Relationship Between Spleen Pathologic Changes and Spleen Stiffness in Portal Hypertension Rat Model

Abstract

The aim of the study described here was to explore the influence of splenic pathology and hemodynamic parameters on spleen stiffness in portal hypertension (PH). A Sprague‒Dawley rat model of PH (n=34) induced by CCl4 was established, and 9 normal rats were used as controls. All animals underwent a routine ultrasound examination, spleen stiffness measurement (SSM), liver stiffness measurement (LSM), portal vein pressure (PVP) measurement and histopathologic assessment. The diagnostic performance of SSM and LSM in PH was evaluated. SSMs were compared among the groups at different pathologic and hemodynamic levels. Multiple linear regression was used to analyze the factors affecting SSM. SSM had excellent diagnostic efficacy for PH (area under the receiver operating characteristic curve [AUC]=0.900) and was superior to LSM (AUC=0.794). In a rat model of PH, pathologic changes such as splenic sinus widening, thickening of the splenic capsule and an increase in collagen fibers were observed in the spleen. There were significant differences in SSM at different splenic capsule thicknesses and splenic sinus widths (all p values <0.05), but there were no significant differences in the SSM at different levels of the splenic collagen fiber area and red pulp area (all p values >0.05). In addition, there were significant differences in SSM at different levels of portal vein diameter, blood flow and congestion index (all p values <0.05). Multiple linear regression analysis revealed that PVP, portal vein congestion index and splenic capsule thickness were significantly associated with SSM. SSM is a good non-invasive way to assess PH. PVP, splenic capsule thickness and portal vein congestion index are responsible for spleen stiffness but not the proliferation of splenic fibrous tissue.