Evaluation of postprandial hyperemia in superior mesenteric artery and portal vein in healthy and cirrhotic humans: an operator-blind echo-Doppler study

In an operator-blind design, we used an echo-Doppler duplex system to examine superior mesenteric artery and portal vein hemodynamics on two consecutive mornings in 12 fasting cirrhotic patients and 12 matched controls, randomized to a standardized 355 kcal mixed-liquid meal vs. water. Cross-sectional area and mean velocity were recorded from the portal vein and superior mesenteric artery at 30 min intervals, from 0 min to 150 min after ingestion. Flows were calculated. Pulsatility index, an index related to vascular resistance, was obtained for the mesenteric artery. Baseline flows did not differ between cirrhotic patients and control patients, but pulsatility index was reduced in the cirrhotic subjects. Maximal postprandial hyperemia was attained at 30 min. Cirrhotic patients showed a blunted hyperemic response to food. In normal controls, portal vein area increased significantly after the meal from 30 min to 150 min, whereas in cirrhotic patients a significant difference occurred only at 30 min. Pulsatility index in both groups was significantly reduced after eating, and this reduction persisted up to 150 min. No changes after ingestion of water were observed. Echo-Doppler was very sensitive in detecting postprandial splanchnic hemodynamic changes and differences between cirrhotic patients and normal subjects. Mesenteric artery pulsatility index was more sensitive than flow in detecting baseline hemodynamic differences. In cirrhotic patients, portal postprandial hyperemia was mainly related to the increase in mean velocity.     

Role of echo Doppler ultrasonography in the evaluation of postprandial hyperemia in cirrhotic patients

AIM： TO assess the role of echo-Doppler ultrasonography in postprandial hyperemia in cirrhotic patients by comparing the results with the hepatic vein catheterization technique.
METHODS： Patients with cirrhosis, admitted to the portal hemodynamic laboratory were included into the study. After an overnight fast, echo-Doppler ultrasonography （basal and 30 min after a standard meal） and hemodynamic studies by hepatic vein catheterization （basal, 15 min and 30 min after a standard meal） were performed. Ensure Plus （Abbot Laboratories, North Chicago, IL） was used as the standard liquid meal. Correlation analysis of the echo- Doppler and hepatic vein catheterization measurements were done for the basal and postprandial periods.
RESULTS： Eleven patients with cirrhosis （5 Child A, 4 Child B, 2 Child C） were enrolled into the study. After the standard meal, 8 of the 11 patients showed postprandial hyperemia with increase in portal blood flow, portal blood velocity and hepatic venous pressure gradient. Hepatic venous pressure gradient in the postprandial period correlated positively with postprandial portal blood velocity （r = 0.8, P 〈 0.05） and correlated inversely with postprandial superior mesenteric artery pulsatility index （r = -1, P 〈 0.01）.
CONCLUSION： Postprandial hyperemia can be efficiently measured by echo-Doppler ultrasonography and the results are comparable to those obtained with the hemodynamic studies.     

Different hemodynamic patterns of alcoholic and viral endstage cirrhosis: analysis of explanted liver weight, degree of fibrosis and splanchnic Doppler parameters

OBJECTIVE: In cirrhosis, portal hemodynamics is usually considered independently of the disease etiology. The objective of this study was to investigate the role of the etiology of liver disease on the relationship between liver blood flow and liver pathology in endstage cirrhosis. MATERIAL AND METHODS: Portal blood velocity and volume, congestion index of the portal vein, and hepatic and splenic pulsatility indices were evaluated with echo-Doppler in cirrhotic patients immediately before liver transplantation. When a patent paraumbilical vein was present, its blood flow was measured and effective portal liver perfusion was calculated as portal blood flow minus paraumbilical blood flow. The hemodynamic parameters were correlated with liver weight and the pattern of the liver fibrosis morphometrically assessed in explanted livers. A total of 131 patients with alcoholic or viral cirrhosis were included in the study. RESULTS: In alcoholic cirrhosis, liver weight was higher than that in viral disease (1246+/-295 g versus 1070+/-254 g, p=0.001), portal liver perfusion per gram of liver tissue was lower (0.49+/-0.36 ml g(-1) min(-1) versus 0.85+/-0.56 ml g(-1) min(-1), p=0.004) and hepatic pulsatility indices were higher (1.45+/-0.31 versus 1.26+/-0.30, p=0.018). The degree of liver fibrosis was similar in alcoholic and viral cirrhosis (11.7+/-5.5% versus 11.0+/-4.4%, p=NS). An inverse relationship between liver weight and Child-Pugh score was disclosed in viral (p<0.001) but not in alcoholic disease. CONCLUSIONS: A different hemodynamic pattern characterizes the advanced stage of cirrhosis of alcoholic and viral origin. A more severe alteration of intrahepatic portal perfusion, probably coexisting with a more severe hepatocyte dysfunction, and a higher liver weight can be detected in alcoholic cirrhosis.     

Superior mesenteric artery impedance in chronic liver diseases: relationship with disease severity and portal circulation

Objective: The increase of splanchnic blood flow volume in liver cirrhosis is attributed to decreased arterial resistance. The aim of this study was to noninvasively investigate superior mesenteric artery impedance in patients with chronic liver diseases and to assess its relationship with portal hemodynamics and with clinical parameters.
Methods: Superior mesenteric artery (SMA) pulsatility (SMA-PI) and resistance (SMA-RI) indices and portal vein flow parameters (velocity, volume, and congestion index) were measured by duplex-Doppler ultrasound in 14 patients with chronic hepatitis, in 73 cirrhotics, in 30 liver transplant recipients, and in 31 control subjects.
Results: SMA-PI significantly differed among the five groups (   p < 0.0001  ), being lower in cirrhotics (2.55 ± 0.70) and transplanted patients (2.77 ± 0.69) than in chronic hepatitis (3.28 ± 0.57) and control subjects (3.42 ± 0.92). SMA-PI was lower in ascitic cirrhosis (2.40 ± 0.71) than in compensated cirrhosis (2.71 ± 0.70) (   p < 0.01  ) and in cirrhotics with large varices (2.30 ± 0.67) than in those without varices (2.75 ± 0.65) (   p < 0.05  ). Moreover SMA-PI correlated with numeric Child-Pugh score (  r =−0.28  ) and portal vein congestion index (  r =−0.36  ).
Conclusion: Hyperdynamic splanchnic circulation, noninvasively assessed by a decrease of mesenteric artery impedance, occurs in cirrhosis since the early stage of the disease and tends to worsen in relation to liver failure and the severity of portal hypertension. Furthermore, the persistent SMA-PI decrease in transplant recipients suggests a consistent contribution to this circulatory alteration from a patent portosystemic collateral circulation.     

Postprandial middle cerebral arterial vasoconstriction in cirrhotic patients. A placebo, controlled evaluation

BACKGROUND/AIMS: The objective of this study was to determine whether cerebral arterial vasoconstriction occurs in relation to postprandial splanchnic blood pooling in cirrhotic patients. METHODS: The pulsatility and the resistive indexes and blood flow in the middle cerebral artery were measured by magnetic resonance imaging in 21 cirrhotics and 14 controls. These measurements were repeated 30 min after ingestion of a 400 kcal liquid meal or placebo. Seven controls and 14 patients received the meal, and seven controls and seven patients received placebo. RESULTS: In the fasting conditions, cirrhotics had a greater pulsatility index (0.81 +/- 0.10 vs. 0.67 +/- 0.05, P < 0.001) and a greater resistive index (0.61 +/- 0.04 vs. 0.53 +/- 0.04, P < 0.001) and a lower blood flow (127 +/- 42 ml/min vs. 167 +/- 37 ml/min, P < 0.03) in the middle cerebral artery compared with controls. Meal ingestion significantly increased the pulsatility index (P < 0.03) and the resistive index (P < 0.01) and decreased blood flow (P < 0.03) in the middle cerebral artery in cirrhotics but not in controls. In contrast, placebo ingestion had no effect on the hemodynamic parameters in the middle cerebral artery in the two groups. CONCLUSIONS: Results support the hypothesis that middle cerebral arterial vasoconstriction seen in cirrhotic patients is one of the cerebral artery's homeostatic responses to underfilling of the splanchnic arterial circulation.     

Effect of the somatostatin analogue lanreotide on meal-stimulated portal blood flow in patients with liver cirrhosis

BACKGROUND: Lanreotide, a new long-acting somatostatin analogue, has been shown to inhibit the meal-stimulated increase of splanchnic blood flow in healthy volunteers. To date, similar data in patients with liver cirrhosis have not been available. We have examined the effect of lanreotide compared with placebo on meal-stimulated portal blood flow in patients with liver cirrhosis using Doppler ultrasound. METHODS: 20 cirrhotic patients (placebo n = 12, lanreotide n = 8) with proven portal hypertension were studied after an overnight fast. Lanreotide, at a dose of 100 microg/h, was infused intravenously over 7 h after a 1-hour basal period. In parallel to the intravenous infusion, a liquid test meal (Ensure plus, 1.5 kcal/min) was perfused for 7 h through an intraduodenal tube at a rate of 3 ml/min. Blood pressure, heart rate and portal vein blood flow (PVF, ml/min, Doppler technique) were determined at regular intervals. RESULTS: Baseline PVF amounted to 725 +/- 182 ml/min in the placebo and to 917 +/- 252 ml/min in the lanreotide group (n.s.). The meal-stimulated increase in PVF was blunted by lanreotide (AUC, % x min): 62,709.6 +/- 6,817 (placebo) vs. 45,237 +/- 2,507 (lanreotide), p < 0.05. Lanreotide also blunted the postprandial increase in heart rate for the first 2 h of meal perfusion. CONCLUSIONS: Because of potent inhibition of postprandial splanchnic hyperemia in patients with liver cirrhosis, lanreotide may be useful in the treatment of complications of portal hypertension.     

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.     

Comparison of prevalence for paraumbilical vein patency in patients with viral and alcoholic liver cirrhosis

OBJECTIVES: The patent paraumbilical vein (PUV) is a venous collateral that is often found in patients with cirrhosis and portal hypertension. It can be effectively demonstrated by conventional ultrasonography (US). We conducted this prospective study to elucidate the prevalence and etiology of PUV patency for cirrhotic patients. METHODS: From August, 1997, to July, 1998, one of the authors (S.-N.L.) observed PUV patency for all cirrhotic patients during routine upper abdominal US examination. All cirrhotic patients diagnosed with portal hypertension were further analyzed. Portal hypertension was diagnosed by sonographic evidence of splenomegaly or ascites, or endoscopic varices. Cases presenting with hepatocellular carcinoma and sonographic evidence of prehepatic portal hypertension were excluded. Once a PUV patency with a diameter of > or = 3 mm was suspected based on conventional US, it was confirmed by color Doppler US. Of the 493 cirrhotic patients examined, 252 with portal hypertension and without hepatoma were enrolled in this study. RESULTS: Significant PUV patency was detected in 11.1% of the enrolled patients (28 of 252). With univariate analysis, a significantly higher prevalence was demonstrated for alcoholic patients (p < 0.0001), whereas prevalence was relatively low for those with chronic hepatitis B or C infection (p = 0.0159). A trend toward increased prevalence was noted with Child-Pugh classification (p = 0.001). Furthermore, a higher prevalence was noted in younger cirrhotic patients (p = 0.0037). Alcoholism was still a significant factor despite adjustment of Child-Pugh classification using multiple logistic regression, (OR = 3.88, 95% CI = 1.34-8.55). CONCLUSION: A significantly higher prevalence of PUV patency was demonstrated for patients with alcohol-induced liver cirrhosis in comparison to those with postviral cirrhosis.     

Octreotide ameliorates the increase in collateral blood flow during postprandial hyperemia in portal hypertensive rats

BACKGROUND/AIMS: The aims of this study were to examine, in a conscious rat model of portal hypertension, the effect of postprandial splanchnic hyperemia on collateral blood flow and to determine whether octreotide has an effect on postprandial collateral flow changes. METHODS: In rats with portal vein ligation, pulsed-Doppler flowmeters were implanted chronically around the splenorenal venous shunt (SRS), which is the main spontaneous collateral vessel in the portal hypertensive rat and around the superior mesenteric artery (SMA). Changes in flow after a standard liquid meal gavage and after the administration of octreotide were examined in the rat under unanesthetized and unrestricted conditions. RESULTS: SRS flow increased significantly after gavage with a standard liquid meal (10.6+/-2.9%) compared to orogastric intubation alone (-6.5+/-2.1%) (P<0.01). Similar flow changes were observed in the SMA after liquid meal gavage. The subcutaneous administration of octreotide at a dose of 400 g/kg reduces basal SRS flow (-19.5+/-2.3%) and significantly attenuated the change in SRS flow after liquid meal gavage (-8.1+/-2.9%) compared to animals that received placebo (3.6+/-4.1% and 27.8+/-7.6%, respectively) (P<0.05). CONCLUSION: These results demonstrate that, in an experimental model of prehepatic portal hypertension, postprandial splanchnic hyperemia results in an increase in collateral flow that can be ameliorated with the use of octreotide.     

Central Nervous System Alterations in Liver Cirrhosis: The Role of Portal-Systemic Shunt and Portal Hypoperfusion

The role of portal-systemic shunting and portal liver hypoperfusion in the pathophysiology of central nervous system dysfunction of cirrhosis is not yet well defined. It is well known that one of the most important collateral vessels (CV) is a patent paraumbilical vein (PUV) but there is controversy regarding its clinical significance. We have evaluated the relationships between neuropsychological and EEG alterations, ammonia plasma level (NH₄), hepatic function, and portal hemodynamics (Doppler Ultrasound) in 95 cirrhotic patients. Patency, diameter, or flow of PUV or the presence of other CV were not related to an increased prevalence of neuropsychological or EEG abnormalities. Patients with effective portal flow (EPF = portal flow – PUV flow) lower than 692 mL/min (median) had a significantly higher risk of failing the neuropsychological test, or of having an altered EEG. Low EPF and prothrombin time (<50%), and high NH₄ (51 mol/L) were independent predictors of an abnormal EEG. Considering both low EPF and the numerosity of CV, only low EPF was found to explain EEG alterations. In conclusion, portal liver hypoperfusion and decreased liver function were associated with an increased risk of central nervous system dysfunction in cirrhotic patients, whereas PUV patency per se was not.     

Central Nervous System Alterations in Liver Cirrhosis: The Role of Portal-Systemic Shunt and Portal Hypoperfusion

The role of portal-systemic shunting and portal liver hypoperfusion in the pathophysiology of central nervous system dysfunction (CNSD) of cirrhosis is not yet well defined. It is well known that one of the most important collateral vessels (CVs) is a patent paraumbilical vein (PUV), but there is controversy regarding its clinical significance. We have evaluated the relationships between neuropsychological and EEG alterations, ammonia plasma level (NH₄), hepatic function, and portal hemodynamics (Doppler Ultrasound) in 95 cirrhotic patients. Patency, diameter, or flow of PUV or the presence of other CVs were not related to an increased prevalence of neuropsychological or EEG abnormalities. Patients with effective portal flow (EPF = portal flow – PUV flow) lower than 692 mL/min (median) had a significantly higher risk of failing the neuropsychological test, or of having an altered EEG. Low EPF and prothrombin time (<50%), and high NH₄ (51 mol/L) were independent predictors of an abnormal EEG. Considering both low EPF and the numerosity of CVs, only low EPF was found to explain EEG alterations. In conclusion, portal liver hypoperfusion and decreased liver function were associated with an increased risk of CNSD in cirrhotic patients, whereas PUV patency per se was not.     

Effect of meal on portal hemodynamics in healthy humans and in patients with chronic liver disease

The effect of a standard Italian meal on portal hemodynamics was evaluated in 12 normal subjects, in 11 patients with chronic active hepatitis and in 11 patients with liver cirrhosis using duplex Doppler ultrasound, which allows a noninvasive assessment of portal blood flow. In the fasting state, the portal vein caliber was significantly higher in patients with liver cirrhosis than in normal subjects and patients with chronic active hepatitis, whereas the mean flow velocity in the portal vein was significantly lower in this group. Basal flow volume of the portal vein was greater in patients with liver cirrhosis than in normal subjects and patients with chronic active hepatitis. Sixty minutes after the standard meal, we observed both in normal subjects and in patients with chronic active hepatitis a significant increase of mean caliber, mean velocity and flow volume in the portal vein, whereas in patients with liver cirrhosis, these parameters remained almost unchanged. In addition, the examination of individual patterns showed that flow velocity and flow volume in the portal vein decreased in some cirrhotic patients after the meal. This behavior is probably related to the hypertensive state in the splanchnic venous bed and diversion of splanchnic blood flow into spontaneous portosystemic collaterals.     

Increased splanchnic arterial vascular resistance in oldest old patients

OBJECTIVES: The aim of this study was to evaluate possible age-related changes in mesenteric artery and portal venous blood flow dynamics in relation to systemic haemodynamics in order to delineate putative haemodynamic changes relevant for postprandial hypotension in the elderly. Studies were performed over a wide age-range and for the first time in over 85-year-old patients. DESIGN: Superior mesenteric artery (SMA) parameters (diameter, peak systolic velocity, end diastolic velocity, pulsatility index, volume flow) and portal vein (PV) parameters (diameter, portal vein velocity, volume flow) were measured by duplex ultrasound (General Electrics, Vivid 3) in 98 fasting subjects aged from 21 to 96 years. Systemic vascular parameters such as blood pressure, heart rate and cardiac output (echocardiography) were also determined. Excluded were patients with severe heart failure, liver cirrhosis, sepsis and those with mesenteric artery stenosis. RESULTS: Pulsatility index (PI) was positively correlated with age (r=0.33, p=0.015). In patients over 85 years, PI was significantly increased (p=0.002) as compared to younger controls. Cardiac output was negatively correlated with age (r=-0.247, p=0.005). The other haemodynamic parameters did not show age-dependent alterations. CONCLUSION: The increase of PI in the SMA in patients over 85 years represents an increase of vascular resistance in the splanchnic area, because PI is sensitive to resistance changes of small arterial vessels. The pulsatility index in the splanchnic area seems to rise steeply in oldest old patients, probably as an attempt to compensate diminutions in cardiac output seen in this age group. These findings indicate that the splanchnic vascular bed is already used in the fasting state to guarantee systemic haemodynamics. Vasodilatation of this vascular bed as physiologically seen postprandially may therefore easily induce postprandial hypotension in the oldest old.     

Different hemodynamic patterns of alcoholic and viral endstage cirrhosis: Analysis of explanted liver weight,degree of fibrosis and splanchnic Doppler parameters

Objective. In cirrhosis, portal hemodynamics is usually considered independently of the disease etiology. The objective of this study was to investigate the role of the etiology of liver disease on the relationship between liver blood flow and liver pathology in endstage cirrhosis. Material and methods. Portal blood velocity and volume, congestion index of the portal vein, and hepatic and splenic pulsatility indices were evaluated with echo-Doppler in cirrhotic patients immediately before liver transplantation. When a patent paraumbilical vein was present, its blood flow was measured and effective portal liver perfusion was calculated as portal blood flow minus paraumbilical blood flow. The hemodynamic parameters were correlated with liver weight and the pattern of the liver fibrosis morphometrically assessed in explanted livers. A total of 131 patients with alcoholic or viral cirrhosis were included in the study. Results. In alcoholic cirrhosis, liver weight was higher than that in viral disease (1246±295 g versus 1070±254 g, p=0.001), portal liver perfusion per gram of liver tissue was lower (0.49±0.36 ml g^?1 min^?1 versus 0.85±0.56 ml g^?1 min^?1, p=0.004) and hepatic pulsatility indices were higher (1.45±0.31 versus 1.26±0.30, p=0.018). The degree of liver fibrosis was similar in alcoholic and viral cirrhosis (11.7±5.5% versus 11.0±4.4%, p=NS). An inverse relationship between liver weight and Child-Pugh score was disclosed in viral (p<0.001) but not in alcoholic disease. Conclusions. A different hemodynamic pattern characterizes the advanced stage of cirrhosis of alcoholic and viral origin. A more severe alteration of intrahepatic portal perfusion, probably coexisting with a more severe hepatocyte dysfunction, and a higher liver weight can be detected in alcoholic cirrhosis.     

Octreotide blunts postprandial splanchnic hyperemia in cirrhotic patients: A double-blind randomized echo-doppler study

The effect of octreotide, a long-acting synthetic analog of somatostatin, on fasting and postprandial splanchnic hemodynamics was investigated in cirrhotic patients. Splanchnic hemodynamics were assessed using an echo-Doppler duplex system in a prospective, double-blind, placebo-controlled, crossover study performed on 2 separate days, 1 week apart, in 30 cirrhotic patients. Measurements of portal vein (PV) cross-sectional area (PVA) and mean velocity (PV-V), and of superior mesenteric artery (SMA) mean velocity (SMA-V) and pulsatility index (SMA-PI) (an index of vascular resistance) were performed at baseline, 30 minutes after octreotide (200 μg subcutaneously) or placebo administration, and 30 and 60 minutes after the ingestion of a liquid meal. In the fasted state, octreotide induced a significant decrease in PV-V (−7%) and in SMA-V (−10%) and an increase in PI (+16%). On the day of placebo administration, meal ingestion induced a significant increase in PV-V (+21%) and in SMA-V (+43%) and a decrease in PI (−21%). In contrast, meal ingestion on octreotide day induced significantly smaller increases in PV-V (+10%) and in SMAV (+18%) and a significantly smaller decrease in PI (−10%). Octreotide, although producing a mild reduction in PV-V and SMA-V in the fasted state, markedly blunts postprandial splanchnic hyperemia in cirrhotic patients.     

Mesenteric blood flow is related to disease activity and risk of relapse in Crohn''s disease: a prospective follow-up study

OBJECTIVE: The diagnostic significance of increased splanchnic blood flow in Crohn's disease is unclear. This prospective study was therefore undertaken to define the role of Doppler sonography in the assessment of disease activity and in the prediction of early relapse. METHODS: Splanchnic flowmetry was performed in 59 patients with Crohn's disease and 20 healthy volunteers during fasting and 30 min after ingestion of a standardized meal. Twenty-one patients measured during the active state and in clinical remission were followed-up for 6 months. Hemodynamic parameters of the superior and inferior mesenteric arteries and the portal vein were related to clinical (Crohn's disease activity index [CDAI]), laboratory (C-reactive protein), and endoscopic (Crohn's Disease Endoscopic Index of Severity) parameters of disease activity. RESULTS: The postprandial mean velocity of the superior mesenteric artery correlated closest with clinical activity (CDAI, p < 0.005) and C-reactive protein (p < 0.01), but was unrelated to endoscopic activity. All patients in remission after 6 months (9/9) showed an increase in postprandial pulsatility index of the superior mesenteric artery, compared with an initial measurement during active disease (+28%). In contrast, the majority of patients with later relapse or surgery (11/12) had decreased pulsatility index during initial remission (-20%). The positive predictive value of this index for maintenance of remission was 0.82. CONCLUSIONS: Postprandial flow measurements in the superior mesenteric artery are closely related to clinical but not endoscopic disease activity in patients with Crohn's disease. The repeated measurement of the postprandial pulsatility index allows estimation of the risk of recurrence.     

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

OBJECTIVE: The aim of the study was to assess postprandial splanchnic hemodynamic changes in cirrhosis in relation to variceal status. METHODS: In 9 healthy controls and 56 patients with liver cirrhosis, stratified according to variceal status and presence of spontaneous portal-systemic shunts, the portal vein diameter and flow velocity, the congestion index of the portal vein, and the resistive index of the superior mesenteric artery (SMA-RI) were studied by Doppler ultrasound before and 30, 60, and 120 min after the intake of a standard meal. Comparison of postprandial parameters with basal ones was done within each group by paired t test and among groups by ANOVA and Duncan test. RESULTS: Healthy controls and cirrhotic patients without varices showed similar significant splanchnic hemodynamic changes, namely a reduction of SMA-RI (-13% at 30 min) and a consequent increase in portal vein diameter (respectively, +32% and +17% in the two groups) and velocity (+66% and +51%). A significant reduction of SMA-RI was also found in patients with varices, irrespective of the variceal size (range, -7 to -11%), but the expected portal vein dilation and velocity increase were progressively blunted with the increase of variceal size (range, 0-5% for diameter and 5-19% for velocity). Patients with spontaneous portal-systemic shunts showed a response similar to that of patients with large varices. Significant modification of the congestion index of the portal vein did not occur in any group. CONCLUSIONS: Our results show that the hemodynamic response to meal in patients with liver cirrhosis is influenced by the presence and size of esophageal varices and the presence of spontaneous portal-systemic shunts.     

Upright posture blunts postprandial splanchnic hyperemia in patients with cirrhosis and portal hypertension

The aim of this study was to compare postprandial hemodynamic changes observed during assumption of the recumbent posture and upright posture in patients with cirrhosis and portal hypertension. Eleven patients with cirrhosis and portal hypertension were studied. Echo-Doppler examinations were performed to measure flow volume in the portal vein (PV), superior mesenteric artery (SMA), and splenic artery (SA) in the fasting condition. Collateral blood flow was indirectly calculated by determining the difference between the sum of SMA, SA, and PV blood flows. After these measurements were done, each patient received a standardized liquid meal and was then randomly assigned to either maintain supine or upright posture, in a crossover design, on 2 different days (recumbent day and upright day). On each study day, the above-mentioned measurements were repeated 30 min and 60 min after the meal. PV blood flow increased significantly after the meal on the recumbent day (P < 0.01) but not on the upright day (P = 0.78). Although there were significant postprandial increases in SMA blood flow on both study days (P < 0.01, P < 0.01), the effect was less pronounced on the upright day than on the recumbent day (P < 0.01). Postprandial SA blood flow showed no change on the recumbent day (P = 0.64), but decreased significantly on the upright day (P < 0.01). The calculated postprandial collateral blood flow increased significantly on the recumbent day (P < 0.05), but showed no change on the upright day (P = 0.53). These results suggest that the upright posture blunts postprandial splanchnic hyperemia in patients with cirrhosis and portal hypertension. Received: April 13, 1998/Accepted: September 25, 1998     

Portal Hemodynamic Responses after Oral Intake of Glucose in Patients with Cirrhosis

Changes of portal, superior mesenteric, and splenic venous flows, and portohepatic gradient (portal vein pressure minus free hepatic vein pressure) after a meal were studied in patients with cirrhosis using the duplex ultrasonic Doppler flowmeter, and portal and hepatic vein catheterizations after ingestion of 227 ml of 33% glucose solution (300 kcal). As a control, changes of portal venous flow and portohepatic gradient after drinking 227 ml of water, were studied. Portal and superior mesenteric venous flows increased significantly at 30 min after glucose intake, and they returned gradually to the basal values, whereas no significant postprandial change occurred in splenic venous flow. The sum of superior mesenteric and splenic venous flows was greater than the estimated portal venous flow before glucose intake, and the difference widened during post-prandial mesenteric hyperemia, indicating an increase of blood flow into the portal-systemic shunts. After glucose intake, portohepatic gradient elevated immediately, in parallel with an increase of portal venous flow, and these changes persisted for the 30 min studied; however, no significant change occurred in these parameters after drinking water. In conclusion: 1) In patients with cirrhosis, hyperemia occurs in the intestine but not in the spleen after glucose intake, and 2) postprandial mesenteric hyperemia causes an increase of portal venous inflow, portal-systemic collateral flow, portal venous flow, and an elevation of portohepatic gradient.     

Modulation of splanchnic circulation:Role in perioperative management of liver transplant patients

Splanchnic circulation is the primary mechanism thatregulates volumes of circulating blood and systemic blood pressure in patients with cirrhosis accompanied by portal hypertension. Recently, interest has been expressed in modulating splanchnic circulation in patients with liver cirrhosis, because this capability might produce beneficial effects in cirrhotic patients undergoing a liver transplant. Pharmacologic modulation of splanchnic circulation by use of vasoconstrictors might minimize venous congestion, replenish central blood flow, and thus optimize management of blood volume during a liver transplant operation. Moreover, splanchnic modulation minimizes any high portal blood flow that may occur following liver resection and the subsequent liver transplant. This effect is significant, because high portal flow impairs liver regeneration, and thus adversely affects the postoperative recovery of a transplant patient. An increase in portal blood flow can be minimized by either surgical methods(e.g., splenic artery ligation, splenectomy or portocaval shunting) or administration of splanchnic vasoconstrictor drugs such as Vasopressin or terlipressin. Finally, modulation of splanchnic circulation can help maintain perioperative renal function. Splanchnic vasoconstrictors such as terlipressin may help protect against acute kidney injury in patients undergoing liver transplantation by reducing portal pressure and the severity of a hyperdynamic state. These effects are especially important in patients who receive a too small for size graft. Terlipressin selectively stimulates V1 receptors, and thus causes arteriolar vasoconstriction in the splanchnic region, with a consequent shift of blood from splanchnic to systemic circulation. As a result, terlipressin enhances renal perfusion by increasing both effective blood volume and mean arterial pressure.