A new study shows patients who have low blood pressure or experience a sudden drop in blood pressure while undergoing dialysis are at an increased risk of blood clotting at the point where the blood vessels are connected to the dialysis machine, which is known as vascular access.
"Vascular access is their lifeline. It's required for dialysis, and without dialysis, they'll die," Tara Chang, M.D., a Stanford nephrologist and lead author of the study, was quoted as saying.
In dialysis, blood is cleaned by exchanging fluid and electrolytes across a membrane during a three- to four-hour session. One of the most common forms of vascular access is a fistula, which is created surgically from the patient's own blood vessels. The tubes to take blood to and from the body to the dialysis machine are connected to the body at this access point. Clotting is a major complication of an access point. It can lead to its closure.
"These access points don't last forever," Chang said. "Many patients go through multiple access points moving from the right to left arm, or into the legs if necessary after repeated failures in the arms. 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 investigators found patients who had the most frequent low blood pressure episodes during dialysis were two-times more likely to have a clotted fistula than those with the fewest episodes. According to the researchers, low blood pressure during dialysis occurs in about 25 percent of dialysis sessions.
Previous research has shown a dip in blood pressure during dialysis can lead to strokes, seizures, heart damage, and even death. Patients experiencing this problem are also at risk for short-term troubles like gastrointestinal, muscular and neurologic symptoms.