Vessel deviation during stent retrieval predicts successful recanalization in stent-based mechanical thrombectomy for M2 occlusion

Purpose: This study aimed to clarify whether there is a relationship between vessel deviation during stent retrieval and successful recanalization in stent-based mechanical thrombectomy (MT) for M2 occlusion.

Methods: The video of the MT was reviewed for each of the 25 included patients with M2 occlusion. The vertical distance of vessel deviation at the time of stent retrieval was defined as D, and the diameter of the balloon guide catheter shown on the same screen was defined as B. The D/B ratio was calculated as an index of the vessel deviation. The presence or absence of successful recanalization (thrombolysis in cerebral infarction (TICI) score of 2b/3) was compared based on the D/B ratio and clinical factors.

Results: Of the 25 patients, successful recanalization was achieved in 18 (72%). The median D/B ratio with successful recanalization was 0.9, which was significantly lower than that without successful recanalization (2.5, p < 0.001, Mann-Whitney U test). Combined aspiration catheters were used in 24 cases. In nine (36%) cases, the tip of the aspiration catheter was in M2 during stent retrieval. The median D/B ratio with the position of the aspiration catheter tip in M1 or the internal carotid artery was 1.5, which was significantly higher than that with the position in M2 (0, p = 0.003, Mann-Whitney U test).

Conclusion: In stent-based MT for M2 occlusion, cases in which successful recanalization was achieved showed less vessel deviation during stent retrieval. To reduce vessel deviation, advancing the combined aspiration catheter up to M2 is useful.