Mechanical Thrombectomies Requiring an Increased Number of Passes are Associated with Unfavorable Angiographic Outcomes

Mechanical thrombectomy is the standard treatment for acute ischemic stroke due to large-vessel occlusion, but the impact of multiple retrieval attempts on angiographic success and procedural safety remains uncertain.To evaluate the association between the number of thrombectomy passes and the likelihood of unsuccessful reperfusion and procedural complications.We analyzed a prospective registry of 291 consecutive patients who underwent mechanical thrombectomy at a tertiary center between 2020 and 2025. The variables collected included clinical, radiological, and procedural data. Unfavorable angiographic outcome was defined as a modified Treatment in Cerebral Ischemia (mTICI) score ≤ 2a. Logistic regressions were used to evaluate the predictors of unfavorable reperfusion and complications.The mean number of retrieval attempts was of 2.6 ± 1.9. Each additional attempt was associated with a 37% increase in the odds of an unfavorable angiographic outcome (odds ratio OR =1.37; 95%CI: 1.18-1.60). Patients requiring ≥ 3 passes presented significantly higher odds of angiographic failure (OR = 2.85; 95%CI: 1.55-5.42) and significantly higher complication rates (OR = 1.98; 95%CI: 1.01-4.03). Complications occurred in 15.2% of the cases, including dissections (5.2%), distal embolization (6.3%), and arterial rupture (2.2%). The rate of favorable mTICI score (≥2b) progressively declined from 76.7% in the first pass to 17.6% for patients with ≥ 6 passes.Thrombectomy cases requiring passes are strongly associated with a higher risk of angiographic failure and procedural complications. Further studies are necessary to explore the mechanisms behind this association.