title: Value of exercise treadmill testing in the risk stratification of patients with pulmonary hypertension.
abstract: BACKGROUND
  The ability of the Naughton-Balke exercise treadmill test, an objective indicator of exercise capacity, to predict abnormal hemodynamics and mortality in pulmonary hypertension is unknown.
  
  
  RESULTS
  We performed a cohort study of 603 patients with pulmonary hypertension from 1982 to 2006, and studied the utility of exercise treadmill test as a predictor of abnormal hemodynamics and death. We used multivariable linear regression to determine whether exercise capacity, measured in metabolic equivalents, was associated with abnormal hemodynamics, and we used a Cox proportional hazards model to determine whether decreased exercise capacity predicted death. Mean age was 50+/-15 years, 76% were women, 63% had World Health Organization category I pulmonary arterial hypertension, and 23% were World Health Organization functional classes I and II. Mean exercise capacity was 3.7+/-2.2 metabolic equivalents. Decreased exercise capacity was independently associated with elevated right atrial and mean pulmonary artery pressure, decreased cardiac index, and increased pulmonary vascular resistance. During median follow-up of 4.6 years, 36% of the patients died. Decreased exercise capacity was associated with mortality (multivariable hazard ratio, 1.18; 95% CI, 1.01 to 1.37 for each 1-metabolic equivalent decrease in exercise capacity; P=0.031; P=0.052 after adjusting for invasive hemodynamic variables). Decreased exercise capacity also predicted mortality in functional classes I-II patients, 24% of whom died (hazard ratio, 1.53; 95% CI, 1.04 to 2.26 for each 1-metabolic equivalent decrease in exercise capacity; P=0.032), although this association did not persist after adjusting for invasive hemodynamic variables (P=0.63).
  
  
  CONCLUSIONS
  Reduced exercise capacity on exercise treadmill test is associated with worse hemodynamics and is a predictor of mortality in patients with pulmonary hypertension.
authors.affiliation: Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Sanjiv J
authors.initials: SJ
authors.lastname: Shah
authors.forename: Thenappan
authors.initials: T
authors.lastname: Thenappan
authors.forename: Stuart
authors.initials: S
authors.lastname: Rich
authors.forename: James
authors.initials: J
authors.lastname: Sur
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Archer
authors.forename: Mardi
authors.initials: M
authors.lastname: Gomberg-Maitland
mesh_terms: D000328:Adult; D000368:Aged; D005080:Exercise Test; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000401:mortality*; D008297:Male; D055686:Metabolic Equivalent; D008875:Middle Aged; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index