Many providers have grown weary of offering the same old treatments – physical therapy, steroid injections – to their patients with knee OA, an increasingly prevalent condition that accounts for more than 80% of OA-related chronic pain and disability in the U.S. Fortunately, a new option has emerged: geniculate artery embolization (GAE), described in this talk by interventional radiologist Alexander Lam, MD. Hear and see how GAE works, view the data supporting its safety and efficacy, and find out which patients are the best candidates.
Hi, my name is Alex Lam. I'm one of the interventional radiologists here at U CS F. Uh Today we'll discuss genetic artery embolization, a novel intervention for knee pain uh from osteoarthritis, uh have no relevance disclosures. Uh The goals uh for today's lecture is to discuss the epidemiology of knee pain from osteoarthritis. We review the pathogenesis and rationale underlying gae for knee pain, uh briefly present the procedural steps, uh discuss the literature supporting GAE and provide some guidance on patient selection and adverse events after embolization. Uh Here is my outline. At first we'll get into uh a bit of background before we get started. Um So osteoarthritis is a leading cause of chronic pain and disability in the US. Do a accounts for more than 80% of the total disease burden and affects uh 19% of American adults. Uh 45 and older cos of me EEO A has doubled since the 20th century and is expected to increase as the population continues to age. Uh multiple options are presently available to manage pain including physical therapy. And instead as in joint injections, physical therapy hasn't proven to be quite effective. However, it can be logistically challenging to schedule and physically taxing uh for patients in, in some instances, joint injections uh provide excellent relief. It may last a few months uh and potentially can accelerate joint replacement. Uh In few studies. Gae is a novel procedure that complements the current treatment options. Next, I'll go into the pathogenesis and, and rationale. Uh and this, this slide is a little busy, this, this picture from glancing in 2019. Uh It's quite good, but again, it is a little, a little busy. I'll do my best to kind of parse it out into uh more digestible pieces. Um So I starts with some cartilage disruption from wear and tear that incites chondrocyte hypertrophy. Uh that does then lead to the generation of pro inflammatory mediators. And I've done my best to circle a few here on the image. Um chondrocyte function is then deregulated and synovial sites are activated that then leads to tissue hypertrophic, increased vascularity of circled uh VF or vascular growth factor in this slide. And that leads to the increase in in vascular vascularity uh within the within the joints and that'll play a role uh uh with respect to GAE. Um So this is more of a macroscopic view of the pathology that was published in rheumatology back in 2005. Uh This image from this image outlines the relationship between inflammation, angiogenesis and innervation. OK. Um All start with mechanical forces that lead to degenerative changes that then causes inflammation within the joints. Inflammation, angiogenesis and innervation are all highly uh integrated processes. Uh angiogenesis is typically accompanied by fine unmined nerves, particularly in the articular cartilage and the synovia and neo innervation may also further facilitate inflammation with the release of vasoactive peptides. Uh So what we have here is begin with inflammation that can stimulate angiogenesis, angiogenesis. Then in turn facilitates inflammation. Ok, angiogenesis also causes increase in nerve formation and that leads to uh further vessel formation through the release of the basal active neuropeptides. As we discussed, um pain in joints arises from the para articular soft tissues such as the synovium. But that periosteum and the joint capsule and is exacerbated by these abnormal neal vessels, vascularity. Gaegae includes these abnormal vessels um surrounding and applying the inflamed tissue. This limits the para articular inflammation and decreases the neo neo innervation resulting in decreased pain. Um So briefly go over the procedural steps. Um So it's an outpatient procedure with same day discharge. Uh and and moderate sedation is typically provided by our nurses. Uh and moderate sedation is sedation provided through an IV uh to help keep patients relaxed during the procedure. Just generally speaking, the ses um involved include obtaining access into the arterial system, performing an angiogram, which is essentially a picture that's obtained with our X ray. After we inject contrast directly to the artery, uh we can identify the pathologic flush, so to speak, which corresponds to the abnormal vessels. Uh We treat that territory with these particles uh called embolic agents. Uh And then we close the site that we created in the artery. Uh Typically with the plug. Uh The time it takes is approximately two hours for the procedure uh with about two hours of recovery um in our ir holding room. So here's a, here's an example um of a procedure that was recently performed. Um This is our initial angiogram. So, uh this is done through a catheter or a small tube that is uh within the femoral artery. Uh we inject dye and the contrast gives us a bird's eye view of the knee vascularity. OK. We also identify possible targets uh for treatment. I'll run this and enjoy our time and, and there's a still image on the right. And if I can direct your attention to the inner or the medial aspect of the knee, you can see these fine uh vessels that are surrounding the, the uh knee joints, we'll get better pictures in a little bit. Uh So we obtain more selective imaging and how we do this is by uh advancing an even smaller catheter into the genetic artery that is supplying that abnormal blush that we've identified earlier. Um And so we focus on, we focus on this area of blush by performing another angiogram and we can see it highlights the area that we're going to treat. We advance the small tube, the catheter deeper into the artery. Um And this is where we'll plan to treat. Ok. Here is our angiogram. Uh And what we can see is we can see that fine network of vessels that is wrapping around uh the inner aspect of the knee joints from here, this is where we're going to treat. So we then proceed to inject small plastic beads again, 100 to 300 microns in size but quite small uh under live x-ray or fluoroscopy to prune the abnormal arteries. Uh After we treat uh by injecting the small beads, we repeat the Angra. Um And what we're looking for are two things. One, we wanna make sure that we don't have um those abnormal vessels that blush that we discussed, but also wanna make sure that we have uh persistent flow into the knee joints. So we wanna make sure that we still have uh flow. And so what we see here um there's still image on the right, we still see the chunks, so to speak. Um But the leaves have been have been pruned. OK. After this is done, we proceed to close the hole in the artery that we've created again with a small plug that dissolves completely on itself. Uh Here, just the before and after images uh before embolization, we see that fine lace like um blush. And after emal organization, we just see the, just see the branches, so go over some outcomes and risks. Uh safety and efficacy has been shown in multiple studies. Acuna was the first to publish his experience on genetic artery embolization and he found an 86% rate of clinical success at six months and 72 patients. And clinical success was determined to be a 50% or more uh decrease in pain. A A was the first to publish his results uh and results in the US specifically. Uh and this is a significant decrease in the visual analog score from 76 to 30 in 20 patients. Uh And little was the first to publish his results of looking at patients in the UK. And, and uh this group found a significant improvement in the visual analog score from 60 to 36 and 38 patients. Um More recently in, in 2022 it was a uh a multi center trial comparing gae to sham procedure. And the doctors found that there was a significant uh significant improvements in pain and disability in the patients who were treated with uh embolization compared to those who received the sham procedure. And a me analysis of 10 studies which included 351 knees found a significant decrease in pain scores at 136 and 1212 months. Uh Some studies results have shown that uh the pain improvement have persisted up to two years, uh which is quite remarkable uh in my experience in general, about 60 80% of patients derive significant pain relief from the procedure. The risks are overall quite minimal. Ok. Uh No major adverse events were found in multiple studies. Uh There were a few minor adverse events which include access at hematomas or just blood bruises around the area that we access, uh need discomfort uh following the procedure that can last a few days. Uh and skin discoloration, which is actually relatively common. Ok. In earlier studies, it's seen in up to 65% of patients. Uh and it's typically transient with newer techniques, Neer embolic uh that number has been reduced to about 20% but still present uh and not, not uncommon. Um And in, in a cuno uh in this study published in 2017, found there has been no evidence of bone necrosis, cartilage loss, li ligament rupture or muscle atrophy. In 2129 patients who received an M ria follow up. Uh And there is limited data that suggest that post analyzation uh knee replacements are safe. Um Neuro studies suggest that there is improvement in chronic pain um in patients who uh have received uh prior knee replacements uh treated with gie um which is again a a pretty promising indication for this procedure. Um So, in terms of patient selection, who are the ideal uh genetic artem as candidates. Um So patients with mild to moderate O A on a need or radiograph are, are, are the ideal uh patients um gae can be performed in patients with more severe knee O A. However, the pain relief is less or, uh, and some studies have found that you get relief up to six months, but then after six months that pain relief, uh, pretty much becomes insignificant. Uh, patients at high surgical risk are good gae candidates. Um, because gae is performed with moderate sedation. Ok. And sometimes even, uh, local anesthesia, uh, if necessary, you know, as compared to uh a larger surgery where anesthesia is, is required, uh, patients would like to avoid or delay surgery. Um This is also a good option. Um because gae again has been found to uh result in durable pain relief for up to two years, uh which is a significant amount of time. Ok. And for patients who have exhausted more traditional options such as physical therapy, joint injections and weight loss and nsaids, et cetera, this is a good option. I really because it's, it's, uh, treats me pain in a different fashion and the new fashion that's separate from uh these separate um, uh modalities um and can potentially complement the, these other interventions. Um So we'll go over to a quick summary as well as logistics. Um, gae is a novel procedure for managing knee pain from osteoarthritis with a growing body of evidence, uh, showing safety and efficacy, uh, procedures performed as an outpatient, uh and well tolerated. It's a great alternative for patients who have tried uh more traditional non surgical interventions. Uh And for those who would like to avoid surgery, one reason or another. Uh in terms of logistics, all patients who referred to, to, to U CS Fir for genetic RD embolization are seen in clinic uh before and after the procedure in clinic. Um in clinic, patients are given the opportunity to discuss this procedure further the risks, benefits and alternatives following the visits. If the patient would like to proceed, uh The IR staff will manage the additional work up that may be needed if any as work as well as work on the insurance uh coverage. Uh Part of it at U CS F. There are multiple specialists including orthopedic surgery and pain management to name a few who are available to discuss the alternatives to gie if, if that's not the road that they want to pursue. Um just, just briefly. So here's some contact information. If there's any interest, feel free to call this number to uh U CS F interventional radiology. Um I have a website here uh for more information and of course, there is my name. Um And for those refers who would like to place a referral, you can place an ma referral to IR once my staff receives a referral, they'll take care of the rest. Uh Here, the references that I'm happy to share. Uh Otherwise, thank you so much for your attention.
