Significance of Pulmonary Vascular Resistance and Diastolic Pressure Gradient on the New Definition of Combined Post-Capillary Pulmonary Hypertension

Pulmonary hypertension (PH) caused by left-sided heart disease (LHD-PH) is classified into 2 types: isolated post-capillary PH (Ipc-PH) and combined pre- and post-capillary PH (Cpc-PH). However, the impact of pulmonary vascular resistance (PVR) or diastolic pressure gradient (DPG) on the prognosis of LHD-PH has varied among previous studies. Thus, we verified the significance of PVR or DPG on the prognosis of LHD-PH in our series.We analyzed 243 consecutive LHD-PH patients. The patients were divided into 3 groups: Group A, patients with PVR ≤ 3 Wood unit (WU) and DPG < 7 mmHg; Group B, patients with either PVR > 3 WU or DPG ≥ 7 mmHg; and Group C, patients with PVR > 3 WU and DPG ≥ 7 mmHg.The Kaplan-Meier curve demonstrated that Group B had lower cardiac death-free survival compared with Group A, whereas no significant differences were observed when compared with Group C. In the Cox hazard model, DPG was not associated with cardiac death in the LHD-PH patients. However, only in the ischemic heart disease group, patients with DPG ≥ 7 mmHg had worse prognosis compared with those with normal DPG.The cardiac death-free rate of patients with either increased PVR or DPG was close to that of patients with both increased PVR and DPG. It seems reasonable to define Cpc-PH only by PVR in the new criteria. However, the significance of DPG in LHD-PH might be dependent on the underlying cause of LHD-PH.