Feasibility And Safety Of Transjugular Intrahepatic Portosystemic Shunt (TIPS) Creation Using A Radiofrequency Guidewire

The transjugular intrahepatic portosystemic shunt procedure (TIPS), first described in 1969 by Rösch et al., has been widely used to treat the complications of portal hypertension such as recurrent variceal hemorrhage and refractory ascites.

In the TIPS procedure, an intrahepatic connection between a hepatic vein and a portal vein branch is created in order to reduce the portal venous pressure. A dedicated device developed for the TIPS procedure, the Rösch-Uchida Transjugular Liver Access Set (RUPS), is widely used for this procedure. The most challenging and time-consuming part of TIPS creation is puncturing the portal vein from the hepatic vein with a long needle trocar. Occasionally in cirrhotic livers, the trocar needle can deflect and not easily pass through the parenchyma. Needle deflection may lead to additional needle passes and potentially increase risk of inadvertent injury to the liver or extracapsular puncture. There is need, therefore, for a device that can easily penetrate dense liver tissue without creating significant trauma.

A novel radiofrequency (RF) wire created by Baylis Medical (Montreal, CAN) is an FDA cleared device commonly used for percutaneous recanalization procedures. This wire has an active tip that delivers focused RF energy and has been applied for many procedures such as percutaneous transseptal left heart access, recanalization of central vein occlusion, recanalization of arterial occlusion, and recanalization of bile duct occlusion.

The investigators have assessed the application of the RF wire for TIPS creation in a swine model. The investigators found that the use of this wire to cut through tissue during TIPS creation is feasible in swine with some potential advantages compared with the current available tools. The RF wire device was well visualized under intravascular ultrasound (IVUS) guidance and could penetrate through the liver parenchyma smoothly and safely. In addition, the RF wire was able to subsequently be used as a working wire to complete the procedure. Advantages in clinical practice with cirrhotic livers would be the relative ease of penetration into a hardened liver compared to the trocar needle, and the additional benefit of being able to use the device as a working wire to minimize the risk of catheter displacement and decrease procedure time.

There has been no study investigating the use of the RF wire for TIPS creation in clinical practice with humans. Having the promising results of the experimental investigation in swine, the investigators are seeking to assess the feasibility and safety of the RF wire to cut through tissue in the liver while creating TIPS in the clinical setting. It is anticipated that the proposed experimental technique using the RF wire would be at least as safe as the current standard technique. The wire diameter, 0.035 inches, is smaller than the traditionally used 0.038 inch needle trocar, and the deposition of RF energy is limited to the wire tip with minimal collateral damage. Risks of complications, such as puncturing unintended structures including the liver capsule, hepatic artery, gallbladder and biliary tree are anticipated to be at least as low as for the standard technique, estimated at about 3-4%. Moreover, these risks may be reduced even further in the experimental technique owing to the use of intravascular ultrasound guidance, enabling direct visualization of the puncture compared to the standard technique using landmarks and reference images under x-ray fluoroscopy.