Vessel Curvature and Microcatheter–Detachable Coil Compatibility in Arterial Coil Embolization

Purpose: This study examined whether sharp vessel angulation (≥90–180°) and microcatheter–detachable coil compatibility independently increase coil maldelivery in non-neuro arterial embolization, and how these factors affect technical failure and salvage strategies. Materials and Methods: A single-center, IRB-approved analysis from February 2023 to December 2024 included 451 arterial branch–detachable coil combinations (BCCs) in 119 patients (mean age 64 years, range 32–87). Angulations of 90–180° at the proximal catheter segment and distal tip were evaluated on digital subtraction angiography. Technical failure was defined as inability to deploy the coil as intended, including unraveling or coil shape distortion. A 1:3 propensity score matching (28 failed vs 61 successful BCCs) balanced coil features and target-vessel factors. Mismatch was recorded if coil primary diameter exceeded or fell below microcatheter thresholds. A generalized linear mixed model accounted for within-patient clustering. Results: Coil failure occurred in 28 of 451 BCCs (6.2 %). A 90–180° inversion at the catheter tip (odds ratio [OR], 22; p = 0.008) and mismatch (OR, 4.9; p = 0.03) independently predicted failure. A proximal 90–180° inversion also contributed (OR, 4.5; p = 0.03). Of 28 failures, 21/28 (75%) were mismatched: 16/21 (76%) resolved via mismatch correction, and 5/21 (24%) required repositioning or an alternate coil gauge/length. Proper-match failures (n=7) were treated with thinner or more flexible coils in 6 (85.7%; p < 0.0001). Conclusions: Sharp vessel angulation (≥90–180°) and microcatheter–coil mismatch each heighten maldelivery risk. Repositioning or adjusting coil dimensions can salvage mismatched cases, whereas more flexible coils help in matched cases.