Blood-brain Barrier Profile Influences Outcome After Mechanical Thrombectomy In The Frame Study.

Background and Purpose: The FRAME study demonstrated that even in the early time window (<6hrs) perfusion imaging profiles can influence response to mechanical thrombectomy. Perfusion imaging (PWI) can also be used to measure damage to the blood-brain barrier (BBB) which has been shown to be associated with increased risk of hemorrhagic complications (HC) with treatment. We aimed to determine if BBB profiles in the FRAME study would influence outcome after mechanical thrombectomy (MT). Methods: This was a post-hoc analysis of the FRAME study which enrolled stroke patients with large vessel occlusion who received MT within 6 hours of stroke onset. Patients with successful pre-treatment MRI PWI were included. We tested the hypothesis that more severe pre-treatment BBB disruption is associated with higher frequency of HC after MT. BBB disruption was measured as the percent of signal change due to gadolinium leakage on the PWI source images. Mean permeability derangement (MPD) was defined as the average of all voxels in the stroke core that are two standard deviations above normal. The outcome of HC was defined as any type of parenchymal hematoma (PH1 or PH2); poor functional outcome was defined as mRS >2 at 90 days. MPD was compared with HC and functional outcome using the Wilcoxon signed-rank test and logistic regression. A prespecified MPD threshold of 20% was tested as a predictor of HC based on prior studies. Results: There were 164 patients included in the analysis, median age 74 and 48% female. HC occurred in 57 patients. The average MPD was 15.1% for patients with HC and 8.7% for patients without HC. Elevated MPD was significantly associated with HC (p<0.0001) with a 25% increased risk of HC for each 5% increase in MPD (OR 1.25; CI 1.09:1.45; p=0.0018). Increased MPD was also associated with poor functional outcome (p=0.0002). ROC analysis confirmed the prespecified MPD threshold, identifying 19.7% as the optimal cut point for classification. MPD greater than 20% more than tripled the risk of HC (OR 3.37; CI 1.49:7.85; p=0.004). Conclusions: Increased pre-treatment BBB disruption has a substantial influence on the risk of HC after MT. Integration of BBB imaging into patient selection algorithms to improve MT outcomes should be tested further.