Talking Tall Rounds®: Managing Complicated Arterial Access

Podcast Transcript

Announcer:
Welcome to the Talking Tall Rounds series brought to you by the Sydell and Arnold Miller Family, Heart, Vascular and Thoracic Institute at Cleveland Clinic.

Christopher Smolock, MD:
Thanks for joining us today. Old devices, new problems, and we're going to talk about managing complicated arterial access, which all of us, all departments in our HVI, are intimately involved with.

Christopher Smolock, MD:
You know, the real issue is getting these large devices or things that look like them into these arteries. Usually, the femoral or the axillary or brachial, and of course, smaller access in radial or pedal arteries.

Christopher Smolock, MD:
The reason why this is a problem is traditionally complications in certain areas can go up to actually 10% and these can be quite devastating. You could see the nerves that are in this area. So it's not just a problem of the ischemia or of arterial injury, but sometimes nerve injury. Those complication rates have gone down in small access, but they still continue to be somewhat of a problem with large access and including in a lot of the patients we see, which are done emergently and under not optimal situations.

Christopher Smolock, MD:
So just to give a sense of sizing of some of these devices in French size, and this is based on PI or 3.14, and the area square is under here. So if you think about about a five or a six millimeter femoral artery, which is a little bit on the smaller side, but not uncommon in a lot of our patients, and we're also talking about an artery here that's not even diseased. You can see how a seven French sheath leaves a decent amount of area, but a 12 French sheath is almost consuming that entire diameter and area of that vessel. So, just something to think about as we continue on.

Aaron Weiss, MD:
So today I'm going to give a short little talk about the femoral access for ECMO and no disclosures.

Aaron Weiss, MD:
Now, whenever we talk about ECMO or whenever I get a consult for ECMO, the first thing I think about is, "Does this patient actually need ECMO?" Every time I get consulted for an ECMO patient, I think, "Can we avoid going on ECMO at any cost? If we need it, we need it, but can we avoid doing it?"

Aaron Weiss, MD:
So, immediately what I'm thinking about is not just right now, but also downstream. I want to talk about the insertion. I want to think about the complications that may arise and whether or not we have an exit strategy to come off of this. And this is all very important at the time you're thinking about putting in ECMO. All right?

Aaron Weiss, MD:
So, you want to think about patient indications, inclusion, exclusion criteria. What's the underlying diagnosis for the cardiogenic shock? Is there something that you can treat that avoids needing to go on ECMO? Will this patient benefit from ECMO? Can we avoid any complications taking our time with the insertion? Is it more of an emergency? Are there various different other devices that we can use instead? And then also what are the future implications? Is there an exit strategy to come off of ECMO? This all should be thought about at the time when you're thinking about putting in ECMO. Okay?

Aaron Weiss, MD:
So, there are two main ways of putting an ECMO central versus peripheral. And today we're talking about peripheral and they're various different strategies to putting in peripheral ECMO. And as you can see on the left, you can do fem-fem. You can do ax-fem, you can do a carotid-fem. And you can get really creative with a number of other ways too.

Aaron Weiss, MD:
Now, for the purpose of this talk, we're talking about femoral cannulation. There's three main ways we can do femoral cannulation. The first is percutaneous. Now the benefits, sorry, the benefits of this are, it can be rapidly done. Confirmation in the cath lab under fluoroscopy is very, very helpful and multiple different people are capable of doing this. The second one is that direct open. We do this a lot in the operating room. And the downsides of this are that with doing this, if you need to stay on ECMO, you now have an open incision that really isn't the easiest thing to close around it and it can be quite dirty. The kind of more optimal one, if you are going to do a direct surgical cutdown is to do a tunnel. Here, you can see on the left where the incisions are, well, the incision in the groin is made and the cannulas are tunneled through the skin in a different stab incision, separate from the main one.

Aaron Weiss, MD:
One of the main things I'd like to point out here is that, and we'll talk about this a little later, is that for your reprefusion sheath, this amount of length for the cannula is not necessary and only causes problems. But this is... Understanding how to cannulate the femoral artery, you have to understand anatomy, okay? Talking to the group of people in front of me right now about access and gaining access to the femoral artery. Everybody understands that the sweet zone to kind of cannulate for femoral access is the common femoral artery, prior to the bifurcation, but not above the ligament. All right? And so when you're aiming your needle down in, you really want to make sure that you're not aiming so high, that facilitating later removal of it is going to be a much bigger operation.

Aaron Weiss, MD:
So when you're thinking about putting it in, keep in mind, how do we get it out and how can we get it out, especially in obese people or people with bad peripheral vascular disease, how we can make the smallest incision possible to remove that.

Aaron Weiss, MD:
Preventing complications. You know, my preferred method of, even in an emergency, is using ultrasound, okay? Getting wires, both anterograde and retrograde, and also venous prior to inserting any cannula, all right? It's the easiest way to make sure that the rest of the procedure won't be filled with complications. We use micropuncture technique. And then after you're cannulated, it's really important, secure your cannulas. Okay? Five, six stitches, secure them to the leg. If you've ever seen an ECMO, or any kind of cardiopulmonary bypass cannula come out of somebody's going full flow, you'll understand why this is so important. Okay?

Aaron Weiss, MD:
So, femoral arterial cannulation, especially in an emergency. Are landmarks reliable? Well, not really. We know that the bifurcation of the common femoral artery can occur above the inguinal ligament in a lot of cases. And so, you can't really go by just landmarks. Is there a pulse? Well, maybe. We've all been a part of codes where the only pulse you're getting is doing active CPR and trying to cannulate an artery during that is quite difficult. Is there a color? Well, is it dark blood? Is it bright red blood? Well, during a code is the patient even oxygenating. So, you can't really go by any of this. When you are able to cannulate the artery, you want to ask yourself, "What does this patient really need?" Ask yourself, "Will this cannula support this patient through this vessel, in this clinical situation?" All right?

Aaron Weiss, MD:
Ultimately what you really want is, you want to choose a cannula that accommodates the calculated full flow cardiac index of about 2.2 to 2.5. Now, rarely is this ever needed. And actually a lot of the time it's detrimental to the patient, because you want some blood flow going through the heart. You want to prevent LV thrombus. There are various different types of sizes of cannulas and types as well. You know, the guys up at Columbia, they tend to use even smaller cannulas down to 15 French, and they seem to have very good results with that. And also much less limb complications associated with that. Now, if that 15 French can't support a 250 pound person, you're kind of, handcuffing yourself in terms of the support that's needed to resuscitate that patient for ECMO. So, you always should be thinking about how much flow does this patient really need.

Aaron Weiss, MD:
For femoral venous cannulation, you want to do careful dilatation, okay? So the PICV kits that we use 8, 12, 16, French dilators, okay? Often the femoral venous cannulas you're putting in is much larger, so this big step up. So, you want to do it over a stiff wire and often, I think that's the ProtekDuo, has a bigger dilators that you can then use. So if you're having problems getting the femoral venous cannula large enough into what you need, which you can then do is get the dilators from the ProtekDuo kit, use those, and dilate up appropriately. You want a 21 to 25 French femoral venous cannula, snaked up to the RASVC junction. You really want it high enough that the worst thing you have to do is pull it back. You can't advance it in, so you can always put it higher, or you can always pull it back, but you can't advance it further. And so always aim on the higher side.

Aaron Weiss, MD:
If you don't have thoracoscopy and don't have TE, which both of those things are our preference, then measure based off the angle of Louis, okay? Take your femoral venous cannula, go from about here, down to where your insertion point is, and make sure you know where that insertion point is, and thread it up into what you think might be the RASVC junction. And then it's important to confirm it afterwards, okay? Echo guided confirmation. All right?

Aaron Weiss, MD:
So now, the dreaded complication of limb ischemia, when it comes to femoral access, all right? So really, what does this lead to? Well, at leads to Compartment Syndrome leads to fasciotomy, limb amputation, and it's a major risk factor for mortality in ECMO patients.

Aaron Weiss, MD:
So, how does limb ischemia really happen? Well, it's really, it's a very multifactorial, very complicated sort of thing. But would you have to understand is, as Chris pointed out earlier, the 12 French cannular, including a six millimeter vessel was something like what, 50 to 60%? We're putting in at the smallest, a 15 French cannular for an ECMO. Anything bigger than that, well our average is probably anywhere between 16 to 18. All right? You're really occluding that vessel. So it's very important to get a distal reperfusion cannula in there. And that's why initially, upon insertion, I put wires anterograde and retrograde at the same time. That way it facilitates getting a distal reperfusion cannula.

Aaron Weiss, MD:
How big of a distal profusion cannula? I like bigger is better. And I like a wire braided cannula. These are, they're available in the cath lab, actually, I've been kind of jumping down to steal some every once in a while from you guys when we've needed it. But the wiring enforcement, especially in obese patients helps prevent kinking and place it laterally to the arterial cannula, all right? Especially when patients have pannus and things like that, their bellies will kind of flop over and kink the cannula at the skin and all that effort that you put into putting that distal profusion cannula, once I think clots off, we've got a real problem.

Aaron Weiss, MD:
And then how do you do it? Well, you do it under fluoroscopy. Ideally, that is the case. We did a case last week where we put the ECMO in and immediately Joe took the patient to the cath lab and under fluoroscopy, we put a distal profusion cannula and it worked beautifully. If you can't get one in via vascular ultrasound, do a cut down. And then how do you monitor your limbs? Serial physical exams is, I've found to be the most important way of monitoring this. You know, flex every joint distally, vascular surgery colleagues know this better than most of us, but the doppler signals, the oximetry, they tend to not be reliable. Even the lab values, they tend not to be reliable. So, it's really that serial exam monitoring that's going to help you salvage a limb and get to it early and help save that limb.

Aaron Weiss, MD:
So here's the good, we have separate arterial and venous on both sides. Okay? Oh, I'm sorry. An arterial on one side, a venous on another, we have a short, extra bypass circuit to the distal reprefusion cannula. Okay? Which, is right next to the arterial insertion site. This facilitates of one incision to remove both later on, all right? I've removed a few over the past year or so where I'm making multiple separate incisions, and as you can see here, unless I'm making one big one like this, you got to make multiple incisions. It's just, it's a lot more painful. All right?

Aaron Weiss, MD:
So this isn't as good as the previous slide. And obviously the worst case is the ugly. All right. You never want to let it get to this point. Okay? So serial physical exam, serial monitoring whenever you're on ECMO is of the utmost importance. And one of the last things I want to say about when you're initiating ECMO it's very, very important that you don't bring the lines up before you actually are ready to connect up. Now, if the their still circulating back there, that circulation of the prime volume is actually warm. Now, if you cut the lines and put them up there, and then you're waiting a half an hour, all that prime volume is getting cold. Now you initiate ECMO and you've got a couple of hundred CCS of cold saline going right into the heart and you can fibrillate the heart. All right? So have pads on ready to go if that's the case, but just understand that.

Aaron Weiss, MD:
So, as Ed pointed out earlier, it's very important for the tailored shock strategy. Anytime there's an ECMO patient that comes in, it's very important that the shock team understands that, that patient's there and that we can help in any way possible to kind of get that patient off of ECMO, or triage any kind of problems that exist while on ECMO. Thank you.

Sean Steenberge, MD:
I'm going to be talking about Vascular Surgery's involvement and how we avoid access complications any time we obtain arterial access.

Sean Steenberge, MD:
I'd like to start off with a case. This is a 20-year-old otherwise healthy female that went to an urgent care for shortness of breath. Was diagnosed with the flu, started on Tamiflu. However, had worsening symptoms the next day, ended up requiring to be intubated at increasing ventilatory support and was subsequently transferred to Toledo for ECMO placement. Was placed on VA ECMO. They did a left femoral cut down, 19 French arterial cannula, 25 French venous cannula, and then an eight French distal reperfusion cannula.

Sean Steenberge, MD:
The next day, she was transferred to the Cleveland Clinic. However upon arrival was noted have a mottled left leg. There was no flow in the distal profusion cannula, no signals in the popliteal pedal arteries.

Sean Steenberge, MD:
And so she urgently was taken to the operating room with CT surgery and vascular, who converted her to VV ECMO. And we did perform the left lower extremity angiogram, which noted that the left SFA was occluded after removal of the SFA cannula, which was subsequently repaired open and then there was good flow distally. However, she did require four compartment fasciotomies, given the prolonged ischemia time. She was eventually decannulated from the ECMO two weeks later, however, given her prolonged acute limb ischemia, J was deemed to have a non-salvageable limb and, unfortunately, required a left above-the-knee amputation.

Sean Steenberge, MD:
So vascular complications can be very severe. Certainly we see them in situations like ECMO, where we have large arterial cannulas that are in place. These complications range from the limb ischemia, such as what we just saw, arterial dissections from access, pseudoaneurysms at the site of the access or retroperitoneal bleeds from high access sites.

Sean Steenberge, MD:
The important thing about this is that they affect patient survival to discharge, with about a 30% decrease in survival to discharge when they have vascular access complications. Things that increase the risk of these include large cannulas, female gender, usually due to their smaller arteries, young patients, and those with peripheral artery disease, which can complicate arterial access. However, most of these complications occur at the time of cannula placement, and that's why it's so crucial to make sure you have good arterial access at the initial procedure.

Sean Steenberge, MD:
In order to reduce limb ischemia, particularly in ECMO, distal profusion catheter should be placed and then systemic anticoagulation once the catheter is in place.

Sean Steenberge, MD:
However, this isn't limited to just ECMO. We see it in routine angiography. We see it in our TAVR population. This is a Canadian study where they reviewed their access complications, looking at those specifically and comparing those who underwent angiographic access versus ultrasound guided access. What they found is that for patients who underwent ultrasound-guided access, they had a statistically significant reduction in their major arterial bleeding, vascular arterial access complications, and life-threatening complications.

Sean Steenberge, MD:
So, how do we reduce the access complications? I think one of the best studies that demonstrates this is the Faou study, which was a multicenter randomized controlled trial that compared patients undergoing angiographic-guided arterial access versus ultrasound guided arterial access. When randomized one-to-one, they demonstrated that when you use an ultrasound, you have improved first-pass arterial access, you have a reduced median time to access, and then you also reduce risk of venipuncture and vascular complications, such as hematomas, pseudoaneurysms and retroperitoneal bleeds.

Sean Steenberge, MD:
The Vascular Surgery Group of New England then kind of looked at this further. They looked at all their arterial access for peripheral interventions over a course of several years, which included almost 7,500 cases of femoral artery access and demonstrated that when comparing ultrasound to angiography or just physical exam, they were able to reduce all their complications, including hematomas, when using ultrasound guided access.

Sean Steenberge, MD:
So we've kind of shown a little bit, again, the anatomy of the common femoral artery from the inguinal ligament down to the bifurcation. Our target zone is to try and puncture over the femoral head as this gives us a safe area to compress the artery when we remove our arterial access to get hemostasis.

Sean Steenberge, MD:
On ultrasound, this is an example, in Figure B here, of the bifurcation of the superficial femoral artery and profundus. And then C, you can see this is the common femoral artery. What's important to note is that we're able to ultrasound over the length of the common femoral artery and identify areas where there's not anterior plaque that might cause issues or dissection when trying to be punctured with a needle.

Sean Steenberge, MD:
Looking at the top, it's difficult to see the inguinal ligament on ultrasound at times, so it can be identified, and physical exam isn't always the best reliability. One thing you can use on ultrasound, as a tip, is that you can see here is the common femoral turning into the external iliac, the artery begins to dive down into the pelvis. In this 3D reconstruction of a CT angiogram demonstrates that as we cross into the pelvic brim and get over that bony prominence, the artery begins to die, and we lose our ability to compress and obtain hemostasis at this level, which is why it's so crucial to be able to access over an area of bony prominence.

Sean Steenberge, MD:
When we talk about ultrasound-guided access, we want to really target ultrasound-guided and not ultrasound localized femoral access. Certainly when you place an ultrasound over the artery, you can see when you put your needle in that there's some deformation of the tissue, but that's ultrasound localization. What we want is ultrasound-guided. What this means is that we select the area of where we're going to place our needle, hold the ultrasound steady, and then adjust our needle so that we can see the tip of it right over the top of the artery in the 12 o'clock position, and then watch it as it directly punctures into the artery.

Sean Steenberge, MD:
A good example of this is here seen in this ultrasound image, where you can see that we came straight in at the 12 o'clock angle, and you can see a hyperechoic density within the artery, which is the tip of the needle, demonstrating that we went through the anterior wall without getting into the posterior wall and have healthy access into the vessel. This can then be confirmed if you have access to fluoroscopy, demonstrating access over the femoral head. And you can see here, this is the tip of our needle right over the femoral head, which will allow us to get good compression after.

Sean Steenberge, MD:
I think in conclusion, ultrasound-guided access has been demonstrated in multiple studies to decrease vascular access site complications, and this holds true even from patients that have young, healthy arteries to those with very challenging anatomy. Fluoroscopic confirmation over a bony prominence is crucial as it allows us to get manual compression for hemostasis afterwards. Finally, the use of distal profusion catheters in VA ECMO can help decrease the risk of acute limb ischemia and major vascular complications from that. Thank you.

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