UR Conducts First U.S. Study on Radiation To Reduce Failure after Leg Vessel Bypass
August 02, 1999
Physicians at Strong Memorial Hospital of the University of Rochester Medical Center are the first in the nation to study the benefits of external radiation on bypass grafting of the femoral artery in the leg. This noninvasive procedure may reduce post-bypass scarring and graft failure, reducing the probability of additional surgery and possibly saving lives due to fewer complications.
Called BIPASS (Benefits of External Irradiation for Peripheral Arterial Bypass), the FDA-approved Phase I/II study consists of 25 patients at Strong Memorial Hospital of the University of Rochester Medical Center, where the principal investigators are located, as well as from St. Joseph Medical Center in Albuquerque, N.M.
The study is overseen by principal investigator Philip Rubin, M.D., director of clinical investigations in the Department of Radiation Oncology; co-principal investigators Paul Okunieff, M.D., chair of the Department of Radiation Oncology, and Richard Green, M.D., chief of the Division of Vascular Surgery; with assistance from investigators Karl Illig, M.D., assistant professor of surgery, and Arvind Soni, M.D., assistant professor of radiation oncology.
Subjects involved in the study have undergone an arterial bypass of an obstructed artery in the leg. A graft - either prosthetic or the patient's own vein - is connected at either side of the blockage, which is bypassed to restore blood flow.
About one-third of patients who undergo arterial bypass eventually experience renarrowing, or intimal hyperplasia, at the connection between graft and artery, caused by surgical trauma. The body normally responds to the trauma by growing scar tissue to strengthen the connection between graft and artery, but the scar tissue often becomes excessive and narrows the vessel, once again making it difficult for blood to pass through. If this happens, patients may have to undergo repeat surgery to create a second bypass.
"With radiation, we hope to reduce scarring and, thus, the need for further surgical intervention relating to the new graft," Illig says.
The Phase I/II study considers the safety and effectiveness of radiation on grafts. As part of the study, subjects are given 10 external, low-level radiation treatments following surgery, one per day, to attempt to reduce the incidence of renarrowing and graft failure. Ten subjects have been enrolled to date.
"This safe procedure has the potential to save patients from having to undergo surgery a second time, and will possibly save lives in the long run by reducing the complications of intimal hyperplasia," Soni says.
Nearly 400 arterial bypass procedures are performed at Strong Memorial each year. About 100,000 are done annually in the United States. The cost for replacement of new grafts that have failed due to intimal hyperplasia exceeds $90 million in the U.S. each year.
The research team expects to ask the FDA for approval of a multi-institutional, randomized Phase III study that will include a greater number of subjects. The team has been conducting a concurrent large animal study of the radiation procedure to further support the findings in small animal studies.
Information about participation in the study is available by calling Dr. Philip Rubin or Leslie Koprowski, study coordinator, at (716) 275-5973.