13.4 Hepatoportal Hemodynamics & TIPS Surveillance
Key Takeaways
Portal inflow is hepatopetal; hepatic venous outflow toward the heart is hepatofugal.
Hepatic venous S/D flow generally goes toward the heart; atrial contraction can briefly reverse flow toward the liver.
Portal hypertension and Budd-Chiari require integrated findings; one diameter, velocity, or waveform is not independently definitive.
TIPS assessment includes portal inflow, shunt entry/body/outflow, draining veins, clinical symptoms, and baseline comparison.
Abnormal TIPS velocities are screening clues; suspected dysfunction may require venography/pressure assessment rather than automatic revision.
Establish normal flow directions
The portal vein carries blood from the splanchnic circulation toward the liver: hepatopetal flow. The hepatic artery supplies arterial inflow and normally has sustained forward diastolic flow. The hepatic veins drain blood away from the liver toward the IVC and heart: hepatofugal outflow. These words refer to the liver, not to the probe. Red/blue color and above/below-baseline position depend on the display orientation and must not substitute for anatomic direction.
The main portal vein forms from the splenic and superior mesenteric veins. Trace its branches where accessible and assess lumen, flow direction, velocity, respiratory variation, and surrounding anatomy. Normal portal velocity varies with sampling site, respiration, meals, posture, and measurement method. A single diameter or velocity threshold cannot diagnose every case of portal hypertension.
Hepatic venous waveforms
Hepatic venous pulsatility reflects right atrial events. The S and D components generally carry blood toward the heart, while atrial contraction can cause a brief a-wave reversal toward the liver. A smaller transitional v component may also be present. Because several components occur, the familiar term “triphasic” describes the overall pattern rather than a strict count of every deflection.
Flattening of the waveform is nonspecific. Liver disease, respiratory technique, cardiac conditions, and postoperative anatomy can change pulsatility. Prominent reversal during ventricular systole can occur with severe tricuspid regurgitation. Identify timing and direction instead of treating every reversal as the same mechanism. Transplant reconstructions require their own context and are covered in the transplant section.
Portal hypertension and collateral pathways
Portal hypertension can arise before, within, or after the liver. Cirrhosis is a common intrahepatic cause; portal thrombosis is a prehepatic mechanism, and hepatic venous outflow impairment is another important differential. Ultrasound can show slow or reversed portal flow, collateral vessels, splenomegaly, ascites, and parenchymal changes. No one of these findings is required or independently diagnostic in every patient.
A paraumbilical collateral can connect the left portal system through the falciform/ligamentum teres region to abdominal-wall veins, carrying hepatofugal portal-system drainage. Left gastric and splenorenal/gastrorenal pathways are other collaterals. Trace the vessel and its connections to distinguish collateral flow from an adjacent artery or artifact. Do not assign “100% specificity” to an arbitrary collateral diameter or velocity.
Portal vein thrombosis may be partial or complete. Search for intraluminal material and evaluate residual flow with suitably low scale and filter. Cavernous transformation consists of collateral channels around an obstructed portal segment; it supports an established obstruction but does not provide an exact date of onset. Tumor-associated intravascular tissue can have internal arterial flow and requires further assessment rather than automatic classification as bland thrombus.
Budd-Chiari syndrome concerns hepatic venous outflow obstruction. Evaluate the hepatic veins and accessible IVC for narrowing, thrombus, altered direction, and collateral pathways. Caudate enlargement can occur because of its different venous drainage, but is not pathognomonic. An invisible hepatic vein in a difficult window is not proof that it is thrombosed.
TIPS anatomy and acquisition
A transjugular intrahepatic portosystemic shunt (TIPS) commonly connects a portal branch to a hepatic vein, providing a lower-resistance path to systemic venous outflow. Review the procedure, device, baseline, indication, and recurrent symptoms. Covered devices and older bare stents differ; do not treat every historical velocity rule as equally validated in contemporary covered TIPS.
Examination checklist
- Image the main portal vein and accessible branches, documenting direction and representative velocity.
- Trace the shunt from portal entry through its body to hepatic venous outflow.
- Obtain spectral samples at reproducible inflow, mid-shunt, and outflow locations.
- Assess accessible draining hepatic vein/IVC and surrounding liver.
- Compare shunt velocities, portal flow direction, ascites, and other findings with baseline.
- State technical limitations and communicate concerning changes.
Flow through a functioning shunt is directed toward systemic outflow. Intrahepatic portal branches may reverse toward the shunt entry; interpretation depends on the actual reconstruction and baseline. Spectral velocity varies along the device, and a curved shunt can create difficult Doppler angles. Confirm representative measurements before reporting a focal change.
Suspected dysfunction
Focal acceleration with visible narrowing, a new low-flow state, absent optimized shunt signal, or a significant interval change can suggest dysfunction. Historically cited ranges such as 90–190 cm/s and changes around 50 cm/s are screening clues in some protocols, not universal proofs of a ≥50% stenosis. Covered-stent performance and the complete clinical context matter.
Recurrent ascites or variceal bleeding strengthens concern and should prompt timely assessment by the treating team. Venography with pressure measurements may be needed to confirm dysfunction and guide revision. Duplex cannot determine the portosystemic pressure gradient directly or prescribe revision from one velocity threshold.
Worked interpretation
A patient develops recurrent ascites and a focal outflow velocity of 245 cm/s, compared with a lower baseline. This combination is concerning for shunt dysfunction. Verify the angle and focal anatomy, record the full shunt and portal findings, and communicate promptly. The proper conclusion is suspected dysfunction requiring clinical evaluation, not a guaranteed percentage stenosis or an automatic balloon-angioplasty order.
AASLD guidance describes covered-TIPS Doppler follow-up commonly at 1–4 weeks, 3 and 6 months, then every six months, with modification for symptoms and individual circumstances. Do not call a 24–48-hour scan a universal IAC requirement. Follow the treating service's protocol and recognize that symptoms can require evaluation before any scheduled surveillance date.
AASLD TIPS practice guidance — checked October 18, 2026.
A 54-year-old male with alcoholic cirrhosis undergoes duplex surveillance 6 months after receiving an ePTFE-covered TIPS stent. The patient reports a 10-pound weight gain and worsening abdominal distension. Duplex ultrasound reveals an in-stent Peak Systolic Velocity of 245 cm/s with marked spectral broadening at the hepatic vein outflow junction, and a main portal vein velocity of 22 cm/s. How should this study be categorized and clinically managed?
Normal function is proven
Suspected TIPS dysfunction: verify and communicate the new focal outflow change with recurrent ascites for clinical evaluation
Acute rejection is proven
A velocity of 245 excludes stenosis
A 49-year-old female with decompensated hepatitis C cirrhosis presents for portal duplex evaluation. Gray-scale imaging demonstrates a shrunken, nodular liver, marked ascites, and a spleen measuring 16.5 cm. Color and spectral Doppler interrogation of the ligamentum teres reveals a patent, tortuous 5 mm tubular channel carrying continuous blood flow directed toward the anterior abdominal wall with a velocity of 62 cm/s. What specific portosystemic collateral pathway has been identified?
Retrograde left gastric (coronary) vein feeding esophageal varices.
Left renal vein compression consistent with Nutcracker syndrome.
A recanalized paraumbilical vein demonstrating hepatofugal flow toward the anterior abdominal wall (Cruveilhier-Baumgarten syndrome).
A spontaneous splenorenal shunt decompressing the superior mesenteric vein.
A 36-year-old female with polycythemia vera presents with severe acute right upper quadrant pain, tender hepatomegaly, and rapid accumulation of tense ascites. Duplex ultrasound demonstrates non-visualization of the right and middle hepatic veins, a thin cord-like left hepatic vein with complete absence of color flow, marked hypertrophy of the caudate lobe, and a patent main portal vein with sluggish hepatopetal flow (12 cm/s). What condition is established by these findings, and why is the caudate lobe hypertrophied?
Acute portal vein thrombosis; the caudate lobe hypertrophies because it receives arterial blood from the left gastric artery.
Cirrhotic sinusoidal obstruction; the caudate lobe hypertrophies due to increased gastrointestinal glycogen absorption.
Pelvic congestion syndrome; the caudate lobe hypertrophies due to collateral ovarian drainage.
Budd-Chiari syndrome; the caudate lobe hypertrophies because its independent emissary veins drain directly into the IVC, sparing it from outflow obstruction.
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