Low blood pressure ups dialysis clot risk

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STANFORD, Calif., July 30 (UPI) -- Kidney patients undergoing dialysis have an increased risk of blood clots when blood pressure drops, U.S. researchers say.

Lead author Dr. Tara Chang, a Stanford University nephrologist, and colleagues at the University of Utah say most patients with kidney failure sit in a chair three or more times a week connected to an artificial kidney machine.

Blood is cleansed through an exchange of fluid and electrolytes across a membrane during each 3- to 4-hour session. Patients are attached to the dialysis machine several ways.

"Our analysis shows another adverse consequence associated with a fall in blood pressure during dialysis for patients," Chang says in a statement. "Vascular access is their lifeline. It's required for dialysis and without dialysis, they'll die."

This point of vascular access is known as the "Achilles' heel" of patients on dialysis, Chang says.

One common forms of vascular access is a fistula -- created surgically from the patient's own blood vessels. The tubes used to take blood to and from the body to the dialysis machine are connected to the body at this access point. Clotting is one of the main complications of an access point and can lead to its closure, Chang says.

"These access points don't last forever," Chang says. "Many patients go through multiple access points in the arms and legs. When a patient runs out of access points, it becomes an emergency situation. Anything you can do to extend the life of the access point is important."

The findings are published in the Journal of the American Society of Nephrology.