Transjugular Intrahepatic
Portosystemic Shunts (TIPS)
What is portal hypertension?
In people with liver failure and cirrhosis,
the liver is incapable of processing blood from
the bowels. As a result, abnormally high pressure
develops within the veins that drain blood from
the bowels as the body tries to form other channels
for the blood to empty into the main (systemic)
circulation. These alternate pathways of blood
drainage are known as portosystemic collaterals
and consist of fragile veins that surround the
esophagus, stomach or other areas in the digestive
tract.
Because of the fragility of these veins, they
are prone to rupturing, which can result in massive
amounts of bleeding. The abnormally high pressure
within the veins draining into the liver (portal
hypertension) can also result in the formation
of fluid seeping from the surface of the liver
and collecting in large quantities in the abdominal
cavity. This is known as ascites. Therapies that
lower the blood pressure within the veins draining
into the liver can lessen the formation of ascites
and lower the risk of bleeding from the fragile
veins (varices).
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What
treatments can lower the blood pressure in the
portal venous system?
A number of therapies can lower the pressure
of the veins that drain from the bowel into the
liver. The first choice of therapy usually consists
of drug therapy with medications known as non-selective
beta-blockers. These medications need to be taken
everyday to produce an effect. Some people may
not be able to remain on beta-blocker therapy
if they develop side effects from taking them.
Other people on beta-blocker therapy will remain
at risk for bleeding from varices and from the
development of fluid formation (ascites).
Another approach is to seal off the veins to
prevent rupturing. In sclerotherapy, a camera
(endoscope) is passed down through the esophagus
to inject the abnormal veins with substances that
close them off. With variceal band ligation, the
abnormal veins are tied off with small rubber
bands. Although sclerotherapy and variceal band
ligation are very effective in targeting the abnormal
and fragile veins around the esophagus, they do
not lower the pressure of the blood inside the
portal venous system. This portal hypertension
may continue to allow fluid to develop inside
the abdominal cavity, or may allow bleeding to
occur from other areas of the bowel such as the
stomach (portal gastropathy).
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Transjugular
Intrahepatic Portosystemic Shunts (TIPS) and Surgical
Shunts
Pressure inside the portal venous system draining
blood into the liver can be relieved by shunting
blood away from these veins. Surgical portacaval
shunts require an abdominal incision followed
by sewing together a portion of the portal venous
system to the main venous system. Often these
two structures are connected using a short piece
of tubing made of Teflon /trademark/. The surgical
shunts are highly effective at reducing the risk
of bleeding from varices. Most surgical shunts
will also relieve ascites. The main drawback of
surgical shunts is that they are major vascular
surgery, and may be associated with a high risk
of complications in some patients.
The transjugular intrahepatic portosystemic shunt
(TIPS) acts like a surgical shunt in diverting
blood away from the congested portal vein into
the main venous system, but it is minimally invasive
(not major) surgery. Unlike surgical shunts, TIPS
is performed through a small nick in the skin,
working through specialized instruments, which
are passed through the body using an x-ray camera
for guidance. The TIPS procedure creates a shunt
within the liver itself, by linking the portal
vein with a vein draining away from the liver
(a hepatic vein) together with a device called
a stent. The stent acts a scaffold to support
the connection between these two veins inside
the liver. With the TIPS stent in place, the pressure
inside the portal veins is relieved by the blood
draining through the stent into the vein draining
blood away from the liver.
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Liver
Transplant
The best way to relieve the excessive pressure
within a person’s portal venous system is
by replacing their liver with a new one capable
of filtering the blood. However, many people are
not candidates for a liver transplant. The selection
process for determining who is a good candidate
for a liver transplant may be complicated and
require a long period of time. Even in people
who are candidates for a liver transplant, less
than a third will ever receive a liver; in these
people, TIPS may serve as a potentially lifesaving
bridge to transplantation while they await the
availability of a donor liver.
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How
well does a TIPS work?
Over 90% of people that undergo TIPS to prevent
bleeding from varices will have a relief in their
symptoms and experience little to no bleeding
thereafter. When TIPS is performed for ascites,
60-80% of people will have relief in their ascites.
Some of these patients will no longer require
paracentesis, a procedure where a needle is placed
into the abdominal cavity to drain away excessive
fluid. Other patients will still need paracentesis,
but much less often than before the TIPS procedure.
When TIPS is performed for other liver conditions,
such as Budd-Chiari syndrome, many patients will
have a return to nearly normal liver function
once the congested blood drains through the TIPS.
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How
long will a TIPS work?
Unfortunately, the TIPS can develop areas
of narrowing or blockage within the liver. Usually,
these areas can be detected early through regular
ultrasound scans performed every three months.
Once an area of narrowing has been identified,
it can be treated with a balloon to widen the
area of blockage (angioplasty). The angioplasty
restores normal blood flow through the TIPS. This
procedure, known as a TIPS revision, can be performed
as a day procedure on an outpatient basis.
Ongoing research to improve TIPS technology includes
a TIPS created with special metal sleeves (stents)
lined with a thin synthetic covering to act as
an inert barrier between the stent and the liver.
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How
will I know if I am a candidate for TIPS?
Most patients with portal hypertension do
not need to have a TIPS. Patients that have esophageal
varices and problems with bleeding can often be
managed with the drug therapy described above.
However, for those patients that continue to be
at risk for bleeding or who cannot tolerate the
usual first-line treatments, TIPS may be an effective
form of therapy. In patients with ascites who
continue to form large amounts of fluids within
their abdomen, even while taking water pills (diuretics),
and who require frequent sessions of paracentesis
to drain away the fluid, TIPS may also be a very
effective therapy.
TIPS is performed by an Interventional Radiologist.
The Interventional Radiologist will determine
from your medical history, physical, blood work
and liver imaging (CT scans, ultrasounds and/or
MRI scans), in consultation with your gastroenterologist,
hepatologist, or surgeon, whether or not you are
a candidate for TIPS.
You should discuss all your treatment options
with your physician. Some questions to ask include:
- Can my portal hypertension be controlled with
drug therapy?
- What medications might be appropriate for
me?
- If a procedure is required, am I a candidate
for a less invasive, Interventional Radiology
treatment like a transjugular intrahepatic portosystemic
shunt?
- What are the risks and benefits of the treatment
plan prescribed for me?
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What
are the risks of TIPS?
Because blood that normally flows through
the liver gets bypassed through a TIPS, some of
the substances absorbed into the body from the
intestines can build-up within the blood stream
and produce a condition known as hepatic encephalopathy.
This is a condition that can affect your brain,
causing difficulty in concentration, excessive
sleepiness and, in rare cases, a coma.
Most cases of hepatic encephalopathy are manageable
by taking a medication known as lactulose. This
is a laxative in a syrup form that reduces the
amount of certain types of toxins absorbed by
the intestines into the blood stream. In rare
situations, a person can develop severe hepatic
encephalopathy after TIPS. If this occurs, the
TIPS may need to be closed off or a smaller stent
placed within the original stent to slow down
the amount of blood passing through the TIPS.
Other risks of TIPS include hepatic failure, bleeding
and infection.
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Reviewed by: Timothy
W.I. Clark, MD
April 2003
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