A Comparison of Mechanical Thrombectomy in the M1 and M2 Segments of the Middle Cerebral Artery: A Review of 585 Consecutive Patients

Abstract

Background: Mechanical thrombectomy for anterior-circulation large-vessel occlusion has shown benefit; however, the question of whether this technique is safe and effective in the distal vasculature remains unanswered. We sought to compare the outcome data from mechanical thrombectomy of the M2 branches of the middle cerebral artery (MCA) with those of the M1 segment. Methods: We performed a retrospective analysis of prospectively collected data of patients with acute ischaemic stroke undergoing mechanical thrombectomy of isolated M1 or M2 branches of the MCA between August 2008 and August 2016. Results: We identified 585 patients, 479 with M1 occlusions and 106 with M2 occlusions. The average age was 72 ± 12.8 and 68 ± 13.8 years, respectively (p = 0.007). The baseline Alberta Stroke Program Early Computed Tomographic (ASPECT) score was similar in both cohorts, but patients with M1 occlusions presented with higher mean National Institutes of Health Stroke Scale (NIHSS) scores of 15.7 compared to 11.8 (p < 0.001). There was no significant difference in the average procedure time for each cohort; fewer thrombectomy attempts were required in the M2 cohort (2.3 vs. 1.8, p = 0.0004), but the overall time to recanalization was longer in the M2 cohort (353 vs. 399 min, p < 0.001). Similar rates of successful reperfusion (Thrombolysis in Ischaemic Stroke score [TICI] ≥2b 88.5 vs. 90.5%, p = 0.612) were seen, but food outcome (modified Rankin Scale ≤2) was lower in M1 occlusions (37.2 vs. 54.3%, p < 0.001). Rates of symptomatic intracranial haemorrhage were similar. Conclusion: Good clinical outcomes can be achieved for both groups with no significant differences in procedure length, final TICI recanalization rates or intracranial haemorrhage between the M1 and M2 cohorts.

ADAPT technique in ischemic stroke treatment of M2 middle cerebral artery occlusions in comparison to M1 occlusions: Post hoc analysis of the PROMISE study

“…10 Several retrospective studies examining EVT for M2 occlusions found similar or greater rates of successful revascularization (mTICI 2b/3) and good functional outcome (mRS 0-2) at follow-up as compared to M1 occlusions. [11][12][13][14] In a retrospective study of patients with M2 occlusions, Sarraj et al 15 found that EVT resulted in significantly greater odds of functional improvement compared to medical management. Additionally, a meta-analysis of data from the HERMES collaboration examining outcomes of EVT in M2 MCA occlusions compared to medical management found a treatment effect in favor of EVT regarding good functional outcome (mRS 0-2 at 90 days).…”

Microcatheter infusion of bolus-dose tirofiban for acute ischemic stroke due to distal intracranial artery occlusion

“…[ 5 , 10 ] However, because of the circuit in which the distal artery is included and the small vascular diameter, it is difficult for existing techniques, including aspiration (even via aspiration catheter), to reach the desired location and provide effective therapy. [ 6 ] Recently, micro-ADAPT technology was developed. [ 15 ] Although this technology provides a rapid and effective technique for thrombus extraction from the A3, M3, and P3 segments, it is difficult for finer vascular aspiration catheters to be positioned in contact with the thrombus for suction.…”

“…These reports provide evidence suggesting that this therapy is insufficient is some cases and is associated with a considerable risk of operation-related complications such as vasospasm, dissection, and perioperative bleeding. [ 5 , 6 , 8 – 12 ] Tirofiban is a reversible, nonpeptide platelet glycoprotein IIb/IIIa receptor antagonist. While it is mainly used to treat unstable angina and in coronary angioplasty, its potential use for acute thrombosis and stent implantation during neuro-interventional surgery has been reported.…”

Mechanical thrombectomy for recurrent large vessel occlusion

“…There is now a growing body of evidence which could support the idea of making mechanical thrombectomy available to more patients than at present. This could include treating patients with lower NIHSS scores at admission [6][7][8][9], those with more distal occlusions [10][11][12][13][14], patients with larger infarct volumes at presentation [15], and patients presenting more than 6 h after the event [16,17].…”