Abstract 3785: Distal Occlusions And Smaller Clots Show High Early Recanalization Rates With iv tPA: Pilot Data From The Multi-center Interrsect Study.

Introduction: We seek to present results from INTERRSeCT, an ongoing prospective multicenter imaging based cohort study aimed at understanding thrombus characteristics on CT that predict early recanalization with intravenous thrombolysis. Methods: The pilot data analysed includes any patient (age ≥ 40) presenting to the emergency department with symptoms consistent with ischemic stroke and with evidence of a visible and symptomatic intracranial occlusion on baseline CT-angio. Each patient enrolled in the study had early recanalization assessed on repeat CT-angio within 3-5 hours of baseline imaging or on conventional angio at end of intervention. Imaging data including various thrombus characteristics were analyzed in a core-imaging lab at the University of Calgary. Results: Of 101 patients included in INTERRSeCT, 63 patients received IV t-PA at baseline. Of these, 40 patients (mean age 71+/- 12.5 yrs, 52% male) treated with IV t-PA alone have been included for this analysis. The median stroke symptom onset to CT time was 134.5 minutes (IQR 77 mins) and median IV t-PA to repeat CTA time was 228 minutes (IQR 82 mins). Overall recanalization rate in this cohort was 24/40 (60%). Recanalization rates by site of occlusion were as follows: ICA - 2/8 (25%), M1 MCA - 4/10 (40%), M2 MCA - 11/15 (73.3%), M3 MCA (n=2), PCA(n=2) and ACA(n=3) - 7/7 (100%) (p=0.01). Median clot lengths by site of occlusion were as follows: ICA (5 cm), M1 MCA (2.44 cm), M2 MCA (1.81 cm), M3 MCA, PCA and ACA combined (0.8 cm). Median clot length at baseline CTA was significantly lower in the recanalizers when compared to the non-recanalizers. (1.64 cm vs 2.68 cm, p = 0.01). ( Table ) Conclusion: M2 MCA and other distal occlusions show high early recanalization rates with IV t-PA. These high recanalization rates could be due to smaller clot length.