title: Non-invasive stroke volume assessment in patients with pulmonary arterial hypertension: left-sided data mandatory.
abstract: BACKGROUND
  Cardiovascular magnetic resonance (CMR) is an emerging modality in the diagnosis and follow-up of patients with pulmonary arterial hypertension (PAH). Derivation of stroke volume (SV) from the pulmonary flow curves is considered as a standard in this respect. Our aim was to investigate the accuracy of pulmonary artery (PA) flow for measuring SV.
  
  
  METHODS
  Thirty-four PAH patients underwent both CMR and right-sided heart catheterisation. CMR-derived SV was measured by PA flow, left (LV) and right ventricular (RV) volumes, and, in a subset of nine patients also by aortic flow. These SV values were compared to the SV obtained by invasive Fick method.
  
  
  RESULTS
  For SV by PA flow versus Fick, r = 0.71, mean difference was -4.2 ml with limits of agreement 26.8 and -18.3 ml. For SV by LV volumes versus Fick, r = 0.95, mean difference was -0.8 ml with limits of agreement of 8.7 and -10.4 ml. For SV by RV volumes versus Fick, r = 0.73, mean difference -0.75 ml with limits of agreement 21.8 and -23.3 ml. In the subset of nine patients, SV by aorta flow versus Fick yielded r = 0.95, while in this subset SV by pulmonary flow versus Fick yielded r = 0.76. For all regression analyses, p < 0.0001.
  
  
  CONCLUSIONS
  In conclusion, SV from PA flow has limited accuracy in PAH patients. LV volumes and aorta flow are to be preferred for the measurement of SV.
authors.affiliation: Department of Pulmonary Diseases, Institute for Cardiovascular Research ICaR-VU, VU University Medical Center, Amsterdam, The Netherlands. gj.mauritz@vumc.nl
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: Mauritz
authors.forename: J Tim
authors.initials: JT
authors.lastname: Marcus
authors.forename: Anco
authors.initials: A
authors.lastname: Boonstra
authors.forename: Pieter E
authors.initials: PE
authors.lastname: Postmus
authors.forename: Nico
authors.initials: N
authors.lastname: Westerhof
authors.forename: Anton
authors.initials: A
authors.lastname: Vonk-Noordegraaf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000503:physiopathology; D001783:Blood Flow Velocity; D006328:Cardiac Catheterization; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000503:physiopathology*; D011652:Pulmonary Circulation; D015203:Reproducibility of Results; D013318:Stroke Volume; D055815:Young Adult