Untreated IPAH has a poor prognosis. In the American prospective study the median survival was 2.8 years (1). Patients with PAH associated with connective tissue disease have a worse prognosis whereas those with congenital heart disease fare better.
Disease-targeted therapies for PAH have been shown to improve survival or prognostic indicators and there are studies demonstrating this for prostanoids, endothelin receptor antagonists, phosphodiesterase inhibitors and soluble guanylate cyclase stimulators. These are summarised in the 2015 guidelines.
Baseline prognostic indicators in PAH include functional class, exercise capacity, right ventricular function and NTproBNP. For more details, see the ESC guidelines on this link.
1. Rich S et al. Primary pulmonary hypertension. A national prospective study. Ann Intern Med 1987; 107:216-223..