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Hemodialysis requires frequent access to the patient's blood stream
(vascular system). Vascular access has been called the "Achilles'
Heel" of hemodialysis care. Hemodialysis vascular access procedures
and associated costs come to $8,000-10,000 per patient per year.
This amount represents approximately 25 percent of total ESRD medical
costs. The most common problems are stenosis (narrowing of graft/blood
vessel), infection, and thrombosis (clotting).
At present, three types of vascular access are predominant: AV
(arteriovenous) fistulas, AV grafts, and catheters. AV fistulas
are surgically created by connecting a patient's own artery and
vein, usually in the forearm. AV fistulas have the lowest rate of
complications, but take from several weeks to several months to
mature, heal, and develop in size. Over time, an AV fistula becomes
large enough to accommodate the needles required for hemodialysis.
AV grafts are also created surgically, but use a synthetic blood
vessel to connect the vein and artery. The needles are inserted
into this synthetic graft. AV grafts require shorter times (if any)
to heal before they can be used, but tend to have more incidents
of stenosis and thrombosis than AV fistulas. Catheters are most
often used as "bridge" devices, used to bridge the time
between from start of dialysis treatments (often an emergency) to
when the patient's AV fistula or AV graft has matured and is ready
for use. Catheters are generally not used as long-term devices as
they tend to have higher rates of infection and thrombosis.
In an effort to reduce vascular access problems, several companies
are developing new implantable devices that have self-sealing ports
that permit the needles to be inserted in the same place every treatment.
This may prove to reduce the complications seen with fistulas, grafts,
and catheters and may also make it easier for hemodialysis patients
to perform their own dialysis treatments at home.
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