Changes In Splanchnic Circulation Research Articles

Effect of meal intake for evaluating hepatic artery by Doppler ultrasonography in liver transplants: Does fasting matter for screening hepatic artery due to hemodynamic changes in splanchnic circulation?

The aim of this study is to assess the utility of fasting on Doppler ultrasonography findings of hepatic artery in liver transplants. Liver transplant patients without vascular abnormalities were prospectively evaluated between December 2017 and January 2020. Doppler sonography was used to describe hemodynamic changes in response to a standard meal. The diameter, peak systolic velocity, blood flow, resistive index (RI) of the main hepatic artery and portal vein peak velocity were measured. The mean hepatic arterial diameter of 44 patients was higher in the fasting group (4.5mm) than in the postprandial group (3.3mm) (p<.05). The mean hepatic arterial blood flow decreased (from .276 to .127 L/min) and hepatic arterial RI increased (from .66 to .71) following meal ingestion (p<.05). Hepatic arterial velocity was significantly lower and portal venous velocity was higher after oral intake. Meal ingestion has an important effect on hepatic artery Doppler features in liver transplants. Therefore, Doppler ultrasound evaluation should be considered after appropriate fasting due to postprandial responses of liver transplant.

Complication of Cirrhosis Portal Hypertension: A Review

Portal hypertension is responsible for most of the complications that mark the transition from compensated to decompensated cirrhosis, namely variceal hemorrhage, ascites and hepatic encephalopathy. Gastroesophageal varices result almost solely from portal hypertension, although the hyperdynamic circulation contributes to variceal growth and rupture. Ascites results from sinusoidal hypertension (portal hypertension) and sodium retention, which is, in turn, secondary to vasodilatation and activation of neurohumoral systems. The hepatorenal syndrome results from extreme vasodilatation with extreme decrease in effective blood volume and maximal activation of vaso constrictive systems, renal vasoconstriction and renal failure, which is probably an indirect effect of the changes in splanchnic circulation. Spontaneous bacterial peritonitis, a frequent precipitant of the hepatorenal syndrome, most probably results from deficient immunity, resulting in pathological gut bacterial translocation. Hepatic encephalopathy results from portosystemic shunting and hepatic insufficiency leading to accumulation of neurotoxins, mainly ammonia, in the brain. As for any illness, prediction of death in cirrhosis is essential in its management; and the development of portal hypertension and its complications have important prognostic value.

Very early postnatal changes in splanchnic circulation in term infants

Reversed blood flow has been reported in the superior mesenteric artery (SMA) in 92% of healthy term newborns at 2h of age. By 24h after birth the end-diastolic velocity became positive in all of the infants. To characterize hemodynamic changes in the coeliac artery and superior mesenteric artery in healthy term newborns during the first 6h after birth and to specify the time interval when the negative values of end-diastolic velocity in the superior mesenteric artery become positive. Our study included 30 healthy term newborns. The blood flow velocity was assessed by Doppler ultrasonography at 2h, 4h and 6h after birth. The end-diastolic velocity in the superior mesenteric artery changed from negative values at the age of 2h (-0.9cm/s, range -13.2 to 0.0) to positive (7.08cm/s, range 6.3 to 13.5, P < 0.001) at 6h after birth. In the coeliac artery, the end-diastolic velocity increased during this period, but negative values were not observed (11.8cm/s, range 9.3 to 13.9 at 2h and 18.03cm/s, range 14.2 to 27.6 at 6h). Important changes occur in splanchnic circulation during the first 6h after birth. The rise in end-diastolic velocity in the superior mesenteric artery from negative to positive values in 83% of healthy term newborns is the most important change.

106 Early Postnatal Changes in Splanchnic Circulation in Healthy Term Newborns

ObjectiveTo characterize hemodynamic changes in celiac artery (CA) and superior mesenteric artery (SMA) in healthy term newborns during the first six hours after birth by means of Doppler ultrasonography.Materials and...

Dilated SMV in Colon Cancer—Is There any Significance

Changes in splanchnic circulation have been seen in patients with colorectal cancer. We have previously reported that the inferior mesenteric vein is dilated in rectal cancer. We wanted to assess whether the superior mesenteric vein (SMV) is dilated in right-sided colon cancer. From a colorectal database, three cohorts were formed: right colon cancer, rectal cancer, and normal. The SMV (2 cm proximal to the confluence of the SMV and portal vein) and the gastrocolic trunk (GCT) were saved and anonymized. The short-axis diameter of the vein was measured independently by three radiologists. The diameter of the SMV and GCT was higher in the right colon group than the other two groups. There was no correlation with the stage of tumor (locoregional or metastatic). Patients with right colon cancer showed a significantly increased mean SMV diameter at presentation, which may be due to increased venous return secondary to neovascularization. Further studies are required to evaluate this further.

Hemodynamic changes in visceral organs following closed head trauma in rats

Gastrointestinal (GI) tract dysfunction is well documented following head injury. Our study sought to determine whether head injury causes an immediate impairment of the splanchnic circulation which may contribute to later GI sequelae. Three groups of eight rats each received either no closed head trauma (CHT) (group 1) or CHT (groups 2 and 3) immediately following baseline measurements at time 0. The primary measures of interest - individual organ blood flows and cardiac output (radioactive microspheres), and individual organ and systemic vascular resistances - were determined in the control group, at 5 min after CHT in group 2, and at 15 min after CHT in group 3. CHT caused no significant change in portal venous inflow (flows were 2.40+/-0.36, 2.38+/-0.54, and 2.33+/-0.62 ml min(-1) 100g(-1)bw, mean+/-S.D., in groups 1, 2, and 3, respectively). Individual organ and total hepatic blood flow, cardiac index, splanchnic, portal, and total peripheral resistance, and mean arterial or portal venous pressure also did not differ significantly among groups. We found no significant changes in splanchnic circulation immediately after CHT in this rat model. Our results do not support the hypothesis that the splanchnic circulation is impaired immediately after head injury and that splanchnic blood flow impairment immediately after head injury may contribute to post-head injury GI dysfunction.

Changes in splanchnic circulation during an alveolar recruitment maneuver in healthy porcine lungs.

Recruitment maneuvers (RM) are advocated as a complement to mechanical ventilation during anesthesia and in acute lung injury. However, they produce high intrathoracic pressures and volumes that may compromise hemodynamics. Our aim was to analyze the effect of a RM on hemodynamics in 10 anesthetized pigs. We assessed carotid, pulmonary, femoral, and hepatic arterial pressures, hepatic and portal venous pressures, total splanchnic (celiac trunk + superior mesenteric artery), hepatic, splenic, renal, and carotid arterial flows, and portal venous flow. We recorded hemodynamics, respiratory mechanics and blood gases before and at 8 min after RM (sustained inflation to 40 cm H(2)O of airway pressure lasting 20 s). Hemodynamics were also measured during RM, and at 1, 3, and 5 min after RM. All flows (P = 0.030) and arterial pressures (P < or = 0.048) decreased during RM, whereas venous pressures increased (P = 0.030). Flows and pressures returned to 75%-109% of baseline immediately after RM. Total splanchnic, renal and portal flows remained decreased at 8 min after RM (P < or = 0.042). Oxygenation did not change, and respiratory mechanics improved after the RM. RM produced a marked, though transitory, impairment of blood flow in all studied vessels. Despite prompt partial recovery, total splanchnic circulation remained reduced at 8 min after RM. This residual decrease may present a risk in conditions with markedly compromised circulatory reserves. Recruitment maneuvers (RM) produce high intrathoracic pressures and volumes that may compromise hemodynamics. We found a marked transient impairment of hemodynamics during a RM in 10 anesthetized pigs. At 8 min after RM, blood flow remained reduced in the celiac trunk, superior mesenteric, and renal arteries, as well as in the portal vein. This residual decrease may present a risk in conditions with markedly compromised circulatory reserves.

Hemodynamic changes in splanchnic circulation after orthotopic liver transplantation in patients with liver cirrhosis.

Liver cirrhosis increases portal vein pressure and alters the splanchnic circulation. With Doppler sonography, we investigated the hemodynamic changes in the portal vein, superior mesenteric artery, hepatic and splenic arteries and spleen size in a group of patients with end-stage liver disease before and after orthotopic liver transplantation (OLT). Ten patients (seven male, three female; mean age = 48.8 +/- 7.6 years) who underwent OLT for liver cirrhosis mainly associated with hepatitis C virus infection completed the study. The control group consisted of 10 patients matched by sex and age who had no gastroenterologic or vascular diseases. All patients underwent duplex Doppler sonography (Toshiba SSA 270A with a 3.5-MHz probe) after 24 h of fasting (baseline) and then 6 and 12 months after OLT. The following parameters, expressed as the mean of three measurements, were evaluated: portal flow velocity (PFV), pulsatility index of the superior mesenteric artery (MAPI), resistance indexes of the hepatic (HARI) and splenic (SARI) arteries, and longitudinal diameter of the spleen (LDS). PFV in the pre-OLT phase was significantly lower in the patients than in the controls ( p < 0.0001); it progressively and significantly increased over baseline levels at 6 and 12 months ( p < 0.0001), approaching control values. LDS in the pre-OLT phase was significantly higher than in controls ( p < 0.0001); after OLT, it decreased significantly compared with baseline values ( p < 0.005). The MAPI of patients in the pre-OLT phase was lower than that in controls ( p < 0.0001); post-OLT, it progressively increased and reached values that were significantly above baseline at 12 months ( p < 0.005). In the pre-OLT phase, the HARI and SARI were significantly higher than in controls ( p < 0.04); 6 and 12 months after OLT, those values were significantly below baseline values ( p < 0.001), and there was no significant difference from control values. These data show that many of the hemodynamic parameters typical of decompensated cirrhosis improve progressively within 12 months after transplantation.

Effects of the biguanide metformin on splanchnic blood flow in rats: preferential and dose-dependent increase in islet blood flow.

The aim of the present study was to evaluate if metformin, a biguanide used in the treatment of noninsulin-dependent diabetes, induced any changes in splanchnic circulation. For this purpose, anesthetized rats were injected intraperitoneally with saline alone (1 ml/kg BW) or metformin (15 or 30 mg/kg BW) 30 min before blood flow measurements. No effects on blood glucose or serum insulin concentrations could be discerned after administration of metformin. Both duodenal, whole pancreatic and islet blood flow were approximately doubled by the lowest dose (15 mg/kg BW) metformin. However, the higher dose (30 mg/kg BW) did not affect duodenal or pancreatic blood flow, whereas islet blood flow was markedly increased also in this group of animals. It is concluded that the blood flow to the pancreatic islets can be specifically enhanced by metformin. To what extent this contributes to the antihyperglycemic action of the drug is presently unknown.

Modulation of the hyperdynamic circulation of cirrhotic rats by nitric oxide inhibition

The effects of NG-monomethyl-l-arginine (l-NMMA), an inhibitor of nitric oxide (NO) biosynthesis on the splanchnic and systemic circulation, were investigated in rats with cirrhosis induced by carbon tetrachloride. Portal hypertension in these rats was accompanied by decreased arterial blood pressure and peripheral vascular resistance as well as by splanchnic vasodilation with increased portal venous inflow and decreased splanchnic resistance. Intravenous bolus administration of l-NMMA (25 mg/kg) significantly increased systemic blood pressure and decreased cardiac output. l-NMMA also significantly increased systemic and splanchnic vascular resistance; whereas blood flow to the stomach, small intestine, colon, pancreas, mesentery, spleen, and kidney was decreased significantly. l-NMMA did not alter the portal pressure or porto-systemic shunting in these cirrhotic rats, yet portal vascular resistance increased, suggesting effects on the intrahepatic and collateral circulation. Pretreatment with l-arginine (300 mg/kg) prevented the hemodynamic changes induced by l-NMMA. These findings support the concept that local excess formation of NO contributes to changes in splanchnic circulation associated with portal hypertension in cirrhosis.

Tryglycylvasopressin-reduced portal and systemic concentrations of serum bile acids after exogenous chenodeoxycholic acid load in rats as a reflection of reduced splanchnic blood flow.

The effect of triglycylvasopressin (TGVP) on the absorption of chenodeoxycholic acid (CDCA) was investigated in three groups of six rats (controls, CDCA, CDCA + TGVP) through the evaluation of portal and caval serum bile acids (SBA) concentrations after an oral load with CDCA to investigate whether changes in this parameter reflect variations in splanchnic blood flow induced by a vasoconstrictor. The results indicate that CDCA was absorbed and led to a significant increase in SBA. This increase was reduced by TGVP administration: portal blood 380.0 +/- 61.2 vs 279.7 +/- 45.3; caval blood 151.8 +/- 45.7 vs 41.7 +/- 12.5 (mumol/l; mean +/- s.d.). This suggests that variations in SBA concentrations could reflect changes in splanchnic circulation.

Splenic artery and superior mesenteric artery blood flow: nonsurgical Doppler US measurement in healthy subjects and patients with chronic liver disease.

The accuracy of the duplex Doppler ultrasound system in the measurement of blood flow in the splenic artery and the superior mesenteric artery was evaluated in seven anesthetized dogs by comparing blood flow recordings obtained simultaneously with the electromagnetic flowmeter, with those obtained with the combination of B-mode and M-mode scanning. Various flow rates were produced by the infusion of dopamine. Splenic artery blood flow and superior mesenteric artery blood flow measured with the duplex system exhibited significant correlations with corresponding values obtained with electromagnetic flow measurements (r = .93 and r = .93, respectively). Changes in splanchnic circulation with the progression of chronic liver disease in humans were then investigated with the use of the duplex system. Splenic artery blood flow and superior mesenteric artery blood flow were significantly increased in patients with cirrhosis compared with patients with chronic hepatitis and healthy subjects. These results indicate that a hyperdynamic circulatory state may develop in the splanchnic circulation of the intestine and spleen in cirrhotic patients.