Ch 20 Hepatoporal System Flashcards
What is ascites?
Abnormal accumulation of fluid within peritoneal cavity
Ascites is the m/c complication of ____?
Cirrhosis
What is budd-chiari syndrome?
-Hepatic venous outflow obstruction at any level from the small HVs to the junction of the IVC + RA
-Due to hypercoagulable states
Differentiate hepatopetal + hepatofugal?
Hepatopetal:
-antegrade flow towards liver
-normal direction of flow within portal-splenic venous system
Hepatofugal:
-retrograde flow away from liver
-abnormal direction of flow
What is helical PV flow?
Spiraling/swirling helix flow pattern demonstrating hepatopetal, hepatofugal, or bidirectional flow (uncommon)
What is helical PV flow associated with?
-Advanced chronic liver disease
-Portal hypertension
-Portosystemic shunts
What is a hepatic arterial buffer response?
Mechanism to maintain perfusion to the liver by arterial vasodilation, when PV flow is obstructed in pt’s with advanced cirrhosis
(when PV perfusion decreases, HA flow increases)
What is hepatic hydrothorax?
-Pleural effusion in pt’s with cirrhosis + absent cardiopulmonary disease
-Ascites from peritoneal cavity travels to pleural space via diaphragmatic defects
What is portal hypertension?
Elevated pressure b/w the PV + IVC or HVs of >10-12mm Hg
What are portosystemic collaterals?
Formation of abnormal blood vessels that shunt PV flow bypassing the liver to the systemic circulation, which decompresses PV pressure
(abnormal communications between the portal system and the systemic circulation)
What is sinusoidal obstruction syndrome (SOS)?
-Aka hepatic veno-occlusive disease
-Syndrome of tender hapatomegaly, RUQ pain, jaundice + ascites
SOS most commonly occurs after ___?
Pt’s undergo hematopoietic cell transplantation
What is transjugular intrahepatic portosystemic shunt (TIPS)?
-Created connection within the liver b/w the HV + PV, allowing blood to bypass the liver + reduce portal pressure in pt’s with portal hypertension
-Manages variceal bleeding + ascites
The liver receives a dual blood supply from what vessels (hepatic blood inflow)?
HA (25%) + PV (75%)
Explain the hepatic blood outflow?
-PV enters the sinusoids to reach the central veins (start of HV drainage)
-Central veins enter interlobular veins (forms 3 HVs)
-HVs drain into IVC
The MPV begins at the junction of ___?
SV + SMV
___ drains into the SV prior to the portal/splenic confluence?
IMV
___ drains into the portal system near the portal/splenic confluence?
Left gastric vein (aka coronary vein)
What is the porta hepatis?
-TRV fissure on posterior surface of liver b/w caudate + quadrate lobes
-Where MPV + HA enters liver + hepatic duct exits liver
Differentiate the characteristics b/w LPV + RPV?
LPV:
-Smaller, anterior, cranial
-Splits into med/lat branches
RPV:
-Larger, posterior, caudal
-Splits into ant/post branches
List 3 characteristics of PVs?
-Intrasegmental (within liver segments)
-No valves
-Walls contain a minor amount of collagen
-Hyperechoic walls
___ is the primary outflow route of blood from the liver?
HVs
Which HV is the largest?
RHV
___ joins to form a common trunk before entering the IVC?
MHV + LHV
List 4 characteristics of HVs?
-Intersegmental (b/w lobes)
-No valves
-Walls composed of mostly collagen
-Only hyperechoic when perpendicular to it
___ drains caudate lobe directly into IVC?
Caudate vein
___ branches off the celiac trunk towards the pt’s right?
CHA
When does the CHA become the PHA?
After the gastroduodenal artery branches off
At the porta hepatis, the PHA splits into ___?
RT + LT branches
Where is the HA in the mickey mouse sign?
RT ear
(lies anteromedial to PV)
HAs run with ___ veins?
Portal
What is the hepatoporal protocol?
2D images of spleen, liver, pancreas, GB + associated vasculature
Spectral doppler:
-HVs + IVC
-Intrahepatic PVs (MPV, RPV, LPV)
-Extrahepatic PVs (SV + SMV)
-PHA
Measure:
-MPV diameter (inner to inner)
Which vessels should we use angle correct with?
MPV + PHA
What is the normal MPV diameter with quiet respiration?
< 13mm
What can the MPV diameter increase to with deep inspiration?
16mm
Normal portal venous flow is ___?
Hepatopetal
What would helical flow look like on CD?
Alternating red + blue bands
PV velocity will increase + decrease during what?
Increase: during expiration + ingestion of food
Decrease: during inspiration + exercise
Normal SV diameter is ___ with quiet respiration?
< 10mm
SV > 10mm indicates ___?
Portal hypertension
Normal SV flow direction is ___?
Antegrade
(going towards portal-splenic confluence)
The SV will decrease in velocity during ___ + increase during ___?
Inspiration, expiration
Normal SMV diameter with quiet respiration is ___?
< 10mm
Normal SMV flow is ___?
Antegrade
What is the normal RHV diameter?
< 6mm
What is the normal RHV diameter in pt’s with CHF?
< 9mm
Normal HV flow is ___?
Pulsatile
Explain the HV waveform?
S: systole, below baseline
D: diastole, below baseline
V: end systole, above baseline
A: atrial contraction, above baseline
The HA is larger or smaller in diameter than the PV?
Smaller
Normal HA flow is ___?
Hepatopetal
What would cause the HA flow to decrease?
Ingesting food, this increases pulsatility
Normal IVC diameter?
15-25mm
SF of an obstructed IVC?
Dilated + loss of phasicity
Normal IVC flow is ___?
Antegrade (to RA), pulsatile + have respiratory phasicity
What is the normal pressure in the hepatoportal system?
5-10 mm Hg
What is the m/c cause of portal hypertension?
Sinusoidal obstruction due to cirrhosis
SFs of the 3 stages of cirrhosis?
Stage 1: liver enlarged + echogenic
Stage 2: coarse + heterogeneous
Stage 3: nodular, RLL atrophied + enlarged caudate
How does cirrhosis affect the PV + HV flow?
PV: increases resistance
HV: obstructs
3 SFs of portal hypertension?
-Loss of phasicity
-Bidirectional flow
-Hepatofugal flow (severe)
What is the most specific finding of portal hypertension?
Portosystemic collateral veins (varices)
What is the most prevalent collateral vein associated with portal hypertension?
Left gastric vein (>7mm is dilated)
What causes gastroesophageal varices?
Reverse flow in the left gastric/coronary vein
Where do splenorenal varices shunt blood to?
To the LRV, then the IVC (decompresses portal circulation)
What is recanalization of the PUV?
-Fetal remnant arising from the LPV coursing along anterior edge of falciform ligament to the abdominal wall
-Connects to systemic veins around umbilicus “caput medusa” sign
Where is recanalization of the PUV located?
In fissure for the ligamentum teres
What is arterialization?
PV obstruction (due to cirrhosis or PVT) which increases resistance + decreases PV flow
What happens to the HA when arterialization occurs?
-Enlarged with high velocity flow
-Tortuous corkscrew appearance on CD
What is an AVF?
Abnormal connection b/w artery + vein
1) arterioportal (HA to PV)
2) portosystemic venous (PV to HV/IVC)
3) arteriosystemic (HA to HV)
PVT can be caused by what 2 things?
-Flow stasis secondary to cirrhosis + portal hypertension
-Extrinsic compression from malignancy
What is cavernous transformation?
-The formation of periportal collateral veins within or around a previous PVT
-Occurs if PVT goes untreated for up to 12 months
What is cardiac cirrhosis (congestive hepatopathy)?
Term used to describe liver disorders that occur due to right sided heart failure
Includes:
-Hepatomegaly
-Portal-hepatic venous system + IVC dilation with absence of wall motion with respiration
-Pulsatile PV flow (antegrade + retrograde)
-HV waveform has very pulsatile “W” type pattern
What causes primary + secondary BCS?
Primary: endoluminal thrombus or webs
Secondary: malignant tumor, etc
SF of BCS?
-Dilated HVs or IVC
-Stenosis or occlusion of HVs or IVC
-Absence of flow in HVs or IVC
-Slow or reversed flow in PV
-Enlarged caudate lobe (>3.5cm)
-Enlarged caudate vein (>3mm)
SF of SOS?
Patent + large HVs and PVs
TIPS is done under ___ guidance?
Fluroscopic
Where does the catheter get inserted with TIPS insertion?
Enters RJV, through wall of RHV, then through liver to get to the RPV
TIPS reroutes blood from the ___ to ___?
From RPV to RHV + back to IVC
What type of flow should a functioning TIPS have?
-Hepatopetal flow in MPV
-Hepatofugal flow in intrahepatic PV branches, beyond the stent
SF of TIPS?
2D:
Echogenic structure around hepatic parenchyma that extends into the PV + RHV
CD:
-Hepatopetal flow at PV end
-Hepatofugal flow at HV end
Normal velocities within a TIPS stent range from ____?
90-190 cm/s
(take velocity at MPV, PV end, midstent, HV end + HV outflow)
What velocity would indicate a TIPS stenosis?
> 190 cm/s
SF of a TIPS occlusion?
-Echogenic material within stent
-Absent flow with spectral + CD
