Outcomes of mechanical thrombectomy in acute stroke due to primary embolic middle cerebral artery M2 occlusions: a comparison of late versus early windows.

BACKGROUND

Current guidelines consider mechanical thrombectomy (MT) reasonable for M2 segment middle cerebral artery (MCA) occlusions within 6 h of symptom onset, yet the impact of delayed intervention in this population remains unclear.

OBJECTIVES

This study compared effectiveness and safety outcomes of MT performed in late (>6 h) versus early (⩽6 h) treatment windows in patients with acute primary embolic M2 occlusions.

DESIGN

We retrospectively analyzed patients with primary embolic M2 occlusions treated with MT within 24 h of onset from the ARTISTA (A Registry for Thrombectomy In Stroke Therapy from Andalusia) registry (2017-2024) in Seville-Huelva, Spain.

METHODS

Outcomes compared between late and early treatment groups included good outcome (90-day modified Rankin Scale (mRS) 0-2 or return to prestroke mRS), futile recanalization (FR; 90-day mRS >2 despite successful recanalization), successful recanalization (modified Thrombolysis in Cerebral Infarction ⩾2b), and symptomatic intracranial hemorrhage (sICH). Multivariable logistic regression and inverse probability of treatment weighting (IPTW) analyses were performed to evaluate associations between treatment window and MT outcomes.

RESULTS

Among 524 patients (median age 76, 48.3% women), 207 (39.5%) underwent MT in the late window. Late treatment showed numerically lower rates of good outcome (58.9% vs 64.4%) and higher rates of FR (37.8% vs 32.5%) and sICH (3.4% vs 3.2%), though none were statistically significant (all p ⩾0.211). Successful recanalization rates were nearly identical between the late and early windows (95.7% vs 95.6%; p = 0.970). IPTW-adjusted analyses also found no significant differences in good outcome (adjusted odds ratio (aOR), 0.82; 95% confidence interval (CI), 0.39-1.73; p = 0.600) or FR (aOR, 1.19; 95% CI, 0.56-2.50; p = 0.653) at 90 days.

CONCLUSION

In this multicenter real-world cohort, MT performed beyond 6 h showed effectiveness and safety outcomes comparable to early-window intervention in patients with primary embolic MCA M2 occlusions.