Clinical Outcomes in Middle Cerebral Artery Trunk Occlusions Versus Secondary Division Occlusions After Mechanical Thrombectomy: Pooled Analysis of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI Trials

• Published in: Stroke (1970) Vol. 41; no. 5; pp. 953 - 960
• Main Authors: SHI, Zhong-Song, LOH, Yince, WALKER, Gary, DUCKWILER, Gary R
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01-05-2010
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Brain Ischemia - complications; Brain Ischemia - physiopathology; Brain Ischemia - surgery; Cohort Studies; Embolectomy - methods; Female; Humans; Infarction, Middle Cerebral Artery - complications; Infarction, Middle Cerebral Artery - physiopathology; Infarction, Middle Cerebral Artery - surgery; Intracranial Embolism - complications; Intracranial Embolism - physiopathology; Intracranial Embolism - surgery; Male; Medical sciences; Middle Aged; Neurology; Neuropharmacology; Neuroprotective agent; Pharmacology. Drug treatments; Retrospective Studies; Thrombectomy - methods; Treatment Outcome; Vascular diseases and vascular malformations of the nervous system; Trunk; Stroke; Nervous system diseases; Prognosis; thrombectomy; Middle cerebral artery; Cardiovascular disease; Endovascular route; endovascular treatment; Cerebral disorder; Vascular disease; Treatment; acute stroke; Exeresis; Central nervous system disease; Brain ischemia; Comparative study; Cerebrovascular disease; outcome
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/STROKEAHA.109.571943

The benefit of endovascular revascularization of patients with acute ischemic stroke with middle cerebral artery (MCA) secondary division (M2) occlusions as compared with MCA trunk (M1) occlusions is not known. In this analysis, we compared revascularization status and clinical outcomes in patients with angiographically confirmed MCA M1 versus isolated M2 occlusions treated with mechanical thrombectomy using the Merci Retriever devices.
We retrospectively analyzed the pooled data of patients with MCA strokes from the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI trials. Patient data were dichotomized into 2 groups: MCA M1 occlusions and isolated M2 occlusions. Baseline characteristics, revascularization rates, hemorrhage rates, complications, outcomes, and mortality were evaluated for both groups.
Of 178 patients with MCA occlusion treated in the MERCI and Multi MERCI trials, 84.3% had M1 lesions and 15.7% had isolated M2 lesions. Patients with isolated M2 occlusions were revascularized at a higher rate, required a lower mean number of passes, and were associated with a trend toward shorter mean procedure time than patients with M1 occlusions. No statistically significant differences were found between M2 and M1 groups for symptomatic hemorrhage, clinically significant procedural adverse events, favorable 90-day outcome, or 90-day mortality, although in all instances, the M2 outcomes were numerically better than those in M1 subjects. In multivariate analysis, final revascularization was the strongest independent predictor of good outcome at 90 days.
Patients with both MCA M1 occlusions and isolated M2 occlusions can achieve a relatively high rate of revascularization and favorable clinical outcomes after mechanical thrombectomy. In fact, patients with isolated M2 occlusions had a higher rate of revascularization, required fewer passes, and had no increased complications compared with patients with M1 occlusions.