Cardiopulmonary exercise testing in exercise induced pulmonary hypertension

Objective To determine the accuracy of cardiopulmonary exercise-testing (CPET) in detecting exercise-induced pulmonary hypertension. Background CPET plays a key role in the investigation of exertional breathlessness. Exercise-induced pulmonary hypertension has been recently demonstrated to be a cause of exertional dyspnea. However, the features of CPET associated with the condition are still unknown. Methods We prospectively studied CPET and exercise echocardiography characteristics in 39 patients complaining of exertional breathlessness. Patients could be divided into 3 groups as follows: 1) control subjects having normal pulmonary arterial pressure at rest [pulmonary arterial systolic pressure < 35 mmHg] and at peak exercise [pulmonary arterial systolic pressure < 45 mmHg]; 2) patients having exercise-induced PH; 3) patients having resting PH. Results from CPET have been analyzed within each group. Results Patients developing exercise-induced PH revealed an increased V-D/V-T ratio and CO2 gradient (P[a-ET]CO2) at peak exercise compared to controls (V-D/V-T at 0.38 +/- 0.1 vs 0.29 +/- 0.11 and P[a-ET]CO2 at 4,6 +/- 3,1 vs 1 +/- 3,8 mmHg). V-D/V-T and P[a-ET]CO2 were increased in patients with resting PH. A V-D/V-T ratio at peak exercise higher than 0.34 was 72.7% sensitive and 71% specific in predicting exercise-induced PH. Positive and negative predictive values were 72.7% and 70.1% respectively. Conclusion Patients with exercise-induced PH did not decrease or may increase dead space during exercise. Therefore CPET may be a useful tool in selecting patients who need to undergo further exercise haemodynamic investigations.