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Transcripts: 543.2 to 543.4
Week: 543.2 Guest: Dr. Charles, Chambers, Assoc. Prof. Med. & Radiology, Penn State and Director of Cardiac Cauterization labs, Milton S. Hershey Medical Center Topic: Angioplasty and the future of the procedure, Part One of Three Producer/Host: Steve Girard
NEMA: We're going to take a look at the state of balloon angioplasty, a relatively new procedure that has risen to prominence in a surgeon's toolbox, both treatment and prevention...and continues to get better. Dr. Charles Chambers, director of the cardiac catheterization labs at Penn State's Hershey Medical Center, is with us today....
CHAMBERS: Percutaneuous transluminal cauterangioplasty, called PTCA, and referred to as balloon angioplasty was first done in 1977 in humans by Andreas Scrunzik at Emory University in Atlanta. Since that time, now over the past 20 years, balloon angioplasty has not only changed tremendously with respect to equipment, as well as operator experience, but also newer technologies for taking care of the athroscoratic plaque, the hardening of the arteries.
NEMA: What have been the major changes in the procedure?
CHAMBERS: Certainly, as with any technology, equipment that we use with interventional cardiology, with balloon angioplasty, has changed. The wires which have to be put down the coronary artery, across the blockage, are about 14 thousandths of an inch in size. The balloon catheters, which have to be placed across the blockage and then blown up, have gotten smaller and smaller with time. So now, it's the rare blockage in the coronary artery that we can't put a balloon across. But besides just the balloons, we now have other techniques to take care of plaque or blockages, or hardening of the arteries within the coronary system. And there are basically five other techniques besides the balloon itself that are used oftentimes with balloons, but are used to treat these blockages.
NEMA: Okay, let's take them one by one....
CHAMBERS: The ones that are currently available are called rotobladder, rotational anthrectomy...is composed of a nickel burr that's diamond chip coated and rotates at 200 thousand revolutions per minute...and kind of roto-rooters the blockage. Kind of emulsifies the particles, and then they go distally through the coronary bed. The, what we call the directional coronary anthrectomy, referred to as the cutter, has a balloon on one side, and an open chamber on the other, and the blockage is pushed into this open chamber, and then cut out and removed from the system. Transluminal extraction athrectomy, the tech catheter, is kind of the hoover vacuum cleaner of interventional cardiology, used more for old, saphinous vein graphs, or really clotty arteries. That's an instance where you go in and kind of suck out the blockage. Lasers, the laser catheter, the xenon-chloride laser...photochemically ablates the lesion. The interventional device that has changed interventional cardiology, that has advanced balloon angioplasty probably the farthest is what we call stents. A stent is made up of multiple types of wire...and they're like a scaffold, that are placed on a balloon and pushed into the coronary bed, keeping the artery open, and oftentimes decreasing the incidence of this artery re-narrowing overtime. And those are the advances we've seen. And I think what's changed interventional cardiology the most is the stents, that open the coronary artery, keep it open, and decrease this recurrence rate, which in balloon angioplasty may be as high as one in three.
NEMA: Dr. Charles Chambers of the Penn State Hershey Medical Center. We'll talk about new advances in interventional cardiology in our next program. I'm Steve Girard.
Week: 543.3 Guest: Dr. Charles, Chambers, Assoc. Prof. Med. & Radiology, Penn State and Director of Cardiac Cauterization labs, Milton S. Hershey Medical Center Topic: Future improvements in balloon angioplasty, Part Two of Three Producer/Host: Steve Girard
NEMA: Dr. Charles Chambers, the director of cardiac catheterization labs at Penn State Hershey Medical Center, has been talking with us on the field of interventional cardiology, especially balloon angioplasty to remove blockages in coronary arteries. Doctor, what new techniques are on the horizon?
CHAMBERS: There's three technologies in particular that I think we'll see more of, or at least will be worked on more over the next several years...and hopefully available, or some component will be available for the next millennium. The first one is called the angio-jet thrombotic catheter...and basically what it has is six jets within the tip of the catheter, that pulse water at about 2,500 pounds per square inch. Deliver this poultitile jet to blast the blockage out, and have that emulsified again circulate distillent to the circulation. But the key are these high pressure jets, which emulsify the particle and then have them sucked back into the catheter. Another technology which is I think very novel, is called the cutting balloon. And what it is composed of is either three or four longitudinal cutting blades inserted onto a balloon catheter...such that when the balloon inflates, these tiny, little micro-surgical incisions are made such that when the artery is expanded, it expands throughout its course, and not just as it would in the routine balloon, not just at the point of least resistance...these small little incisions allow the balloon to fully expand throughout its course as a uniform artery dilation...uniform artery opening. What we're also going to see, or at least have the potential to see, is a fancy term called intervascular brakey therapy. And all that means is actually locally delivered radiation therapy within the coronary arteries. It may even be radiation on a stent, where a stent would be put in a coronary artery with the tiniest amount of radiation on it. Inside your artery, with the thought that this little bit of radiation will decrease the repair process within the artery after the procedure, and decrease the likelihood of it coming back.
NEMA: And there may be better ways to combine other treatments as part of the process...?
CHAMBERS: There may be some additional advances in local delivery in balloon catheters...catheters that have little holes in them, that deliver medication right at the site.
NEMA: Are there some medications that work best with this approach...?
CHAMBERS: There's a lot of medications out there that people are looking at for local delivery...whether it be radiation, whether it be certain medications...the key to the local delivery system is the amount of medicine you have to give through a balloon locally at the site is maybe just a tiny bit, but if you give it as a pill, to affect the whole system, it's a huge amount. So, if you can deliver any of these medicines right locally, at the site, with the new devices, that's what's really exciting.
NEMA: Dr. Charles Chambers will return with us to discuss the choice between balloon angioplasty and open heart surgery... in our next program. I'm Steve Girard.
Week: 543.4 Guest: Dr. Charles, Chambers, Assoc. Prof. Med. & Radiology, Penn State and Director of Cardiac Cauterization labs, Milton S. Hershey Medical Center Topic: Angioplasty- treatment and a comparison to open heart surgery, Part Three of Three Producer/Host: Steve Girard
NEMA: We've been spending time with Dr. Charles Chambers, associate professor of radiology at Penn State, and the director of the cardiac catheterization labs at the Milton S. Hershey Medical Center in Pennsylvania. Has balloon angioplasty, a form of preventive cardiology using a wire and a tiny inflatable balloon to help clear blocked arteries, become more and more prevalent today?
CHAMBERS: Well, it's kind of interesting, when balloon first started, several things limited it, but in the initial studies, between 1977 and...well, actually it started in the late 70's to early 80's..over a three or four year period there were like three thousand patients entered into a study. Now, balloon angioplasty - statistics I saw from 1991, were 300 thousand ...and from 1995, up over 400 thousand - upwards of 450 thousand coronary interventions done every year, whether it be balloons or stents or rotobladders...these things we deal with in the coronary bed have really expanded.
NEMA: Why are the numbers going up?
CHAMBERS: What I think has expanded the use is the safety of the procedure. Whereas in the early days of balloon angioplasty, upwards of five to even ten percent of people may go emergently from an angioplasty that went wrong, to open heart surgery. The way the balloon works is it pushes the blockage into the arterial wall, and sometimes it actually cracks the artery and closes the artery down, and the only thing you can do to fix it is send them emergently to surgery. Now, with improvement in technology, with stents, the likelihood of going emergently for surgery is certainly less than two percent, and down around one percent. The use of the procedure, and the effectiveness of the procedure, I think have gone hand in hand. People that you may in the past have just gone with medicines, rather than take the chance of a coronary intervention...now we tend to go with coronary interventions and hopefully cut down on the use of medicines.
NEMA: Doctor, we talked about stents a little earlier, you told us they are tiny wire constructs that are used to kind of brace arterial walls during the balloon angioplasty process...now, when should people have bypass surgery as opposed to a balloon angioplasty?
CHAMBERS: We often times would do balloon angioplasty for one artery and most commonly, two arteries blocked. When someone has multiple arteries blocked, we think more commonly of surgery. Recently, there's been studies that have looked at comparing open heart surgery to balloon angioplasty, and in those studies, we see balloon angioplasty and open heart surgery having similar results...certainly with respect to mortality. But the key to all this, whether you have open heart surgery, or whether you have balloon is....you have to look at whatever intervention is done to your heart, it's to make you better for the moment, but it's essential that regular exercise, cholesterol control, stopping smoking, those things have to be taken care of by the patient. So, what we do to take care of the problem at the moment, is, long-term, dependent upon the patient to take care of our work.
NEMA: Balloon angioplasty has become a lifesaver over the last 20 years, and a mainstay for surgeons who are trying to use less invasive methods of interventional cardiology that will save a life, decrease the recovery time, and improve the resulting quality of life. Our thanks to Dr. Charles Chambers of the Penn State Hershey Medical Center. As always, if you have questions, your first source could be your doctor...or perhaps to the National Institute's of Health's Internet Grateful Med program. I'm Steve Girard.
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