Formula to predict platelet count after partial splenic arterial embolization in patients with hypersplenism.

Purpose To establish a formula to guide appropriate embolization volume for postprocedural platelet gain following partial splenic arterial embolization (PSE) for hypersplenism. Materials and Methods The hepatic volume (Vh) and splenic volume (Vsp) were measured by using 2-mm-thick computed tomography images before and after PSE in 20 patients with various chronic liver diseases. A formula was derived from the relationship between the platelet count increase ratio (dPlt%) and the organ volumes, which was then evaluated in another cohort. Results After an embolization of a median of 72.1% of the spleen (interquartile range, 38.2%–93.8%), the dPlt% was 67.7% ± 40.0 and significantly correlated with the increasing ratio of Vh to Vsp ( P = .019, ρ = 0.52). Because the difference in Vh/Vsp ratio after PSE was significantly correlated with the spleen embolization ratio (eVsp%; P = .0003, ρ = 0.72), the estimated dPlt% could be derived from the Vh/Vsp ratio before PSE and the eVsp%. The estimated dPlt% was significantly correlated with the actual dPlt% ( P = .0003, ρ = 0.72). When the formula was evaluated in another cohort of 14 cases, another strict correlation was observed ( P Conclusions These data suggest that platelet count after PSE can be predicted before the procedure by using the Vh/Vsp ratio and the anticipated spleen embolization volume. The use of such a prediction can prevent too much or too little embolization, thereby leading to an improvement in the risk/return trade-off in PSE.