Comparison of safety and technical parameters between transhepatic (TH-PVE) and transsplenic (TS-PVE) portal vein embolization for future liver remnant (FLR) augmentation before hepatectomy: A randomized controlled trial.

Major hepatic resections are often required for the curative treatment of hepatic and biliary malignancies such as hepatocellular carcinoma, cholangiocarcinoma, Gallbladder carcinoma and colorectal or neuroendocrine hepatic metastases.In patients with insufficient future liver remnant (FLR), preoperative portal vein embolization (PVE) is a well-established technique to enhance FLR hypertrophy by redirecting portal flow, thereby reducing the risk of postoperative liver failure.

Glue (N-butyl cyanoacrylate) is the embolic material of choice owing to its instant PV obliteration and superior FLR hypertrophy. Traditionally, transhepatic route is preferred for PVE, either through an ipsilateral or contralateral approach. Despite technical ease, ipsilateral approach is increasingly preferred than contralateral approach for right hepatectomy to avoid the risk of FLR damage. However, ipsilateral transhepatic route possesses several disadvantages. Firstly, ipsilateral approach is associated with difficult cannulation of PV branches due to sharp angulation and may require different shaped catheters, including SIM1 catheter which in turn increases the procedure time and radiation exposure. Second, inadvertent proximal glue embolization may pose difficulty in hooking of different PV branches during the process of embolization. Further, at least 1 cm stump of right PV free of embolization is required for PV ligation during hepatectomy. However, glue is difficult to control and the operator may find difficulty in controlling glue flow while embolizing. Sometimes, non-target embolization into the FLR has also been noticed, especially in the process of final flush venography. There is a possibility of glue spillage into the perihepatic space during tract embolization. This spilled glue may cause perihepatic adhesion, creating technical difficulty during hepatic resection.  Lastly, transhepatic approach carries a risk of unintentional biliary puncture, increasing the risk of cholangitis, cholangitic abscess and biloma formation .

With the evolution of techniques, hardwires and availability of USG, trans splenic access is gaining popularity for various portal-hypertension related interventions. Recent studies have shown no significant increase in bleeding risk with trans splenic access as compared to transhepatic access.  In a subset of patients, trans  splenic access may be a viable alternative to transhepatic PVE, especially when extensive tumoral infiltration precludes a transhepatic PV access. Antegrade access to PV via trans splenic route could have advantages of straight forward catheterization of right portal vein branches and superior glue control with easy embolization of individual PV branches. It eliminates the risk of dislodgement of embolic agent during final venogram. Trans splenic access will also preclude the risk of perihepatic adhesion resulting from glue spillage.

Despite the growing use of the trans splenic approach, there is limited evidence directly comparing it to the transhepatic route in PVE in terms of safety and difference in technical parameters as well as challenges faced during hepatic resection.

The study will be conducted as prospective randomized control trial in department of Radiodiagnosis in AIIMS Bhubaneswar. This study aims to evaluate and compare the safety and technical parameters between transhepatic and trans splenic PVE in a prospective manner, providing evidence to guide route selection and optimize outcomes in patients undergoing major liver resection.