Drug-coated Balloon for PAD
Interview | Drug-coated balloons (DCB) have shown potential in improving results for patients with peripheral artery disease. CardioSource WorldNews had the opportunity to speak with John Laird, MD, FACC, cardiologist, and medical director of UC Davis Vascular Center, Sacramento, CA, about the IN.PACT Admiral Drug-Coated Balloon for treating patients with peripheral artery disease in the superficial femoral and the popliteal artery.
CardioSource WorldNews: You were one of the investigators of IN.PACT SFA trial, published in Circulation this year. Tell us about the drug-coated balloon.
John Laird, MD: The trial focuses on a paclitaxel-eluting balloon that we tested, in this trial in a randomized fashion, against standard balloon angioplasty for stenosis and occlusions in the SFA and proximal popliteal artery. Three-hundred and thirty-one patients were randomized in the trial, two to one between the drug-coated balloon and standard angioplasty. What we found was that, at 12 months, primary patency was dramatically better in the patients treated with the drug-coated balloon, 82% primary patency compared to 52% with standard balloon angioplasty; most remarkably, the need for target lesion revascularization or additional procedures was incredibly low—only 2.4% with drug-coated balloon compared to 20% with standard balloon angioplasty. So because of the very favorable results of the trial, ultimately the FDA to approved the IN.PACT Admiral balloon for use in patients in the U.S.
Regarding the mechanisms of how the DCB works, it leaves some coating behind. Is that what helps keep an opening?
All the balloons are a little bit different in terms of how they work, but the primary mechanism is that the balloon is coated with paclitaxel and a carrier molecule (or excipient), which basically allows the drug to come off the balloon and be delivered into the vessel wall where it sticks around long enough to have an impact on neointimal proliferation. For example, with the Medtronic balloon, the excipient is a compound called urea, which is combined with the paclitaxel. The balloon is coated 3.5 micrograms per millimeter squared dose. When the balloon is inflated in the artery, the drug comes off the balloon, is taken up into the vessel wall, and sticks around for at least 2 months, long enough to have an impact. Paclitaxel seems well suited for this type of approach because it’s lipophilic, and it’s well absorbed into the plaque in the vessel wall.
In the last few years, some drug-eluting stents have also been evaluated in trials, so there are several different options, including the balloon. Is there any indication in terms of which is the better choice?
A drug-eluting stent and a drug-coated balloon haven’t been compared head to head, yet. There was a small trial done in Europe, which I think just recently completed enrollment; so within the next year or so we may get some idea of which is better, the stent or drug-coated balloon. For now, I think it’s a little bit up to the operator and their preference and the lesion type. I think there are those who favor the approach of leaving nothing behind or leaving no metal in the SFA, so they like the idea of a drug-coated balloon—and then only placing a stent if there’s a really suboptimal result with that drug-coated balloon.
Why has it taken so long for drug-eluting stents to start being used in the setting of the peripheral arteries?
Well, it turned out to be not as simple as people thought it would be. Companies—Cordis Corporation and Abbott, for example—attempted to make a drug-eluting stent using basically the same drug and the same polymer technology that they used in their coronary drug-eluting stents. I think they expected that it would work. And at 6 months there was a favorable outcome with regards to restenosis with a drug-eluting stent compared to the bare stent; by a year and beyond, that benefit was lost. So there’s something about the SFA. Maybe it’s the plaque burden, or maybe it’s the mechanical forces at play that make it a little bit more complicated. There’s really only been one drug-eluting stent that has, so far been shown to be effective, and that’s a paclitaxel-eluting stent. And there’s really only one drug-eluting stent that’s approved in the U.S. for clinical use.
It’s a fascinating field; are you finding that there is more attention being paid to the peripherals in cardiology meetings?
Yes, absolutely. I think it’s important for cardiologists to be involved in the treatment of patients with peripheral artery disease. A good percentage of our patients have concomitant peripheral artery disease. There’s a very important need for better medical therapies for people with peripheral artery disease to reduce their risk of heart attack, stroke, and premature death, as well as a need for ways to improve their quality of life—to allow them to walk better and further, and to feel better.
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