Impact of controlled attenuation parameter on detecting fibrosis using liver stiffness measurement

BACKGROUND

Liver fibrosis is often accompanied by steatosis, particularly in patients with non-alcoholic fatty liver disease (NAFLD), and its non-invasive characterisation is of utmost importance. Vibration-controlled transient elastography is the non-invasive method of choice; however, recent research suggests that steatosis may influence its diagnostic performance. Controlled Attenuation Parameter (CAP) added to transient elastography enables simultaneous assessment of steatosis and fibrosis.

AIM

To determine how to use CAP in interpreting liver stiffness measurements.

METHODS

This is a secondary analysis of data from an individual patient data meta-analysis on CAP. The main exclusion criteria for the current analysis were unknown aetiology, unreliable elastography measurement and data already used for the same research question. Aetiology-specific liver stiffness measurement cut-offs were determined and used to estimate positive and negative predictive values (PPV/NPV) with logistic regression as functions of CAP.

RESULTS

Two thousand and fifty eight patients fulfilled the inclusion criteria (37% women, 18% NAFLD/NASH, 42% HBV, 40% HCV, 51% significant fibrosis ≥ F2). Youden optimised cut-offs were only sufficient for ruling out cirrhosis (NPV of 98%). With sensitivity and specificity-optimised cut-offs, NPV for ruling out significant fibrosis was moderate (70%) and could be improved slightly through consideration of CAP. PPV for significant fibrosis and cirrhosis were 68% and 55% respectively, despite specificity-optimised cut-offs for cirrhosis.

CONCLUSIONS

Liver stiffness measurement values below aetiology-specific cut-offs are very useful for ruling out cirrhosis, and to a lesser extent for ruling out significant fibrosis. In the case of the latter, Controlled Attenuation Parameter can improve interpretation slightly. Even if cut-offs are very high, liver stiffness measurements are not very reliable for ruling in fibrosis or cirrhosis.

Assessment of spleen stiffness using acoustic radiation force impulse imaging (ARFI): definition of examination standards and impact of breathing maneuvers

PURPOSE

Spleen elastography is a promising method for the characterization of portal hypertension in cirrhotic individuals. However, standardized examination procedures for spleen stiffness measurement have not been defined yet. We analyzed the distribution characteristics of spleen shear-wave velocity (ARFI) and assessed the influence of the respiratory position on spleen stiffness measured by ARFI.

MATERIALS AND METHODS

25 healthy probands and 25 patients with Child A liver cirrhosis were prospectively characterized with conventional ultrasound, transient elastography, liver ARFI, and underwent spleen ARFI in two respiratory positions: breath hold after expiration (exp) and deep inspiration (insp). For each position 20 single measurements were performed. The distribution of spleen ARFI values was analyzed for normality and the appropriate number of measurements for spleen stiffness estimation was investigated.

RESULTS

Spleen ARFI results were normally distributed in > 95 % of cases. Performing 20 instead of 10 single measurements resulted in < 5 % deviation from the mean value after 20 measurements in the majority of cases. Cirrhotic patients had a higher spleen stiffness compared to healthy probands (exp: 3.25 ± 0.58 vs. 2.46 ± 0.35 m/s; p < 0.001). Deep inspiration caused an overall increase in spleen stiffness in both groups: probands 2.46 ± 0.35 m/s (exp) vs. 2.66 ± 0.36 m/s (insp), p = 0.01; cirrhotics 3.25 ± 0.58 m/s (exp) vs. 3.46 ± 0.38 m/s (insp), p = 0.03. However, cases with high spleen stiffness values (exp) show decreasing ARFI values in deep inspiration.

CONCLUSION

ARFI values of the spleen are normally distributed and the mean of 10 valid measurements can be used as a representative value. Deep inspiration significantly modulates spleen stiffness. Therefore, the respiratory position needs careful standardization.

Prevention of lamivudine-resistant hepatitis B recurrence after liver transplantation with entecavir plus tenofovir combination therapy and perioperative hepatitis B immunoglobulin only

Combination therapy with antivirals plus hepatitis B immunoglobulin (HBIg) has become the standard treatment for prevention of post-liver transplant hepatitis B virus (HBV) recurrence. However, HBIg therapy is inconvenient and expensive. Alternative therapeutic approaches with modern nucleos(t)ide analogues are limited so far. The present case report describes prevention of HBV recurrence with entecavir and tenofovir. A 48-year-old male patient with hepatitis B-induced decompensated liver cirrhosis initially improved on lamivudine (LAM) until LAM resistance (rtL180M and rtM204V) emerged followed by renewed decompensation. Therefore, tenofovir was added to LAM leading to undetectable HBV DNA (<200 copies/mL). Six months later, low-level viremia (479 copies/mL) was detected. Treatment was escalated to tenofovir plus entecavir. HBV DNA became negative again, and the patient underwent orthotopic liver transplantation. HBIg was administered during transplantation (10,000 IU) and on the second and third postoperative days (total dose 26,000 IU). Subsequently, the anti-hepatitis B surface (HBs) titer rose to 1477 IU/L at day 4 post transplantation. Although HBIg should have been continued, the patient remained on combination therapy with tenofovir plus entecavir only. The anti-HBs titer decreased and became negative 4 months later. However, under continued combination therapy with oral antivirals, HBV DNA and hepatitis B surface antigen remained negative during the entire follow-up of 21 months after liver transplantation. Combination therapy with entecavir plus tenofovir may prevent post-liver transplant hepatitis B recurrence even without HBIg maintenance therapy. This case illustrates that combination oral antiviral therapy might substitute for HBIg as indefinite prophylactic regimen due to profound antiviral efficacy and low risk of viral resistance. Efficacy and safety must be further investigated in randomized controlled trials.