title: Magnetic resonance imaging catheter stress haemodynamics post-Fontan in hypoplastic left heart syndrome.
abstract: OBJECTIVE
  Exercise limitation is common post-Fontan. Hybrid X-ray and magnetic resonance imaging (XMR) catheterization allows haemodynamic assessment by means of measurement of ventricular volumes and flow in major vessels with simultaneous invasive pressures. We aim to assess haemodynamic response to stress in patients with hypoplastic left heart syndrome (HLHS) post-Fontan.
  
  
  RESULTS
  Prospective study of 13 symptomatic children (NHYA 2) with HLHS post-Fontan using XMR catheterization. Three conditions were applied: baseline (Stage 1), dobutamine at 10 µg/kg/min (Stage 2), and dobutamine at 20 µg/kg/min (Stage 3). Seven consecutive patients received inhaled nitric oxide (iNO) at peak stress. Control MRI data were from normal healthy adults. In the HLHS patients, baseline mean pulmonary vascular resistance (PVR) was 1.51 ± 0.59 WU m(2) and aortopulmonary collateral flow was 17.7 ± 13.6% of systemic cardiac output. Mean right ventricular end-diastolic pressure was 6.7 ± 2.5 mmHg which did not rise with stress. Cardiac index (CI) increased at Stage 2 in HLHS (40%) and controls (61%) but continued to increase at Stage 3 only in controls (19%) but not in HLHS. The blunted rise in CI in HLHS was due to a continuing fall in end-diastolic volume throughout stress, with no significant change in PVR or CI at peak stress in response to iNO.
  
  
  CONCLUSIONS
  Cardiac output post-Fontan in HLHS at peak stress is blunted due to a limitation in preload which is not responsive to inhaled pulmonary vasodilators in the setting of normal PVR.
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Kuberan
authors.initials: K
authors.lastname: Pushparajah
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: James K
authors.initials: JK
authors.lastname: Wong
authors.affiliation: Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Hannah R
authors.initials: HR
authors.lastname: Bellsham-Revell
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Tarique
authors.initials: T
authors.lastname: Hussain
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Israel
authors.initials: I
authors.lastname: Valverde
authors.affiliation: Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Aaron
authors.initials: A
authors.lastname: Bell
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Aphrodite
authors.initials: A
authors.lastname: Tzifa
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Gerald
authors.initials: G
authors.lastname: Greil
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: John M
authors.initials: JM
authors.lastname: Simpson
authors.affiliation: University of Nebraska/Creighton University Joint Division of Pediatric Cardiology, Omaha, NE, USA.
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
authors.affiliation: Division of Imaging Sciences, King's College London BHF Centre, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK Paediatric Cardiovascular Sciences, Rayne Institute, King's College London and Evelina London Children's Hospital, Westminster Bridge Road, London SE1 7EH, UK reza.razavi@kcl.ac.uk.
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D006328:Cardiac Catheterization / Q000379:methods; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D025401:Echocardiography, Stress; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000000981:diagnostic imaging* / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D011379:Prognosis; D018570:Risk Assessment; D012737:Sex Factors; D014655:Vascular Resistance / Q000502:physiology*
keywords: Fontan; MRI; dobutamine; hypoplastic left heart syndrome; pulmonary vascular resistance