title: Comparison of change in end tidal carbon dioxide after three minutes of step exercise between systemic sclerosis patients with and without pulmonary hypertension.
abstract: Pulmonary hypertension (PH) is an important cause of morbidity and mortality in patients with SSc. The submaximal heart and pulmonary evaluation (step test) is a non-invasive, submaximal stress test that could be used to identify SSc patients with PH. Our aims were to determine whether change in end tidal carbon dioxide ([Formula: see text]) from rest to end-exercise, and the minute ventilation to carbon dioxide production ratio ([Formula: see text]), both as measured by the step test, differ between SSc patients with and without PH. We also examined differences in validated self-report questionnaires and potential PH biomarkers between SSc patients with and without PH.
  
  
  
  We performed a cross-sectional study of 27 patients with limited or dcSSc who underwent a right heart catheterization within 24 months prior to study entry. The study visit consisted of questionnaire completion; history; physical examination; step test performance; and phlebotomy. [Formula: see text], [Formula: see text], self-report data and biomarkers were compared between patients with and without PH.
  
  
  
  SSc patients with PH had a statistically significantly lower median (interquartile range) [Formula: see text] than SSc patients without PH [-2.1 (-5.1 to 0.7) vs 1.2 (-0.7 to 5.4) mmHg, P = 0.035], and a statistically significantly higher median (interquartile range) [Formula: see text] [53.4 (39-64.1) vs 36.4 (31.9-41.1), P = 0.035]. There were no statistically significant differences in self-report data or biomarkers between groups.
  
  
  
  [Formula: see text] and [Formula: see text] as measured by the step test are statistically significantly different between SSc patients with and without PH. [Formula: see text] and [Formula: see text] may be useful screening tools for PH in the SSc population.
authors.affiliation: Division of Rheumatology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York-Presbyterian Hospital ejb2153@columbia.edu.
authors.forename: Elana J
authors.initials: EJ
authors.lastname: Bernstein
authors.affiliation: Division of Rheumatology, Department of Medicine, Hospital for Special Surgery.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Gordon
authors.affiliation: Division of Rheumatology, Department of Medicine, Hospital for Special Surgery.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Spiera
authors.affiliation: Division of Rheumatology, Department of Medicine, Hospital for Special Surgery.
authors.forename: Wei-Ti
authors.initials: WT
authors.lastname: Huang
authors.affiliation: Division of Cardiology, Department of Medicine, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Horn
authors.affiliation: Division of Rheumatology, Department of Medicine, Hospital for Special Surgery.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Mandl
mesh_terms: D000368:Aged; D001944:Breath Tests; D002245:Carbon Dioxide / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics; D015850:Interleukin-6 / Q000378:metabolism; D008168:Lung / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045743:Scleroderma, Diffuse / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D045745:Scleroderma, Limited / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D012595:Scleroderma, Systemic / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C508600:IL6 protein, human; D015850:Interleukin-6; D010446:Peptide Fragments; D012333:RNA, Messenger; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D002245:Carbon Dioxide
keywords: end tidal carbon dioxide; pulmonary hypertension; right heart catheterization; scleroderma; submaximal exercise testing; systemic sclerosis