Background An association between increased number of device passes and poor functional outcome of patients undergoing mechanical thrombectomy (MT) within 24 hours has been described. Potential benefit of MT beyond the standard 24-hour window for select patients has been proposed, but not well studied. Our goal was to investigate if the number of device passes affect MT outcomes in this unique cohort.

Methods We conducted a retrospective analysis of a prospectively maintained database of patients who underwent MT beyond the conventional 24-hours of symptoms onset. Age, sex, ΔNIHSS (baseline – discharge), number of device passes, procedure time, complications, final TICI score, symptomatic intracerebral hemorrhage (sICH), and modified Rankin Scale (mRS) were collected. Primary outcome was good functional status at 90 days (mRS 0-2), reported as odds ratio (OR) with 95% confidence interval (CI).

Results A total of 39 patients (1 pass= 15, 2 passes=11, and 3 passes=13) was included. The median (interquartile range – IQR) age was 69 (61.5-73.5) years and 54% were females. Baseline NIHSS was 11 (7.0-19.5). The median (IQR) procedure time was 77 (49.5-111.5) minutes. Median (IQR) number of passes was 2 (1.0-3.0). Procedure time was shortest for the 1 pass group at 47 minutes, followed by 91 minutes with 2 passes, and 122 minutes with 3 passes. Successful recanalization (TICI 2b-3) was achieved in 87%, 91%, and 85% of patients after 1 vs. 2 vs. 3 passes, respectively. Good functional status was achieved in 33%, 45%, and 69%, respectively. The number of passes was not associated with functional outcome (OR 0.57, [0.29-1.04]; p=0.08). ΔNIHSS among these 3 groups was not significantly different. A total of 3 patients (8%) developed sICH. All patients who developed sICH had 2 device passes.

Conclusion In our patients undergoing MT beyond the 24-hour window, the number of device passes was not associated with functional outcome, successful recanalization, or sICH. This may be due to the delayed intervention window, small sample size, or other factors. A larger study and further investigation is warranted.

Disclosures A. Pandhi: None. A. Alrohimi: None. M. Abdulrazzak: None. M. Bain: None. N. Moore: None. M. Hussain: None. D. Wadden: None. J. Bullen: None. G. Toth: None.