384 Intraoperative Venous Outflow Assessments During Obliteration of Dural Arteriovenous Fistula Using Hemodynamic Changes of FLOW800 Technology

INTRODUCTION: Dural Arteriovenous Fistula (dAVF) surgery is a microsurgical procedure that requires confirmation of obliteration using formal cerebral angiography. However, the lack of intraoperative angiogram or the need for post operative angiogram in some settings necessitates a search for alternative, less invasive methods to verify surgical success. Beyond the qualitative confirmations ICG can provide, we aimed to assess quantitative results as an additional confirmation using FLOW800. This study explores the potential of FLOW800 technology to detect hemodynamic changes associated with dAVF obliteration, proposing its utility as an indirect indicator of successful surgery. METHODS: We conducted a retrospective analysis of eight patients who had successful spinal or cranial dAVF obliteration confirmed with intraoperative angiogram. FLOW800 was used to intraoperatively measure four hemodynamic parameters (Delay Time, Speed, Time to Peak, Rise Time) across fistulization venous drainage regions of interest (ROIs) before and after obliteration totaling 16 each. Statistical analysis included non-parametric Mann-Whitney U tests, with visualizations via box plots, violin plots, Principal Component Analysis (PCA), and finally Cumulative-Distribution-Functions to evaluate statistical shifts in distributions and clustering patterns. RESULTS: All four features demonstrated changes in data distribution pre/post-dAVF obliteration in the venous ROIs. Post-resection changes showed a significant increase in Delay Time (median:2.40vs.7.85s, p=0.020) and decrease in Speed (median:13.5vs.5.5s, p=0.029). PCA exhibited distinct clustering of pre- and post-obliteration hemodynamics with several overlapping datapoints. CDF curve demonstrated right shifts (increase) in delay time, time-to-peak, and rise-time, and left shift (decrease) in speed post-dAVF obliteration. CONCLUSIONS: Our findings suggest that FLOW800 can effectively quantify and visualize the immediate hemodynamic shifts consistent with expected physiological changes following dAVF obliteration, offering an additional potential non-invasive method to intraoperatively confirm the success of the surgery.