Hemodynamic changes in patients with portal venous obstruction

Portal Vein Thrombosis in Patients Without Cirrhosis: Current Practical Approaches and Treatment Strategies

Portal vein thrombosis in non-cirrhotic individuals, although uncommon, is an increasingly explored condition that affects mainly young people, consequently representing a significant disease burden. Reports primarily including western European populations have recently shed light regarding the pathophysiology, risk factors, natural history, treatment, and prognosis of this entity. Underlying predisposing conditions are documented in ~70% of cases, encompassing local risk factors, inherited and acquired thrombophilia, cancer, and systemic inflammatory conditions. Non-cirrhotic portal vein thrombosis can cause significant portal hypertension in the acute setting, but, more frequently, significant portal hypertension-related complications arise when the condition becomes chronic and portosystemic collaterals develop, increasing the risk for variceal bleeding and ascites. The diagnostic approach to screen for underlying thrombophilia remains a challenge, and recommendations in this regard, although scarce and backed by scarce evidence, have changed notably in the last years, leaning toward a universal screen in patients who develop this condition without a clear provoking factor. Recently, studies have shown that long-term anticoagulation may be appropriate even in the absence of clear provoking factors or underlying thrombophilia. Future studies should address which patients may benefit from this approach, which patients may not need it, and what the most appropriate strategies are to approach patients who do not recover portal vein patency with anticoagulation to further prevent portal hypertension-related complications.

Portal vein thrombosis: diagnosis, management, and endpoints for future clinical studies

Portal vein thrombosis (PVT) refers to the development of a non-malignant obstruction of the portal vein, its branches, its radicles, or a combination. This Review first provides a comprehensive overview of all aspects of PVT, namely the specifics of the portal venous system, the risk factors for PVT, the pathophysiology of portal hypertension in PVT, the interest in non-invasive tests, as well as therapeutic approaches including the effect of treating risk factors for PVT or cause of cirrhosis, anticoagulation, portal vein recanalisation by interventional radiology, and prevention and management of variceal bleeding in patients with PVT. Specific issues are also addressed including portal cholangiopathy, mesenteric ischaemia and intestinal necrosis, quality of life, fertility, contraception and pregnancy, and PVT in children. This Review will then present endpoints for future clinical studies in PVT, both in patients with and without cirrhosis, agreed by a large panel of experts through a Delphi consensus process. These endpoints include classification of portal vein thrombus extension, classification of PVT evolution, timing of assessment of PVT, and global endpoints for studies on PVT including clinical outcomes. These endpoints will help homogenise studies on PVT and thus facilitate reporting, comparison between studies, and validation of future studies and trials on PVT.

The Role of Imaging in Portal Vein Thrombosis: From the Diagnosis to the Interventional Radiological Management

PURPOSE

To illustrate diagnostic and interventional imaging for the characterization and treatment of portal vein thrombosis (PVT).

INTRODUCTION

The broad spectrum of congenital and acquired PVT manifestations is illustrated, with a focus on the pediatric population; diagnostic and interventional imaging techniques are described.

DESCRIPTION

PVT frequently presents as an incidental finding at imaging in the screening for liver diseases or for other unrelated reasons. PVT can be classified based on: extension (intrahepatic, extrahepatic, involving the spleno-mesenteric tract, etc.); degree (partial or complete); onset (acute or chronic); and with or without cavernomatous transformation. This comprehensive review relies on the experience gained from a large series of congenital and acquired PVT in a referral center for pediatric and adult liver transplantation. Diagnostic and interventional imaging techniques are described, including: color-Doppler and contrast-enhanced Ultrasound; CT and MR angiography; retrograde portography; percutaneous transhepatic, transplenic, and transmesenteric portography; transjugular intrahepatic portosystemic shunt creation. Pre- and post-operative imaging assessment of the surgical meso-rex bypass is discussed. The description is enriched with an original series of pictorial imaging findings.

CONCLUSION

PVT is a clinical condition associated with significant morbidity and mortality. Diagnostic and interventional imaging plays a crucial role in both conservative and operative management.

Association of Nonmalignant Portal Vein Thrombosis and Outcomes after Transjugular Intrahepatic Portosystemic Shunt in Patients with Cirrhosis

Purpose To assess the effects of preexisting nonmalignant portal vein thrombosis (PVT) on mortality, clinical relapse, shunt dysfunction, and overt hepatic encephalopathy (HE) after transjugular intrahepatic portosystemic shunt (TIPS) placement. Materials and Methods This retrospective study was approved by the institutional ethics committee, and written informed consent was obtained from all patients. From March 2001 to December 2014, 1171 consecutive patients with cirrhosis (762 men, 409 women; mean age, 50.0 years ± 12.8) and PVT (n = 212; 18%) or without PVT (n = 959; 82%) who underwent TIPS placement were included. The association between PVT and outcomes after TIPS placement was measured by using Fine and Gray competing risk regression model after adjusting for important baseline characteristics or by using propensity score. The Wald test was used to assess the homogeneity of the effects of PVT across different strata (stratified PVT according to the stages, degrees, and extents) and major subgroups. Results During a median follow-up period of 28.4 months, 507 (43%) patients died, 373 (32%) experienced clinical relapse, 217 (19%) developed shunt dysfunction, and 475 (41%) experienced overt HE. Compared with patients without PVT, patients with PVT had a similar risk of mortality (adjusted hazard ratio, 0.82; 95% confidence interval [CI]: 0.63, 1.09; P = .17), clinical relapse (adjusted hazard ratio, 1.24; 95% CI: 0.92, 1.69; P = .15), shunt dysfunction (adjusted hazard ratio, 1.03; 95% CI: 0.70, 1.51; P = .43), and overt HE (adjusted hazard ratio, 0.88; 95% CI: 0.70, 1.11; P = .29). Furthermore, the effects of PVT were consistent across the relevant strata and subgroups. Conclusion There was no evidence that preexisting PVT was associated with an improved or worsened outcome after TIPS. © RSNA, 2017 Online supplemental material is available for this article.

Sport-Related Portal Vein Thrombosis: An Unusual Complication

Portal vein thrombosis (PVT) is an uncommon condition usually associated with hypercoagulable states or liver cirrhosis. PVT due to sports-related injuries is rarely reported and, to the best of our knowledge, only two cases have been reported thus far. Brazilian jiu-jitsu (BJJ) is a form of martial arts and is considered very safe with minimal risk for injury. It has growing popularity worldwide. Here, we report the first case of PVT secondary to abdominal trauma related to the practice of (BJJ) in an otherwise healthy 32-year-old man with no other traditional risk factors for PVT.

Prevalence and pattern of growth abnormalities in children with extrahepatic portal vein obstruction: Response to shunt surgery

OBJECTIVE

Growth retardation is common in children with extrahepatic portal vein obstruction (EHPVO) and growth hormone (GH) resistance may play a dominant role. The aim of this study was to ascertain growth parameters and growth-related hormones in children with EHPVO, comparing with controls and to study the response of shunt surgery on growth parameters.

MATERIALS AND METHODS

The auxological and growth-related hormone profile (GH; insulin-like growth factor binding protein-3 [IGFBP-3] and IGF-1) of thirty children with EHPVO were compared with controls. The effect of shunt surgery on growth parameters in 12 children was also studied.

RESULTS

The mean height standard deviation score (HSDS) of cases (-1.797 ± 1.146) was significantly lower than that of controls (-0.036 ± 0.796); the mean weight SDS of cases (-1.258 ± 0.743) was also lower than that of controls (-0.004 ± 0.533). The mean GH level of cases (5.00 ± 6.46 ng/ml) was significantly higher than that of controls (1.78 ± 2.04 ng/ml). The mean IGF-1 level of cases (100.25 ± 35.93 ng/ml) was significantly lower as compared to controls (233.53 ± 115.06 ng/ml) as was the mean IGFBP-3 level (2976.53 ± 1212.82 ng/ml in cases and 5183.28 ± 1531.28 ng/ml in controls). In 12 patients who underwent shunt surgery, growth parameters significantly improved.

CONCLUSIONS

Marked decrease in weight and height SDSs associated with GH resistance is seen in children with EHPVO, which improves with shunt surgery.

Review article: portal vein obstruction--epidemiology, pathogenesis, natural history, prognosis and treatment

BACKGROUND

Portal vein obstruction may be due to portal vein thrombosis (PVT) or its sequale, the portal cavernoma. PVT is a common complication in liver cirrhosis, however, it may also occur as a primary vascular disorder, in absence of any liver disease.

AIM

To review the current knowledge on nomenclature, etiology, pathophysiology, clinical presentation, diagnostic workup and management of adult patients with obstruction in the portal vein, either as a primary vascular disease in adults, or as a complication of liver cirrhosis.

METHODS

A structured search in PubMed was performed using defined keywords (portal vein obstruction, extra-hepatic portal vein obstruction, PVT and portal cavernoma), including full text articles and abstracts in English language.

RESULTS

Several causes, operating both at local and systemic level, might play an important role in the pathogenesis of PVT. Frequently, more than one risk factor could be identified; however, occasionally no single factor is discernible. Diagnosis of portal vein obstruction depends on clinical presentation, imaging and laboratory investigations. Prompt treatment greatly affects the patient's outcome.

CONCLUSIONS

Portal vein obstruction occurring either due to thrombosis in the portal vein or due to the portal cavernoma, can contribute to significant morbidity and mortality in patients with or without cirrhosis. In recent years our understanding of etio-pathogenesis of portal vein obstruction has evolved tremendously, which has led to significant improvement in treatment outcomes. There are still areas where more studies are needed to better clarify the management issues of portal vein obstruction.

Chronological changes in renal vascular reactivity in portal hypertensive rats

BACKGROUND

Circulatory dysfunction in portal hypertension is characterized by increased cardiac output, decreased systemic vascular resistance, a fall in mean arterial pressure secondary to splanchnic and systemic vasodilation and hence renal hypoperfusion. Previous studies have disclosed that renal vasculatures of portal hypertensive rats had lower perfusion pressure and hyporesponsiveness to endogenous vasoconstrictors. However, the sequences of altered renal haemodynamics have never been described. This study aimed to explore the evolution of renal vascular hyporeactivity and associated mechanisms during portal hypertension.

MATERIALS AND METHODS

All rats were randomized into partial portal vein ligation (PVL) or shamed surgery. Isolated kidney perfusion was performed at postoperative day 1, 4, 7 and 14, respectively, to evaluate chronologically renal vascular response to endothelin-1. Renal arteries and kidneys were harvested for further analysis.

RESULTS

Impaired renal vascular reactivity to endothelin-1 developed 1 week following PVL. There were extensive up-regulations of vasodilative nitric oxide synthase (NOS) and cyclooxygenase-2 in renal arteries of PVL rats. Among them, the changes in endothelial NOS paralleled with the evolution of renal vascular hyporesponsiveness. Preincubation of NOS inhibitor attenuated the renal vascular hyporeactivity in PVL rats. Up-regulated NOS and down-regulated cyclooxygenase-2 in kidneys of PVL rats might play a critical role to maintain renal circulation and body fluid homoeostasis in response to systemic hypotension.

CONCLUSIONS

This investigation highlights the versatile nature of renal vasculatures in portal hypertension, which is replete with compensatory mechanisms. It may help to unveil potential mechanisms of severe renal dysfunction in advanced liver disease.

Portal vein thrombosis: a clinician-oriented and practical review

With advances in modern imaging techniques, portal vein thrombosis (PVT) is being increasingly diagnosed. It has a wide ranging clinical spectrum from being an asymptomatic state to a potentially life-threatening situation. It is not unusual to find it as an incidental finding in the abdominal imagings done for other reasons. It is commonly associated with cirrhosis and abdominal malignancies and also has a strong association with prothrombotic disorders. It is often difficult for the clinicians to decide whether PVT is acute or chronic. This poses great challenges to its management strategies that include anticoagulants, thrombolysis, and surgical options. Timely diagnosis and appropriate management have great bearings on its outcomes of morbidity and mortality. In this clinician-oriented review, we have provided a concise review of clinical aspects of PVT and discussed various management strategies while addressing the common questions that come to a physician's mind dealing with such a patient.

What we should know about portal vein thrombosis in cirrhotic patients: a changing perspective

Portal vein thrombosis (PVT) is one of the most common complications occurring during the natural course of liver cirrhosis. Even though PVT is often asymptomatic, the worsening of liver function, an unexpected episode of gastrointestinal bleeding or ascitic decompensation may be landmarks of PVT development. Beyond these clinical manifestations, it is debated whether PVT really has an impact on liver cirrhosis natural history or rather represents only one of its consequences. Probably PVT development should not only be considered as a matter of impaired blood flow or pro-coagulation tendency. On one hand, PVT seems a consequence of the worsening in portal vein outflow due to the increased hepatic resistance in cirrhotic livers. On the other hand, vascular microthrombosis secondary to necroinflammation may cause liver ischemia and infarction, with loss of hepatic tissue (parenchymal extinction) which is replaced by fibrotic tissue. Therefore, PVT might also be considered as the overt manifestation of the liver fibrosing process evolution and anticoagulant therapy may thus have microscopic indirect effects also on the progression of liver disease. At present, a connection between PVT development and the progression of liver fibrosis/cirrhosis has not yet been demonstrated. Nevertheless, it is not clear if PVT development may worsen cirrhotic patients' outcome by itself. Some authors tried to assess liver transplant benefit in PVT cirrhotic patients but data are contrasting. In this review, we will try to answer these questions, providing a critical analysis of data reported in literature.

Surgical complications following liver transplantation in patients with portal vein thrombosis--a single-center perspective

INTRODUCTION

Portal vein thrombosis (PVT) was once considered a contraindication for liver transplantation (LTx) because of technical difficulties. Though no longer a contraindication, it remains a risk factor.

AIM

A study of surgical complications following LTx in patients with and without PVT.

PATIENTS AND METHODS

A retrospective review of 1,171 consecutive patients who underwent LTx between June 1995 and June 2007 was performed, and 78 recipients with PVT (study group) were compared with a stratified random sample of 78 contemporous recipients without PVT (control group) for postoperative complications. Both groups were comparable with respect to age, sex, race, and other confounding variables.

RESULTS

The rate of primary nonfunction (PNF) in the study and control groups was 9.0% and 1.3%, (p = 0.063), while that of retransplantation was 17.9% and 7.7% (p = 0.055), respectively. The mean donor risk index (DRI) among the patients with and without PNF in the study group was 2.58 +/- 0.44 and 2.08 +/- 0.42, respectively (p = 0.014). A significantly higher number of packed red blood cells and fresh frozen plasma transfusions were observed in study group compared to controls (p = 0.012, 0.007, respectively).

CONCLUSION

A higher rate of PNF was related to the complexity of the surgical procedure and the use of donor livers with a high DRI. Higher rates of PNF eventually led to a higher rate of retransplant. A strategy of offering donor livers with a low DRI might be helpful in decreasing the rate of PNF. Further, a PV interposition graft in difficult cases instead of thrombectomy could lead to a lower rethrombosis rate.

Portal vein thrombosis: insight into physiopathology, diagnosis, and treatment

Portal vein thrombosis (PVT) is a relatively common complication in patients with liver cirrhosis, but might also occur in absence of an overt liver disease. Several causes, either local or systemic, might play an important role in PVT pathogenesis. Frequently, more than one risk factor could be identified; however, occasionally no single factor is discernable. Clinical examination, laboratory investigations, and imaging are helpful to provide a quick diagnosis, as prompt treatment might greatly affect a patient's outcome. In this review, we analyze the physiopathological mechanisms of PVT development, together with the hemodynamic and functional alterations related to this condition. Moreover, we describe the principal factors most frequently involved in PVT development and the recent knowledge concerning diagnostic and therapeutic procedures. Finally, we analyze the implications of PVT in the setting of liver transplantation and its possible influence on patients' future prognoses.

Underlying mechanism of portal hypertensive gastropathy in cirrhosis: a hemodynamic and morphological approach

BACKGROUND AND AIM

Portal hypertensive gastropathy (PHG) is an important cause of bleeding in patients with cirrhosis associated with portal hypertension. Histologically, the condition is characterized by dilation of the mucosal and submucosal vessels of the stomach; however, its mechanisms remain unclear. The aim of the present cross-sectional study was to evaluate the role of portal and systemic hemodynamic features, humoral factors and hepatocellular function in the development and severity of PHG in patients with cirrhosis.

METHODS

Forty-six patients with cirrhosis of different etiologies underwent endoscopy. Portal hypertension was evaluated by hepatic venous pressure gradient (HVPG). The gastric mucosa was analyzed using two diagnostic methods: endoscopy according to the McCormack criteria and histological by histomorphometric analysis.

RESULTS

The prevalence of PHG according to the endoscopic and histomorphometric methods was 93.4% and 76.1%, respectively. There were no statistically significant differences in HVPG measurements between the patients with mild (16.0 +/- 5.9 mmHg) and severe PHG (16.9 +/- 6.5 mmHg; P = 0.80) or between patients who did not have (15.2 +/- 8.0 mmHg) and those who had PHG (16.3 +/- 5.7 mmHg). No correlation was found between the presence or severity of PHG and systemic vascular resistance index (P = 0.53 and 0.34, respectively), Child-Pugh classification (P = 0.73 and 0.78, respectively) or glucagon levels (P = 0.59 and 0.62, respectively).

CONCLUSIONS

The present data show no correlation between the presence or the severity of PHG and portal pressure, Child-Pugh classification or systemic hemodynamics, suggesting that other factors may be involved in the physiopathology of PHG, such as local gastric mucosal factors or other underlying factors.

Systemic and pulmonary hemodynamics in patients with extrahepatic portal vein obstruction is similar to compensated cirrhotic patients

BACKGROUND

Patients with cirrhosis and portal hypertension exhibit a hyperdynamic circulation manifesting as increased cardiac output, heart rate and plasma volume; and decreased arterial blood pressure, systemic vascular resistance, and pulmonary vascular resistance. It is believed that these changes are related to both hepatocellular dysfunction and portal hypertension. However, the role of portal hypertension per se in producing these changes in circulation has not been clear. Extrahepatic portal vein obstruction (EHPVO), a vascular disorder of the liver characterized by cavernomatous transformation of the main portal vein, is an excellent model to study the role of portal hypertension per se in producing these changes because there is no hepatic dysfunction in EHPVO. The main aim of our study was, therefore, to evaluate alterations of systemic and pulmonary vascular systems in patients with EHPVO and compare them with patients with compensated cirrhosis.

PATIENTS AND METHODS

Consecutive patients of EHPVO, 15 years or older, and past variceal bleeders were studied. For comparison, consecutive patients with compensated cirrhosis and history of variceal bleed, matched for variceal status, and body surface area were included. The hemodynamic studies included the measurements of cardiac index (by Fick's oxygen method), and systemic and pulmonary vascular resistance indices.

RESULTS

Fifteen patients of EHPVO and same number of controls (compensated cirrhotics) were included in the study. The baseline parameters in the two groups were comparable. Both EHPVO patients and cirrhotics had similar values in all the measured systemic and pulmonary hemodynamic parameters. The median (range) cardiac index in EHPVO was 3.8 (2.3-7.7) l min(-1) m(-2), whereas it was 4.4 (2.8-8.9) l min(-1) m(-2) in cirrhosis (P = 0.468). The median (range) systemic vascular resistance index in EHPVO was 1,835 (806-3400) dyne s cm(-5) m(-2), which was similar to that in cirrhotic patients (1,800 [668-3022], P = 0.520). Similarly, the values of median (range) pulmonary vascular resistance index were comparable in the two groups (71 [42-332] vs. 79 [18-428], P = 0.885). A subgroup analysis was done for 8 patients of EHPVO and 8 age-matched compensated cirrhotic patients, which also revealed similar values of cardiac index, cardiac output, systemic vascular resistance index, systemic vascular resistance, pulmonary vascular resistance index, and pulmonary vascular resistance in the two groups.

CONCLUSIONS

EHPVO patients have hyperdynamic circulation manifested by high cardiac index and low systemic and pulmonary vascular resistance indices. These hemodynamic changes are comparable with compensated cirrhotic patients who have similar grade of portal hypertension. This suggests a predominant role of portal hypertension per se in the genesis of systemic and pulmonary hemodynamic alterations.

Relation of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 levels to growth retardation in extrahepatic portal vein obstruction

BACKGROUND

Growth retardation has been described in patients with extrahepatic portal vein obstruction (EHPVO). An abnormal growth hormone (GH)-insulin-like growth factor (IGF) axis has been postulated as a possible etiology. We compared anthropometric parameters and IGF-1 and insulin-like growth factor binding protein-3 (IGFBP-3) levels in patients with EHPVO with their siblings as controls.

METHODS AND PATIENTS

Consecutive patients diagnosed with EHPVO who presented to out-patient clinic in Department of Gastroenterology between February 2005 and February 2006 were enrolled along with their siblings whenever possible. After detailed history and clinical examination, anthropometric parameters such as age, height, weight, and mid-parental height were measured in patients and controls. IGF-1 and IGFBP-3 levels were also estimated.

RESULTS

Fifty-two patients (40 males, 32 adults) were enrolled. Sibling controls were available for 28 patients. Variceal bleeding was the presenting symptom in 41 of 52 (78.8%) patients. Target height was not achieved in 7 of 32 (22.6%) adults and 6 of 20 (30%) children, showing evidence of growth retardation. The mean IGF-1 levels in patients and controls were 124.71 +/- 65.49 ng/ml and 233 +/- 76.98 ng/ml (P < 0.01), respectively. The mean IGFBP-3 levels in patients and controls were 2.90 +/- 1.07 mug/ml and 4.22 +/- 0.77 mug/ml (P < 0.01), respectively. Hormonal levels between those with and without evidence of growth retardation did not differ significantly. Duration of symptoms, spleen size, platelet count, and age of presentation did not correlate with anthropometry and hormonal levels.

CONCLUSIONS

Growth retardation by anthropometry was documented in a quarter of patients with EHPVO. All patients had significantly low IGF-1 and IGFBP-3 levels in comparison with controls despite normal anthropometry in majority of patients (75%).

Hemodynamic evaluation before liver transplantation: insights into the portal hypertensive syndrome

The cardiac hemodynamics of patients awaiting liver transplantation is complex. Coronary atherosclerosis, a hyperdynamic circulatory state and cirrhotic cardiomyopathy are present to a variable degree in this population. In this contribution to the Symposium on Portal Hypertension, we expand on our published experience with coronary angiography and cardiac hemodynamics at the time of evaluation of candidacy for liver transplantation in a cohort of 161 patients. Although we confirmed the relation of systemic hemodynamics with the degree of liver failure, we noted a higher prevalence of high output heart failure, defined as an increased left ventricular end-diastolic pressure in the setting of an elevated cardiac output, most notably in patients classified as Child C. Most patients with high pulmonary artery pressure also exhibited evidence of elevated left ventricle filling pressures. A low systemic vascular resistance, a marker of arterial vasodilatation, was similar in the presence of atherosclerosis, a condition where impaired vasorelaxation occurs as a result of endothelial dysfunction. The high prevalence of coronary artery disease in this series supports the observations that atherosclerosis is a major issue in the current population with cirrhosis awaiting liver transplantation. A lower sensitivity of noninvasive screening tools for the detection of coronary atherosclerosis is likely the result of the interaction of the hyperdynamic circulation with the performance of these tests.

Systemic hemodynamics, vasoactive systems, and plasma volume in patients with severe Budd-Chiari syndrome

Budd-Chiari syndrome (BCS) causes postsinusoidal portal hypertension, which leads to complications similar to those observed in cirrhosis. However, no studies have investigated whether patients with BCS develop the hyperdynamic circulatory syndrome present in patients with cirrhosis who have portal hypertension. We evaluated systemic and cardiopulmonary hemodynamics, plasma renin activity, aldosterone and norepinephrine levels, and plasma volume in patients with BCS admitted for complications of portal hypertension. BCS patients had mean systemic and cardiopulmonary pressures and cardiac indices that were within the normal range but were significantly different from those of a group of patients with cirrhosis matched by sex, body surface, and liver function (cardiac index 3.1 +/- 0.7 vs. 4.9 +/- 1.2 L.min(-1).m(-2); P < .001; systemic vascular resistance [SVR] index, 2,189 +/- 736 vs. 1,377 +/- 422 dyne.s.cm(-5).m(-2), P < .001). Despite normal systemic vascular resistance, BCS patients had activation of the neurohumoral vasoactive systems, as evidenced by increased plasma renin activity, aldosterone and norepinephrine levels (15.0 +/- 21.5 ng/mL . h, 76.7 +/- 106.8 ng/dL, 586 +/- 868 pg/mL; respectively) and plasma volume expansion. The analysis of individual BCS patients identified that 7 of the 21 patients actually had reduced SVR index. These patients had the greatest plasma volume expansion. A significant inverse correlation between plasma volume and SVR index was observed. In conclusion, patients with BCS had activation of vasoactive neurohumoral systems and expanded plasma volume. This outcome was observed even though most of these patients did not exhibit systemic vasodilation and cardiac output was not increased, in marked contrast with what is observed in patients with cirrhosis.

Orthotopic Liver Transplantation With Vena Cava Preservation in Cirrhotic Patients: Is Systematic Temporary Portacaval Anastomosis a Justified Procedure?

INTRODUCTION

We evaluated the peri- and postoperative effects of the lack of a temporary portocaval anastomosis (TPCA) during orthotopic liver transplantation (OLT) in 84 patients with cirrhosis.

PATIENTS AND METHODS

From December 1996 to December 2002, 156 liver transplant recipients included (54%; 60 men and 24 women) of mean age 52 +/- 9 years with portal hypertension. In whom peri- and postoperative data were analyzed.

RESULTS

The median fall in mean arterial pressure upon vascular clamping and unclampings was 20 mm Hg (range 15 to 75), while the median duration of portal vein clamping was 77 minutes. The median amount of blood autotransfusion was 1100 mL (range 0 to 5400). The median number of red blood cell and fresh-frozen plasma units transfused were 5 and 6.5, respectively. The median intraoperative urinary output was 72 mL/h (range 11 to 221). Three patients (3.5%) presented a perioperative complication, but no perioperative death was observed. Six patients experienced an early postoperative complication (<10 days): five hemodynamic complications and one transient renal failure, which did not require hemodialysis. One patient (1%) died at 12 hours after OLT from acute pulmonary edema.

CONCLUSION

This study shows that systematic TPCA during OLT with preservation of the native retrohepatic vena cava in cirrhotic patients does not appear to be justified. In contrast, peri- and postoperative hemodynamic parameters as well as blood component requirements were comparable to those of the literature reporting OLT with straightforward TPCA.

The role of nitric oxide synthase isoforms in extrahepatic portal hypertension: studies in gene-knockout mice

BACKGROUND & AIMS

Considerable debate exists concerning which isoform of nitric oxide synthase (NOS) is responsible for the increased production of NO in PHT. We used the portal vein ligation model of PHT in wild-type and eNOS- or iNOS-knockout mice to definitively determine the contribution of these isoforms in the development of PHT.

METHODS

The portal vein of wild-type mice, or those with targeted mutations in the nos2 gene (iNOS) or the nos3 gene (eNOS), was ligated and portal venous pressure (Ppv), abdominal aortic blood flow (Qao), and portosystemic shunt determined 2 weeks later.

RESULTS

In wild-type mice, as compared with sham-operated controls, portal vein ligation (PVL) resulted in a time-dependent increase in Ppv (7.72 +/- 0.37 vs 17.57 +/- 0.51 cmH(2)O, at 14 days) concomitant with a significant increase in Qao (0.12 +/- 0.003 vs 0.227 +/- 0.005 mL/min/g) and portosystemic shunt (0.47% +/- 0.01% vs 84.13% +/- 0.09% shunt). Likewise, PVL in iNOS-deficient mice resulted in similar increases in Ppv, Qao, and shunt development. In contrast, after PVL in eNOS-deficient animals, there was no significant change in Ppv (7.52 +/- 0.22 vs 8.07 +/- 0.4 cmH(2)0) or Qao (0.111 +/- 0.01 vs 0.14 +/-.023 mL/min/g). However, eNOS (-/-) mice did develop a substantial portosystemic shunt (0.33% +/- 0.005% vs 84.53% +/- 0.19% shunt), comparable to that seen in wild-type animals after PVL.

CONCLUSIONS

These data support a key role for eNOS, rather than iNOS, in the pathogenesis of PHT.

[Portal cavenorma: diagnosis, aetiologies and consequences]

Portal cavernoma is a network of veins whose caliber, initially millimetric or microscopic, is increased and which contain hepatopedal portal blood. It results from occlusion, thrombotic and always chronic, of the extra-hepatic portal system. Diagnosis is mainly done by imaging. Clinical signs of portal cavernoma are usually related to extra-hepatic portal hypertension (hematemesis due to rupture of oeso-gastric varices, splenomegaly, rectal bleeding from ano-rectal varices, growth retardation in children) and sometimes to the cause of portal hypertension (abdominal pain, venous bowel infarction). Occurrence of portal thrombosis is often the conjunction of a local cause and a prothrombotic disorder which must be systematically detected. Biliary consequences of cavernoma are related to compression of common bile duct and are usually asymptomatic. In case of jaundice or cholangitis, portal decompression by portosystemic shunt can be performed to treat both biliary symptoms and portal hypertension.

Hepatic venous pressure gradients measured by duplex ultrasound

AIMS

The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index.

METHOD

We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made.

RESULTS

Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r=0.83, P<0.0001) and with the Child-Pugh score (r=0.63, P<0.0001). An acceleration index cut-off value of 1m.s(-2) provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient>12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r=0.45,P=0.01) and portal vein velocity (r=0.40,P=0.044), was also noted.

CONCLUSION

Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension.

Role of shear stress in aortic eNOS up-regulation in rats with biliary cirrhosis

BACKGROUND & AIMS

In rats with portal vein stenosis, the initial cause of aortic nitric oxide (NO) overproduction might be overactivation of endothelial NO synthase (eNOS) related to increased shear stress. Cardiac output is higher in cirrhosis than in extrahepatic portal hypertension. The aims of this study were to evaluate the role of shear stress, vascular endothelial growth factor (VEGF), and cytokines in aortic eNOS up-regulation in rats with biliary cirrhosis and to compare these results with those in rats with portal vein stenosis.

METHODS

NOS activities, NOS protein, heat shock protein (Hsp) 90, and VEGF expressions were studied in rat aortas. Propranolol was administered to rats with cirrhosis to reduce cardiac output and thus shear stress.

RESULTS

In cirrhotic rats, the aortic eNOS protein was 3.0 and 1.7 times higher than in control and portal vein-stenosed rats, respectively. In cirrhotic rats, the Hsp90 content was 3.2 and 2.2 times higher than in control and portal vein-stenosed rats, respectively. Propranolol decreased NOS activity by 47% and eNOS and Hsp90 expression by 75% and 72%, respectively. Aortic VEGF expression was decreased in cirrhotic rats. VEGF-induced stimulation of NOS activity was greater in aortas from control rats than in aortas from portal vein-stenosed or cirrhotic rat aortas. eNOS expression was up-regulated after VEGF incubation. After lipopolysaccharide administration, eNOS expression did not change in portal vein-stenosed or cirrhotic rats.

CONCLUSIONS

This study shows that in aortas from rats with biliary cirrhosis, systemic vasodilation depends mainly on eNOS up-regulation related to shear stress.

Portal vein thrombosis: a concise review

Portal vein thrombosis (PVT) is an uncommon cause for presinusoidal portal hypertension. Although several predisposing conditions are known to exist in the background of PVT, there still remains a proportion of patients in whom the etiology is not known and the pathogenesis is unclear. In this review we summarize the literature on PVT and present the current knowledge about the precipitating factors of PVT. Further, we discuss the advances in the radiological diagnosis that have improved diagnostic accuracy and are noninvasive. Finally, we discuss the treatment options for patients who have varying extents of thrombosis in the portal vein and specifically focus on PVT that is encountered before and after liver transplantation.

Prevalence of autonomic dysfunction in cirrhotic and noncirrhotic portal hypertension

OBJECTIVE

Autonomic dysfunction is common in patients with cirrhosis of the liver, but more so in patients with decompensated state, and is associated with increased mortality. We evaluated the presence and extent of autonomic dysfunction in patients with extrahepatic portal venous obstruction (EHPVO) and noncirrhotic portal fibrosis (NCPF), diseases with relatively preserved liver functions.

METHODS

Heart rate variability in response to standing, deep breathing, and Valsalva maneuver and blood pressure response to sustained handgrip and standing were studied in 18 patients with EHPVO (13 mol/L, 5 F, mean age 15.2 +/- 6 yr), 12 patients with NCPF (5 mol/L, 7 F, mean age 26.4 +/- 8 yr), 15 patients with cirrhosis (7 mol/L, 8 F, mean age 12.6 +/- 6 yr), and 17 healthy controls (11 mol/L, 6 F, mean age 18.6 +/- 3 yr). Time-domain parameters of heart rate variability on 24-h ambulatory monitoring were assessed in all the patients.

RESULTS

Autonomic dysfunction was observed in 67% of EHPVO, 25% of NCPF, and 80% of cirrhotic subjects but none of the healthy controls (p < 0.05). Four of five time-domain heart rate variability indices showed significant abnormalities in patients with EHPVO (p < 0.05) and cirrhosis (p < 0.05), when compared with patients with NCPF and healthy controls.

CONCLUSIONS

Autonomic dysfunction is frequently encountered in patients with EHPVO and cirrhosis, and the presence of autonomic dysfunction in patients with noncirrhotic portal hypertension suggests a primary role of portal hypertension per se in the dysfunction.

Pathogenesis of portal hypertension

Portal hypertension is defined by an elevation in portal pressure and is associated with haemodynamic alterations. Haemodynamic changes are characterized by a hyperdynamic circulation in the splanchnic and systemic territories and a reduced pressure effect of vasoconstrictive substances. They were observed in both patients and animals with different types of portal hypertension. In this review, the main results and their mechanisms of the splanchnic and systemic haemodynamic alterations in portal hypertension are discussed.

The hyperdynamic circulation in cirrhosis: an overview

The hyperdynamic circulation begins in the portal venous bed as a consequence of portal hypertension due to the increased resistance to flow from altered hepatic vascular morphology of chronic liver disease. Dilatation of the portal vein is associated with increased blood flow, as well as the opening up or formation of veno-venous shunts and splenomegaly. At the same time, portal hypertension leads to subclinical sodium retention resulting in expansion of all body fluid compartments, including the systemic and central blood volumes. This blood volume expansion is associated with vasorelaxation, as manifested by suppression of the renin--angiotensin--aldosterone system, initially only when the patient is in the supine position. Acute volume depletion in such patients results in normalisation of the hyperdynamic circulation, whilst acute volume expansion results in exaggerated natriuresis. As liver disease progresses and liver function deteriorates, the systemic hyperdynamic circulation becomes more manifest with activation of the renin--angiotensin--aldosterone system. The presence of vasodilatation in the presence of highly elevated levels of circulating vasoconstrictors may be explained by vascular hyporesponsiveness due to increased levels of vasodilators such as nitric oxide, as well as the development of an autonomic neuropathy. However, vasodilatation is not generalised, but confined to certain vascular beds, such as the splanchnic and pulmonary beds. Even here, the status may change with the natural history of the disease, since even portal blood flow may decrease and become reversed with advanced disease. The failure of these changes to reverse following liver transplantation may be due to remodelling and angiogenesis.

Cardiac excitation-contraction coupling in the portal hypertensive rat

Basal contractility and responses to beta-adrenoceptor activation are compromised in hearts from rats with chronic portal vein stenosis. Here we report the effect of partial ligation of the portal vein on myocardial G protein expression, beta-adrenoceptor-G protein coupling, and excitation-contraction coupling (ECC). Contractility (dT/dt) was reduced 30-50% in right and left ventricles, but the rate of relaxation (-dT/dt) was unaffected. Isoproterenol-induced positive inotropism was diminished, but there was no difference in ED(50). The concentration-dependent increase in -dT/dt was unaffected. G(s)alpha and G(i)alpha expression, cholera toxin- and pertussis toxin-induced ADP-ribosylation, and formation of the agonist-receptor-G(s) complex were unaffected by portal vein stenosis. Of the components of ECC examined, the caffeine-sensitive sarcoplasmic reticulum Ca(2+) pool was reduced 35%, although the Ca(2+) uptake and release processes were unchanged; the apparent density of L-type Ca(2+) channels decreased 60% with no change in affinity; the dihydropyridine Ca(2+) channel agonist BAY K 8644 produced relative changes in dT/dt that were similar in both groups, suggesting normal function in the remaining Ca(2+) channels; and Na(+)/Ca(2+) exchange was reduced 50% in the portal vein stenosis group. These data suggest that the effect of portal vein stenosis on the myocardium is the result of alterations to ECC.

Extrahepatic portal vein obstruction in children: anthropometry, growth hormone, and insulin-like growth factor I

BACKGROUND

Extrahepatic portal vein obstruction has been shown to cause growth retardation in children, though literature is scant. No information is available regarding the cause of growth retardation in these patients.

METHODS

To document the presence of growth retardation in this disease, we studied growth and nutrition in 33 consecutive prepubertal patients. Anthropometry, fasting growth hormone, and insulin-like growth factor I levels were compared in 22 well-nourished patients from this group with 35 age-matched well-nourished controls.

RESULTS

Mean +/- SD height standard deviation score of well-nourished patients (-1.88 +/- 1.33) was significantly below that of the controls (-1.06 +/- 0.64, p < 0.01). Patients also had significantly lower midarm muscle circumference z scores (-2.65 +/- 1.09) than controls (-1.17 +/- 1.09, p < 0.0001), though triceps skinfold thickness z scores were comparable in the two groups (-1.06 +/- 0.68 vs -1.24 +/- 0.79, p = NS). Insulin-like growth factor I z scores were significantly lower in patients (-1.48 +/- 0.88) than in controls (-0.49 +/- 1.09, p < 0.001), whereas basal growth hormone was significantly higher in patients (4.60 +/- 3.70 mIU/L) compared with controls (2.66 +/- 0.82, p < 0.01).

CONCLUSION

Extrahepatic portal vein obstruction in children leads to growth retardation. Anthropometric and preliminary hormonal evaluation suggest resistance to the action of growth hormone as a possible mechanism.

Autonomic neuropathy in extra-hepatic portal vein thrombosis: evidence for impaired autonomic reflex arc

BACKGROUND/AIMS

Autonomic dysfunction is common in cirrhosis, and may be associated with increased mortality and hyperdynamic circulatory changes. Our aim was to investigate whether autonomic disturbances occur in extrahepatic portal vein thrombosis and their correlation with hemodynamic abnormalities.

PATIENTS AND METHODS

Heart rate variation in response to standing, deep breathing, and Valsalva maneuver, and blood pressure response to sustained handgrip and to standing, were studied in 16 subjects with portal vein thrombosis (10 males, 30.8+/-2.8 years: mean+/-SE), 12 with cirrhosis (7 males, 52+/-2.3 years), and 10 healthy controls (7 males, 30.8+/-3.0 years). Supine resting, and 10- and 30-min standing epinephrine and norepinephrine levels were measured and results correlated with cardiac output.

RESULTS

Autonomic dysfunction occurred in 62% of portal vein thrombosis and 75% of cirrhosis subjects, but in no controls (p<0.02). Similarly, postural hypotension occurred in portal vein thrombosis (-10.25+/-0.65 mmHg, p=0.003) and cirrhosis (-7.42+/-0.82 mmHg, p=0.007) but not in controls. All groups had similar baseline epinephrine and norepinephrine concentrations. Epinephrine increased significantly in controls (45%, p<0.01 and 49%, p<0.02) after 10 of 30 min standing but not in the portal vein thrombosis or the cirrhotic group, and norepinephrine increased after 10 and 30 min standing in cirrhotics (128%, p<0.004 and 130%, p<0.008) and controls (129%, p<0.002 and 116%, p<0.004), but not portal vein thrombosis (34.5% and 39%, NS vs baseline). Portal vein thrombosis and cirrhosis groups had increased cardiac output (4441+/-509 and 3262+/-292) vs controls (1763+/-212 ml/min/m2, p<0.002), but there was no correlation with autonomic neuropathy or with catecholamine levels.

CONCLUSIONS

Autonomic dysfunction and impaired catecholamine response to orthostatic stress occur commonly in portal vein thrombosis and suggest an impairment of the autonomic reflex arc, but changes do not correlate with hemodynamic abnormalities.

Systemic and splanchnic hemodynamic changes in patients with hepatic schistosomiasis

Although hepatic schistosomiasis is a common cause of portal hypertension, only a few hemodynamic studies, in humans, have been published on this subject. The aim of this study was to determine the systemic and splanchnic hemodynamic changes in hepatic schistosomiasis and to evaluate the influence of liver fibrosis on these changes. A retrospective analysis of a series of 13 patients with hepatic schistosomiasis who had undergone hemodynamic studies was performed. Portal or perisinusoidal fibrosis was present at liver biopsy in 8 patients. The control group included 22 patients with chronic hepatitis and normal hepatic venous pressure gradients. Patients with schistosomiasis exhibited high cardiac index (4.11 +/- 1.15 l.min-1.m-2 vs 2.99 +/- 0.85 l.min-1.m-2; p < 0.05) and low systemic vascular resistance (1039 +/- 316 dyn.s.cm-5 vs 1334 +/- 336 dyn.s.cm-5; p < 0.05). The hepatic venous pressure gradient and hepatic blood flow were normal. Azygos blood flow was markedly increased (0.90 +/- 0.66 l.min-1 vs 0.13 +/- 0.04 l.min-1; p < 0.05). Hemodynamic values were not significantly different between patients with liver fibrosis and those without fibrosis at liver biopsy. In conclusion, patients with hepatic schistosomiasis had a hyperkinetic systemic and splanchnic circulation. In patients with esophageal varices, a normal hepatic venous pressure gradient confirmed presinusoidal portal hypertension. The presence of portal or perisinuoidal fibrosis did not influence hyperdynamic splanchnic state.

Haemodynamic assessment

The degree of portal hypertension and its haemodynamic complications can be easily determined. However, the interpretation of these values is not entirely clear and further clinical and experimental studies are needed to explain why some patients with portal hypertension bleed from oesophageal varices while others do not.

The role of glucagon in the gastric hyperdynamic circulation of cirrhotic portal hypertensive rats

The role of glucagon as a mediator of gastric hyperdynamic circulation, induced by carbon tetrachloride (CCl4), was assessed in cirrhotic rats. A selective elimination of pancreatic glucagon from the circulation was achieved by the intravenous infusion of a glucagon antiserum. Gastric blood flow was measured by laser-Doppler flowmetry. The glucagon antiserum had no effect on the blood flow in the stomach in control rats, while in cirrhotic portal hypertensive rats, the glucagon antiserum significantly reduced gastric blood flow (30%). The glucagon antiserum did not completely exclude the gastric hyperdynamic state in the cirrhotic rats. It would thus appear that glucagon contributes to a portion of the gastric hyperdynamic circulation associated with cirrhotic portal hypertension.

The role of increased nitric oxide in the vascular hyporeactivity to noradrenaline in long-term portal vein ligated rats

To test the possible role of nitric oxide production in long-term portal vein ligation in the rat, where the hyperdynamic circulation was reported to be absent, in vivo experiments on isolated thoracic aortic rings from partial portal vein ligated or sham-operated rats were performed, 6 months postoperatively. The concentration-response curves to noradrenaline of both intact and endothelium-denuded rings from portal hypertensive rats were significantly shifted to the right as compared to those from sham-operated animals. In intact rings, addition of NG-nitro-L-arginine, a specific inhibitor of nitric oxide synthase, resulted in a significant shift of the curves to the left in sham-operated and portal vein ligated rats. In endothelium-denuded rings, addition of NG-nitro-L-arginine resulted in a significant shift of the curves to the left in portal vein ligated but not in sham-operated animals. After blockade of the nitric oxide biosynthesis with NG-nitro-L-arginine, the negative logarithm of the concentration of nonadrenaline causing half-maximal response did not significantly differ any more between portal vein ligated and sham-operated rats; in endothelium-denuded rings hyporeactivity to noradrenaline persisted in portal vein ligated rats. Only in the intact rings did NG-nitro-L-arginine significantly increase the maximal contractions. No differences were demonstrated in endothelium-dependent relaxations to acetylcholine between sham-operated and portal hypertensive animals. From these results, it can be concluded that in vitro aortic hyporeactivity to noradrenaline is still present in long-term portal vein ligated rats, and that it results at least partially from activation of the L-arginine: nitric oxide pathway in the aortic vascular wall.

Role of nitric oxide in hyporeactivity to noradrenaline of isolated aortic rings in portal hypertensive rats

To test the hypothesis that induction of nitric oxide synthase causes systemic vascular hyporesponsiveness to vasopressors in portal hypertension, we performed in vitro experiments on isolated thoracic aortic rings from partial portal vein ligated or sham operated rats at 3 weeks postoperatively. The concentration-response curves to noradrenaline of intact and endothelium-denuded aortic rings from portal hypertensive rats were significantly shifted to the right as compared to those from sham operated animals. Maximal contractions did not significantly differ. Addition of NG-nitro-L-arginine, a specific inhibitor of nitric oxide synthase, shifted the curves to the left in both sham operated and portal hypertensive rats, so that in intact rings, the concentrations of noradrenaline producing half-maximal response did not significantly differ any more between sham operated and portal vein ligated rats. In endothelium-denuded rings, a hyporeactivity to noradrenaline persisted in portal vein ligated rats. Furthermore, NG-nitro-L-arginine induced an additional significant increase in the maximal response to noradrenaline in sham operated as compared to portal hypertensive rats. The endothelium-dependent relaxations to acetylcholine were attenuated in portal hypertensive rats as compared to sham operated animals. From these results, it can be concluded that increased nitric oxide production in the vascular wall of thoracic aorta of portal hypertensive rats is involved in their hyporesponsiveness to noradrenaline. Our findings in endothelium-denuded rings indicate the involvement of the inducible nitric oxide synthase in the smooth muscle layer. Involvement of an inducible nitric oxide synthase in the endothelium cannot be excluded. The endothelial constitutive nitric oxide synthase, however, seems to be suppressed in portal vein ligated rats.

Endotoxin-induced nitric oxide synthesis in the perfused rat liver: effects of L-arginine and ammonium chloride

We used the single-pass-perfused rat liver model to study short-term regulation of endotoxin-inducible nitric oxide synthesis by following the release of nitrite and nitrate, the oxidation products of nitric oxide, into the effluent perfusate. In endotoxin-pretreated livers, the basal nitrite+nitrate release was 5.3 +/- 1.2 nmol.gm liver-1.min-1. Nitrite and nitrate release was stimulated by L-arginine in a dose-dependent and saturable fashion. Maximal nitrite+nitrate release with 1 mmol/L L-arginine infused to the influent perfusate was 10.2 +/- 1.1 nmol.gm liver-1.min-1, with a half-maximal effect at 53 mumol/L L-arginine. In the absence of molecular oxygen, nitric oxide synthesis was inhibited. Ammonium chloride infusion also stimulated nitrite and nitrate release to a maximal rate of 9.2 +/- 0.8 nmol.gm liver-1.min-1 with half-maximal effects at 60 mumol/L ammonium chloride. Ammonium chloride-stimulated nitrite and nitrate release was abolished when urea synthesis was inhibited by bicarbonate-free liver perfusion. Citrulline and ornithine (200 mumol/L each) were without effect on nitrite and nitrate release. L-Nitroarginine methyl ester inhibited both, L-arginine-and ammonium chloride-induced nitrite and nitrate release. Stimulation of nitric oxide synthesis by L-arginine and ammonium chloride addition (1 mmol/L each) was accompanied by a threefold-to-fourfold increase of cyclic GMP release into the effluent perfusate. In livers of endotoxin-pretreated rats the urea production from L-arginine was higher than that in untreated livers, suggesting induction of an L-arginine transport system in hepatocytes by endotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Portal-vein obstruction in children leads to growth retardation

The portal vein is the main source of blood and hepatotrophic factors to the liver. Partial portal-vein ligation in rats results in reduced growth compared with that in control rats. To investigate whether extrahepatic portal vein obstruction occurring in early childhood influences growth in humans, anthropometric and nutritional assessments were prospectively carried out in 61 patients with extrahepatic portal vein obstruction. Comparisons were made with 183 matched healthy controls using National Center of Health Statistics reference. Fifty-one percent of children with extrahepatic portal vein obstruction had stunted growth (height for age less than 90% of normal), compared with 16% of controls (p less than 0.01). Growth retardation was severe in patients with longer (greater than 5 yr) than with shorter (less than 2.5 yr) duration of clinical portal hypertension (height for age, 88.0 +/- 3.2 vs. 95.1 +/- 3.0; p less than 0.01). Little difference was seen in the energy intake (1,302 +/- 463 kcal/day vs. 1,335 +/- 449 kcal/day; p = not significant) and weight for height index (83.6 +/- 9.3 vs. 88.0 +/- 7.9; p = not significant) between extrahepatic portal vein obstruction patients and controls. This suggested that despite comparable nutrition, marked growth retardation occurred in extrahepatic portal vein obstruction patients. Incremental growth velocity was studied in 31 patients; in 24 (73%) the baseline Z score (-2.1 +/- 0.2) had decreased further (-2.4 +/- 0.2) at the end of follow-up (15.5 +/- 1.6 mo). Although the incremental height velocity was only 56% of the expected height, incremental weight gain was 98% of the expected weight for the attained height.(ABSTRACT TRUNCATED AT 250 WORDS)

Persistence of a hyperdynamic circulation in cirrhotic rats following removal of the sympathetic nervous system

The sympathetic nervous system is thought to play a role in the pathogenesis of the hyperdynamic circulation associated with portal hypertension. However, the extent of this role is unknown. After elimination of all neurological control by pithing, systemic and regional hemodynamics were studied in rats with portal hypertension caused by either portal vein stenosis or biliary cirrhosis. In normal rats, pithing induced a two-thirds decrease in mean arterial pressure and cardiac index. Compared with pithed normal rats, pithed portal vein-stenosed rats showed similar values for mean arterial pressure, cardiac index, and portal tributary blood flow. In contrast, pithed cirrhotic rats still showed hyperdynamic circulation with increased cardiac index and portal tributary blood flow. Although pithing dramatically reduced portal pressure in all groups, portal pressure remained significantly higher in portal hypertensive rats than in normal rats. These results indicate that in rats with portal vein stenosis, the sympathetic nervous system plays a major role in hemodynamic alterations, whereas in rats with cirrhosis, nonneurogenic factors participate in the pathogenesis of the hyperdynamic circulation.

High cardiac output of advanced liver disease persists after orthotopic liver transplantation

This study measured cardiac output before and 1 or 2 yr after orthotopic liver transplantation in 23 patients. Cardiac output was measured by thermodilution before transplantation and by first-pass radionuclide angiocardiography at follow-up. Study patients were selected as those doing well clinically and by standard laboratory tests at 1-yr and 2-yr reevaluations with no evidence of rejection: six had mild recurrent hepatitis shown on biopsy samples. Hepatocyte function was normal at the time of the study as shown by galactose elimination capacity of 442 +/- 90 mg/min. Medications were cyclosporine and prednisone in all patients, azathioprine in 10 patients and a combination of antihypertensive therapy to maintain diastolic blood pressure less than 90 mm Hg in 20 patients. Mean (+/- S.D.) pretransplantation cardiac output was 9.1 +/- 3.1 L/min and remained elevated at 8.3 +/- 2.1 L/min 1 yr, and 9.6 +/- 2.6 L/min (n = 13) 2 yr after transplantation. A significant (p less than 0.001) correlation was found between pretransplant and follow-up cardiac output. End diastolic, end systolic and stroke volumes are all increased in a pattern similar to that seen in end-stage cirrhosis. These data show that the high cardiac output of the hyperdynamic state of advanced liver disease persists after liver transplantation. The mechanisms and consequences of this require further study.

Effects of inhibiting nitric oxide biosynthesis on the systemic and splanchnic circulation of rats with portal hypertension

1. The effects of inhibiting endogenous nitric oxide (NO) synthesis with NG-monomethyl-L-arginine (L-NMMA) on the systemic and splanchnic circulation have been investigated in rats with experimental chronic portal hypertension, anaesthetized with ketamine. 2. Portal hypertension was induced by partial portal vein ligation, 2 weeks prior to study. This procedure induced a reduction in systemic arterial blood pressure (MAP), an increase in cardiac output as measured by radiolabelled microspheres, a reduction in peripheral and splanchnic vascular resistance and an increased portal venous inflow (PVI) and portal pressure, as compared to control non-ligated rats. 3. L-NMAA (6.25 and 50 mg kg-1, i.v.) dose-dependently increased MAP, reduced cardiac output and PVI, and increased peripheral and splanchnic vascular resistance. With L-NMMA (50 mg kg-1), PVI and the vascular resistances returned to values comparable to those determined in control non-ligated anaesthetized rats under resting conditions. 4. Porto-collateral resistance was also increased by these doses of L-NMMA, whereas portal pressure was unchanged. The increase in renal blood flow and decrease in renal vascular resistance also seen in portal-hypertensive rats was reversed by L-NMMA (50 mg kg-1). 5. These effects of L-NMMA (50 mg kg-1) were inhibited by prior administration of L-arginine (300 mg kg-1, i.v.). 6. These findings indicate that the chronic hyperdynamic circulatory characteristics following portal vein stenosis can be attenuated by L-NMMA. Thus, the excessive formation of endogenous NO may be implicated in the pathogenesis of the haemodynamic disturbances and splanchnic vasodilatation associated with chronic portal hypertension.

Caliber of splenic and hepatic arteries and spleen size in cirrhosis of different etiology

The caliber of the splenic and hepatic arteries, the hepatic to splenic artery ratio and the spleen size (area of widest spleen section) were evaluated by real time ultrasonography (US) in 88 patients affected by liver cirrhosis of different etiology (26 alcoholic cirrhosis, 43 hepatitis B virus (HBV) related cirrhosis, 8 cryptogenic cirrhosis and 11 primary biliary cirrhosis) and in a control group of 21 normal subjects, in order to assess the possible influence of the etiology of the disease on these morphological parameters. The mean caliber of the hepatic artery was larger, and the mean caliber of the splenic artery smaller in alcoholic than in HBV-related, cryptogenic and in primary biliary cirrhosis. This difference is emphasized when considering the hepatic to splenic artery ratio: this parameter was never greater than 0.9 in all cases of primary biliary cirrhosis, in 38 out of 43 patients with HBV-related cirrhosis and in 6 out of 8 cryptogenic cirrhosis, while in the alcoholic group only in one out of 26 was it less than 0.9. The sensitivity, specificity and accuracy of this ratio in differentiating alcoholic from non-alcoholic cirrhosis was 96%, 88% and 91%, respectively. Splenomegaly resulted more in primary biliary cirrhosis, in HBV-related cirrhosis and in cryptogenic cirrhosis than in the alcoholic form. Finally, a significant correlation was found in all groups of cirrhotic patients between the diameter of the splenic artery and the spleen size. These results show that some ultrasonographic morphological features of liver cirrhosis differ according to its varied etiology, probably reflecting different pathophysiological mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)