Sarang Mangalmurti, MD, an Interventional Cardiologist from Lankenau Heart Institute, Main Line Health talks about CAD therapy for heart disease.
Interview conducted by Ivanhoe Broadcast News in August 2019.
In this specific clinical trial, as they come in, this is sort of the precursor to inserting the stent. Talk a little bit about how far along they are.
MANGALMURTI: When someone has very advanced vascular disease and their calcium is severe, you can’t just put a balloon and stent in and be done with the procedure. You need to do something to almost clean out the inside of that vessel and clean out that plaque, which will facilitate the delivery of your balloon and then ultimately your stent. Traditionally, we would use drilling mechanisms for that purpose, but now we have technology that is very novel in its treatment approach. Instead of drilling out the vessel, we can use a special balloon that emits ultrasonic waves to crack or fracture all that calcium. You’re not creating particles that always run the risk of going downstream or causing a lot of trauma to the vessel. Instead, you can modify that plaque and weaken it. That will facilitate delivery of your balloon and then ultimately your stent in opening up that vessel.
Can you give us the layman’s analogy that you did before about the ice cracking?
MANGALMURTI: Nothing that we do in terms of angioplasty in the heart ever gets rid of plaque. All we’re really doing is sort of shifting that plaque to the side, or the wall of the vessel. Some plaque you can shift very easily, and those procedures are very fast. You put a stent in, and you’re done within a few minutes. But there are many vessels that have calcified plaque, so that if you try to put a balloon or try to put a stent in, you’re going to get a lot of resistance from that calcium that’s developed, and it’s hardened over years and years. It happens because people have diabetes and high blood pressure and cholesterol and smoking and all of that contributes to the hardening of these arteries and plaque over time. The shockwave technology allows us to fracture and weaken all of that plaque. We’re not trying to create it into smaller particles or shave it down. What we’re trying to do is create hundreds and hundreds of fractures along the course of that plaque so that it doesn’t create the kind of resistance that you would normally see. Then, when we put the balloon and the stent in, the stent can open up completely in that vessel because that plaque has become significantly weakened from the shockwave process.
Doctors have been doing this in kidneys and other organs for a while. When did this first come into being where you knew this might work?
MANGALMURTI: The original way to treat kidney stones is called lithotripsy. This is sort of the genesis of the idea. You can break up plaque inside of blood vessels using a similar mechanism. Now lithotripsy is administered from the outside of the body towards the inside, or the kidney stones. Here, what has been developed is a way to miniaturize the same principle onto a balloon. That balloon is introduced into the vessel. You’re treating the plaque from the inside of the vessel, not the outside. The idea is that when you advance your balloon into the vessel and inflate it, you can then activate these sonic pressure waves that will create waves of plaque modifying or plaque cracking forces. Normal tissue and normal vessel are unaffected by the ultrasonic waves. We know that from the early studies that were done using the technology. Once those studies showed a clear benefit, that the mechanism was working, it became widely available for use first in the peripheral vascular space so people can have atherosclerosis throughout their body. One very common area is in the blood flow to the legs. That’s what’s called peripheral artery disease. The very first access that we had to the technology was to break up plaque in the peripheral vascular space. Using that technology, we found exceptional results in vessels that were very complicated and traditionally not responding well to traditional angioplasty. Once we found that we were getting excellent results, then the technology was going towards the direction of other spaces to use. The coronary devices became available very recently. Presently they’re in the context of a clinical trial. With the results of that clinical trial, we expect and hope that the technology will then become widely available for general use the way it is in the peripheral vascular arena.
Can you walk us through as the balloon inflates, what conducts the shockwaves? And, how does it know to hit that calcium and not hit the vessel?
MANGALMURTI: The shockwaves are generated from emitters that are spaced out along the context of the balloon. Those emitters are connected to a generator. When we push the button on the balloon that generates the actual process where the emitter is sparked, that spark creates a shockwave pulse. That pulse is transmitted from the emitter out into the vessel wall. What controls what part of the vessel you’re treating is movement of the balloon and the emitters throughout the vessel. If there are certain areas that you want to treat with shockwave, you move the emitters and adjust them to that area. If there are other areas that you know do not have a lot of calcium in them and you don’t need to treat those, you don’t need to pulse in those areas. It’s really the operator who controls where the pulses are being administered in the vessel itself because you can see where those emitters are on your screen as you’re doing the procedure.
How much less invasive is this than the previous method?
MANGALMURTI: From the results we’re seeing after we do the treatment, there is significantly improved vessel compliance. That means the vessel has opened after the balloon angioplasty portion of it largely because we’ve fractured and weakened that calcification. Without treating the vessel with shockwave, what we oftentimes find is the vessel opens very quickly and that balloon will retract back to its original position because that calcification is still very strong. But with shockwave, we can see a big difference afterward just from the angioplasty. Ultimately the goal is to put a stent in and the stent delivery is far easier because the calcium is not fighting and resisting our efforts to deliver it and expand it to its full position.
From a technical aspect, how much healthier is Vicky after this procedure than she was when she came in?
MANGALMURTI: The goal is the same for her versus any other patient with coronary artery disease. If they have a severe blockage and we feel like they are having symptoms related to those blockages, then we want to fix those with stents. What we’re doing with this technology is facilitating that stent procedure. We’re enhancing the ability for the stent to not just be delivered into that blockage, but also to be opened in a way that you’re going to get the optimal results. If we can provide people the most optimal stent result, then in the long run that will be definitive and curative therapy for them. We know that one of the challenges in getting optimal stent results is this heavy plaque and heavy calcified disease that we encounter in blood vessels throughout the body, but particularly in the heart.
You talked about how you had to change and evolve to keep up with new technology. How do you feel as a physician and a person being able to help somebody with this groundbreaking technology?
MANGALMURTI: There’s no doubt that from a satisfaction standpoint as physicians who do these procedures day in and day out, it’s extremely rewarding. It’s the best thing that I can imagine doing for patients. What I find very rewarding about new technology like this is vessels that would otherwise be difficult to treat are now being made easier to treat with better results because of the application of technology. The satisfaction doesn’t just come from treating the blockage as much as it’s now allowing us to treat more and more people who have complex disease. That means that instead of sending these people for surgery, or in some cases maybe telling them there’s nothing we can do for you and you just have to live with your symptoms, we can now offer them very innovative technology and excellent results.
END OF INTERVIEW
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