Pathophysiology of portal hypertension

A Novel Predictor of Posttransplant Portal Hypertension in Adult-To-Adult Living Donor Liver Transplantation: Increased Estimated Spleen/Graft Volume Ratio

BACKGROUND

In adult living donor liver transplantation (ALDLT), graft-to-recipient weight ratio of less than 0.8 is incomplete for predicting portal hypertension (>20 mm Hg) after reperfusion. We aimed to identify preoperative factors contributing to portal venous pressure (PVP) after reperfusion and to predict portal hypertension, focusing on spleen volume-to-graft volume ratio (SVGVR).

METHODS

In 73 recipients with ALDLT between 2002 and 2013, first we analyzed survival according to PVP of 20 mm Hg as the threshold, evaluating the efficacy of splenectomy. Second, we evaluated various preoperative factors contributing to portal hypertension after reperfusion.

RESULTS

All of the recipients with PVP greater than 20 mm Hg (n = 19) underwent PVP modulation by splenectomy, and their overall survival was favorable compared with 54 recipients who did not need splenectomy (PVP ≤ 20 mm Hg). Graft-to-recipient weight ratio had no correlation with PVP.Multivariate analysis revealed that estimated graft and spleen volume were significant factors contributing to PVP after reperfusion (P < 0.0001 and P < 0.0001, respectively). Furthermore, estimated SVGVR showed a significant negative correlation to PVP after reperfusion (R = 0.652), and the best cutoff value for portal hypertension was 0.95.

CONCLUSIONS

In ALDLT, preoperative assessment of SVGVR is a good predictor of portal hypertension after reperfusion can be used to indicate the need for splenectomy before reperfusion.

The spleen in liver cirrhosis: revisiting an old enemy with novel targets

The spleen is a secondary lymphoid organ which can influence the progression of multiple diseases, notably liver cirrhosis. In chronic liver diseases, splenomegaly and hypersplenism can manifest following the development of portal hypertension. These splenic abnormalities correlate with and have been postulated to facilitate the progression of liver fibrosis to cirrhosis, although precise mechanisms remain poorly understood. In this review, we summarize the literature to highlight the mechanistic contributions of splenomegaly and hypersplenism to the development of liver cirrhosis, focusing on three key aspects: hepatic fibrogenesis, hepatic immune microenvironment dysregulation and liver regeneration. We conclude with a discussion of the possible therapeutic strategies for modulating splenic abnormalities, including the novel potential usage of nanomedicine in non-surgically targetting splenic disorders for the treatment of liver cirrhosis.

Hemodynamic effects of renin-angiotensin-aldosterone inhibitor and β-blocker combination therapy vs. β-blocker monotherapy for portal hypertension in cirrhosis: A meta-analysis

β-blockers are commonly used for the treatment of acute variceal bleeding in cirrhosis. Renin-angiotensin-aldosterone antagonists (angiotensin I-converting enzyme inhibitors, angiotensin receptor blockers and aldosterone antagonists) are potential therapies for portal hypertension. Several studies have compared the renin-angiotensin-aldosterone system (RAAS) inhibitor and β-blocker combination therapy vs. β-blocker monotherapy, with inconsistent results. The aim of the present study was to assess the efficacy of the RAAS inhibitor and β-blocker combination therapy vs. β-blocker monotherapy for hepatic vein pressure gradient (HVPG) reduction in cirrhosis. Studies were obtained using PubMed, Embase, Medline and Cochrane library databases up to July 2015, and the weighted mean difference (WMD) in HVPG reduction was used as a measure of treatment efficacy. In total, three studies (91 patients) were included. When compared to the β-blocker monotherapy, the RAAS inhibitor and β-blocker combination therapy resulted in a significant HVPG reduction [WMD 1.70; 95% confidence interval (CI): 0.52-2.88]. However, there was no significant difference in the heart rate reduction between the monotherapy and combination therapy groups (WMD -0.11; 95% CI: -3.51-3.29). In addition, no significant difference in the hemodynamic response was observed between the two groups (WMD 1.46; 95% CI: 0.93-2.30). In conclusion, the RAAS inhibitor and β-blocker combination therapy reduces portal hypertension significantly and to a greater extent than β-blocker monotherapy. Both therapies reduced the heart rate to similar levels; however, the RAAS inhibitor and β-blocker combination therapy reduced the mean arterial pressure to a greater extent. Due to the limited number of studies included, the data available do not allow a satisfactory comparison of adverse events. Moreover, further larger-scale trials are required in order to strengthen the results of the present study.

Beta adrenergic blockade and decompensated cirrhosis

Non-selective betablockers (NSBBs) remain the cornerstone of medical treatment of portal hypertension. The evidence for their efficacy to prevent variceal bleeding is derived from prospective trials, which largely excluded patients with refractory ascites and renal failure. In parallel to the increasing knowledge on portal hypertension-induced changes in systemic hemodynamics, cardiac function, and renal perfusion, emerging studies have raised concerns about harmful effects of NSBBs. Clinicians are facing an ongoing controversy on the use of NSBBs in patients with advanced cirrhosis. On the one hand, NSBBs are effective in preventing variceal bleeding and might also have beneficial non-hemodynamic effects, however, they also potentially induce hypotension and limit the cardiac reserve. An individualized NSBB regimen tailored to the specific pathophysiological stage of cirrhosis might optimize patient management at this point. This article aims to give practical recommendations on the use of NSBBs in patients with decompensated cirrhosis.

Intrahepatic angiogenesis increases portal hypertension in hepatitis B patients with cirrhosis

AIM

It remains unclear whether intrahepatic angiogenesis increases portal hypertension (PH) in hepatitis B with cirrhosis. We aim to investigate the relationship between intrahepatic angiogenesis and PH in hepatitis B patients with cirrhosis.

METHODS

Sixty hepatitis B patients with cirrhosis and 40 healthy subjects were included in this study. Angiogenesis markers vascular endothelial growth factor receptor-2 (VEGFR2), von Willebrand factor (vWF), and fibrosis marker α-smooth muscle actin (α-SMA) were observed by immunohistochemistry. Sirius Red staining was also used to determine liver fibrosis. Correlations between levels of intrahepatic angiogenesis and Child-Pugh classes, liver fibrosis degree, and portal vein pressure were examined. We also analyzed the relationship between levels of intrahepatic angiogenesis and complications of PH, including esophageal varices (EV), ascites, and hypersplenism.

RESULTS

Correlation was observed between the levels of VEGFR2 (r = 0.590, P < 0.01), vWF (r = 0.524, P < 0.01) in tissue, and Child-Pugh classes. Significant correlations were observed between levels of VEGFR2 and α-SMA (r = 0.710, P < 0.01), VEGFR2 and Sirius Red (r = 0.841, P < 0.01), vWF and α-SMA (r = 0.768, P < 0.01), and vWF and Sirius Red (r = 0.825, P < 0.01). Patients with hepatic venous pressure gradient (HVPG) ≥12 mmHg showed higher levels of VEGFR2 and vWF expression compared to those with (HVPG) <12 mmHg (2.60 ± 1.28% vs. 1.09 ± 0.73%; 5.85 ± 2.45% vs. 2.31 ± 1.34%, P < 0.01), respectively. Moreover, complications of PH, including size of esophageal varices (P < 0.01), presence of ascites (P < 0.01), and spleen volume (P < 0.01) were significantly affected by the levels of intrahepatic angiogenesis.

CONCLUSION

Intrahepatic angiogenesis increases PH in hepatitis B patients with cirrhosis. The study provides the potential ways to intervene in the progresses for therapeutic benefits in cirrhosis and PH.

Effects of raloxifene on portal hypertension and hepatic encephalopathy in cirrhotic rats

Raloxifene, a selective estrogen receptor modulator, has been used extensively for osteoporosis. In addition to the effect of osteoporosis treatment, emerging evidences show that raloxifene affects the vascular function in different tissues. Cirrhosis is characterized with portal hypertension and complicated with hepatic encephalopathy. Portal hypertension affects portal-systemic shunt which leads to hepatic encephalopathy that the vascular modulation might influence severity of hepatic encephalopathy. Herein, we evaluated the impact of raloxifene on bile duct ligation (BDL)-induced cirrhotic rats. The female Sprague-Dawley rats received BDL plus ovariectomy or sham-operation. Four weeks later, rats were divided into 2 subgroups respectively to receive of raloxifene (10mg/kg/day) or saline (vehicle) for 14 days. On the 43th day, motor activities and hemodynamic parameters were measured. Hepatic and vascular mRNA and protein expressions were determined. The histopathological change of liver was examined. We found that the liver biochemistry, ammonia level and motor activity were similar between cirrhotic rats with or without raloxifene administration. The hemodynamic parameters were not significantly different except that raloxifene reduced portal venous inflow. Raloxifene exacerbated hepatic fibrosis and up-regulated hepatic endothelin-1 and cyclooxygenase 2 protein expressions. In addition, raloxifene modulated the mRNA expressions of endothelial nitric oxide synthase, cyclooxygenase and endothelin-1 in the superior mesenteric artery and collateral vessel. In conclusion, raloxifene aggravates hepatic fibrosis and decreases portal venous inflow in cirrhotic rats without adversely affecting portal hypertension and hepatic encephalopathy. The modulation of hepatic and vascular endothelin-1, endothelial nitric oxide synthase and cyclooxygenase expressions may play a role in the mechanism.

A conceptual and practical approach to haemostasis in paediatric liver disease

Children with liver disease can develop severe bleeding episodes and thrombosis. Liver failure usually results in decreased levels of procoagulant and anticoagulant factors. Additional risk factors, including changes in vascular flow and endothelial function, are of importance for the development of bleeding or thrombosis in individual vascular beds. Detailed studies of haemostatic disturbances in the setting of paediatric liver disease are sparse and extrapolation from adult studies is common. The spectrum of liver diseases and the haemostatic system differs between children and adults. Specific paediatric liver diseases are reported to have more distinctive effects on haemostasis and the risk of bleeding and/or thrombosis.

CONCLUSION

we propose a model regarding haemostasis in paediatric liver disease, taking into account a number of specific variables and mechanisms, as well as the type of liver disease, which will provide a framework for clinical decision-making in these complex patients.

Contrast-enhanced ultrasonography could be a non-invasive method for differentiating none or mild from severe fibrosis in patients with biopsy proven non-alcoholic fatty liver disease

OBJECTIVE

The gold standard for diagnosing fibrosis stage in non-alcoholic fatty liver disease (NAFLD) is liver biopsy. The aim of this study was to determine whether contrast-enhanced ultrasonography (CEUS) with transit time measurements could be a non-invasive alternative for differentiating none or mild from severe fibrosis in NAFLD patients. Various serum markers and clinical variables were also evaluated.

MATERIALS AND METHODS

Fifty-eight patients with NAFLD underwent CEUS prior to liver biopsy. All patients were also evaluated according to the Göteborg University Cirrhosis Index (GUCI), the AST-Platelet Ratio Index (APRI), the NAFLD fibrosis score, and the FIB-4 and BARD score.

RESULTS

The hepatic vein arrival time (HV) was shorter in patients with severe fibrosis (25.9 ± 4.8 vs 29.5 ± 4.7 s, p = 0.023), and the difference between the hepatic and portal vein (ΔHV-PV) was shorter (2.3 ± 2.8 vs 6.4 ± 2.8 s, p < 0.0001) while the difference in arrival time between the portal vein and hepatic artery (ΔPV-HA) arrival time was significantly longer (6.0 ± 2.2 vs 3.6 ± 1.6 s, p < 0.0001). The area under receiver operating characteristics curve values for HV, ΔHV-PV and ΔPV-HA to separate none or mild from severe fibrosis was 0.71, 0.83 and 0.84, respectively. The corresponding figures for GUCI, APRI, NAFLD fibrosis score, FIB-4 and BARD score were 0.93, 0.92, 0.86, 0.90 and 0.77, respectively.

CONCLUSIONS

CEUS and non-invasive scoring systems could exclude severe fibrosis in NAFLD patients.

Decompensated liver cirrhosis and neural regulation of mesenteric vascular tone in rats: role of sympathetic, nitrergic and sensory innervations

We evaluated the possible alterations produced by liver cholestasis (LC), a model of decompensated liver cirrhosis in sympathetic, sensory and nitrergic nerve function in rat superior mesenteric arteries (SMA). The vasoconstrictor response to electrical field stimulation (EFS) was greater in LC animals. Alpha-adrenoceptor antagonist phentolamine and P2 purinoceptor antagonist suramin decreased this response in LC animals more than in control animals. Both non-specific nitric oxide synthase (NOS) L-NAME and calcitonin gene related peptide (CGRP) (8-37) increased the vasoconstrictor response to EFS more strongly in LC than in control segments. Vasomotor responses to noradrenaline (NA) or CGRP were greater in LC segments, while NO analogue DEA-NO induced a similar vasodilation in both experimental groups. The release of NA was not modified, while those of ATP, nitrite and CGRP were increased in segments from LC. Alpha 1 adrenoceptor, Rho kinase (ROCK) 1 and 2 and total myosin phosphatase (MYPT) expressions were not modified, while alpha 2B adrenoceptor, nNOS expression and nNOS and MYPT phosphorylation were increased by LC. Together, these alterations might counteract the increased splanchnic vasodilation observed in the last phases of decompensated liver cirrhosis.

Acute Kidney Injury After Major Surgery: A Retrospective Analysis of Veterans Health Administration Data

BACKGROUND

Few trials of acute kidney injury (AKI) prevention after surgery have been conducted, and most observational studies focus on AKI following cardiac surgery. The frequency of, risk factors for, and outcomes after AKI following other types of major surgery have not been well characterized and may present additional opportunities for trials in AKI.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

3.6 million US veterans followed up from 2004 to 2011 for the receipt of major surgery (cardiac; general; ear, nose, and throat; thoracic; vascular; urologic; and orthopedic) and postoperative outcomes.

FACTORS

Demographics, health characteristics, and type of surgery.

OUTCOMES

Postoperative AKI defined by the KDIGO creatinine criteria, postoperative length of stay, end-stage renal disease, and mortality.

RESULTS

Postoperative AKI occurred in 11.8% of the 161,185 major surgery hospitalizations (stage 1, 76%; stage 2, 15%, stage 3 [without dialysis], 7%; and AKI requiring dialysis, 2%). Cardiac surgery had the highest postoperative AKI risk (relative risk [RR], 1.22; 95% CI, 1.17-1.27), followed by general (reference), thoracic (RR, 0.92; 95% CI, 0.87-0.98), orthopedic (RR, 0.70; 95% CI, 0.67-0.73), vascular (RR, 0.68; 95% CI, 0.64-0.71), urologic (RR, 0.65; 95% CI, 0.61-0.69), and ear, nose, and throat (RR, 0.32; 95% CI, 0.28-0.37) surgery. Risk factors for postoperative AKI included older age, African American race, hypertension, diabetes mellitus, and, for estimated glomerular filtration rate < 90mL/min/1.73m(2), lower estimated glomerular filtration rate. Participants with postoperative AKI had longer lengths of stay (15.8 vs 8.6 days) and higher rates of 30-day hospital readmission (21% vs 13%), 1-year end-stage renal disease (0.94% vs 0.05%), and mortality (19% vs 8%), with similar associations by type of surgery and more severe stage of AKI relating to poorer outcomes.

LIMITATIONS

Urine output was not available to classify AKI; cohort included mostly men.

CONCLUSIONS

AKI was common after major surgery, with similar risk factor and outcome associations across surgery type. These results can inform the design of clinical trials in postoperative AKI to the noncardiac surgery setting.

High-resolution Manometry Findings in Patients After Sclerotherapy for Esophageal Varices

Background/Aims

Endoscopic therapy for esophageal varices may lead to esophageal dysmotility. High-resolution manometry is probably the more adequate tool to measure esophageal motility in these patients. This study aimed to evaluate esophageal motility using high resolution manometry following eradication of esophageal varices by endoscopic sclerotherapy.

Methods

We studied 21 patients (11 women, age 52 [45–59] years). All patients underwent eradication of esophageal varices with endoscopic sclerotherapy and subsequent high resolution manometry.

Results

A significant percentage of defective lower esophageal sphincter (basal pressure 14.3 [8.0–20.0] mmHg; 43% hypertonic) and hypocontractility (distal esophageal amplitude 50 [31–64] mmHg; proximal esophageal amplitude 40 [31–61] mmHg; distal contractile integral 617 [403–920] mmHg · sec · cm; 48% ineffective) was noticed. Lower sphincter basal pressure and esophageal amplitude correlated inversely with the number of sessions (P < 0.001). No manometric parameter correlated with symptoms or interval between last endoscopy and manometry.

Conclusions

Esophageal motility after endoscopic sclerotherapy is characterized by: (1) defective lower sphincter and (2) defective and hypotensive peristalsis. Esophageal dysmotility is associated to an increased number of endoscopic sessions, but manometric parameters do not predict symptoms.

Long-term efficacy of subtotal splenectomy due to portal hypertension in cirrhotic patients

Background

Portal hypertension (PHT) requires invasive measures to prevent rupture and bleeding of esophagogastric varices; however, the long-term results of subtotal splenectomy plus fixation of the retrosternal omentum majus (SSFROM) have not been reported. Specifically, the advantages and disadvantages of surgery that preserves the spleen and the long-term hematologic effects have not been described.

Study design

Our studies relating to SSFROM commenced in February 1999. As of April 2014 we have performed 256 subtotal splenectomies The records of 65 patients with PHT who underwent SSFROM were reviewed retrospectively.

Results

Four patients died within 4 years of surgery, with a 4-year survival rate of 94 %; the 11-year survival rate was 60 %. Eleven patients (17 %) had re-bleeding from esophagogastric varices. The white blood cell and platelet counts were higher 6 and 11 years post-operatively compared with pre-operative values (P < 0.01). Portal venous diameter, portal venous flow volume, splenic artery flow volume, as well as splenic length, thickness, and average cross-sectional areas were shown to be significantly constricted or decreased (P < 0.01). The proportion of serum CD3+ T cells, CD4+ T cells, and CD8+ T cells was increased (P < 0.01), while the serum levels of macrophage colony-stimulating factor and granulocyte-macrophage colony-stimulating factor were significantly decreased (P < 0.01). There was no significant change in the serum levels of IgA, IgM, IgG, and Tuftsin (P > 0.05). DSA demonstrated that 15 cases formed collateral circulations between the portal vein and superior vena cava.

Conclusion

SSFROM provide long-term hemostasis for esophagogastric variceal bleeding in PHT and corrected hypersplenism. SSFROM is an effective treatment for patients with PHT in whom long-term survival is expected.

Portal hypertension induced by congenital hepatic arterioportal fistula: Report of four clinical cases and review of the literature

Intrahepatic arterioportal fistula (IAPF) can be caused by many secondary factors. We report four cases of portal hypertension that were eventually determined to be caused by congenital hepatic arterioportal fistula. The clinical manifestations included ascites, variceal hemorrhage and hepatic encephalopathy. Computed tomography scans from all of the patients revealed the early enhancement of the portal branches in the hepatic arterial phase. All patients were diagnosed using digital subtraction angiography (DSA). DSA before embolization revealed an arteriovenous fistula with immediate filling of the portal venous radicles. All four patients were treated with interventional embolization. The four patients remained in good condition throughout follow-up and at the time of publication. IAPF is frequently misdiagnosed due to its rarity; therefore, clinicians should consider IAPF as a potential cause of non-cirrhotic portal hypertension.

Role of vaptans in the management of hydroelectrolytic imbalance in liver cirrhosis

Ascites and hyponatremia are the most common complications in patients with liver cirrhosis and develop as a consequence of a severe impairment of liver function and portal hypertension. Increasing evidences support the central role of renal function alterations in the pathogenesis of hydroelectrolytic imbalances in cirrhotic patients, thus implying a dense cross-talk between liver and kidney in the systemic and splanchnic vascular homeostasis in such subjects. Since Arginin Vasopressin (AVP) hyperincretion occurs at late stage of cirrhosis and plays an important role in the development of refractory ascites, dilutional hyponatremia and finally hepato-renal syndrome, selective antagonists of AVP receptors V₂ (vaptans) have been recently introduced in the therapeutic algorithm of advanced cirrhotic patients. Despite the promising results of earlier phase-two studies, randomized controlled trials failed to find significant results in terms of efficacy of such drugs both in refractory ascites and hyponatremia. Moreover, concerns on their safety profile arise, due to the number of potentially severe side effects of vaptans in the clinical setting, such as hypernatremia, dehydration, renal impairment, and osmotic demyelination syndrome. More robust data from randomized controlled trials are needed in order to confirm the potential role of vaptans in the management of advanced cirrhotic patients.