Transient Elastography in Primary Sclerosing Cholangitis—the Value as a Prognostic Factor and Limitations

Abstract

We read with interest the recent work by Corpechot et al1Corpechot C. et al.Gastroenterology. 2014; 146: 970-979Abstract Full Text Full Text PDF PubMed Scopus (192) Google Scholar describing the diagnostic and prognostic value of transient elastography (TE) for patients with primary sclerosing cholangitis (PSC). We congratulate the authors for this important work; the establishment of TE as a noninvasive marker of risk assessment in PSC is a valuable tool for clinicians as well as researchers aiming to design clinical trials. As suggested in the accompanying editorial by Vuppalanchi and Lindor,2Vuppalanchi R. et al.Gastroenterology. 2014; 146: 890-892Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar these findings need to be confirmed by independent studies and our own findings are supportive (data not shown). TE has been established as a prognostic tool for other chronic liver diseases. There are several confounding factors that may influence liver stiffness. With respect to PSC and the work presented by Carpechot et al, there is an important limitation that we would like to underline. In our cohort of patients, approximately 25% of patients have abnormal serum bilirubin levels at the time of the first evaluation (approximately 5% of patients had levels >2.5 mg/dL). These patients often present with dominant strictures of the common or main hepatic ducts. As exemplified by one of our patients, the presence of biliary strictures may significantly influence liver stiffness in PSC: When the patient was first evaluated for liver stiffness, the result of the measurement was 43.8 kPa. At this time point, he had a serum bilirubin of 8.7 mg/dL and suffered from a dominant stricture of the common bile duct. After biliary endoscopy with dilatation and stenting of the stenosis, the TE value measured 4 weeks later had decreased to 11.6 kPa (serum bilirubin was 1.0 mg/dL then). Another 6 weeks later, his TE measurement was 9.2 kPa and the serum bilirubin was 0.5 mg/dL. This decline in liver stiffness after sufficient biliary drainage is in accord with findings in other cholestatic diseases3Millonig G. et al.Hepatology. 2008; 48: 1718-1723Crossref PubMed Scopus (486) Google Scholar and indicates that liver stiffness can be significantly influenced by biliary obstruction and stasis in PSC. Patients with dominant strictures were excluded in the study by Corpechot et al. We would like to underline that hepatic imaging must be performed before TE measurement in patients with PSC to correctly interpret the results obtained. Baseline Values and Changes in Liver Stiffness Measured by Transient Elastography Are Associated With Severity of Fibrosis and Outcomes of Patients With Primary Sclerosing CholangitisGastroenterologyVol. 146Issue 4PreviewPrimary sclerosing cholangitis (PSC) is a chronic cholestatic disease that leads to extensive liver fibrosis and cirrhosis, which are associated with poor outcome. However, there are no validated noninvasive markers of liver fibrosis in patients with PSC. We assessed the diagnostic performance, reproducibility, longitudinal changes, and prognostic value of liver stiffness measurement (LSM) using vibration-controlled transient elastography (VCTE). Full-Text PDF ReplyGastroenterologyVol. 147Issue 2PreviewWe thank our German colleagues for their judicious comments and are pleased to note that they obtained similar findings in their own patient population, thus confirming in an independent cohort the usefulness of liver stiffness measurement (LSM) as assessed by transient elastography as a noninvasive marker of risk assessment in primary sclerosing cholangitis. Ehlken et al point out an important issue, highlighting the fact that transient elastography results should always be interpreted within a given clinical, biochemical, and radiologic context, taking into account all factors (food intake, weight change, acute hepatitis, acute cholangitis, right heart failure, etc) capable of altering liver stiffness transiently. Full-Text PDF