title: Noninvasive estimation of PA pressure, flow, and resistance with CMR imaging: derivation and prospective validation study from the ASPIRE registry.
abstract: OBJECTIVE
  The aim of this study was to develop a composite numerical model based on parameters from cardiac magnetic resonance (CMR) imaging for noninvasive estimation of the key hemodynamic measurements made at right heart catheterization (RHC).
  
  
  BACKGROUND
  Diagnosis and assessment of disease severity in patients with pulmonary hypertension is reliant on hemodynamic measurements at RHC. A robust noninvasive approach that can estimate key RHC measurements is desirable.
  
  
  METHODS
  A derivation cohort of 64 successive, unselected, treatment naive patients with suspected pulmonary hypertension from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Centre) Registry, underwent RHC and CMR within 12 h. Predicted mean pulmonary arterial pressure (mPAP) was derived using multivariate regression analysis of CMR measurements. The model was tested in an independent prospective validation cohort of 64 patients with suspected pulmonary hypertension. Surrogate measures of pulmonary capillary wedge pressure (PCWP) and cardiac output (CO) were estimated by left atrial volumetry and pulmonary arterial phase contrast imaging, respectively. Noninvasive pulmonary vascular resistance (PVR) was calculated from the CMR-derived measurements, defined as: (CMR-predicted mPAP - CMR-predicted PCWP)/CMR phase contrast CO.
  
  
  RESULTS
  The following composite statistical model of mPAP was derived: CMR-predicted mPAP = -4.6 + (interventricular septal angle × 0.23) + (ventricular mass index × 16.3). In the validation cohort a strong correlation between mPAP and MR estimated mPAP was demonstrated (R(2) = 0.67). For detection of the presence of pulmonary hypertension the area under the receiver-operating characteristic (ROC) curve was 0.96 (0.92 to 1.00; p < 0.0001). CMR-estimated PVR reliably identified invasive PVR ≥3 Wood units (WU) with a high degree of accuracy, the area under the ROC curve was 0.94 (0.88 to 0.99; p < 0.0001).
  
  
  CONCLUSIONS
  CMR imaging can accurately estimate mean pulmonary artery pressure in patients with suspected pulmonary hypertension and calculate PVR by estimating all major pulmonary hemodynamic metrics measured at RHC.
authors.affiliation: Unit of Academic Radiology, University of Sheffield, Sheffield, England; National Institute of Health Research, Cardiovascular Biomedical Research Unit, Sheffield, England. Electronic address: a.j.swift@shef.ac.uk.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Swift
authors.affiliation: Unit of Academic Radiology, University of Sheffield, Sheffield, England.
authors.forename: Smitha
authors.initials: S
authors.lastname: Rajaram
authors.affiliation: Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.
authors.forename: Judith
authors.initials: J
authors.lastname: Hurdman
authors.affiliation: Radiology Department, Sheffield Teaching Hospitals Trust, Sheffield, England.
authors.forename: Catherine
authors.initials: C
authors.lastname: Hill
authors.affiliation: Radiology Department, Sheffield Teaching Hospitals Trust, Sheffield, England.
authors.forename: Christine
authors.initials: C
authors.lastname: Davies
authors.affiliation: Unit of Academic Radiology, University of Sheffield, Sheffield, England.
authors.forename: Tom W
authors.initials: TW
authors.lastname: Sproson
authors.affiliation: National Institute of Health Research, Cardiovascular Biomedical Research Unit, Sheffield, England; Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.
authors.forename: Allison C
authors.initials: AC
authors.lastname: Morton
authors.affiliation: Unit of Academic Radiology, University of Sheffield, Sheffield, England.
authors.forename: Dave
authors.initials: D
authors.lastname: Capener
authors.affiliation: National Institute of Health Research, Cardiovascular Biomedical Research Unit, Sheffield, England; Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.
authors.forename: Charlie
authors.initials: C
authors.lastname: Elliot
authors.affiliation: National Institute of Health Research, Cardiovascular Biomedical Research Unit, Sheffield, England; Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.
authors.forename: Robin
authors.initials: R
authors.lastname: Condliffe
authors.affiliation: Unit of Academic Radiology, University of Sheffield, Sheffield, England; Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.
authors.forename: Jim M
authors.initials: JM
authors.lastname: Wild
authors.affiliation: National Institute of Health Research, Cardiovascular Biomedical Research Unit, Sheffield, England; Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, England.
authors.forename: David G
authors.initials: DG
authors.lastname: Kiely
mesh_terms: D000368:Aged; D019540:Area Under Curve; D062186:Arterial Pressure; D006328:Cardiac Catheterization; D016009:Chi-Square Distribution; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology; D016014:Linear Models; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000503:physiopathology*; D011652:Pulmonary Circulation; D012372:ROC Curve; D012042:Registries; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014655:Vascular Resistance
keywords: BSA; CMR; CO; LA; LV; PCWP; PH; PVR; RHC; ROC; RV; SA; SSFP; VMI; body surface area; cardiac magnetic resonance; cardiac output; cardiovascular magnetic resonance imaging; left atrial; left ventricle/ventricular; mPAP; mean pulmonary arterial pressure; pulmonary artery pressure; pulmonary capillary wedge pressure; pulmonary hypertension; pulmonary vascular resistance; receiver-operating characteristic; right heart catheterization; right ventricular; short axis; steady-state free precession; ventricular mass index