Advanced Techniques

TIPS have been successfully created through occluded hepatic veins, thrombosed portal veins, and tumor-occluded portal veins. Techniques for accessing difficult portal anatomy have included shunt into left, middle, or caudate portal veins, portal access via transhepatic or transsplenic punctures, minilaparotomy allowing portal access via jejunal veins, and portal access through enlarged umbilical veins (9). Techniques to avoid difficult hepatic venous anatomy include use of the left and middle hepatic veins,

Fig. 3. Wedged hepatic venous portagram.

shunt directly to the intrahepatic IVC, stent of stenotic or occluded hepatic veins, and transhepatic access to intrahepatic branches of the hepatic vein. Techniques to overcome absence of the right internal jugular vein include access from the right external jugular vein, left internal jugular vein, and right common femoral vein, as well as transhepatic punctures (9).

It is fair to say that the only limitations are in the imagination and experience of the interventionalist seeing the patient, and that no patient needing a shunt should be excluded a priori for reasons of anatomy. Rather, patients presenting with anatomic challenges should be counseled regarding lower chance of technical success, and should be sent to an interventional radiologist who is very experienced in the procedure. Overshunted patients can be salvaged by the creation of a reducing stent, which is placed into the TIPS to reduce, but not occlude its flow. Varices showing high-grade hepatofugal flow after hemodynamically successful shunt creation can be catheterized via the TIPS and embolized with metallic coils. It is important to remeasure the portosystemic gradients after embolization because closing a high flow varix cuts off a high-flow exit from the portal system and can raise portal pressure (9).

Covered stents are a new and potentially revolutionary development. The available designs consist of conventional metallic stents covered with PTFE or other biocompatible material. The covering excludes the shunted blood from the surrounding hepatic envi-

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