Altered stresses and dynamics after single and double annuloplasty ring for aortic valve repair.

OBJECTIVES

Aortic valve repair procedures for the treatment of isolated aortic valve insufficiency may be improved by stabilizing the functional aortic annulus using a double annuloplasty ring at the aortic annulus and sinotubular junction (STJ). The objective of this study was to compare the geometrical changes and aortic root stress distribution when using a single subvalvular ring and a double sub- and supravalvular ring in vivo.

METHODS

Both the single- and double-ring procedures were performed successively in nine 80-kg pigs. Measurements were performed intraoperatively using sonomicrometry crystals in the aortic root to evaluate geometrical changes and annular and STJ force transducers measuring the segmental radial stress distribution.

RESULTS

The total force in the STJ was significantly reduced after the double-ring procedure from 1.7 ± 0.6 to 0.04 ± 1.1 N (P = 0.001). The double-ring procedure significantly reduced the STJ area from 234.8 ± 37.6 to 147.5 ± 31.8 mm2 (P = 0.001) and expansibility from 17 ± 6% to 8 ± 3% (P = 0.001). With the single-ring procedure, the STJ shape was circular but became more oval with the double-ring procedure. The double-ring procedure did not affect stress distribution or geometry in the aortic annulus.

CONCLUSIONS

The double-ring procedure stabilized the whole aortic root by reducing radial stress distribution in the STJ more efficiently than the single-ring procedure. Both area and expansibility were reduced with the double-ring procedure. These results confirm the importance of addressing the entire functional aortic annulus for optimal aortic valve repair procedures.