Hepatic venous pressure gradient: worth another look?

Feasibility and safety of ultrasound-guided percutaneous transhepatic measurement of portal venous pressure

BACKGROUND AND OBJECTIVE

The measurement of portal venous pressure (PVP) has been extensively studied, primarily through indirect methods. However, the potential of ultrasound-guided percutaneous transhepatic PVP measurement as a direct method has been largely unexplored. This study aimed to investigate the accuracy, safety, and feasibility of this approach.

METHODS

In vitro, the experiment aimed to select a needle that could accurately transmit pressure, had a small inner diameter and was suitable for liver puncture, and performed on 20 healthy New Zealand white rabbits. An ultrasound-guided percutaneous transhepatic portal vein puncture was undertaken to measure PVP. Additionally, free hepatic venous pressure (FHVP) and wedged hepatic venous pressure (WHVP) were measured under digital subtraction angiography (DSA). The correlation between the two methods was assessed. Enroll study participants from October 18, 2023 to November 11, 2023 with written informed consent. Five patients were measured the PVP under ultrasound guidance before surgery to determine the feasibility of this measurement method.

RESULTS

There was no significant difference in the results obtained using 9 different types of needles (P > 0.05). This demonstrated a great repeatability (P < 0.05). The 22G chiba needle with small inner diameter, allowing for accurate pressure transmission and suitable for liver puncture, was utilized for percutaneous transhepatic PVP measurement. There were positive correlations between PVP and HVPG (r = 0.881), PVP and WHVP (r = 0.709), HVPG and WHVP (r = 0.729), IVCP and FHVP (r = 0.572). The PVP was accurately and safely measured in 5 patients with segmental hepatectomy. No complications could be identified during postoperative ultrasound.

CONCLUSION

Percutaneous transhepatic portal venous puncture under ultrasound guidance is accurate, safe and feasible to measure portal venous pressure.

CLINICAL TRIAL REGISTRATION NUMBER

This study has been registered in the Chinese Clinical Trial Registry with registration number ChiCTR2300076751.

Endohepatology in clinical practice: EUS-guided portal pressure measurement combined with EUS-guided liver biopsy and variceal screening and treatment in outpatients

Background and Objectives

EUS-guided portal pressure gradient (PPG) is a novel technique that permits a true, direct measure of portal vein pressure and hepatic vein pressure. This article details our experience and lessons learned from 20 consecutive outpatient EUS-PPG procedures performed at a single center, along with simultaneous EUS-guided liver biopsy, variceal screening, and variceal banding.

Methods

Data on the first 20 patients who underwent EUS-PPG at a single center were retrospectively viewed and analyzed. The effects of various liver diseases or other patient-related factors on the clinical and technical success of EUS-PPG measurements, as well as EUS-guided liver biopsy (EUS-LB), were evaluated. During the procedure, if esophageal varices were encountered, they were assessed, and if felt to be clinically indicated, endoscopic variceal ligation was performed.

Results

The 20 patients included 10 male and 10 female patients. All procedures were technically successful. In all patients, the portal vein and hepatic veins could be easily identified. One adverse event of bleeding occurred during the EUS-PPG measuring procedure. All 20 EUS-LBs were technically successful and yielded adequate samples for histological evaluations, with an average of 25 complete portal tracts per sample. Among patients with esophageal varices, 40% of patients underwent banding. The mean EUS-PPG among 5 patients with esophageal varices was 11.6 mm Hg, compared with 3.2 mm Hg among 15 patients without esophageal varices.

Conclusion

This study demonstrates that EUS-PPG is a novel, safe, reproducible, and effective technique. Also, the fact that EUS-PPG, EUS-LB, variceal screening, and variceal banding could be performed in 1 session and on an outpatient basis speaks to the growing relevance and impact of the nascent field of endohepatology.

Endoscopic ultrasound-guided portal pressure gradient measurement in managing portal hypertension

Portal hypertension (PH) is still a challenging clinical condition due to its silent manifestations in the early stage and needs to be measured accurately for early detection. Hepatic vein pressure gradient measurement has been considered as the gold standard measurement for PH; however, it needs special skill, experience, and high expertise. Recently, there has been an innovative development in using endoscopic ultrasound (EUS) for the diagnosis and management of liver diseases, including portal pressure measurement, which is commonly known as EUS-guided portal pressure gradient (EUS-PPG) measurement. EUS-PPG measurement can be performed concomitantly with EUS evaluation for deep esophageal varices, EUS-guided liver biopsy, and EUS-guided cyanoacrylate injection. However, there are still major issues, such as different etiologies of liver disease, procedural training, expertise, availability, and cost-effectiveness in several situations with regard to the standard management.

Agreement between Wedged Hepatic Venous Pressure and Portal Pressure in Hepatic Sinusoidal Obstruction Syndrome

Background: Wedge hepatic vein pressure (WHVP) accurately estimates the portal pressure (PP) in chronic sinusoidal portal hypertension patients. Whether this applies to patients with acute portal hypertension due to hepatic sinusoidal obstruction syndrome (HSOS) is unclear. Our aim was to assess the agreement between WHVP and PP in patients with HSOS by comparing them to decompensated cirrhosis patients. Methods: From December 2013 to December 2021, patients with pyrrolidine alkaloid-induced HSOS (PA-HSOS) receiving hepatic venous pressure gradient (HVPG) measurement and transjugular intrahepatic portosystem shunt (TIPS) were retrospectively collected and matched with those of patients with virus- or alcohol-related cirrhosis as a cirrhosis group. Pearson’s correlation (R), intraclass correlation coefficient (ICC), scatter plots, and the Bland−Altman method were performed for agreement evaluation. Results: A total of 64 patients were analyzed (30 PA-HSOS and 34 cirrhosis groups). The correlation between WHVP and PP was moderate in the PA-HSOS group (R: 0.58, p = 0.001; ICC: 0.68, p = 0.002) but good in the cirrhosis group (R: 0.81, p < 0.001; ICC: 0.90, p < 0.001). The percentage of patients with inconsistent WHVP and PP in the two groups was 13 (43.3%) and 15 (26.5%) (p = 0.156), respectively, and an overestimation of PP was more common in the PA-HSOS group (33.3% vs. 2.9%, p = 0.004). HVPG and portal pressure gradient (PPG) consistency was poor in both groups (R: 0.51 vs. 0.26; ICC: 0.65 vs. 0.41; p < 0.05). Conclusions: WHVP in patients with PA-HSOS did not estimate PP as accurately as in patients with virus- or alcohol-related cirrhosis, which was mainly due to PP overestimation.

Correlation of pressure gradient in three hepatic veins with portal pressure gradient

BACKGROUND

The liver is one of the most important organs in the human body, with functions such as detoxification, digestion, and blood coagulation. In terms of vascular anatomy, the liver is divided into the left and the right liver by the main portal vein, and there are three hepatic efferent veins (right, middle, and left) and two portal branches. Patients with impaired liver function have increased intrahepatic vascular resistance and splanchnic vasodilation, which may lead to an increase in the portal pressure gradient (PPG) and cause portal hypertension (PHT). In order to measure the increased pressure gradient of portal vein, the hepatic venous pressure gradient (HVPG) can be measured to reflect it in clinical practice. The accuracy of PPG measurements is directly related to patient prognosis.

AIM

To analyze the correlation between HVPG of three hepatic veins and PPG in patients with PHT.

METHODS

From January 2017 to December 2019, 102 patients with PHT who met the inclusion criteria were evaluated during the transjugular intrahepatic portosystemic shunt procedure and analyzed.

RESULTS

The mean HVPG of the middle hepatic vein was 17.47 ± 10.25 mmHg, and the mean HVPG of the right and left hepatic veins was 16.34 ± 7.60 and 16.52 ± 8.15 mmHg, respectively. The average PPG was 26.03 ± 9.24 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.15 and 0.02 (P = 0.164); 0.25 and 0.05 (P = 0.013); and 0.14 and 0.02 (P = 0.013), respectively. The mean wedged hepatic vein/venous pressure (WHVP) of the middle and left hepatic veins was similar at 29.71 ± 12.48 and 29.1 ± 10.91 mmHg, respectively, and the mean WHVP of the right hepatic vein was slightly lower at 28.01 ± 8.95 mmHg. The mean portal vein pressure was 34.11 ± 8.56 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.26 and 0.07 (P = 0.009); 0.38 and 0.15 (P < 0.001); and 0.26 and 0.07 (P = 0.008), respectively. The average free hepatic venous pressure (FHVP) of the right hepatic vein was lowest at 11.67 ± 5.34 mmHg, and the average FHVP of the middle and left hepatic veins was slightly higher at 12.19 ± 4.88 and 11.67 ± 5.34 mmHg, respectively. The average inferior vena cava pressure was 8.27 ± 4.04 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.30 and 0.09 (P = 0.002); 0.18 and 0.03 (P = 0.078); and 0.16 and 0.03 (P = 0.111), respectively.

CONCLUSION

Measurement of the middle hepatic vein HVPG could better represent PPG. Considering the high success rate of clinical measurement of the right hepatic vein, it can be the second choice.

Hepatic venous-portal gradient (HVPG) measurement: pearls and pitfalls

Hepatic venous pressure gradient (HVPG) is the gold-standard for measurement of portal hypertension, a common cause for life-threatening conditions such as variceal bleeding and hepatic encephalopathy. HVPG also plays a crucial role in risk stratification, treatment selection and assessment of treatment response. Thus recognition of common pitfalls and unusual hepatic venous conditions is crucial. This article aims to provide a radiographical and clinical guide to HVPG with representative clinical cases.

Per-rectal portal scintigraphy as an alternative measure of hepatic venous pressure gradient in chronic liver disease: A preliminary report

AIM

Hepatic venous pressure gradient (HVPG) measurement is a gold standard for the diagnosis of portal hypertension but can be invasive and difficult to conduct. Per-rectal portal scintigraphy (PRPS) can estimate portal haemodynamics noninvasively. However, no report to date has examined the association between HVPG and PRPS in patients with chronic liver disease, including cirrhosis.

METHODS

This single-centre study included a total of 21 patients with chronic liver disease who underwent HVPG measurement and PRPS. For PRPS, the transit times from injection of the radiotracer to its inflow into the liver (TTL) and heart (TTH) were set and the time difference between TTL and TTH (TDLH) was calculated, while the shunt index (SI) was measured.

RESULTS

Cirrhosis was observed in 18 cases (86%), and the median HVPG was 13 mmHg. HVPG (p = 0.028), TTL (p = 0.018), TDLH (p = 0.003) and SI (p = 0.033) were higher in patients with oesophageal varices (EV). Considering the diagnostic ability for EV, the area under the curve was 0.88 for TDLH and 0.80 for HVPG. TDLH was significantly correlated with the risk of EV rupture (p = 0.004).

CONCLUSION

Patients with chronic liver disease should undergo upper gastrointestinal endoscopy when the TDLH is high.

Application of Hepatic Transit Time and Shear Wave Velocity in Assessing Portal Pressure in Patients with Cirrhotic Portal Hypertension

The aim of the study described here was to explore the value of hepatic transit time (HTT) and shear wave velocity (SWV) in diagnosing cirrhotic portal hypertension. Fifty-seven patients had undergone esophagogastric varicose vein embolization (group OBS) and 50 healthy controls (group CON) were retrospectively compared with respect to HTT (arterial-hepatic vein [HA-HVTT], portal vein-hepatic vein [PV-HVTT], liver parenchyma-hepatic vein [PA-HVTT]) and SWV to analyze their efficacy in diagnosing cirrhotic portal hypertension. The correlations between SWV/HTT and free portal pressure (FPP) in group OBS were also analyzed. Compared with group CON, group OBS had a shorter HTT and faster SWV. The area under the curve (AUC) of PV-HVTT (0.93) was higher than those of HA-HVTT (0.75) and PA-HVTT (0.64), the AUCs of PV-HVTT (0.93, threshold 7.9 s) and SWV (0.91, threshold 2.0 cm/s) did not statistically differ (z = 0.35, p = 0.73). HTT and FPP in group OBS had a negative correlation. In conclusion, HTT and SWV can be used to diagnose cirrhotic portal hypertension without difference in diagnostic efficacy, and HTT is more meaningful for assessing the changes in portal pressure.

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.

Liver Stiffness: A Significant Relationship with the Waveform Pattern in the Hepatic Vein

The aim of this prospective study was to assess the relationship between liver stiffness and hepatic vein waveform patterns in 42 patients with chronic hepatitis and 55 with cirrhosis. Liver stiffness measurement (LSM) values (FibroScan, Echosens, Paris, France) were significantly lower in the triphasic pattern group (11.3 ± 8.4 kPa) than in the monophasic pattern (32.5 ± 23.5 kPa, p = 0.001) and biphasic pattern (25.6 ± 18.1 kPa, p = 0.001) groups, indicating no significant relationship with portal pressure. The ability to diagnose cirrhosis represented by the highest area under the receiver operating characteristic curve was 0.921 (83.6% sensitivity, 90.5% specificity, best cutoff value: 16.9 kPa) by LSM and 1.000 (best cutoff value: 19.4 kPa) by LSM combined with the monophasic pattern. This study revealed a close linkage between liver stiffness and hepatic vein waveform findings, resulting in a better understanding of hepatic vein hemodynamics and wider application of its analysis.

Potential stagnation in the splanchnic hemodynamics demonstrated by the dynamic microbubbles in chronic liver disease

BACKGROUND AND AIM

Impaired splanchnic hemodynamics are well-documented phenomena in cirrhosis. However, comprehensive hemodynamic features from the superior mesenteric artery (SMA) to the superior mesenteric vein (SMV) via intestinal capillaries have not been studied. The aim was to examine splanchnic hemodynamics and their relationship with clinical presentations.

METHODS

Contrast-enhanced ultrasound was performed for both the SMA and SMV under fasting conditions and postprandially following ingestion of a liquid diet. The microbubble traveling time (MTT) was determined as the difference between the contrast onset in the SMA and SMV, indicating the time required for microbubble transit through the splanchnic circulation.

RESULTS

There were 192 subjects for fasting conditions (81 cirrhosis, 72 chronic hepatitis, 39 healthy controls), and 74/192 for postprandial conditions (44 cirrhosis, 11 chronic hepatitis, 19 healthy controls). The MTT (fasting; postprandial) was significantly longer in cirrhosis (7.7 ± 2.9 s; 7.0 ± 0.3 s) than in controls (5.4 ± 2.3 s, P < 0.001; 3.9 ± 0.9 s, P<0.001) and chronic hepatitis (6.3 ± 2.5 s, P=0.007; 5.1 ± 1.4 s, P=0.013). The MTT ratio (postprandial/fasting) showed disease-related changes: 0.75 ± 0.20 in controls, 0.78 ± 0.15 in chronic hepatitis, and 1.00 ± 0.28 in cirrhosis (P=0.003, vs controls; P=0.036, vs chronic hepatitis).

CONCLUSIONS

The real-time observation of traveling microbubble on the sonogram revealed a prolonged transit with a weak postprandial response in the intestinal circulation, suggesting better understanding of underlying pathophysiology of splanchnic hemodynamics in chronic liver disease.

Invasive and non-invasive techniques for detecting portal hypertension and predicting variceal bleeding in cirrhosis: a review

Portal hypertension is a severe syndrome that may derive from pre-sinusoidal, sinusoidal, and post-sinusoidal causes. As a consequence, several complications (i.e. ascites, oesophageal varices) may develop. In sinusoidal portal hypertension, hepatic venous pressure gradient (HVPG) is a reliable method for defining the grade of portal pressure, establishing the effectiveness of the treatment, and predicting the occurrence of complications; however, some questions exist regarding its ability to discriminate bleeding from non-bleeding varices in cirrhotic patients. Other imaging techniques (transient elastography, endoscopy, endosonography, and duplex Doppler sonography) for assessing causes and complications of portal hypertensive syndrome are available and may be valuable for the management of these patients. In this review, we evaluate invasive and non-invasive techniques currently employed to obtain a clinical prediction of deadly complications, such as variceal bleeding in patients affected by sinusoidal portal hypertension, in order to create a diagnostic algorithm to manage them. Again, HVPG appears to be the reference standard to evaluate portal hypertension and monitor the response to treatment, but its ability to predict several complications and support management decisions might be further improved through the diagnostic combination with other imaging techniques.

Hepatic and splenic stiffness augmentation assessed with MR elastography in an in vivo porcine portal hypertension model

PURPOSE

To investigate the influence of portal pressure on the shear stiffness of the liver and spleen in a well-controlled in vivo porcine model with magnetic resonance elastography (MRE). A significant correlation between portal pressure and tissue stiffness could be used to noninvasively assess increased portal venous pressure (portal hypertension), which is a frequent clinical condition caused by cirrhosis of the liver and is responsible for the development of many lethal complications.

MATERIALS AND METHODS

During multiple intraarterial infusions of Dextran-40 in three adult domestic pigs in vivo, 3D abdominal MRE was performed with left ventricle and portal catheters measuring blood pressure simultaneously. Least-squares linear regressions were used to analyze the relationship between tissue stiffness and portal pressure.

RESULTS

Liver and spleen stiffness have a dynamic component that increases significantly following an increase in portal or left ventricular pressure. Correlation coefficients with the linear regressions between stiffness and pressure exceeded 0.8 in most cases.

CONCLUSION

The observed stiffness-pressure relationship of the liver and spleen could provide a promising noninvasive method for assessing portal pressure. Using MRE to study the tissue mechanics associated with portal pressure may provide new insights into the natural history and pathophysiology of hepatic diseases and may have significant diagnostic value in the future.

The risk factors for bleeding of fundal varices in patients with liver cirrhosis

Background/Aims

The relationship between portal hemodynamics and fundal varices has not been well documented. The purpose of this study was to understand the pathophysiology of fundal varices and to investigate bleeding risk factors related to the presence of spontaneous portosystemic shunts, and to examine the hepatic venous pressure gradient (HVPG) between fundal varices and other varices.

Methods

In total, 85 patients with cirrhosis who underwent HVPG and gastroscopic examination between July 2009 and March 2011 were included in this study. The interrelationship between HVPG and the types of varices or the presence of spontaneous portosystemic shunts was studied.

Results

There was no significant difference in the HVPG between fundal varices (n=12) and esophageal varices and gastroesophageal varices type 1 (GOV1) groups (n=73) (17.1±7.7 mm Hg vs 19.7±5.3 mm Hg). Additionally, there was no significant difference in the HVPG between varices with spontaneous portosystemic shunts (n=28) and varices without these shunts (n=57) (18.3±5.8 mm Hg vs 17.0±8.1 mm Hg). Spontaneous portosystemic shunts increased in fundal varices compared with esophageal varices and GOV1 (8/12 patients [66.7%] vs 20/73 patients [27.4%]; p=0.016).

Conclusions

Fundal varices had a high prevalence of spontaneous portosystemic shunts compared with other varices. However, the portal pressure in fundal varices was not different from the pressure in esophageal varices and GOV1.

Improving survival in decompensated cirrhosis

Mortality in cirrhosis is consequent of decompensation, only treatment being timely liver transplantation. Organ allocation is prioritized for the sickest patients based on Model for End Stage Liver Disease (MELD) score. In order to improve survival in patients with high MELD score it is imperative to preserve them in suitable condition till transplantation. Here we examine means to prolong life in high MELD score patients till a suitable liver is available. We specially emphasize protection of airways by avoidance of sedatives, avoidance of Bilevel Positive Airway Pressure, elective intubation in grade III or higher encephalopathy, maintaining a low threshold for intubation with lesser grades of encephalopathy when undergoing upper endoscopy or colonoscopy as pre transplant evaluation or transferring patient to a transplant center. Consider post-pyloric tube feeding in encephalopathy to maintain muscle mass and minimize risk of aspiration. In non intubated and well controlled encephalopathy, frequent physical mobility by active and passive exercises are recommended. When renal replacement therapy is needed, night-time Continuous Veno-Venous Hemodialysis may be useful in keeping the daytime free for mobility. Sparing and judicious use of steroids needs to be borne in mind in treatment of ARDS and acute hepatitis from alcohol or autoimmune process.

Value of hepatic venous pressure gradient measurement before liver resection for hepatocellular carcinoma

BACKGROUND

Portal hypertension associated with liver cirrhosis increases the risk of postoperative complications after liver resection for hepatocellular carcinoma (HCC). This study assessed the role of preoperative hepatic venous pressure gradient (HVPG) assessment in identifying portal hypertension.

METHODS

All patients who underwent liver resection for HCC between January 2000 and December 2009 at the Department of General Surgery, Medical University Vienna, were analysed retrospectively. HVPG was assessed prospectively in a subset of patients before liver resection. The influence of this assessment on postoperative complications was investigated.

RESULTS

A total of 132 patients were enrolled, of whom 39 underwent HVPG measurement. Mean(s.d.) HVPG was 6·4(3·0) and 4·3(1·4) mmHg in patients with and without postoperative complications respectively (P = 0·028). Complication rates differed significantly at a cut-off HVPG value of 5 mmHg: 11 of 21 patients with a gradient of 1-5 mmHg developed complications versus 12 of 14 patients with a higher value (P = 0·045). HVPG exceeding 5 mmHg was associated with worse liver fibrosis (P = 0·004), higher rates of postoperative liver dysfunction (5 of 13 versus 1 of 18; P = 0·022) and ascites (7 of 14 versus 3 of 21; P = 0·022), and a longer hospital stay (median (range) 11 (7-26) versus 8 (4-20) days; P = 0·034). Overall postoperative morbidity did not differ between patients who had preoperative HVPG assessment and those who did not (P = 0·142).

CONCLUSION

Preoperative HVPG assessment predicted liver fibrosis and postoperative complications.

[Recent advances in diagnosis of portal hypertension]

Complications of portal hypertension are major concerns in liver cirrhosis and significant morbidity and mortality mainly because of variceal bleeding, ascites, bacterial infections, hepatic encephalopathy, and hepatorenal syndrome. Various modalities in the diagnosis of portal hypertension are reviewed. The measurement of hepatic venous pressure gradient (HVPG) is a simple, invasive, reproducible method and regarded as the gold standard for the diagnosis and staging of portal hypertension. Other tests such as transient elastography, per-endoscopic variceal pressure measurement, endoscopic ultrasonography, and Doppler ultrasonography may be complementary and promising.

Duplex Doppler ultrasound examination of the portal venous system: an emerging novel technique for the estimation of portal vein pressure

PURPOSE

Measurement of portal venous pressure in patients with portal hypertension is important to assess efficacy of beta blockers in patients with esophageal varices. Currently, the gold standard for measurement of portal venous pressure is the estimation of hepatic venous pressure gradient (HVPG). Being an invasive technique, serial measurements of HVPG are not feasible in clinical practice. In this respect, duplex Doppler ultrasound (DDUS) examination is an upcoming non-invasive technique for the estimation of portal venous and splanchnic hemodynamics. The aim of the present review is to analyze the current literature focusing on how the two techniques compare to each other in terms of assessing the portal pressure and assessing pitfalls in the current technique.

RESULTS

Duplex Doppler ultrasound (DDUS) currently has limitations in measuring the portal pressure in a non-invasive way. Hemodynamic venous and arterial indices measured on DDUS correlate with the HVPG. The technique has been refined, however, there is no uniform surrogate marker that can be used in clinical practice.

CONCLUSIONS

More studies are needed in order to remove the shortcomings in the current technique. The target is to be able to measure the actual portal pressure or at least derive an ideal venous or arterial hemodynamic surrogate marker having close correlation with the HVPG.

Correlation of D-xylose absorption rate with portal pressure in rats with portal hypertension

AIM: To evaluate the dynamic changes in D-xylose absorption rate during the progression of portal hypertension to find a noninvasive and practical method to evaluate portal pressure.

METHODS: Eighty male Sprague-Dawley rats, weighing 180-220 g, were randomly divided into two groups: normal control group (n = 5) and model group (n = 75). Fifty-five model rats were randomly divided into 11 subgroups (n = 5). The normal control group was given normal drinking water, while the model group was given 0.03% thioacetamide (TAA) for 5 weeks and 0.04% TAA for another 5 weeks. The pathological changes in the liver and portal pressure were monitored until 6 weeks after withdrawal of TAA. The D-xylose content of the urine and portal pressure were determined at weeks 2, 4, 6, 8, 10, 11, 12, 13, 14, 15, and 16, respectively. The correlation between D-xylose absorption rate and portal pressure was analyzed.

RESULTS: At week 8, apparent fibrous septum hyperplasia, disorganized hepatic lobule architecture, and even pseudolobules were observed. Meanwhile, portal vein pressure and D-xylose absorption rate began to show significant changes. The D-xylose absorption rate is inversely correlated with portal vein pressure (P < 0.01). The correlation coefficient is -0.697, and the linear equation is: y = -0.01x + 0.2791.

CONCLUSION: D-xylose absorption rate can reflect the changes in hepatic portal pressure and can be used to predict portal hypertension pressure and evaluate therapeutic effects in clinical practice.