Contribution of Large Bore Aspiration Catheter to Mechanical Thrombectomy

In recent years, mechanical thrombectomy and aspiration catheter technology have advanced significantly, with newer aspiration catheters (ACs) featuring larger lumens and improved outcomes. However, the specific features driving these improvements remain unclear. The aim of this study was to compare treatment outcomes between the latest-generation large-bore ACs (LACs) and conventional aspiration catheters (CACs) in patients undergoing mechanical thrombectomy.

In this retrospective single-center cohort study conducted at the authors' institution, we analyzed data from patients who underwent mechanical thrombectomy using ACs for internal carotid artery (ICA) or M1 segment middle cerebral artery (M1) occlusions between November 2017 and October 2022. Cases were classified into LAC (inner diameter ≥0.0710 inches) and CAC groups. Patient demographics and procedural features were evaluated, including 1st-pass effect (FPE), catheter-to-vessel match (CVM), and clot contact rates. Group comparisons were performed using the Mann-Whitney U-test or the chi-squared test. Univariate and multivariate logistic regression analyses were conducted for M1 occlusion cases treated with LACs.

The study cohort comprised 159 patients who underwent mechanical thrombectomy using ACs. The FPE success rate was significantly higher in the LAC group (52.8%) than in the CAC group (34.0%). With regard to the occlusion site, this rate was not significantly different between the LAC and CAC groups for ICA occlusions; however, for M1 occlusions, the LAC group demonstrated a significantly higher FPE rate than the CAC group (P = 0.009). CVM and clot contact rates were significantly higher in the LAC group (P = 0.001 and P ≤0.0001, respectively). In the LAC group, both CVM and clot contact were independently associated with FPE success in cases of M1 occlusion (odds ratio, 10.9; 95% confidence interval, 3.3-36.7; P <0.0001; odds ratio, 18.0; 95% confidence interval, 1.9-172.9; P = 0.013, respectively).

LACs yielded significantly better outcomes for M1 occlusions than CACs. The enhanced FPE rate appears attributable to 2 design advantages: increased bore size, which improves CVM, and superior trackability, which enhances clot contact. These findings suggest that, given the vessel diameter variations caused by factors beyond anatomical location, tailoring mechanical thrombectomy methods and device selection to individual vascular anatomy, rather than relying on fixed vessel-based criteria, may improve treatment outcomes.