Indocyanine green plasma clearance rate and 99mTc-galactosyl human serum albumin single-photon emission computed tomography evaluated preoperative remnant liver

BACKGROUND: Preoperative evaluation of future remnant liver reserves is important for safe hepatectomy. If the remnant is small, preoperative portal vein embolization (PVE) is useful. Liver volume analysis has been the primary method of preoperative evaluation, although functional examination may be more accurate. We have used the functional evaluation liver using the indocyanine green plasma clearance rate (KICG) and 99mTc-galactosyl human serum albumin single-photon emission computed tomography (99mTc-GSA SPECT) for safe hepatectomy. AIM: To analyze the safety of our institution’s system for evaluating the remnant liver reserve. METHODS: We retrospectively reviewed the records of 23 patients who underwent preoperative PVE. Two types of remnant liver KICG were defined as follows: Anatomical volume remnant KICG (a-rem-KICG), determined as the remnant liver anatomical volume rate × KICG; and functional volume remnant KICG (f-rem-KICG), determined as the remnant liver functional volume rate based on 99mTc-GSA SPECT × KICG. If either of the remnant liver KICGs were > 0.05, a hepatectomy was performed. Perioperative factors were analyzed. We defined the marginal group as patients with a-rem-KICG of < 0.05 and a f-rem-KICG of > 0.05 and compared the postoperative outcomes between the marginal and not marginal (both a-rem-KICG and f-rem-KICG > 0.05) groups. RESULTS: All 23 patients underwent planned hepatectomies. Right hepatectomy, right trisectionectomy and left trisectionectomy were in 16, 6 and 1 cases, respectively. The mean of blood loss and operative time were 576 mL and 474 min, respectively. The increased amount of f-rem-KICG was significantly larger than that of a-rem-KICG after PVE (0.034 vs 0.012, P = 0.0273). The not marginal and marginal groups had 17 (73.9%) and 6 (26.1%) patients, respectively. The complications of Clavian-Dindo classification grade II or higher and post-hepatectomy liver failure were observed in six (26.1%) and one (grade A, 4.3%) patient, respectively. The 90-d mortality was zero. The marginal group had no significant difference in postoperative outcomes (prothrombin time/international normalised ratio, total bilirubin, complication, post-hepatectomy liver failure, hospital stay, 90-d, and mortality) compared with the not-marginal group. CONCLUSION: Functional evaluation of the remnant liver enabled safe hepatectomy and may extend the indication for hepatectomy after PVE treatment.