An Expansible Aortic Ring in Aortic Root Remodeling: Exact Position, Pulsatility, Effectiveness, and Stability in Three-Dimensional CT Study

External aortic annuloplasty with a dedicated expansible ring improves outcomes in remodeling root repair compared with homemade Dacron ring

OBJECTIVES

In remodeling valve-sparing root replacement with external annuloplasty, we compare long-term outcomes of a calibrated expansible extra-aortic ring with a homemade Dacron ring.

METHODS

All patients (2003-2020) operated for root aneurysm with/without aortic insufficiency (AI) were included. The standardized CAVIAAR (conservation aortique valvulaire dans les insuffisances aortiques et anévrysmes de la racine-Valve sparing in aortic insufficiencies and root aneurysms) technique was root remodeling and external annuloplasty ring with the EXTRA-AORTIC Ring or homemade Dacron ring.

RESULTS

Among 486 patients (age 52.3 ± 14.0 years) operated for root aneurysm, 375 (repair rate: 77.1%) underwent root remodeling with annuloplasty (extra-aortic ring, n = 289, vs Dacron ring, n = 86). At 10 years (median follow-up, 4.08 years' interquartile range, 1.95-7.61), unmatched and matched analysis showed that patients with extra-aortic ring had greater survival, similar to the general population (93.3% vs 79.9%, P = .097), lower reoperation incidence (2.0% vs 9.7%, P = .0098), and lower AI grade >2 recurrence (1.9% vs 11.2%, P = .0042), compared with patients with a Dacron ring. Mixed-effect model showed that with extra-aortic ring annuloplasty, annular dilation over time (P = .0033) was prevented and, compared with the homemade Dacron ring, root expansibility was better preserved (3.22% vs 2.12%, P = .002) and mean transvalvular gradient was lower (6.58 mm Hg vs 7.94 mm Hg, P = .001). Tricuspid and bicuspid valves with extra-aortic ring had similar reoperation (4.3% vs 0.85%, P = .65) and AI grade >2 incidence (2.7% vs 1.2%, P = .61), expansibility (P = .29), and diameter (P = .47), whereas mean transvalvular gradient was lower for tricuspid valves (5.58 mm Hg vs 7.60 mm Hg, P = .004).

CONCLUSIONS

Valve-sparing root remodeling with calibrated expansible extra-aortic ring annuloplasty improves the outcomes of reoperation and recurrent AI compared with a homemade Dacron ring. It prevents dilation and maintains physiological root dynamics for durable valve repair.

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

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.

Comparison of the Dacron ring and suture annuloplasty for aortic root repair: an in vitro evaluation

OBJECTIVES

Increasing evidence shows that annular stabilization is essential in most aortic valve repair procedures. However, a standardized comparison of the 2 commonly used annuloplasty procedures is lacking. We hypothesized that the Dacron ring is more rigid than the polytetrafluoroethylene suture, whereas both procedures decrease annular dimensions. The aim of this study was to compare the biomechanical properties of the ring and suture techniques with native aortic roots in vitro.

METHODS

Eighteen aortic roots explanted from 80-kg pigs were randomized into a Dacron ring group, a suture annuloplasty group and a native control group. Each sample was tested in a pulsatile in vitro model with a force transducer attached to the aortic annulus to obtain radial force measurements, and annular dynamics was evaluated using 2-dimensional echography.

RESULTS

Among the 2 annuloplasty procedures, only the Dacron ring group provided a significant reduction in the annular diameter compared with the native group (P < 0.006). Both annuloplasty procedures significantly reduced the geometric orifice area, tenting area and sinus diameter while increasing the coaptation length compared with the native group. Systolic annular distension was retained between groups, although the total radial forces were significantly reduced in the procedure groups compared with the native group (ring 1.07 ± 0.45 N, suture 1.13 ± 0.39 N and native 3.55 ± 1.34 N, P < 0.001).

CONCLUSIONS

Although both annuloplasty procedures increase coaptation length and decrease geometric orifice area, a significant downsizing of the annulus was achieved using the Dacron ring only. The systolic annular distension was similar to the native aortic root, whereas the radial annular forces were evenly decreased by both annuloplasty procedures. Long-term studies are needed to disclose any difference in long-term effect of the annuloplasty procedures.

Aortic valve repair for aortic regurgitation and preoperative echocardiographic assessment

Aortic valvuloplasty (AVP) has been performed less frequently than mitral valvuloplasty. The survival benefit of AVP over replacement has been demonstrated. Therefore, standardization of AVP is crucial for its widespread adoption. The hemodynamic advantage of AVP of preserving the native aortic valve may be one reason for the survival benefit. Recent guidelines still recommend AVP in selected cases compared with the less restricted recommendation for mitral valvuloplasty, although recent studies have proposed earlier indication for surgical intervention. Indication for aortic root replacement is also still conservative, especially in Japan. However, more liberal root replacement should be recommended for better repair when AVP is indicated. Theoretically, all aortic regurgitation lesions can be repaired with acceptable durability. However, restricted cusp should be extended by a pericardial patch, which itself has emerged as a risk of recurrence. Therefore, indications for aortic regurgitation for type III lesions should be determined carefully. Special consideration is crucial for bicuspid aortic valve repair; prevention of postoperative stenosis is especially important. Arrangement of the commissure position is the most important consideration for this purpose, although it remains controversial. Therefore, detailed diagnosis is important in planning AVP, and echocardiography plays a key role in this process.

Aortic Valvuloplasty or Rootplasty for Aortic Regurgitation

At present, aortic valvuloplasty is considered an effective procedure for treatment of aortic regurgitation in pediatric patients. It has encouraging mid- and long-term results. The improved outcome is primarily related to better understanding of the functional anatomy of the normal valve and the different factors that alter it. It is also related to the realization that outcome after valvuloplasty is dependent on comprehensive repair of all of the involved components of the aortic root. Refinement in preoperative diagnosis has helped identify these abnormal components and focus the surgical approach on the needed reconstruction. Although the technical aspects of valvuloplasty are well defined, suboptimal long-term results still occur in some cases because the patch material used for valve repair can become fibrotic or calcified. This review summarizes the surgical approach to and the management of the different abnormal root components in pediatric patients with significant aortic valve regurgitation.

Anatomy of the aortic root: implications for aortic root reconstruction

Since the introduction of valve-preserving root replacement and aortic annuloplasty, precise understanding of the aortic root anatomy has emerged as a key to successful aortic valve-preservation surgery. Fundamentally, surgeons need to know the precise anatomical definition and structure of the aortic root, including its normal dimensions, know the anatomy of the coronary arteries, and understand the cardiac conduction system. Surgeons must be able to clearly distinguish normal and abnormal structures, and recognize the effects of aortic valve regurgitation or root expansion on dimensions and geometric relationships within the aortic root. Possessing a detailed understanding of the aortic root, surgeons can select appropriately sized grafts and achieve optimum annular fixation. This review covers the essentials of aortic root anatomy and provides tips for correct and safe performance of aortic valve-preservation surgery with a view toward durable late outcomes.