Quantitative magnetic resonance imaging in evaluating haemodynamic changes in portal hypertension

The majority of complications in patients with cirrhosis result from the development and progression of portal hypertension characterised by increased intrahepatic resistance and progressive splanchnic vasodilation. Hepatic venous pressure gradient (HVPG) measurement is the only validated technique to accurately evaluate changes in portal pressure. However, HVPG measurements are invasive and available only in specialised hepatology units, precluding its use in routine clinical practice. In the first study, we evaluated the use of non-contrast quantitative magnetic resonance imaging (MRI) as a surrogate measure of portal pressure. 30 patients undergoing HVPG measurement were prospectively recruited. MR parameters of longitudinal relaxation time (T1), perfusion of the liver and spleen (by arterial spin labelling), and blood flow in the portal, splanchnic and collateral circulation (by phase-contrast MRI) were assessed. We estimated the liver stiffness measurement (LSM) and Enhanced Liver Fibrosis (ELF) score. The correlation of all non-invasive parameters with HVPG was evaluated. The mean (range) HVPG of the patients was 9.8 (1-22) mmHg, and 14 patients (48%) had clinically significant portal hypertension (CSPH, HVPG ≥10 mmHg). Liver T1 relaxation time, splenic artery and superior mesenteric artery velocity correlated significantly with HVPG. Using multiple linear regression, liver T1 and splenic artery velocity remained as the two parameters in the multivariate model significantly associated with HVPG (R=0.90, p<0.001). This correlation was maintained in patients with CSPH (R=0.85, p<0.001). A validation cohort (n=10) showed this linear model provided a good prediction of HVPG. LSM and ELF score correlated significantly with HVPG in the whole population but the correlation was absent in CSPH. In conclusion, MR parameters related to both hepatic architecture and splanchnic haemodynamics correlate significantly with HVPG. This proposed model, confirmed in a validation cohort, could replace the invasive HVPG measurement. In the second part, we studied the use non-invasive MRI to dynamically assess changes in hepatic and collateral blood flow, liver perfusion and oxygenation in response to ingestion of a test meal (meal challenge), and hyperoxia and hypercapnia (gas challenge). These changes were compared between healthy subjects and patients with compensated cirrhosis (CC). In the meal challenge study, we evaluated the blood flow in the portal vein, hepatic artery and azygos vein, liver perfusion and blood oxygenation (using transverse relaxation time (T2*) mapping). Measures were collected at baseline and at 6-7 minute intervals from 20 to 65 minutes following a test meal (440 ml; 660 kcal) in 10 healthy participants and 10 CC patients. In healthy participants, we observed a postprandial increase in portal vein flow from baseline coupled with a reduction in hepatic artery flow from baseline, reflecting the hepatic artery buffer response (HABR). In CC patients, changes in portal vein and hepatic artery flow were smaller, with no clear HABR. In healthy participants, postprandial liver perfusion increased, but not in CC patients. There was no change in liver T2* for either group. In the gas challenge study, we evaluated the blood flow in portal vein and hepatic artery, liver perfusion and liver T2* during hyperoxia and hypercapnia in 10 healthy subjects and 4 patients with compensated cirrhosis. A sequential gas delivery breathing circuit and a prospective, feed-forward gas delivery system (Respiract™, Thornhill Research Inc., Toronto, Canada) was used to control and monitor end-tidal O2 (PETO2) and CO2 (PETCO2) partial pressures. Hyperoxia was targeted at PETO2 ~500mmHg and hypercapnia was aimed at PETCO2 ~6mmHg above resting value. The study design consisted of 5 blocks. Blocks 1, 3 and 5 were 5 min periods at resting PETCO2 and PETO2. Blocks 2 and 4 were, in a random order, 5 mins of hyperoxia (with a 2 min transition up and down) or 5 mins of hypercapnia. We observed an increase in portal vein velocity during hypercapnia among the healthy subjects and patients with cirrhosis. There was no significant changes in liver T2* but the full-width-half-maximum (FWHM) of the distribution of the liver T2* increased in response to hyperoxia and hypercapnia in both groups. Subjects with low T2* at baseline exhibited a smaller change in FWHM following the gas challenge. The within session and inter-session coefficient of variation (CoV) the blood flow measurement using phase-contrast MRI in healthy subjects was less than 15%. If our findings are confirmed in external validation studies, non-invasive MRI can be used as a surrogate measure of HVPG. Assessment of postprandial dynamic changes in hepatic, splanchnic and collateral circulation using MRI could potentially be used to stratify patients with portal hypertension and study the effects of potential novel treatments for portal hypertension

MRI assessment of altered dynamic changes in liver haemodynamics following a meal challenge in compensated cirrhosis

Background: To use magnetic resonance imaging (MRI) to dynamically assess postprandial changes in hepatic and collateral blood flow, liver perfusion and oxygenation in healthy participants and patients with liver disease with compensated cirrhosis (CC).Methods: We evaluated blood flow in the portal vein, hepatic artery, and azygos vein (using phase-contrast MRI), liver perfusion (using arterial spin labelling) and blood oxygenation (using transverse relaxation time [T2*] mapping). Measures were collected at baseline and at 6-7 min intervals from 20 to 65 min following a test meal (440 ml; 660 kcal) in 10 healthy participants and 10 CC patients.Results: In healthy participants, we observed a significant postprandial increase in portal vein flow from baseline (+137 ± 26% [mean ± standard deviation], p < 0.001) coupled with a reduction in hepatic artery flow from baseline (-30 ±18%, p = 0.008), reflecting the hepatic artery buffer response. In CC patients, a lower but still significant increase in portal vein (67 ±50 %, p = 0.014) was observed, without a clear hepatic artery buffer response. Healthy participants showed a significant increase in postprandial liver perfusion (138 ± 75%, p < 0.001), not observed in CC patients. There was no change in liver T2* for either group. Conclusions: Postprandial changes in liver perfusion, oxygenation, and hepatic and collateral circulation can be measured non-invasively using MRI. Differences between healthy participants and CC patients were shown, which may help stratify liver cirrhosis in patients

Guidelines on the management of ascites in cirrhosis.

The British Society of Gastroenterology in collaboration with British Association for the Study of the Liver has prepared this document. The aim of this guideline is to review and summarise the evidence that guides clinical diagnosis and management of ascites in patients with cirrhosis. Substantial advances have been made in this area since the publication of the last guideline in 2007. These guidelines are based on a comprehensive literature search and comprise systematic reviews in the key areas, including the diagnostic tests, diuretic use, therapeutic paracentesis, use of albumin, transjugular intrahepatic portosystemic stent shunt, spontaneous bacterial peritonitis and beta-blockers in patients with ascites. Where recent systematic reviews and meta-analysis are available, these have been updated with additional studies. In addition, the results of prospective and retrospective studies, evidence obtained from expert committee reports and, in some instances, reports from case series have been included. Where possible, judgement has been made on the quality of information used to generate the guidelines and the specific recommendations have been made according to the 'Grading of Recommendations Assessment, Development and Evaluation (GRADE)' system. These guidelines are intended to inform practising clinicians, and it is expected that these guidelines will be revised in 3 years' time

Non-invasive assessment of portal hypertension using quantitative magnetic resonance imaging

Background & Aims Hepatic venous pressure gradient (HVPG) measurement is currently the only validated technique to accurately evaluate changes in portal pressure. In this study, we evaluate the use of non-contrast quantitative magnetic resonance imaging (MRI) as a surrogate measure of portal pressure. Methods Thirty patients undergoing HVPG measurement were prospectively recruited. MR parameters of longitudinal relaxation time (T1), perfusion of the liver and spleen (by arterial spin labelling), and blood flow in the portal, splanchnic and collateral circulation (by phase contrast MRI) were assessed. We estimated the liver stiffness measurement (LSM) and enhanced liver fibrosis (ELF) score. The correlation of all non-invasive parameters with HVPG was evaluated. Results The mean (range) HVPG of the patients was 9.8 (1–22) mmHg, and 14 patients (48%) had clinically significant portal hypertension (CSPH, HVPG ⩾10 mmHg). Liver T1 relaxation time, splenic artery and superior mesenteric artery velocity correlated significantly with HVPG. Using multiple linear regression, liver T1 and splenic artery velocity remained as the two parameters in the multivariate model significantly associated with HVPG (R = 0.90, p <0.001). This correlation was maintained in patients with CSPH (R = 0.85, p <0.001). A validation cohort (n = 10) showed this linear model provided a good prediction of HVPG. LSM and ELF score correlated significantly with HVPG in the whole population but the correlation was absent in CSPH. Conclusions MR parameters related to both hepatic architecture and splanchnic haemodynamics correlate significantly with HVPG. This proposed model, confirmed in a validation cohort, could replace the invasive HVPG measurement

Long-term outcomes of liver transplant recipients followed up in non-transplant centres: care closer to home

Introduction: Increasing rates of liver transplantation and improved outcomes have led to greater numbers of transplant recipients followed up in non-transplant centres. Our aim was to document long-term clinical outcomes of liver transplant recipients managed in this ‘hub and spoke’ healthcare model.Methods: A retrospective analysis of all adult patients who underwent liver transplantation between 1987 and 2016, with post-transplant follow-up in two non-transplant centres in the UK (Nottingham) and Canada (Ottawa) was performed.Results: The 1-, 5-, 10- and 20-year patient survival rates were 98%, 95%, 87% and 62%, and 100%, 96%, 88% and 62% in the Nottingham and Ottawa groups, respectively (p=0.87). There were no significant differences between the two centres in 1-, 5-, 10- and 20-year cumulative incidence of death-censored graft-survival (p=0.10), end-stage renal disease (p=0.29) or de novo cancer (p=0.22). Nottingham had a lower incidence of major cardiovascular events (p=0.008).Conclusion: Adopting a new model of healthcare provides a means of delivering post-transplant patient care close to home, without compromising patient survival and long-term clinical outcomes

Performance of non-invasive tests and histology for the prediction of clinical outcomes in patients with non-alcoholic fatty liver disease: an individual participant data meta-analysis

BACKGROUND: Histologically assessed liver fibrosis stage has prognostic significance in patients with non-alcoholic fatty liver disease (NAFLD) and is accepted as a surrogate endpoint in clinical trials for non-cirrhotic NAFLD. Our aim was to compare the prognostic performance of non-invasive tests with liver histology in patients with NAFLD. METHODS: This was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0-4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0-2 vs F3 vs F4; LSM: 2·67; NFS: 0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226. FINDINGS: Of 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44-63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33-91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62-0·81) for histology, 0·76 (0·70-0·83) for LSM-VCTE, 0·74 (0·64-0·82) for FIB-4, and 0·70 (0·63-0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression. INTERPRETATION: Simple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases. FUNDING: Innovative Medicines Initiative 2

Performance of non-invasive tests and histology for the prediction of clinical outcomes in patients with non-alcoholic fatty liver disease: an individual participant data meta-analysis.

BACKGROUND Histologically assessed liver fibrosis stage has prognostic significance in patients with non-alcoholic fatty liver disease (NAFLD) and is accepted as a surrogate endpoint in clinical trials for non-cirrhotic NAFLD. Our aim was to compare the prognostic performance of non-invasive tests with liver histology in patients with NAFLD. METHODS This was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0-4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0-2 vs F3 vs F4; LSM: 2·67; NFS: 0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226. FINDINGS Of 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44-63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33-91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62-0·81) for histology, 0·76 (0·70-0·83) for LSM-VCTE, 0·74 (0·64-0·82) for FIB-4, and 0·70 (0·63-0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression. INTERPRETATION Simple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases. FUNDING Innovative Medicines Initiative 2

Diagnostic accuracy of non-invasive tests for advanced fibrosis in patients with NAFLD: an individual patient data meta-analysis

Objective: Liver biopsy is still needed for fibrosis staging in many patients with non-alcoholic fatty liver disease. The aims of this study were to evaluate the individual diagnostic performance of liver stiffness measurement by vibration controlled transient elastography (LSM- VCTE), Fibrosis-4 index (FIB-4) and NAFLD Fibrosis Score (NFS) and to derive diagnostic strategies that could reduce the need for liver biopsies.Design: Individual patient data meta-analysis of studies evaluating LSM-VCTE against liver histology was conducted. FIB-4 and NFS were computed where possible. Sensitivity, specificity and area under the receiver operating curve (AUROC) were calculated. Biomarkers were assessed individu-ally and in sequential combinations.Results: Data were included from 37 primary studies (n=5735; 45% female; median age: 54 years; median BMI: 30 kg/m2; 33% had type 2 diabetes; 30% had advanced fibrosis). AUROCs of individual LSM-VCTE, FIB-4 and NFS for advanced fibrosis were 0.85, 0.76 and 0.73. Sequential combination of FIB-4 cut-offs

Time to endoscopy for acute upper gastrointestinal bleeding: results from a prospective multicentre trainee-led audit

Background: Endoscopy within 24 hours of admission (early endoscopy) is a quality standard in acute upper gastrointestinal bleeding (AUGIB). We aimed to audit time to endoscopy outcomes and identify factors affecting delayed endoscopy (>24h of admission).Methods: This prospective multicentre audit enrolled patients admitted with AUGIB who underwent inpatient endoscopy between Nov-Dec 2017. Analyses were performed to identify factorsassociated with delayed endoscopy, and to compare patient outcomes, including length of stay and mortality rates, between early and delayed endoscopy groups.Results: Across 348 patients from 20 centres, the median time to endoscopy was 21.2h (IQR 12.0- 35.7), comprising median admission to referral and referral to endoscopy times of 8.1h (IQR 3.7- 18.1) and 6.7h (IQR 3.0-23.1) respectively. Early endoscopy was achieved in 58.9%, although this varied by centre (range: 31.0% - 87.5%, p=0.002). On multivariable analysis, lower Glasgow-Blatchford score, delayed referral, admissions between 7am-7pm or via the Emergency Department were independent predictors of delayed endoscopy. Early endoscopy was associated with reduced length of stay (median difference 1d; p= 0.004), but not 30-day mortality (p=0.344).Conclusions: The majority of centres did not meet national standards for time to endoscopy. Strategic initiatives involving acute care services may be necessary to improve this outcome

Performance of non-invasive tests and histology for the prediction of clinical outcomes in patients with non-alcoholic fatty liver disease: an individual participant data meta-analysis

BackgroundHistologically assessed liver fibrosis stage has prognostic significance in patients with non-alcoholic fatty liver disease (NAFLD) and is accepted as a surrogate endpoint in clinical trials for non-cirrhotic NAFLD. Our aim was to compare the prognostic performance of non-invasive tests with liver histology in patients with NAFLD.MethodsThis was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0–4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0–2 vs F3 vs F4; LSM: 2·67; NFS: 0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226.FindingsOf 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44–63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33–91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62–0·81) for histology, 0·76 (0·70–0·83) for LSM-VCTE, 0·74 (0·64–0·82) for FIB-4, and 0·70 (0·63–0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression.InterpretationSimple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases