Arteriovenous Shunt, SurgicalArteriovenous FistulaCranial SinusesCentral Nervous System Vascular MalformationsArteriovenous MalformationsCerebral VeinsArteriovenous AnastomosisIntracranial Arteriovenous MalformationsFluorocarbon PolymersBleeding TimeDura MaterPhenindioneEmbolization, TherapeuticVentriculoperitoneal ShuntThrombosisCerebrospinal Fluid ShuntsSkin TemperatureHepatic ArteryCerebral AngiographyJugular VeinsPapioPortasystemic Shunt, SurgicalRegional Blood FlowAngiographyPortacaval Shunt, SurgicalPeritoneovenous ShuntPlatelet AggregationDogsHydrocephalusHypertension, PortalEsophageal and Gastric VaricesHepatic EncephalopathyHeart Septal Defects, AtrialSplenic VeinPortal SystemPortal VeinAscitesHeart Septal DefectsGastrointestinal HemorrhageHydrocephalus, Normal PressureRenal VeinsPulmonary CirculationForamen Ovale, PatentHeart Bypass, RightAdenoma, Liver CellLiver NeoplasmsFocal Nodular HyperplasiaLiver DiseasesHemangiomaCarcinoma, Hepatocellularalpha-Fetoproteins