Should we routinely measure portal pressure in patients with cirrhosis, using hepatic venous pressure gradient (HVPG) as a guide for prophylaxis and therapy of bleeding and rebleeding? No

Correlation of Hepatic Venous Pressure Gradient Level With Clinical and Endoscopic Parameters in Decompensated Chronic Liver Disease

BACKGROUND

The amount of liver fibrosis usually correlates with portal pressure, which is measured as the hepatic venous pressure gradient (HVPG). The fact that portal pressure significantly decreases after treatment may increase cirrhotic patients' long-term survival suggests that measuring HVPG may offer specific information for outcome prediction. The study thus seeks to determine the relationship between the level of the HVPG and endoscopic and clinical parameters in decompensated chronic liver disease (CLD).

METHODOLOGY

Thirty patients with CLD were studied and subjected to serum creatinine, total bilirubin, serum sodium, serum albumin, prothrombin time (PT), international normalized ratio (INR), esophagogastroduodenoscopy (upper gastrointestinal (UGI) endoscopy), and transjugular or transfemoral catheterization for HVPG measurement, and Child-Turcotte-Pugh (CTP) score and Model for End-Stage Liver Disease (MELD) score were calculated.

RESULTS

The results indicates a strong positive connection between MELD and HVPG, which is statistically significant (r=0.754; p<0.001). Similarly, CTP and HVPG also exhibit a significant positive association (r=0.793; p<0.001) suggesting a link between the severity of liver disease. Additionally, the moderate positive correlation for encephalopathy has a significant value (r=0.584; p=0.001), while the weak positive correlations for serum bilirubin, INR, and HVPG have non-significant values (r=0.244; p=0.194, and r=0.375; p=0.041, respectively). A strong negative connection between serum albumin and HVPG was also found (r=0.546; p=0.005) suggesting a relationship between worsening liver function.

CONCLUSION

In patients with decompensated CLD, the severity of the CLD as measured by the CTP and MELD score corresponds with HVPG, and higher HVPG associated with severe CLD and severe ascites, large varices, and variceal hemorrhage. Higher HVPG in cirrhotic patients also suggests the existence of sequelae, such as varices, severe ascites, and severe hepatic encephalopathy, although HVPG has little bearing on the underlying cause.

Liver stiffness-based model predicts hepatic venous pressure gradient in patients with liver disease

BACKGROUND

The aim was to develop a model to predict clinically significant portal hypertension, hepatic venous pressure gradient (HVPG) ≥10 mmHg using pre-operative noninvasive makers.

METHODS

Patients who have been programmed for liver resection/transplantation were enrolled prospectively. Preoperative liver stiffness measurement (LSM), liver function test (LFT), and intraoperative HVPG were assessed. A probability score model to predict HVPG≥10 mmHg called HVPG₁₀ score was developed and validated.

RESULTS

A total of 161 patients [66% men, median age of 63 years] were recruited for the study. Median LSM, and HVPG were 9.5 kPa, and 5 mmHg respectively. HVPG₁₀ score was developed using independent predictors of HVPG≥10 mmHg in the training set were LSM, total bilirubin, alkaline phosphatase, and international normalized ratio. Area under receiver operating curve of HVPG₁₀ score in the training and validation sets were 0.91 and 0.93 respectively with a cutoff of 15. In the overall cohort, HVPG₁₀ score≥15 had 83% accuracy, 90% sensitivity, 81% specificity and 96% negative predictive value in predicting HVPG≥10 mmHg.

CONCLUSION

HVPG₁₀ score is an easy-to-use noninvasive continuous scale tool to rule out clinically significant portal hypertension in >95% patients with chronic liver disease.

Characterization of mesenteric and portal hemodynamics using 4D flow MRI: the effects of meals and diurnal variation

PURPOSE

To determine the variability of blood flow measurements using 4D flow MRI in the portal and mesenteric circulations and to characterize the effects of meal ingestion, time of day, and between-day (diurnal) variations on portal and mesenteric hemodynamics.

METHODS

In this IRB-approved and HIPAA-compliant study, 7 healthy and 7 portal hypertension patients imaged. MRI exams were conducted at 3 T using a 32-channel body coil with large volumetric coverage and 1.25-mm isotropic true spatial resolution. Blood flow was quantified (L/min) in the hepatic and splanchnic vasculature. The first MR scan was performed after at least 8 h of fasting. Subsequently, subjects ingested 574 mL EnSure Plus® orally. A second acquisition was started 20 min after the meal ingestion. A third scan was performed before lunch and a fourth acquisition took place 20 min after lunch. A fifth scan was performed around 4 pm. Finally, subjects returned one week later for a repeat morning visit, with identical conditions as the first visit.

RESULTS

In healthy controls significant increase in blood flow was seen in the PV, SMV, SMA, HA, and SCAo in response to breakfast but only the SCAo, SMA, SMV, and PV had a significant response to lunch. In general, patients with cirrhosis showed reduced response to meals compared to that in healthy controls. Additionally, PV flow in patients had the highest value in the afternoon.

CONCLUSION

Effects of meal ingestion, time of day, and between-day variations were characterized using Radial 4D flow MRI in patients with cirrhosis and healthy controls.

Two-dimensional Shear Wave Elastography with Propagation Maps for the Assessment of Liver Fibrosis and Clinically Significant Portal Hypertension in Patients with Chronic Liver Disease: A Prospective Study

OBJECTIVES

To investigate the diagnostic performance of liver stiffness (LS) measurements on two-dimensional (2D) shear wave elastography (SWE) for the assessment of hepatic fibrosis using LS measurements on MR elastography (MRE) as the reference standard and the prediction of clinically significant portal hypertension (CSPH).

METHODS

In this prospective study, 101 patients with chronic liver disease or cirrhosis underwent both MRE and SWE. After exclusion of technical failure on MRE (n = 5), technical failure/unreliable measurement on SWE (n = 4), LS measurements obtained on SWE with the aid of propagation maps were correlated with those of the MRE using Pearson's correlation analysis. Diagnostic performances for significant fibrosis (≥F2: MRE of ≥2.99 kPa) or cirrhosis (F4: MRE of ≥3.63 kPa) and for the prediction of CSPH were assessed using receiver operating characteristics (ROC) curve analysis.

RESULTS

LS values on SWE showed a strong correlation with those on MRE (r = 0.846, P < 0.001). For the diagnosis of significant fibrosis or cirrhosis in patients with hepatitis B virus-related liver disease (n = 75), SWE showed areas under the ROC curves (AUC) of 0.975 and 0.912, respectively (95% confidence interval [CI], 0.910-997, and 0.824-0.965). For the prediction of CSPH, the AUC of SWE was 0.818 (95% CI, 0.712-0.898), and when an LS value of 11.5 kPa was applied as a cut-off, SWE showed a sensitivity of 81.5% and a specificity of 72.9%.

CONCLUSION

LS measurements on 2D SWE were demonstrated to be well correlated with those obtained with MRE, and thus, may provide good diagnostic performance for the prediction of hepatic fibrosis and the presence of CSPH.

The predictive value of baseline hepatic venous pressure gradient for variceal rebleeding in cirrhotic patients receiving secondary prevention

BACKGROUND

Baseline hepatic venous pressure gradient (HVPG) has been applied for prediction of variceal rebleeding in patients after acute variceal bleeding. However, for patients receiving secondary prevention, there still lacks evidence about the predictive performance of baseline-HVPG for rebleeding. This study aims to investigate the predictive value of baseline-HVPG for variceal rebleeding in cirrhotic patients receiving secondary prevention.

METHODS

This retrospective study included 122 patients with cirrhosis accepting secondary prevention of variceal rebleeding in a university hospital. All the included patients had HVPG measurements before rebleeding and had at least 1-year follow-up after HVPG measurement unless the rebleeding occurred. The rebleeding rate in patients with different HVPG levels and time-dependent predictive performance of baseline-HVPG were analysed. A Cox regression model and P for trend were used to assess the rebleeding risk.

RESULTS

Variceal rebleeding occurred in 22 (18.0%) patients during 1-year follow-up. No significant difference was observed in rebleeding rate between patients with HVPG <16 mmHg and HVPG ≥16 mmHg (17.91% vs. 26.41%, P=0.200). A decreasing trend was observed in area under the curve of HVPG for predicting rebleeding by time. The multivariate Cox model showed an overall decreasing trend in hazard ratio of rebleeding (vs. patients with HVPG <12 mmHg) for patients with 12≤ HVPG <16 mmHg, 16≤ HVPG <20 mmHg and HVPG ≥20 mmHg; besides, an increasing P for trend was observed.

CONCLUSIONS

A single baseline-HVPG measurement was insufficient for predicting rebleeding in patients with cirrhosis who received secondary prevention.

Non-invasive assessment of portal hypertension by multi-parametric magnetic resonance imaging of the spleen: A proof of concept study

BACKGROUND AND AIMS

Non-invasive assessment of portal hypertension is an area of unmet need. This proof of concept study aimed to evaluate the diagnostic accuracy of a multi-parametric magnetic resonance technique in the assessment of portal hypertension. Comparison to other non-invasive technologies was a secondary aim.

METHODS

T1 and T2* maps through the liver and spleen were acquired prior to trans-jugular liver biopsy and hepatic vein pressure gradient (HVPG) measurement. T1 measurements reflect changes in tissue water content, but this relationship is confounded by the presence of iron, which in turn can be quantified accurately from T2* maps. Data were analysed using LiverMultiScan (Perspectum Diagnostics, Oxford, UK) which applies an algorithm to remove the confounding effect of iron, yielding the "iron corrected T1" (cT1). Sensitivity, specificity, diagnostic values and area under the curve were derived for spleen cT1, liver cT1, transient elastography, and serum fibrosis scores. HVPG was the reference standard.

RESULTS

Nineteen patients (15 men) with median age 57 years were included. Liver disease aetiologies included non-alcoholic fatty liver disease (n = 9; 47%) and viral hepatitis (n = 4; 21%). There was strong correlation between spleen cT1 and HVPG (r = 0.69; p = 0.001). Other non-invasive biomarkers did not correlate with HVPG. Spleen cT1 had excellent diagnostic accuracy for portal hypertension (HVPG >5 mmHg) and clinically significant portal hypertension (HVPG ≥10 mmHg) with an area under the receiver operating characteristic curve of 0.92 for both.

CONCLUSION

Spleen cT1 is a promising biomarker of portal pressure that outperforms other non-invasive scores and should be explored further.

Endoscopic Ultrasound-Guided Interventions for the Measurement and Treatment of Portal Hypertension

The number of endoscopic ultrasound (EUS)-guided interventions is rapidly growing within advanced endoscopy. EUS offers high-resolution imaging of mediastinal and intra-abdominal vasculature, which can be targeted for various interventions, hence a growing number of studies have explored EUS-guided vascular catheterization. Potential clinical applications of EUS-guided portal venous access include angiography, measurement of the portosystemic pressure gradient, and EUS-guided transhepatic intrahepatic portosystemic shunt creation. This article reviews different devices and techniques used in these applications.

Lowering hepatic venous pressure agent carvedilol versus variceal banding ligation for clinical outcomes of cirrhotic portal hypertension

OBJECTIVE

Carvedilol is nonselective beta-blocker with a mild anti-alpha-1-adrenergic effect. Several studies proposed improved hemodynamic effects of carvedilol compared with propanolol. Our study was to perform a systematic review and meta-analysis of randomized control trials comparing carvedilol with variceal banding ligation (VBL).

METHODS

Studies were searched on online databases MEDLINE, EMBASE(Ovid), the Cochrane Library, Chinese Wanfang Database, and China National Knowledge Infrastructure between January 2000 and May 2018. Incidence of bleeding and mortality were main outcome measures. Subgroup analysis and sensitivity analysis were conducted to ensure the robustness of pooled estimates.

RESULTS

Ten randomized control trials including 1,269 cirrhotic patients were chosen. Compared with VBL, carvedilol showed similar preventive efficacy of risk ratios (RRs) in variceal bleeding, and bleeding-related mortality over different follow-up periods from 6 months to 24 months. Also, significant differences between carvedilol and VBL in overall mortality and other causes of mortality were failed to be found. Carvedilol achieved a lower incidence of portal hypertension gastropathy in both 6 months (RR=0.49, 95% CI: 0.38-0.64, P<0.00001) and 12 months (RR=0.35, 95% CI: 0.26-0.47, P<0.00001). Two trials compared combination of carvedilol and VBL with VBL alone; however, the results failed to find an improved preventive efficacy of bleeding (RR=0.71, 95% CI: 0.15-3.30, P=0.67).

CONCLUSION

Carvedilol is equivalent to invasive VBL for variceal bleeding prevention. It can be well tolerated and may be of benefit to portal hypertension gastropathy. However, available data during 24 months follow-up did not support a potential advantage of carvedilol for prognosis as a lowering hepatic venous pressure agent.

EUS-guided portal pressure gradient measurement with a simple novel device: a human pilot study

BACKGROUND AND AIMS

Portal hypertension is a serious adverse event of liver cirrhosis. Recently, we developed a simple novel technique for EUS-guided portal pressure gradient (PPG) measurement (PPGM). Our animal studies showed excellent correlation between EUS-PPGM and interventional radiology-acquired PPGM. In this video we demonstrate the results of the first human pilot study of EUS-PPGM in patients with liver disease.

METHODS

EUS-PPGM was performed by experienced endosonographers using a linear echoendoscope, a 25-gauge FNA needle, and a novel compact manometer. The portal vein and hepatic vein (or inferior vena cava) were targeted by use of a transgastric or transduodenal approach. Feasibility was defined as successful PPGM in each patient. Safety was based on adverse events captured in a postprocedural interview.

RESULTS

Twenty-eight patients underwent EUS-PPGM with 100% technical success and no adverse events. PPG ranged from 1.5 to 19 mm Hg and had excellent correlation with clinical parameters of portal hypertension, including the presence of varices (P = .0002), PH gastropathy (P = .007), and thrombocytopenia (P = .036).

CONCLUSION

This novel technique of EUS-PPGM using a 25-gauge needle and compact manometer is feasible and appears safe. Given the availability of EUS and the simplicity of the manometry setup, EUS-guided PPG may represent a promising breakthrough for procuring indispensable information in the management of patients with liver disease.

Endoscopic Ultrasound-Guided Portal Pressure Measurement and Interventions

A growing number of studies have explored endoscopic ultrasound (EUS)-guided vascular catheterization. Potential clinical applications of EUS-guided portal venous access include angiography, measurement of the portosystemic pressure gradient, EUS-guided transhepatic intrahepatic portosystemic shunt creation and portal vein sampling for the evaluation in gastrointestinal cancer. The following article reviews the different devices and techniques employed in these applications.

EUS-guided portal pressure measurement (with videos)

A growing number of studies have explored EUS-guided vascular catheterization due to the relative proximity of the gastrointestinal tract to the major blood vessels of the mediastinum and abdomen. In particular, EUS-guided access of the portal vein (PV) may be favorable given the relative difficulty of PV access through standard percutaneous routes. Two major diagnostic applications of EUS-guided vascular access include angiography and assessment of intravascular pressure. This review will outline the different devices and techniques employed to obtain angiographic visualization and/or direct pressure measurements of the portal circulation. Ease of access, safety, and important lessons learned from each approach will be highlighted.

Hepatic venous pressure gradient correlates with advanced hepatic fibrosis: a retrospective review

PURPOSE

To determine if hepatic venous pressure gradient (HVPG) correlates with advanced hepatic fibrosis, as a complement to transjugular (transvenous) core needle liver biopsy.

MATERIALS AND METHODS

After institutional review board approval, a retrospective review was conducted on 340 patients who underwent transjugular (transvenous) core needle liver biopsy with concurrent pressure measurements between 6/1/2007 and 6/1/2013. Spearman correlation and linear regression were performed. A receiver operating characteristic (ROC) curve was created and sensitivity, specificity, predictive values and likelihood ratios were calculated.

RESULTS

Indications included hepatitis C, abnormal liver function tests, non-alcoholic steatohepatitis, autoimmune hepatitis, and cirrhosis, among others. Biopsies showed stage 1 or 2 fibrosis in 15.6% each, stage 3 fibrosis in 21.6%, stage 4 fibrosis in 40.7%, and no fibrosis in 6.5%. Mean HVPG was 6.5 mm Hg (SD 5.0) with a range of 0-26 mm Hg. Spearman correlation coefficient for association between HVPG and fibrosis stage was 0.561 (p < 0.001). R2 on linear regression was 0.247 (p < 0.001). ROC curve for the prediction of stage 4 fibrosis had an area under the curve of 0.79 (95% CI 0.73-0.85). HVPG of ≥6 mm Hg had a sensitivity of 71.3%, specificity of 79.6%, positive predictive value of 70.5%, negative predictive value of 80.2%, positive likelihood ratio of 3.49 (95% CI 2.45-4.97) and negative likelihood ratio of 0.36 (95% CI 0.26-0.50) for diagnosis of stage 4 fibrosis.

CONCLUSIONS

HVPG correlates with stage 4 (advanced) hepatic fibrosis.

EUS-guided portal pressure gradient measurement with a simple novel device: a human pilot study

BACKGROUND AND AIMS

Portal hypertension (PH) is a serious adverse event of liver cirrhosis. The hepatic venous pressure gradient or portal pressure gradient (PPG) accurately reflects the degree of PH and is the single best prognostic indicator in liver disease. This is usually obtained by interventional radiology (IR), although it is not routinely performed. Recently, we developed a simple novel technique for EUS-guided PPG measurement (PPGM). Our animal studies showed excellent correlation between EUS-PPGM and IR-PPGM. We present the first human pilot study of EUS-PPGM in patients with liver disease.

METHODS

EUS-PPGM was performed by experienced endosonographers using a linear echoendoscope, a 25-gauge fine-needle aspiration needle, and a novel compact manometer. The portal vein and hepatic vein (or inferior vena cava) were targeted using a transgastric-transduodenal approach. Clinical parameters of PH were evaluated in each patient. Feasibility was defined as successful PPGM in each patient. Safety was based on adverse events captured in a postprocedural interview.

RESULTS

Twenty-eight patients underwent EUS-PPGM with 100% technical success and no adverse events. PPG ranged from 1.5 to 19 mm Hg and had excellent correlation with clinical parameters of portal hypertension including the presence of varices (P = .0002), PH gastropathy (P = .007), and thrombocytopenia (P = .036). PPG was increased in patients with high clinical evidence of cirrhosis (P = .005).

CONCLUSION

This novel technique of EUS-PPGM using a 25-gauge needle and compact manometer is feasible and appears safe. Given the availability of EUS and the simplicity of the manometry setup, EUS-guided PPG may represent a promising breakthrough for procuring indispensable information in the management of patients with liver disease.

Endoscopic Ultrasound-Guided Direct Portal Pressure Measurement Using a Digital Pressure Wire with Real-Time Remote Display: A Survival Study

BACKGROUND

Portal hypertension is necessary for the development of most clinical complications of cirrhosis. We recently reported a novel, endoscopic ultrasound (EUS)-guided technique for direct portal pressure measurements using a digital pressure wire.

AIMS

The aims of this study were to (1) evaluate safety in an animal survival model and (2) compare direct portal vein (PV) versus transhepatic access of a first-order venule.

MATERIALS AND METHODS

Yorkshire pigs, weighing 40-55 kg. Procedures were performed under general anesthesia. PV was identified using a linear array echoendoscope and accessed with a 22-G fine needle aspiration needle preloaded with a digital pressure wire. Access was confirmed by portal venography. Mean digital pressure measurements were recorded over 30 seconds, and again after accessing a first-order portal venule in a transhepatic manner. Procedure times and video logs were maintained throughout. Animals were survived for 2 weeks. Repeat portal pressure measurements were performed before euthanasia and necropsy.

RESULTS

EUS-guided portal pressure measurements ranged from 3 to 11 mm Hg (mean 6.1) and were performed in a mean time of 214 seconds. There was no difference in measurement between the PV and first-order venule, or between baseline and 2-week follow-up. Five of 5 animals survived without incident. On necropsy, there was no evidence of thrombus or hemorrhage.

CONCLUSIONS

This study represents the first survival study after EUS-guided direct portal pressure measurements using a digital pressure wire. This method appears safe, straightforward, and precise. Measurements of the PV and a first-order portal venule appear equivalent, and serial measurement seems feasible.

Hemodynamic response to primary prophylactic therapy with nonselective β-blockers is related to a reduction of first variceal bleeding risk in liver cirrhosis: a meta-analysis

The current primary prophylaxis for esophageal variceal bleeding in cirrhotic patients consists of nonselective β-blocker (NSBB) therapy. However, only approximately half of the patients achieve a sufficient hemodynamic response to NSBB therapy. Clinical application of hemodynamic response monitoring is still under debate. The aim of this meta-analysis is to assess the potential clinical value of monitoring the hemodynamic response to NSBB therapy using hepatic venous pressure gradient (HVPG) measurements in the primary prophylaxis for variceal bleeding. A systematic literature search was performed in PubMed, Embase, Web of Science, and the COCHRANE Library. Randomized-controlled trials and case series that included cirrhotic patients receiving primary prophylaxis for variceal bleeding with NSBBs and hemodynamic response monitoring using HVPG measurements were included for analysis. The primary outcome measure was variceal bleeding. A fixed-effect analysis was carried out using the Mantel-Haenszel method for relative risks. Six of the 1172 papers found were selected on the basis of stringent selection criteria. Hemodynamic response (HVPG ≤12 mmHg and/or a reduction of ≥20%, or ≥10% in one study, from baseline) to β-blocker therapy was associated significantly with a lower risk of variceal bleeding (relative risk=0.13, 95% confidence interval=0.06-0.29) compared with a nonresponse. Patients achieving a hemodynamic response to NSBB therapy have a lower risk of variceal bleeding than hemodynamic nonresponders. Hemodynamic monitoring in primary prophylaxis is of potential clinical value and requires further assessment in large cohort randomized-controlled trials.

EUS-guided intrahepatic portosystemic shunt with direct portal pressure measurements: a novel alternative to transjugular intrahepatic portosystemic shunting

BACKGROUND AND AIMS

Transjugular intrahepatic portosystemic shunting involves the creation of a low-resistance channel between the portal vein (PV) and the hepatic vein (HV), and is routinely performed under angiography. The aims were to evaluate (1) safety and technical feasibility; (2) procedural duration; and (3) subjective workload assessment of EUS-guided intrahepatic portosystemic shunt (EIPS).

METHODS

Five Yorkshire pigs were used in the study. The HV or inferior vena cava (IVC) was identified using a linear-array echoendoscope and accessed with a 19-G FNA needle preloaded with a digital pressure wire. Mean pressure was recorded. The needle was advanced into the PV, where pressure measurements were again taken, and ultimately exchanged over a guidewire. A lumen-apposing metal stent was deployed under EUS and fluoroscopic guidance, with distal and proximal ends positioned inside the PV and HV (IVC), respectively. Dilation was performed, and pressure measurements repeated. The National Aeronautics and Space Administration (NASA) Task Load Index (TLI) was scored. Animals survived 2 weeks before necropsy.

RESULTS

EIPS was successful in 5 out of 5 pigs. Mean time required for EUS identification, needle access, pressure measurement, and stent placement was 43 (31-55) minutes. NASA TLI scores revealed moderate workload. Mean baseline pressure measurements were PV 7.0 (5-9) and HV/IVC 5.0 (3-7) mm Hg and PV 6.3 (5-7) and HV/IVC 6.0 (4-7) mm Hg after. All animals survived 2 weeks. No bleeding was seen on necropsy.

CONCLUSIONS

This study demonstrates the technical feasibility of EIPS using LAMS, with direct portal pressure measurement, in a survival model. In addition, the procedure was performed quickly with moderate technical demand.

Diagnosis of Clinically Significant Portal Hypertension in Patients with Cirrhosis: Splenic Arterial Resistive Index versus Liver Stiffness Measurement

The purpose of the present study is to compare the diagnostic accuracy of the splenic arterial resistive index (SARI) with that of liver stiffness measurement (LSM) for identifying patients with clinically significant portal hypertension (CSPH). We included 47 patients (M:F = 37:10) who underwent Doppler ultrasonography, LSM and hepatic venous pressure gradient (HVPG) on the same day. We investigated whether the SARI and LSM were correlated with the HVPG, and compared area under the curve (AUC) values for the abilities of SARI and LSM to diagnose CSPH. We also performed a sub-group analysis. The SARI and LSM were all moderately correlated with HVPG overall in patients. The AUC of SARI and LSM were 0.873 and 0.745, respectively. In patients without splenomegaly, SARI was strongly correlated with HVPG (r = 0.830), but LSM was moderately correlated with HVPG (r = 0.601). The AUC was also higher for SARI than for LSM. Therefore, SARI is potentially an excellent non-invasive measurement method for diagnosing CSPH, especially those without splenomegaly.

EUS-guided portal pressure measurement using a digital pressure wire with real-time remote display: a novel, minimally invasive technique for direct measurement in an animal model

BACKGROUND AND AIMS

Hepatic venous pressure gradient (HVPG) currently serves as a surrogate for portal pressure measurement but has many limitations. We developed a novel technique for rapid and direct portal pressure measurements using a digital pressure wire delivered through an EUS-guided 22-gauge FNA needle. Our aims were to evaluate (1) the short-term safety and technical feasibility, (2) procedural duration and subjective workload assessment, and (3) accuracy compared with a transjugular criterion standard approach.

METHODS

The subjects were Yorkshire pigs, weighing 40 to 55 kg. The portal vein was identified by using a linear array echoendoscope and accessed with a commercially available 22-gauge FNA needle preloaded with a digital pressure wire. Access was confirmed by portal venography. Mean digital pressure measurements were recorded over 30 to 60 seconds, and the National Aeronautics and Space Administration Task Load Index was scored. The control measurements were conventional transjugular catheterization with a balloon occlusion catheter to obtain free and wedged hepatic pressures, with subsequent HVPG calculation.

RESULTS

The total time required for EUS identification and needle access of the portal vein, venography, and digital pressure measurement was less than 5 minutes in 5 of 5 pigs. The National Aeronautics and Space Administration Task Load Index scores revealed a low subjective workload. Baseline portal pressure measurements via EUS ranged from 5 mm Hg to 10 mm Hg (mean, 6.4 mm Hg). HVPG measurements were consistently ±1 mm Hg of portal pressure.

CONCLUSIONS

This study is the first report of direct EUS-guided portal pressure measurements by using a digital pressure wire. This method is routinely performed in minutes and provides real-time pressure tracings via wireless transmission. This novel approach for direct portal pressure measurement has the potential to replace traditional indirect HVPG measurements.

Correlation of HVPG level with ctp score, MELD Score, ascites, size of varices, and etiology in cirrhotic patients

BACKGROUND/AIM

This study intends to determine the correlation of a patient's hepatic venous pressure gradient (HVPG) measurement with six factors: Child-Turcotte-Pugh (CTP) score, model for end-stage liver disease (MELD) score, presence of ascites, size of varices, presence of variceal bleeding, and an etiology of cirrhosis. The study also aims to identify the predictors of higher HVPG measurements that can indirectly affect the prognosis of cirrhotic patients.

PATIENTS AND METHODS

Thirty patients diagnosed with cirrhosis were enrolled prospectively and each patient's HVPG level was measured by the transjugular catheterization of the right or middle hepatic vein. The wedged hepatic venous pressure (WHVP) and free hepatic venous pressure (FHVP) were measured using a 7F balloon catheter. The HVPG level was calculated as the difference between the WHVP and FHVP measurements.

RESULTS

The mean HVPG level was higher in alcoholic than in nonalcoholic cirrhosis (19.5 ± 7.3 vs 15.2 ± 4.5 mm Hg, P = 0.13). The mean HVPG was also higher in bleeders compared with nonbleeders (18.5 ± 5.3 vs 10.7 ± 3.1 mmHg, P = 0.001). Patients with varices had a higher mean HVPG level than those without varices (17.4 ± 5.8 vs 11.7 ± 3.9 mmHg, P = 0.04). The difference among the three categories of varices (small, large, and no varices) was statistically significant (P = 0.03). In addition, the mean HVPG level was higher in patients with ascites than in those without ascites (18.7 ± 4.7 vs 11 ± 5.3 mmHg, P = 0.002), and it was significantly higher in patients in CTP class C (21.8 ± 5.5 mmHg) as compared with those in CTP class B (16.9 ± 2.9 mmHg) and CTP class A (10.5 ± 4.1 mmHg; P ≤ 0.001).

CONCLUSION

HVPG levels were significantly higher in patients in CTP class C as compared with those in CTP classes A and B, thereby indicating that an HVPG measurement correlates with severity of liver disease. A high HVPG level signifies more severe liver disease and can predict the major complications of cirrhosis.

Shear-wave elastography: a noninvasive tool for monitoring changing hepatic venous pressure gradients in patients with cirrhosis

PURPOSE

To investigate whether liver stiffness ( LS liver stiffness ) and change in LS liver stiffness measurements ( ΔLS change in LS ) at shear-wave elastography ( SWE shear-wave elastography ) correlates with the hepatic venous pressure gradient ( HVPG hepatic venous pressure gradient ) and to assess the feasibility of using SWE shear-wave elastography to estimate the change in HVPG hepatic venous pressure gradient ( ΔHVPG change in HVPG ) in patients with portal hypertension.

MATERIALS AND METHODS

Institutional review board approval was obtained, with waiver of informed consent. Between September 2010 and October 2012, 97 consecutive patients who were given a diagnosis of portal hypertension on the basis of HVPG hepatic venous pressure gradient measurement were included. Among these patients, 23 who underwent follow-up HVPG hepatic venous pressure gradient measurement to evaluate response to treatment were included in the follow-up group. The correlation between HVPG hepatic venous pressure gradient and LS liver stiffness was analyzed by using the Pearson correlation test. In the follow-up group, whether ΔHVPG change in HVPG was correlated with ΔLS change in LS was also evaluated. Thereafter, the areas under the receiver operating characteristic curves ( AUC area under the ROC curve s) were calculated to determine the diagnostic performances of ΔLS change in LS and the second LS liver stiffness measurement after medical treatment and to compare their performances in association with clinical improvement and aggravation of portal hypertension.

RESULTS

LS liver stiffness was moderately correlated with HVPG hepatic venous pressure gradient (r = 0.593) in the single-measurement group. There was also a strong correlation between ΔLS change in LS and ΔHVPG change in HVPG (r = 0.863). At comparison of the second LS liver stiffness measurement, ΔLS change in LS showed no significant difference in AUC area under the ROC curve in patients with improvement (0.627 vs 0.794, P = .201) but showed higher AUC area under the ROC curve in association with aggravation of portal hypertension (0.925 vs 0.611, P = .026).

CONCLUSION

Estimating ΔHVPG change in HVPG by using SWE shear-wave elastography may be useful in patients with cirrhosis and portal hypertension.

Effect of temporal resolution on 4D flow MRI in the portal circulation

PURPOSE

To demonstrate the use of temporal averaging with radial 4D flow magnetic resonance imaging (MRI) to reduce scan time for quantification and visualization of flow in the portal circulation. This study compared phase-contrast MR angiography, 3D flow visualization, and flow quantification of portal venous hemodynamics of time-averaged vs. time-resolved reconstructions.

MATERIALS AND METHODS

Time-resolved 3D radial ("4D") phase contrast data were acquired from 44 subjects (15 volunteers, 29 cirrhosis patients) at 3T. Images were reconstructed as a fully sampled time-resolved reconstruction and multiple time-averaged reconstructions using a variable number of acquired projections to simulate different scan times. Images from each reconstruction were evaluated to compare the quality of anatomical and hemodynamic visualization.

RESULTS

Time-averaged reconstructions outperformed time-resolved reconstructions for flow quantification (3.9 ± 3.1% error vs. 5.2 ± 4.4% error), average streamline length (47 ± 7 mm vs. 34 ± 15 mm), and visualization quality (average grading = 3.7 ± 0.5 vs. 2.2 ± 0.9). In addition, excellent visualization quality was achieved using fewer acquired projections.

CONCLUSION

Reductions in scan time can be achieved through time-averaging while still providing excellent visualization and quantification in the portal circulation. Scan time reduction of up to 70%-80% was possible for high-quality assessment, translating into a reduction in scan time from 10-12 minutes to ∼3-4 minutes.

Transjugular liver biopsy: indications, technique and results

Transjugular liver biopsy is a safe, effective and well-tolerated technique to obtain liver tissue specimens in patients with diffuse liver disease associated with severe coagulopathies or massive ascites. Transjugular liver biopsy is almost always feasible. The use of ultrasonographic guidance for percutaneous puncture of the right internal jugular vein is recommended to decrease the incidence of local cervical minor complications. Semiautomated biopsy devices are very effective in obtaining optimal tissue samples for a precise and definite histological diagnosis with a very low rate of complication. The relative limitations of transjugular liver biopsy are the cost, the radiation dose given to the patient, the increased procedure time by comparison with the more common percutaneous liver biopsy, and the need of a well-trained interventional radiologist.

In vivo validation of 4D flow MRI for assessing the hemodynamics of portal hypertension

PURPOSE

To implement and validate in vivo radial 4D flow MRI for quantification of blood flow in the hepatic arterial, portal venous, and splanchnic vasculature of healthy volunteers and patients with portal hypertension.

MATERIALS AND METHODS

Seventeen patients with portal hypertension and seven subjects with no liver disease were included in this Health Insurance Portability and Accountability Act (HIPAA)-compliant and Institutional Review Board (IRB)-approved study. Exams were conducted at 3T using a 32-channel body coil with large volumetric coverage and 1.4 mm isotropic true spatial resolution. Using postprocessing software, cut-planes orthogonal to vessels were used to quantify flow (L/min) in the hepatic and splanchnic vasculature.

RESULTS

Flow quantification was successful in all cases. Portal vein and supraceliac aorta flow demonstrated high variability among patients. Measurements were validated indirectly using internal consistency at three different locations within the portal vein (error = 4.2 ± 3.9%) and conservation of mass at the portal confluence (error = 5.9 ± 2.5%) and portal bifurcation (error = 5.8 ± 3.1%).

CONCLUSION

This work demonstrates the feasibility of radial 4D flow MRI to quantify flow in the hepatic and splanchnic vasculature. Flow results agreed well with data reported in the literature, and conservation of mass provided indirect validation of flow quantification. Flow in patients with portal hypertensions demonstrated high variability, with patterns and magnitude consistent with the hyperdynamic state that commonly occurs in portal hypertension.

Progress in prevention and treatment of rebleeding after endoscopic band ligation for esophageal variceal bleeding

Hemorrhage from esophageal varices is a serious and common complication of decompensated cirrhosis and carries a significant rate of morbidity and mortality. Endoscopic variceal ligation (EVL) is an effective treatment for esophageal varices; however, there is a very high rate of rebleeding. Prevention and treatment of rebleeding after EVL are important for improving survival in patients with liver cirrhosis. Currently, many measures, including endoscopy, surgery, medication, and a combination of them, have been developed to prevent the occurrence of rebleeding after EVL. Many clinical trials have been done to evaluate the effectiveness of various treatments, alone or in combination, for rebleeding.

Indications for portal pressure measurement in chronic liver disease

Portal hypertension leads to development of serious complications such as esophageal varices, ascites, renal and cardiovascular dysfunction. The importance of the degree of portal hypertension has been substantiated within recent years. Measurement of the portal pressure is simple and safe and the hepatic venous pressure gradient (HVPG) independently predicts survival and development of complications such as ascites, HCC and bleeding from esophageal varices. Moreover, measurements of HVPG can be used to guide pharmacotherapy for primary and secondary prophylaxis for variceal bleeding. Assessment of HVPG should therefore be considered as a part of the general characterization of patients with portal hypertension in departments assessing and treating this condition.

Use of portal pressure studies in the management of variceal haemorrhage

Portal hypertension occurs as a complication of liver cirrhosis and complications such as variceal bleeding lead to significant demands on resources. Endoscopy is the gold standard method for screening cirrhotic patients however universal endoscopic screening may mean a lot of unnecessary procedures as the presence of oesophageal varices is variable hence a large time and cost burden on endoscopy units to carry out both screening and subsequent follow up of variceal bleeds. A less invasive method to identify those at high risk of bleeding would allow earlier prophylactic measures to be applied. Hepatic venous pressure gradient (HVPG) is an acceptable indirect measurement of portal hypertension and predictor of the complications of portal hypertension in adult cirrhotics. Varices develop at a HVPG of 10-12 mmHg with the appearance of other complications with HPVG > 12 mmHg. Variceal bleeding does not occur in pressures under 12 mmHg. HPVG > 20 mmHg measured early after admission is a significant prognostic indicator of failure to control bleeding varices, indeed early transjugular intrahepatic portosystemic shunt (TIPS) in such circumstances reduces mortality significantly. HVPG can be used to identify responders to medical therapy. Patients who do not achieve the suggested reduction targets in HVPG have a high risk of rebleeding despite endoscopic ligation and may not derive significant overall mortality benefit from endoscopic intervention alone, ultimately requiring TIPS or liver transplantation. Early HVPG measurements following a variceal bleed can help to identify those at risk of treatment failure who may benefit from early intervention with TIPS. Therefore, we suggest using HVPG measurement as the investigation of choice in those with confirmed cirrhosis in place of endoscopy for intitial variceal screening and, where indicated, a trial of B-blockade, either intravenously during the initial pressure study with assessment of response or oral therapy with repeat HVPG six weeks later. In those with elevated pressures, primary medical prophylaxis could be commenced with subsequent close monitoring of HVPG thus negating the need for endoscopy at this point. All patients presenting with variceal haemorrhage should undergo HVPG measurement and those with a gradient greater than 20 mmHg should be considered for early TIPS. By introducing portal pressure studies into a management algorithm for variceal bleeding, the number of endoscopies required for further intervention and follow up can be reduced leading to significant savings in terms of cost and demand on resources.

Noninvasive evaluation of portal hypertension: emerging tools and techniques

Portal hypertension is the main cause of complications in patients with cirrhosis. However, evaluating the development and progression of portal hypertension represents a challenge for clinicians. There has been considerable focus on the potential role of noninvasive markers of portal hypertension that could be used to stratify patients with respect to the stage of portal hypertension and to monitor disease progression or treatment response in a longitudinal manner without having to undertake repeated invasive assessment. The pathogenesis of portal hypertension is increasingly understood and emerging knowledge of the vascular processes that underpin portal hypertension has paved the way for exploring novel biomarkers of vascular injury, angiogenesis, and endothelial dysfunction. In this paper we focus on the pathogenesis of portal hypertension and potential non-invasive biomarkers with particular emphasis on serum analytes.