Abstract W MP22: Impact of Difference in Definitions of M1 and M2 segment of Middle Cerebral Artery on Acute Stroke Endovascular Therapy
BACKGROUND: The involvement of the different segment of middle cerebral artery has different implications in terms of acute stroke endovascular therapy as learnt from recent trials. It has been suggested in prior trials that M1 segment occlusion might benefit more from acute endovascular therapy as compared to M2 segment. Ongoing trials have different definitions for segments of middle cerebral artery.
METHODS: Retrospective review of latest 71 cases of either M1/M2 confirmed on Digital Subtraction Angiography (DSA) in prospectively maintained database of acute stroke interventions at our institute is performed. Of these, 49 cases have CTA performed prior to DSA (69%). Stroke Neurologist has blindly reviewed CTA angiogram. Conventional angiogram findings are considered accurate for the exact site of occlusion. Two definitions from REVASCAT trial and SWIFT PRIME trial are then scored based on CTA and assessed in respect to findings in DSA
RESULTS: As per RESVASCAT defintion, 34 out of 49 cases on CTA/MRA (69%) have M1 occlusion on CTA. Of these 34 cases, 32 are then found to have M1 occlusion on DSA as well. The number of M2 occlusions were 9 out of 49 (18%) on CTA and all of them were found to have M2 occlusion of DSA as well. The accuracy of RESVASCAT definition of M1 and M2 were 32/34 (94%) are 9/9 (100%) respectively.
As per SWIFT PRIME definition, 27 out of 49 cases (58%) on CTA/MRA have M1 occlusions on CTA. Of these 27 cases, all cases were found to have M1 occlusions on DSA as well. The number of M2 occlusions were 15 out of 49 (31%) on CTA and 9 were found to have M2 occlusions on DSA. The accuracy of SWIFT PRIME definition of M1 and M2 were 27/27 (100%) and 9/15(60%).
6 cases (12%) with M1 occlusions on CTA as per REVASCAT definition were defined as M2 occlusions as per SWIFT PRIME.
CONCLUSIONS: The examination of angiographic data found discrepancies between these two definitions. The accuracy of REVASCAT definition was better for M2 whereas the accuracy of SWIFT PRIME definition was better for M1. The different definition of middle cerebral artery segments could potentially lead to discrepancies in the eligibility criteria for acute endovascular interventions. The criteria used in determining the M1 and M2 segments should be consistent across the field.
Author Disclosures: D. Gulati: None. A. Ducruet: None. A. Aghaebrahim: None. B. Jankowitz: None. A. Jadhav: None. T. Jovin: None.
- © 2015 by American Heart Association, Inc.