Spleen stiffness (SS) might reflect portal pressure better than liver stiffness (LS). In fact, the severity of portal hypertension (PH) depends also on the increase in porto-systemic flow that cannot be measured by LS. PH leads to spleen congestion that increases the stiffness of the organ; moreover, experimental data have shown that it induces splenic fibrosis.
The repeatability of SS measurements has been assessed in healthy subjects, and it has been shown that the intra-observer and inter-observer agreement is higher for the liver than for the spleen, and that there is an improved repeatability of SS measurements at all sites with training. Also in patients with clinically significant portal hypertension (CSPH) LS was more feasible than SS. In these patients, both LS and SS correlate with HVPG. SS can predict clinical complications in compensated cirrhosis It has been reported that, in these patients, SS has a high discriminative ability for predicting oesophageal variceal bleeding than LS, with AUROCs of 0.86 for SS and 0.67 for LS. An algorithm to rule out CSPH combining shear-wave elastography of liver and spleen, has been proposed.
The Baveno VI consensus in PH suggests that patients with a liver stiffness <20 kPa and with a platelet count >150,000 have a very low risk of having varices requiring treatment, and can avoid screening endoscopy. It has been shown that combining SS measurement with the Baveno VI criteria a higher number of screening endoscopy may be avoided. LS and SS measurements may stratify the risk of variceal bleeding in cirrhotic patients, and it has been suggested that patients with cirrhosis may first have LS and SS measurement to save up half of the upper endoscopy examinations.
It has been reported that successful antiviral treatment of chronic hepatitis C leads to a rapid decline of LS without an early effect on SS. The rapid effect of treatment on LS doesn't have an immediate effect on PH represented by an unchanged SS; thus, the risk of variceal hemorrhage in the short term is not decreased. It has been shown that, in patients with liver cirrhosis, measurement of SS predicts mortality and hepatic decompensation with greater accuracy than other parameters. Despite all these promising results, in the update on liver elastography guidelines of the WFUMB it has been suggested that further studies are needed before including SS in the diagnostic work-up of cirrhotic patients.