A standard transjugular approach with real-time transabdominal or intravascular ultrasound guidance remains one of the preferred approaches to TIPS in chronic PVT (Figure 1, Figure 2 and Figure 3). Simultaneous ultrasound guidance allows the operator to access the thrombosed native portal vein. Use of this route not only reduces the procedure time and associated risks of prolonged radiation exposure but avoids several other potentially life-threatening complications of TIPS such as capsular transgression and hemoperitoneum, inadvertent puncture of an artery or periportal collateral vessels, biliary injury, and access site complications (in cases of transhepatic or trans-splenic approach) ^[1][17]. The need for an extra set of expert hands for ultrasound guidance and unfavorable body habitus in some patients remains a drawback. Moreover, the thrombosed or fibrotic intrahepatic branch of the native portal vein should be visible on the ultrasound for this approach to work. The fluoroscopy-guided puncture of the non-visualized fibrotic portal vein from the transjugular approach has found limited technical success.

Initial attempts at TIPS in patients with portal vein thrombosis utilized the transhepatic approach ^[2][14]. Briefly, a micropuncture set is used to access the thrombosed portal vein under fluoroscopic or ultrasound guidance. After balloon dilatation and thrombus aspiration from the portal vein, an inflated contrast-filled balloon or vascular snare is placed, which can be used as a target to puncture the portal vein from the transjugular approach. The rest of the procedure is completed from the jugular side in the standard fashion. The transhepatic tract is plugged with gel foam, coils, or glue. In patients with concomitant chronic thrombosis of hepatic veins (chronic Budd–Chiari Syndrome), this approach can be modified by simultaneously puncturing the thrombosed portal vein and the inferior vena cava (IVC) and snaring the guidewire from IVC through the jugular route (Figure 4).

The tract between the portal vein and IVC is then balloon dilated, and the portal vein is accessed from the jugular approach to stent deployment. The advantage of the transhepatic approach is that accessing the portal system via this shorter route through the liver under image guidance is considered relatively easier compared to the longer transjugular route wherein a longer needle has to be manipulated through the metallic cannula. However, concern for access site complications remains, especially in patients with coagulopathy and ascites. With the advent of intravascular ultrasound and the trans-splenic approach, the transhepatic route is less commonly utilized.

A significant proportion of patients with portal cavernoma do not have a visible native portal vein on imaging. Thus, alternative routes had to be devised for the placement of TIPS. The trans-splenic approach remains the mainstay for such patients. Originally described in the late 1980s, the trans-splenic route was traditionally associated with high rates of hemorrhagic complications ^[3][18]. However, with improved imaging and real-time ultrasound guidance, complication rates directly attributable to the splenic puncture became low ^[4][19]. The trans-splenic route is considered ideal when there is a large patent splenic vein with one of its branches entering the splenic parenchyma in a direct anatomic or straight line ^[5][20]. This intraparenchymal branch is punctured under ultrasound guidance using a micropuncture set. A guidewire and catheter combination are then used to probe and access the fibrotic portal vein via an antegrade approach. The technique requires repeated probing with multiple different catheters at the splenoportal confluence to succeed. After recanalizing the portal vein, a contrast-filled balloon or vascular snare can be placed within the third-order portal vein, which can be targeted via the transjugular route using fluoroscopic triangulation to get the guidewire into the portal vein from the jugular side. This guidewire is snared from the trans-splenic access route to create through-and-through access (Figure 5).

The rest of the procedure is completed via neck using a standard technique. The trans-splenic access site is plugged in to avoid bleeding complications. This approach can also be used in patients with partial thrombosis of the splenic vein at the splenoportal confluence in whom accessing the splenic vein from the transjugular route is difficult (Figure 6).

Recent studies have described the percutaneous transmesenteric approach to access the portal vein via the antegrade route ^[6][7][21,22]. For patients in whom primary transjugular, transhepatic, or trans-splenic approaches fail due to chronically thrombosed splenic veins with non-visualization of intrahepatic native portal vein branches or those who have undergone splenectomy, this route can be utilized. A 21-G needle is used to access the superior or inferior mesenteric vein via the transabdominal route under ultrasound guidance. A guidewire and catheter combination are then used to catheterize the thrombosed portal vein. Post recanalization of the portal vein, a snare is placed within it, which can be used as a target from the transjugular side for access. This guidewire inserted from the jugular route is snared from the percutaneous mesenteric vein entry site to establish Archimedean access. The procedure is thereafter completed via the jugular route using the standard technique.

Large, relatively less tortuous periportal collateral veins communicating with the superior mesenteric vein or splenic vein inferiorly can sometimes be used to create TIPS in patients who had a failure of TIPS via other approaches. These collaterals and the possible route through which they can be accessed via any of the three hepatic veins can be evaluated by preprocedural imaging (Figure 7 and Figure 8).

However, accessing a suitable collateral vein is often difficult and risks extrahepatic portal vein laceration and hemoperitoneum. An infographic summary of chronic PVT and its pertinent clinical and therapeutic features is shown in Figure 9.