Pulmonary ArteryPulmonary CirculationArteriesBlood Flow VelocityHypertension, PulmonaryCerebral ArteriesFemoral ArteryRegional Blood FlowMiddle Cerebral ArteryCarotid ArteriesBronchial ArteriesOphthalmic ArteryMesenteric Artery, SuperiorMesenteric ArteriesUmbilical ArteriesHemodynamicsBlood PressurePulsatile FlowUltrasonography, DopplerRenal ArteryCatheterization, Swan-GanzVascular ResistanceRadial ArteryUltrasonography, Doppler, PulsedVasoconstrictionCarotid Artery, InternalCerebrovascular CirculationAnoxiaBasilar ArteryBrachial ArteryUltrasonography, Doppler, ColorUltrasonography, Doppler, TranscranialUterusPulmonary Wedge PressureVasodilationCardiac OutputMuscle, Smooth, VascularCoronary Artery BypassUterine ArteryVasodilator AgentsCoronary VesselsIliac ArterySubclavian ArteryVertebral ArteryCarotid Artery, CommonMammary ArteriesDogsEndothelium, VascularHeart RateCoronary CirculationCardiac CatheterizationUltrasonographyUltrasonography, PrenatalCarotid Artery, ExternalFetal Growth RetardationPregnancyTime FactorsVasoconstrictor AgentsCarotid Artery DiseasesOxygenSplenic ArteryCircle of WillisPulmonary EmbolismTreatment OutcomeAngiographyNitric OxideLungHypertrophy, Right VentricularHepatic ArteryArterial PressurePulmonary Valve StenosisMonocrotalineHeart Defects, CongenitalSwinePulmonary AtresiaGestational AgeLaser-Doppler FlowmetryHeart Septal Defects, VentricularHypocapniaMephentermineProspective StudiesSplanchnic CirculationVascular NeoplasmsCeliac ArteryArterial Occlusive DiseasesAltitudeTetralogy of FallotTomography, X-Ray ComputedCoronary Vessel AnomaliesDuctus ArteriosusPlacental CirculationMyocytes, Smooth MuscleRheologyArterio-Arterial FistulaAneurysmSheepConstriction, PathologicPulmonary VeinsVentricular Function, RightNitroglycerin