BACKGROUND: Pulmonary hypertension (PH) associated with end stage liver disease is rare but the risk of hemodynamic deterioration during liver transplantation may be high. This study was done to characterize the pulmonary hemodynamics during liver transplantation and to seek the relationship between pulmonary artery pressure (PAP) and other hemodynamic variables. METHODS: One hundred patients undergoing liver transplantation were chosen and we divided patients into normal and PH groups (mean pulmonary artery pressure [MPAP] > 25 mmHg). Hemodynamic data was collected throughout the surgery. Studied variables between groups were analyzed with an unpaired t-test. The relationship between MPAP and other hemodynamic variables was analyzed with a linear regression test. Survival analysis was performed by cumulative survival analysis (Logrank test). RESULTS: Incidence of PH during liver transplantation was 34%, and true PH (pulmonary vascular resistance index [PVRI] > 150 dyne.sec/cm5/m2, MPAP > 25 mmHg) was 7%. MPAP, systemic vascular resistance index, cardiac index, right ventricular ejection fraction, maximum elastance, central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), and right ventricular end-diastolic volume index were significantly higher in the PH group. In the PH group, right ventricular function curve was abnormal. MPAP correlated significantly with PAOP, and CVP (P < 0.01). One year survival rate showed no significant difference between groups (Logrank test P = 0.49). CONCLUSIONS: Episodes of increased pulmonary artery pressure during liver transplantation was not infrequent. PAP was more dependent on preloads. In patients with high PAP, RV diastolic dysfunction was usually observed. Early mortality rate after liver transplantation was not associated with PH.