Bridging Therapy Effective for Stroke With M1 Occlusions

Pierre Seners, MD, PhD

Data from a multicenter retrospective observational study suggest there are no significant differences in overall outcomes in the treatment of stroke with large vessel occlusion (LVO) when using bridging therapy or intravenous thrombolysis (IVT) alone. The findings imply that intended bridging therapy may be beneficial in M1 occlusions, while the benefit-risk profile may favor IVT alone in M2 occlusions.

When compared with IVT alone, bridging therapy—otherwise described as IVT followed by endovascular treatment&mdash;was shown to not be associated with excellent outcome (odds ratio [OR], 0.96; 95% CI, 0.75—1.24; P = .76). It was, however, associated with symptomatic intracranial hemorrhage (sICH; OR, 3.01; 95% CI, 1.77—5.11; P <.0001).

Although the overall outcomes for each therapy were similar, occlusion site was a strong modifier of the effect of bridging therapy on outcome (P <.0001). Study author Pierre Seners, MD, PhD, neurology department, Sainte-Anne Hospital, and colleagues noted that bridging therapy was associated with higher odds of excellent outcome in proximal M1 occlusions (OR, 3.26; 95% CI, 1.67—6.35; P = .0006) and distal M1 occlusions (OR, 1.69; 95% CI, 1.01—2.82; P = .04), but with lower odds of excellent outcome for M2 occlusions (OR, 0.53; 95% CI, 0.38—0.75; P = .0003).

The researchers also noted that the bridging therapy was associated with higher rates of sICH only in M2 occlusions (OR, 4.40; 95% CI, 2.20—8.83; P <.0001).

“Two salient findings emerged. First, bridging therapy —as compared to IVT alone– did not result in better functional outcomes, and was associated with higher odds of any ICH and sICH, in the overall population. Second, occlusion site significantly modified the effect of bridging therapy, namely the latter was associated with better functional outcome in proximal or distal M1 occlusions, and with worse functional outcome and higher odds of any ICH or sICH for M2 occlusions,” Seners and investigators concluded.

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The collection of data was from patients with stroke admitted to 45 French stroke centers between 2006 and 2018 who fulfilled inclusion criteria. More specifically, patients had a baseline admission National Institute of Health Stroke Scale (NIHSS) score of <5, LVO on pre-treatment vascular imaging, and were treated with IVT (alteplase only) with or without intended additional EVT. Pretreatment vascular imaging included internal carotid artery (ICA), M1, second segment of middle cerebral artery (M2), and basilar artery.

The study included 598 patients, 214 in the bridging group and 384 in the IVT group. Seners and coauthors used excellent functional outcome, defined as a score between 0-1 on the modified Rankin Scale (mRS), as a more appropriate goal for mild strokes. Good functional outcome (mRS 0-2) was used as a secondary outcome, and 24-hour follow-ups for safety measures evaluated the incidence of ICH and sICH.

The group noted that dedicated randomized controlled trials would be necessary to offer a definitive answer to “the critical question” of which reperfusion strategy is best for minor strokes with LVO, acknowledging that 2 such trials are in preparation and/or underway—ENDO-LOW (NCT04167525) and In Extremis/MOSTE (NCT03796468).

REFERENCE

Seners P, Perrin C, Lapergue B; Bridging therapy or IV thrombolysis in minor stroke with large vessel occlusion. Ann Neurol. Published online April 29, 2020. doi: 10.1002/ana.25756.