Introduction We aimed to investigate the use of ICG videoangiography with FLOW800 hemodynamic parameters intraoperatively during STA-MCA bypass surgery to predict patency prior to anastomosis. In turn, this may allow surgeons to choose the ideal recipient and anastomosis site.

Methods A retrospective and exploratory data analysis of 32 patients was conducted using FLOW800 software to assess 4 regions of interest (proximal/distal recipient and adjacent/remote gyrus) for 4 hemodynamic parameters: speed, delay, rise time, and time to peak. Medical records were used to classify patients into flow and no-flow groups based on immediate anastomosis patency. Hemodynamic parameters were compared between the two groups via univariate and multivariate analysis. In addition, Principal Component Analysis (PCA) was used to identify ‘high-risk’ and ‘low-risk’ groups for no-flow and to assess hemodynamic parameters in relation to long-term patency.

Results 30 patients demonstrated immediate flow after anastomosis revascularization and were compared to 2 patients with no-flow post-revascularization. Proximal recipient speed and distal recipient speed were significantly different between no flow patients and flow patients (p<0.001, p<0.05, respectively). Based on the PCA, 6 patients were identified for each ’high-risk’ and ’low-risk’ groups for no-flow. The ‘high-risk’ group for no-flow (n=6) was characterized by high flow speed (>75th percentile) in all ROIs, reduced adjacent gyrus delay and short distal/remote rise time (<25th percentile each), whereas ‘low-risk’ group (n=6) were characterized by directly opposite parameter patterns. Long-term flow assessment demonstrated reduced flow in ‘high-risk’ patients (5/6), whereas ‘low-risk’ patients maintained robust patency (3/4; 2 remained without follow-up).

Conclusion Our results suggest that high recipient speed measured intraoperatively elevates the risk of no-flow and long-term reduced flow, potentially due to reduced local demand. With increased dataset size, continued FLOW800-based ROI metric analysis could be used to guide intra-operative anastomosis site selection prior to anastomosis and predict patency outcome.

Disclosures K. Sangwon: None. A. Liu: None. C. Rabbin-Birnbaum: None. D. Wiggan: None. D. Alber: None. E. Nossek: None.