Introduction Mechanical thrombectomy (MT) remains the standard of care for patients presenting with acute ischemic stroke (AIS) due to large vessel occlusions (LVO). Favorable functional outcomes have been shown to be independently associated with early recanalization. Therefore, early initiation of antiplatelet (AP) medication may be beneficial in maintaining vessel recanalization or preventing recurrent stroke in high-risk individuals. Nonetheless, there is concern for increased risk of intracranial hemorrhage with peri-procedural AP therapy (with or without prior tPA). We sought to demonstrate the safety and functional outcomes of AP use within 24 hours following MT.

Methods We retrospectively reviewed prospectively collected data for consecutive patients who underwent MT for AIS between 2016-2020. Patient demographics, comorbidities, ASPECTS, TICI, AP and tPA use were collected. Patients were stratified into two groups, early (< 24 hours) or late (> 24 hours) based on when AP was initiated post-MT. Our primary outcome was safety, determined by the rate of symptomatic hemorrhagic transformation (HT) and inpatient mortality. Our secondary outcome was functional independence, defined as modified Rankin scale (mRS) < 2, at discharge, 30-days, and 90-days postoperatively. We compared the two cohorts using univariate analysis. Multiple imputations were used to create complete datasets for the missing data. Multivariable analysis was used to identify predictors for HT and functional outcomes. P-value <.05 was considered significant.

Results 190 patients met inclusion criteria (n=95 per group). Significant differences between the early and late groups included sex (61.1% versus 38.3% male), preoperative tPA (24.2% versus 75.8%), underwent angioplasty (23.2% versus 2.1%) and/or stent placement (20.0% versus 2.1%) and thrombectomy site (83.1% versus 97.9% anterior, 16.8% versus 2.1% posterior circulation) respectively. HT (symptomatic and asymptomatic) and inpatient mortality were not significantly different between groups. mRS was significantly lower at discharge (p < 0.001), 30-days (p = 0.011) and 90-days (p=0.024) in the early group. Functional independence was significantly higher in the early AP group at discharge (p = 0.015) and at 30-days (p = 0.006). Multivariable analysis demonstrated that early AP use was independently associated with significantly increased odds of achieving functional independence at discharge (OR =3.07, p = 0.007) and 30-days (OR = 5.78, p = 0.004). Early AP was not independently associated with increased odds of HT.

Conclusions Early AP initiation after MT in patients with AIS due to LVO was independently associated with significantly increased odds of better postoperative functional outcomes without increased odds of developing HT.

Disclosures H. Alexander: None. C. Claus: None. D. Tong: None. P. Kelkar: None. J. Griauzde: None. S. Teck: None. B. Richards: None.