Abstract TP127: Pretreatment CT Collateral Parameters Predict Good Outcomes in Successfully Recanalized Middle Cerebral Artery Distal Medium Vessel Occlusions

Abstract

Background/Purpose: Distal medium vessel occlusions (DMVOs) account for a large percentage of vessel occlusions resulting in acute ischemic stroke (AIS) with disabling symptoms. We aim to assess whether pretreatment CTP collateral status (CS) parameters can serve as imaging biomarkers for good clinical outcomes prediction in successfully recanalized middle cerebral artery (MCA) DMVOs. Methods: We performed a retrospective analysis of consecutive patients with AIS secondary to primary MCA-DMVOs who were successfully recanalized by mechanical thrombectomy (MT) defined as modified thrombolysis in cerebral infarction (mTICI) 2b, 2c, or 3. We evaluated the association between CBV index and HIR independently with good clinical outcomes (modified Rankin score 0-2) using Spearman rank correlation, logistic regression, and ROC analyses. Results: From 8/22/2018 to 10/18/2022, 60 consecutive patients met our inclusion criteria (mean age 71.2 +- 13.9 years old [mean+-SD], 35 female). CBV index (r = -0.693, p < 0.001) and HIR (0.687, p < 0.001) strongly correlated with 90 day mRS. A CBV index >= 0.7 ((OR 2.27 [6.94 - 21.23], p = 0.001)) and lower likelihood of prior stroke (0.13 [0.33 - 0.86]), p = 0.024) were independently associated with good outcomes.ROC analysis demonstrated good performance of CBV Index in predicting good 90 day mRS (AUC 0.73, p = 0.003) with a threshold of 0.7 for optimal sensitivity (71% [52.0-85.8%]) and specificity (76% [54.9 - 90.6%]). HIR also demonstrated strong performance in predicting good 90 day mRS (AUC 0.77, p = 0.001) with a threshold of 0.3 for optimal sensitivity (64.5% [45.4-80.8%]) and specificity (76.0% [54.9 - 90.6%]). Conclusion: A CBV index ≥ 0.7 may be independently associated with good clinical outcomes in our cohort of AIS caused by MCA-DMVOs that were successfully treated with MT. An HIR < 0.3 is also associated with good clinical outcomes. This is the first study of which we are aware to identify a CBV index threshold for MCA-DMVOs.