Shear Wave Elastography as a Quantitative Biomarker of Clinically Significant Portal Hypertension: A Systematic Review and Meta-Analysis

OBJECTIVE. To qualify shear wave elastography (SWE) as a biomarker for clinically significant portal hypertension (CSPH) beyond proof of concept, we aimed to accumulate and summarize the current evidence through systematic review and meta-analysis. MATERIALS AND METHODS. A computerized literature search was performed to identify studies from MEDLINE and EMBASE up to February 9, 2017. Studies on the diagnostic performance of liver stiffness measurements using SWE for CSPH with hepatic venous pressure gradient (HVPG) as the reference standard were included. Various aspects of SWE were comprehensively assessed. The summary diagnostic performance of SWE for the diagnosis of CSPH and the summary correlation coefficient between liver stiffness measured using SWE and HVPG were evaluated through a meta-analysis. RESULTS. Nine articles (including 746 patients) were retrieved. The diagnostic performance of SWE for the diagnosis of CSPH was fairly good, with a summary sensitivity of 85% (95% CI, 75-91%; I-2 = 78.56%) and summary specificity of 85% (95% CI, 77-90%; I-2 = 0%); the area under the ROC curve was 0.88 (95% CI, 0.85-0.91). The summary correlation coefficient between liver stiffness and HVPG measurements was 0.741 (95% CI, 0.658-0.825; I-2 = 0%). These results support the value of SWE as a diagnostic biomarker for CSPH. However, there was significant heterogeneity in the imaging devices, protocols, liver stiffness measurement methods, and cutoff values used, which suggests that standardization is required. CONCLUSION. The consistent evidence favoring SWE as a biomarker for CSPH should be considered in the biomarker qualification process and management of patients with CSPH.