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Portal Vein Pressure (portal + vein_pressure)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Selective Hemi-Portocaval Shunt Based on Portal Vein Pressure for Small-for-Size Graft in Adult Living Donor Liver Transplantation

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2008
T. Yamada
We developed an algorithm of graft selection in which left lobe donation is considered primarily if the graft-to-recipient weight ratio (GRWR) is estimated to be greater than 0.6% in preoperative volumetry with utilization of a hemi-portocaval shunt (HPCS) based on portal vein pressure (PVP) more than 20 mmHg at the time of laparotomy. A total of 11 consecutive adult living donor liver transplantations with small-for-size graft according to our graft selection algorithm were performed between December 2005 and August 2007. Ten patients required HPCS using a vein graft all survived without small-for-size syndrome (SFSS) and shunt complications with a median follow-up of 296 days. One patient without HPCS died of chronic vascular rejection. In all cases, PVP were regulated successfully under 20 mmHg by HPCS. Graft volume reached in mean 84.3% of standard liver volume in right lobe grafts and mean 95.4% in left lobe grafts at 3 months after liver transplantation. Actuarial rate of shunt patency at 1, 3, 6 months and 1 year were 80%, 55%, 26% and 20%, respectively. Selective HPCS based on PVP is an effective procedure and results in excellent patient and graft survival with avoidance of SFSS in grafts greater than 0.6% of GRWR. [source]

Effect of porto-systemic shunting on NOS expression after extended hepatectomy in rats

HEPATOLOGY RESEARCH, Issue 1 2009
Hironori Hayashi
Aim:, Several surgical procedures have been developed for reducing portal vein pressure to prevent postoperative liver injury. Nitric oxide synthase expression (NOS) induced by elevation of portal vein pressure is thought to play an important role in liver regeneration, but the details are not well understood. Methods:, Rats in the control group and in the subcutaneous splenic transposition (SST) group underwent 90% partial hepatectomy. Survival and portal vein pressure were analyzed. The serum IL-6 and TNF-, levels were measured by enzyme-linked immunosorbent assay (ELISA). Hepatocyte proliferation and apoptosis 12 hours after hepatectomy were analyzed immunohistochemically. The protein and messenger RNA expression of inducible and endothelial NOS were analyzed using Western blotting and quantitative reverse transcriptase polymerase chain reaction, respectively. Results:, The survival rate of the SST group was significantly higher. Portal vein pressure, TNF-, level and the apoptotic index were significantly lower in the SST group. Twelve hours after surgery, liver inducible NOS (iNOS) protein expression was significantly lower in the SST group. However, protein expression of endothelial NOS was not significantly different between the groups. Conclusion:, Inducible NOS expression after extended hepatectomy is related to the effects of porto-systemic shunting on the splanchnic circulation. Also, iNOS induction and concomitant nitric oxide generation appear to participate in the cytotoxicity of excessive portal pressure after extended hepatectomy. [source]

Flow in Lymphatic Networks: Interaction between Hepatic and Intestinal Lymph Vessels

MICROCIRCULATION, Issue 4 2001
RANDOLPH H. STEWART
ABSTRACT Objective: Lymph from both the liver and intestine flows into the cisterna chyli. We hypothesized that increasing liver lymph flow would increase cisterna chyli pressure and, thereby, decrease intestinal lymph flow, potentiating intestinal edema formation. Methods: Anesthetized dogs were instrumented to measure and manipulate portal vein pressure and cisterna chyli pressure. The effects of directly increasing portal pressure with and without directly increasing cisterna chyli pressure on intestinal wet-to-dry ratio and intestinal ascites formation rate were determined. Target values for portal and cisterna chyli pressures were determined following elevation of inferior vena caval pressure to levels seen in patients with obstructive caval disease. Results: Direct elevation of portal pressure (Pport) alone to 17.5 mm Hg caused a significant increase in intestinal wet-to-dry ratio (3.98 ± 0.24 vs. 3.40 ± 0.43) and the rate of ascites formation (0.36 ± 0.12 vs. 0.05 ± 0.03 mL/g dry wt/h). Simultaneous direct elevation of cisterna chyli pressure to 6.0 mm Hg and Pport to 17.5 mm Hg caused further increases in intestinal wet-to-dry ratio (5.52 ± 1.20) and ascites formation (0.57 ± 0.11 mL/g dry wt./h). Conclusions: Inferior vena caval hypertension increases liver lymph flow that elevates cisterna chyli pressure, which inhibits intestinal lymph flow and augments intestinal edema formation. [source]

Effectiveness of porto-intracaval shunt to reduce the negative effects of portal and caval clamping in the rabbit

MICROSURGERY, Issue 4 2001
Gaetano La Greca M.D., Ph.D.
In performing experimental liver surgery, it is difficult to prolong anhepatic time because the animals do not tolerate prolonged portal and caval clamping. To counteract prolonged venous stasis, the authors previously developed a simple porto-intracaval shunt. The shunt consists of a self-constructed inverted Y silicone tube. The effectiveness of this shunt was studied comparing two groups of 10 rabbits with shunt (S) versus those with clamped portal and inferior caval vein (C). In the group of rabbits that underwent porto-intracaval shunt, the results concerning intraoperative mortality, intraoperative increase in distal portal vein pressure, and incidence of the histologic signs of gut damage were clearly improved. The proposed porto-intracaval shunt was therefore effective in reducing some principal negative effects of portal and caval clamping. This type of porto-intracaval shunt can be therefore useful allowing improvement of experimental models concerning liver surgery in little animals. In chirurgia sperimentale del fegato è difficile prolungare il tempo anepatico dato che gli animali non tollerano un clampaggio portale e cavale prolungato. Gli Autori hanno precedentemente sviluppato un semplice shunt porto-intracavale con l'intento di ovviare alla stasi venosa prolungata. Lo shunt è costituito da un tubo di silicone a forma di Y invertita. Nel presente studio viene analizzata l'efficacia di questo shunt confrontando un gruppo di dieci conigli con shunt (S) rispetto al gruppo sottoposto invece al clampaggio della vena porta e della vena cava inferiore (C). I risultati riguardo mortalità intraoperatoria, incremento intraoperatorio della pressione portale distale e presenza e distribuzione di segni istologici di danno intestinale sono chiaramente migliori nel gruppo con shunt intra-porto cavale. Lo shunt porto-intracavale proposto è risultato realmente efficace nel ridurre alcuni dei principali effetti negativi del clampaggio portale e cavale. Questo tipo di shunt porto-intra cavale può essere quindi utile per migliorare le possibilità e i modelli di chirurgia sperimentale del fegato nei piccoli animali. © 2001 Wiley-Liss, Inc. MICROSURGERY 21:179,182 2001 [source]

Selective Hemi-Portocaval Shunt Based on Portal Vein Pressure for Small-for-Size Graft in Adult Living Donor Liver Transplantation

NG -NITRO- l -ARGININE METHYL ESTER POTENTIATES ANAPHYLACTIC VENOCONSTRICTION IN RAT PERFUSED LIVERS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2006
Toshishige Shibamoto
SUMMARY 1The effects of the nitric oxide (NO) synthase inhibitor NG -nitro- l -arginine methyl ester (l -NAME) on anaphylaxis-induced venoconstriction were examined in rat isolated livers perfused with blood-free solutions in order to clarify the role of NO in anaphylactic venoconstriction. 2Rats were sensitized with ovalbumin (1 mg) and, 2 weeks later, livers were excised and perfused portally in a recirculating manner at a constant flow with Krebs',Henseleit solution. The antigen (ovalbumin; 0.1 mg) was injected into the reservoir 10 min after pretreatment with l-NAME (100 mmol/L) or d -NAME (100 mmol/L) and changes in portal vein pressure (Ppv), hepatic vein pressure (Phv) and perfusate flow were monitored. In addition, concentrations of the stable metabolites of NO ( and ) were determined in the perfusate using an HPLC,Griess system. 3The antigen caused hepatic venoconstriction, as evidenced by an increase in Ppv from a mean (SEM) baseline value of 7.7 ± 0.1 cmH2O to a peak of 21.4 ± 1.1 cmH2O at 3 min in d -NAME-pretreated livers. Pretreatment with l-NAME augmented anaphylactic venoconstriction, as reflected by a higher Ppv (27.4 ± 0.8 cmH2O) after antigen than observed following d -NAME pretreatment. The addition of l -arginine, a precursor for the synthesis of NO, reversed the augmentation of anaphylactic venoconstricion by l -NAME. This suggests that hepatic anaphylaxis increased the production of NO, which consequently attenuated anaphylactic venoconstriction. However, perfusate NOx levels did not increase significantly after antigen in livers pretreated with either l -NAME or d -NAME. 4In conclusion, l -NAME potentiates rat anaphylactic hepatic venoconstriction, suggesting that NO contributes to the attenuation of the venoconstriction. However, this functional evidence was not accompanied by corresponding changes in perfusate NOx concentrations. [source]