Is Intra-arterial Thrombolysis Beneficial for M2 Occlusions? Subgroup Analysis of the PROACT II Trial

Keywords: clinical trial, stroke, middle cerebral artery, thrombolysis, tissue plasminogen activator

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     The role of endovascular therapy in the management of acute ischemic stroke caused by occlusion of M2 divisions of the MCA is debatable.
     Through a subgroup analysis of the prospective randomized PROACT II trial, we sought to compare the outcomes of M2 occlusions in the placebo and treatment arms.
     Forty-four patients with solitary M2 occlusions, 14 in the placebo and 30 in the treatment group, were enrolled in the trial.
     All cases of solitary M2 occlusion were selected from the PROACT II database and classified according to sidedness, anatomy, extent of involved MCA territory, and clot location. Favorable outcome was defined as mRS = 2 at 3 months. Baseline patient characteristics (sex, age, NIHSS, premorbid mRS, diabetes, glucose level) were also recorded and compared between the 2 arms.
     Successful angiographic reperfusion (TICI 2-3) was achieved in 16.7% of placebo and 53.6% of treated patients (p=0.04). A favorable clinical outcome at 3 months was observed in 28.6% and 53.3% of patients, respectively (p=0.19). Baseline characteristics were similar between the 2 groups. No significant differences in outcome were observed in any of the prespecified subgroups.
     This was a subgroup analysis from a prospective trial.
     In addition to the clear benefit of intra-arterial thrombolysis in terms of angiographic reperfusion of M2 occlusions, there was a trend toward improved clinical outcomes in treated patients.
     Given that this subgroup analysis was likely underpowered, further studies are required to understand the role of intra-arterial therapy in the management of acute M2 occlusions.


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