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