Mechanical Thrombectomy in Medium Vessel Occlusions

Abstract

Background and Purpose: Mechanical thrombectomy techniques for intracranial medium vessel occlusions (MeVOs) have evolved in recent years, although the optimal approach is still unclear. The aim of this study was to investigate the effectiveness and safety of mechanical thrombectomy in MeVOs using mini (0.017 inches microcatheter compatible) stent retrievers combined with low-profile (0.035 inches distal inner diameter) distal aspiration catheters through the blind exchange/mini-pinning (BEMP) technique compared with mini stent retrievers alone. Methods: Retrospective review of a prospectively maintained database of patients treated with the BEMP technique or mini stent retriever alone for intracranial MeVOs from 2017 to 2020 in a comprehensive stroke center. Both groups were compared about baseline characteristics, occlusion site, clinical presentation, clot cause, procedural outcomes (MeVO first-pass and final expanded Thrombolysis in Cerebral Ischemia score, the mini stent retriever used, number of passes with the front-line approach, and need of rescue therapy), safety outcomes (emboli to unwanted territories and hemorrhagic complications), and clinical outcomes at 90 days. Multivariable logistic regression analysis was performed with potential predictors of vessel recanalization to find independent variables associated with MeVO first-pass expanded Thrombolysis in Cerebral Ischemia 2c/3 recanalization. Results: We reviewed 102 patients/106 MeVOs treated with the BEMP technique (n=56) or mini stent retriever (n=50). There was a higher rate of MeVO first-pass expanded Thrombolysis in Cerebral Ischemia 2c/3 recanalization (57% versus 34%, P =0.017), lower need of rescue therapy (7.1% versus 22%, P =0.028), and lower rate of emboli to new territory (1.8% versus 12%, P =0.035) and symptomatic intracranial hemorrhage (1.9% versus 12.8%, P =0.038) with the BEMP technique. After multivariable analysis, the sole independent factor associated to MeVO first-pass expanded Thrombolysis in Cerebral Ischemia 2c/3 recanalization was the BEMP technique (odds ratio, 2.72 [95% CI, 1.19–6.22]; P =0.018). Conclusions: In the setting of MeVOs, the BEMP technique may lead to higher rates of the first-pass recanalization and a lower incidence of symptomatic intracranial hemorrhage than mini stent retrievers alone.

Blind Exchange With Mini-Pinning Technique Using the Tron Stent Retriever for Middle Cerebral Artery M2 Occlusion Thrombectomy in Acute Ischemic Stroke

“…It has been reported that the outer diameters of MCA M2 and M3 segments are 1.4–2.3 and 0.8–1.5 mm, respectively ( 33 ). The diameters of previous reported mini-stent retrievers are 3–3.5 mm ( 1 , 2 , 6 ), which is considered slightly large for MCA M2 or M3 segments ( 34 ). Since the Tron stent retriever has a 2-mm profile, it can be safely deployed even in non-dominant distal M2 occlusions with a small diameter.…”

“…The subsequent straightening of the vessels that can be achieved by gently pulling the retriever wire greatly facilitates overcoming the barriers to M2 navigation of DACs. Pérez-García et al reported that the BEMP technique using 3 × 15-mm, 3 × 20-mm, or 3.5 × 28-mm stent retrievers led to higher the first-pass eTICI 2c/3 recanalization rates (57.1%) and a lower incidence of sICH (1.9%) than that using mini-stent retrievers alone in thrombectomy for intracranial MeVOs ( 2 ). In our BEMP technique using 2 × 15-mm or 4 × 20-mm Tron stent retrievers, the first-pass eTICI 2c/3 recanalization was observed in 47% of the M2 vessels, and no sICH was seen for MCA M2 occlusion.…”

“…The usefulness of the blind exchange with mini-pinning (BEMP) technique has recently been reported for mechanical thrombectomy in patients with acute ischemic stroke (AIS) owing to medium vessel occlusion (MeVO), i.e., occlusions of the M2/M3 middle cerebral artery (MCA), A2/A3 anterior cerebral artery, and P2/P3 posterior cerebral artery segments ( 1 , 2 ).…”

“…The BEMP technique, which is the blind catheter exchange technique and originally devised using a Trevo 3 × 20-mm retriever (Stryker, Fremont, CA, USA) delivery wire to advance the thromboaspiration catheter and the pinning technique with small devices (“mini-pinning”) for thrombectomy of intracranial distal occlusions, has been reported to be helpful and safe for optimizing procedural performance when treating MeVO ( 1 , 2 ). Although original mini-pinning was required to pull the stent retriever slightly and lock the stent retriever and aspiration catheter ( 1 ), performing this operation for MCA distal M2 occlusion is challenging.…”

“…Although the traditional combination technique using a Tron stent retriever with a 3MAX or 4MAX aspiration catheter may be effective in enhancing the first-pass effect (FPE) ( 7 ) in MCA M2 occlusion thrombectomy, we occasionally experience that a 4MAX aspiration catheter is often outsized for the target vessel, and that a 3MAX aspiration catheter for the target thrombus volume is insufficient when trying to engage these aspiration catheters proximal to the thrombus. In the BEMP technique, the aspiration catheter (3MAX or 4MAX aspiration catheter) can be determined after confirming the target vessel diameter ( 1 , 2 ). Therefore, the BEMP technique using Tron stent retriever has potential as an effective and safe treatment for MeVO, including occlusion of the MCA M2.…”