Abstract WP197: Poor Venous Outflow is Associated With Ischemic Core Growth During Transfer in Acute Ischemic Stroke Patients With a Large Vessel Occlusion

Abstract

Introduction: Thrombectomy is an effective therapy for the treatment of acute ischemic stroke due to large vessel occlusion (AIS-LVO). Patients with small ischemic cores have the most favorable outcomes after thrombectomy, and core growth during the transfer from a primary to a comprehensive stroke center (PSC to CSC) can lead to worse outcomes. We determined if poor venous outflow (VO) prior to transfer to a CSC predicts ischemic core growth in AIS-LVO. Methods: AIS-LVO patients in the prospective CRISP2 study who had a CTA and CT perfusion (CTP) at a PSC and a follow-up CTP or MRI immediately after transfer to the CSC were screened for enrollment. VO was measured on CTA at the PSC using cortical venous opacification score (COVES). COVES 0-2 was defined as unfavorable VO (VO-) and 3-6 was defined as favorable (VO+). Ischemic core was determined on CTP at the PSC and DWI MRI or CTP at the CSC. The primary outcome was inter-hospital ischemic core growth rate defined as a ratio between core growth and time between scans. Results: 174 patients were included; 64% had VO+ and 36% had VO-. VO- patients had larger baseline ischemic core volumes (median 10.5 [IQR 0-23.3] vs 0 [IQR 0-11] ml, p=0.006) and worse CTA collaterals (TAN median 1.82 [IQR 0-3] vs 2.26 [IQR 1-3], p=0.0002). VO- experienced greater ischemic core growth (median 19.6 ml [IQR 2.5-38] vs 8.8 ml [IQR 1.5-21.7], p=0.005) and higher growth rate (median 5.7 ml/hr [IQR 1.4-13.4] vs 2.8 ml/hr [IQR 0.4-7.5], p=0.007) during transfer as described in Figure 1 . Conclusions: In AIS-LVO patients, VO- prior to transfer to a comprehensive stroke center correlated with increased ischemic core growth and more rapid core growth rates. These results have implications for neuroprotection trial design.