Kidney Disease Research Updates
Spring/Summer 2009

Aspirin and Anti-clotting Drug Combination Reduces Risk of Dialysis Access Failure

A combination of aspirin and the anti-platelet drug dipyridamole has been shown to significantly reduce blockages and extend the useful life of new artery-vein access grafts used for hemodialysis, according to a study by the Dialysis Access Consortium (DAC). The study, supported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), was published in the May 21, 2009, issue of the New England Journal of Medicine.

Artery-vein access grafts, called arteriovenous (AV) grafts, fail most often due to narrowing of blood vessels at the graft site and subsequent clotting, which blocks the flow of blood. A blocked graft cannot be used for dialysis and is a common complication for dialysis patients.

Reduced Failure

The DAC trial found that the combination treatment decreased the rate of loss of primary unassisted graft patency—the useful life of a graft before it becomes blocked the first time—by 18 percent and the rate of developing significant stenosis by 28 percent, compared with placebo. Previous smaller clinical trials of anti-clotting therapies failed to show that these drugs improve AV graft patency or that they could be used safely in dialysis patients.

“This drug combination provides a modest but important new therapy to keep AV grafts in good working order so patients can get the dialysis they need,” said NIDDK Director Griffin P. Rodgers, M.D., M.A.C.P, “but clearly more research is needed to extend the useful life of AV grafts.”

A total of 649 participants with new AV grafts were recruited for the trial at 13 clinical sites in the United States and were randomly assigned to treatment with dipyridamole plus aspirin or to a placebo. The trial took place over a period of 5 years.

“Our trial results show that we now have a drug therapy that significantly prolongs the viability of AV grafts,” said Bradley S. Dixon, M.D., an associate professor of nephrology at the University of Iowa College of Medicine, Iowa City, and lead author of the study. “This is an important step forward as we proceed to develop therapies to improve dialysis patients’ quality of life.”

Collaboration

The NIDDK established the multicenter DAC in September 2000 to design and implement a series of randomized, controlled, clinical trials to identify effective therapies that reduce the rate of graft and fistula failure in dialysis patients.

Participating DAC institutions include

• Boston University, Boston
• University of Iowa, Iowa City
• Duke University, Durham, NC
• Maine Medical Center, Portland
• University of Alabama, Birmingham
• University of Texas Southwestern Medical School, Dallas
• Washington University, St. Louis
• Cleveland Clinic Foundation, Cleveland

According to the 2008 U.S. Renal Data System Annual Data Report, more than half a million patients have kidney failure, 70 percent of whom are on dialysis. Annual costs for kidney failure are more than $30 billion, and annual costs of vascular access-related procedures in the United States have been estimated to exceed $1 billion.

The National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) has information about kidney diseases. For easy-to-read booklets and fact sheets, including a fact sheet about vascular access, visit the NKUDIC website at www.kidney.niddk.nih.gov.

NIH Publication No. 09–4531
August 2009

[Top] [Next Article]