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NEW NON-SURGICAL TECHNIQUE ZAPS BUILD-UP IN ARTERIES
ORLANDO, Fla. -- A new therapy called photoangioplasty appears to dissolve plaque buildup in blood vessels and holds promise as a treatment for arteries that have reclogged after angioplasty -- a procedure performed hundreds of thousands of times annually in the United States. Research on the new therapy was presented here today at the 24th Annual Scientific Meeting of the Society of Cardiovascular & Interventional Radiology (SCVIR).
As a Phase II, multicenter trial of the light-activated drug lutetium texaphyrin (ANTRIN(tm)) gets under way, early research indicates it may be useful in combating a variety of artery-blockage problems. The drug is delivered intravenously and activated 24 hours later using an interventional radiological technique that threads an optical fiber under imaging guidance into the narrowed blood vessel.
"This drug also may play a significant role in restenosis, a very troublesome problem in which blood vessels reclog after angioplasty," said Mahmood Razavi, M.D., assistant professor of radiology, division of cardiovascular and interventional radiology, Stanford University Medical Center, Stanford, Calif. "It also may become a primary treatment in combating plaque build-up, or atherosclerosis."
In the Phase I portion of the trial at Stanford, of 14 patients with clogged leg arteries treated with photoangioplasty and evaluated by angiogram (X-rays of the blood vessels) and ultrasound, 11 patients showed a 10 percent to 74 percent reduction in atherosclerotic plaque.
Because the optical fiber is only a few inches long, it would be difficult to treat long portions of clogged leg arteries, said Dr. Razavi. He therefore believes photoangioplasty is more likely to be a potential therapy to treat atherosclerosis in the smaller heart vessels. However, animal studies also have shown photoangioplasty to be effective in treating restenosis, and therefore may have a role in treating the problem in leg blood vessels, said Dr. Razavi. Restenosis, or scarring of the inside of blood vessels, is a stubborn problem that often occurs after angioplasty. After angioplasty, restenosis develops 30 percent to 50 percent of the time in coronary, pelvic and thigh arteries, and more often in arteries below the knees.
A Phase II multicenter trial is planned for later this year to explore the use of photoangioplasty in leg arteries as a treatment for plaque, as well as a therapy for restenosis.
A trial to assess the effects of photoangioplasty in the coronary arteries is scheduled to begin later this year.
Currently, atherosclerosis is treated with medical therapy, surgery or nonsurgical procedures such as balloon angioplasty. There are approximately 600,000 coronary angioplasty procedures performed annually, and another 150,000 such procedures performed each year in the legs.
Co-authors of a paper on the topic being presented by Dr. Razavi are: Stanley Rockson, M.D.; Andre Szuba, M.D.; Shuja Yousef, M.D.; John Cooke, M.D.; Michael Dake, M.D.; and Dan Adelman, M.D.
An estimated 5,000 people are attending the Annual Scientific Meeting in Orlando, Fla., of SCVIR, a professional society based in Fairfax, Va., for physicians who specialize in minimally invasive interventional procedures.
An interventional radiologist is a physician who has special training to diagnose and treat illness using miniature tools and imaging guidance. Typically, the interventional radiologist performs procedures through a very small nick in the skin, about the size of a pencil tip. - more - Interventional radiology treatments are generally easier for the patient than surgery because they involve no surgical incisions, less pain and shorter hospital stays.
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Copies of 1999 SCVIR news releases are available online at www.pcipr.com/scvir beginning Monday, March 22.
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