The measured hepatic function increase after portal vein embolization measured by 99mTc-mebrofenin hepatobiliary scintigraphy is not attributed by an increased microvascular blood flow

Abstract

Introduction: Patients scheduled for major liver resection and found unresectable due to insufficient FRL function and volume can undergo portal vein embolization (PVE) to increase resectability. Hereby inducing hypertrophy in the non-embolized lobe with concomitant atrophy in the embolized lobe. The functional gain of the FRL can be assessed with hepatobiliary scintigraphy (HBS). The aim of this study is to determine whether the measured increase in FRL function is the result of an increased hepatic microvascular flow, rather than solely an increase in functional mass by assessing the microcirculatory parameters of both lobes. Methods: Eight patients were included. FRL function was assessed with HBS before and after PVE. During resection, the hepatic microcirculation was assessed with intravital handheld microscope (Cytocam) in both the embolized and non-embolized lobe. Microvascular density parameters (respectively total vascular density (TVD) and perfused vessel density (PVD)) and flow parameters (respectively proportion of perfused vessels (PPV) and red blood cell velocity (RBCv)) were measured. Results: Three weeks after PVE, there was a significant increase function of the non-embolized lobe (P < 0.01). Subsequently, for the microvascular parameters, the non-embolized lobe showed a significantly higher microvascular density (TVD, P < 0.001 and PVD, P < 0.001), without differences in the microvascular flow (PPV, P = 0.43 and RBCv, P = 0.32). Conclusion: This increase in measured hepatic function with HBS after PVE is not attributed by an increase in hepatic microvascular blood flow. This indicates that the measured hepatic function after PVE reflects the increase in hepatic function.