Gradual expansion of stent retriever in mechanical thrombectomy for curved middle cerebral artery: structural findings of the stent for predictable recanalization results

Abstract

Background Trevo Provue stent retriever with visible struts under fluoroscopy may be useful in identifying the optimal position and expansion of the stent during the procedure. This study aimed to demonstrate and analyze changes in the segmental diameter of a radio-opaque stent retriever after deployment according to recanalization results, and its relationship with the angle of the occluded segment of the middle cerebral artery (MCA). Methods Forty-one patients who underwent mechanical thrombectomy using a Trevo stent retriever were divided into two groups according to Thrombolysis in Cerebral Infarction (TICI) score (TICI 0-2a and TICI 2b/3). The proximal (Pt), middle (Mt), and distal diameter (Dt) of the deployed stent, at three post-deployment waiting times (t = 0, 3, and 5 min), were measured, and ratios of Mt to Pt (Mt/Pt) and of Mt to Dt (Mt/Dt) were calculated. Results TICI 2b/3 was achieved in 31 patients (75.6%) and TICI 0-2a in 10 patients (24.4%). In the TICI 2b/3 group, both changes of Mt/Pt (P < 0.001) and Mt/Dt (P = 0.001) until 3 min were significant and all Mt/Pt (each P < 0.01), M3/D3 (P = 0.014), and M5/D5 (P = 0.012) were significantly larger than those in the TICI 0-2a group. The angle of the MCA was significantly correlated with Mt/Pt and Mt/Dt (P < 0.001). Conclusion The diameter of the stent retriever after deployment was associated with the recanalization results in mechanical thrombectomy following MCA occlusion.