title: Reduction of maximal oxygen uptake in sarcoidosis: relationship with disease severity.
abstract: BACKGROUND
  Patients with sarcoidosis frequently exhibit exertional dyspnea. Although the functional limitation might be related to ventilatory problems, some patients exhibited exertional dyspnea without significant abnormalities of pulmonary function tests (PFT). Therefore, the mechanisms responsible for exercise intolerance remain unclear.
  
  
  OBJECTIVE
  The aim of this retrospective study was to determine the mechanisms responsible for exercise intolerance.
  
  
  METHODS
  Cardiopulmonary exercise testing (CPET) was performed in 157 dyspneic sarcoid patients (stage I: 29; stage II-III: 95; stage IV: 33) and VO2 peak was correlated with radiological stage and resting PFT.
  
  
  RESULTS
  VO2 peak was decreased in 73% patients, did not differ according to radiological stage and was correlated with VC, FVC, FEV1, TLC and DLCO. FVC was the major significant predictor of VO2 peak explaining 17% of VO2 variation. Among CPET variables, peak heart rate and VE/VO2 at ventilatory threshold explained 22% of VO2 alteration in stage I and stage II-III, and 9% in stage IV. In stage IV, V(D)/V(T) peak explained 41% of VO2 alteration.
  
  
  CONCLUSIONS
  In conclusion, in the lower stages circulatory impairment and impaired heart rate response to exercise are involved in the exercise capacity limitation, whereas in stage IV the ventilatory and gas exchange impairment may be more important. CPET must be performed to accurately characterize the mechanisms responsible for exercise limitation and help the clinician in the management of the disease.
authors.affiliation: Clinique des Maladies Respiratoires, Centre de Compétence des Maladies Pulmonaires Rares, Hôpital Calmette, CHRU Lille, Lille, France. benoit.wallaert @ chru-lille.fr
authors.forename: Benoit
authors.initials: B
authors.lastname: Wallaert
authors.forename: Christelle
authors.initials: C
authors.lastname: Talleu
authors.forename: Lidwine
authors.initials: L
authors.lastname: Wemeau-Stervinou
authors.forename: Alain
authors.initials: A
authors.lastname: Duhamel
authors.forename: Sophie
authors.initials: S
authors.lastname: Robin
authors.forename: Bernard
authors.initials: B
authors.lastname: Aguilaniu
mesh_terms: D000328:Adult; D000368:Aged; D015308:Anaerobic Threshold; D004417:Dyspnea / Q000378:metabolism* / Q000503:physiopathology; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D011237:Predictive Value of Tests; D011659:Pulmonary Gas Exchange; D012146:Rest; D012189:Retrospective Studies; D012507:Sarcoidosis / Q000378:metabolism* / Q000503:physiopathology; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D010100:Oxygen