Influence of esophageal varices and spontaneous portal-systemic shunts on postprandial splanchnic hemodynamics

Doppler ultrasound, a noninvasive tool for the study of mesenteric arterial flow in systemic sclerosis: a cross-sectional study of a patient cohort with review and meta-analysis of the literature

Gastrointestinal involvement (GI) is a frequent and troublesome complication of systemic sclerosis (SSc), whose etiology is poorly understood, though it is hypothesized that autoimmunity and progressive vasculopathy may play a role. Vasculopathy is considered one of the main pathogenetic pathways responsible for many of the clinical manifestations of SSc, and, therefore, studying the principal splanchnic vessels (i.e., superior mesenteric artery-SMA and inferior mesenteric artery-IMA) with Doppler Ultrasound (DUS) may provide further insights into measuring the progression of vasculopathy, evaluating its possible association with SSc GI symptoms, and determining whether it plays a role in the development or severity of SSc GI disease. A cohort of SSc patients consecutively recruited underwent DUS examination, and associations with GI (UCLA-GIT 2.0 questionnaire) and extraintestinal SSc characteristics were evaluated. Semiquantitative DUS parameters (resistive index-RI and pulsatility index-PI), were applied for splanchnic vessel assessment in SSc patients and healthy subjects (HS). Moreover, a review and meta-analysis of the literature to understand which the values of the main semiquantitative DUS parameters (RI and PI) are both in SSc patients and HS has been conducted. Seventy-eight patients completed DUS examinations and clinical assessments. 30 (39%) were classified as diffuse cutaneous SSc (dcSSC), 35 (45%) as limited cutaneous SSc (lcSSc) and 13 (17%) as sine scleroderma. A significant difference was found both for SMA RI (p for trend = 0.032) and SMA PI (p for trend = 0.004) between patients with sine scleroderma, lcSSc and dcSSc, with lower values observed in the sine scleroderma and lcSSc groups. IMA RI and PI were significantly correlated with GI symptoms such as fecal incontinence (ῥ - 0.33, p = 0.008 and ῥ - 0.30, p = 0.021, respectively). By multivariate analysis, significant associations were confirmed between SMA RI and SMA PI and mRSS (β 0.248, p = 0.030 and β 2.995, p = 0.004, respectively) and with bosentan (β 0.400, p = 0.003 and β 3.508, p = 0.001, respectively), but not with anticentromere antibody (ACA). No significant differences were found between the weighted median values of SMA RI and SMA PI of SSc patients compared to those of HS that were derived from the meta-analysis of the literature (p = 0.72 and p = 0.64, respectively). This cross-sectional study confirms that the splanchnic vasculature of SSc patients can noninvasively been studied with DUS. Vascular splanchnic involvement correlates with the presence and/or severity of specific clinical features in SSc, including GI. Larger and prospective studies are needed to confirm these preliminary observations and to examine the role of DUS in SSc-risk stratification and GI progression and to obtain definitive data regarding both HS and SSc patients splanchnic DUS parameters.

A systematic review and meta-analysis of portal vein morphometry in pediatric and adult populations: Drawing the line between normal and abnormal findings

PURPOSE

The morphometry of the hepatic portal vein is of clinical importance, particularly in pre-operative assessments, surgical management, and diagnoses of liver conditions. This systematic review and meta-analysis aimed to characterize the morphometry of the normal portal vein in both pediatric and adult patients.

METHODS

The study, conducted using the PRISMA guidelines and registered with PROSPERO, utilized the MEDLINE, EMBASE, SCOPUS and Web of Science databases up to May 2020, and updated to May 2023. All studies reporting extractable data on diameter, length, and cross-sectional area (CSA) of the main, left, and right portal veins (PV, LPV, RPV, respectively) were included. The AQUA Tool was used to assess the quality of the included studies. Data analysis included subgroup analyses based on geographical location, sex, age, and imaging modality.

RESULTS

A total of 122 studies with 11,637 subjects were eligible for inclusion. Overall, the pooled mean diameter of the PV (PVD) was 10.09 mm (95% CI: 9.56-10.62). Significant differences in diameter were found between pediatric (6.60 mm; 95% CI: 5.38-7.82) and adult (10.72 mm; 95% CI: 10.25-11.19) subjects. Additionally, there was a significantly larger PVD measurement from computed tomography (CT) than other imaging modalities: CT, 13.28 mm (95% CI: 11.71-14.84); magnetic resonance imaging (MRI), 10.50 mm (95% CI: 9.35-11.66) and ultrasound (US), 9.81 mm (95% CI: 9.47-10.16). The mean diameters of the LPV and RPV were 8.27 mm (95% CI: 6.78-9.77) and 8.33 mm (95% CI: 6.70-9.95), respectively. Mean PV length in adults is 48.63 mm (95% CI: 35.63-61.64). Mean CSA of the PV was 1.09 cm2.

CONCLUSIONS

The study obtained aim to improve the understanding of portal vein anatomy, especially with relevance to surgical interventions of the liver in both pediatric and adult patients. Measurements from ultrasound imaging closely approximates the generated pooled PVD mean for pediatric and adult patients. CT imaging, however, significantly exceeded the established 13 mm threshold for adults. For pediatric patients, a threshold of 8 mm is proposed as a diagnostic upper limit for a normal PVD. Although not significant, the PVD decreased from the portal confluence towards its bifurcation.

Anti-VEGFR agents ameliorate hepatic venous dysregulation/microcirculatory dysfunction, splanchnic venous pooling and ascites of NASH-cirrhotic rat

BACKGROUND & AIMS

Antivascular endothelial growth factor receptor (VEGFR) agents improve hepatic fibrosis and portal hypertension in cirrhosis. Detail interactions among recruited/activated leucocytes, hepatic angiogenesis and fibrogenesis, splanchnic blood pooling, decreased hepatic veins to fluctuated splanchnic blood volume (hepatic venous dysregulation), portal hypertensive syndrome and ascites have never explored in cirrhosis. Our study used two anti-VEGFR agents - brivanib and sorafenib - to elucidate the relationship between above abnormalities of nonalcoholic steatohepatitis (NASH)-cirrhotic rats.

MATERIALS AND METHODS

NASH-cirrhotic rats received 2-week brivanib, sorafenib or vehicle (NASH-cirrhotic+briv, NASH-cirrhotic+soraf and NASH-cirrhotic rats) were included for various measurements.

RESULTS

In comparison with NASH-cirrhotic rats, significant decreased plasma VEGF, fibroblast growth factor, platelet-derived growth factor, hepatic tumour necrosis factor (TNFα), IL-1β, IL-6, IL-17 were accompanied by decreased leucocyte mass/activity ((99 m) Tc-phytate and (18) F-FDG SPECT/PET/CT scans), hepatic leucocytes recruitment/microvascular density (fluorescence-enhanced intravital microscopy) and hydroxyproline content, and increased hepatic blood flow in NASH-cirrhotic+briv and NASH-cirrhotic+soraf rats. In addition, increased hepatic microvasculatures compliance-related improved buffering effect of portal vein to acute mannitol infusion was associated with decreased circulating nitric oxide and aldosterone, plasma volume expansion (dye dilution method), splanchnic blood pooling ((99 m) Tc-RBC SPECT/PET/CT scans), peripheral hypotension, portal hypertension and ascites in brivanib and sorafenib-treated NASH-cirrhotic rats.

CONCLUSION

Besides antifibrotic, antiangiogenic and portal hypertensive effects, chronic antagonism of anti-VEGFR with brivanib and sorafenib improves hepatic blood flow, hepatic venous dysregulation, inhibits leucocytes recruitment/activation, splanchnic blood pooling and ascites formation in NASH-cirrhotic rats. Thus, brivanib and sorafenib might be ideal therapeutic agents in cirrhotic patients suffering from severe haemodynamic disarrangement and ascites.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Dynamic postprandial hepatic stiffness augmentation assessed with MR elastography in patients with chronic liver disease

OBJECTIVE

MR elastography (MRE) is an MRI-based technique for quantitatively assessing tissue stiffness by studying shear wave propagation through tissue. The goal of this study was to test the hypothesis that hepatic MRE performed before and after a meal will result in a postprandial increase in hepatic stiffness among patients with hepatic fibrosis because of transiently increased portal pressure.

SUBJECTS AND METHODS

Twenty healthy volunteers and 25 patients with biopsyproven hepatic fibrosis were evaluated. Preprandial MRE measurements were performed after overnight fasting. A liquid test meal was administered, and 30 minutes later a postprandial MRE acquisition was performed. Identical imaging parameters and analysis regions of interest were used for pre- and postprandial acquisitions.

RESULTS

The results in the 20 subjects without liver disease showed a mean stiffness change of 0.16 ± 0.20 kPa (range, -0.12 to 0.78 kPa) or 8.08% ± 10.33% (range, -5.36% to 41.7%). The hepatic stiffness obtained in the 25 patients with hepatic fibrosis showed a statistically significant increase in postprandial liver stiffness, with mean augmentation of 0.89 ± 0.96 kPa (range, 0.17-4.15 kPa) or 21.24% ± 14.98% (range, 7.69%-63.3%).

CONCLUSION

MRE-assessed hepatic stiffness elevation in patients with chronic liver disease has two major components: a static component reflecting structural change or fibrosis and a dynamic component reflecting portal pressure that can increase after a meal. These findings will provide motivation for further studies to determine the potential value of assessing postprandial hepatic stiffness augmentation for predicting the progression of fibrotic disease and the development of portal hypertension. The technique may also provide new insights into the natural history and pathophysiology of chronic liver disease.

Four-dimensional velocity mapping of the hepatic and splanchnic vasculature with radial sampling at 3 tesla: a feasibility study in portal hypertension

PURPOSE

To demonstrate the feasibility of PC-VIPR (Phase Contrast Vastly undersampled Imaging with Projection Reconstruction) for the depiction and hemodynamic analysis of hepatic and splanchnic vessels in patients with portal hypertension.

MATERIALS AND METHODS

Twenty-four cirrhotic patients (55.9 ± 10.4 years) were scanned using 5-point PC-VIPR for high spatial resolution imaging with large volume coverage at 3 Tesla (T) using a 32-channel body coil. Vessel segmentation and hemodynamic visualization included color-coded three-dimensional (3D) streamlines and particle traces. Segmentation quality was compared with contrast-enhanced multi-phase liver imaging. Flow pattern analysis was performed in consensus of three readers. The MELD score was calculated to estimate disease severity and was correlated to image quality.

RESULTS

Good to excellent visualization quality was achieved in 23/24 cases. All arterial vessels and 144/168 vessels of the portal venous (PV) circulation were unambiguously identified. No correlation with the MELD score was found. Eight of 148 vessels of the PV circulation demonstrated reverse (hepatofugal) flow. Hepatofugal flow in small tributaries to PV flow were present in three cases despite hepatopetal flow in the PV.

CONCLUSION

This feasibility study demonstrates the feasibility of PC-VIPR for simultaneous morphological and hemodynamic assessment of the hepatic and splanchnic vasculature in cirrhosis and portal hypertension. Future studies with quantitative analyses are warranted.

The extent of the collateral circulation influences the postprandial increase in portal pressure in patients with cirrhosis

BACKGROUND

In cirrhosis, repeated flares of portal pressure and collateral blood flow provoked by postprandial hyperaemia may contribute to variceal dilation and rupture.

AIM

To examine the effect of the extent of the collateral circulation on the postprandial increase in portal pressure observed in cirrhosis.

PATIENTS AND METHODS

The hepatic venous pressure gradient (HVPG), hepatic blood flow and azygos blood flow were measured in 64 patients with cirrhosis before and after a standard liquid meal.

RESULTS

Peak increases in HVPG (median+14.9%), hepatic blood flow (median+25.4%), and azygos blood flow (median+32.2%) occurred at 30 min after the meal. Compared with patients with marked postprandial increase in HVPG (above the median, n = 32), those showing mild (<15%, n = 32) increase in HVPG had a higher baseline azygos flow (p<0.01) and underwent a greater postprandial increase in azygos flow (p<0.02). Hepatic blood flow increased similarly in both groups. Postprandial increases in HVPG were inversely correlated (p<0.001) with both baseline azygos flow (r = -0.69) and its postprandial increase (r = -0.72). Food intake increased nitric oxide products in the azygos (p<0.01), but not in the hepatic vein. Large varices (p<0.01) and previous variceal bleeding (p<0.001) were more frequent in patients with mild increase in HVPG.

CONCLUSIONS

Postprandial hyperaemia simultaneously increases HVPG and collateral flow. The extent of the collateral circulation determines the HVPG response to food intake. Patients with extensive collateralisation show less pronounced postprandial increases in HVPG, but associated with marked flares in collateral flow. Collateral vessels preserve their ability to dilate in response to increased blood flow.

Circadian rhythm of fasting and postprandial portal blood flow in cirrhosis

OBJECTIVE

To examine the relationship of both the unstimulated and the postprandial portal blood flow (PVF) to the time of day and to determine its intra-individual reproducibility over time in patients with liver cirrhosis.

MATERIAL AND METHODS

In 24 cirrhotic patients, 27 PVF measurements were performed during 24 h on day 0 and day 7 using Doppler ultrasound. Three standard liquid meals were given orally. On day 7, the baseline hepatic venous pressure gradient (HVPG) was also measured.

RESULTS

Circadian area under the time curve of PVF was highly reproducible within individuals (r=0.959, p<0.001). It did not correlate with HVPG. Cosinor analysis showed a significant circadian rhythm of PVF (acrophase at 11:44 and amplitude of 9.44%). Maximal postprandial increase in PVF was significantly higher in the morning than at noon or in the evening.

CONCLUSIONS

PVF is subject to a circadian rhythm and postprandial portal hyperemia shows a diurnal variability. Both are highly reproducible.

Correlation between ultrasonographic and pathologic diagnosis of liver fibrosis due to chronic virus hepatitis

AIM: To evaluate the validity of ultrasonographic and pathologic diagnosis of liver fibrosis in patients with chronic viral hepatitis.

METHODS: The liver fibrosis status in 324 patients was evaluated by both needle biopsy and ultrasonography. Liver fibrosis was divided into S0 -S4 stages. S4 stage was designated as definite cirrhosis. The ultrasonographic examination included qualitative variables, description of liver surface and parenchyma, and quantitative parameters, such as diameter of vessels, blood flow velocity and spleen size.

RESULTS: Ultrasonographic qualitative description of liver surface and parenchyma was related with the severity of fibrosis. Among the quantitative ultrasonographic parameters, cut-off value of spleen length (12.1 cm) had a sensitivity of 0.600 and a specificity of 0.753 for diagnosis of liver cirrhosis. The diameters of spleen (8 mm) and portal vein (12 mm) had a diagnostic sensitivity of 0.600 and 0.767, and a diagnostic specificity of 0.781 and 0.446, respectively. The diagnostic accuracy for liver cirrhosis was moderately satisfactory, and the negative predictive values of these parameters reached near 0.95.

CONCLUSION: Ultrasonography can predict the degree of liver fibrosis or cirrhosis. A single ultrasonographic parameter is limited in sensitivity and specificity for the diagnosis of early cirrhosis. The presence or absence of liver cirrhosis in patients with chronic virus hepatitis can be detected using 2 or 3 quantitative and qualitative parameters, especially the length of spleen, the diameter of spleen vein and echo pattern of liver surface.

Postprandial splanchnic haemodynamic changes in patients with liver cirrhosis and patent paraumbilical vein

OBJECTIVE

The haemodynamic changes induced by a meal on collateral vessels in portal hypertensive cirrhotic patients are not well characterized. We aimed to study the postprandial modifications of splanchnic circulation in patients with a patent paraumbilical vein (PUV).

METHODS

We studied 10 cirrhotic patients with patent PUV and 10 matched cirrhotic patients without PUV, by using echo colour Doppler at baseline and 15, 30 and 45 min after a standard mixed liquid meal (400 ml; 600 kcal). Calibre and blood flow velocities of the superior mesenteric artery, portal vein and PUV were obtained; congestion index of portal vein, portal blood flow, paraumbilical blood flow and effective portal liver perfusion were calculated; intrahepatic and intrasplenic arterial resistance and pulsatility indexes were recorded.

RESULTS

We observed a postprandial splanchnic hyperaemia (superior mesenteric artery and portal vein blood flow increased after the meal in both groups; ANOVA P < 0.05), with no changes of hepatic impedance. In PUV patients, PUV constricted significantly postprandially, maximally at 30 min (calibre -17.5 +/- 7.0%; P = 0.003). Intrasplenic impedance, which may reflect portal pressure, increased, maximally at 30 min (pulsatility index +22.6 +/- 27.0%; P = 0.01), and inversely correlated with PUV vasoconstriction (R = 0.75, P = 0.01). In non-PUV patients intrasplenic impedance did not change. Portal liver perfusion increased similarly in both groups.

CONCLUSIONS

PUV constricts after the meal, and this vasoconstriction is associated with an increase of splenic impedance which may indicate the postprandial increase of portal pressure observed in cirrhosis. The increase in postprandial portal liver perfusion in the PUV group is allowed by a paradox constriction of the collateral vessel.

Different haemodynamic effects of a single dose of long-acting isosorbide-5-mononitrate in healthy subjects and patients with cirrhotic portal hypertension

BACKGROUND

The action pathways of nitrates are hypothesised to be deranged in cirrhosis.

AIM

In order to confirm it, the acute haemodynamic effects of isosorbide-5-mononitrate in cirrhotic patients and controls was investigated.

PATIENT

Nine cirrhotics and nine healthy controls.

METHODS

Evaluation in the fasting state, 90 min after isosorbide-5-mononitrate or placebo (double-blind on two different days) and then 30 and 120 min after eating a standard meal. Various systemic and splanchnic haemodynamic parameters, including arterial impedance, assessed as Doppler pulsatility index, were measured.

RESULTS

isosorbide-5-mononitrate reduced arterial pressure and increased heart rate and mesenteric pulsatility index both in controls and in cirrhotics, whereas the following parameters behaved differently in the two groups (P < 0.05): hepatic pulsatility index decreased (-9%) and the portal velocity increased (+13%) in controls, whereas hepatic pulsatility increased (+18%) and portal velocity decreased (-18%) in cirrhotics. The two groups presented a similar pattern of changes in most variables under placebo after a meal. In controls, the administration of isosorbide-5-mononitrate blunted the postprandial mesenteric vasodilation and related changes in splanchnic and systemic circulation, expected at 30 min, in comparison to those observed under placebo. In cirrhotics, instead, the postprandial pattern was similar under placebo and isosorbide-5-mononitrate.

CONCLUSIONS

The acute administration of isosorbide-5-mononitrate produces different haemodynamic effects in healthy and diseased livers, both in the fasting state and after a meal, consistent with the hypothesis of a deranged response of the intrahepatic microcirculation to nitrates in cirrhosis.

Effect of Levovist on splanchnic hemodynamics in cirrhotic patients

This study was aimed to assess the effect of Levovist on Doppler parameters of splanchnic hemodynamics. A total of 12 patients with cirrhosis and 12 healthy subjects underwent Doppler ultrasound (US) examination of the portal vein and of the hepatic, splenic and superior mesenteric arteries before, 5 to 8 and 12 to 15 min after the start of an 8-min long IV infusion of 2.5 g of Levovist. Mean velocity and mean diameter were calculated for the portal vein. Resistance index was determined for the arteries. A significant increase of resistance index was observed in the hepatic (0.80 +/- 0.07 vs. 0.71 +/- 0.06; p < 0.01) and splenic arteries (0.72 +/- 0.06 vs. 0.64 +/- 0.06; p < 0.01) 5 to 8 min after contrast agent injection in patients with cirrhosis, but not in controls. Neither portal vein diameter nor portal flow mean velocity changed during the test in both controls and cirrhotic patients. This effect might be related to a selective trapping of microbubbles in the altered hepatic and splenic microvasculature in patients with cirrhosis rather than being artefactual. It might have implications on harmonic imaging US protocols designed to image the cirrhotic liver in the early arterial phase.

Intrahepatic spontaneous retrograde portal flow in patients with cirrhosis of the liver: reversal by food intake

OBJECTIVE

The purpose of our study was to assess whether intrahepatic spontaneous retrograde portal flow in patients with cirrhosis of the liver can be reversed to a normal portal venous flow by food intake.

CONCLUSION

Of the 18 cirrhotic patients with intrahepatic spontaneous retrograde portal flow, 16 (89%) showed a marked change in portal flow direction after food intake. This evidence strongly suggests that intrahepatic spontaneous retrograde portal flow may be reversible. Furthermore, this finding implies that regular food intake may be important in the maintenance of effective hepatic blood flow in cirrhotic patients.