Comparison of Dacron ring and suture annuloplasty for aortic valve repair-a porcine study

Abstract

Background: A subvalvular annuloplasty is often used for aortic valve repair in patients with isolated aortic regurgitation with aortic annulus dilatation. Our aim was to characterize and compare annulus geometry and dynamics of the Dacron ring and suture annuloplasty and compare it with the native aortic annulus under standardized conditions.

Methods: We randomized 29 pigs of 80 kg into a Dacron ring group, a suture annuloplasty group and a native control group. The assessment was performed using sonomicrometry crystals for evaluation of dynamic geometry, and pressure measurements and echocardiography to evaluate valve performance.

Results: Aortic annulus area (AAA) was significantly reduced in the Dacron and Suture group compared with the Native group. Expansibility was similar and within normal physiologic limits in all three groups (Native: 12%±7%; Dacron: 11%±3%; Suture: 10%±4%). The largest segmental expansion was observed at the right coronary sinus (RC) in the Native and Dacron group but in the Suture group there was no significant difference between segments. The aortic annulus was primarily oval in systole and became more circular in diastole in the Native and Dacron group, however, in the Suture group, the sphericity remained relatively unchanged throughout the cardiac cycle.

Conclusions: This study is the first to describe and compare detailed segmental geometry of the Dacron ring and suture annuloplasty in a standardized porcine model. The two annuloplasties effectively downsized the aortic annulus, while expansibility was maintained. Each annuloplasty had its own geometrical characteristics, but the Dacron ring was more similar to the native aortic annulus than the suture annuloplasty. This study suggests that the Dacron ring offers a more physiological and standardized support by mimicking the geometry and dynamics of the native aortic annulus and thus is a preferable choice over the suture annuloplasty for valve-sparing aortic root procedures.

Keywords: Aortic annulus; Dacron ring annuloplasty; aortic regurgitation; dynamic characterization; suture annuloplasty; valve-sparing procedures.

Figure 1

Schematic illustration of the position of the six sonomicrometry crystals at the level of the aortic annulus. (A) The aortic annulus from a cross-sectional view with the sonomicrometry crystals numbered 1–6; (B) the aortic root from a longitudinal view: (a) sinotubular junction; (b) sinuses of Valsalva; (c) aortic annulus; (d) sonomicrometry crystal.

Figure 2

Schematic illustration of the three groups. (A) Native aortic annulus; (B) Dacron ring annuloplasty; (C) suture annuloplasty.

Figure 3

Aortic annulus area (AAA) (left) and aortic annulus circumference (AAC) (right) presented at four defined time points throughout the cardiac cycle (ED, MS, ES, MD). Mean + standard deviation. (A) Native group; (B) Dacron group; (C) Suture group. ED, end-diastole; MS, mid-systole; ES, end-systole; MD, mid-diastole.

Figure 4

Cross-sectional diameters NC-LR, RC-LN and LC-RN presented at four defined time points throughout the cardiac cycle (ED, MS, ES, MD). Mean ± standard deviation. (A) Native group; (B) Dacron group; (C) Suture group. ED, end-diastole; MS, mid-systole; ES, end-systole; MD, mid-diastole; NC, non-coronary sinus; LR, left/right interleaflet triangle; RC, right coronary sinus; LN, left/non-coronary interleaflet triangle; LC, left coronary sinus; RN, right/non-coronary interleaflet triangle.