Two-dimensional echocardiographic assessment
All patients underwent comprehensive two-dimensional (2D)
echocardiographic examinations, performed with a Vivid E9 (GE Vingmed,
Horten, Norway) ultrasound machine equipped with a M5S probe, according
to current recommendations [15]. Three experienced researchers
performed offline data analysis using dedicated software (EchoPAC BT
12).
LV dimensions, systolic and diastolic function were assessed according
to international recommendations [14-16]. LV volumes and LV ejection
fraction (EF) were measured using the biplane Simpson method from the
apical four- and two-chamber views. Using pulsed-wave tissue Doppler
imaging (TDI) at the septal and lateral site of the mitral annulus, we
calculated myocardial velocities and we estimated LV filling pressures
from the ratio of early diastolic transmitral velocity (E) to average eā
wave. For LV global longitudinal strain (GLS), we used high frame rate
acquisitions (50-70 frames per second) and a 17-segment model by speckle
tracking echocardiography (STE), as previously described [17].
Conventional parameters of RV function such as tricuspid annular plane
systolic excursion (TAPSE), peak systolic TDI velocity of the tricuspid
annulus (S wave) and RV fractional area change (RV-FAC) were measured
from apical RV-focused view, according to current guidelines [15,
18]. For RV strain analysis we used software designed for the LV
(EchoPAC ā Q Analysis package) and we manually traced the endocardial
border of the RV from the apical RV-focused view, as recommended [19,
20]. The RV free wall (RVFW) and the interventricular septum were each
divided into three segments. The global longitudinal strain of the RV
(GLS-RV) represents the average of all six segmental strain values. The
longitudinal strain of the RVFW (RVFW-LS) is the average of the
segmental values of the RVFW. Estimation of pulmonary artery systolic
pressure (PASP) was made using the gradient between the RV and the right
atrium (RA) ā obtained from the continuous-wave Doppler spectrum of the
tricuspid regurgitation (TR) jet ā and the estimated RA pressure, based
on the inferior vena cava (IVC) diameter and respiratory changes
[15]. TR severity was graded based on qualitative Doppler criteria,
such as color flow jet area and the shape and density of the TR jet
envelope [21].