Abstract TMP90: Extension of Subarachnoid Hemorrhage Following Mechanical Thrombectomy is Associated With Clinical Outcomes: A Subgroup Analysis of CLEAR Trial

Abstract

Introduction: Subarachnoid hemorrhage (SAH) following mechanical thrombectomy (MT) is not uncommon. The prognostic implication for these patients remains unclear and may be affected by the extension of SAH. Methods: We included patients with SAH detected on CT after MT from CLEAR Study (The Vesalio NeVa Stent Retriever Study for Treatment of Large Vessel Occlusion Strokes). SAH was further classified according to extension degree into diffuse (> 1 extraparenchymal compartment) and non-diffuse. Unadjusted and adjusted logistic regressions were used to measure the association of both groups with modified Rankin Scale (mRS) (mRS) score at 90 days. Results: Among 139 patients, 20 SAH patients qualified for final analysis (10 with diffuse SAH: 10 with non-diffuse SAH). There were no statistically significant differences for sex, thrombolytics administration, pre mRS score, baseline NIHSS score, and procedure access (p >0.1) while there were statistically significant imbalances for age and site of occlusion (p=0.02). At the end of the procedure, there was no statistically significant difference in successful recanalization rates defined as a Modified Treatment in Cerebral Ischemia (mTICI) score of 2b or greater (100% in non-diffuse vs. 90% diffuse, P>0.99). However, non-diffuse SAH group were significantly associated with reduced disability at 90 days in both unadjusted (Common odds ratio [cOR] 11.09, 95% confidence interval [CI] (1.72-71.37), p = 0.01) and adjusted models (cOR 12.32, 95% CI 1.49-102.05, p = 0.02). Additionally, non-diffuse SAH group were significantly associated with significantly improved 90-day good functional outcomes defined as mRS 0-2 in unadjusted analysis (80% vs. 30%, OR 9.33, 95% CI 1.99-72.99, p = 0.03) but not in adjusted analysis (OR 7.84, 95% CI 0.55-109.94, p = 0.13). Median NIHSS at 24 hours was significantly lower in non-diffuse group compared to diffuse group (3 [2-6] vs. 17.5 [12-19], p< 0.001) while mortality was reduced to half but did not reach a statistical significance level (10% vs. 20%, p>0.99). Conclusions: Non-diffuse SAH was associated with better clinical outcomes compared to diffuse SAH. These findings may inform adjustable management approaches according to extension degree of SAH.