Internal versus External Annuloplasty Design during Aortic Valve Repair: Anatomical Implications from Consecutive MS-CT data

Objective: Knowledge of precise aortic root morphology is crucial in patients with aortic regurgitation to achieve reproducible results of aortic valve repair. External annuloplasty has been proposed to stabilize dilated aortic valve (AV) annulus. However, there are anatomic limitations (especially in the segment of right coronary sinus) which may limit the efficacy of external aortic annulus stabilization. We aimed to address these anatomic limitations in different subgroups with aortic valve disease.

Methods: We systematically analyzed cardiac multi-slice computer tomography (MS-CT) data of 287 consecutive TAVR patients (mean age 77.6 ± 10.8 years, 62.2% male) using 3-mensio Structural Heart™ imaging program. Our study population consisted of 3 subgroups: tricuspid aortic regurgitation (AR; n: 29), bicuspid aortic valve stenosis (BAV-AS; n: 25) and tricuspid aortic valve stenosis (TAV-AS; n: 238). The following parameters were measured: min. and max. annulus diameters, and AV-annular-eccentricity-index. Furthermore, we measured the maximal distance between insertion line of right coronary cusp (i.e., mid-part of the right coronary sinus) and the deepest externally accessible point of surgical dissection between LVOT and RVOT. These parameters were compared between groups using the Kruskal-Wallis-Test and one-way ANOVA.

Results: Our MS-CT based measurements revealed that the mean distance between insertion line of right coronary cusp and the deepest externally accessible point of surgical dissection was 8.3 ± 4 mm (range: 5.9–10.9 mm) in the whole study population. The above-mentioned distance differed significantly in the three study groups, depending on aortic valve morphology: it was significantly larger in the AR subgroup versus TAV-AS subgroup (12.3 ± 3 mm vs. 7.4 ± 3.5 mm; p < 0.001) and in the BAV-AS subgroup versus TAV-AS subgroup (12.9 ± 4.2 mm vs. 7.4 ± 3.5 mm; p < 0.001). AV annular eccentricity index was the most severe in the AR group as compared with BAV-AS (27.3 ± 9.3% versus 18.3 ± 7.7%; p: 0.002) and TAV-AS patients (27.3 ± 9.3% versus 20.2 ± 8.9%; p: 0.001).

Conclusion: Surgical dissection plane should be extended for at least 10 mm between LVOT and RVOT to reach the aortic annular level from externally in the right coronary sinus. Therefore, external approach might be technically demanding and suboptimal in patients with BAV and aortic regurgitation, while an internal annuloplasty design seems to be beneficial.