Chapter 27: The Hepatoportal System Flashcards
an abnormal connection between the hepatic artery and the portal venous system
arterioportal fistula
an abnormal connection between the hepatic artery and the hepatic vein
arteriosystemic fistula
an abnormal accumulation of fluid within the peritoneal cavity. It is the most common complication of cirrhosis
ascites
any nonmalignant venous thrombosis. This term is most often used in the context of malignancy, to differentiate malignant from nonmalignant thrombus
bland thrombus
hepatic venous outflow obstruction at any level from the small hepatic veins to the junction of the IVC and the right atrium, regardless of the cause of obstruction
Budd-Chiari syndrome
A chronic diffuse degenerative disease in which normal liver cells are damaged and replaced by fibrous connective tissue and regenerating nodules
cirrhosis
spiraling, swirling, “helix” flow pattern demonstrating hepatopetal, hepatofugal, or simultaneous bidirectional flow; uncommon flow pattern seen in 2% of the population
Helical portal vein flow
Compensatory mechanism to maintain perfusion to the liver by arterial vasodilation when portal vein flow is obstructed in patients with advanced cirrhosis
hepatic arterial buffer response
a pleural effusion in patients with liver cirrhosis in the absence of cardiopulmonary disease. The pathophysiology involves the passage of ascitic fluid from the peritoneal cavity to the pleural space through diaphragmatic defects
hepatic hydrothorax
Refers to retrograde flow, away from the liver (physiologically abnormal direction of flow within portal-splenic venous system)
hepatofugal
Refers to antegrade flow; toward the liver (pathophysiologically normal direction of flow within the portal-splenic venous system)
hepatopetal
Elevated pressure gradient between the portal vein and IVC or hepatic veins of 10 to 12 mm Hg or greater
portal hypertension
formation of abnormal blood vessels that shunt portal blood flow bypassing the liver to the systemic circulation, decompressing increased portal venous pressure
portosystemic collaterals
formerly known as hepatic veno-occlusive disease; is a syndrome of tender hepatomegaly, RUQ pain, jaundice, and ascites; most often occurring in patients in patients undergoing hematopoeitic cell transplantation, and less commonly following radiation therapy to the liver, liver transplantation, and ingestion of alkaloid toxins
sinusoidal obstruction syndrome (SOS)
a percutaneously created connection within the liver between the hepatic vein and the portal vein that allows blood flow to bypass the liver as a means to reduce portal pressure in patients with complications related to portal hypertension
transjugular intrahepatic portosystemic shunt (TIPS)
Indications for hepatoportal duplex ultrasound
liver cirrhosis
portal hypertension
thrombus
Budd-Chiari syndrome
Pre/post interventional procedures
abdominal trauma
sudden onset of ascites
patients with a history of abdominal malignancy
most often joins the portal system at the splenoportal confluence; with portal hypertension, diameter <7mm; can demonstrate hepatofugal flow that often leads to esophageal varices
coronary vein (left gastric vein)
origin, gastroesophageal junction, lower esophagus, and submucosal region of the gastric fundus; dilated vessels posterior to the left lobe of the liver at the GEJ
gastroesophageal veins
fetal remnant arising from LPV, coursing along the anterior edge of the falciform ligament to the abdominal wall; connects to systemic veins around the umbilicus “caput medusa”; located in the fissure for the ligamentum teres; diameter >3mm, hepatofugal flow
recanalized paraumbilical vein/abdominal wall
large tortuous vessels seen in the hilar region of the spleen and left kidney; shunts blood to the left renal vein, terminating in the IVC, decompressing the portal circulation
splenorenal veins
portosystemic shunt between the cystic vein and the right branch of the portal vein, systemic veins of the anterior abdominal wall, or patent portal vein branches within the liver; dilated pericholecystic vascular channels, 3-8 mm in diameter within or outside the gallbladder wall, demonstrating low-velocity continuous flow
gallbladder varices
most common imaging technique used to evaluate the liver and its vasculature
duplex sonography
The hepatic artery supplies approximately ____ of blood to the liver
25%
carries oxygenated blood through branches in portal triad and enters sinusoids to reach central veins within liver
hepatic artery
The portal vein supplies approximately ____ of blood to the liver
75%
carries nutrient rich blood from the gastrointestinal tract to the portal triad and enters sinusoids to reach central veins
portal vein
Dual blood supply liver
hepatic artery
portal vein
actual beginnings of hepatic venous systems; enter sublobular veins, which unite and converge to form 3 hepatic veins that drain into IVC
central veins
The ______ comprise primary hepatic outflow vessels.
hepatic veins
The portal triad consists of:
branch of hepatic artery
branch of portal vein
bile duct
begins at junction of splenic vein and superior mesenteric vein
main portal vein
runs along lesser curvature of stomach; drains into portal system near portal splenic confluence
main portal vein
The main portal vein lies ____ to the IVC>
anterior
transverse fissure on visceral surface of liver between caudate and quadrate lobes
porta hepatis
At the porta hepatis, the _____ and _____ enter the liver and the _____ leaves the liver.
portal vein
hepatic artery
hepatic duct
The main portal vein divides into a smaller, more anterior and cranial _____ portal vein and a larger, more posterior and caudal ____ portal vein.
left
right
The portal veins branch into ____ and ____ divisions on the left.
medial
lateral
The portal veins branch into ____ and _____ divisions on the right.
anterior
posterior
The _____ have no valves.
portal veins
composed mostly of loosely arrayed, non parallel connective tissue fibers and minor amount of collagen
main portal vein
composed mostly of tightly packed collagen fibers
hepatic veins
The hepatic veins are ______.
intersegmental
Patient preparation
fast overnight
The _____ branches off the celiac trunk to the right.
hepatic artery
excellent visualization of porta hepatis
right coronal oblique
provides optimal visualization of splenic vein and splenic artery
left coronal oblique
The liver is evaluated for ____, ___, and ____.
size
texture
surface contour
The normal portal vein diameter during quiet respiration is ___ mm or less.
13
The portal vein may increase up to __ mm with deep inspiration
16
Normal portal venous outfloq
hepatopetal; laminar, low-velocity flow with mild respiratory and moderate pulsatile variations
abnormalities associated with helical flow
portosystemic collaterals
Portal vein velocity ____ during inspiration and _____ during expiration
decreases
increases
Postprandially, portal vein flow velocity increases __-___%
50-100
Resting PSV in portal vein
16 cm/s
mean flow velocity portal vein
19.6 + 2.6 cm/s
Diameter of the splenic vein measures up to __ mm.
10
Normal splenic vein flow and direction
antegrade
Splenic vein velocity _____ during inspiration and _____ during expiration
decreases
increases
Normal PSV of splenic vein
9-30 cm/s
Normal mean velocity of splenic vein
5 to 12 cm/s
Normal spectral Doppler waveform of splenic vein
respirophasic with slight pulsatility
drains into portal system near portal splenic confluence
left gastric or coronary vein
The left gastric vein measures up to __ mm in diameter
6
The superior mesenteric vein can measure up to __ mm at the trunk.
10
Normal flow of SMV
antegrade
Normal PSV of SMV
8 and 40 cm/s
Normal mean velocity of SMV
9 to 18 cm/s
Normal spectral Doppler waveform of SMV
respirophasic with slight pulsatility
SMV velocity ____ during inspiration and ____ during expiration
decreases
increases
Postprandial velocity SMV increases __ - ___ %
50-100
Normal diameter of right hepatic vein
less than 6 mm
The hepatic veins normally exhibit pulsatile waveforms with two ____ waves and two ____ waves.
antegrade
retrograde
Ventricular systole demonstrates the __-wave
S
Ventricular diastole demonstrates the __-wave
D
reflects overfilling of right atrium at end of ventricular systole, resulting in retrograde wave
V-wave
Atrial contraction demonstrates the __-wave
A
The PSV of the hepatic veins ranges between __ and __ cm/s
22
39
The hepatic artery demonstrates ____ flow.
hepatopetal; monophasic, low-resistance waveform with continuous antegrade flow throughout cardiac cycle
When portal venous perfusion decreases, hepatic arterial flow _____
increases
With food ingestion the portal vein velocity _____
increases
The normal PSV of hepatic artery
70-120 cm/s
The mean velocities of the hepatic artery
20-40 cm/s
The normal resistance index of the hepatic artery
0.55 and 0.7
The IVC demonstrates normal ____ flow
antegrade
proximal Doppler IVC
pulsatile due to effects of right atrial pressure
distal Doppler IVC
respirophasic
Normal PSV IVC
44-118 cm/s
IVC size ranges from __ - ____ mm in diameter
1.5-2.5
The IVC is normally dilated ____ level of obstruction
below
hepatopetal flow rerouted away from the liver through collateral channels to low-pressure systemic vessels
portal hypertension
Normal pressure of IVC and hepatic veins
5 and 10 mm Hg
Portal hypertension should be suspected if the pressure gradient exceeds:
10-12 mm Hg
Most common etiology of portal hypertension
sinusoidal obstruction due to cirrhosis
Most common cause of cirrhosis is
hepatitis C
2nd most common cause of cirrhosis is
alcohol abuse
Primary complication of portal hypertension
gastrointestinal bleeding from ruptured esophageal and gastric varices
3 levels of portal hypertension
prehepatic
intrahepatic
posthepatic
An enlarged MPV diameter is an indicator of _____
increased portal venous pressure
Most specific finding of portal hypertension
portosystemic collateral
_____ varices are found in 14-60% of patients
splenorenal
_____ and _____ varices are found in 30-35% of patients.
paraumbilical
abdominal wall
_____ varices are found in 50% of patients.
gastroesophageal
Most prevalent collateral pathway found in 80-90% of patient.
coronary vein or left gastric vein
hepatic arterial flow increases as a homeostatic mechanism to maintain hepatic perfusion
arterialization (increased hepatic artery flow)
hepatic artery enlargement, increased flow, tortuous “corkscrew” appearance, high-velocity flow
arterialization
abnormal communications between the artery and the vein in which blood flows directly from an artery into a vein bypassing some capillaries
arteriovenous fistulae
Three types of intrahepatic fistulas
portosystemic venous
arterioportal
arteriosystemic
Portosystemic venous fistula
portal vein to hepatic vein or IVC
arterioportal fistula
hepatic artery to portal vein
arteriosystemic fistula
hepatic artery to hepatic vein
nonsurgical procedure performed to decompress portal venous system for management of uncontrollable variceal bleedingand refractory ascites
TIPS
curvilinear echogenic structure with corrugated borders that course through hepatic parenchyma and extends squarely into both in flowing portal vein and outflowing right hepatic vein
TIPS stent
Normal velocities in TIPS stent
90 - 190 cm/s
Velocites tend to ____ from portal end to hepatic end of stent
incrase
Mean velocity is ___ cm/s at portal venous end of TIPS stent
95
Mean velocity is ___ cm/s at midportion of TIPS stent
120
Normal spectral waveform in TIPS stent
high velocity turbulent flow and pulsatility; respirophasic
The portal vein velocity may increase ___ to ___ cm/s greater than pre-TIPS velocities
37-47
The hepatic artery may exceed ___ cm/s post TIPS
130
results from flow stasis secondary to cirrhosis and portal hypertension
portal venous thrombosis
sudden onset of ascites, acute abdominal pain, elevated D-dimer
portal venous thrombosis
PVT persists of to 12 months; multiple serpignous vessels can appear within 6 to 20 days after acute occlusion to reestablish portal flow
cavernous transformation
spectrum of hepatic disorders that occur in setting of right-sided heart failure
congestive hepatopathy
increased right atrial pressure creating both antegrade and retrograde componenets
regurgitant portal vein flow
highly pulsatile inverted “W” type pattern; prominent V-wave; diminished S-wave
hepatic vein waveform congestive hepatopathy
results from chronically increased pressure and sinusoidal stasis; causes an accumulation of deoxygenated blood, parenchymal atrophy, necrosis, collagen deposition, fibrosis
congestive hepatopathy
Budd-Chiari syndrome is classified according to:
etiology
site of obstruction
results from endoluminal thrombus or webs
primary hepatic vein obstruction
occurs outside of venous system, maliginant tumor infiltration, parasitic mass, extrinsic compression by neighboring mass
secondary hepatic venous flow obstruction
Collaterals that are most frequently seen that drain into unobstructed hepatic veins
accessory hepatic veins
caudate lobe veins
subcapsular veins
portal veins
condition resulting from toxic injury to hepatic sinusoidal endothelial cells, which then undergo necrosis and sloughing, occluding hepatic sinusoids, and terminal hepatic venules
sinusoidal obstruction syndrome
_______ most commonly occurs after hematopoeitic stem cell transplantation
sinusoidal obstruction syndrome
What percentage of blood is supplied to the liver through the portal vein?
75%
What is the transverse fissure on the visceral surface of the liver between the caudate and quadrate lobes?
porta hepatitis
Which of the following describes the portal veins within the liver?
a. thin, invisible walls; course between the liver segments
b. thin, invisible walls; course within the liver segments
c. thick, bright walls; course between the liver segments
d. thick, bright walls; course within the liver segments
d
Which landmark identifies the start of the proper hepatic artery from the common hepatic artery?
gastroduodenal artery
What is the relationship between the main portal vein and the inferior vena cava?
MPV is anterior to the IVC
Which of the following patient positions offers excellent visualization of the porta hepatis?
a. transverse epigastric
b. transverse right costal
c. right coronal oblique
d. left coronal oblique
c
At which location should the portal vein diameter be measured?
where it crosses the inferior vena cava
Which transducer can be useful for assessing the liver surface for nodularity?
7 to 9 MHz linear
What is normal portal vein diameter with quiet respiration?
13 mm or less
Severe liver disease, presence of portosystemic collaterals, and size mismatch between a donor portal vein and native portal vein can all cause what type of flow in the portal vein?
helical
What does an increase in caliber of less than 20% in the splenic vein during deep inspiration indicate?
portal hypertension
Which of the following increases blood flow within the portal, splenic, and superior mesenteric veins?
a. inspiration and ingestion of food
b. inspiration and exercise
c. expiration and exercise
d. expiration and ingestion of food
d
When assessing hepatic vein flow, the S and D waves should show blood flow toward which organ?
heart
What is a normal resistive index in the hepatic artery?
0.5 to 0.7
What is the most common etiology for portal hypertension in North America?
cirrhosis
What is the primary complication of portal hypertension?
gastrointestinal bleeding
Which of the following is NOT a duplex sonographic finding associated with portal hypertension?
a. increased portal vein diameter
b. decreased or absent respiratory variation in the portal and splenic veins
c. hepatopetal flow in the portal and splenic veins
d. portosystemic collaterals (varices)
c
What is the most common portosystemic collateral shunt in the presence of portal hypertension?
splenorenal varices
What type of flow may be seen in the portal vein when an arterioportal fistula is present?
pulsatile hepatofugal flow
Which of the following is a treatment of portal hypertension that involves jugular vein cannulation with stent placement in the liver?
a. mesocaval shunt
b. splenorenal shunt
c. TIPS
d. PVTS
c
Which of the following is NOT a normal finding in a transjugular portosystemic shunt?
a. hepatofugal flow in the main portal vein
b. velocities within the stent in the range of 90 to 190 cm/s
c. hepatofugal flow in intrahepatic portal veins beyond the site of stent connection
d. increased flow velocities in the splenic vein
a
Upon duplex evaluation of the portal system, the vascular technologist visualizes increased portal vein caliber with no detectable flow by color, power, and spectral Doppler. Increased hepatic arterial flow is also documented. What do these findings suggest?
portal vein thrombosis
Besides IVC dilatation, what distinct finding helps differentiate between congestive heart failure and portal hypertension?
increased pulsatility in the hepatic veins only
Which of the following is NOT a sonographic finding in Budd-Chiari syndrome?
a. dilatation of the IVC with intraluminal echoes
b. pulsatile, phasic flow in nonoccluded portions of the hepatic veins
c. enlarged caudate lobe
d. ascites and hepatomegaly
b
Clinical features of sinusoidal obstruction syndrome include all of the following EXCEPT:
a. sudden onset of hepatomegaly
b. abdominal pain
c. weight loss
d. fluid retention and ascites
c
The junction of the splenic and superior mesenteric veins forms the _____
main portal vein
The ____ portal vein branches into anterior and posterior segments, and the _____ portal vein branches into medial and lateral segments.
right
left
Hepatic veins _____ in size as the approach the diaphragm.
increase
The patient and transducer position that provides optimal visualization of the splenic vein and artery is the ______/
left coronal oblique
Using a lower frequency transducer with a smaller footprint is more effective in obtaining acoustic windows using the ____ approach.
intercostal
In patients with portal hypertension, congestive heart failure, constrictive pericarditis, and portal vein thrombosis, portal vein diameters can be expected to ______
increase
Portal vein flow is normally _____ in direction with constant antegrade flow throughout the cardiac cycle.
hepatopetal
Patients with tricuspid regurgitation, right-sided congestive heart failure, or arteriovenous fistulas may present with ____ flow in the portal vein.
helical
Both the ____ and _____ veins demonstrate monophasic flow with slight pulsatility that is directed toward the liver.
splenic
superior mesenteric
Hepatic veins exhibit ____ waveforms that correspond to cyclic pressure changes within the heart.
pulsatile
With ingestion of food, portal vein flow velocities _____, whereas hepatic artery velocities _____.
increase
diminish
Patient size, right atrial pressure, and fluid overload or heart failure affect IVC _____.
diameter
Portal hypertension becomes significant when the pressure gradient between the portal vein and IVC exceeds _____
10-12 mm Hg
Until recently, the most common cause of cirrhosis was alcohol abuse, however, _____ infection now accounts for a larger percentage of cases.
hepatitis c
Cirrhosis would be considered a(n) ____ cause of portal hypertension.
common
Sonographic findings of portal hypertension can include portal vein diameter greater than __ mm and ______ flow in the portal vein.
16
hepatofugal
The most specific finding of portal hypertension is the detection of ______
portosystemic collateral veins
Color duplex imaging findings of an enlarged hepatic artery with high-velocity, turbulent flow, and a tortuous “corkscrew” appearance is referred to as ______
arterialization
Penetrating trauma, iatrogenic trauma due to liver biopsy, transhepatic cholangiography, and transhepatic catheterization of the bile ducts or portal veins may create a(n) _______ which may cause life-threatening portal hypertension
arterioportal fistulaAn
An abnormal connections between the portal vein and the hepatic vein is termed as _______, which can lead to an increased pulsatility in the portal vein waveform
portosystemic venous fistula
A TIPS is typically placed to the management of uncontrollable _____ and refractory ascites.
variceal
If portal vein thrombosis persists without lysis, development of periportal collateral veins increases and is known as ______
cavernous transformation
A spectrum of hepatic disorders that occurs in the setting of right-sided heart failure and causes an accumulation of deoxygenated blood, parenchymal atrophy, necrosis, collagen deposition, and ultimately fibrosis is termed ______
congestive hepatopathy
Malignant tumor infiltration, parasitic mass, or extrinsic compression from a neighboring mass can result in _____ hepatic venous outflow obstruction./
secondary
A patient with fatigue, abdominal swelling, and signs and symptoms of portal hypertension but with patency of the large hepatic and portal veins would likely be diagnosed with ______
sinusoidal obstruction syndrome
