Impact of targeted pulmonary arterial hypertension therapies in severe pulmonary hypertension in chronic lung diseases

Research questions Patients with severe pulmonary hypertension associated with chronic lung disease have a poor prognosis. Targeted pulmonary arterial hypertension therapies might improve exercise capacity and outcome, but there are no guidelines on treatments which are not recommended because of an unproven benefit, with discordant results from few studies in this context. The aim of our study was to evaluate targeted pulmonary arterial hypertension therapies for severe group 3 pulmonary hypertension patients. Study design and methods We conducted an observational retrospective monocentre study on patients with severe group 3 pulmonary hypertension diagnosed on right heart catheterisation treated with targeted therapies. Primary outcome was an improvement of the distance on 6-min walk test of.30 m. Secondary end-points included changes in haemodynamics ( pulmonary vascular resistance (PVR) and mean pulmonary arterial pressure (mPAP)) and identification of potential predictive factors of therapeutic response. Results 139 patients were enrolled. Most patients had monotherapy with phosphodiesterase 5 inhibitors (n=128; 92%). Mean change in 6-min walk distance was +1.5 m after treatment (p=0.59). Forced expiratory volume in 1 s and forced vital capacity were not predictive factors for response. We found a significant improvement of PVR and mPAP of -1.0 Wood Units ( p<0.001) and -4 mmHg ( p<0.001), respectively, under treatment. 18% of patients had to withdraw treatment for intolerance. Treatment duration <3 months was associated with poor survival (hazard ratio 2.75, p=0.0005). Conclusion Oral targeted pulmonary arterial hypertension therapies do not improve exercise capacity in patients with severe pulmonary hypertension associated with chronic lung disease, but could improve haemodynamic parameters.