Real-time fluorescent cholangiography with indocyanine green in laparoscopic cholecystectomy: a randomized controlled trial to establish the optimal indocyanine green dose within 30 min preoperatively

Purpose: To establish the optimal dose of indocyanine green (ICG) to administer intravenously 30 min before laparoscopic cholecystectomy (LC).

Methods: In this randomized controlled trial (RCT), patients undergoing LC for cholecystitis, cholelithiasis, and/or cholecystic polyps were randomized into four groups given four different ICG doses (0.025, 0.1, 0.25, 2.5 mg). Using OptoMedic endoscopy combined with a near-infrared fluorescent imaging system, we evaluated the fluorescence intensity (FI) of the common bile duct and liver at three timepoints: before surgical dissection of the cystohepatic triangle, before clipping of the cystic duct, and before closure. The bile duct-to-liver ratio (BLR) of the FI was analyzed to assess the cholangiography effect.

Results: Sixty-four patients were allocated to one of four groups, with 40 patients included in the final analysis. Generally, with increasing ICG doses, the levels of FI in the bile duct and liver increased gradually at each of the three timepoints. Before surgical dissection of the cystohepatic triangle, 0.1-mg ICG showed the highest BLR (F = 3.47, p = 0.0259). Before clipping the cystic duct and before closure, the 0.025- and 0.1-mg groups showed a higher BLR than the 0.25- and 2.5-mg groups (p < 0.05). When setting the ideal cholangiography at a BLR ≥ 1, ≥ 3, or ≥ 5, the 0.1-mg group showed the highest qualified case number at the three timepoints.

Conclusions: The intravenous administration of 0.1-mg ICG, 30 min before LC, is significantly better for fluorescent cholangiography of the extrahepatic biliary structures before dissection and clipping of the cystohepatic triangle.

Trial registration: This study was registered in the Chinese Clinical Trial Registry (ChiCTR) (ChiCTR2200057933).