Abstract 53: Multimodal CT Imaging: Time to Treatment and Outcomes in the Interventional Management of Stroke (IMS) III Trial

Introduction: The importance of time in acute stroke is well established. Using the Interventional Management of Stroke (IMS) III trial data, we explored the effect of imaging on time to treatment and outcomes for subjects those receiving multimodal imaging [CT angiogram (CTA) + CT perfusion (CTP) versus CTA alone] versus those who did not. Materials and Methods: Multimodal CT was not a prerequisite for IMS III entry .We examined 3 subgroups; those with baseline CTA alone, CTA + CTP, versus those with no CTA or CTP. The baseline demographics and imaging and treatment time parameters of these 3 subgroups were studied. Results: Of the 656 subjects enrolled, 98 (14.9%) underwent baseline (pre-IV t-PA treatment) CTA+CTP. 8 out of these 98 patients received only CTP. 216 (32.9%) received CTA alone and 342 (52.1%) had neither. Time parameters for the CTA+CTP, CTA alone, and no CTA/CTP groups were as follows: median from stroke onset to IV t-PA (120.5 vs. 117.5 vs 120 min; p=0.5869), median IV t-PA bolus to groin puncture (GP) (78 vs. 81 vs. 91 min; p=0.0043) and median GP to start of endovascular therapy (EVT) (31 vs. 38 vs. 44 min; p=0.0001). Pairwise comparison demonstrated no significant difference in time from IV tPA to GP and time from GP to IA therapy between CTA+CTP and CTA alone groups (p=0. 9883 and p=0.1421, respectively). With removal of drip n’ ship subjects, no statistical differences were seen between groups for time from onset to IV t-PA bolus (p=0.5509) or time from imaging to GP (p=0.8459). Time from GP to start of EVT was still shorter in the CTA+CTP and CTA alone paradigms (p =0.0019). In the IV t-PA treatment arm, no differences in 90d mRS 0-2 outcome were seen in the 3 subgroups (36.4% versus 40.9% versus 38.2%; p=0.8941). In the EVT arm, differences in good outcome were seen (38.5% versus 52.0% versus 33.8%; p=0.0020). CTA alone remained strongly associated with good outcomes in EVT arm (adjusted OR, 2.117; 95% CI, 1.35- 3.30), irrespective of age, stroke severity and time from onset to IV tPA initiation. Conclusion: Multimodal imaging did not delay treatment times in IMS III. The CTA alone group was associated with favorable clinical outcomes in the endovascular arm. The CTA+CTP paradigm resulted in worse outcome over the CTA alone paradigm in the endovascular arm.