Implant Device Designed to Prevent Blood Clots in Vascular Grafts

Surgeons at the Methodist DeBakey Heart Center in Houston were among the first in the U.S. to implant a new vascular graft engineered to reduce the risk of blood clots in patients treated for peripheral arterial disease (PAD), which affects as many as 12 million Americans over the age of 50.

The new Gore graft, approved for use in the U.S. in November, is the first vascular graft available in the U.S. that has a blood-thinner permanently bonded to its surface to prevent clotting long-term. It is part of an emerging class of products that combine mechanical and biological elements to address severe atherosclerosis.

?Because the blood-thinning drug stays on the graft, rather than flowing out into the blood stream, this graft prevents blood clots from forming inside the graft and causing graft failure,? said Dr. Alan B. Lumsden, M.D., vascular surgeon at the Methodist DeBakey Heart Center, who performed the surgery on a 66 year old man Wednesday. ?The procedure involves bypassing the clogged artery to create a new route blood can take to feed the patients? legs.?

PAD is a buildup of plaque in the wall of an artery that results in narrowing or blocking of the artery, limiting blood flow to the legs and causing anything from severe leg pain to gangrene and amputation. Severe cases are commonly treated with surgical bypass of the clogged vein, using either a synthetic graft or another healthy vein from the patient.

?Most vascular surgeons have been frustrated by the inability of synthetic grafts to perform as well as vein grafts in lower-limb bypass,? Lumsden said. ?Close to a third of patients simply don?t have the option of using one of their own veins. These new grafts are showing results that are remarkably close to the success of using a patient?s own vein for treatment.?

“Bonding an anti-coagulant to the graft is a quantum leap ahead in vascular surgery,? Lumsden said. “It?s exciting and personally gratifying to see this come to fruition in one of my own patients, validating years of medical research.?
Lumsden was involved in early imaging studies of heparin-bonded graft, which showed a major improvement in the clinical performance of grafts bonded with heparin over those that are bare. Trial data has since confirmed that heparin-bonded grafts perform competitively with the success of bare grafts.

Key findings from clinical trial supporting Gore Propaten vascular graft
? Over 10,000 Gore Propaten vascular grafts have been successfully implanted worldwide in four years of commercial availability in the European U_nion and other overseas countries.
? The average one-year primary patency for the Gore Propaten vascular grafts in below-knee bypasses has been reported to be 80 percent.1 This compares favorably to the average one-year patencies for autologous vein grafts (81 percent) and ePTFE synthetic grafts (66 percent) in the same application.2

1 Walluscheck KP. Heparin-bonded expanded polytetrafluoroethylene vascular graft for occlusive vascular disease of the lower extremity. Italian Journal of Vascular & Endovascular Surgery 2006;13(3):137-147.
2 Data based on an analysis of current literature: several Medline searches were performed to identify publications pertaining to ePTFE synthetic vascular graft and vein infragenicular bypasses. Search criteria included (1) articles published from January 2000 to September 2005, (2) key words used were below knee, polytetrafluoroethylene, prosthetic, bypass, patency, (3) articles in English language, (4) N equal or greater than 30 bypasses, (5) clinical publications, (6) reviews, case reports or meta-analysis articles were excluded, (6) articles containing the key word AV access (including synonyms) were excluded. Articles that did not meet the above criteria were deemed ineligible for this analysis. Data of analysis on file.

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