So, I changed the title a little bit, Imaging-Guided No-Contrast Arterial PBI. So, I'm going to start with a case I know most of us don't look at foot x-rays very much, so I highlighted it with a circle. There's evidence of osteomyelitis in this gentleman's right third toe with involvement of the ray as well. And you can see on his ABI-TBI, this is actually after he had already underwent intervention at an outside hospital of his SFA-popliteal artery, his ABI remained a little bit low, 0.8, normal being 1, and the toe brachial index was 0.36, with normal being about 0.6 to 0.7. And you can even see by the waveforms in the bidephemeral head that it's a little bit dampened, it's a biphasic waveform. So, we thought that he needed a better understanding. However, his creatinine is high, and now it's even higher, it's 4 by the time that I see him in the hospital. So, I started out with a noninvasive ultrasound first, a different kind of ultrasound. If you're doing endovascular, if you're thinking about dabbling in endovascular, I would urge you to learn your noninvasive studies so you can understand what you're looking at. And this is an acceleration of the velocities within the patient's external iliac artery, suggesting that perhaps there was a lesion here that was missed on the first angiogram, and perhaps they were trying to perform more contrast-steering methods, and hence maybe missed this lesion. So, we took the patient to the cath lab, performed CO2 angiography. So, when you perform CO2 angiography, the vessel actually then looks white rather than the traditional black, and I'm sorry, I don't know why these are not playing. But you can see there's actually a lesion right here in the external iliac, it's a little bit tapered. So, not super obvious, and then in the tibial, surprisingly, you can actually see a tremendous amount. This is the tibial peroneal trunk, peroneal and posterior tibial arteries. The anterior tibial artery is occluded, but there's actually fillings via the posterior tibial artery, and it reconstitutes the dorsalis pedis as well. This is all with CO2 contrast, no iodinated contrast is utilized at all. So, I performed the ivis of the iliac lesion, this was an 018 ivis, and here you can see, I'm going to highlight a couple of areas here where there's a really eccentric soft plaque, and there's a little bit of eccentric calcium as well. I measured the mass diameter reference to be about 6.6. So, I did go ahead and do a self-expanding stent. Unfortunately, he starts to breathe as I was taking this angiogram. Nonetheless, we performed a finishing ivis, which confirmed there's a decent stent expansion as well as edge position as well. Importantly, using our hemodynamics as we're cardiologists at the heart of it, his initial systolic gradient was 70, and it did drop to essentially 0. That was the first case. Second case, I'm sorry to be showing this picture in the middle of lunch, this is a patient who's had this wound actually on and off for several years. Now, if you do a lot of vascular procedures, you'll notice this wound is a little bit of a mixed morphology. It's not just arterio and source. It's a little bit of venous congestion as well. You can see a little bit of bogginess within the foot, and probably a little neuropathic as well. This patient, as you can see by the ABI, actually has a prior BKA on the other side, so it's very important for us to salvage this leg. Also importantly, all of his arteries are non-compressible, so we can't really tell much based on the ABI. We had to take him to the cath lab, and he also had ESRD, or close to ESRD, but not yet on dialysis. So we performed an angiogram, and you can notice here there might be some disease here on the CO2. If you're kind of like me, when you first start doing CO2 angiography, at the end of it you feel like you need an angiography. So what I did, this is some post-processing. I actually reversed the color on the Siemens machine, so you can appreciate then in a more traditional view that there are actually very subtle but moderate lesions throughout his SFA papal teal artery. On the ibis, we can see that there's chunks of calcium just throughout here. And again, like Dr. Parikh mentioned, we don't really have a classification system as robust as we would in the coronaries, at least not yet. So yes, there's calcium. We think we have to modify it. We think we have to intervene. There is a gradient of about 30 millimeters of mercury systolic between before and after the lesion, so poor woman's FFR, if you will. We placed a filter, performed atherectomy with CSI, a drug-coated balloon was placed, and afterwards you can see decent expansion. And perhaps this is something we can discuss as a panel. Unlike the coronaries, we actually try not to stent in general in the lower extremities. You can imagine when the patient is moving or something happens to their leg, the stent can get fractured. So in general, we try not to stent, but there's still lesions that are there. But, you know, there's still lesions. There's still calcium there. And when is the point to stop? And how do you say, no, I'm not going to stent this? I think that's a lot that we have to learn in terms of IVUS and its application in peripheral. His wound did start to get better. This is the podiatry note. You can see the reduction in volume. And just to highlight a little bit on CO2 angiography, feasible even in the tibials and foot does require some adjustment, as you can see. Typically, I use 20 cc of CO2 injected per picture. Don't use in any arteries above the diaphragm. Very important. And here's a reference from Jay Mohan regarding how to use CO2 angiography. And perfecting a low contrast injection. So during that contrast shortage that we had last year, what we really learned is that you can do a lot of these peripheral angiograms with minimal contrast. So what we do is we prefill the syringe with saline, and then we do a 2 cc fill of contrast. Essentially, you inject bolus and chase. So I can do five pictures with only 10 cc of contrast in one patient. Typically, for a diagnostic plus intervention, I can get away with 30 to 35 cc of contrast. So same concepts can be applied for renals as well, typically about 1 cc per renal. So feasible, even with tibials. Ensure that you're parking the catheter as close as you can for a more selective injection. If your SFA is occluded to visualize the tibials, you may want to park your catheter in the profunda. Garner the power of intravascular imaging in these cases. And hemodynamics are vital. Thank you.

physician

peripheral arterial disease

ultrasound

CO2 angiography

lesions