Materials and Methods
The study was approved by the National Medical Ethics Committee (NMEC;
Komisija Republike Slovenije za medicinsko etiko, No. 0120-133/2021/3,
14.5.2021). Written patient informed consent was waived by NMEC as this
was a non-interventional study.
We analyzed 127 anonymized coronary CTAs from our hospital’s picture
archiving and communication system (PACS). The anonymized CTAs included
gender, age, height, and weight of the patient in the metadata. 57 CTAs
were excluded from further analysis due to one or more of the following
reasons: bicuspid aortic valve, poor contrast, poor leaflet visibility,
motion artefacts, calcifications of aortic valve leaflets, and aortic
root diameter ≥ 45 mm. On the remaining 70 CTAs all aortic valves were
tricuspid, without calcifications and the diameter of aortic root was
< 45 mm. All valve analyses were performed in end-diastolic
phase of the cardiac cycle. The CTAs were imported into Mimimics
Innovation Suite v. 21.0 (Materialise, Leuven, Belgium) where aortic
roots were segmented. Several geometric points of interest (Fig. 1) were
marked on each segmented aortic root in 3D space. Spline tool was used
to define coaptation surfaces, leaflet attachments, commissural heights
and annular and sinutubular perimeters for each patient. The points and
splines defined by 3D coordinates were then imported into Mathematica
v12.0 (Wofram Research, UK) where dedicated code was used to reconstruct
the aortic valve in 3D space from the measured points and splines,
define different planes, calculate relevant angles, lengths, and areas
for each patient. Central coaptation point was calculated as a mean of
the tips of the three geometric height splines.
Asymmetry of the three leaflets in individual patients was assessed by
calculating absolute and relative differences. Absolute difference for
selected measurement was defined as difference between the largest and
the smallest of the three leaflets. Relative difference for selected
measurement was defined as absolute difference divided by the mean of
the three leaflets.
Statistical data analysis was performed using JASP v 0.14.1 (University
of Amsterdam, Netherlands). Normal distribution of variables was
assessed using the Shapiro-Wilk test. Continuous variables are reported
as mean ± standard deviation. Differences were analyzed using
Independent samples t-test and Repeated measures ANOVA with post hoc
test with Bonferroni correction. In analysis of asymmetry One sample t
– test and Wilcoxon signed-rank test were used. P-value of less than
0.05 was considered statistically significant.