Internal versus External Annuloplasty in Aortic Valve Repair: Implications from MS-CT Data

Background: Aortic valve (AV) repair is increasingly performed in patients with aortic valve regurgitation. A reproducible stabilization of AV annulus is crucial. We aimed to analyze the anatomic structure of functional aortic root based on MS-CT imaging data.

Methods: We retrospectively identified 326 consecutive patients with different AV pathologies who underwent preprocedural cardiac MS-CT examination. We subdivided study population according to the underlying AV pathology: 25 patients with aortic regurgitation (AR subgroup) (73, 68% male), 243 patients with aortic stenosis (AS subgroup) (73 years, 68% male), and 58 patients with normal tricuspid AVs (normal AV subgroup) (mean age 76, 36% male).

The following annular dimensions were measured using MS-CT data: max. and min. annulus diameter, AV annular area, projected and anatomic AV annular perimeter. Based on these measurements, AV annular eccentricity index was calculated. In addition, we defined the “surgical RCS distance” as the distance between deepest accessible external surgical dissection point and the hinge point of right coronary cusp in the mid-right coronary sinus. Furthermore, we assessed the tissue components of the basal AV annular plane, distinguishing between muscular and membranous tissue proportions.

Results: AV annular area was significantly larger in the AR subgroup as compared with the AS subgroup (5.7 ± 1 vs. 5.1 ± 0.8 cm²; p = 0.003) and normal AV subgroup (5.7 ± 1 vs. 4.8 ± 0.8 cm²; p < 0.001). Surgical RCS distance is significantly increased in the AR subgroup as compared with the AS subgroup (12.8 ± 2.7 vs. 7.5 ± 3.6 mm; p < 0.001) and to the normal AV subgroup (12.8 ± 2.7 vs. 8.7 ± 3 mm; p < 0.001). We found a significant difference in the relation of fibrous versus muscular component of the basal AV ring when comparing three patients’ cohorts. Myocardial component of the basal ring was significantly smaller in the AR subgroup when compared with the AS subgroup (37.5 ± 5.1 vs. 40.5 ± 5.5%; p = 0.039) and the normal AV subgroup (37.5 ± 5.1 vs. 44.3 ± 10.2%; p = 0.001).

Conclusion: MS-CT data analysis allows the quantitative analysis of complex aortic root anatomy in different aortic valve/aortic morphologies. External surgical dissection and AV annular stabilization in the right coronary sinus seem to be more demanding in AR subgroup. The relation between fibrous and muscular component of the basal AV ring changes significantly in patients who develop severe aortic regurgitation.