Abstract W P8: Role of Core Infarct Volume Affecting the Number Needed to Treat in Endovascular Therapy for Acute Ischemic Stroke From Large Vessel Occlusion
Purpose: The infarct core has been hypothesized to be highly predictive of treatment effect for endovascular intervention in acute ischemic stroke from large vessel proximal occlusion. The purpose of this study was to determine how it affects the number of patients needed to treat (NNT) by this therapy to improve long term functional status.
Methods: Patients with acute stroke not eligible and/or refractory to IV rtPA, treated by the Penumbra System (N=463) were pooled from various studies: Pivotal (N=83), PICS (N=174), RetroSTART (N=96) and START (N=110). They were compared with 62 control patients who were eligible for but not treated by endovascular therapy. The NNT for both groups to achieve 90 day functional independence as defined by an mRS score of ≤2 were compared. The impact of the infarct core at presentation defined by ASPECTS trichotomized as small (8-10), medium (5-7) and large (0-4) was assessed. The distribution of the infarct core (N) for Penumbra:control patients were: 257:50, 155:7 and 51:3, respectively for small, medium and large. Two control patients did not have ASPECTS scores.
Results: There were no differences in baseline characteristics between the two group median values (Control;Penumbra): Age (72;68), NIHSS (18;17), ASPECTS (ASP) (9;8). There were significant differences in rate of recanalization, all-cause mortality and good functional outcome (mRS ≤2) but not symptomatic ICH (Table). The NNT to improve functional status was 5.6 for the entire cohort of treated patients, 4.7 for those with small core, 4.1 for medium and 12.8 for large.
Conclusion: These data indicate that endovascular treatment may not be effective in patients with a large infarct core and could contribute to the high NNT needed to achieve long term good functional status. Eliminating this group at time of triage may significantly lower the NNT and improve the treatment effect of this therapy.
Author Disclosures: O.O. Zaidat: Honoraria; Modest; Penumbra, Inc. A. Yoo: Research Grant; Significant; Penumbra, Inc.. V. Janardhan: None. D. Frei: Speakers' Bureau; Modest; Penumbra, Inc. L. Ammar: Employment; Significant; Penumbra, Inc. D. Myer: Employment; Significant; Penumbra, Inc. C. To: Employment; Significant; Penumbra, Inc. S.S. Kuo: Employment; Significant; Penumbra, Inc. H. Buell: Employment; Significant; Penumbra, Inc. L. Barraza: Employment; Significant; Penumbra, Inc. A. Bose: Employment; Significant; Penumbra, Inc.. Ownership Interest; Significant; Penumbra, Inc. S. Sit: Employment; Significant; Penumbra, Inc.. Ownership Interest; Significant; Penumbra, Inc..
- © 2014 by American Heart Association, Inc.