Pretreating a vein graft with edifoligide prior to coronary bypass graft surgery does not lower the rate of graft failure, according to a study in the November 16 issue of JAMA: The Journal of the American Medical Association.
This study is being released early to coincide with its presentation at the American Heart Association's annual meeting.
Coronary artery bypass graft (CABG) surgery is one of the most common surgical procedures performed in the United States, according to background information in the article. In appropriately selected patients, CABG surgery results in improved survival, relief of angina, and improved quality of life. Despite frequent use of artery grafts, vein grafts remain the most frequently used conduit. The long-term patency (duration of remaining open) of vein grafts is limited and graft failure has consequences similar to those of coronary artery disease: recurrent angina, myocardial infarction (MI), additional revascularization procedures, and premature death.
Neointimal hyperplasia (abnormal increase in the cells lining the inner wall of the blood vessel) leading to accelerated atherosclerosis and thrombosis is one proposed mechanism of vein graft failure. Neointimal hyperplasia begins as an adaptive response to the increased pressure and shear forces of arterial circulation. A new approach to inhibiting neointimal hyperplasia and preventing graft failure involves using edifoligide, which was developed to work via gene therapy to inhibit cell proliferation. For this study, researchers took each patient's harvested vein (that would be used for the graft) prior to CABG and treated the vein for 10 minutes with a pressure-mediated delivery system with either edifoligide or saline placebo.
John H. Alexander, M.D., M.S., of Duke University Medical Center, Durham, N.C., and colleagues conducted the Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT IV) trial to assess the efficacy of edifoligide in preventing angiographic vein graft failure. The study included 3,014 patients undergoing primary CABG surgery with at least 2 planned vein grafts. The first 2,400 patients enrolled were scheduled for 12- to 18-month follow-up angiography. The patients were enrolled in the study between August 2002 and October 2003 at 107 U.S. sites.
A total of 1,920 patients (80 percent) either died (n=91) or underwent follow-up angiography (n=1,829). The researchers found that edifoligide had no effect on the primary end point of per patient vein graft failure (436 [45.2 percent] of 965 patients in the edifoligide group vs. 442 [46.3 percent] of 955 patients in the placebo group; or on any secondary angiographic end point, or on the incidence of major adverse cardiac events at 1 year (101 [6.7 percent] of 1,508 patients in the edifoligide group vs. 121 [8.1 percent] of 1,506 patients in the placebo group.