Abstract 321: Likelihood of complete reperfusion in patients requiring multiple passes is dependent on technique of first two attempts

Background Previous research shows that the chances of successful reperfusion during endovascular thrombectomy (EVT) decrease with each additional attempt. However, for patients who require multiple EVT passes, it remains unclear whether the specific techniques used in the first two attempts affect the likelihood of eventually achieving complete reperfusion. Methods All consecutive patients treated with EVT from 12 centers across the US were prospectively collected between 10/2018 ‐ 12/2021 (SVIN Registry). Patient were included if they underwent more than 2 passes. Patients were excluded for missing data. The primary outcome was likelihood of final TICI 2c/3 and was compared against three subgroups defined by the technique used for the first 2 passes: contact aspiration (CA), stent retriever (SR), or a combined technique (CT). This outcome was determined using multivariable logistic regression, adjusted for the use of balloon guide catheters, age, history of atrial fibrillation, coronary artery disease, hypertension, and diabetes. Results Among 857 patients that met inclusion criteria, median age was 70 years (IQR, 59‐90), 50.6% female and a median NIHSS 17 (IQR, 11‐21). 49.9% of patients achieved TICI 2c/3 in 2 or fewer passes (54.1% SR, 45.5% CA, 48.7% CT). Among patients who did not achieve TICI 2c/3 within the first two passes and in whom additional passes were attempted, final TICI 2c/3 was attained 32.1% with SR, 48.3% with CA, and 42.4% with CT. In multivariable logistic regression, CA for the first two passes was associated with 2.6 times greater OR (95% CI [1.6, 4.3]) of achieving TICI 2c/3 with additional passes compared to those who received SR for their first two passes. Similarly, those who used CT for their first two passes had 1.8OR (95% CI [1.1, 2.8]) of achieving TICI 2c/3 with additional passes compared to those who used SR. Conclusion In this SVIN Registry analysis, two failed passes with SR was associated with decreased likelihood of ultimately achieving TICI 2c/3 compared to two passes of CA or CT. These findings support additional attempts at reperfusion particularly in patients who were initially treated with CA or CT.