Exercise-Induced Pulmonary Arterial Wedge Pressure Elevation in Subjects Who Had SOB Unknown Reason

Background: Exercise-induced elevation of pulmonary arterial wedge pressure (PAWP) may show preclinical or exercise-induced left ventricular diastolic dysfunction. The aim of this study was to compare the CPX parameters, that can be available non-invasively, between elevation and normal exercise PAWP in subjects with SOB unknown reason. Methods: Fourteen subjects who had SOB unknown reason (55 ± 14 y/o, 13 female, mean pulmonary arterial pressure (PAP) 16 mmHg, PAWP 8 mmHg) with normal PAWP (under 15 mmHg) at rest underwent symptom-limited exercise test using supine cycle ergometer with right heart catheter. Exercise-induced elevation in PAWP of more than 20 mmHg was defined as elevation group. Results: Among 14 subjects, exercise-induced PAWP elevation was shown in 5 subjects. In the elevation group, age was tend to be older, δPAWP (after legs raise—rest) was higher (4.2 ± 4.6 vs 1.7 ± 4.1 mmHg) after legs raise approximately 30 degrees for cycle ergometer exercise. In the CPX parameters, peak oxygen consumption was tend to be lower (14.0 ± 8.1 vs 18.9 ± 7.7 mL⋅min⁻¹⋅kg⁻¹, and VE vs VCO2 slope (44.3 ± 22.9 vs 32.1 ± 7.6) was tend to be higher compared with in the non-elevation group. Conclusion: Exercise-induced PAWP elevation is often seen in subjects who had SOB unknown reason, even if normal PAWP pressure at rest. Exercise intolerance and higher ventilator efficiency are suspicious non-invasive parameters for the exercise-induced PAWP. Further examinations are needed.