Prognostic value of exercise pulmonary haemodynamics in pulmonary arterial hypertension

The aim of the study was to investigate the prognostic value of right heart catheterisation variables measured during exercise. 55 incident patients with idiopathic, familial or anorexigen-associated pulmonary arterial hypertension (PAH) underwent right heart catheterisation at rest and during exercise and 6-min walk testing before PAH treatment initiation. Patients were treated according to recommendations within the next 2 weeks. Right heart catheterisation was repeated 3-5 months into the PAH treatment in 20 patients. Exercise cardiac index decreased gradually as New York Heart Association (NYHA) functional class increased whereas cardiac index at rest was not significantly different across NYHA groups. Baseline 6-min walk distance correlated significantly with exercise and change in cardiac index from rest to exercise (r=0.414 and r=0.481, respectively; p<0.01). Change in 6-min walk distance from baseline to 3-5 months under PAH treatment was highly correlated with change in exercise cardiac index (r=0.746, p<0.001). The most significant baseline covariates associated with survival were change in systolic pulmonary artery pressure from rest to exercise and exercise cardiac index (hazard ratio 0.56 (95% CI 0.37-0.86) and 0.14 (95% CI 0.05-0.43), respectively). Change in pulmonary haemodynamics during exercise is an important tool for assessing disease severity and may help devise optimal treat-to-target strategies.