Diagnostic performance of liver stiffness as marker of liver involvement in systemic immunoglobulin light chain (AL) amyloidosis.

Abstract

To investigate the diagnostic performance of liver stiffness for detecting liver involvement in immunoglobulin light chain (AL) amyloidosis. Liver stiffness was measured using transient elastography in 71 patients with systemic AL amyloidosis and 18 patients with wild type transthyretin (ATTRwt) amyloidosis with cardiomyopathy. Both non-invasive consensus criteria and serum amyloid P component (SAP) scintigraphy were used as substitute standards instead of liver biopsy for establishing liver involvement. Liver stiffness was higher in AL amyloidosis patients with liver involvement than in those without: this was observed using both consensus criteria (median 14.4kPa vs. 8.1kPa; p = 0.001) and SAP scintigraphy (median 20.9kPa vs. 6.2kPa; p < 0.001). Liver stiffness was also higher in AL amyloidosis patients with liver involvement compared to AL and ATTRwt amyloidosis patients with cardiac involvement. Based on receiver operating characteristic (ROC) curves a cut-off value of 14.4kPa for stiffness was optimal to indicate liver involvement, providing sensitivity and specificity of 50% and 74%, respectively, using the consensus criteria and 63% and 90%, respectively, using SAP scintigraphy as standard. Liver stiffness is a promising tool to establish liver involvement in AL amyloidosis having potential to become part of updated criteria for liver involvement.