Table 1.

Definitions of Pulmonary Hypertension Used in Clinical Research

Hemodynamic Parameter [1]	Normal Value	Abnormal Value
Systolic pulmonary artery pressure (SPAP)	15-30 mmHg	> 30 or ≥ 40 mmHg
Mean pulmonary artery pressure (MPAP)	9-16 mmHg	Moderate: > 18 mmHg Significant: > 25 mmHg Exercise-induced: > 30 mmHg
Pulmonary vascular resistance (PVR) = (MPAP – PAOP) X 80/CO	60-120 dyn·s·cm-5 1.1-1.4 Wood unit	Mild: > 125 dyn s cm-5 Moderate: > 200-300 dyn s cm-5 Severe: > 600dyn s cm-5
Indexed pulmonary vascular resistance (PVRI) = (MPAP – PAOP) X 80/CI	250-340 dyn·s·cm-5·m-2
Pulmonary to systemic vascular resistance index (PVRI/SVRI) X 100%	< 10%
Trans-pulmonary gradient (MPAP – PAOP)	< 14 mmHg
Mean pulmonary to systemic pressure ratio (MPAP/MAP) X 100%	< 25%	Moderate: 33-50% Severe: > 50%
Mean systemic to pulmonary pressure ratio (MAP/MPAP) X 100%	> 4	< 4 [3]

CO: cardiac output, CI: cardiac index, PAOP: pulmonary artery occlusion pressure.