Virtual-assisted lung mapping using dual staining with indocyanine green and indigo carmine enhanced marking detectability

BACKGROUND: Virtual-assisted lung mapping (VAL-MAP) is a preoperative bronchoscopic multispot dye-marking procedure to facilitate sublobar lung resection for unidentifiable lung nodules. To increase detectable markings, we performed VAL-MAP using dual staining (VAL-MAP DS) with indocyanine green (ICG) and indigo carmine. This study was designed to evaluate the efficacy and safety of the modified technique. METHODS: We retrospectively reviewed the records of patients who underwent VAL-MAP DS. Twenty patients with 27 lesions underwent 72 VAL-MAP DS markings. We investigated the overall detectable marking rate, visible marking rate, successful resection rate, and complications. RESULTS: The overall detectable marking rate, thanks to both ICG and indigo carmine, tended to be higher than the indigo carmine visible marking rate (95.7% vs. 85.5%, P=0.08). The successful resection rate with sufficient margins was 92.0%. There were no adverse events related to the use of ICG. ICG markings of the lungs of patients with a history of smoking more than 50 pack-years tended to be visible, but the staining was too extensive compared with the staining in patients who smoked less or not at all (58.8% vs. 0.0%, P<0.001). CONCLUSIONS: VAL-MAP DS is likely be efficacious and safe in enhancing the detectability of markings. This bronchoscopic technique should be considered as one of the optimal preoperative marking methods in thoracic surgery.