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Release: Sept. 4, 2002

UI Heart Care researchers studying advanced treatment for narrowed bypass grafts

University of Iowa Heart Care researchers are studying a new, fabric-covered stent in the treatment of patients who have developed a narrowing in their cardiac bypass grafts.

The advanced device, called the Symbiot stent, is covered with a special fabric that may help prevent the narrowings in the vein grafts that are used to bypass blockages in the arteries of the heart. A stent is placed in an artery or vein to help the blood vessel to remain open after a narrowing has been corrected during a balloon angioplasty procedure.

"A stent is basically an expandable metal tube that looks like a scaffold, and tissue can grow between the gaps in the scaffold and cause the bypass graft to become narrow again," explained James Rossen, M.D., a UI associate professor of internal medicine, a cardiologist and director of the Cardiac Catheterization Laboratory and Interventional Cardiology at UI Hospitals and Clinics. "We hope that by covering those gaps with this special fabric that we can prevent this re-growth of tissue and avoid the development of another narrowing."

The fabric-covered stent may also help reduce the incidence of a common complication where bits of tissue break off from the repaired part of the bypass graft and float "downstream" and cause blockages elsewhere in the heart.

Heart surgeons perform a cardiac bypass graft by identifying the location of a blockage in cardiac artery, removing a vein from another part of the body such as the leg, and then attaching the vein to the artery in order to route the flow around the blockage and restore a more normal blood supply to the heart. The procedure is very common and effective, but about one-quarter of such bypasses can become narrowed. Balloon angioplasty is effective is removing the narrowing, and conventional stents can also achieve good results.

The University of Iowa research team will enroll up to 30 patients with a narrowing in their bypass grafts into the randomized clinical trial. For more information, contact Rossen at (319) 356-3413.

University of Iowa Health Care describes the partnership between the University of Iowa Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at