Advanced Imaging Techniques Used in Direct Portosystemic Shunt Creation in Budd-Chiari Syndrome with Complex Venous Anatomy

Clinical Presentation

Budd-Chiari syndrome (BCS) is a relatively rare disease, most commonly found in middle-aged females, and is caused by hepatic vein blockage, except in Asian countries where it is more commonly found in males with inferior vena cava (IVC) obstruction. ¹ The condition is classified as either primary or secondary depending on the source of the obstruction and whether it originates from within the venous system, such as in thrombosis, or external to the venous system, such as in compression by tumors of adjacent organs or polycystic kidney disease. Primary BCS is the most common manifestation and is most prevalent in those with underlying thrombogenic disorders such as primary myeloproliferative disease, essential thrombocythemia, and myelofibrosis. ² Conditions that result in hypercoagulability such as pregnancy, oral contraceptive use, factor V mutation, antithrombin deficiency, protein C deficiency, and paroxysmal nocturnal hemoglobinuria can also cause primary BCS. ³ However, in most cases, the local cause of the thrombus formation cannot be identified.

BCS generally becomes clinically evident after the occlusion of two or more major hepatic veins ( Figs. 1 and 2 ). This causes a build-up of sinusoidal pressure and increased filtration of interstitial fluid into the liver capsule after the capacity of lymphatic drainage capacity has been exceeded. Resulting portal hypertension causes reduced hepatic blood flow and hepatocyte damage. ² BCS and its progression can range in severity from asymptomatic, unobtrusive disease to acute, debilitating disease with significant morbidity. ^{4 5} When symptomatic, BCS can present with abdominal pain and/or distention, ascites, hepatomegaly, jaundice, upper gastrointestinal bleeding, hepatic encephalopathy, and edema. ⁴ In chronic cases, patients can also present with renal impairment. ¹

Fig. 1.

A 20-year-old woman with a history of sickle cell disease, Jak2 mutation, and BCS with refractory ascites and hepatorenal syndrome. Contrast-enhanced CT ( a ) shows a very large caudate lobe (solid arrows). There is a nubbin of the hepatic vein (solid arrow, b ) on the CT image. Percutaneous access (dotted arrow, c and d ) is obtained in the left portal vein and portal venography is performed showing patent intrahepatic portal vein branches. The hepatic vein nubbin is used to engage the access needle in the IVC which is advanced to the portal vein (solid arrow, d ) and wire is advanced into the portal vein (arrowhead, d ). Portal venography with a marking pigtail catheter is performed to measure the distance for stenting ( e ). Often more than one stent is required to cover the parenchymal distance. Final portal venography showing patent DIPS stent (dotted arrows, f ).

Fig. 2.

A 19-year-old woman with a past medical history of Evans syndrome, antiphospholipid antibodies, and systemic lupus erythematosus with BCS and refractory ascites and abdominal pain. Contrast-enhanced axial CT ( a ) image shows nutmeg appearance of the liver (solid arrow), and a large amount of ascites. The intrahepatic IVC is not visualized (asterisk on the expected location, b ).

Endovascular Treatments for Budd-Chiari

Transjugular Intrahepatic Portosystemic Shunt Creation

Treatment for BCS is primarily composed of restoring normal hepatic venous outflow, preventing liver deterioration, and treating the underlying condition. Removal of the venous obstruction can be completed via thrombolysis or stenting. ⁶ In cases of acute BCS that fail to respond to reperfusion of the occluded vessel, a transjugular intrahepatic portosystemic shunt (TIPS) can be used to relieve sinusoidal pressure. ⁷ There is a paucity of data on the best time to prescribe portosystemic shunt creation in BCS patients, but some studies favor early intervention. ⁸ TIPS is considered a safe and efficient treatment to treat patients with BCS presenting with sequela of portal hypertension. ⁹ When the right or middle hepatic vein is patent, it can be used as access to create TIPS in BCS patients. In such patients, both conventional and intravascular ultrasound (IVUS)-guided TIPS creation can be considered. Cone beam computed tomography, ¹⁰ intracardiac echocardiography (ICE), ¹¹ a three-dimensional (3D) virtual target fluoroscopic display ¹² can improve the visualization and access portal vein branches during TIPS creation in these patients with complex anatomy. In some cases, opacification of the portal vein via a percutaneous transhepatic, trans-splenic, or para-umbilical vein is used as an additional tool to improve the success rate in accessing the portal vein. A detailed review of such techniques is available in this volume. ¹³ In this article, alternative advanced techniques to create a direct portosystemic shunt (DIPS) in BCS patients with complex venous anatomy are discussed in more details.

Direct Portosystemic Shunt Creation

In cases where there are anomalies of the hepatic or portal venous system, such as significant hepatic venous stenosis, intrahepatic portal thrombosis, venous distortion from prior hepatic resections, or severely angulated hepatic veins, a TIPS may not be possible and direct shunt between the portal vein and IVC can instead be attempted. ^{14 15} In such cases, this is accomplished by either a DIPS or a transjugular transcaval intrahepatic portosystemic shunt.

Transjugular Approach

In cases with diminutive hepatic veins or when there is nubbin left at the origin of hepatic veins, DIPS creation may be attempted under fluoroscopy guidance. Preoperative review of venous anatomy on the CT or magnetic resonance imaging is essential. A real-time percutaneous or IVUS may provide more information about the anatomy.

The cannula can be engaged into the hepatic vein nubbin in the IVC, and the needle can be advanced under fluoroscopic guidance ( Fig. 1 ). Portal vein can be accessed percutaneously using transhepatic, trans-splenic, or para-umbilical veins under ultrasound guidance. The access site is dilated to accept a 5-Fr sheath. Portal venography can be performed in multiple directions and used for triangulation when advancing the needle from the transjugular approach. Once access is obtained in the portal vein, gentle contrast injection can confirm the intravascular position. A guidewire is advanced into the portal vein to maintain access. Initial portal venography and pressure measurement are performed. The parenchymal tract is dilated using 8- to 10-mm balloons to advance the sheath to the portal vein in preparation for stent placement. Compared to TIPS creation, parenchymal dilation, and sheath advancement from IVC to portal vein may be more difficult, and additional maneuvers including spinning the sheath, using the inner dilator, or multiple balloon dilation may be needed. The length of stenting is often longer than commercially available stents and two to three overlapping Viator stents (Gore, Flagstaff, AZ), or a combination of uncovered and covered stents may be needed ( Fig. 1 ). The cranial end of the stent should project into the IVC; this contrasts with the TIPS creation where the optimal position is at the hepato-caval junction. The stent is dilated using 8- to 10-mm balloons depending on the final pressure gradient and the blood flow status.

Percutaneous Approach

In cases with complete obstruction of the hepatic veins, there may not be a nubbin at the IVC to engage the cannula ( Fig. 2 ). In such cases, simultaneous direct percutaneous access of the portal vein and IVC may be beneficial. ¹⁶ Percutaneous ultrasound can be used as the primary tool to guide direct simultaneous access into the portal vein and the IVC. ¹⁶ A combination of the percutaneous and IVUS provides a better assessment of hepatic and portal vein branches and can guide percutaneous puncture into the IVC and the portal vein as well as stent placement.

Combined Percutaneous and Intravascular Ultrasound Guidance

The procedure is performed under general anesthesia. Under ultrasound guidance, an access is obtained into the right internal jugular (IJ) vein to accept a 10-Fr sheath. In cases without an IVC stenosis or obstruction, a second IJ access can be obtained. When there is IVC narrowing or obstruction, access should be obtained into the right femoral vein. The second access is used for IVUS and is upsized to accept a 9-Fr sheath. Through the 9-Fr sheath, an ICE probe is advanced into the IVC. IVUS can be used to evaluate the hepatic and portal venous anatomy for planning purposes.

Through the IJ access, a balloon is advanced into the intrahepatic IVC and is used as a target for the portocaval access. For percutaneous access, the left portal vein provides better angulation for dual portocaval puncture and is often preferred. ¹⁶ The left portal vein should be accessed at the segment between the main portal vein take-off and before dividing into segmental branches. Through an epigastric percutaneous approach, the right or left portal vein is accessed using a 21-gauge needle under percutaneous US guidance. The needle is directed to puncture the inflated balloon in the intrahepatic IVC under the US and fluoroscopy guidance ( Fig. 3 ). The balloon is then deflated and withdrawn through the neck sheath. Contrast injection can confirm the position of the needle tip in the IVC. A 0.018-microwire is advanced through the needle into the IVC and is snared through the jugular sheath to complete through-and-through portosystemic access. The appropriate access site at the portal and IVC ends can be confirmed by the IVUS. The percutaneous access is dilated to accept a 5-Fr sheath and the microwire is exchanged for a 0.035 working guidewire like Amplatz (Amplatz, Boston Scientific). The percutaneous sheath is advanced into the portal vein, and a portal venogram is performed and used as a reference.

Fig. 3.

Same case as in Fig. 2 . Transabdominal US ( a ) shows the left portal vein (dotted arrow) and an inflated balloon in the IVC (solid arrow) as potential access. Initial cavogram ( b ) demonstrates severe luminal narrowing of the IVC (solid arrows). A 21-G needle (dotted arrow, c ) is advanced under US and fluoroscopic guidance to puncture the balloon (solid arrow, c ) in the IVC. Initial portal venography shows a patent portal vein, percutaneous access in the left portal vein (marking pigtail, d ), and a percutaneous through-and-through access (dotted arrows, d and e ). Simultaneous balloon inflation in IVC (dotted arrow, f ) and DIPS (solid arrow, f ) stents to prevent stent dislodgment. Final venography shows patent IVC (dotted arrow, g ) and DIPS (solid arrow, h ) stents. The gastroesophageal varices are embolized with coils and plug (asterisk d and h ). L: left portal vein, M: main portal vein.

Through the transjugular access, the hepatic parenchymal tract is dilated using an 8-mm balloon up to portal vein access under IVUS and fluoroscopic guidance. The balloon is deflated slowly, and the 10-Fr sheath is advanced into the portal vein. A hydrophilic catheter and stiff glidewire (Terumo, Somerset, NJ) are advanced coaxially, beside the Amplatz wire, and used to select the main portal vein. A marking pigtail catheter is placed into the splenic vein and venography is performed to assess the portal vein, and possible gastroesophageal varices and to perform measurements for DIPS stent placement ( Fig. 3 ). This access is then used to place Viatorr stent (Gore) between the portal vein and IVC. Real-time visualization by IVUS is very helpful for more accurate deployment of the stent, particularly in cases with diminutive portal vein branches. Final portal venography and pressure measurement are done to assess the patency of the portal vein and stent and hemodynamic status. The percutaneous access can be closed using Gelfoam (Pfizer, New York, NY) or n-butyl-2-cyanoacrylate (n-BCA) liquid embolic system (Trufill, Cordis).

In BCS cases with symptomatic concurrent IVC stenosis, angioplasty and stenting of the IVC may be required. Palmaz XL (Cordis, Santa Clara, CA) and Z stent (Cook Medical, Bloomington, IN) are two available uncovered stents with acceptable radial forces for IVC stenosis. If an IVC stent is planned, it is advised to inflate an 8- or 10-mm balloon in the DIPS stent to prevent stent dislodgement or occlusion during deployment of the IVC stent (double-balloon technique) ( Fig. 3 ).

Postprocedure Care

Stent dysfunction and the need for revision are not uncommon in BCS patients undergoing portosystemic shunt creation and these patients should be monitored carefully on early postprocedural days. ⁹ These patients are often on blood thinners and should be restarted on blood thinners after the procedure to lower the chance of portal vein or DIPS stent thrombosis. The potential complications of percutaneous DIPS creation include capsular bleeding, intraperitoneal bleeding, hepatic encephalopathy, infection, death, and risk for rethrombosis, particularly in cases with prothrombotic syndromes. ¹⁷ Endovascular thrombectomy or thrombolysis may be considered when there is portal vein and stent thrombosis ( Fig. 4 ). Stent angioplasty and extension may be needed in cases with stent narrowing or inadequate coverage. The IVC end of the stent is the most common area of stenosis. The IVC segment above the DIPS stent should be well evaluated for possible stenosis which may require venoplasty with or without stent placement.

Fig. 4.

The same patient as in Fig. 3 presented with complete thrombosis of the main portal vein (solid arrow, a ), DIPS stent (dotted arrow, a ), and partial thrombosis of IVC (not shown). The patient underwent mechanical (solid arrow, b ) and pharmacological thrombectomy and thrombolysis. A protective sheath was placed in the suprahepatic IVC to prevent clot migration to the heart (dotted arrow, b ). Follow-up imaging 5 months after the procedure shows more homogenous enhancement of the liver (solid arrow, c ), patent DIPS (solid arrow, d ), and IVC stents (dotted arrow, c and d ).

Meticulous evaluation of the venous anatomy by IVUS plays an important role in procedural planning. IVUS can be used to better assess the anatomy of portal vein, hepatic veins, and IVC. In BCS cases with complex venous anatomy, IVUS can provide information that may not be easily available by computed tomography or fluoroscopy. Variant anatomy including accessory hepatic veins can be seen by IVUS and may be used as a target for portosystemic shunt creation. In percutaneous DIPS creation, IVUS can confirm appropriate access into the portal vein branch and the IVC and is helpful for more accurate stent deployment. IVUS is an efficient assistant tool for TIPS creation, ¹¹ and is associated with less procedure time, radiation dose, contrast usage, and fewer needle passes. ¹⁸ In summary, real-time inspection of the anatomy and planning for potential shunt pathways by IVUS is more critical in patients with complex anatomy, where conventional fluoroscopy-guided techniques may not be helpful.