Incidence and Predictors of Hemorrhagic Conversion After Mechanical Thrombectomy, Experience from a Large...

Hemorrhagic conversion (HC) remains one of the most feared complications after mechanical thrombectomy (MT) for acute ischemic stroke and is associated with poor clinical outcomes. Evidence regarding predictors of HC after MT remains inconsistent. We sought to determine the incidence, predictors, and clinical impact of HC in a large contemporary cohort.

We conducted a retrospective analysis of a prospectively maintained database including consecutive patients who underwent MT for acute ischemic stroke between January 2016 and December 2024. Baseline clinical, radiographical, and procedural variables were collected. Outcomes were compared between patients with and without HC using 1:1 propensity score matching. Multivariable logistic regression was performed to identify independent predictors of HC.

Among 896 patients undergoing MT, 267 (29.8%) experienced HC. After propensity score matching, HC remained associated with worse discharge neurological status (National Institutes of Health Stroke Scale 12.7 vs 9.6; P = .013), longer hospital length of stay (12.3 vs 9.9 days; P = .004), higher rates of decompressive craniectomy (9.4% vs 2.2%; P < .001), and increased likelihood of nonhome discharge (83% vs 71%; P < .001). In-hospital mortality was not significantly different after matching. On multivariable analysis, independent predictors of HC included higher admission National Institutes of Health Stroke Scale score (odds ratio [OR]: 1.04), diabetes mellitus (OR: 2.08), chronic kidney disease (OR: 1.76), and ≥3 thrombectomy passes (OR: 1.75). Increasing age (OR: 0.98), Black race (OR: 0.61), stent-retriever alone thrombectomy (OR: 0.53), and posterior circulation strokes (OR: 0.27) were all significantly associated with lower odds of HC.

HC occurs in approximately one-third of patients undergoing MT and is independently associated with substantial neurological morbidity and healthcare utilization. Stroke severity, metabolic comorbidities, stroke location, and procedural complexity are key determinants of hemorrhagic risk. These findings support the need for enhanced risk stratification, and heightened postprocedural vigilance in high-risk patients.