The noninvasive evaluation of exercise-induced changes in pulmonary artery pressure and pulmonary vascular resistance

Background: During exercise, pulmonary artery systolic pressure (PASP) may increase. The purpose of this study was to examine the responses of PASP and pulmonary vascular resistance by Doppler echocardiography during exercise in conditioned athletes and in patients with pulmonary disease. Methods: Fifteen participants in each group were evaluated using Doppler echocardiography at rest and during recumbent bicycle exercise. PASP was calculated using 4 times the tricuspid regurgitant velocity squared (TRV)(2) and a surrogate for pulmonary vascular resistance was calculated using the equation: pulmonary vascular resistance = TRV/ right ventricular outflow tract time-velocity integral. Results. During exercise, PASP increased in both groups with higher values achieved by patients with puhnonary conditions (54.8 vs 70.6 mm Hg, P =.009). At baseline the ratio TRV/right ventricular outflow tract time-velocity integral was 0.2 or less in both the athlete and pulmonary groups. During exercise, the ratio of TRV/right ventricular outflow tract time-velocity integral remained less than 0.2 in the athletes and increased more than 0.2 in the pulmonary group. Conclusion: Doppler echocardiography can be used to discriminate a flow- versus resistance-mediated mechanism for exercised-induced increase in PASP.