Intraoperative assessment of reconstructed vessels in living-donor liver transplantation, using a novel fluorescence imaging technique

Abstract

In living-donor liver transplantation (LDLT), hepatic arterial thrombosis and portal venous thrombosis are critical problems that can result in graft loss. Only intraoperative Doppler ultrasound (IDUS) is able to evaluate blood flow in the reconstructed vessels. The aim of this study was to evaluate the utility of a newly developed fluorescence imaging technique using indocyanine green (ICG) for visualizing reconstructed vessels. In three patients who had undergone LDLT, IDUS was performed after reconstruction of the portal vein and hepatic artery. Fluorescence images were then recorded, using a SPY system (Novadeq Technologies), which employs ICG as a fluorescent imaging medium activated by light. The ICG (3.75 mg) was injected intravenously, then, 10 s later, the images were recorded for 30 s (first photographic recording). Two minutes later, the same procedure was repeated (second photographic recording), and 40 min later, images were obtained without injection of ICG (third photographic recording). After portal venous reconstruction, IDUS demonstrated a nonphasic and continuous waveform, with a mean velocity of 52.1 cm/s and a mean portal blood flow volume of 69.5 ml/s per kg. After hepatic arterial reconstruction, a pulsatile waveform with a mean peak systolic velocity of 52.4 cm/s and a mean resistance index of 0.76 was obtained. The first photographic recording clearly visualized the blood flow in the reconstructed hepatic artery, without kinking or stenosis, in all three patients. The second photographic recording visualized the flow in the portal vein without stenosis, kinking, or stagnation. The third photographic recording demonstrated the excretion of ICG into bile, thus confirming bile production by the grafts. Fluorescence imaging can clearly visualize the reconstructed hepatic artery and portal vein and demonstrate the production of bile by a transplanted liver graft. A combination of IDUS and the new system can guarantee the patency of the reconstructed vessels.