Background The efficacy of thrombectomy for LVO presenting within 24 hours from LKW has been supported by multiple RCTs. Recent RCTs on thrombectomy in setting of large core infarcts demonstrate improved functional outcomes compared to medical management alone. However, these trials are restricted to patients presenting within 24 hours of LKW. The role of thrombectomy for LVO beyond 24 hours from LKW is unclear.

Methods A PRISMA guided systematic literature review of the MEDLINE and Cochrane databases was completed to identify all studies detailing the use of thrombectomy for AIS beyond 24hrs from last known well. Data on outcome measures were collected and included: rates of 90 day mRS score of 0-2, rates of symptomatic intracranial hemorrhage (sICH), 90 day mortality, and successful recanalization defined as mTICI 2b-3. Subsequent quantitative synthesis was performed with generation of pooled, weighted proportions using a random effects model.

Results In total 9 studies were identified with 563 patients undergoing MT for AIS beyond 24hrs. Successful recanalization defined as mTICI 2b-3 was achieved in 83% of cases (95% CI: 78.2 to 87.3%; I² = 33%). In 7.0% of cases, periprocedural sICH occurred (95% CI: 4.7% to 9.6%; I² = 0%). Furthermore, functional independence defined as an mRS 0-2 was achieved in 36.8% of patients (95% CI: 23.8 to 50.6%; I² = 85%). Lastly, 90 day mortality was observed in 26.1% of patients (95% CI: 22 to 30.5%; I² = 0.1%).

Conclusion Thrombectomy for LVO presenting beyond 24 hours from LKW can be effective and performed safely in carefully selected patients. Further prospective studies are needed to confirm our findings.

Disclosures G. Kohli: None. D. Schartz: None. N. Ellens: None. T. Bhalla: None. T. Mattingly: None. M. Bender: None.