Abstract WP52: A Novel CT-angiogram Based Recanalization Grading System (TICI-CTA) Correlates With Early Neurologic Response After Intravenous tPA Therapy

Abstract

Introduction: Noninvasive imaging tools to assess the degree of recanalization are limited. CT-angiography (CTA) may be ideal for assessment of recanalization in view of excellent visualization of thrombus and distal vasculature; however no scoring system is available to evaluate extent of recanalization. We sought to derive a score and test it’s correlation to early neurologic response (24 hours NIHSS) within a research study having a post tPA CTA. Method: The TICI-CTA score was defined by debulking of thrombus of proximal intracranial arterial occlusive lesion (PIAOL) and forward filling of distal arterial tree.(see graphic) Data is from INTERRSeCT, an ongoing multi-center study evaluating thrombus characteristics and recanalization in acute stroke. Results: From 166, 78 patients treated with IV tPA were evaluated. The cohort had 48% males. The median time from symptom onset to baseline CTA was 114 min, and onset to IV tPA bolus was 148 min. Proximal intracranial sites of occlusions were: carotid-T 6.4%, M1-MCA 26.9%, distal MCA 58.9%, PCA 6.4%, and vertebral 1.3%. The symptom onset to follow-up post treatment CTA was 373 min. The recanalization grading TICI-CTA in post iv tPA CTA was: TICI-CTA 0 in 30 (38.4%), TICI-CTA 1A/1B in 3 (3.8%); TICI-CTA 2A/2B/2C in 17 (21.7%); and TICI-CTA 3 in 28 (35.8%). We noted a significant positive correlation between TICI-CTA score and absolute change in NIHSS from baseline to 24 hours (r=0.26, p=0.02). A positive correlation was also noted between TICI-CTA score and proportional change in NIHSS from baseline to 24 hrs (r=0.34, p<0.01). Conclusion: The TICI-CTA score based on comparison of pre and post treatment CTA correlates with early neurologic response, thus showing content validity. Further validation is needed. This grading score could be used to evaluate the recanalization efficacy of novel lytics and combination therapies in phase 2 proof of concept or as a predefined CTA sub-study in a pivotal Phase 3 clinical trial.