Is it possible to predict pulmonary arterial hypertension from an exercise test?

In patients with chronic lung disease, the response to exercise can be impaired by ventilatory and/or circulatory disturbances. The response to a standard exercise varies according to the load in relation to the maximum load the subject can tolerate. Thus it seems more suitable to study the maximum tolerated, i.e. maximum workload expressed as VO2 max. We compared the results of VO2 max and pulmonary haemodynamic variables in 43 patients with chronic bronchitis. VO2 max ranged from 0.720 to 3.010 l/min. The relation between VO2 max and pulmonary artery pressure at rest or its increase with low level exercise was very poor, but there was a trend towards an increase in pulmonary vascular resistance in patients with low VO2 max, although a number of patients with low VO2 max had normal pulmonary vascular resistance. The ratio between heart rate at maximum workload and maximum heart rate according to age (heart rate obs/pred) was above 95% in the patients with pulmonary vascular resistance above 250 dyn.s. cm-5; it varied widely in the patients with normal or slightly elevated pulmonary vascular resistance. When VO2 max was below normal, and heart rate obs/pred low, it is probable that the decrease in VO2 max was due to ventilation impairment, or to a lack of cooperation. Oxygen pulse at VO2 max was also reduced in patients with high pulmonary vascular resistance, but a large range of values was observed in the rest of the patients. A high oxygen pulse at VO2 max however allows to rule out severe pulmonary artery hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)