Module 7 Liver Vasculature Flashcards
1
Q
The evaluation of the portal system is a common procedure often related to what?
A
Chronic liver disease and cirrhosis of the liver
2
Q
Liver vasculature evaluation includes the evaluation of what? 5
A
- Hepatic veins
- Portal veins
- Hepatic Artery
- IVC
- Collaterals
3
Q
Some of the vascular disorders we will look at are what? 3
A
- Portal hypertension
- Shunts/Stents
- Transplants
4
Q
What are two types of portal hypertension?
A
- Portal vein thrombosis
- Hepatic vein thrombosis
5
Q
How many major hepatic veins are there?
A
Three
6
Q
Where do the MHV and the LHV typically join?
A
Before the IVC
7
Q
Which Hepatic vein is typically duplicated?
A
Left hepatic veins
8
Q
What do the hepatic veins drain into?
A
The IVC and become larger in diameter on their approach
9
Q
What does Hepatic Vein waveforms look like typically?
A
Respirophasic and pulsatile
10
Q
Why do we evaluate the hepatic veins?
A
We assess for patency or distension
11
Q
What does this image demonstrate?
A
The hepatic veins draining into the IVC
12
Q
What does the portal veins drain?
A
Blood from the bowel and spleen to the liver
13
Q
How much blood does the portal veins supply to the liver?
A
Approximately 75%
14
Q
The MPV is comprised of what?
A
Splenic and superior mesenteric veins
15
Q
The MPV enters the liver through what?
A
The porta hepatis
16
Q
When describing flow in the portals and hepatic veins we use what terms?
A
- Hepatopetal
- Hepatofugal
17
Q
What does hepatopetal mean?
A
Towards the liver
18
Q
What does hepatofugal mean?
A
Away from the liver
19
Q
Portal veins have a low velocity normally, what is the range?
A
16-40 cm/s (variable- depends on source)
20
Q
What is the flow relatively for portal veins post prandial?
A
Flow increase post prandial
21
Q
The normal MPV diameter should be what?
A
Less than 13 mm
22
Q
What does this image demonstrate?
A
MPV
23
Q
What does this image demonstrate?
A
LPV
24
Q
What does this image demonstrate?
A
RPV
25
How much blood does the hepatic artery supply to the liver?
25%
26
What kind of path does the Hepatic artery have?
tortous
27
Where is the proximal hepatic artery seen?
At the celiac axis
28
Where is the distal hepatic artery seen? 2
1. Intercoastal
2. MPV and RPV
29
Where is the distal hepatic artery seen?
1. Intercoastal
2. MPV and RPV
30
What is the resistance like in the hepatic artery?
Low resistance
31
Is there normally spectral broadening in the hepatic artery?
Yes, because the vessel is quite small
32
What is the velocities of the Hepatic artery?
Variable so RI is used to assess for pathology
33
What is the normal Resistive index?
0.5 - 0.7
34
What is the IVC formed from?
Iliac veins
35
Where is the IVC located?
Anterior to the spine and right of the aorta
36
What is the size of the IVC?
Variable, greater then 2.5 cm considered dilated
37
What does the IVC spectral trace look like? 3
1. Spontaneous waveform?
2. pulsatile proximal
3. Phasic distally
38
What is the IVC spectral trace influenced by?
Heart and respiration
39
What categories can portal hypertension be categorized into? 3
1. Pre- hepatic
2. Intrahepatic (most common)
3. Post hepatic
40
What is the leading cause of portal hypertension?
Cirrhosis
41
What is the leading cause of cirrhosis?
Hepatitis C followed by alcoholism
42
What are the signs and symptoms of portal hypertension? 5
1. Jaundice
2. Abnormal LFT
3. Ascites (increased abdominal girth)
4. Splenomegaly
5. GI bleed
43
What are two types of GI bleeds?
1. Hematemesis (vomiting blood)
2. Melena (dark starry stools)
44
For a portal hypertension physical examination the patient can present with what? 2
1. Caput medusae (dilated abdominal wall veins)
2. Hepatic encephalopathy (confusion due to poor liver function)
45
What is Pre-hepatic obstructions?
1. Pathology that occurs to blood flow before it enters the liver (inflow)
46
What are some examples of pre-hepatic obstruction? 4
1. Portal or splenic vein thrombosis
2. Portal or splenic vein invasion
3. Extrinsic compression by tumor
4. Inflammation of the pancreas (pancreatitis)
47
Portal vein thrombosis can be caused by what? 5
1. Cirrhosis (20%)
2. Malignancies (20%)
3. Hypercoagulable states
4. Intra- abdominal inflammation/ infection
5. Trauma (From surgery)
48
Chronic PHT may be asymptomatic or symptomatic?
Asymptomatic
49
What does Portal vein thrombosis look like sonographically?
Can appear enlarged (>15mm)
50
How may the lumen echogenicity appear during portal vein thrombosis? 4
1. Hyperechoic
2. Hypoechoic
3. Isoechoic
4. Anechoic
51
What might the portal vein thrombosis appear in spectral?
There may be an absence of flow with spectral, color, or power doppler
52
What might portal vein thrombosis look like? 2
1. Cavernous transformation
2. HA enlarged/ increased flow
53
Portal vein thrombosis tends to last how long?
It tends to be permanent leading to scarring
54
What happens to the vessels during Portal vein thrombosis?
The vessel virtually disappears
55
What are three pitfalls to be aware of for portal vein thrombosis?
1. Undetected anechoic tumor/ thrombus
2. Low velocity flow undetected
3. Inadequate doppler angle
56
What is the most common cause of portal hypertension?
Intrahepatic obstruction
57
What are intrahepatic obstruction underlying diseases? 4
1. Cirrhosis
2. Hepatitis
3. Hepatic fibrosis
4. Nonalcoholic steatohepatitis (NASH)
58
What is intrahepatic obstruction? And what does it lead to?
Inflammation of normal liver tissue which leads to death and fibrosis
59
What does Intrahepatic obstructions lead to? 4
1. Damage to liver, sinusoids and hepatocytes
2. Increased resistance to blood flow at the sinusoid level
3. Shunting of blood to collateral vessels
4. Varicies develop
60
Near the end stage of intrahepatic obstruction what happens to the liver and spleen?
The liver will decrease in size and the spleen will increase in size
61
What is this an example of?
Liver cirrhosis
62
What is poste hepatic obstruction?
When drainage of blood from liver (outflow) is compromised
63
What is post-hepatic obstruction caused by? 3
1. Chronic right sided heart failure
2. Tricuspid regurgitation
3. Budd chiari (thrombosis of the HV and IVC)
64
If Post hepatic obstruction is acute, what does the liver do?
The liver enlarges and so does the spleen
65
For post hepatic obstruction if there is increased right side heart pressure what can be the cause?
CHF or TR
66
What is the the spectral of PV look like?
Pulsatile
67
What is Budd chiari?
A rate condition that is most commonly caused by a hyper coagulable state like polycythemia
68
What drugs can also lead to thrombosis somtimes?
Oral contraception
69
What collaterals sometimes form during budd chiari?
They may form a caudate lobe which may help drain the liver
70
What does this image demonstrate?
IVC obstruction
71
What does the image demonstrate?
Hepatic vein obstruction
72
What is the patency of MPV and branches? What are some questions we should ask? 3
1. Presence or absences of thrombus
2. Is there lack of flow?
3. Are there collaterals?
73
What are some questions we should ask when doing duplex documentation? 4
1. What is the patency of MPV and branches
2. What is the direction of flow
3. What is the phasicity
4. What is the MPV velocity
74
What is MPV velocity?
16-40 cm/sec
75
What are waveform changes? 2
When the waveform becomes either
1. Bi-phasic
2. Flow reversal
76
What does waveform changes mean? 2 (biphasic/ flow reversal)
1. If its bi-phasic - alternative antegrade/ retrograde flow
2. If its flow reversal- severe PHT
77
Why do collaterals flow?
In the event of portal hypertension is a key finding
78
How many way can we take to return to the heart?
There are several natural collateral pathways
79
What are alternative ways to bypass the liver and decompress the system?
Surgical intervention such as therapeutics shunts are used in severe cases to prevent GI bleeds and improve quality of life
80
What are portosystemic collateral and shunts? What do they normally drain into?
1. Pre- existing vessels
2. Normally drain into portal, splenic, and mesenteric vessels
81
What are the three major congenital shunts?
1. Portocaval
2. Mesocaval
3. Splenorenal
82
What does the portocaval drain?
PV to IVC
83
What does the mesocaval drain?
SMV to IVC
84
What does the splenorenal drain?
SV to Lt. RV
85
Why would we use portosystemic collaterals and shunts?
SO vessels develop or recanalize with portal hypertension to allow blood to circulate back to the IVC
86
What does the portosystemic collaterals and shunts look after a while?
Seen as dilated vessels and appear as "too many tubes" or a "can of worms"
87
A backup of blood flow ends up where in the portosystemic collaterals and shunts?
A backup of blood flow ends up in the organs they are draining and cause enlargement (splenomegaly)
88
what is the most prevalent portosystemic collateral?
The coronary vein (left gastric)
89
Increased pressure in the coronary vein may cause what?
Esophageal varices
90
Why does increased pressure causes the coronary vein to cause esophageal varices?
These vessels are not made for the volume of blood they now receive
91
Visualization implies an increase risk for what?
Hemorrhage which is life-threatening
92
With PHT the remnant of the umbilical vein does what? What is the flow? 3
1. Recanalizes in the ligamentum teres
2. From the LPV to the umbilicus
3. Flow is hepatofugal
93
What kind of devices can decompress the portal system? How can it be inserted?
A surgical shunt, it can be placed surgically or with an endovascular technique
94
The most common shunt for PHT is what?
TIPS
95
What does TIPS stand for?
Trans-jugular intrahepatic portosystemic shunt
96
What is TIPS?
A metallic, expandable stent is placed in the liver tissue shunting blood from PV to HV
97
What is the endovascular technique for placing TIPS?
Catheter passed down IJV into HV, Advancing through liver tissue into PV branch
98
What is the success rate for TIPS?
100%
99
What should we do to follow up for TIPS?
Assess with TIPS
100
What does this image demonstrate?
TIPS
101
Ultrasound is used to confirm what in terms of TIPS?
Patency and search for stenosis
102
In a normal TIPS the velocity range is what?
90-190 cm/s
103
Normal PV velocity is at least what?
30 cm/s
104
What is the flow in TIPS? 2
1. Flow is retrograde in the right and left portal
2. Compensatory increased flow seen in HA
105
What is early complication of TIPS? What can this increase/ decrease?
1. Usually due to thrombosis
2. Will increase velocities in the stenosis (>190cms)
3. Can decrease velocities in the MPV (<30 cms)
106
What is late complications of TIPS?
Neo- intimal hyperplasia invades stent
107
What is neo-intimal hyperplasia?
An over reaction of the bodies normal healing process
108
If a stenosis is detected in TIPS what do we do?
Balloon angioplasty and thrombolysis can be done
109
What is a liver transplant used for?
Treatment for end stage liver disease
110
How much of a liver can be used for a liver transplant?
Whole or partial (typically right)
111
what is used for pre and post operative assessment liver transplant patients?
Duplex ultrasound
112
During post operative assessment what doe we look at to confirm patency, flow direction and size? 4
1. HA
2. PV
3. IVC and HV
4. Splenic and mesenteric veins
113
What may be larger in the liver transplant patient? And what is the normal size?
The portal vein can be larger in the transplant patient with normal size up to 15 mm
114
What are complications to transplant livers? 6
1. Rejection
2. Pseudo aneurysm
3. Hepatic infarction
4. Thrombosis of major liver vessels
5. Stenosis may be observed at the surgical anastomosis sites in follow up exams
6. Other concerns can be hematomas, abscess formation and AV fistulas
115
What are some thrombosis's that might be complications in liver transplants? 3
1. HA thrombosis early post-op complications
2. Stenosis of anastomosis sites
3. PV thrombosis, air
116
When is a ultrasound usually done after a liver transplant?
Typically done within 24 hours of the surgery and at regular intervals afterwards
117
The HA should have what type of appearance in the post liver transplant?
Should have a rapid upstroke and an RI
118
What should the RI be for a post transplant liver?
0.55 - 0.8
119
What can we note about PSVs in the transplant liver?
PSV is variable and is not reliable
120
HV's can have what type of waveform post transplant?
Monophasic waveform immediately after the surgery but will normalize over time
