind of puts you in this intermediate risk category. And those are the patients who, there's a few things that could happen with those patients. Number one, they could destabilize and become, go from intermediate risk to high risk. So they could become hypotensive and sicker in the hospital. They can take longer to get better because they have a higher thrombus burden and, and RV dysfunction.

And also those patients can end up having long-term like chronic thromboembolic, pulmonary hypertensions and do poorly overall. And so they're an interesting group of patients. They're a much larger proportion than the high risk. I would say the high risk PEs are quite rare. And we've become very interested in how we should take care of those patients.

And I don't know if any of the people on the call are hospitalists or work in the hospital, but there's a lot of these, a lot of hospitals, including all the Penn hospitals, have something called a PERT team, a pulmonary embolism response team. And it's a team of physicians made up of cardiologists and pulmonary care and ICU critical care docs who discuss in real time cases that come up.

Why do we need a pulmonary embolism response team? It's because we don't know what to do with these patients. So there is a pausity of class one, like randomized control trial data on what to do with these patients. Now I say that, but it's coming out more and more and there's larger and larger trials, that are studying this, but we still don't have like the really large, great randomized control trial with really solid clinical endpoints to tell us what to do.

So we need these pulmonary embolism response teams so that a bunch of docs and specialists in the field can discuss a case and decide which one should go for intervention. So we still have pulmonary embolism response teams. At the Penn Hospitals, we participate in a large randomized control trial, and these patients are getting randomized to anticoagulation alone or interventional procedures for the PE.

So there's equipoise between those two things because there's a randomized control trial. So we don't really know, we don't really know what to do with these patients. Now I say that, but there's more and more data for the benefits of these procedures. So we're actually, even if we don't include a patient in one of these trials, we are doing these procedures in quite a high percentage of patients with intermediate risk PE. I don't know if that answered your question, but, it's ongoing. It's exciting, it's an exciting field. There's ongoing trials. There was just a trial published last week. It was presented at one of these large cardiology trials, where a specific device company did a randomized controlled trial between anticoagulation and a thrombectomy procedure with their device.

The outcome was like 48 hours later, they checked the RV to LV ratio and they showed that like the procedure significantly improved the RV function. Now these trials are using like surrogate endpoints, right? Because nobody cares about the RV to LV ratio, right? Do you care about that for your patient?

Like no. But you're, making an assumption that that surrogate endpoint, which is much easier to study and to get to two days after the procedure, to study it, you're assuming that that improvement will improve them overall. That they're going to feel better quicker, that they're going to be less likely to progress to a massive PE, that may be in two years they'll have less chance of pulmonary hypertension.

So a lot of these trials. There's a lot of data for these shorter outcome, surrogate endpoints, heart rate, pulmonary systolic pressure, RV to LV ratio. And so there's more and more data showing that these procedures improve these surrogate endpoints. We are still enrolling and in, and awaiting these large, larger trials with like the clinical outcomes that you are interested in.

Host: And I saw that, it actually came across my Twitter feed that study, and I think it was my Twitter feed. And I looked at that and I was frankly a little disappointed because I thought it was so surrogate in its outcome. I was like, come on, we don't have better than this yet? This has been going on a long time.

Robert Fenning, MD: No, we don't, takes a lot of effort and a lot of time.

Host: So let me ask you, I want to frame this a little bit because, if you look at the PE data, the systemic thrombolysis works, PEs improve. The problem was in those studies, the higher bleeding risk, and I never quite understood that. Because there seemed to be a higher bleeding, in those systemic thrombolysis than were seen in say, systemic thrombolysis for, coronary events or for stroke.

And I always wondered, is it because they may be used a different dose of TPA? I never fully understood that.

Robert Fenning, MD: Yeah. It's a good question.

Host: But it made me wonder if maybe it was just sort of a one time thing that just, there were more bleeding rates in that particular trial.

Robert Fenning, MD: I mean, listen, like it's a patient population thing. Like how many of these massive PE patients have like metastatic cancer, like probably way more than patients who are coming in with an acute MI in their fifties. So, if you just consider like the underlying diagnoses more comorbidities, you know, I could imagine that there could be a medical explanation why.

Host: And so my logic in thinking about this was that if you have a procedure now that has less bleeding risk, but you're still getting what the systemic thrombolysis did, which was to dissolve the clot, you're still getting achieving that outcome, then it should be great. Right. And, I don't know if you're still doing thrombolysis or now you're doing thrombectomy for PEs as well, but if you're not even doing any thrombolysis, I mean no, no anticoagulant is used then you would think that, the bleeding rates would be a lot less. Right?

Robert Fenning, MD: Yeah, so some patients, Kendal, are too sick to even bring to the cath lab, like they're severely hypotensive. And they are too unstable to either transport to the cath lab or, they can't tolerate lying flat or a little bit of sedation. So, some patients are just too acutely sick to undergo the procedure and they need the systemic TPA at the bedside.

 Actually some of these patients we're putting, believe it or not, we'll put them on ECMO, with our CT surgery colleagues. And once they're stabilized on ECMO, then we'll bring them to the cath lab to do the thrombectomy. I mean, these are like, you're only going to experience these if you're like an intensivist, you know what I mean? But anyway.

Host: But, are you doing less thrombolysis and more thrombectomy for the PE patients as well? You had said that you were doing that for the DVT.

Robert Fenning, MD: Yeah. You know, again, these devices are getting better and better and so, doing catheter directed lysis, these patients have to be in the ICU overnight, for close monitoring. And so if we can get in and get out and get all the clot out in a single procedure, it's much more preferable.

Host: So, the way I set that up was sort of to say I would expect that these trials, once we actually get them, are going to be positive, positive to the favorability of intervening because we know that patients benefit from having their clot removed. We know that from the, and then they'll have less bleeding risk.

Robert Fenning, MD: Correct, but the anticoagulation does resolve it too. So, we see a lot of improvement in these patients. The real question is, the other arm, like, they have gotten better with anticoagulation alone. And so, yeah. I mean, I think they need to be done. I agree with you. I think we're all kind of looking forward to seeing positive results, but, we don't have like the big blockbuster clinical trial that you want to hear me say we have right now. But it's coming.

Host: So, Rob, this has been great. There was a couple areas I wanted to tackle. I mentioned filters, but, actually maybe we just do one minute on filters.

Robert Fenning, MD: The most interesting thing about IVC filters that we're learning more and more is how bad they are Kendal. So, really the only time I'm putting an IVC filter in is when a patient cannot tolerate anticoagulation and they have an acute DVT. It's pretty rare.

But, IVC filters are bad. They cause issues when they're left in long term. They can like perforate through the IVC. They can perforate bowel, they can perforate the aorta. They could embolize, they can fracture. And so the, like, I, I'll put a pa, I'll put an IVC filter in a patient who needs like some temporary interruption of their anticoagulation and they have high risk features and then I'll take it out within a couple months. But the thing that we've learned over the years is how bad IVC filters are.

Host: Yeah, and it's actually an interesting, I used to teach a course years ago at the med school in clinical decision making. And, IVC filters was what we would use because there wasn't really any good evidence. So when you had the med students going out to look in the literature, it was all these case series, and yet, at the time it was fairly ubiquitously used.

But as more randomized controlled trials came out and so forth, you really began to see that this was not what you had hoped that it was. So Rob, this has been fantastic. I really appreciate you coming on, an area of medicine that we all deal with, but know very little about because we're not trained in it.

So, I'm glad I'm able to show to kind of broadcast the private conversations I had with you, in the time we were together and how much I learned from you and broadcast those to the rest of the primary care community because I think they'll find them as valuable as I have. So, thanks for coming on.

Robert Fenning, MD: Yeah. Cool. I really appreciate you having me on. And, yeah, like, no question is a dumb question. I think, this stuff is not that well known. I mean, at least our Penn folks like, know how to get in touch with me. I, enjoy talking to the internists and fielding quick questions or if you ever want to run something by me, ask me if it's, an appropriate patient to see, or I could just give some, some guidance.

So, I enjoy talking to you quickly. If you ever have a clinical question discussing anything you need.

Host: Fantastic. Thanks Rob. And with that I'm going to conclude the Penn Primary Care podcast. Please join us again next time.