Spleen Stiffness Probability Index (SSPI): A simple and accurate method to detect esophageal varices in patients with compensated liver cirrhosis.

INTRODUCTION AND OBJECTIVES: Recent findings pointed out that even low-risk esophageal varices (EVs) are markers of severe prognosis. Accordingly, we analyzed spleen stiffness (SS) as a non-invasive method to predict EVs of any grade in a cohort of patients with compensated liver cirrhosis. METHOD: We measured SS and liver stiffness (LS) using point-Shear-Wave Elastography (pSWE) with Philips Affiniti 70 system in 210 cirrhotic patients who had undergone endoscopic screening for EVs. We compared SS and LS predictive capability for EVs of any grade. RESULTS: SS was higher in cirrhotic patients with EVs if compared to patients without EVs (p<0.001). The cut-off analysis detected 31kPa (100% sensitivity and negative predictive value) as the value to rule-out EVs and 69kPa (100% specificity and positive predictive value) to rule-in EVs. Besides, we developed the Spleen Stiffness Probability Index (SSPI), that can provide a probability of presence/absence of EVs. SSPI was the best model according to all discriminative and calibration metrics (AIC=120, BIC=127, AUROC=0.95, Pseudo-R2=0.74). SS demonstrated higher correlation with spleen bipolar diameter and spleen surface (r=0.52/0.55) if compared to LS (r=0.30/0.25) - and with platelet count as well (r=0.67 vs r=0.4). CONCLUSION: SS showed significantly higher performance than other parameters, proving to be the best non-invasive test in the screening of EVs: by directly applying SS cut-off of 31kPa, our department could have safely avoided endoscopy in 36% of patients. Despite cut-off analyses, it was possible to create a probability model that could further stratify low-risk from high-risk patients (for any grade of EVs).

Evaluation of spleen stiffness in healthy volunteers using point shear wave elastography.

INTRODUCTION AND OBJECTIVES: This study aims to measure the values of spleen stiffness (SS) in healthy subjects, the inter-operator agreement in SS measurement, and to detect statistically significant correlations between SS and age, sex, weight, BMI, portal vein dynamics and splenic dimensions. MATERIALS AND METHODS: The study included 100 healthy volunteers who had no substantial alcohol intake (<30g/daily for man, <20g/daily women), were negative on hepatitis B, hepatitis C, HIV blood serology, and had any history of lymphoproliferative disorders. Abdominal ultrasound, liver and spleen elastography were performed on each patient to search for focal splenic lesions, bile tract or portal vein dilatation, moderate/severe liver steatosis, and to measure liver and spleen stiffness. RESULTS: The mean value was 18.14 (±3.08) kPa. In the group of men (n=49), the mean was 17.73 (±2.91) kPa, whereas in the group of women (n=51) it was 16.72 (±3.32) kPa. Statistical analyses showed no correlation between spleen stiffness and sex, age, weight, and BMI. Regarding their splenoportal axis, statistically significant differences in SS were found in the means of the two subgroups of subjects stratified by their portal flow velocity (p=0.003) and spleen area (p<0.001). Spearman's rank showed a weak association between SS and portal flow velocty (r=0.271) and splenic area (r=-0.237). ICC showed excellent (0.96) inter-operator agreement and Bland-Altman plot demonstrated no systematic over/under-estimation of spleen stiffness values. CONCLUSIONS: Our results may serve as a reference point in the evaluation of SS especially in patients affected by advanced liver disease.