Portal Hypertension · IR Playbook

Direct Intrahepatic Portocaval Shunt (DIPS)

DIPS is the percutaneous creation of a side-to-side portocaval shunt through the caudate lobe, connecting the retrohepatic inferior vena cava directly to the portal vein under intravascular ultrasound guidance. The mechanism is identical to TIPS — diversion of portal inflow into the systemic circulation lowers the portosystemic gradient and therefore variceal wall tension and ascites formation — but the outflow is the IVC rather than a hepatic vein, which is why it remains feasible when the hepatic veins are occluded or unusable. The tract through the caudate lobe is short and largely extraparenchymal at the caval end, so real-time IVUS rather than blind fluoroscopic throw is what makes the puncture safe. Because the shunt physiology is the same as TIPS, so is the complication profile: hepatic encephalopathy and hepatic insufficiency dominate, with the added specific hazard of extracapsular puncture into the peritoneum or retroperitoneum given the caudate lobe's anterior surface relationships.

Learning objectives

• Select patients for DIPS rather than conventional TIPS on the basis of hepatic venous outflow anatomy and portal vein status.
• Identify on IVUS the retrohepatic IVC, caudate lobe and portal vein relationship that defines a safe puncture window.
• Perform the IVUS-guided transcaval puncture and recognise when the trajectory has left the parenchyma.
• Size and land the stent-graft so that the covered segment bridges the full portocaval tract without protruding into the right atrium or occluding portal branches.
• Recognise and manage retroperitoneal or intraperitoneal haemorrhage, caval injury and post-shunt encephalopathy.

Indications

• Budd-Chiari syndrome with hepatic vein occlusion where conventional TIPS is not feasible and medical therapy or recanalisation has failed.
• Complications of portal hypertension when hepatic vein anatomy is unusable — absent, diminutive, thrombosed or unfavourably angled hepatic veins.
• Failed conventional TIPS after repeated unsuccessful hepatic vein to portal vein puncture attempts.
• Portal vein thrombosis requiring shunting where a short direct caval-to-portal tract is more achievable than a hepatic venous route.
• Refractory ascites or refractory hepatic hydrothorax in patients whose hepatic venous outflow precludes standard TIPS.
• Variceal haemorrhage refractory to endoscopic and pharmacological therapy in the same anatomical circumstances.

Absolute contraindications

• Occluded or unusable retrohepatic inferior vena cava with no available outflow segment.
• Severe right or left heart failure and severe pulmonary arterial hypertension.
• Uncontrolled systemic or biliary sepsis.
• Diffuse hepatic tumour or polycystic disease occupying the caudate lobe tract.

Relative contraindications

• Persistent overt hepatic encephalopathy despite therapy.
• Very advanced liver failure, for example MELD above 18-20 or bilirubin above 3 mg/dL in the elective setting.
• Marked caudate lobe hypertrophy, common in Budd-Chiari syndrome, which lengthens and distorts the tract.
• Extensive portal vein thrombosis with cavernoma.
• Uncorrectable severe coagulopathy or profound thrombocytopenia.
• Hepatocellular carcinoma along the intended tract.

Equipment

• Ultrasound machine with vascular probe for jugular and femoral access
• 18 G access needles, 0.035 inch J wires, 10 Fr long vascular sheath for the jugular route and 8-9 Fr sheath for the femoral route
• Phased-array intravascular ultrasound catheter and console
• Dedicated transjugular liver access set with curved metal cannula and 16 G Rosch-Uchida or Colapinto-type needle system
• 0.035 inch hydrophilic guidewire and 260 cm stiff exchange wire
• 5 Fr pigtail or marker pigtail catheter for portal venography and tract measurement
• 6-10 mm high-pressure angioplasty balloons
• PTFE-covered stent-graft, 8 or 10 mm diameter, with short covered lengths available for the short caudate tract
• Pressure transducer and manifold for right atrial, caval and portal pressure measurement
• Microcatheter, coils and sclerosant or glue for adjunctive variceal embolisation
• Covered stent-graft of caval diameter available as a bailout for IVC injury

Procedure steps

1. Under ultrasound guidance puncture the right internal jugular vein and place a 10 Fr long sheath into the IVC, and puncture the right common femoral vein and place an 8-9 Fr sheath. Two access points are required because the imaging catheter and the puncture system must approach the same level from opposite directions.
2. Record right atrial pressure with the transducer zeroed at the mid-axillary line, and record retrohepatic IVC pressure. The atrial value is the systemic reference for the portosystemic gradient; a caval pressure substantially higher than atrial indicates caval compression by a hypertrophied caudate lobe, which alters the gradient you will be targeting.
3. Perform a retrohepatic cavogram to confirm caval patency, define the degree of any extrinsic compression, and mark the intrahepatic caval segment fluoroscopically. A significantly narrowed or webbed IVC may itself require angioplasty or stenting before or after shunt creation.
4. Advance the IVUS catheter from the femoral sheath into the retrohepatic IVC and withdraw slowly, identifying the portal vein and its bifurcation anterior to the caval lumen. Choose the level at which the portal vein is closest to the IVC with unequivocal caudate parenchyma between them, and mark that level fluoroscopically; if no such level exists, the procedure should not proceed to puncture.Pearl: Rotate the IVUS transducer to place the portal target at a known clock position on the image, then align the needle curve to the same clock position, so the throw direction is defined by the image rather than by assumption.
5. Advance the curved metal cannula from the jugular sheath to the marked caval level and rotate the curve anteriorly toward the target identified on IVUS. Verify on the IVUS image that the cannula tip indents the caval wall at the intended clock position before any needle is advanced.
6. Advance the 16 G needle across the caval wall and through caudate parenchyma toward the portal vein while watching the needle tip echo on IVUS, then withdraw slowly under gentle aspiration. Because the tract is short, the throw is correspondingly short — typically 2-4 cm — and overshooting carries the needle through the portal vein and out of the liver. Confirm portal entry with dark non-pulsatile blood return and a hand injection showing hepatopetal portal branches; abandon the pass immediately for biliary radicles, arterial pulsation or a parenchymal blush.Pearl: General anaesthesia with controlled ventilation keeps the target immobile between IVUS localisation and the throw, which matters more here than in conventional TIPS because the working distance is so short.
7. Advance a hydrophilic wire deep into the splenic or superior mesenteric vein and exchange for a marker pigtail catheter. Perform portal venography to define the exact portal entry point, opacify varices, and measure the tract length from portal entry to caval entry, which determines the covered stent length.
8. Record direct portal vein pressure and subtract right atrial pressure. Use the atrial rather than the caval value as the reference when the IVC is compressed, otherwise a compressed caval pressure will make the gradient appear falsely low and lead you to under-treat.
9. Exchange for a stiff 260 cm wire and dilate the tract with a 6-8 mm balloon, observing the waists that mark the caval and portal entry points. These two waists define the landing zones for the covered segment across a tract that may be only a few centimetres long.
10. Deploy a PTFE-covered stent-graft so the covered portion bridges the entire caudate tract from portal vein entry to caval entry, with the uncovered or portal-end segment within the portal vein. Watch both ends during unsheathing: the device must not protrude into the right atrium cranially nor overhang and occlude the contralateral portal branch, and a short tract leaves very little margin for either error.Pearl: Select the shortest covered length that spans the measured tract; using a standard long TIPS device across a short caudate tract is the commonest cause of atrial or portal protrusion.
11. Dilate the stent to 8 mm, repeat portography and remeasure the portosystemic gradient. Dilate toward 10 mm if the target gradient is not met; accept an underdilated shunt if the gradient falls excessively in a patient at high encephalopathy risk.Pearl: Underdilating an 8 mm covered stent-graft titrates decompression while retaining the option to dilate further at a later session.
12. If varices still opacify on the completion portogram despite an adequate gradient, catheterise the feeding vein with a microcatheter and embolise with coils, with or without sclerosant or glue.
13. Perform a final portogram and a cavogram to document shunt flow, stent position and an uninjured, patent IVC. Remove both sheaths and achieve haemostasis by manual compression at the jugular and femoral sites.

Complications

• Retroperitoneal or intraperitoneal haemorrhage
• Inferior vena cava injury
• Hepatic encephalopathy
• Acute-on-chronic liver failure
• Shunt dysfunction
• Haemobilia and biliary-shunt fistula
• Hepatic artery injury or arterioportal fistula
• Cardiac decompensation and pulmonary oedema
• Stent malposition into the right atrium
• Shunt infection (endotipsitis)

Exam pearls

• A direct intrahepatic portocaval shunt creates a side-to-side portocaval connection through the caudate lobe between the retrohepatic IVC and the portal vein, and is chosen when the hepatic veins are occluded, absent or unusable.
• Part of the retrohepatic inferior vena cava is not surrounded by liver, which is why intravascular ultrasound is used to confirm interposed caudate parenchyma before the needle throw — a puncture from a bare caval segment enters the retroperitoneum.
• The caudate lobe drains directly into the IVC by short veins rather than through the main hepatic veins, which is why it hypertrophies in Budd-Chiari syndrome and why it remains perfused when the hepatic veins occlude.
• In a caudate-compressed inferior vena cava, the portosystemic gradient must be calculated against right atrial pressure; using retrohepatic caval pressure gives a falsely low gradient and under-treatment.
• The DIPS tract is only about 2-4 cm long, so a standard-length TIPS stent-graft will overshoot into the right atrium or the main portal vein — the covered length must match the measured tract.
• The classical DIPS technique uses dual access: a jugular sheath for the needle system and a femoral sheath for the intravascular ultrasound catheter, so that imaging and puncture approach the target from opposite directions.

Viva questions

Why does DIPS pass through the caudate lobe specifically, rather than any other segment?

Because the caudate lobe sits directly between the retrohepatic IVC posteriorly and the portal vein bifurcation anteriorly, giving the shortest path from cava to portal vein that stays entirely within liver parenchyma. Any other trajectory from the IVC to the portal vein leaves the liver and enters the peritoneum or retroperitoneum.

You have a Budd-Chiari patient with a compressed retrohepatic IVC and a measured gradient of 9 mmHg using caval pressure as the reference. Do you stop?

No — the reference is wrong. Caudate hypertrophy has raised the retrohepatic caval pressure, so subtracting it understates the true portosystemic gradient. Recalculate against right atrial pressure, and if caval compression is significant, treat the caval outflow with angioplasty or stenting, since the shunt cannot decompress into an obstructed cava.

Why is IVUS mandatory here when conventional TIPS can be done with wedged CO2 portography alone?

In TIPS, the hepatic vein origin guarantees the needle starts inside liver parenchyma, so a mapped fluoroscopic throw is reasonably safe. In DIPS the needle starts in the IVC, part of whose retrohepatic course is bare and not surrounded by liver, so only real-time imaging can confirm there is caudate parenchyma between the transducer and the target before the throw. Without that confirmation the puncture goes into the retroperitoneum.

Why is the throw shorter than in conventional TIPS, and what happens if you forget?

The caudate tract is typically only 2-4 cm, against a much longer hepatic vein to portal vein tract. A conventional-depth throw overshoots through the portal vein and out of the anterior caudate surface into the peritoneal cavity, causing intraperitoneal haemorrhage.

A DIPS patient is a transplant candidate. What device-related point must you document?

Whether the cranial stent end protrudes into the right atrium or beyond the caval-atrial junction. A transcaval device that extends into the atrium compromises caval reconstruction during hepatectomy, so the surgical team must know before listing, and this is why the covered length is chosen to the measured tract rather than by default.

Six months after DIPS for Budd-Chiari, the shunt occludes abruptly. What is the likely mechanism and how does it differ from post-TIPS dysfunction in cirrhosis?

Thrombosis driven by the underlying thrombophilia, rather than the gradual pseudointimal hyperplasia typical of cirrhotic TIPS dysfunction. It presents abruptly rather than as slowly recurring ascites, and management includes thrombectomy or thrombolysis plus a review of anticoagulation intensity, not angioplasty alone.

Two accesses are used. Justify each.

The jugular sheath carries the curved cannula and needle inline down the IVC, giving a workable anterior throw angle. The femoral sheath carries the IVUS catheter cranially so the transducer sits at the puncture level and images the target from below while the needle advances from above. Combining them into one access would put the imaging and the puncture on the same axis and lose real-time visualisation of the needle approaching the target.

When would you choose IVUS-guided conventional TIPS over DIPS?

Whenever a hepatic vein is patent and usably angled but the portal target is simply hard to hit fluoroscopically. IVUS solves the aiming problem without committing to a transcaval tract, which avoids caval wall injury and the atrial-protrusion and caval-reconstruction issues that DIPS introduces.

References