title: Clinically significant change in stroke volume in pulmonary hypertension.
abstract: BACKGROUND
  Stroke volume is probably the best hemodynamic parameter because it reflects therapeutic changes and contains prognostic information in pulmonary hypertension (PH). Stroke volume directly reflects right ventricular function in response to its load, without the correction of compensatory increased heart rate as is the case for cardiac output. For this reason, stroke volume, which can be measured noninvasively, is an important hemodynamic parameter to monitor during treatment. However, the extent of change in stroke volume that constitutes a clinically significant change is unknown. The aim of this study was to determine the minimal important difference (MID) in stroke volume in PH.
  
  
  METHODS
  One hundred eleven patients were evaluated at baseline and after 1 year of follow-up with a 6-min walk test (6MWT) and cardiac MRI. Using the anchor-based method with 6MWT as the anchor, and the distribution-based method, the MID of stroke volume change could be determined.
  
  
  RESULTS
  After 1 year of treatment, there was, on average, a significant increase in stroke volume and 6MWT. The change in stroke volume was related to the change in 6MWT. Using the anchor-based method, an MID of 10 mL in stroke volume was calculated. The distribution-based method resulted in an MID of 8 to 12 mL.
  
  
  CONCLUSIONS
  Both methods showed that a 10-mL change in stroke volume during follow-up should be considered as clinically relevant. This value can be used to interpret changes in stroke volume during clinical follow-up in PH.
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Serge A
authors.initials: SA
authors.lastname: van Wolferen
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Marielle C
authors.initials: MC
authors.lastname: van de Veerdonk
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: Mauritz
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Wouter
authors.initials: W
authors.lastname: Jacobs
authors.affiliation: Department of Physics and Medical Technology, Institute for Cardiovascular Research ICaR-VU, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: J Tim
authors.initials: JT
authors.lastname: Marcus
authors.affiliation: Department of Cardiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Koen M J
authors.initials: KMJ
authors.lastname: Marques
authors.affiliation: Department of Cardiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jean G F
authors.initials: JGF
authors.lastname: Bronzwaer
authors.affiliation: Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Martijn W
authors.initials: MW
authors.lastname: Heymans
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Anco
authors.initials: A
authors.lastname: Boonstra
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Pieter E
authors.initials: PE
authors.lastname: Postmus
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Nico
authors.initials: N
authors.lastname: Westerhof
authors.affiliation: Department of Pulmonary Disease, VU University Medical Center, Amsterdam, The Netherlands. Electronic address: a.vonk@vumc.nl.
authors.forename: Anton
authors.initials: A
authors.lastname: Vonk Noordegraaf
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013318:Stroke Volume