Occlusive hepatic venous catheterization in the study of the normal liver, cirrhosis of the liver and noncirrhotic portal hypertension

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.

Methods for assessing portal hypertension

Many researchers and clinicians have taken the value of hepatic venous pressure gradient (HVPG) as an essential prognostic factor in subjects with chronic liver diseases. HVPG ≥ 10 mmHg indicates the presence of clinically significant portal hypertension, the main predictor of the risk of variceal bleeding, hepatic decompensation, and mortality. However, HVPG measurement is invasive and requires high expertise, so its routine use outside tertiary care centers or clinical trials is limited. Clinically significant portal hypertension also might be detected using non-invasive options such as ultrasonography, elastography, magnetic resonance imaging, and indices derived from laboratory parameters. Our review aims to present the feasibility and applicability of HVPG in modern clinical practice in patients with liver cirrhosis, including invasive and non-invasive methods, based on literary sources from the MEDLINE database.

Endovascular Assessment of Liver Hemodynamics in Patients with Cirrhosis Complicated by Portal Hypertension

The hepatic venous pressure gradient (HVPG) is currently considered the gold standard to assess portal hypertension (PH) in patients with cirrhosis. A meticulous technique is important to achieve accurate and reproducible results, and values obtained during measurement are applied in risk stratification of patients with PH, allocating treatment options, monitoring follow-up, and deciding management options in surgical patients. The use of portosystemic pressure gradients in patients undergoing placement of transjugular intrahepatic portosystemic shunts has been studied extensively and has great influence on decisions on shunt diameter. The purpose of this study was to describe the recommended technique to measure HVPG and portosystemic pressure gradient and to review the existing literature describing the importance of these hemodynamic measurements in clinical practice.

Agreement between wedged hepatic venous pressure and portal pressure in non-alcoholic steatohepatitis-related cirrhosis

BACKGROUND & AIMS

Wedge hepatic vein pressure (WHVP) accurately estimates portal pressure (PP) in alcohol- or viral hepatitis-related cirrhosis. Whether this also holds true in cirrhosis caused by non-alcoholic steatohepatitis (NASH) is unknown. We aimed to evaluate the agreement between WHVP and PP in patients with NASH cirrhosis in comparison to patients with alcohol- or HCV-related cirrhosis.

METHODS

All consecutive patients with NASH cirrhosis treated with a transjugular intrahepatic portosystemic shunt (TIPS) in 3 European centres were included (NASH group; n = 40) and matched with 2 controls (1 with alcohol-related and 1 with HCV-related cirrhosis) treated with TIPS contemporaneously (control group; n = 80). Agreement was assessed by Pearson's correlation (R), intra-class correlation coefficient (ICC), and Bland-Altman method. Disagreement between WHVP and PP occurred when both pressures differed by >10% of PP value. A binary logistic regression analysis was performed to identify factors associated with this disagreement.

RESULTS

Correlation between WHVP and PP was excellent in the control group (R 0.92; p <0.001; ICC 0.96; p <0.001) and moderate in the NASH group (R 0.61; p <0.001; ICC 0.74; p <0.001). Disagreement between WHVP and PP was more frequent in the NASH group (37.5% vs. 14%; p = 0.003) and was mainly because of PP underestimation. In uni- and multivariate analyses, only NASH aetiology was associated with disagreement between WHVP and PP (odds ratio 4.03; 95% CI 1.60-10.15; p = 0.003).

CONCLUSIONS

In patients with decompensated NASH cirrhosis, WHVP does not estimate PP as accurately as in patients with alcohol- or HCV-related cirrhosis, mainly because of PP underestimation. Further studies aimed to assess this agreement in patients with compensated NASH cirrhosis are needed.

LAY SUMMARY

Portal pressure is usually assessed by measuring wedge hepatic vein pressure because of solid evidence demonstrating their excellent agreement in alcohol- and viral hepatitis-related cirrhosis. Our results show that in patients with decompensated cirrhosis caused by non-alcoholic steatohepatitis, wedge hepatic vein pressure estimates portal pressure with less accuracy than in patients with other aetiologies of cirrhosis, mainly because of portal pressure underestimation.

Application of Hepatic Venous Pressure Gradient to Predict Prognosis in Cirrhotic Patients with a Low Model for End-Stage Liver Disease Score

Background/aim: We aimed to derive a model representing the dynamic status of cirrhosis and to discriminate patients with poor prognosis even if the Model for End-Stage Liver Disease (MELD) score is low. Methods: This study retrospectively enrolled 700 cirrhotic patients with a MELD score of less than 20 who underwent hepatic venous pressure gradient (HVPG) measurement. A model named H6C score (= HVPG + 6 × CTP score) to predict overall survival was derived and internal and external validations were conducted with the derivation and validation cohorts. Results: The H6C score using the HVPG was developed based on a multivariate Cox regression analysis. The H6C score showed a great predictive power for overall survival with a time-dependent AUC of 0.733, which was superior to that of a MELD of 0.602. In patients with viral etiology, the performance of the H6C score was much improved with a time-dependent AUC of 0.850 and was consistently superior to that of the MELD (0.748). Patients with an H6C score below 45 demonstrated an excellent overall survival with a 5-year survival rate of 91.5%. Whereas, patients with an H6C score above 64 showed a dismal prognosis with a 5-year survival rate of 51.1%. The performance of the H6C score was further verified to be excellent in the validation cohort. Conclusion: This new model using the HVPG provides an excellent predictive power in cirrhotic patients, especially with viral etiology. In patients with H6C above 64, it would be wise to consider early liver transplantation to positively impact long-term survival, even when the MELD score is low.

Managing portal hypertension in patients with liver cirrhosis

Portal hypertension is one cause and a part of a dynamic process triggered by chronic liver disease, mostly induced by alcohol or incorrect nutrition and less often by viral infections and autoimmune or genetic disease. Adequate staging - continuously modified by current knowledge - should guide the prevention and treatment of portal hypertension with defined endpoints. The main goals are interruption of etiology and prevention of complications followed, if necessary, by treatment of these. For the past few decades, shunts, mostly as intrahepatic stent bypass between portal and hepatic vein branches, have played an important role in the prevention of recurrent bleeding and ascites formation, although their impact on survival remains ambiguous. Systemic drugs, such as non-selective beta-blockers, statins, or antibiotics, reduce portal hypertension by decreasing intrahepatic resistance or portal tributary blood flow or by blunting inflammatory stimuli inside and outside the liver. Here, the interactions among the gut, liver, and brain are increasingly examined for new therapeutic options. There is no general panacea. The interruption of initiating factors is key. If not possible or if not possible in a timely manner, combined approaches should receive more attention before considering liver transplantation.

Pathophysiology of Portal Hypertension

The bases of our current knowledge on the physiology of the hepatic portal system are largely owed to the work of three pioneering vascular researchers from the sixteenth and the seventeenth centuries: A. Vesalius, W. Harvey, and F. Glisson. Vesalius is referred to as the founder of modern human anatomy, and in his influential book, De humani corporis fabrica libri septem, he elaborated the first anatomical atlas of the hepatic portal venous system (Vesalius 2013). Sir William Harvey laid the foundations of modern cardiovascular research with his Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Harvey 1931) in which he established the nature of blood circulation. Finally, F. Glisson characterized the gastrointestinal-hepatic vascular system (Child 1955). These physiological descriptions were later complemented with clinical observations. In the eighteenth and nineteenth centuries, Morgagni, Puckelt, Cruveilhier, and Osler were the first to make the connection between common hepatic complications – ascites, splenomegaly, and gastrointestinal bleeding – and obstruction of the portal system (Sandblom 1993). These were the foundations that allowed Gilbert, Villaret, and Thompson to establish an early definition of portal hypertension at the beginning of the twentieth century. In this period, Thompson performed the first direct measurement of portal pressure by laparotomy in some patients (Gilbert and Villaret 1906; Thompson et al. 1937). Considering all these milestones, and paraphrasing Sir Isaac Newton, if hepatologists have seen further, it is by standing on the shoulders of giants.

Nowadays, our understanding of the pathogenesis of portal hypertension has largely improved thanks to the progress in preclinical and clinical research. However, this field is ever-changing and hepatologists are continually identifying novel pathological mechanisms and developing new therapeutic strategies for this clinical condition. Hence, the aim of this chapter is to summarize the current knowledge about this clinical condition.

Quantitative modeling of the physiology of ascites in portal hypertension

Although the factors involved in cirrhotic ascites have been studied for a century, a number of observations are not understood, including the action of diuretics in the treatment of ascites and the ability of the plasma-ascitic albumin gradient to diagnose portal hypertension. This communication presents an explanation of ascites based solely on pathophysiological alterations within the peritoneal cavity. A quantitative model is described based on experimental vascular and intraperitoneal pressures, lymph flow, and peritoneal space compliance. The model's predictions accurately mimic clinical observations in ascites, including the magnitude and time course of changes observed following paracentesis or diuretic therapy.

Should we routinely measure portal pressure in patients with cirrhosis, using hepatic venous pressure gradient (HVPG) as guidance for prophylaxis and treatment of bleeding and re-bleeding? Yes!

Portal hypertension is key to the natural history of cirrhosis. The standard way to assess portal hypertension is the hepatic venous pressure gradient (HVPG). HVPG has been convincingly shown to be a strong predictor of variceal bleeding and survival. In addition, it has been shown to predict other portal hypertension-related clinical events, to include fluid retention and hepatic encephalopathy. Finally, HVPG is the only suitable tool to assess the response of portal hypertension to medical treatment. Thus, although not necessarily easy to measure, HVPG provides the clinician with information which is prognostically crucial and otherwise unobtainable.

Liver diseases in heart failure

Heart failure (HF) is a growing public health concern as a consequence of the ageing of the population and the improved survival of patients with HF. HF is defined as impaired organ perfusion and/or high filling pressure. It is a systemic and chronic disease and as such involves many organs, not least the liver and kidney. The complex vascular system of the liver and its high metabolic activity render it vulnerable to circulation disturbances and trigger many molecular and haemodynamic changes in patients. There are many studies describing the impact of liver disease on patient outcomes. Hepatic dysfunction is commonly seen in HF patients and is closely correlated with a poor outcome. Knowledge about the mechanisms and impacts of liver disease in HF helps us to know the stage of the disease and treat it properly. Moreover, many drugs and toxins that are metabolised in the liver and contribute to drug interactions should also be taken into account when prescribing medication for HF patients. In light of the above-mentioned points, the authors have compiled this review on congestive hepatopathy with the aim of providing physicians and cardiologists with a succinct and useful guide on the role of the liver in HF.

[Relationship between portal pressure gradient and ascites in cirrhotic patients]

CONTEXT

Portal hypertension plays an important role in the pathogenesis of ascites.

OBJECTIVES

To evaluate the hepatic venous pressure gradient and the presence of ascites in cirrhotic patients.

METHODS

Eighty-three patients with cirrhosis were evaluated. All of the patients were submitted to ultrasonography to identify ascites and to a hepatic hemodynamic investigation to determine the hepatic venous pressure gradient.

RESULTS

In the population evaluated, ascites was observed in 70 patients (84.3%), and the mean hepatic venous pressure gradient was 15.26 +/- 6.46 mm Hg. There was no statistically significant difference (P = 0.061) between the means of hepatic venous pressure gradient in patients with (14.70 +/- 6.43 mm Hg) and without ascites (18.64 +/- 5.78 mm Hg). When using a cut-off point of 8 mm Hg in order to assess the risk of developing ascites, patients with hepatic venous pressure gradient above 8 mm Hg were found to have a relative risk of 0.876 (CI = 0.74-1.03), (P = 0.446) of progressing to ascites.

CONCLUSIONS

The pressure level of 8 mm Hg, as determined by the hepatic venous pressure gradient, does not define the presence or absence of ascites in the cirrhotic patient, and in view of the similarity between mean pressures in patients with or without peritoneal effusion, it is impossible to define a cut-off point for the emergence of such complication.

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.

Correlação entre a contagem de plaquetas no sangue e o gradiente de pressão venosa hepática em pacientes cirróticos

RACIONAL: A medida do gradiente de pressão venosa hepática é o método mais utilizado para a avaliação da pressão portal. Mais recentemente, a contagem de plaquetas no sangue tem sido apontada como um marcador não-invasivo da presença de hipertensão portal. OBJETIVO: Correlacionar a contagem de plaquetas com os valores do gradiente de pressão venosa hepática em uma população de pacientes cirróticos. PACIENTES E MÉTODOS: Foram estudados 83 pacientes com hepatopatia crônica que realizaram estudo hemodinâmico hepático, em período de 6 anos. Os pacientes foram divididos em grupos conforme a classificação de Child-Pugh e todos realizaram endoscopia digestiva alta para constatar a presença de varizes de esôfago, assim como tiveram a contagem sérica de plaquetas determinada. RESULTADOS: O número de plaquetas variou entre 45.000/mm³ e 389.000/mm³, com média 104.099 e desvio-padrão 58.776. O gradiente de pressão venosa apresentou média igual a 15,2 mm Hg e desvio-padrão igual a 6,4 mm Hg, variando de 1 a 29 mm Hg. Realizou-se regressão linear simples para verificar a correlação entre o gradiente de pressão venosa e o número de plaquetas, o que permitiu constatar fraca correlação entre ambos. Embora se tenha observado menor número de plaquetas, à medida que o calibre das varizes aumentava e nos pacientes com maior grau de disfunção hepatocelular - medida pela classificação de Child-Pugh - não se encontrou significância estatística. CONCLUSÃO: A despeito de não haver demonstrado correlação estatística entre o número de plaquetas com o gradiente de pressão venosa hepática e o grau de disfunção hepatocelular, pelas tendências observadas, acredita-se que ambos os fatores podem estar implicados na patogenia da plaquetopenia em pacientes cirróticos.

A double-blind randomized controlled trial of colchicine in patients with hepatitis B virus-related postnecrotic cirrhosis

The preliminary results of a prospective double-blind controlled trial of colchicine in 100 patients with hepatitis B virus-related cirrhosis are reported. The patients, 94 males and 6 females, aged 32-80, were assigned to receive either 1 mg of colchicine or an identical placebo orally on a daily basis. The duration of the follow up ranged from 15 to 51 months (median 26 months). Seventy percent had histological proof of cirrhosis. On entry, 80 patients were in Child-Pugh class A, 19 were in class B, and one was in class C. Compared to the placebo group, there was no improvement in the colchicine group after a 24-month follow up in any of the biochemistry data, for example, serum albumin, alkaline phosphatase, alanine and aspartate aminotransferase, bilirubin, and prothrombin time. The difference in the cumulative survival rates at 51 months did not reach statistical significance (p = 0.8) in either group. There was no histological improvement in 30 patients who were willing to undergo repeated liver biopsies. No trend toward improvement of the hepatic pressure gradient was observed in these patients. The serum levels of aminopropeptide of type III procollagen increased significantly in patients in both groups after 24 months of therapy (1.07 +/- 0.06 vs. 1.36 +/- 0.06 U/ml in the colchicine group, 0.93 +/- 0.09 vs. 1.25 +/- 0.07 U/ml in the placebo group; p < 0.05). In addition, neither the clinical deterioration of cirrhosis nor death was prevented in patients receiving colchicine therapy. This report indicates that colchicine has no effect in the treatment of HBV-related postnecrotic cirrhosis.

Significance of corrected sinusoidal pressure (CSP) in patients with cirrhosis and portal hypertension

The relationship between the degree of portal hypertension measured by the corrected sinusoidal pressure (CSP), the size of varices graded endoscopically, the risk of variceal hemorrhage and the prognosis following portal decompression were studied in 32 patients with cirrhosis demonstrated by examination of a biopsy specimen. The CSP was no different in patients with large-sized versus small or moderate-sized varices. CSP was of no discriminant value in patients with bleeding versus nonbleeding varices and, furthermore, was of no prognostic value in patients requiring operative portal decompression. The risk of variceal bleeding was highest in patients with large-sized varices. We conclude, therefore, that CSP measurements have little if any therapeutic or prognostic importance in cirrhotic patients with portal hypertension or gastrointestinal bleeding. CSP may, however, be useful in establishing extrahepatic or presinusoidal causes of portal hypertension.

Wedged hepatic venous pressure in congential heart disease

Seventy cases of congential heart disease including the most frequent types were studied, and wedge hepatic venous pressure (WHVP) was measured in each. The mean pressure was determined in the "jammed position" and in the free hepatic veins, inferior vena cava, and low right atrium. The average mean WHVP was 7.0 mm Hg, 5.0 in inferior vena cava, and 3.4 in the right atrium. A direct relationship was found between wedge hepatic venous pressure of the inferior vena cava and the low right atrium, but not other parameters. Ten patients had a mean pressure above 10 mm Hg. We believe that in many circumstances in patients with congenital heart disease, liver function may be abnormal and high values of wedge hepatic venous pressure may also be found.

Treatment of Budd-Chiari syndrome by side-to-side portacaval shunt: experimental and clinical results

The Budd-Chiari syndrome caused by occlusion of the major hepatic veins, often of unknown etiology, is typically characterized by massive ascites, hepatomegaly and abdominal pain due to intense congestion of the liver. The outcome has almost always been fatal. This report describes an evaluation of side-to-side portacaval shunt in dogs with experimental Budd-Chiari syndrome and in six patients with hepatic vein thrombosis. In the animal studies, side-to-side portacaval shunt was very effective in relieving massive ascites, hepatomegaly, hepatic congestion and portal hypertension produced by ligation of the hepatic veins. Only one of 24 dogs with side-to-side anastomosis reformed ascites, 67% of the animals survived until the study was concluded after one year, and liver biopsies showed reversal of the severe pathologic abnormalities. In contrast, all 20 control dogs subjected to a sham laparotomy, and all 20 dogs that underwent end-to-side portacaval shunt reformed massive ascites and died within six months with continued hepatic congestion and necrosis. All six patients with the Budd-Chiari syndrome due to hepatic vein occlusion had massive ascites (4.4-15.9 l), hepatomegaly, abdominal pain and disturbed liver function. In all six, angiography demonstrated occlusion of the hepatic veins with a patent inferior vena cava (IVC) and a normal IVC pressure, and liver biopsy showed intense centrilobular congestion and necrosis. The most valuable diagnostic study was angiography of the IVC and hepatic veins with pressure measurements. Side-to-side portacaval shunt was performed from four to 14 weeks after the onset of symptoms, and produced dramatic and sustained relief of ascites in five of the six patients during follow-up periods of from eight months to seven years. Liver function returned to normal, hepatosplenomegaly disappeared, none of the survivors developed portal-systemic encephalopathy, and follow-up liver biopsies showed disappearance of congestion and necrosis, but mild to moderate fibrosis. One patient died following an emergency IVC thrombectomy and portacaval shunt, which was undertaken when, during the course of his workup, his condition deteriorated suddenly because the thrombotic process extended from the hepatic veins into the IVC. The everpresent risk of this complication, and the dangers associated with delaying operation were emphasized by this case. It is concluded that side-to-side portacaval shunt, which decompresses the liver by converting the portal vein into an outflow tract, provides effective treatment of the Budd-Chiari syndrome when the occlusive process is confined to the hepatic veins.

Hepatic venous angiography in the evaluation of cirrhosis of the liver

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Porto-caval and porto-pulmonary anastomoses in Laennec's cirrhosis and in heart failure

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