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.