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To the Editor:

With great interest, we read the study by Arena et al.[1] showing an increase in liver stiffness 15 to 45 minutes after the intake of a standardized liquid meal lowering the accuracy of fibrosis assessment by transient elastography (TE). These results are in line with another study using liquid meals[2] and our previous findings obtained under “real-life” conditions using standardized solid meals.[3] Similarly, liver stiffness as assessed by acoustic radiation force impulse (ARFI) elastography is influenced by food intake.[4]

In patients with cirrhosis, Berzigotti et al.[2] showed that increased hepatic arterial but not portal blood flow is responsible for the increase of liver stiffness after food intake.

Unfortunately, the initial studies on liver stiffness determination using TE did not explicitly pay regard to currently known confounding factors (Table 1). TE appeared to be reasonably accurate to distinguish cirrhosis from precirrhotic stages, and severe fibrosis from early fibrosis.[5] However, early fibrosis stages exhibited considerable overlap in liver stiffness measurement. Final assessment was hampered by the limitations of liver biopsy as the reference method.[6] Although knowledge of confounding factors of TE might raise speculations that “optimized” TE could even outperform histology, we should not forget that liver stiffness indicates hepatic collagen content rather than a histological picture and that there is significant overlap of hepatic collagen content in the different stages of fibrosis.[7, 8] Thus, taking hepatic collagen content instead of histologically defined stages might improve revelation of the full performance of TE if measurement is performed under standardized conditions with accepted reliability criteria.[9] However, the ultimate test will be the prediction of clinically relevant endpoints.

Table 1. Factors Influencing Accuracy of Transient Elastography
Cholestasis
Elevated ALT
Central venous pressure
Food intake
Respiratory cycle
Hepatic congestion
Cardiac insufficiency
  • Ingmar Mederacke, M.D.1

  • Matthias J. Bahr, M.D.2

  • 1Hannover Medical School

  • Gastroenterology, Hepatology and Endocrinology

  • Hannover, Germany

  • 2Sana Kliniken Luebeck

  • Luebeck, Germany

References

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