Efficacy and Safety of Mechanical Thrombectomy for Occlusion of the Second Segment of the Middle Cerebral Artery : Retrospective Analysis of the Tama-REgistry of Acute endovascular Thrombectomy (TREAT).

Background: The efficacy of mechanical thrombectomy in the treatment of occlusions of the second segment of the middle cerebral artery (M2) has not been firmly established.

Methods: This study analyzed data from patients who had undergone mechanical thrombectomy for the first segment of the middle cerebral artery (M1) and M2 occlusion from the Tama-REgistry of Acute endovascular Thrombectomy (TREAT) between January 2015 and March 2017, which is a multicenter database in the Tama area of Tokyo, Japan. The M1 and M2 occlusions were compared in order to evaluate the safety and efficacy of M2 thrombectomy.

Results: A total of 515 patients were registered, whereby 160 patients with M1 occlusion and 51 patients with M2 occlusion were included. While the puncture-to-reperfusion time was longer in the M2 occlusions (median 43 min, range 30-61 min vs. median 60 min, range 38-79 min, p = 0.01), no significant differences were seen in the proportion of patients with successful reperfusion, postoperative hemorrhagic complications and good outcome (modified Rankin scale ≤2 at 90 days). Younger age was the only independent factor associated with good outcome in patients with M2 occlusions as determined by the multivariate analysis (p = 0.033, odds ratio 0.91, 95% confidence interval 0.83-0.99).

Conclusions: The outcome and the safety profile of mechanical thrombectomy for M2 occlusions are favorable and comparable to those of the M1 occlusion thrombectomy.