Abstract 053: The Red 43 Intermediate Catheter For Aspiration Thrombectomy Of Distal Medium Vessel Occlusions (DMVOs): A Multicenter Experience.
Authors: Goyal N. , Khattar N. , Peterson J. , Dashti R. , Baumeister M. , Williams A. , Amadi I. , Ebersole K. , Sims J. , Madigan D. , Symonds D. , Gottschlich M. , Inoa V. , Frei D. , Fiorella D. 
Published: January 2025

Introduction
Recent clinical research has increasingly supported the effectiveness and safety of mechanical thrombectomy (MT) for treating occlusions in distal medium‐sized vessels. This underscores the necessity for specialized MT devices capable of navigating the tortuous anatomy of distal cerebrovascular vessels. The recently introduced RED 43 aspiration catheter can be used as a primary catheter for distal aspiration in acute ischemic stroke. In this multicenter study, we share our collective experience using the RED 43 catheter as the primary aspiration device for thrombectomy of DMVOs.

Methods
We identified consecutive patients with DMVOs who underwent primary aspiration thrombectomy using the RED 43 catheter from four high‐volume comprehensive stroke centers. We collected baseline clinical data, angiographic and clinical outcomes, as well as procedural complications. Cases with large vessel occlusion that were treated according to the standard of care and subsequently developed a DMVO were labeled as secondary DMVOs. The primary outcomes were the rate of first pass effect (FPE), defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score of 2c or 3 on the first pass, and the rates of successful recanalization, defined as mTICI ≥2b at the end of the procedure. We also obtained rates of good functional outcomes, symptomatic intracerebral hemorrhage (ICH), asymptomatic ICH, subarachnoid hemorrhage (SAH), and in‐hospital mortality.

Results
We identified 102 consecutive cases of DMVOs undergoing primary aspiration thrombectomy using the RED 43 catheter. The mean age was 70 (SD: 14) years. The medianNIHSS score was 9 (IQR 6‐14), and the median ASPECTS was 9 (IQR 8‐10). Among these, 79 cases were primary DMVOs, and 23 were secondary DMVOs. The primary occlusion locations where the RED 43 catheter was used were as follows: distal M2 MCA segment in 41 cases (40.2%), M3 MCA segment in 29 cases (28.4%), M4 MCA segment in 5 cases (4.9%), A1 ACA in 4 cases (3.9%), A2/A3 ACA in 12 cases (11.8%), and P1 PCA in 8 cases (7.8%). The rate of first pass effect (FPE) (mTICI 2c or 3 on the first pass) using the RED 43 aspiration catheter was 57% (45/79) for primary DMVOs and 61% (14/23) for secondary DMVOs. The rate of successful recanalization (mTICI ≥2b at the end of the procedure) was 83% (66/79) for primary DMVOs and 87% (20/23) for secondary DMVOs. A good functional outcome (mRS 0‐2 at 3 months) was observed in 57% of patients. One patient experienced symptomatic ICH, and two patients died during hospitalization. Asymptomatic ICH and asymptomatic SAH were observed in 5 patients (4.9%) and 7 patients (6.9%), respectively.

Conclusion
Our study demonstrates the safety and efficacy of the RED 43 catheter for aspiration thrombectomy of both primary and secondary DMVOs, with good rates of FPE and successful recanalization, and an excellent safety profile.