Thrombectomy for M2 Occlusions: Predictors of Successful and Futile Recanalization
Authors: Kniep Helge , Meyer Lukas , Broocks Gabriel , Bechstein Matthias , Heitkamp Christian , Winkelmeier Laurens , Faizy Tobias , Brekenfeld Caspar , Flottmann Fabian , Deb-Chatterji Milani , Alegiani Anna , Hanning Uta , Thomalla Götz , Fiehler Jens , Gellißen Susanne , Röther Joachim , Eckert Bernd , Braun Michael , Hamann Gerhard F. , Siebert Eberhard , Nolte Christian , Zweynert Sarah , Bohner Georg , Berrouschot Jörg , Bormann Albrecht , Kraemer Christoffer , Leischner Hannes , Hattingen Jörg , Petersen Martina , Stögbauer Florian , Boeckh-Behrens Tobias , Wunderlich Silke , Ludolph Alexander , Henn Karl-Heinz , Gerloff Christian , Schell Maximilian , Reich Arno , Nikoubashman Omid , Dorn Franziska , Petzold Gabor , Liman Jan , Schäfer Jan Hendrik , Keil Fee , Gröschel Klaus , Uphaus Timo , Schellinger Peter , Borggrefe Jan , Tiedt Steffen , Kellert Lars , Trumm Christoph , Ernemann Ulrike , Poli Sven , Riedel Christian , Ernst Marielle Sophie 
Published: July 2023

BACKGROUND:
Patient-specific factors associated with successful recanalization in mechanical thrombectomy (MT) have been evaluated for acute ischemic stroke with large vessel occlusion. However, MT for M2 occlusions is still a matter of debate, and predictors of successful and futile recanalization have not been assessed in detail. We sought to identify predictors of recanalization success in patients with M2 occlusions undergoing MT based on large-scale clinical data.

METHODS:
All patients prospectively enrolled in the German Stroke Registry (May, 2015 to December, 2021) were screened (N=13 082). Inclusion criteria for the complete case analysis were isolated M2 occlusions. Standard descriptive statistics and multivariable logistic regression analysis were used to identify factors associated with successful recanalization (Thrombolysis in Cerebral Infarction [TICI]≥2b), complete recanalization (TICI=3) and futile recanalization (TICI≥2b with 90-day modified Rankin Scale [mRS] score >2).

RESULTS:

One thousand two hundred ninety-four patients were included, thereof 439 (33.9%) with TICI=2b and 643 (49.7%) with TICI=3. Five hundred sixty-nine (44%) patients had good functional outcome (90-day mRS score ≤2). In multivariable logistic regression, general anesthesia (adjusted odds ratio [aOR], 1.47 [95% CI, 1.05–2.09];
P
<0.05) was associated with higher probability of TICI≥2b while intraprocedural change from local to general anesthesia (aOR, 0.49 [0.26–0.95];
P
<0.05) and higher pre-mRS (aOR, 0.75 [0.67–0.85];
P
<0.001) lowered probability of successful recanalization. Futile recanalization was associated with higher age (aOR, 1.05 [1.04–1.07];
P
<0.001), higher prestroke mRS (aOR, 3.12 [2.49–3.91];
P
<0.001), higher NIHSS at admission (aOR, 1.11 [1.08–1.14];
P
<0.001), diabetes (aOR, 1.96 [1.38–2.8];
P
<0.001), higher number of passes (aOR, 1.29 [1.14–1.46];
P
<0.001), and adverse events (aOR, 1.82 [1.2–2.74];
P
<0.01). Higher Alberta Stroke Program Early CT Score (aOR, 0.85 [0.76–0.94];
P
<0.01) and IV thrombolysis (aOR, 0.71 [0.52–0.97];
P
<0.05) reduced risk of futile recanalization.

CONCLUSIONS:
In patients with M2 occlusions, successful recanalization was significantly associated with general anesthesia and low prestroke mRS, while intraprocedural change from conscious sedation to general anesthesia increased risk of unsuccessful recanalization, presumably caused by difficult anatomy and movement of patients in these cases. Futile recanalization was associated with severe prestroke mRS, comorbidity diabetes, number of passes and adverse events during treatment. IV thrombolysis reduced the risk of futile recanalization.