Partial splenic embolization with embosphere microspheres (700-900 µm) for the treatment of hypersplenism: comparison of selective superior splenic artery embolization and inferior splenic artery embolization.

Objective: To compare clinical outcomes of superior versus inferior splenic artery embolization in partial splenic embolization (PSE) and identify predictors of major complications. Material and methods: This retrospective case-control study included 73 patients who underwent PSE between May 2005 and April 2021. They were divided into two groups: the superior and middle splenic artery embolization group (Group A, n  = 37) and the inferior and middle splenic artery embolization group (Group B, n  = 36). Outcome differences and major complications between the groups were assessed. Logistic regression was used to analyze potential predictors of major complications, and the optimal cutoff value for splenic embolization rates was determined using the Youden index. Results: There were no significant differences in laboratory and radiological outcomes between the two groups. Group A had a significantly lower incidence of major complications than Group B ( p  = 0.049), a lower Visual Analog Scale (VAS) score for pain ( p  = 0.036), and a shorter hospital stay ( p  = 0.022). Independent risk factors for major complications included inferior and middle splenic artery embolization (odds ratio [OR] = 3.672; 95% confidence interval [CI] = 1.028-13.120; p  = 0.045) and a higher spleen embolization rate (OR = 1.108; 95% CI = 1.003-1.224; p  = 0.044). The optimal cutoff for spleen embolization rate to predict major complications was 59.93% (sensitivity 77.8%, specificity 63.6%). Conclusion: Using 500-700 µm microspheres for PSE, targeting the middle and superior splenic artery yields similar effects to targeting the middle and inferior artery, but results in lower rates of major complications and shorter hospital stays. To effectively minimize the risk of major complications, the embolization rate should be kept below 59.93%, regardless of the target vessel.