Exercise hemodynamic findings in patients with exertional dyspnea

To determine whether upright bicycle exercise could provide useful information about disabling exertional dyspnea in the absence of severe abnormalities (as shown by traditional testing methods), we evaluated 13 such patients. There were 3 men and 10 women with a mean age of 49+/-15 (SD) years. We used pulmonary artery catheterization at rest and during upright bicycle exercise to evaluate these patients. All patients had normal left ventricular function except for 1, who had an ejection fraction of 45%. The mean duration to peak exercise was 9+/-6 minutes. Normal systolic pulmonary artery pressure was defined as 25+/-5 mmHg. Four patients had normal systolic pulmonary pressure, and 9 exhibited pulmonary hypertension with exercise. In those 9, the mean mixed pulmonary venous oxygen saturation at rest was 61%+/-9% and fell to 32%+/-9% at peak exercise. Six of the 9 patients also had some degree of resting pulmonary hypertension that worsened with exercise: their mean pulmonary artery systolic pressure at rest was 47+/-14 mmHg and rose to 75+/-25 mmHg at peak exertion (P = 0.01). The other 3 patients showed no pulmonary hypertension at rest; their mean pulmonary artery systolic pressure was 27+/-6 mmHg. However, this level rose to 53+/-4 mmHg at peak exertion (P = 0.04). In this pilot study of patients with dyspnea, 9 of 13 (69%) displayed marked pulmonary hypertension with exercise. The resting hemodynamic levels were normal in 3 (33%) of those with exercise pulmonary hypertension. We conclude that hemodynamic data from bicycle exercise tests can provide additional information regarding the mechanisms of exertional dyspnea.