title: Exercise-induced pulmonary hypertension associated with systemic sclerosis: four distinct entities.
abstract: OBJECTIVE
  Exercise-induced pulmonary hypertension (PH) may represent an early but clinically relevant phase in the spectrum of pulmonary vascular disease. There are limited data on the prevalence of exercise-induced PH determined by right heart catheterization in scleroderma spectrum disorders. We undertook this study to describe the hemodynamic response to exercise in a homogeneous population of patients with scleroderma spectrum disorders at risk of developing pulmonary vascular disease.
  
  
  METHODS
  Patients with normal resting hemodynamics underwent supine lower extremity exercise testing. A classification and regression tree (CART) analysis was used to assess combinations of variables collected during resting right heart catheterization that best predicted abnormal exercise physiology, applicable to each individual subject.
  
  
  RESULTS
  Fifty-seven patients who had normal resting hemodynamics underwent subsequent exercise right heart catheterization. Four distinct hemodynamic groups were identified during exercise: a normal group, an exercise-induced pulmonary venous hypertension (ePVH) group, an exercise out of proportion PH (eoPH) group, and an exercise-induced PH (ePH) group. The eoPH and ePVH groups had higher pulmonary capillary wedge pressure (PCWP) than the ePH group (P < 0.05). The normal and ePH groups had exercise PCWP ≤18 mm Hg, which was lower than that in the ePVH and eoPH groups (P < 0.05). During submaximal exercise, the transpulmonary gradient and pulmonary vascular resistance (PVR) were elevated in the ePH and eoPH groups as compared with the normal and ePVH groups (P < 0.05). CART analysis suggested that resting mean pulmonary artery pressure (mPAP) ≥14 mm Hg and PVR ≥160 dynes/seconds/cm(-5) were associated with eoPH and ePH (positive predictive value 89% for mPAP 14-20 mm Hg and 100% for mPAP >20 mm Hg).
  
  
  CONCLUSIONS
  We characterized the exercise hemodynamic response in at-risk patients with scleroderma spectrum disorders who did not have resting PH. Four distinct hemodynamic groups were identified during exercise. These groups may have potentially different prognoses and treatment options.
authors: David Geffen School of Medicine at University of California, Los Angeles, CA 90095-1690, USA. rasaggar@mednet.ucla.edu
authors: Rajeev
authors: R
authors: Saggar
authors: Dinesh
authors: D
authors: Khanna
authors: Daniel E
authors: DE
authors: Furst
authors: Shelley
authors: S
authors: Shapiro
authors: Paul
authors: P
authors: Maranian
authors: John A
authors: JA
authors: Belperio
authors: Neeraj
authors: N
authors: Chauhan
authors: Philip
authors: P
authors: Clements
authors: Alan
authors: A
authors: Gorn
authors: S Sam
authors: SS
authors: Weigt
authors: David
authors: D
authors: Ross
authors: Joseph P
authors: JP
authors: Lynch
authors: Rajan
authors: R
authors: Saggar
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D006328:Cardiac Catheterization; D015331:Cohort Studies; D003663:Decision Trees; D015444:Exercise; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000145:classification* / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012595:Scleroderma, Systemic / Q000150:complications* / Q000503:physiopathology*; D014797:Vital Capacity / Q000502:physiology