Brain magnetic resonance imaging characteristics in dogs and cats with congenital portosystemic shunts.

Animals with a portosystemic shunt (PSS) often have neurologic abnormalities. Diagnostic imaging, including brain magnetic resonance (MR) imaging, is not performed routinely in these animals. In this study, brain MR images were obtained in 13 dogs and three cats with a PSS, and in 15 dogs and five cats that were neurologically normal and used as controls. All animals with a PSS had widened sulci. In addition, 10 out of 13 dogs with a PSS and one out of three cats with a PSS had hyperintense focal areas in the lentiform nuclei on T1-weighted (T1W) images, which did not enhance after intravenous gadolinium. Following surgical correction of the PSS, MR imaging examinations were repeated in one dog and one cat. The hyperintensity of the lentiform nuclei had decreased. This study indicates that MR imaging findings of widened sulci and hyperintensity of the lentiform nuclei on T1W images may be found in dogs and cats with a PSS.

Utilidad del Doppler color y pulsadoen la valoración de los shunts portosistémicosquirúrgicos en la edad pediátrica / Usefulness of color and pulsed Dopplers in the evaluation of surgical portosystemic shunts in pediatric patients

Los shunts portosistémicos se realizan para paliar la hipertensión portal sintomática o para descomprimir la vascularización hepática en pacientes con síndrome de Budd-Chiari. La mayoría de los shunts portosistémicos quirúrgicos pueden estudiarse adecuadamente mediante ecografía complementada con Doppler color y pulsado si se comprende la hemodinámica de los procedimientos quirúrgicos. Este artículo muestra la utilidad y limitaciones de la ecografía duplex Doppler en la evaluación de los shunts portosistémicos realizados a pacientes pediátricos. El Doppler pulsado proporciona información sobre la naturaleza y dirección del flujo sanguíneo y el Doppler color es capaz de mostrar directamente el shunt y, en la mayoría de los casos, permite localizar las anastomosis. Los tipos de shunts que se muestran incluyen esplenorenal proximal y distal, portocava y mesocava. Se ilustran los tipos de conexiones vasculares y se muestra la dirección posquirúrgica esperable del flujo en los vasos sanguíneos implicados. Se discute la técnica ecográfica y los criterios para determinar la permeabilidad vascular.Así mismo se enfatizan las ventajas, limitaciones y dificultades diagnósticas de las distintas modalidades del Doppler (AU)

Survival and quality of life after portal blood flow preserving procedures in patients with portal hypertension and liver cirrhosis.

Between 1979 and 1991, 156 patients with histologically proven liver cirrhosis, good liver function, and bleeding portal hypertension underwent operation with portal blood flow preserving procedures (selective shunts: 101; Sugiura-Futagawa: 55). Long-term results of the procedures and the quality of life of the 145 patients who survived the operation were studied. During the observation period (range 3 to 156 months), 28 patients died. The main causes of death were liver failure and hepatoma. Twenty-three patients were lost for follow-up. Twenty-six patients (18%) developed 1 or more encephalopathic episodes. Four patients (3%) experienced rebleeding. One hundred eight patients (74%) had a good quality of life, and 26 (18%) had a poor quality of life. Eleven (15%) of 73 patients with a history of alcoholism continued drinking. Five-year survival for the selective shunt group was 81% and for the devascularization group was 83%. In 81% of the patients, portal blood flow was maintained. It is concluded that both procedures are effective in the long-term. Most patients are able to rehabilitate from the use of alcohol, and most of them have a good quality of life. For patients with good liver function (whose main problem is bleeding), surgery is the best choice of treatment.

The role of portosystemic shunts for variceal bleeding in the liver transplantation era.

OBJECTIVE: To review our experience with portosystemic shunts during the era of liver transplantation at the Mayo Clinic to provide insight into the selection of patients for these procedures. DESIGN: We reviewed the charts of a cohort of 57 patients who underwent portosystemic shunting between 1985 and 1990 for the management of variceal bleeding. A follow-up survey by letter and telephone was also conducted. SETTING: The Mayo Clinic, a tertiary referral center. PATIENTS: These patients were not considered transplantation candidates at the time of the shunt because of active alcoholism, extensive portal vein thrombosis, coexistent myelodysplastic syndromes, or malignant neoplasms. INTERVENTION: Portosystemic shunts; the exact type was at the surgeon's discretion. OUTCOME: Survival after shunt surgery among patients with various liver diseases. RESULTS: Twenty-two patients died during follow-up after being shunted for bleeding, and one of the shunted patients subsequently required liver transplantation. Comparison of Kaplan-Meier survival curves between various groups of patients indicated that patients who were actively alcoholic had a poorer chance of survival (P < .003) than did those who were abstinent. Patients with portal vein obstruction or chronic cholestatic liver disease appeared to do better after shunt surgery than did patients with other causes of portal hypertension. Other factors such as age, Child-Pugh score, or presence of malignant neoplasms did not reliably predict outcome from portosystemic shunts. CONCLUSIONS: In well-selected patients who may not be deemed candidates for liver transplantation, portacaval shunts can be effectively employed to prevent bleeding from esophageal varices that are resistant to obliteration by sclerotherapy.

Which portosystemic shunt is best?

No single shunt operation is ideal for all patients or all circumstances. The selective distal splenorenal shunt is preferred for the majority of patients, because it has the potential to preserve hepatic portal perfusion. Most evidence suggests that the distal splenorenal shunt is followed by a lower frequency of encephalopathy than is any type of nonselective shunt. Although theoretically attractive, the small-diameter interposition portacaval shunt has not yet been subjected to the scrutiny of controlled trials.

[Hemodynamic consequences of portal decompression: which is the optimal shunt?]. / Hämodynamische Konsequenzen der portalen Decompression: Welches ist der optimale Shunt?

Increased sinusoidal resistance in cirrhosis results in a decrease of the portal and a compensatory increase of the arterial blood supply to the liver. With increasing vascular resistance and development of extrahepatic collaterals stagnation and even reversion of the portal blood flow may occur. In the latter condition, the arterial blood leaves the liver through two routes: 1) through the sinusoids and the hepatic veins, and 2) through the portal vein. Experimental and clinical studies revealed that the arterio-portal pathway is metabolically inferior to the regular arterio-hepatic-venous pathway. This suggests a decrease in liver function with an increased incidence of hepatic encephalopathy (HE) in patients with reversed portal blood flow. Based on these findings, surgical shunts may be classified according to their effect on the arterial liver perfusion. The end-to-side shunt and the distal splenorenal shunt (DSRS) do not cause diversion of the arterial liver perfusion. In contrast, side-to-side shunts, with the portal vein available as an outflow tract, consistently lead to diversion of the arterial blood supply resulting in reversed portal blood flow. Thus, side-to-side shunts are supposed to have an increased incidence of HE due to decreased liver function. This hypothesis is supported by 7 controlled and randomized studies which reveal comparable results of end-to-side shunts and DSRS but significant disadvantages of side-to-side shunts compared to DSRS.