Echocardiography:
Each patient underwent 2D-transthoracic echocardiogram (TTE) before
TMVI, 2D-TTE pre-discharge and further TTEs at 1 and 3-months. Patients
were excluded if TTE data were not available or acquired outside the
study time period. TTE images were obtained using an EPIQ 7 (Phillips
Healthcare, Eindhoven, the Netherlands) or Vivid 95 (GE Medical Systems,
Horten, Norway) ultrasound machine. Standardized measurements were
performed at the time of image acquisition or offline using local
hospital reporting systems in accordance with guidelines from the
American Society of Echocardiography [14]. Measurements using
2D-speckle tracing echocardiography (STE) were performed offline using
EchoInsight Pro (Epsilon Imaging, Michigan, USA) with a frame rate of at
least 30 frames/s (Figure 1).
Patients were stratified into two groups based on the pre-operative LV
ejection fraction (EF). LV function was quantified by recording LVEF
using the Simpson’s biplane method, LV end-diastolic dimension (LVEDD),
end-systolic dimension (LVESD), end-diastolic volume (LVEDV),
end-systolic volume (LVESV), LV global longitudinal strain (GLS),
circumferential and radial strain (Figure 2). Global RV systolic
function was recorded qualitatively as a categorical variable (mild,
moderate or severe) and quantitatively by: pulmonary artery systolic
pressure (PASP), RV fractional area change (RVFAC), RV longitudinal
myocardial velocity (RVS’), RV basal diameter, RV free wall longitudinal
strain (FWLS) and tricuspid annular plane systolic excursion (TAPSE).
RVFWLS was calculated as the systolic peak of the average curve from a
6-segment ROI after manually excluding the septal segments [15, 16]
and defined as normal if < -20% [14, 17, 18].
Degree of valvular regurgitation of the mitral and tricuspid valves were
recorded qualitatively as categorical variables (mild, moderate,
moderate-severe, severe), and in the case of MR, quantitatively by:
proximal isovelocity surface area (PISA), regurgitation fraction (RF),
end regurgitant orifice area (EROA), regurgitant volume and vena
contracta (VC).
All 2D-STE measurements were
analyzed offline by two experienced independent observers (SH & NB).
For assessment of intra- and inter-observer variability, each observer
was blinded to the other observer’s results. Measurements were repeated
after a >4-week interval by the same observers blinded to
the initial measurements and reproducibility was comparable with
quaternary centers experienced in the technique (Table 1). 2D-TTE image
quality was sufficient to perform volumetric analysis in all 46
patients, but on 41 occasions (41/138; 30% of all TTEs analyzed), the
image quality was insufficient or not available to perform full 2D-STE
analysis.