Retinal VeinRetinal Vein OcclusionRetinal ArteryConstriction, PathologicSwine, MiniatureVeinsSaphenous VeinPortal VeinVaricose VeinsFemoral VeinPulmonary VeinsJugular VeinsMesenteric VeinsRenal VeinsIliac VeinUmbilical VeinsHepatic VeinsPopliteal VeinSubclavian VeinSplenic VeinCerebral VeinsBrachiocephalic VeinsAzygos VeinAxillary VeinVenous ThrombosisBundle-Branch BlockPhlebographyVenous InsufficiencyGraft Occlusion, VascularUltrasonography, Doppler, DuplexVena Cava, InferiorPhylogenyVascular PatencyTreatment OutcomeTime FactorsVascular Surgical ProceduresLeg