Quality Improvement for Portal Vein Embolization

Abstract

Future liver remnant (FLR) is the liver that will be left in place after surgery and that was not targeted by embolization. The FLR must hypertrophy after portal vein embolization (PVE). Most teams wait 4 weeks before surgery. FLR hypertrophy must be measured by way of computed axial tomography (CAT) examination after injection of iodine with volumetric measurements of the FLR segments, with the results compared with the measurements performed before PVE using the same technique. Hypertrophy can be quantified as FLR hypertrophy, which is defined as the difference between FLR after a waiting period from 3 to 6 weeks after PVE minus FLR before PVE divided by FLR before PVE. The waiting period must be long enough to allow hypertrophy and as short as possible to avoid tumor growth, which precludes surgery. Hypertrophy can also be quantified by increased FLR ratio. The FLR ratio is defined as (FLR volume—tumor in the FLR)/(total liver volume—total tumor volume) [8]. Technical success of PVE is defined by a complete occlusion of portal branches feeding the future resected liver segments. Branches of the FLR must be patent with hepatopetal flow. In the late phase of control portography, parenchymography must be visible only in the FLR. Clinical success is considered to occur when the patient reaches the volumetric criteria for liver resection. Major hepatic resection (or major hepatectomy) is defined as a resection of at least four of eight segments of the liver. Right hepatectomy is defined as a resection of segments V to VIII. Extended right hepatectomy additionally includes segment IV. Resection rate is defined as the number of embolized patients that will ultimately be resected.