title: Effects of pulmonary vasodilator therapy on ventilatory efficiency during exercise in adults with Eisenmenger syndrome.
abstract: OBJECTIVE
  Eisenmenger syndrome, characterized by systemic-level pulmonary arterial resistance with resultant right-to-left shunt, is associated with low exercise capacity and hyperpnea at rest and exercise. Because ventilatory requirements are augmented by right-to-left shunting, we hypothesized that if pulmonary vasodilator treatment improved pulmonary perfusion in this condition, this would also improve ventilatory efficiency during exercise.
  
  
  METHODS
  To investigate this, data from incremental cardiopulmonary exercise tests performed by Eisenmenger patients before and after beginning therapy with pulmonary hypertension medications were retrospectively analyzed. Setting.  Ahmanson/University of California, Los Angeles Adult Congenital Heart Disease Center.
  
  
  METHODS
  Ten adults with Eisenmenger syndrome treated with either bosentan or sildenafil.
  
  
  METHODS
  The primary analysis was comparison, before and after treatment, of the efficiency of exercise ventilation as reflected in the ratio of ventilation (.V(E)) to carbon dioxide output (.VCO₂) measured at the anaerobic threshold (AT), the slope of .V(E)/.VCO₂ during incremental exercise, and end tidal partial pressure of CO₂ (PETCO₂) at the AT. Secondary measures included peak oxygen uptake (.VO₂) and AT.
  
  
  RESULTS
  Following treatment there were significant reductions in the slope .V(E)/.VCO₂ (59.5 ± 12.9 vs. 50.0 ± 7.2, P= .003), and significant decrease in .V(E)/.VCO₂ ratio (56.9 ± 6.2 vs. 50.2 ± 5.9, P= .00004) and increase in PETCO₂ (21.12 ± 2.43 vs. 23.9 ± 2.62 torr, P= .0092) measured at the AT. Increases in peak .VO₂ (0.73 ± 0.25 vs. 0.78 ± 0.32 L/min, P= .333) and AT (0.61 ± 0.20 vs. 0.68 ± 0.25 L/min, P= .154) were not significant.
  
  
  CONCLUSIONS
  These findings are consistent with reduction in right-to-left shunt due to improved pulmonary blood flow, though attenuation of ventilatory drive is not excluded. Treatment of adult Eisenmenger patients with pulmonary the pulmonary vasodilators bosentan or sildenafil leads to improvement in parameters of ventilatory efficiency during exercise.
authors.affiliation: Kaiser Permanente Medical Center, Downey, CA, USA.
authors.forename: Showshan
authors.initials: S
authors.lastname: Yang-Ting
authors.forename: Jamil
authors.initials: J
authors.lastname: Aboulhosn
authors.forename: Xing-Guo
authors.initials: XG
authors.lastname: Sun
authors.forename: John S
authors.initials: JS
authors.lastname: Child
authors.forename: Kathy E
authors.initials: KE
authors.lastname: Sietsema
mesh_terms: D000328:Adult; D000959:Antihypertensive Agents / Q000627:therapeutic use; D000077300:Bosentan; D004541:Eisenmenger Complex / Q000188:drug therapy* / Q000503:physiopathology; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects*; D005260:Female; D006801:Humans; D015141:Los Angeles; D008168:Lung / Q000098:blood supply / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010879:Piperazines / Q000627:therapeutic use*; D011651:Pulmonary Artery / Q000187:drug effects* / Q000503:physiopathology; D011652:Pulmonary Circulation / Q000187:drug effects; D012123:Pulmonary Ventilation / Q000187:drug effects*; D011687:Purines / Q000627:therapeutic use; D012189:Retrospective Studies; D000068677:Sildenafil Citrate; D013449:Sulfonamides / Q000627:therapeutic use*; D013450:Sulfones / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D000959:Antihypertensive Agents; D010879:Piperazines; D011687:Purines; D013449:Sulfonamides; D013450:Sulfones; D014665:Vasodilator Agents; D000068677:Sildenafil Citrate; D000077300:Bosentan