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

To establish a formula to guide appropriate embolization volume for postprocedural platelet gain following partial splenic arterial embolization (PSE) for hypersplenism.

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.

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 < .0001, ρ = 0.92).

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.