Latest / Behind The Knife: The Surgery Podcast / Clinical Challenges in Vascular Surgery: Phlegmasia in Pregnancy
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- Clinical Challenges in Vascular Surgery_ Phlegmasia in pregnancy === Speaker: [00:00:00] Hello, everyone, and welcome back to another episode of Behind the Knife. Today we're discussing a case that really highlights how venous disease can escalate quickly and demand surgical judgment. This is one of those cases that emphasizes the relationship between arterial and venous pathology, and why it is important to keep a broad differential diagnosis in mind. So allow me to welcome our co-hosts, Dr. Flores, Dr. Hazer, and Dr. Harrington. Let's get right into the action. We have a 25-year-old undomiciled female who is 24 weeks pregnant. She presents to the ED with a one-day history of progressive, sharp, left leg pain and swelling. She has a past medical history of type 1 diabetes. This is her third pregnancy, and unfortunately, her first two pregnancies ended with fetal demise. One was due to preterm premature rupture of membranes, and the second from an unclear reason. The emergency room tells you that they've done a bedside venous duplex which shows extensive DVT involving the common femoral, profunda, femoral, and [00:01:00] popliteal veins. She is hemodynamically stable, and labs are unremarkable. I don't know about you guys, but any consult in a pregnant patient makes me feel a bit uneasy. Who am I kidding? It makes me feel extremely nervous. So you immediately go down to see the patient. On exam, she has a swollen, tense, and tender left lower extremity. The swelling is obvious from the foot all the way up to the hip. The limb is cold and pulseless. She has decreased sensation and motor function. Dr. Hazer, can you walk me through your thought process about what's happening with this case so far? Speaker 2: Well, Christian, like you, getting a call about a pregnant patient puts me a bit on edge. This case is no different perhaps even worse. In this situation, we aren't just dealing with a DVT anymore. There's concern for phlegmasia and limb loss. This occurs when there is a near total venous occlusion, uh, with obstruction of not only the outflow, but the inflow of the arterial circulation. And although [00:02:00] there is nothing inherently wrong with the arterial system, it does represent acute limb-threatening ischemia. When you have a presentation like this, anticoagulation alone is not enough. You're dealing with a time-sensitive venous emergency, and pregnancy doesn't change that. It just complicates how you execute the plan. Speaker: That's a key point, Dr. Hazer. Pregnancy raises the stakes, but does not change the diagnosis or the urgency of the intervention. Is there anything else that we need to do before taking this patient to the OR? Speaker 2: Well, even though anticoagulation isn't enough to reverse the problem, it's important that, that you start it as soon as possible to prevent clot propagation. Speaker 3: Yes. I think in this situation, an ultrasound of the baby, ultrasound of the leg, and baseline labs are all you need before taking to the OR And of course, start them prompt anticoagulation. It would be nice if you can also get an ultrasound of the IVC [00:03:00] and iliac veins. However, with a large rapid uterus, it may not be easy to get a good view. Speaker: So Dr. Harrington, in situations like this, what additional workup would you get if the patient wasn't pregnant? Speaker 4: Oh, 100% I would get a CT scan. Speaker: Really? Even though you knew you were gonna take the patient to the OR either way? Speaker 4: I mean, yeah, it, it's pretty quick to do. It only takes, uh, you know, five, 10 minutes. The reason you get a CT scan, especially if they're not pregnant, is in case you need to stent. You wanna see that there's not an obstructing mass or something else that instigated this beyond, say, like a May-Thurner compression. Speaker: I see. Speaker 4: Yeah. Even if you have phlegmasia, the delay of the CT scan shouldn't be so much that it should cause irreversible limb ischemia. Speaker: Yeah. And I guess you're heparinizing the patient at this point as well. Speaker 4: Yeah. Obviously, you should start heparin immediately as soon [00:04:00] as you know there's a DVT. Speaker: Okay. We've established a diagnosis and the urgency of our intervention. The second trimester is also generally considered a safe period for general anesthesia. Surgeons are now even operating in all trimesters. When taking this patient to the OR, is the plan definitely for an endovascular approach? Dr. Flores, I imagine that before the days of endovascular, all of these were done open. Can you talk about that a bit? Speaker 3: Yes. In the old days, uh, an open thrombectomy was one of the options, but it was a very bloody procedure. Subsequently They were minimized in non-pregnant cases with thrombolysis and up to now in which you have new tools, uh, ch- mainly related to aspiration thrombectomy or combination of thrombolysis with thrombectomy and so forth. Speaker: So do you think that would be an option in this case? Speaker 3: Open, probably no. [00:05:00] Open, open embo- uh, embolectomy are very bloody. I see. You may lose a lot of, uh, blood. Um, I have done open, uh, venous reconstruction for other reason, not in pregnancy. Okay. When you have a chronic occlusion associated with disruption of the vein and do a femoro-femoral bypass with a synthetic graft. I've that, I have that. Speaker 4: Yeah. Speaker 3: But not in pregnancy. Okay. I think you- You tend to be... Yeah, you can mi-minimize, uh, blood loss. Yeah ... but I haven't searched the literature saying, uh, have you done, uh, open thrombectomies in pregnancy? I will leave that as a last resort. Speaker: Yeah. These days I don't think I've seen many or any really open embolectomies for venous disease. Speaker 2: Yeah, I, I think, uh, that's in part because we have so many great endovascular options and, uh, uh, we'll touch on those later. [00:06:00] Speaker: Good point, Dr. Hazen. We do have a lot of endovascular options these days. Uh, so let's continue with the case, and then we can talk about the different options a little bit later. So the patient was taken to the operating room. The popliteal vein was accessed under ultrasound guidance using a micropuncture kit. Fluoroscopy was used to confirm entry and graduated dilation was performed. Intravascular ultrasound, or IVUS as we'll call it from now on, was used to reduce radiation exposure. Once sufficient dilation was achieved, the ClotTriever was advanced. Mechanical embolectomy was then performed with two passes of the device. There was marked improvement in the appearance and rapid flow into the IVC via the now open iliac vein. The flow in the femoral vein was also greatly improved. Following this, arterial doppler signals were appreciated in the foot. Dr. Harrington, can you talk a bit more about IVUS and how it was useful in this case? Speaker 4: Yeah. So Christian, IVUS is a unbelievably great tool. It's getting used [00:07:00] for all sorts of procedures now, especially venous procedures. It essentially gives you a cross-sectional view of the vessel and can help you assess clot burden and extent of, uh, the thrombus a lot more accurately than standard angiography. Another obvious benefit is the fact that it avoids radiation, uh, which makes it extremely useful in, say, the current case where the patient is pregnant in this case specifically, after the thrombectomy was performed, IVUS was able to show us that although the majority of the thrombus was removed, there was still some element of iliac compression, uh, likely from May-Thurner syndrome. Speaker 2: Yeah. You could say there was an element of baby Thurner. I, I did wanna add a couple of caveats about this particular case. Because of the gravid uterus, we couldn't place the patient prone, so we placed the patient in a [00:08:00] decubitus, uh, a lateral decubitus position, and then actually- Yeah ... accessed it from the side, which was a little bit, uh, novel in terms of trying to, uh, look at the, uh, ultrasound in front of you and seeing where the popliteal vein was, and you're approaching it from a side view, so it took a little bit of imagination. And the second thing, it was that we really tried to limit the amount of radiation that we were giving, but passing the wire up into the IVC was not as straightforward as I would've liked, and therefore we did have to use some radiation. Initially, we shielded the baby, but what that resulted in was increased sort of, effort by the uh, C-arm in terms of the amount of dosage that might have been being delivered. And therefore, we had to move that shield off and just use very limited spot [00:09:00] fluoro in order to access and get through the uh, occluded uh, iliac system. Speaker 4: Paul, was there a reason you couldn't frog leg the patient? Speaker 2: Well, it's not as good for the baby at that, uh, time to have the patient on their back, and I've had a lot more trouble getting in from a frog leg approach when the patient's on their back. So, it, it, I, I find it actually now you're working upside down as opposed to from the side. So this, this approach with several pillows on the side was protective for the baby to be off the IVC and also, uh, uh, made it easier f- uh, as much as it was a little bit more difficult than the usual, but it made it easier than when I've tried to go from a frog leg approach. Speaker: Wow. Yeah. Overall sounds like not a very fun case, to be honest. Uh, why don't we talk a little bit more about May-Thurner? So we said we used the ClotTriever, uh, we removed most of the thrombus, and then the IVUS showed us that there was still some extrinsic [00:10:00] compression, which we said usually is from the iliacs, but also in maybe a bit from the uterus in this case. Uh, so Dr. Hazer, maybe you can tell us a little bit more about May-Thurner. Speaker 2: Yeah. So essentially, May-Thurner is de- defined as a compression of the left common iliac vein, uh, and sometimes even the right, by the right common iliac artery it, it's a funny asymptomatic left iliac vein compression seen in about 25% of healthy adults. There really isn't a cutoff in terms of the compression is where we would say, "Now we consider this May-Thurner." It's more about symptoms, especially when you have a young patient with chronic leg swelling and workup so far has been unrevealing. Speaker 4: Uh, yeah, you know, just to go off what, uh, Paul was saying a little bit. IVUS obviously is, as I mentioned earlier, is very important, especially in diagnosing and treating May-Thurner compression. So first of all, it gives you a very precise, exact [00:11:00] location and extent of the compression which helps with guiding stent placement. And I have also seen a couple of instances where the stent gets left in the iliac and is protruding out into the IVC. And when it does that, sometimes, uh, it can act as a nidus for thrombus formation. Uh, with IVUS, you can place the stent a little bit more precisely. With some of the older stents, though, you do need to extend out into the IVC at least a little bit. Um, the other thing is IVUS can help in confirming the appropriate size of the stent much better than angiography. You have to remember that the vein is gonna change sizes as the blood moves through it. But the IVUS gives, you know, a real-time view of the [00:12:00] actual size of the vein. Therefore, it's, it's much more accurate. Speaker 3: Yes. Uh, there is no question the IVUS has been a very significant improvement, uh, dealing with this type of problem. In the old days before IVUS, I used to use angioplasty balloons in order more or less to size the iliac veins and, uh, help out the size, the size of the stents. And now we have also self-expanding venous stents, which are more compliant and more resistant to fraction and external compression. Speaker: Yeah, before working on this case, I actually didn't know that there were dedicated venous stents. Uh, Dr. Harrington, can you talk a bit more about the problems with the older so-called wall stents, uh, that led to the introduction of specific venous stents? Speaker 4: Uh, yeah. Um, so I kind of briefly mentioned it but so [00:13:00] previously, wall stents were being used for venous stents. They, they're not designed specifically for the vein, although they are currently approved for vein, uh, venous interventions. They work good. They still are. Um, they have some drawbacks. Firstly, these stents can foreshorten a little bit as they expand. The, um... Additionally you know, with this foreshortening, you're trying to make sure that you get the whole area of compression. So people tend to be a little bit aggressive about, uh, placing the stent a little bit into the IVC. I've seen a few where they almost completely jail out the right side iliac vein. Uh, this can lead to problems, obviously, with the outflow from the right side. And I've actually seen several times where people presented to me after being stented at outside [00:14:00] centers with with now clot, you know, extensive DVT on the right side. Speaker 2: The other thing I, I've had happen with the wall stents is that I've had balloons pop because the end- Yeah ... of the stent can become very sharp and pointy. And so you have to be very careful if you're post-dilating them with an angioplasty, particularly because a lot of the balloons that we have available are, are not the thick Atlas or Conquest type of balloons, which have a, a thicker outer membrane. And, and it can become really quite problematic if you have one of the older Excel balloons rupture because then you can't shrink it down, and you have to go in with a larger sheath in order to recapture it. I mean, I... It only happened to me once where I, I really was sweating because I... the balloon got caught on the stent. Mm. Oh my God. And, and it was... I was, like, pulling out the venous system, and [00:15:00] I, I, you know, it, it led to an hour of panic, Yeah ... of trying to recapture that balloon off the stent. So I'm very, very ca- I, I do wanna mention that, and I wanna mention the fact that you... You know, part of the problem is if you angioplasty the wall stent in the middle, the outer edges narrow. Speaker 3: Mm. Speaker 2: So because of the way that it's designed, it's all one, one particular coil. So you're, you're officially supposed to angioplasty the endpoints first, but you have to be very careful that the balloon And a lot of the older balloons have a long shoulder on either side, so you have to be m- very careful the balloon is all the way inside the stent, and that you- Mm-hmm that you also aspirate it out fully before you start to move it, or it can catch on the stent, pop, and actually get caught. Speaker 3: Yeah. Another problem, uh, I have seen with wolf stents is dealing with asymmetrical stenosis, especially in the left brachiocephalic trunk, [00:16:00] in which the stent will migrate and shoot up because of the logistic problem that Paul have described. You know, you cannot center in the- Speaker 4: Yeah ... Speaker 3: y- at the point of the stenosis because of the- Sure ... you know, a- a- asymmetrical stenosis of that particular vein. Yeah. So you have to be very careful. Speaker: Wow, that's really a crazy story, Dr. Hazer. Uh, in this case, we didn't treat the maternal with a stent at the time of the initial procedure. Uh, can you walk me through that thought process a little Speaker 2: bit? The main reason I decided to defer was because the patient was pregnant. I wanted to limit her time of anesthesia, and also wanted to shoot less fluoroscopy. Besides limiting the radiation, placing a stent in the pelvis may not be the best idea because the uterus is still growing. Although the venous stents we have these days are more compliant and pliable, the risk of stent fracture isn't zero. [00:17:00] And if the patient wasn't pregnant, I would have probably stented then and there. Speaker 3: Uh, indeed, there are not many reports of, uh, BBT in pregnancy. And, uh, looking to some of the report, it seem that most of the cases tend to defer the placement of the stent for after the pregnancy, and minority will place a stent at that point in time. Speaker: Okay. So we've touched on IVUS a bit. Uh, Dr. Hazer, can you talk a bit more about ClotTriever, which is a form of mechanical thrombectomy, and why you chose that over, let's say, something like AngioJet? Speaker 2: Well, uh, Christian, regarding AngioJet, it's probably most effective when combined with active thrombolysis. Sometimes we leave the catheter for 12 to 24 hours after the intervention, just dripping tPA into the vessel, even up to 72 hours in some specific cases. And although alteplase itself has very limited [00:18:00] effect on the baby in terms of crossing, crossing the placenta, it still puts the mother at risk for hemorrhage. I know in the stroke world, the recommendation is to give tPA when there's a severe stroke in a pregnant patient and the risk of maternal hemorrhage is low. But I think in this situation, we have a tool that could avoid using tPA altogether. And so better use, uh, the situation was to use a mechanical device Yeah. Speaker 3: Yeah. Uh, this has been advances. At the beginning, we went from open to anticoagulation and thrombolysis only, and for a while enhanced thrombolysis, and then aspiration thrombectomies- Yeah ... which minimize the blood. So this is a constant evolution. The question is the technology keep changing. Sometimes they carry larger catheters, smaller catheters, suctions, and so forth. And with the introduction of the intravascular [00:19:00] ultrasound, you're able to determine the etiology o- of the problem. Speaker: Yeah, all great points from everyone. For those at home, AngioJet is a form of mechanical thrombectomy that uses rheolytic therapy. This means that it uses high velocity saline jets via a catheter to break up clots. It also creates a localized low pressure system which works to evacuate the thrombus. You also have the option to activate power plus mode, which helps deliver lytic therapy directly into the clot. It isn't mandatory to use TPA, but it generally is considered more effective when you combine the two. ClotTriever on the other hand is similar in that it is a form of mechanical thrombectomy. It uses a sort of mesh collection bag and a nitinol coring element to manually remove the clot. I've sometimes heard the ClotTriever referred to as a bloodless thrombectomy. There haven't really been any randomized control trials that directly compared catheter-directed thrombolysis with mechanical [00:20:00] thrombectomy. However, based on the studies available, they do seem to have similar outcomes with a slightly higher risk of bleeding in the thrombolysis group. AngioJet also has the added risk of hemolysis from the force of the jets used. This can lead to hemoglobinuria and even renal failure in some cases. Again, the use of thrombolysis in AngioJet is not an absolute contraindication in pregnancy, but there is a very real risk of maternal hemorrhage, especially at the placenta, which must be considered. Dr. Harrington, thoughts? Speaker 4: So many thoughts. I mean, number one, ClotTriever is definitely not a bloodless thrombectomy. You can definitely lose a fair amount of blood. Um, this is especially true if you're not just using ClotTriever, for example, when you're incorporating a suction, uh, thrombectomy too. Inari has their FlowTriever device too that does suction. Sometimes you use that as well, and when you're doing these DVT [00:21:00] cases, I, I personally feel you can lose a fair amount of blood. Uh, the other thing is you mentioned AngioJet. So it's interesting. I remember when I was a resident or fellow using AngioJet sometimes for venous thrombectomy or pharmacomechanical thrombolysis cases, but, you know, when Inari came out, I think a lot of people shifted away from that. And I think People were already shifting away from that because of several... And, and again, I have no stock in any of these companies. Issue- I have no, like, personal issues with AngioJet. I think it's a great device, but I use it for other things. But specifically people had issues using AngioJet during these extensive clot cases. Uh, Dr. Flores, I know has mentioned it to me, and one of the main complications was, uh, you could get renal failure, but there were other things that could occur, and it made it less desirable to use it during these cases. Uh, nowadays, I think the majority of people use [00:22:00] some form of suction thrombectomy or a mechanical thrombectomy. There's a newer, uh, Medtronic device that does both, and there's other companies that are also making similar products that, uh, do both suction and mechanical thrombectomy. And what's nice about these are that you can kind of move things away from using thrombolysis, using tissue plasminogen activator. I, I still think there's a benefit to using, uh, tPA during these cases. But it's nice to be able to avoid using it, especially when there's a contraindication to using it. And I, and I want to clarify, when I'm saying all this, and I say most people, I mean myself and the people I know, not necessarily everyone. Speaker: Thanks for that clarification, Dr. Arrington. Sometimes as a resident, it can get a bit confusing with all these different brands and techniques. Hopefully this helps keep things straight. Okay, let's shift gears a little [00:23:00] bit to talk about thrombectomies in general. Let's say the patient isn't pregnant and there are no signs of phlegmasia. Should we be taking all of these DVT patients to the OR for thrombectomies or thrombolysis? Speaker 4: Yeah. The point of treating these DVTs with surgery is to minimize the clinical sequelae of blood clots, which is, uh, post-thrombotic syndrome. This happens when there is thrombus formation at the valves causing inflammatory cascade. This damages valves and leads to decreased compliance of the vessels. Valves don't work as effectively, leading to reflux and venous hypertension. Sometimes the clot never fully breaks down and the vein remains occluded, causing a blockage. This results in chronic limb swelling, varicose veins, limb discoloration, and, you know, some people end up with ulcerations and those ulcers can obviously get infected.[00:24:00] Additionally, when people do get venous ulcers under these circumstances, they can be very difficult to treat. Sometimes people have these ulcerations for years The risk is quite high too. Iliofemoral DVTs specifically have a greater than 50% risk of developing post-thrombotic syndrome, and studies have shown that the surgery may not be able to completely eliminate the risk of post-thrombotic syndrome. But with treatment, the severity improves. So I want to emphasize that one more time. You're not removing the risk of post-thrombotic syndrome. You are improving in terms of how severe it will be, uh, which I think is really important for patients to understand because, you know, you're not completely preventing this issue, but you are reducing how bad it will be. So when you have a young, healthy patient, especially with an iliofemoral DVT, I, I tend to be a little [00:25:00] bit more aggressive about treating them because they are really at high risk of developing post-thrombotic syndrome, and they're probably the ones who are gonna benefit the most from reducing the severity. Speaker: Yeah, I think that makes sense. You know, we always take age into consideration. I think ambulatory status is another big point that we've discussed, at least when we have those consults about why we should or should not be taking these patients to the OR. You know, those nursing home patients who are mostly bedbound, we usually go for medical management in those situations. Anyway, back to the case. Before leaving the OR, a four-compartment fasciotomy was performed. I think that was a fairly straightforward decision to perform the fasciotomy. Would you agree, Dr. Flores? Speaker 3: Yes. Uh, I think there is, uh, a good decision, especially dealing with limb ischemia, arterial ischemia. In the straightforward iliofemoral DVT without limb ischemia and just swelling, I probably won't have, [00:26:00] haven't done the fasciotomy. Speaker 2: I wanted to add, too, because she was pregnant we used, um, MAC, you know, monitored anesthetic control and, and, um, uh, local anesthesia. So for the fasciotomy, we were very gentle, and they gave her a little bit more sedation, and then we actually had to numb up, uh, both the incision sites as well as the, the subcu and the, and the fascia layers itself as well. Yeah. But it was, it was, uh... In her case, because of the ischemia, and she really was a Rutherford IIB, uh, ischemia e- from a venous cause, w-we felt that, uh, it was very important to do the fasciotomy. And then, and she did have initially significant, uh, edema, uh, and swelling of the muscles. So the pressure was definitely over twenty millimeters mercury. Speaker 4: It's interesting, you know, I w- one thing I would just add is it's, it is unusual to have to do a fasciotomy for [00:27:00] a, um, related to a, an extensive venous DVT where you're doing a thrombectomy. But I think you know, what Do- Dr. Hazer and Dr. Flores said is really important. So y- this is like, uh, good clinical judgment 101, which is that this patient had a DVT, but they also had limb ischemia lasting for a long time. And so if he had not done the fasciotomy, the patient probably would have had very bad compartment syndrome and, and may have also developed worse complications. Speaker: Yeah, definitely. I think especially in this patient risking another complication, like it's better to do the fasciotomy and the patient not have compartment syndrome than the intern calling you from the ICU a couple of hours later saying that, "Oh, her creatinine has gone up, her CPK is thirty thousand, and she doesn't have a [00:28:00] pulse again." She would have to go back to the OR, get more anesthesia. It, it would've just been a bad situation overall. Uh, anyway, postoperatively, the patient did well. Uh, she was kept in the surgical ICU for close monitoring and neurovascular checks. The fetus was also monitored closely with frequent non-stress tests, which is a form of non-invasive fetal monitoring. There was no evidence of fetal distress. The patient was kept on a heparin drip and then converted to Lovenox after a few days. Her fasciotomy wounds were also able to be closed on post-op day four. The patient was also seen by hematology, who sent a hypercoagulable workup. She was found to have decreased levels of protein C and S, which are anticoagulant proteins. Her antithrombin III antigen was also low. These are a bit hard to interpret as pregnancy can cause physiologic decreases in these proteins, but it may have predisposed her to be hypercoagulable. The patient was later discharged on therapeutic Lovenox. She was offered to switch to a direct oral [00:29:00] anticoagulant, but was reluctant to do this given that she was having issues with nausea and vomiting in pregnancy. Later, she was seen in the clinic and was noted to have an improvement in her swelling, although it was still present. And that goes back to what Dr. Harrington was saying. We're not completely eliminating the risk of post-thrombotic syndrome, but definitely in this case, the patient needed to go to the OR. Her repeat venous duplex showed that her left superficial femoral vein remained clotted with partial reconstitution of the common femoral vein. Her external iliac vein was open. Speaker 3: So Dr. Hazer, what's next for this Speaker 4: patient- Hold on. Hold on, because you know I was gonna harp on you about this. There's no- nobody-- we don't wanna use the term superficial femoral vein. The correct term is femoral vein. Okay. People are... have moved... Because it's confusing. Okay. That's why we don't use that in our labs, and people in, you know, the vascular world don't wanna use that term Speaker: I didn't know that was an, that was an official thing, really. Speaker 2: Yeah, Speaker 4: yeah. [00:30:00] Yeah. You're supposed to use femoral vein, 'cause superficial makes it sound like it's a superficial vein. Speaker: Okay, noted. So just to re-say that then, her femoral vein remained clotted. She did have partial reconstitution of her common femoral vein. Her external iliac vein was actually open. So Dr. Hazer, is there anything to do for this residual clot besides anticoagulation? Speaker 2: I think, as Dr. Harrington pointed out, and then she is a young patient, that because of the risk for a post-phlebitic syndrome and the severity of it being so significant, uh, that doing more work and intervening to reduce the amount of thrombus burden will be helpful for her. So I think the next step will be, after she delivers, uh, that we repeat the non-invasive studies and actually then b-bring her back and potentially even use some of the more adherent clot, uh, devices, uh, to [00:31:00] try and remove as much of the chronic clot that's there, restore flow as fully as possible and, and assess for a possible May-Thurner. The other- Mm-hmm ... thing that we absolutely have to do is have a full hematology workup to see if she's predisposed to, uh, one of the hyper coagulable factors. Oh, she was Speaker 4: protein C and S. He said it earlier. Speaker 2: Oh, you did? Speaker: No, but you can't, uh... Like, based off her pregnancy alone, if you think about it back in the day of caveman days, let's say, a lot of women used to die from bleeding from delivering babies. So it's almost like an evolutionary mechanism whereby patients, pregnant patients, are actually hypercoagulable to prevent that. So protein C and S and antithrombin III are naturally low in pregnancy, so it's kind of hard to interpret. That's why it's important to repeat the hypercoagulable workup. Oh, that's Speaker 2: interesting. Yeah. I was gonna say, because we know that the coagulation cascade factors are altered during pregnancy, [00:32:00] that we have to repeat all of those studies again with hematology, as well as look for some of the other factors. Because even some of our coagulation, uh, cascade factors are altered because of the medication we're treating patients for. So oftentimes the hematologist will wait until they can be off of all anticoagulants for a few weeks before they measure some of those, uh, levels to see. And, and maybe she has several. The other thing that we note is that these, uh, thrombophilic misalignments can often lead to spontaneous abortions or fetal loss, and so that may be part of the reason that she had lost her two previous pregnancies. Speaker: Yeah, definitely. Makes- Speaker 2: But, but going back from a vascular surgeons stand- standpoint, I think that we want to make sure that we treat any of the mechanical, uh, aspects of her pathology right now as much as possible, and also just to reinforce that she really is gonna need to wear compression [00:33:00] socks, elevate her legs, et cetera. And particularly if she plans another pregnancy, uh, that she'll know in advance that the majority of, of women don't realize that wearing compression stockings during the first trimester is probably the most effective way to reduce some of these post-phlebitic syndrome developments. Speaker 4: Also, I would mention, you know, sometimes long term these patients develop reflux also in their superficial veins, and it... Although it becomes like a little bit of a dilemma what to do with it you d- sometimes we do treat the superficial reflux as well. But that's, that's more of, uh, comes into the chronic treatment of this. Speaker: Yeah, definitely. And just to give the viewers at home some closure, I did give the patient a call. She actually did successfully deliver the baby last week, so we're happy to hear that, and she did say that she had an appointment with the hematology office next week. [00:34:00] So I'll talk to the vascular office, and we can schedule her to come back to our clinic to repeat those duplexes and reflux studies and start planning for possible stenting. All right, everyone, that brings us to the end of this episode. To bring it home, we're gonna end with some quick hits. Phlegmasia occurs when massive swelling from a DVT causes venous outflow obstruction, and the resulting edema causes arterial compromise due to venous hypertension. For young, healthy patients, especially with iliofemoral DVTs, strong consideration should be made for thrombectomy. For older or more frail patients, other considerations like ambulatory status and life expectancy should be taken into consideration prior to intervention. There are many forms of thrombectomy, including mechanical, suction, pharmacomechanical, or even open. Knowing the different techniques can be extremely useful for tailoring a unique approach based on patient characteristics. IVUS is an essential tool that's helpful in determining the size of your [00:35:00] stent, locating zone of compression, identifying potential residual thrombus, and confirming May-Thurner syndrome. Okay, everyone, we hope you enjoyed this episode of Behind the Knife and were able to take something from this talk. Hopefully none of us ever have to deal with a phlegmasia in pregnancy again, but if you do, maybe this talk can make your decisions a bit more well-informed. Thanks everyone. From all of us here at Behind the Knife- Speaker 2: Dominate the day. Dominate the day.