Fig. 2

Transplant-free survival. (a) Kaplan–Meier plot of cumulative transplant-free survival and (b) Cox regression estimate of transplant-free survival after correction for possible confounders (New York Heart Association functional class, 6-minute-walk distance, and cardiac output). Patients were treated sequentially with iloprost and sildenafil (either iloprost followed by addition of sildenafil [iloprost/sildenafil] or sildenafil followed by addition of iloprost [sildenafil/iloprost]), or with upfront combination therapy (iloprost + sildenafil)