RV function assessment
TAPSE was defined as the peak excursion of tricuspid annulus from
end-diastole to end-systole, and was measured from the apical
four-chamber view by placing the M-mode cursor through the lateral
tricuspid annulus. TAPSE less than 17 mm indicated RV dysfunction
[12].
The diameter changes of inferior vena cava (IVC) during the respiratory
cycle were measured from the IVC long axis view by M-mode. The minimum
diameter of the inferior vena cava (IVCmin) was measured in the
inspiratory phase and the maximum diameter of the inferior vena cava
(IVCmax) was measured in the expiratory phase when breathing
spontaneously. The inferior vena cava collapse index (ICV-CI) was
calculated by the formula of (IVCmax-IVCmin) / IVCmax × 100%.
The diameter of pulmonary artery (PAD) was measured from
parasternal short-axis view by two-dimensional echocardiography.
Tricuspid valve regurgitation pressure gradient biggest (TRPG) was
measured and pulmonary arterial systolic pressure (PASP) was estimated
indirectly by tricuspid regurgitation velocity with the addition of
right atrial pressure, assuming no significant right ventricular outflow
tract (RVOT) obstruction.