Usefulness of Controlled Attenuation Parameter and Liver Stiffness Measurement for the Identification of Extended-criteria Donors and Risk-assessment in Liver Transplantation

Abstract

Background: Controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) are noninvasive surrogates for hepatic steatosis and fibrosis, respectively, and could help identify extended criteria donors in liver transplantation (LT). We aimed to determine the accuracy of CAP/LSM in deceased donors along with post-LT changes.

Methods: Accuracy of preprocurement CAP/LSM to grade/stage steatosis/fibrosis was determined using liver biopsy as reference. Transplant outcomes, including primary nonfunction (PNF) and early allograft dysfunction, were recorded. Recipients underwent CAP/LSM as outpatients. Areas under the receiver operating characteristic curve and regression models were constructed to analyze data.

Results: We prospectively evaluated 160 allografts (138 transplanted). Same-probe paired baseline/post-LT CAP was 231 dB/m (181-277)/225 (187-261) (P = 0.61), and LSM 7.6 kPa (6.3-10.8)/5.9 (4.6-8.7) (P = 0.002), respectively. CAP reading was affected by BMI and LSM by ALT, race and bilirubin. Although CAP did not correlate with steatosis from frozen sections (ρ = 0.08, P = 0.47), it correlated with steatosis from permanent sections (ρ = 0.32, P < 0.001) and with oil red O histomorphometry (ρ = 0.35, P = 0.001). CAP identified moderate-to-severe steatosis with an areas under the receiver operating characteristic curve curve of 0.79 (0.66-0.91), for a negative predictive value of 100% at a cutoff value of 230 dB/m. LSM correlated with fibrosis staging (ρ = 0.22, P = 0.007) and it identified discarded allografts with advanced fibrosis/cirrhosis. Patients with no to minimal fibrosis had an LSM of 7.6 (6-10.1) kPa.

Conclusions: Our results are proof-of-concept of the utility of CAP/LSM during organ procurement. Establishing the precise role of these noninvasive tools in the organ allocation process mandates confirmatory studies.