Exercise pathophysiology in patients with primary pulmonary hypertension

Background-Patients with primary pulmonary hypertension (PPH) have a pulmon ary vasculopathy that leads to exercise intolerance due to dyspnea and fati gue. To better understand the basis of the exercise limitation in patients with PPH, cardiopulmonary exercise testing (CPET) with gas exchange measure ments, New York Heart Association (NYHA) symptom class, and resting pulmona ry hemodynamics were studied. Methods and Results-We retrospectively evaluated 53 PPH patients who had ri ght heart catheterization and cycle ergometer CPET studies to maximum toler ance as part of their clinical workups. No adverse events occurred during C PET. Reductions in peak O-2 uptake (VO2), anaerobic threshold, peak O-2 pul se, rate of increase in VO2, and ventilatory efficiency were consistently f ound. NYHA class correlated well with the above parameters of aerobic funct ion and ventilatory efficiency but less well with resting pulmonary hemodyn amics. Conclusions-Patients with PPH can safely undergo noninvasive cycle ergomete r CPET to their maximal tolerance. The CPET abnormalities were consistent a nd characteristic and correlated well with NYHA class.