Mesenteric VeinsMesenteric Vascular OcclusionPortal VeinMesenteric ArteriesMesenteric Artery, SuperiorSplenic VeinPortal SystemPancreaticoduodenectomySplanchnic CirculationIliac VeinMesenteric Artery, InferiorVeinsHypertension, PortalVenous ThrombosisHepatic VeinsTomography, X-Ray ComputedArteriesVena Cava, InferiorThrombosisPancreatic NeoplasmsGastrointestinal HemorrhageTreatment OutcomeRenal VeinsMuscle, Smooth, VascularFemoral VeinCeliac ArterySaphenous VeinSuperior Mesenteric Artery SyndromeVasoconstrictionNorepinephrinePulmonary ArteryRenal ArteryVisceraCerebral ArteriesFemoral ArteryVasodilationVaricose VeinsCarotid ArteriesVena Cava, SuperiorSuperior ColliculiPulmonary VeinsDogsBasilar ArteryMuscle ContractionVasoconstrictor AgentsBiological FactorsIofetamineTime FactorsVasodilator AgentsJugular VeinsEndothelium, Vascular