Cardiopulmonary exercise testing in patients with pulmonary arterial hypertension: an evidence-based review.

BACKGROUND There is an increasing recognition of the potential value of cardiopulmonary exercise testing (CPX) in patients with pulmonary hypertension (PH). Key CPX characteristics in these patients include: (1) a diminished aerobic capacity; (2) an abnormally elevated minute ventilation-carbon dioxide production relationship; and (3) an abnormally diminished partial pressure of end-tidal carbon dioxide. Given the burgeoning number of original research investigations utilizing CPX in patients with PH, a summation of the presently available body of literature seems timely. METHODS A literature search was conducted in pubmed using "cardiopulmonary exercise testing" and "pulmonary arterial hypertension" as key phrases. Only studies conducting exercise testing with simultaneous ventilatory expired gas analysis in subjects with a confirmed diagnosis of pulmonary arterial hypertension were included. Twenty-three investigations were included in this review. Nineteen of the investigations assessed cohorts with resting pulmonary arterial hypertension as the sole diagnosis. Two investigations assessed subjects with chronic obstructive pulmonary disease and pulmonary arterial hypertension: one assessed subjects with pulmonary fibrosis and pulmonary arterial hypertension, and another included groups with exercise-induced pulmonary arterial hypertension and resting pulmonary arterial hypertension. RESULTS Collectively, these investigations indicate variables obtained from CPX: (1) reflect varying degrees of PH severity; (2) positively respond to several pharmacologic and surgical interventions; and (3) may provide prognostic value. CONCLUSIONS Currently, CPX is not widely utilized in patients with PH. Although more research is required in a number of areas, the present evidence-based review indicates this exercise testing technique may provide valuable information in the PH population.