title: Pulmonary surfactant protein B in the peripheral circulation and functional impairment in patients with chronic heart failure.
abstract: OBJECTIVE
  Surfactant protein B (SP-B) is a marker of damage to the alveolar-capillary barrier that could be useful for monitoring functional impairment in patients with chronic heart failure (HF).
  
  
  METHODS
  Dyspnea-limited cardiopulmonary exercise testing was carried out in 43 outpatients with chronic HF (age 51+/-10 years, 77% male, left ventricular ejection fraction [LVEF] 33+/-11%). Peripheral blood serum samples were obtained at rest and during the first minute of peak exercise. The presence and concentration of SP-B in the serum samples were determined by Western blot analysis.
  
  
  RESULTS
  At rest, SP-B was detected in 35 (82%) patients compared with only six (23%) healthy volunteers in a control group (n=26, age 51+/-10 years, 77% male). The median circulating SP-B level was higher in HF patients, at 174 [interquartile range, 70-283] vs. 77 [41-152] (P< .001) in the control group. In HF patients, the presence of circulating SP-B was associated with a lower LVEF (31.4+/-9.6% vs. 41.8+/-15%; P=.01). Multivariate analysis showed that the resting SP-B level correlated with a greater VE/VCO2 slope (beta=1.45; P=.02). The peak-exercise SP-B level correlated almost perfectly with the resting level (r=0.980; P< .001), but there was no significant increase with exercise (P=.164). Nor was there a correlation with any other exercise parameter.
  
  
  CONCLUSIONS
  In patients with chronic HF, the level of pulmonary surfactant protein B in the peripheral circulation is increased and is correlated with ventilatory inefficiency during exercise, as indicated by the VE/VCO2 slope.
authors.affiliation: Unidad de Insuficiencia Cardiaca, Servicio de Cardiología, Hospital Universitario Virgen de la Arrixaca, Departamento de Medicina Interna, Universidad de Murcia, Murcia, Spain. dapascual@servicam.com
authors.forename: Domingo A
authors.initials: DA
authors.lastname: Pascual-Figal
authors.forename: Jesús
authors.initials: J
authors.lastname: Sánchez-Más
authors.forename: Gonzalo
authors.initials: G
authors.lastname: de la Morena
authors.forename: Teresa
authors.initials: T
authors.lastname: Casas
authors.forename: Iris P
authors.initials: IP
authors.lastname: Garrido
authors.forename: Juan A
authors.initials: JA
authors.lastname: Ruipérez
authors.forename: Mariano
authors.initials: M
authors.lastname: Valdés
mesh_terms: D002908:Chronic Disease; D004417:Dyspnea / Q000209:etiology; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D037701:Pulmonary Surfactant-Associated Protein B / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D012044:Regression Analysis; D016277:Ventricular Function, Left
chemical_list: D037701:Pulmonary Surfactant-Associated Protein B