Agreement between 3D TTE and TOE measurements
The Bland-Altman analysis showed a good agreement between 3D TTE and TOE
measurements of mitral annular area and perimeter for the whole study
cohort (Figures 3a and 3b) as well as in the subgroups with MV pathology
(Figures 3c and 3d) and those with normal MV (Figures 3e and 3f). More
specifically, for mitral annular area measurements, the Bland–Altman
analysis indicated a mean difference between 3D TOE and TTE of a) -0.34
cm2 (CI: 0.56–0.11cm2) with limits
of agreement -2.6–1.8cm2, for all subjects, b) of
-0.57 cm2(CI: 0.89–0.25cm2) with
limits of agreement -2.8–1.6cm2, for those with MV
pathology c) of -0.08 cm2(CI:
0.40–0.22cm2) with limits of agreement
-2.2–2.0cm2, for those with normal MV. For mitral
annular perimeter measurements similarly, the Bland–Altman method
indicated a mean difference between 3D TOE and TTE of a) -0.19 cm (CI:
0.33–0.06cm) with limits of agreement -1.5-1.1cm, for all subjects b)
of 0.34 cm (CI: 0.17–0.51cm) with limits of agreement -0.9–1.5cm, for
those with MV pathology c) of 0.04 cm (CI: 0.16–0.24cm) with limits of
agreement -1.3–1.4cm, for those with normal MV. Therefore, the
Bland–Altman analysis demonstrated acceptable limits of agreement
between 3D TTE and TOE MV measurements.
We also calculated the intraclass correlation coefficient (ICC) for
every parameter among the 3D TTE and TOE (with the same operator in
every measurement for all patients). The ICC for MV annular area was
0.94 (CI: 0.91–0.95) whereas it was 0.92 for MV annular perimeter (CI:
0.88–0.95) between 3D TTE and TOE, in all subjects. For tenting area
and posterior leaflet length, the ICC was 0.68 (CI: 0.56-0.77) and 0.69
(CI: 0.57-0.78) respectively.
Similar values of ICC were obtained for 3D MV parameters both in those
with MV pathology and those with normal MV.