Performance of Controlled Attenuation Parameter in Patients with Advanced Chronic Liver Disease and Portal Hypertension

Ultrasound-Based Diagnostic Methods: Possible Use in Fatty Liver Disease Area

Liver steatosis is a chronic liver disease that is becoming one of the most important global health problems, due to its direct connection with metabolic syndrome, its significant impact on patients' socioeconomic status and frailty, and the occurrence of advanced chronic liver disease. In recent years, there has been rapid technological progress in the ultrasound-based diagnostics field that can help us to quantitatively assess liver steatosis, including continuous attenuation parameters in A and B ultrasound modes, backscatter coefficients (e.g., speed of sound) and ultrasound envelope statistic parametric imaging. The methods used in this field are widely available, have favorable time and financial profiles, and are well accepted by patients. Less is known about their reliability in defining the presence and degree of liver steatosis. Numerous study reports have shown the methods' favorable negative and positive predictive values in comparison with reference investigations (liver biopsy and MRI). Important research has also evaluated the role of these methods in diagnosing and monitoring non-alcoholic fatty liver disease (NAFLD). Since NAFLD is becoming the dominant global cause of liver cirrhosis, and due to the close but complex interplay of liver steatosis with the coexistence of liver fibrosis, knowledge regarding NAFLD's influence on the progression of liver fibrosis is of crucial importance. Study findings, therefore, indicate the possibility of using these same diagnostic methods to evaluate the impact of NAFLD on the patient's liver fibrosis progression risk, metabolic risk factors, cardiovascular complications, and the occurrence of hepatocellular carcinoma. The mentioned areas are particularly important in light of the fact that most of the known chronic liver disease etiologies are increasingly intertwined with the simultaneous presence of NAFLD.

PNPLA3 is the dominant SNP linked to liver disease severity at time of first referral to a tertiary center

BACKGROUND

Single nucleotide polymorphisms (SNPs) in genes including PNPLA3, TM6SF2, HSD17B13 and SERPINA1 have been identified as risk modifiers of progression in chronic liver disease (CLD). However, it is unclear whether genotyping for these risk variants is useful in clinical routine.

METHODS

Liver disease severity was assessed by liver stiffness measurement (LSM) and by presence of clinical manifestations of advanced-chronic liver disease (ACLD) in 779 consecutive CLD patients at the time of referral to a tertiary center. The associations of risk variants with CLD severity were calculated individually and in a combined model using a polygenic risk-score.

RESULTS

Non-alcoholic fatty liver disease (NAFLD) was the most common etiology (n = 511, 65.6%), and ACLD was present in 217 (27.9%) patients. The PNPLA3-G-allele remained independently associated with higher LSM (adjusted-B: 2.508 [95%CI: 0.887-4.130], P = 0.002) or the presence of ACLD (aOR: 1.562 [95%CI: 1.097-2.226], P = 0.013). SERPINA1-Z-allele was also independently associated with LSM (adjusted-B: 4.558 [95%CI: 1.182-7.934], P = 0.008), while the other risk alleles did not attain statistical significance. Combining these risk alleles into a polygenic risk-score was significantly associated with LSM (adjusted-B: 0.948 [95%CI: 0.153-1.743], P = 0.020).

CONCLUSION

PNPLA3 risk-variants are linked to liver disease severity at the time of first referral to an outpatient hepatology clinic.

Influence of Genetic Variants on Disease Regression and Outcomes in HCV-Related Advanced Chronic Liver Disease after SVR

Genetic variants including PNPLA3-rs738409 C>G, TM6SF2-rs58542926 C>T, MBOAT7-rs641738 C>T, and HSD17B13-rs72613567 T>TA have been shown to influence progression to advanced chronic liver disease (ACLD) in patients with chronic hepatitis C (CHC). We aimed to investigate their impact on disease regression (i.e., changes in hepatic venous pressure gradient [HVPG] and non-invasive surrogates [liver stiffness measurement (LSM), von Willebrand factor (VWF), and VWF/platelet count ratio (VITRO)]) and clinical outcomes after CHC cure in 346 patients with pre-treatment ACLD. Patients carrying the PNPLA3 minor allele had more advanced liver disease prior to antiviral therapy, confirming its impact on liver disease progression. In a subgroup of 88 patients who underwent paired HVPG-measurements and were genotyped for all SNP/indels, PNPLA3/TM6SF2/MBOAT7/HSD17B13 genotypes were not associated with changes in HVPG. In line, changes in non-invasive surrogates of portal hypertension (LSM/VWF/VITRO) were comparable between carriers and non-carriers of the PNPLA3 G-allele in the overall cohort. Finally, carriage of PNPLA3 G-allele was not associated with the development of hepatic decompensation, de-novo hepatocellular carcinoma, or transplant-free mortality during a median follow-up of 42 months after the end of antiviral treatment. Therefore, genetic variants in PNPLA3/TM6SF2/MBOAT7/HSD17B13 do not impact the regression of portal hypertension and clinical outcomes in patients with pre-treatment ACLD after CHC cure.

Noninvasive Markers of Portal Hypertension Detect Decompensation in Overweight or Obese Patients With Compensated Advanced Chronic Liver Disease

BACKGROUND & AIMS

Some patients with compensated advanced chronic liver disease (cACLD) require use of an extralarge probe for liver stiffness measurement (LSM), owing to overweight or obesity. However, the ability of noninvasive markers of portal hypertension and the controlled attenuation parameter (CAP) to determine which of these patients are at risk for decompensation has not been fully assessed.

METHODS

We collected data from 272 patients with cACLD (LSM ≥10 kPa by XL probe; 57% with nonalcoholic steatohepatitis; mean body mass index, 33.8 ± 6.5 kg/m²; median Child-Pugh score, 5; median LSM, 16.8 kPa; mean CAP, 318 ± 66 dB/m) evaluated at 2 academic centers from 2015 through 2018. We collected clinical data on decompensation (ascites, portal hypertension bleeding, jaundice, hepatic encephalopathy) and severe bacterial infections; patients were followed up for a median of 17 months (interquartile range, 11-24 mo). We evaluated associations between these events and LSM, CAP, LSM∗spleen size/platelet count (LSPS), and portal hypertension risk scores.

RESULTS

Decompensation occurred in 12 patients and severe bacterial infections developed in 5 patients. LSM, LSPS, and the portal hypertension risk score identified patients with decompensation with area under the receiver operating characteristic curve values of 0.848 (95% CI, 0.720-0.976; P < .0001), 0.881 (95% CI, 0.798-0.954; P < .0001), and 0.890 (95% CI, 0.814-0.966; P < .0001), respectively. In multivariate Cox regression analysis, in patients with nonalcoholic steatohepatitis, LSM and CAP were associated independently with decompensation and severe bacterial infection; CAP ≥ 220 dB/m was associated with a reduced risk of decompensation (hazard ratio, 0.043, 95% CI, 0.004-0.476; P = .01).

CONCLUSIONS

LSM, LSPS, and the portal hypertension risk score identify obese or overweight patients with cACLD who are at increased risk of decompensation and severe bacterial infection.

Novel reliability criteria for controlled attenuation parameter assessments for non-invasive evaluation of hepatic steatosis

BACKGROUND

There is conflicting evidence regarding reliability criteria for the controlled attenuation parameter (CAP; a marker for hepatic steatosis [HS]). Thus, we assessed the diagnostic performance of CAP according to different reliability criteria based on real-world data from an academic centre.

METHODS

Patients undergoing measurement of CAP and liver biopsy (±6 months) at the Medical University of Vienna were included. HS was assessed according to SAF score.

RESULTS

In total 319 patients were included. The main aetiologies were non-alcoholic fatty liver disease (NAFLD, n = 177, 55.5%), viral hepatitis (n = 49, 15.4%), and alcoholic liver disease (ALD, n = 29, 9.1%). Histological steatosis and fibrosis stages were: S0: 93 (29.2%), S1: 100 (31.3%), S2: 67 (21.0%), and S3: 59 (18.5%); F0/F1: 150 (47.0%), F2: 47 (14.7%), and F3/F4: 122 (48.3%). In the overall cohort, the area under the receiver operating characteristic curve (AUC) of CAP was 0.843 (95% confidence interval [CI]: 0.798-0.887) for diagnosing HS ≥ S1), 0.789 (95%CI: 0.740-0.839) for ≥S2, and 0.767 (95%CI: 0.712-0.823) for S3. CAP corrections as suggested by Karlas et al. did not improve the diagnostic performance. Importantly, the AUC of CAP for HS ≥ S1 was numerically highest in patients with CAP-IQR/median<0.10 or <0.20 (obtained in 37.9% and 74.9%), in whom CAP also had better diagnostic performance, as compared with patients not meeting these criteria. Moreover, it was substantially higher in 288 (90.3%) patients with CAP-IQR/median<0.3: 0.856 (95%CI: 0.809-0.903) vs. patients not meeting this criterion (0.530 [95%CI: 0.309-0.751]). In contrast, the previously suggested reliability criterion of CAP-IQR<40 dB/m was not associated with an improved diagnostic performance for HS≥S1 (0.866 [95%CI: 0.812-0.920] vs. 0.799 [95%CI: 0.717-0.881]) and was only obtained in 199 (62.4%) patients.

CONCLUSION

CAP-IQR/median<0.1, <0.2, and <0.3 identify reliable measurements for diagnosing any hepatic steatosis (≥S1). Importantly, CAP-IQR/median<0.3 has a considerably higher applicability in clinical practice, as compared with the previously suggested CAP-IQR<40 dB/m criterion.

The impact of hepatic steatosis on portal hypertension

Background and aims

Studies in animal models have suggested that hepatic steatosis impacts on portal pressure, potentially by inducing liver sinusoidal endothelial dysfunction and thereby increasing intrahepatic resistance. Thus, we aimed to evaluate the impact of hepatic steatosis on hepatic venous pressure gradient (HVPG) in patients with chronic liver disease.

Method

261 patients undergoing simultaneous HVPG measurements and controlled attenuation parameter (CAP)-based steatosis assessment were included in this retrospective study.

Results

The majority of patients had cirrhosis (n = 205; 78.5%) and n = 191 (73.2%) had clinically significant portal hypertension (CSPH; HVPG≥10mmHg). Hepatic steatosis (S1/2/3; CAP ≥248dB/m) was present in n = 102 (39.1%). Overall, HVPG was comparable between patients with vs. without hepatic steatosis (15.5±7.5 vs. 14.8±7.7mmHg; p = 0.465). Neither in patients with HVPG (<6mmHg; p = 0.371) nor in patients with mild portal hypertension (HVPG 6–9mmHg; p = 0.716) or CSPH (HVPG≥10mmHg; p = 0.311) any correlation between CAP and HVPG was found. Interestingly, in patients with liver fibrosis F2/3, there was a negative correlation between CAP and HVPG (Pearson’s ρ:-0.522; p≤0.001). In multivariate analysis, higher CAP was an independent ‘protective’ factor for the presence of CSPH (odds ratio [OR] per 10dB/m: 0.92, 95% confidence interval [CI]:0.85–1.00; p = 0.045), while liver stiffness was associated with the presence of CSPH (OR per kPa: 1.26, 95%CI: 1.17–1.36; p≤0.001). In 78 patients, in whom liver biopsy was performed, HVPG was neither correlated with percentage of histological steatosis (p = 0.714) nor with histological steatosis grade (p = 0.957).

Conclusion

Hepatic steatosis, as assessed by CAP and liver histology, did not impact on HVPG in our cohort comprising a high proportion of patients with advanced chronic liver disease. However, high CAP values (i.e. pronounced hepatic steatosis) might lead to overestimation of liver fibrosis by ‘artificially’ increasing transient elastography-based liver stiffness measurements.