Despite recent advances in the treatment of Primary Pulmonary Hypertension (PPH), lung transplantation remains a viable alternative when medical therapy fails. Unfortunately, short-term mortality after lung transplantation is the highest among all diagnostic groups. Identification of pre-transplant characteristics that would place recipients at high risk of death would be extremely valuable. We reviewed the United Network for Organ Sharing database to explore risk factors for post-transplant mortality among recipients with PPH. Between 1998 and 2007, 461 PPH patients underwent lung or heart/lung transplantation. The 1 and 3 yr survival of the entire cohort was 76% and 62%, respectively. Pulmonary hemodynamic data was available on 291 subjects. Mean age was 40 ± 14 yrs and 67% were females. Mean pulmonary artery pressure averaged 57 ± 16 mmHg and cardiac index 2.4 ± 0.9 L/m/m2. We hypothesized that severe impairment in right ventricular function would be associated with reduced post-transplant survival. Among the 78 patients with a cardiac index of < 1.8 L/m/m2 (mean 1.5 ± 0.2), 1- and 3-yr survival was 70% and 58%, compared with 75% and 65%, respectively, among the 213 recipients with a cardiac index of > 1.8 L/m/m2 (mean 2.8 ± 0.9). The Hazard Ratio was 1.23 (95% CI: 0.83-1.82; p=0.3. Pulmonary artery pressure was identical in these two groups. Additional analyses for other variables and 90-day mortality is ongoing. In conclusion, In this preliminary analysis, impaired cardiac index was not clearly associated with survival after lung transplantation for PPH. Further research is required to identify risk factors for early mortality.