Background
Methods
Patient recruitment
Cardiovascular magnetic resonance acquisition
4D flow assessment
Flow angle | The angle of deviation from the center of the aortic lumen |
Flow displacement | The distance of flow jet deviation from the center of the aortic lumen indexed to ascending aortic diameter |
Rotational flow | The blood flow circling within the aortic plane |
WSScircavg | Circumferentially averaged systolic wall shear stress - surrogate marker for the friction the blood flow exerts onto the aortic wall |
In-plane wall shear stress | (the ‘rotational’ component) exerted by the blood circling within the plane along the aortic wall |
Through-plane wall shear stress | Exerted by the blood flowing through the vessel. |
Statistical analysis
Results
General demographics and valve characterization
Healthy Subjects | BAV- native | AVR-mechanical | AVR-tissue | Ross | ||
---|---|---|---|---|---|---|
Total number (male) | 30 (23) | 30 (23) | 11 (10) | 10 (9) | 9 (8) | |
Time after operation in months (range) | 6 (3–14) | 9 (1–37) | 126 (1–268) | |||
Indication for AVR: | ||||||
Aortic stenosis | 4 | 7 | 8 | |||
Aortic regurgitation | 5 | 1 | 1 | |||
Both | 2 | 2 | ||||
Fusion pattern pre-AVR: | ||||||
RL-BAV | 7 | 5 | Data | |||
RN-BAV | 2 | 5 | unavailable | |||
Others | 2 | |||||
Flow pattern post-AVR: | ||||||
Normal flow | 30 | 5 (17%) | 8 (73%) | 0 | 6 (67%) | |
Right-handed flow | 21 (70%) | 2 (18%) | 8 (80%) | 2 (22%) | ||
Left-handed flow | 1 (3%) | 1 (9%) | 1 (10%) | 1 (11%) | ||
Complex flow | 3 (10%) | 0 | 1 (10%) |
Healthy Subjects n = 30 | BAV- native n = 30 | AVR-mechanical n = 11 | AVR-tissue n = 10 | Ross n = 9 | ANOVA | |
---|---|---|---|---|---|---|
Age in years | 43 ± 17 | 42 ± 16 | 42 ± 12 | 58 ± 11 | 24 ± 12 | p < 0.001 |
Systolic flow angle (°) | 7.5 ± 5.3 | 25.6 ± 13.3* | 16.5 ± 9.6 | 16.2 ± 8.5 | 9.8 ± 4.9† | p < 0.001 |
Normalised flow displacement | 0.038 ± 0.036 | 0.133 ± 0.072* | 0.083 ± 0.076 | 0.163 ± 0.064* | 0.096 ± 0.067 | p < 0.001 |
Absolute rotational flow (mm2/ms) | 3.8 ± 3.1 | 26.6 ± 16.6* | 7.2 ± 3.9† | 20.7 ± 8.8* | 10.6 ± 10.5† | p < 0.001 |
Mean systolic WSScircavg (N/m2) | 0.58 ± 0.15 | 0.77 ± 0.23* | 0.67 ± 0.20 | 0.68 ± 0.20 | 0.80 ± 0.35 | p = 0.012 |
Absolute systolic in-plane (rotational) WSS (N/m2) | 0.07 ± 0.06 | 0.40 ± 0.28* | 0.19 ± 0.13† | 0.38 ± 0.19* | 0.21 ± 0.17 | p < 0.001 |
Max systolic through-plane WSS (N/m2) | 0.76 ± 0.21 | 0.95 ± 0.44 | 0.91 ± 0.38 | 0.78 ± 0.215 | 1.03 ± 0.65 | p = 0.206 |
RA-LP systolic WSScircavg (N/m2) | −0.12 ± 0.13 | 0.22 ± 0.31* | 0.27 ± 0.22* | 0.36 ± 0.26* | 0.24 ± 0.67 | p < 0.001 |
Peak velocity (m/s) | – | 2.3 ± 0.8 | 2.1 ± 0.5 | 2.1 ± 0.3 | 1.9 ± 0.8 | p = 0.387 |
Ascending aortic diameter (mm) | 28.6 ± 4.3 | 35.0 ± 6.7* | 35.9 ± 4.4* | 37.9 ± 5.2* | 30.4 ± 8.3 | p < 0.001 |
Diameter at sino-tubuar junction (mm) | 27.9 ± 3.6 | 32.4 ± 6.4* | 31.7 ± 7.8 | 32.9 ± 3.3 | 31.0 ± 6.0 | p = 0.003 |
Diameter at sinuses (mm) | 30.8 ± 3.5 | 32.9 ± 5.8 | 34.1 ± 6.7 (pre-AVR) | 32.1 ± 2.3 (pre-AVR) | 35.9 ± 5.7 | p = 0.068 |
Aortic regurgitant fraction (%) | – | 8.8 ± 9.9 | 3.7 ± 2.8 | 5.8 ± 7.5 | 22.8 ± 20.6† | p = 0.002 |
Left ventricular ejection fraction (%) | – | 68 ± 6 | 67 ± 15 | 70 ± 8 | 65 ± 10 | p = 0.687 |
Flow patterns after aortic valve replacement
Flow angle and flow displacement after aortic valve replacement
Wall shear stress after aortic valve replacement
Individual changes in aortic flow after aortic valve replacement
AVR-mechanical | AVR-tissue | |||||
---|---|---|---|---|---|---|
Pre-AVR | Post-AVR | p-value | Pre-AVR | Post-AVR | p-value | |
Number | 10 | 10 | 6 | 6 | ||
Absolute rotational flow (mm2/ms) | 30.4 ± 16.3 | 7.3 ± 4.1 | p = 0.001 | 35.6 ± 23.1 | 22.2 ± 6.0 | p = 0.18 |
Systolic WSScircavg (N/m2) | 1.02 ± 0.21 | 0.68 ± 0.21 | p = 0.001 | 1.04 ± 0.20 | 0.70 ± 0.21 | p = 0.048 |
Absolute systolic in-plane WSS (N/m2) | 0.47 ± 0.20 | 0.20 ± 0.13 | p = 0.001 | 0.56 ± 0.32 | 0.44 ± 0.19 | p = 0.41 |
Max systolic through-plane WSS (N/m2) | 1.43 ± 0.54 | 0.92 ± 0.39 | p = 0.04 | 1.47 ± 0.34 | 0.75 ± 0.21 | p = 0.01 |
RA-LP systolic WSScircavg (N/m2) | 0.55 ± 0.66 | 0.28 ± 0.23 | p = 0.19 | 0.77 ± 0.29 | 0.25 ± 0.27 | p = 0.03 |
Systolic flow angle (°) | 26.5 ± 9.3 | 17.1 ± 9.8 | p = 0.77 | 23.8 ± 9.4 | 20.2 ± 7.2 | p = 0.41 |
Normalised flow displacement | 0.126 ± 0.093 | 0.069 ± 0.065 | p = 0.18 | 0.166 ± 0.053 | 0.141 ± 0.068 | p = 0.54 |
Peak velocity (m/s) | 3.4 ± 1.5 | 2.0 ± 0.5 | p = 0.02 | 3.7 ± 0.8 | 2.1 ± 0.4 | p = 0.001 |
Regurgitant fraction (%) | 38 ± 19 | 3 ± 2 | p < 0.001 | 12 ± 14 | 2 ± 2 | p = 0.21 |
Left ventricular ejection fraction (%) | 71 ± 9 | 68 ± 16 | p = 0.68 | 75 ± 9 | 75 ± 5 | p = 0.91 |