Direction Of Portal Blood Flow Research Articles

Possible Cause of Liver Failure in Patient with Dengue Shock Syndrome

Possible Cause of Liver Failure in Patient with Dengue Shock Syndrome

Suivi échographique des patients cirrhotiques

Ultrasonography seems to satisfy the necessary conditions of a monitoring examination: 1) it is repeatable, reliable, noninvasive, and inexpensive; 2) its results can directly influence the therapeutic attitude and even the prognosis and the survival of patients with liver cirrhosis; 3) the use of Doppler is essential (partial thrombosis, velocity and direction of portal blood flow); and 4) the description of the portal vein is necessary before any surgery in a cirrhotic patient. All these items must be systematically noted and standardized to have an effective follow-up of the cirrhotic patients.

Value of duplex doppler ultrasonography in non-invasive assessment of children with chronic liver disease

to investigate the value of duplex Doppler ultrasonography (US) in the assessment of the hemodynamics of the portal and hepatic veins in a cohort of children with chronic liver disease (CLD) and to detect any relationship between the US changes, etiology and severity (or stage) of CLD. we prospectively enrolled 25 children with biopsy-proven CLD. Thirteen had cirrhosis (aged 8.9 ± 2.0 years) and 12 had chronic hepatitis (aged 9.3 ± 2.3 years). Gray scale and color-coded duplex Doppler US were performed for all, as well as 30 healthy age and sex-matched controls. Findings were correlated with clinical, laboratory and histopathological characteristics. prominent caudate lobe was detected in 100% of cirrhotics, but none of the chronic hepatitis or controls. Thickened lesser omentum and loss of the triphasic waveform of the hepatic vein were present in 69.2% and 53.8% of cirrhotics vs 33.3% and 8.3% of chronic hepatitis respectively. Portal vein flow velocity was significantly lower (P < 0.0001) and the congestion index was significantly higher (P < 0.005) in both patient groups compared to controls. Child-Pugh's staging showed a positive correlation with both abnormal hepatic vein waveform and direction of portal blood flow; and a negative correlation with both hepatic and portal vein flow velocities. No correlation with the etiology of CLD could be detected. duplex Doppler added to grayscale US can detect significant morphologic and portal hemodynamic changes that correlate with the severity (stage) of CLD, but not with etiology.

Pictorial review: Colour Doppler ultrasound flow patterns in the portal venous system.

Doppler ultrasound is a well established method for assessment of the portal venous system to detect the direction of portal blood flow. It is helpful for non-invasive diagnosis of intra-abdominal portosystemic shunts, especially in patients with cirrhosis. Less attention has been paid to other influences on portal venous flow, e.g. tricuspid regurgitation, increased hepatic out-flow resistance, respiratory cycle. The aim of this pictorial review is to describe the spectrum of physiological and pathological Doppler ultrasound flow patterns in the portal venous system.

Arterioportal fistulas in patients with liver cirrhosis: usefulness of color Doppler US for screening.

To evaluate the usefulness of routine ultrasonographic (US) evaluation of the hepatic arterial resistive and pulsatility indexes and of the direction of portal venous blood flow for the diagnosis of intrahepatic arterioportal fistulas (APFs) in patients with liver cirrhosis. In all patients with cirrhosis examined at one center over 4 years, the resistive (RI) and the pulsatility (PI) indexes in the right and left branches of the hepatic artery were evaluated with Doppler US. An APF was suspected when an RI decrease of at least 20% and a PI decrease of at least 30% were present in one hepatic lobe relative to values in the other lobe and portal blood flow in the lobe with the decreased values was reversed. The RI and PI in patients with an APF were compared with those in 75 patients with cirrhosis and without APFs at angiography. Seven patients with an APF were identified. APFs suspected at Doppler US were always confirmed with angiography. The percent differences +/- SD in the RI and the PI between the two intrahepatic branches of the hepatic artery in patients with versus in patients without an APF were as follows: RI, 35% +/- 6 (range, 27%-42%) versus 5% +/- 4 (range, 0%-15%) (P: <.001); PI, 50% +/- 5 (range, 41%-58%) versus 11% +/- 7 (range, 0%-26%) (P: <.001). The intrahepatic arterial resistive and pulsatility indexes and the direction of portal blood flow should be evaluated in routine screening for APFs in patients with liver cirrhosis.

Does the direction of portal blood flow determine outcome with small-diameter prosthetic H-graft portacaval shunt?

Background. Partial portal decompression, as attained by small-diameter prosthetic H-graft portacaval shunting, continues to gain popularity because of favorable outcomes. This study was undertaken to determine whether the direction of preshunt or postshunt portal blood flow or reversal in the direction of portal flow occurred with shunting effect outcome after small-diameter prosthetic H-graft portacaval shunt. Methods. In 56 consecutive patients the direction of portal flow was determined before and after shunting. The direction of portal blood flow before and after shunting and changes in the direction of portal flow that occur with shunting were correlated with 30-day and 1-year survival, as well as with the rate of postshunt encephalopathy. Results. Portal pressures significantly decreased in all with shunting. Whether or not stratified by Child's classification, neither the preshunt nor postshunt direction of portal flow affected 30-day or 1-year survival or incidence of encephalopathy. Eleven patients (significant at p < 0.001, Fisher's exact test) had reversal of portal blood flow with shunting without an increase in 30-day or 1-year survival or incidence of encephalopathy. Conclusions. Small-diameter prosthetic H-graft portacaval shunts significantly reduce portal pressure and lead to reversal of portal flow in significant numbers. Significant hepatic dysfunction is uncommon after shunting. Neither the direction of preshunt or postshunt portal blood flow nor the reversal of portal blood flow with shunting has an effect on clinical outcome after small-diameter prosthetic H-graft portacaval shunt.

Direction or Reversal of Preshunt Portal Blood Flow as Determinants of Outcome up to 1 Year after Small-Diameter Prosthetic H-Graft Portacaval Shunt

Partial portal decompression (PPD) is gaining popularity in the treatment of portal hypertension. We have achieved PPD in over 80 patients by utilizing an 8-mm prosthetic H-graft portacaval shunt (HGPCS). We have been pleased with the infrequency of encephalopathy and liver failure after shunting. While maintenance of portal blood flow would presumably play a role in outcome after shunting, changes in portal hemodynamic occurring within the first year after shunting are generally unknown. In 31 patients (Child's class 6% A, 61% B, 32% C) of an average age of 55 ± 13.3 (SD) years undergoing HGPCS, clinical outcome was prospectively evaluated relative to the direction of portal blood flow determined before and after shunting and at 1 year after shunting using color-flow Doppler ultrasound. Preshunt hepatopetal flow reversed in 2/29 (7%) patients with shunting and in an additional 5/27 (18%) patients by 1 year after shunting. Death (due to alcoholism in 1, old age in 1) and encephalopathy (Child's class A = 1, B = 2, C = 1) were uncommon by 1 year after shunting. Eighty-one percent had excellent outcome (alive without encephalopathy or rebleeding) at 1 year. Though preshunt hepatopetal flow is generally maintained postshunt and after one year, maintenance of hepatopetal flow does not ensure an excellent outcome and reversal of hepatopetal flow does not predispose to a suboptimal outcome. Outcome up to 1 year after HGPCS is not determined by direction or reversal of portal blood flow.

The effect of small diameter H-graft portacaval shunts on portal blood flow

BACKGROUND: Small-diameter prosthetic H-graft T he traditional end-to-side portacaval shunt is assoportacaval shunts have been shown to promote ciated with a prohibitive risk of severe hepatic dyspreservation of total hepatic blood flow relative to function and, therefore, has been abandoned as a large-diameter H-graft shunts. Nonetheless, spefirst choice treatment option in the management of variceal cific changes in portal hemodynamics occurring hemorrhage due to portal hypertension.’ This shunt diverts with smalldiameter H-graft shunting are unknown. all portal blood flow from the liver and achieves complete This study was undertaken to evaluate changes in portal decompression. Partial portal decompression incomportal flow that occur with these shunts. pletely decompresses the portal vein and allows prograde porMETHODS: Portal vein and inferior vena cava (IVC) tal blood flow.* Different extremes of partial portal decomblood flow were determined intraoperatively in 36 pression have been compared through study of largeand consecutive adults before and after prosthetic Hsmall-bore prosthetic H-graft portacaval shunts.3*4 Compared graft portacaval shunting using color-flow with large-bore shunts, small-bore shunts less completely deDoppler ultrasound. Postshunt measurements compress the portal vein and divert less nutrient hepatic were made immediately cephalad and caudad to blood flow. The relative maintenance of nutrient hepatic the shunt. Comparisons were undertaken using a blood flow by small-diameter prosthetic H-graft portacaval paired Student’s t-test with 95% confidence. shunts is presumed to be the basis by which these shunts RESULTS: Portal pressures decreased in all (P lead to superior clinical outcomes.’ <O.OOl), but never to normal. Postshunt portal Surprisingly, hemodynamic changes in the portal system ocflow cephalad and caudad to the shunt were not curring with small-diameter prosthetic H-graft portacaval different from preshunt flow (P = 0.09, P = 0.26, . shunts are poorly understood. Studies have been undertaken respectively), although they were different from to determine changes in portal and hepatic blood flo~,~ each other (P = 0.004). Postshunt IVC flow changes in the direction of portal blood flow:” and changes cephalad to the shunt was greater than caudad in portal pressures with small-diameter H-graft shunting.*s IVC flow (P = 0.004) and greater than preshunt The results of these studies are often conflicting and difficult IVC flow (P <O.OOl), reflecting high flow through to correlate with clinical outcomes, leaving many questions the shunt into the IVC. about portal hemodynamic changes with H-graft shunting. CONCLUSIONS: Small-diameter prosthetic H-graft This study was undertaken to measure portal vein and inportacaval shunts divert a significant amount of ferior vena cava (IVC) blood flow to determine the size of blood from the portal vein and significantly dethe reduction in portal blood flow that occurs with partial crease portal pressures. The decreases in portal portal decompression attained through small-diameter prospressures with shunting are significant whereas thetic H-graft portacaval shunting and to determine the volchanges in portal blood flow into the liver are ume of blood shunted from the portal system. Our hypotheses not. These findings help explain the low inciin undertaking this study were that portal blood flow into dence of variceal rebleeding and hepatic dysthe liver was well maintained after partial portal decomfunction after these shunts. Am J Surg. 1996; 171 :154-l 57. pression achieved by small-diameter prosthetic H-graft shunting, that loss of portal blood flow into the liver was small compared with reduction in portal pressures, and that the volume of blood shunted from the portal system was large, although compensated for by an increase in blood flow into the portal system.

Budd-Chiari syndrome: dynamic CT.

A retrospective multi-institutional study was carried out on a series of 38 patients with histologically proved Budd-Chiari syndrome: Five patients had acute disease, and 33 had subacute or chronic disease. All patients underwent dynamic CT scanning. Angiography was performed in 20 cases, inferior cavography in 22, and wedge-hepatic venography in 16. In all acute cases, CT showed global liver enlargement with diffuse hypodensity on plain scans and patchy enhancement after contrast material injection. Thrombosis of the three main hepatic veins was always demonstrated. In subacute or chronic disease, plain CT scans showed abnormalities of liver morphology and hypodensity either in atrophic areas (19 cases) or in the periphery of the liver (eight cases). With dynamic CT, patchy enhancement was present in 28 cases. Correlation with angiography in 15 cases revealed a normal portal blood flow in enhanced areas and an inversed portal blood flow in atrophic areas. Different morphologic and enhancement patterns on CT scans could be related to the direction of portal blood flow, which changes with different stages of Budd-Chiari syndrome.

5 - Ultrasonography in Portal Hypertension

High resolution real time ultrasound is a non-invasive method of evaluating patients with suspected portal hypertension. The portosystemic collateral most frequently identified is the dilated coronary vein and its associated gastro-oesophageal varices. Other collaterals that can be seen include: gastrorenal, splenorenal, paraduodenal, periportal, pelvic and retroperitoneal varices along with a recanalized umbilical vein and ductus venosus. Using duplex doppler ultrasound, the rate and direction of portal blood flow can be ascertained. Sonography is better than barium studies in assessing whether gastro-oesophageal varices are present, however, it is not as sensitive as endoscopy, laparoscopy or portography.

Hemodynamic guidelines for surgical therapy of portal hypertension.

A prospective study of 98 patients with portal hypertension who hemorrhaged revealed that certain hemodynamic parameters were valuable in confirming the cause of cirrhosis, aiding in the selection of patients best suited for a selective distal splenorenal shunt, and in providing an estimate of prognosis. The presence of a pressure gradient of 4 mmHg or more between the right atrium and inferior vena cava was observed only in patients with alcoholic cirrhosis. The shape of the "pull-back" tracing between the wedge and free hepatic vein positions was "smooth" in postnecrotic disease and "lumpy" in alcoholic disease. The ratio of the aortic diastolic pressure divided by the hepatic (vein) wedge pressure segregated patients by cause and direction of portal blood flow.

Spontaneous Reversal of Portal Blood Flow

Because of its presumed serious clinical significance, we made an analysis of the evidence for and against the occurrence of spontaneous reversal of portal flow in cirrhosis of the liver. We examined the evidence obtained from manometric studies, radioactive tracer studies, radiologic studies, and actual measurements of magnitude and direction of portal blood flow. Concerning manometric studies, we introduced a physical analysis, based on first principles, which demonstrates that the occluded portal pressures cannot be used to construct a hydraulic gradient for portal flow. Similarly, we examined the weakness of the evidence derived from radioactive tracer and radiologic studies and, in the latter, the drastically opposite results reported by different investigators. Finally, we found that actual measurements of magnitude and direction of portal flow provide impressive evidence against the occurrence of spontaneous reversal of portal flow in cirrhosis. We conclude that unless new and convincing evidence is provided, it may not serve the best interests of medicine and of our patients to continue accepting spontaneous reversal of portal flow in cirrhosis as if it were a proven phenomenon.