Practical Tortuosity Index Is Associated with Complete Recanalization in Distal M2 Thrombectomy: The D-MOTIVE Study

PURPOSE: Mechanical thrombectomy for distal medium-vessel occlusions has not shown superiority over best medical treatment. Patient selection remains an important unresolved challenge, and anatomical factors associated with procedural success are underexplored. This study evaluated whether simple CTA–derived metrics are associated with recanalization and clinical outcomes in distal M2 occlusions. MATERIALS AND METHODS: D-MOTIVE was a retrospective cohort study including consecutive patients treated with mechanical thrombectomy for distal M2 occlusion between January 2023 and December 2024, defined according to DISCOUNT trial criteria. Baseline CTA scans were analyzed using routine multiplanar reconstructions without dedicated post-processing software. Anatomical metrics—including tortuosity index measured in three orthogonal planes and the presence of acute vessel angulations—were assessed independently by two blinded readers. Receiver operating characteristic analyses were used to explore the discriminative performance of anatomical metrics for complete recanalization and 90-day mRS ≤2, and Youden-derived cutoffs were applied for exploratory dichotomization. The primary efficacy outcome was complete recanalization (mTICI 3). The primary safety outcome was symptomatic intracranial hemorrhage. Interobserver agreement was assessed for sagittal M2 tortuosity. RESULTS: Among 262 patients with M2 occlusion, 51 met inclusion criteria (median age 72 years; 53% male). High sagittal M2 tortuosity (data-driven tortuosity index ≥ 1.19) was associated with lower rates of complete recanalization (39% vs 70%), reduced first-pass effect (11.1% vs 38.9%), and fewer patients achieving functional independence (mRS 0–2) at 90 days (16.7% vs 72.7%). After adjustment, high sagittal tortuosity remained associated with lower odds of complete recanalization (adjusted OR, 0.18; 95% CI, 0.04–0.74; p=0.02), more device passes (median increase of 1.0; 95% CI 0.05–1.95; p=0.04), and lower odds of favorable functional outcome at 90 days (mRS ≤2) (adjusted OR, 0.11; 95% CI, 0.02–0.53; p=0.007). Hemorrhagic and procedural complications were similar between groups. CONCLUSIONS: Higher sagittal M2 tortuosity index was associated with a lower likelihood of complete recanalization and worse 90-day outcomes in distal M2 thrombectomy. These exploratory findings, requiring external validation, suggest that simple CTA–based anatomical markers, readily accessible in routine clinical practice, may help to identify patients less likely to achieve favorable outcomes with thrombectomy in distal medium-vessel occlusions.