Geometric Changes of Aortic Valve Annulus during Cardiac Cycle: Impact on Aortic Valve Repair

Objectives: The growing experience in aortic valve (AV) repair showed that annular stabilization is a crucial component to achieve stable long-term results after aortic valve repair. Dynamic changes of the AV annulus during cardiac cycle may have an impact on annuloplasty design.

Methods: We retrospectively analyzed full cardiac cycle multi-slice computed tomography (MS-CT) data of 58 consecutive patients (mean age 75.9 ± 6.5 years, 36% male) with normally functioning tricuspid aortic valves (normal AV subgroup). The following CT parameters were measured in systole and diastole: maximum, minimum and mean AV annulus diameter, AV annular area, and AV annular perimeter. Furthermore, we calculated AV annular eccentricity index (%) (max AV annulus × 100/min AV annulus) −100) in systole and diastole. Subsequently, MS-CT data of 20 patients with severe aortic regurgitation were analyzed (AR subgroup).

Results: There was a significant decrease in mean AV annulus diameter from systole to diastole (i.e., 24.6 ± 2.5 mm versus 23.9 ± 2.4 mm, respectively, p < 0.001) which predominantly occurred in the short axis (i.e., 21.2 ± 2.4 mm in systole versus 19.9 ± 2.3 mm in diastole; p < 0.001). Mean AV annular area decreased significantly in diastole (i.e., 467.5 ± 94.5 mm² in systole versus 444.8 ± 86.1 mm² in diastole, p = 0.012). Annular eccentricity index increased significantly in diastole (33.0 ± 12.2% in systole versus 41.4 ± 13.5% in diastole; p < 0.001). Furthermore, we found an inverse linear correlation between mean AV annulus diameter and annular eccentricity index (r = −0.40, p = 0.03). Diastolic annular eccentricity index was significantly reduced in the AR subgroup (i.e., 41.4 ± 13.5% in the normal AV subgroup versus 33.7 ± 14.8% in the AR cohort, p = 0.035)

Conclusion: Normal aortic valve annulus undergoes important geometric deformation during cardiac cycle which is significantly reduced in the AR scenario. Novel AV annuloplasty system should ideally adapt for this marked diastolic annular eccentricity and thereby allow for dynamic aortic root changes during the cardiac cycle.