title: Effects of exercise and vasodilators on cerebral tissue oxygenation in pulmonary hypertension.
abstract: BACKGROUND
  Arterial and thromboembolic pulmonary hypertension (PH) lead to arterial hypoxaemia.
  
  
  OBJECTIVE
  To investigate whether cerebral tissue oxygenation (CTO) in patients with PH is reduced and whether this is associated with reduced exercise tolerance.
  
  
  METHODS
  16 patients with PH (mean pulmonary arterial pressure ≥25 mmHg, 14 arterial, 2 chronic thromboembolic) and 15 controls underwent right heart catheterisation with monitoring of CTO at rest, during maximal bicycle exercise and during inhalation of oxygen and NO. The 6 min walk distance (6MWD) was measured.
  
  
  RESULTS
  Median CTO in PH-patients at rest was 62 % (quartiles 53; 71), during exercise 60 % (53; 65); corresponding values in controls were 65 % (73; 73) (P = NS) and 68 % (66; 70) (p = .013 vs. PH). Inhalation of NO and oxygen improved CTO in PH. In multivariate regression analysis CTO at maximal exercise predicted the work load achieved when controlled for age, pulmonary vascular resistance and mixed venous oxygen saturation (R (2) = .419, p < .000); in addition, the 6MWD was predicted by CTO (adjusted R (2) = .511, p < .000).
  
  
  CONCLUSIONS
  In PH-patients but not in controls CTO decreased during exercise. Since CTO was an independent predictor of the work load achieved and the 6MWD cerebral hypoxia may contribute to exercise limitation in PH. Clinicaltrials.gov: NCT01463514.
authors.affiliation: Clinic of Pulmonology, University Hospital of Zurich, Rämistrasse 100, 8091, Zurich, Switzerland, severine.mueller-mottet@usz.ch.
authors.forename: Séverine
authors.initials: S
authors.lastname: Müller-Mottet
authors.forename: Florian F
authors.initials: FF
authors.lastname: Hildenbrand
authors.forename: Stephan
authors.initials: S
authors.lastname: Keusch
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Hasler
authors.forename: Marco
authors.initials: M
authors.lastname: Maggiorini
authors.forename: Rudolf
authors.initials: R
authors.lastname: Speich
authors.forename: Konrad E
authors.initials: KE
authors.lastname: Bloch
authors.forename: Silvia
authors.initials: S
authors.lastname: Ulrich
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D001921:Brain / Q000098:blood supply* / Q000187:drug effects* / Q000378:metabolism; D006328:Cardiac Catheterization; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects*; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009569:Nitric Oxide / Q000008:administration & dosage*; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000187:drug effects*; D010102:Oxygen Inhalation Therapy; D011237:Predictive Value of Tests; D019265:Spectroscopy, Near-Infrared; D013557:Switzerland; D013997:Time Factors; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000008:administration & dosage*
chemical_list: D000959:Antihypertensive Agents; D014665:Vasodilator Agents; D009569:Nitric Oxide; D010100:Oxygen