Michael Chan, MD, Interventional Cardiologist at St. Joseph Hospital/Orange, CA, talks about the bioabsorbable stent as compared to traditional metal stents.
Interview conducted by Ivanhoe Broadcast News in August 2017.
Let’s talk a little bit about the absorbable stent, how is it different than your traditional stents?
Dr. Chan: The new bioabsorbable stents that were approved last July are a game changer for us. Because it allows us to have a stent is implanted in the heart vessels that will serve its function and eventually dissolve over the course of two to three years. Whereas, older stents, the metal stents, stay in place in the body for its lifetime.
What was the benefit of it being absorbed in the body?
Dr. Chan: The stent, this absorbable stent technology which we’ve been working on for a couple of decades now is something that is attractive for both our doctors and patients. Patients often times ask, will the stents stay in my body lifelong? And they worry about that. I think the benefit of something that dissolves after its purpose has been used is really attractive for patients. For doctors the benefits here are theoretically workable. It does serve its purpose for the first year or so that we need it and then eventually resolves. It allows us theoretically to have less inflammation because of that and also it reduces that risk of clot formation that can form later on in stents because of the metal exposure.
What is it made of that it can dissolve?
Dr. Chan: Its polylactate or it’s a compound similar to absorbable sutures; it’s the same kind of compound that we see there. So that allows this to absorb over time.
It was approved July of 2017 is that right?
Dr. Chan: It was July 5th of 2016.
I know there has been a little bit of controversy over them saying that there’s a slightly higher chance of heart attack or replacement?
Dr. Chan: Yeah, this is the first generation of the stent so the technology and the concept are amazing to us. But as a first generation stent it’s going to have some refinement over time. If it’s not used in the proper setting, that makes the risks higher. We’ve seen that in smaller vessels, that heart attack risk as you mentioned, and risks of clotting are higher. So they recommend avoiding smaller vessels and very long areas. Mostly areas with a lot of high calcium in them we tend to avoid as well. I think it’s at this point used in a subset of patients that are selectively chosen but overall in those subsets it seems to perform comparable to the current stents.
Who is a good candidate for this?
Dr. Chan: Patients that would benefit from this, for example, maybe somebody who may need bypass surgery down the line. Because whenever we put a metal stent in place, if the surgeons need a bypass into that territory and there’s a stent already in the artery, they won’t be able to bypass it. So it may allow us to safely stent that artery to be bypassed later as an option. Other patients that are generally more targeted are certain vessel sizes, we avoids a lot of calcium, some younger patients where you can avoid a lot of metal in them or long term metal. Those are some of the subsets of patients that we consider.
So who wouldn’t be a candidate?
Dr. Chan: Patients we want to avoid are patients with very small vessels, very long blockages where we have to use a lot of them because the FDA approval is for about twenty four millimeters or two and a half centimeters in size. So we want to avoid those kinds of situations. Those are probably our big ones.
Let’s talk about more benefits.
Dr. Chan: Other potential benefits here for this technology can include pediatric applications. In children for instance, where they continue to grow. If they want to try to fix a narrowing of an artery, something like the aorta that can narrow; we call it coarctation, if that narrows traditionally they try to open that with balloons. They would love to put a stent in but because children grow that stent will be too small for them as they age. So something that absorbs over time will theoretically be very beneficial. That’s another area where it would be very helpful for them.
It won’t completely replace the traditional stent because of all the issues that you were talking about before?
Dr. Chan: Yeah. Currently, in the summer journals of 2017, right now it’s not going to be widely used. I think it’s going to be a subset of patients that would be benefitted from this, but not something that we would use across the board for every patient. But as technology evolves there are many in our field that feel like this will be the next generation.
What haven’t I asked you that you think we should get across about the disposable stent?
Dr. Chan: I think you’ve covered most of the main issues here. The technology is very, very attractive for us. But again it’s early first generation, I think there’s going to be continued refinement of this technology over time. We’re looking forward to the refinement. There are a lot of companies right now working on this and I think we’ll see better innervations as we go down the line.
Let’s talk about Charles. What was his situation?
Dr. Chan: Charles came in with what we describe as unstable angina. He was having chest pains and fast heart rate during dialysis and so had a small heart attack in that setting. There was a tight narrowing in the beginning of his artery down the front of the heart. That’s what caused the LAD or left anterior descending, the major artery supply to about half the heart muscle. Because of that location and a short area we thought an absorbable stent would be beneficial. He’s had prior stents in other areas there so we want to try to avoid additional long term metal in there if we could.
How long ago did you put in his?
Dr. Chan: His was placed in about three weeks ago.
END OF INTERVIEW
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