Bridging Thrombolysis and ASPECTS in Patients With Stroke Treated With Endovascular Thrombectomy

In patients with stroke with large-vessel occlusion and extensive ischemic change denoted by low Alberta Stroke Programme Early Computed Tomography Score (ASPECTS), the role of bridging thrombolysis before endovascular thrombectomy (EVT) is still to be determined. We aimed to examine the impact of ischemic change on clinical outcomes and how this is modified by bridging thrombolysis in patients treated with EVT.

Consecutive patients undergoing anterior circulation EVT from a prospectively collected registry were included in this retrospective analysis. ASPECTS was evaluated from baseline noncontrast computed tomography scans with lower scores indicating larger areas of ischemic change. Outcome measures included symptomatic intracranial hemorrhage and functional independence (modified Rankin Scale score, 0-2) at day 90. Multivariable logistic regression models with interaction terms between ASPECTS and bridging thrombolysis were created. ASPECTS was treated as numeric variable in the primary analysis and trichotomized (ASPECTS ≤5, 6-8, 9-10) in a sensitivity analysis.

A total of 872 patients undergoing EVT (384 women, mean±SD age of 67±15, baseline National Institute of Health Stroke Scale 16 [interquartile range, 11-20]) were included. A total of 549 (63%) patients were transferred from primary stroke centers for EVT and 436 (50%) received bridging intravenous thrombolysis with alteplase. On baseline computed tomography scan, median [interquartile range] ASPECTS was 8 [7-9], with 408 (47%) having minimal (ASPECTS 9-10), 376 (43%) moderate (ASPECTS 6-8), and 88 (10%) extensive (ASPECTS ≤5) ischemic change. With decreasing numeric ASPECTS, the probability of functional independence reduced (ASPECTS main effect adjusted odds ratio, 1.36 [95% CI, 1.23-1.52]; P<0.001), but this was attenuated in those with bridging thrombolysis (interaction P=0.046). This interaction was significant for patients transferred to the EVT center after thrombolysis (interaction P=0.03) but not for patients presenting directly to the EVT center (interaction P=0.46). The interaction between ASPECTS and bridging thrombolysis was not significant when ASPECTS was split into the 3 categories (P=0.35).

In a cohort of patients undergoing EVT where most were transferred from a primary stroke center, ischemic change was associated with decreased probability functional independence, but this effect was attenuated with bridging thrombolysis. These results suggest that patients with large areas of ischemic change may still benefit from the earliest possible reperfusion afforded by bridging thrombolysis.