Detection of Exercise-Induced Pulmonary Arterial Hypertension by Cardiopulmonary Exercise Testing

Background: The pulmonary arterial pressure (PAP) response to exercise may provide a tool for the early detection of pulmonary arterial hypertension (PAH). Therefore, an accurate noninvasive method for evaluating exercise-induced PAH (EIPAH) is desirable. Hypothesis: We sought to examine if cardiopulmonary exercise testing (CPET) is able to indicate EIPAH. Methods: Fifty-three patients aged 67.1 +/- 1.7 years (37 female, 16 male) with borderline PAH (resting mean PAP 2124 mm Hg) performed CPET and right heart catheterization at rest and during handgrip testing. Results: When comparing patients with an exercise-induced mean PAP =35 mm Hg (group A, n = 24) and subjects with an exercise-induced mean PAP <35 mm Hg (group B, n = 29), group A had a significantly lower mean aerobic capacity (15.2 +/- 1.2 vs 19.7 +/- 1.2 mL/min/kg; P = 0.02), higher ventilatory equivalents for oxygen at the anaerobic threshold (34.3 +/- 1.5 vs 29.9 +/- 1.1; P = 0.02), a widening of the mean alveolar-arterial oxygen difference (37.8 +/- 3.0 vs 26.8 +/- 2.4 mm Hg; P = 0.007), an elevated mean functional dead space ventilation (29.5 +/- 2.7 vs 21.2 +/- 1.7%; P = 0.008), and a higher mean arterial to end-tidal carbon dioxide gradient at peak exercise (3.7 +/- 0.9 vs 0.4 +/- 0.8 mm Hg; P = 0.007). Conclusions: EIPAH is characterized by a decreased ventilatory efficiency due to ventilation to perfusion inequalities. CPET may be useful for the identification of EIPAH and serve to diagnose PAH at an early stage. Drs. Schwaiblmair, von Scheidt, and Berghaus conceived and designed the study. Drs. Schwaiblmair, Faul, and Berghaus acquired the study data. Dr. Schwaiblmair performed the statistical analysis and drafted the article. All authors participated in interpreting the data and revised the manuscript for important intellectual content. The authors have no funding, financial relationships, or conflicts of interest to disclose.