Decrease In Portal Venous Pressure Research Articles

Development of a new Cox model for predicting long-term survival in hepatitis cirrhosis patients underwent transjugular intrahepatic portosystemic shunts.

Transjugular intrahepatic portosystemic shunt (TIPS) placement is a procedure that can effectively treat complications of portal hypertension, such as variceal bleeding and refractory ascites. However, there have been no specific studies on predicting long-term survival after TIPS placement. To establish a model to predict long-term survival in patients with hepatitis cirrhosis after TIPS. A retrospective analysis was conducted on a cohort of 224 patients who underwent TIPS implantation. Through univariate and multivariate Cox regression analyses, various factors were examined for their ability to predict survival at 6 years after TIPS. Consequently, a composite score was formulated, encompassing the indication, shunt reasonability, portal venous pressure gradient (PPG) after TIPS, percentage decrease in portal venous pressure (PVP), indocyanine green retention rate at 15 min (ICGR15) and total bilirubin (Tbil) level. Furthermore, the performance of the newly developed Cox (NDC) model was evaluated in an internal validation cohort and compared with that of a series of existing models. The indication (variceal bleeding or ascites), shunt reasonability (reasonable or unreasonable), ICGR15, postoperative PPG, percentage of PVP decrease and Tbil were found to be independent factors affecting long-term survival after TIPS placement. The NDC model incorporated these parameters and successfully identified patients at high risk, exhibiting a notably elevated mortality rate following the TIPS procedure, as observed in both the training and validation cohorts. Additionally, in terms of predicting the long-term survival rate, the performance of the NDC model was significantly better than that of the other four models [Child-Pugh, model for end-stage liver disease (MELD), MELD-sodium and the Freiburg index of post-TIPS survival]. The NDC model can accurately predict long-term survival after the TIPS procedure in patients with hepatitis cirrhosis, help identify high-risk patients and guide follow-up management after TIPS implantation.

Effects of Phlebotomy and Phenylephrine Infusion on Portal Venous Pressure and Systemic Hemodynamics During Liver Transplantation

A regimen of fluid restriction, phlebotomy, vasopressors, and strict, protocol-guided product replacement has been associated with low blood product use during orthotopic liver transplantation. However, the physiologic basis of this strategy remains unclear. We hypothesized that a reduction of intravascular volume by phlebotomy would cause a decrease in portal venous pressure (PVP), which would be sustained during subsequent phenylephrine infusion, possibly explaining reduced bleeding. Because phenylephrine may increase central venous pressure (CVP), we questioned the validity of CVP as a correlate of cardiac filling in this context and compared it with other pulmonary artery catheter and transesophageal echocardiography-derived parameters. In particular, because optimal views for echocardiographic estimation of preload and stroke volume are not always applicable during liver transplantation, we evaluated the use of transmitral flow (TMF) early peak (E) velocity as a surrogate. In study 1, the changes in directly measured PVP and CVP were recorded before and after phlebotomy and phenylephrine infusion in 10 patients near the end of the dissection phase of liver transplantation. In study 2, transesophageal echocardiography-derived TMF velocity in early diastole was measured in 20 patients, and the changes were compared with changes in CVP, pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and calculated systemic vascular resistance (SVR) at the following times: postinduction, postphlebotomy, preclamping of the inferior vena cava, during clamping, and postunclamping. Phlebotomy decreased PVP along with CO, PAP, PCWP, CVP, and TMF E velocity. Phenylephrine given after phlebotomy increased CVP, SVR, and arterial blood pressure but had no significant effect on CO, PAP, PCWP, or PVP. The change in TMF E velocity correlated well with the change in CO (Pearson correlation coefficient 95% confidence interval 0.738-0.917, P< or =0.015) but less well with the change in PAP (0.554-0.762, P< or =0.012) and PCWP (0.576-0.692, P< or =0.008). TMF E velocity did not correlate significantly with CVP or calculated SVR. Phlebotomy during the dissection phase of liver transplantation decreased PVP, which was unaffected when phenylephrine infusion was used to restore systemic arterial pressure. This may contribute to a decrease in operative blood loss. CVP often increased in response to phenylephrine infusion and did not seem to reflect cardiac filling. The changes in TMF E velocity correlated well with the changes in CO, PAP, and PCWP during liver transplantation but not with the changes in CVP.

Effect of chronic CB1 cannabinoid receptor antagonism on livers of rats with biliary cirrhosis

Recent studies have shown that the activated endocannabinoid system participates in the increase in IHR (intrahepatic resistance) in cirrhosis. The increased hepatic production of vasoconstrictive eicosanoids is involved in the effect of endocannabinoids on the hepatic microcirculation in cirrhosis; however, the mechanisms of these effects are still unknown. The aim of the present study was to investigate the effects of chronic CB(1) (cannabinoid 1) receptor blockade in the hepatic microcirculation of CBL (common bile-duct-ligated) cirrhotic rats. After 1 week of treatment with AM251, a specific CB(1) receptor antagonist, IHR, SMA (superior mesenteric artery) blood flow and hepatic production of eicosanoids [TXB(2) (thromboxane B(2)), 6-keto PGF(1alpha) (prostaglandin F(1alpha)) and Cys-LTs (cysteinyl leukotrienes)] were measured. Additionally, the protein levels of hepatic COX (cyclo-oxygenase) isoforms, 5-LOX (5-lipoxygenase), CB(1) receptor, TGF-beta(1) (transforming growth factor beta(1)), cPLA(2) [cytosolic PLA(2) (phospholipase A(2))], sPLA(2) (secreted PLA(2)) and collagen deposition were also measured. In AM251-treated cirrhotic rats, a decrease in portal venous pressure was associated with the decrease in IHR and SMA blood flow. Additionally, the protein levels of hepatic CB(1) receptor, TGF-beta(1), cPLA(2) and hepatic collagen deposition, and the hepatic levels of 5-LOX and COX-2 and the corresponding production of TXB(2) and Cys-LTs in perfusates, were significantly decreased after 1 week of AM251 treatment in cirrhotic rats. Furthermore, acute infusion of AM251 resulted in a decrease in SMA blood flow and an increase in SMA resistance in CBL rats. In conclusion, the chronic effects of AM251 treatment on the intrahepatic microcirculation were, at least partly, mediated by the inhibition of hepatic TGF-beta(1) activity, which was associated with decreased hepatic collagen deposition and the activated PLA(2)/eicosanoid cascade in cirrhotic livers.

EFFECT OF ISOSORBIDE DINITRATE ON GASTRIC BLOOD FLOW IN RATS WITH LIVER CIRRHOSIS DETERMINED BY ANALYZING GASTRIC BLOOD FLOW, PORTAL VEIN PRESSURE AND BLOOD GAS

We investigated the effects of isosorbide dinitrate (IDN) on gastric blood flow (GBF), portal venous pressure (PVP) and blood gas of rats with liver cirrhosis (LC) accompanied by portal hypertension. Thirty male Wistar rats (LC in 17 and normal in 13) were used. Before and after IDN administration, GBF, PVP and blood gas in the femoral artery and portal vein were measured. Portal blood oxygen concentration was estimated by calculating the ratio of PO2 in portal blood and that in arterial blood (PpvO2/PaO2) of each rat. The GBF in the LC rats was significantly lower than that in the normal rats. In the LC group, IDN administration significantly increased the GBF. The PpvO2/PaO2 value in the group with LC was significantly lower after IDN administration than that before IDN administration. In the investigation whether changes in PVP or Ppv/PaO2 contributed more to the change in GBF after IDN administration, a significant correlation was found between rates of change in GBF and PpvO2/PaO2 were significantly correlated (r= -0.733, p <0.05). The effect of IDN on changes in the stomach accompanying portal hypertension is mainly attributable to a decrease in preload, which suppresses inflow to the stomach, as reflected by a decrease in PpvO2/ PaO2, rather than to a decrease in afterload on GBF, as reflected by a decrease in PVP.

Understanding the splenic contribution to portal flow: The role of splenic artery ligation as inflow modification in living donor liver transplantation

Understanding the splenic contribution to portal flow: The role of splenic artery ligation as inflow modification in living donor liver transplantation

"Endemic" idiopathic portal hypertension: report on 32 patients with non-cirrhotic portal fibrosis.

The clinical features, surgical management, and long term follow up of 32 patients from Iran with idiopathic portal hypertension are reported. Many features of the disease are similar to those reported from India and Japan. The unsuspected finding was a 46% history of marked pica of clay (geophagia) in a subset of 26 patients. In addition, 81% of our patients had a prolonged prothrombin time, despite otherwise normal to minimally abnormal liver function tests. Liver biopsies revealed intrahepatic periportal fibrosis with subintimal thickening of terminal branches, and in many specimens a striking peri-ductular fibrosis was seen in the adjacent bile ducts. The spleen was very large with a dilated artery (external diameter: 11 mm to 15 mm). Portal venous pressure (PVP) was measured intra-operatively before and after clamping the splenic artery (SA). Clamping the SA consistently caused a decreased in PVP which ranged from 2.0 to 18.2 cm water with the mean +/- SEM of 9.7 +/- 1.5 cm water (p < 0.001, paired t-test). It was equivalent to 32.3 +/- 3.6% decrease in PVP. Fifteen selected patients (Group I) were managed with splenectomy with excellent short and long term results. The selection criteria for splenectomy included a decrease in PVP to < 24 cm of water after clamping the SA. Three patients from this group were re-examined 10 to 12 years following splenectomy. Cirrhosis had not developed, but the minimal abnormalities in the liver function tests had persisted.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of vasopressin on systemic capacity

To assess the effect of vasopressin (VP) on systemic capacity (SC), blood was drained from the venae cavae to an oxygenator and returned to the aorta at a constant rate so that changes in SC could be measured as the inverse of changes in oxygenator volume in 17 anesthetized pigs. After 10 min of VP administration (1.1 U/min ia), mean arterial pressure increased from 67 +/- 2 to 144 +/- 7 mmHg (P less than 0.001). SC decreased promptly and reached a nadir of 110 +/- 32 ml (P less than 0.02, 5.5 ml/kg) below control at 5 min but returned to 35 +/- 65 ml (P = not significant, 1.8 ml/kg) below control at 10 min. Portal venous pressure decreased from 19.3 +/- 2.6 to 16.6 +/- 2.7 mmHg (P less than 0.001), and portal flow decreased from 828 +/- 68 to 458 +/- 92 ml/min (P less than 0.001). Transhepatic venous resistance increased. After evisceration, VP caused only an increase in SC. Thus VP causes an initial SC decrement due entirely to a decrease in splanchnic capacity. The decrease in splanchnic capacity must be caused, at least in part, by the decrease in gastrointestinal arterial inflow and subsequent decrease in portal venous pressure. These initial effects of VP on SC would be expected to enhance ventricular filling and cardiac output in the intact animal and could be important in the acute compensatory response to hemorrhage.

Systemic and splanchnic hemodynamic effects of molsidomine in rats with carbon tetrachloride–induced cirrhosis

Molsidomine, a long-acting vasodilator mainly used as an antianginal agent, was reported to decrease the portohepatic venous pressure gradient in patients with alcoholic cirrhosis. This study investigated the effects of linsidomine, the active metabolite of molsidomine, on systemic and splanchnic hemodynamics in rats with CCl4-induced cirrhosis using the microsphere technique. Compared with placebo-treated rats, linsidomine-treated animals were found to have a significant decrease in portal venous pressure (-18%, p less than 0.01) and in mean arterial pressure (-16%, p less than 0.01), smaller peripheral resistances (p less than 0.01), greater portal venous inflow (p less than 0.05), smaller splanchnic arteriolar resistances (p less than 0.01) and smaller protocol-lateral resistances (p less than 0.05). Cardiac output, hepatic arterial blood flow, portal blood flow and estimated hepatic blood flow were not significantly different between the two groups of animals. Linsidomine-treated rats exhibited a trend toward greater collateral blood flow compared with controls, but this difference was not significant. We conclude that linsidomine decreases portal venous pressure by reducing portocollateral resistances without affecting liver blood flow. These effects should be beneficial for patients with cirrhosis and portal hypertension.

Participation of adrenoceptors in liver blood flow regulation in anesthetized dogs.

We evaluated involvement of adrenergic receptors in the responses of the hepatic vasculature to reduction either of portal venous flow or hepatic arterial inflow. Portal vein occlusion caused an increase in hepatic arterial blood flow (HAF) and decreases in hepatic arterial pressure (HAP) and hepatic arterial vascular resistance (HAR) in the intact group. After pretreatment with either yohimbine or prazosin, but not propranolol, occlusion of the portal vein produced a greater decrease in HAP as compared with that in the intact group. No significant changes in HAF, HAR, or hepatic tissue blood flow (HTF) occurred after the treatment. These results indicate that the compensatory response of the hepatic arterial vasculature to altered portal blood flow (PVF) is regulated independently of the intrahepatic adrenergic receptors. Hepatic arterial occlusion caused a significant decrease in portal venous pressure, PVF, and HTF. Portal venous vascular resistance (PVR) was reduced slightly, but not significantly. After pretreatment with either yohimbine or prazosin, but not propranolol, occlusion of the hepatic artery produced an opposite effect: to increase PVF and significantly decrease PVR. These results indicate that intrahepatic alpha-adrenoceptors participate in the regulation of portal vascular tone to maintain portal vein pressure at a steady level, when inflow from the hepatic artery is reduced.

Effect of propranolol on hepatic blood flow in normal and portal hypertensive rats.

1. The effects of propranolol on heart rate, arterial pressure, portal venous pressure and fractional hepatic blood flow were studied in rats with hepatic artery ligature or with portal vein stenosis, and in sham-operated rats. The effect of propranolol on cardiac output was also studied in normal rats. 2. In rats with hepatic artery ligature or with portal vein stenosis, and in sham-operated rats, propranolol decreased heart rate and portal venous pressure significantly and did not alter arterial pressure. Propranolol decreased fractional hepatic blood flow significantly in rats with hepatic artery ligature, but did not change hepatic blood flow in rats with portal vein stenosis or in sham-operated rats. 3. We conclude therefore that: (a) propranolol decreases portal venous pressure in rats; (b) this decrease in portal venous pressure results in a reduction in portal blood flow which is related, in part, to a reduction in cardiac output; (c) propranolol does not alter hepatic blood flow in normal rats or in rats with portal hypertension.

PROPRANOLOL—A MEDICAL TREATMENT FOR PORTAL HYPERTENSION?

Continuous, oral administration of propranolol at doses which reduced the heart-rate by 25% produced a sustained decrease in portal venous pressure in cirrhotic patients with portal hypertension. This effect of propranolol might be useful in preventing recurrent bleeding due to ruptured œsophageal varices in patients with portal hypertension.

Portal pressure reduction induced by partial mechanical obstruction of the superior mesenteric artery in the anesthetized dog

In an effort to avoid the potentially dangerous side effects of vasopressin infusions, we attempted to reproduce mechanically the splanchnic hemodynamic changes induced by vasopressin without its systemic effects. Superior mesenteric arterial pressure was reduced to 50 to 70 mm Hg for 30 to 60 min in 10 normal dogs by partial balloon obstruction of the superior mesenteric artery. Balloon inflation caused a decrease in portal venous pressure (5.6 ± 0.6 versus 2.8 ± 0.7 mm Hg), hepatic vein wedge pressure (4.8 ± 0.4 versus 2.3 ± 0.5 mm Hg), and portal vein flow (424 ± 53 versus 275 ± 52 ml per min), and an increase in hepatic arterial blood flow (172 ± 19 versus 217 ± 29 ml per min). Total hepatic blood flow and oxygen delivery to the liver were unchanged. Partial balloon obstruction caused an increase in cardiac output (1950 ± 203 versus 2317 ± 376 ml per min) and mean arterial pressure (138 ± 6 versus 151 ± 7 mm Hg), whereas heart rate did not change. Partial balloon obstruction of the superior mesenteric artery caused similar changes in splanchnic hemodynamics to those of vasopressin infusions into the superior mesenteric artery, but without the potential deleterious effects of vasopressin on systemic hemodynamics.