Table 3.
Multiple regression models regarding the association of flow parameters (helical and vortical flow formation, eccentricity, normalized flow displacement, WSSpeak) with potential influencing factors, parameter estimates and p-values of final models after stepwise selection. Only parameters remaining in the final model are shown.
| Flow parameter (Model) |
Independent Variable |
All subjects (n=74) Estimate β ± SE (p-value) |
Patients (n=37) Estimate β ± SE (p-value) |
|---|---|---|---|
| Helical flow * | Age | −0.04 ± 0.02 (p=0.14) | |
| Bicuspid morphology | 0.98 ± 0.48 (p=0.0406) | 1.13 ± 0.44 (p=0.0098) | |
| Aortic orifice area | −1.81 ± 0.38 (p<0.0001) | ||
| Vortical flow* | Bicuspid morphology | 0.80 ± 0.38 (p=0.0375) | 0.74 ± 0.38 (p=0.0536) |
| Aortic diameter | 0.12 ± 0.06 (p=0.0522) | 0.10 ± 0.07 (p=0.14) | |
| Aortic orifice area | −1.84 ± 0.55 (p=0.0009) | −1.42 ± 0.64 (p=0.0274) | |
| AS (y/n) | −2.71 ± 1.22 (p=0.0258) | - | |
| Eccentricity*† | Aortic orifice area | −2.74 ± 0.47 (p<0.0001) | −2.17 ± 0.81 (p=0.0070) |
| Normalized flow displacement, S1‡ | Bicuspid morphology | 0.032 ± 0.02 (p=0.11) | |
| Ejection fraction | 0.002 ± 0.001 (p=0.0668) | ||
| AS × Aortic diameter | 0.002 ± 0.0003 (p<0.0001) | - | |
| Normalized flow displacement, S2‡ | Age | 0.001 ± 0.0004 (p=0.0788) | |
| Aortic orifice area | −0.039 ± 0.004 (p<0.0001) | −0.041 ± 0.01 (p=0.0021) | |
| Normalized flow displacement, S3‡ | Age | 0.001 ± 0.001 (p=0.0662) | |
| AS × Age | 0.002 ± 0.0002 (p<0.0001) | - | |
| WSSpeak, S1‡ | Ejection fraction | 0.01 ± 0.01 (p=0.0269) | 0.02 ± 0.01 (p=0.0474) |
| AS × Ejection fraction | 0.01 ± 0.001 (p<0.0001) | - | |
| WSSpeak, S2‡ | Age | −0.01 ± 0.003 (p=0.0002) | |
| Bicuspid morphology | 0.22 ± 0.13 (p=0.0926) | ||
| AS × Ejection fraction | 0.01 ± 0.002 (p<0.0001) | - | |
| AS × Aortic orifice area | −0.22 ± 0.07 (p=0.0043) | - | |
| WSSpeak, S3‡ | Age | −0.01 ± 0.003 (p<0.0001) | −0.01 ± 0.004 (p=0.0469) |
| Ejection fraction | 0.02 ± 0.01 (p=0.0592) | ||
| AS × Ejection fraction | 0.01 ± 0.004 (p=0.0004) | - | |
| AS × Aortic diameter | −0.01 ± 0.01 (p=0.0859) | - | |
| AS × Aortic orifice area | −0.13 ± 0.07 (p=0.0540) | - | |
*
Ordinal logistic regression
†
Model without AS (y/n) and interaction terms as introduction of these led to quasi-complete separation
‡
Linear regression
- Parameter not presented to selection process