Incomplete mechanical recanalization of middle cerebral artery occlusions facilitates endogenous recanalization within 5 h.
OBJECTIVE
Successful revascularization can often improve functional outcome after large intracranial arterial occlusions. However, incomplete or unsuccessful recanalization is often the end result after attempted mechanical thrombectomy. A study was undertaken to determine whether partial recanalization of proximal isolated middle cerebral artery (MCA) occlusions facilitates endogenous thrombolysis and spontaneous recanalization.


METHODS
We retrospectively analyzed consecutive patients with acute ischemic stroke undergoing mechanical thrombectomy using the Merci Retriever System for occlusions involving any portion of the M1 segment of the MCA. Only those patients with a residual obstruction of the proximal MCA segments were included. The rates of facilitated endogenous recanalization (FER₅) by imaging within the 5 h following intervention were compared in patients with partial proximal recanalization and those in whom recanalization was unsuccessful.


RESULTS
Forty-two patients were included in the analysis. Twenty-six patients had good recanalization of the proximal aspect of the target lesion with an arterial occlusive lesion score of 2 or 3 but a residual partial or total occlusion of the MCA, while 16 patients failed to recanalize any portion of the target occlusion. Twelve patients (46%) in the first group and only one (5.9%) in the second group had facilitated endogenous recanalization on interval imaging 5 h after intervention (OR 12.9, 95% CI 1.5 to 112.2). Nine patients with proximal recanalization had good clinical outcomes at discharge (mRS ≤2) compared with none without recanalization (p=0.01), but FER did not have a relationship with clinical outcome.


CONCLUSIONS
Despite initially incomplete proximal mechanical thrombectomy, nearly half of all patients with residual M1 occlusions will undergo further endogenous recanalization within the subsequent 5 h.
Department of Medicine, Madigan Army Medical Center, Tacoma, Washington 98431, USA. yincer@yahoo.com
Yince
Y
Loh
Zhongsong
Z
Shi
David
D
Liebeskind
Reza
R
Jahan
Nestor
N
Gonzalez
Paul M
PM
Vespa
Sidney
S
Starkman
Jeffrey L
JL
Saver
Satoshi
S
Tateshima
Fernando
F
Vinuela
Gary
G
Duckwiler
D000368:Aged; D000369:Aged, 80 and over; D002548:Cerebral Revascularization / Q000379:methods*; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D017131:Thrombectomy / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome