Endovascular Thrombectomy Benefits Observed 6 to 24 Hours Since Last Known Well

Tudor Jovin, MD

Data from a recent study suggest that endovascular thrombectomy (ET) benefits patients with acute ischemic stroke (IS) across the 6- to 24-hour time window. These findings were presented at the American Stroke Association's International Stroke Conference (ISC) 2021, March 17-19, by Tudor Jovin, MD, medical director, Cooper Neurological Institute, and chairman and chief of neurology, Cooper University Health Care.

In the Analysis Of Pooled Data From Randomized Studies Of Thrombectomy More Than 6 Hours After Last Known Well (AURORA) collaboration, Jovin and colleagues analyzed data from 6 randomized trials that examined ET in anterior circulation proximal large vessel occlusion (LVO) stroke beyond 6 hours and up to 24 hours from time last seen well (TSLW). They sought to more precisely define the point estimate of ET benefit and address remaining questions regarding subgroups through meta-analysis of individual patient data. 

"So, why 6 hours? This cutoff point is somewhat arbitrarily chosen but it is highly consequential. It really represents the point of demarcation between early and late time window, and it is consequential because virtually all guidelines recommend different approaches to patients whether they present within 6 hours or beyond 6 hours. Beyond 6 hours, treatment selection is more restricted,” Jovin said in his presentation.

Primary outcome of the AURORA collaboration was reduced disability on the modified Rankin scale (mRS) at 90 days. Safety outcomes, including symptomatic intracerebral hemorrhage (sICH) and mortality within 90 days were also measured. Subgroup analyses were also conducted and functional independence, as defined by a score of 0-2 on the mRS, was also assessed.

READ MORE: Improving Access to Endovascular Thrombectomy for Acute Ischemic Stroke

Altogether, Jovin and colleagues analyzed data from 505 participants, 266 with intervention and 239 as control. They determined benefit of ET, with an adjusted common odds ratio (cOR) of 2.54 (95% CI, 1.82-3.54; P <.0001). The number needed to treat to reduce disability at least 1 level on mRS was 3.

The researchers found that 81.0% (n = 216) of ET patients had successful revascularization. No significant differences were seen in mortality between intervention (16.5%; n = 44) and control (19.3%; n = 46) groups, or sICH between intervention (5.3%; n = 14) and control groups (3.3%; n = 8).

No heterogeneity of treatment effect across pre-specified subgroups was observed, except for a stronger treatment effect in patients treated withing the 12- to 24-hour time window (cOR, 5.86 [95% CI, 3.14-10.94]) compared to those treated within the 6-to-12-hour time window (cOR, 1.76 [95% CI, 1.18-2.62]; P = .006).

Jovin and colleagues also found that thrombectomy benefitted more in participants at least 80 years in age (cOR, 2.74), participants with an onset of symptoms beyond 6 hours from randomization (cOR, 2.78) and in participants with a baseline Alberta Stroke Program Early CT Score (ASPECTS) score of at least 8 (cOR, 2.69).

“In conclusion, we can say that ET initiated beyond 6 hours from TLSW is no less effective than treatment initiated within 6 hours. It has a safety profile no different than that observed with ET performed within 6 hours. The effectiveness is maintained across all groups,” Jovin concluded.

REFERENCE
Jovin T, Nogueira R, Lansberg M, et al. Thrombectomy for anterior circulation stroke beyond 6 hours from time last known well: Final results of the Aurora (analysis of pooled data from randomized studies of thrombectomy more than 6 hours after last known well) collaboration. Presented at International Stroke Conference 2021; March 17-19. Abstract LB 8.