title: Right ventricular load at exercise is a cause of persistent exercise limitation in patients with normal resting pulmonary vascular resistance after pulmonary endarterectomy.
abstract: BACKGROUND
  Pulmonary endarterectomy (PEA) provides a potential cure for patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, successfully operated patients can continue to suffer from a limitation of exercise capacity, despite normalization of pulmonary vascular resistance (PVR). The purpose of the present study was to explore the cardiopulmonary exercise test (CPET) profile and the pulmonary hemodynamic response to exercise in these patients.
  
  
  METHODS
  Thirteen successfully operated patients with CTEPH and persistent dyspnea and control subjects underwent a CPET and a right-sided heart catheterization at rest and during exercise.
  
  
  RESULTS
  The CPET profile of the patients was characterized by mild hyperventilation and decreased peak oxygen uptake (VO2). While there were no differences in resting hemodynamics between patients and control subjects, PVR was higher in the patients after 10 min of exercise (111 ± 46 dynes/s/cm(5) vs 71 ± 42 dynes/s/cm(5), P = .04), and pulmonary arterial compliance (Ca) was lower (5.5 ± 2.3 mL/mm Hg vs 8.1 ± 3.5 mL/mm Hg, P = .048). Ca under exercise correlated with peak VO2 in the patients (R(2) = 0.825, P = .022).
  
  
  CONCLUSIONS
  After successful PEA, patients with persistent exertional dyspnea display an abnormal pulmonary hemodynamic response to exercise, characterized by increased PVR and decreased Ca. Decreased Ca under exercise is a strong predictor of limited exercise capacity in these patients.
authors.affiliation: Department of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Diana
authors.initials: D
authors.lastname: Bonderman
authors.forename: Amadea M
authors.initials: AM
authors.lastname: Martischnig
authors.forename: Karin
authors.initials: K
authors.lastname: Vonbank
authors.forename: Mariam
authors.initials: M
authors.lastname: Nikfardjam
authors.forename: Brigitte
authors.initials: B
authors.lastname: Meyer
authors.forename: Gottfried
authors.initials: G
authors.lastname: Heinz
authors.forename: Walter
authors.initials: W
authors.lastname: Klepetko
authors.forename: Robert
authors.initials: R
authors.lastname: Naeije
authors.forename: Irene M
authors.initials: IM
authors.lastname: Lang
mesh_terms: D006328:Cardiac Catheterization; D004691:Endarterectomy; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011651:Pulmonary Artery / Q000503:physiopathology* / Q000601:surgery; D011655:Pulmonary Embolism / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D011669:Pulmonary Wedge Pressure; D012146:Rest; D012189:Retrospective Studies; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000502:physiology*; D016278:Ventricular Function, Right / Q000502:physiology*