Efficacy and safety of virtual-assisted lung mapping using dual staining with indigo carmine and indocyanine green in sublobar lung resection: a single-arm prospective cohort study

Background: Virtual-assisted lung mapping (VAL-MAP) using indigo carmine is widely used to localize small pulmonary nodules during sublobar lung resection. However, the visibility of markings remains suboptimal. We developed a novel dual-staining technique (VAL-MAP DS) that combines indigo carmine and indocyanine green (ICG) to enhance marking visibility. This study aimed to prospectively evaluate the efficacy and safety of VAL-MAP DS. Methods: This single-arm prospective cohort study included patients who underwent sublobar resection of pulmonary nodules at a single tertiary center. Preoperative VAL-MAP DS was performed using bronchoscopic dye injection with both indigo carmine and ICG. The primary endpoint was the success rate of marking detection, defined as intraoperative visibility of either indigo carmine or ICG. Secondary endpoints included the successful resection rate, bronchoscopy-related adverse events, and postoperative complications. Results: A total of 158 markings were performed for 51 nodules in 48 patients. The overall marking success rate was 98.1% [155/158; 95% confidence interval (CI): 94.6-99.6%] and significantly exceeded the threshold of 90% based on historical data of conventional VAL-MAP using indigo carmine alone. The successful resection rate was 94.1% (48/51; 95% CI: 83.8-98.8%). Bronchoscopy-related adverse events and postoperative complications occurred in 4.2% and 6.3%, respectively. Conclusions: VAL-MAP DS may enhance intraoperative marking visibility with minimal procedural risk. This dual-staining approach enables more accurate sublobar resections and may reduce the number of markings required per lesion.