Note: PAD: pulmonary artery diameter; TRPG: tricuspid valve regurgitation pressure gradientbiggest; PASP: pulmonary arterial systolic pressure; TAPSE: tricuspid annular plane systolic excursion; IVCmax: maximum diameter of the inferior vena cava; IVCmin: minimum diameter of the inferior vena cava; ICV-CI: inferior vena cava collapse index. * p < 0.05 compared with healthy group;# p < 0.05 compared with severe patients group