Annular management during aortic valve repair: a systematic review

Adjustable external Dacron annuloplasty in aortic valve repair

In aortic valve repair, whilst performing a Yacoub remodelling operation, the external annuloplasty of the aortic ring plays a very important role. Here we present an adjustable external Dacron annuloplasty as an additional tool, in very selected cases, that can help surgeons to further improve their immediate results thus influencing the long-term ones.

Current controversies in aortic valve-preserving surgery

The clinical outcome of severe aortic regurgitation (AR) remains suboptimal, but surgery has been shown to have survival benefit over medical therapy. Postoperative survival is inferior in patients with reduced left ventricular function, and therefore early surgical intervention is recommended. Aortic valvuloplasty (AVP) is an attractive option to avoid the major drawbacks of prosthetic valves but has not been widely adopted. The etiology of AR is classified functionally into three groups: normal leaflet motion (type I), cusp prolapse (type II), and restriction (type III). Type I with dilatation of the sinus of Valsalva (type Ib) can be repaired by aortic valve reimplantation or aortic root remodeling with similar valve stability. Type I with dilatation of the aortic annulus (type Ic) can be managed by annuloplasty. Type II can be corrected by plication or resuspension techniques. Pericardial patch is necessary in AVP for type Id (perforation/fenestration) and type III but is associated with risk of recurrence. Bicuspid aortic valve is classified according to commissure angle: symmetrical, asymmetrical, and very asymmetrical. Tricuspidization is recommended for repair of very asymmetrical valves to avoid postoperative stenosis. Recent progress has achieved similar reoperation rates between bicuspid and tricuspid aortic valve repair. For Marfan syndrome, valve-sparing root replacement is advantageous compared to Bentall operation regarding late survival, thromboembolic and hemorrhagic events, and endocarditis. Similar findings have been reported in acute aortic dissection. Both remodeling and reimplantation procedures provide similar favorable outcomes in these settings. Recent advances in AVP are summarized by quantitative assessment of cusp configuration (effective height and geometric height), graft size decision, use of template to cut the graft, and videoscopic assessment of post-repair cusp configuration. Due to these advances, AVP shows superior results to replacement surgery. Further concrete evidence with larger case volumes and longer observation periods are necessary to popularize AVP.

Use of cardiac magnetic resonance imaging and cardiac magnetic resonance feature-tracking strain analysis to characterize and differentiate aortic annular strain patterns in aortic valve regurgitation versus normal aortic valves

BACKGROUND

Understanding the aortic annulus is important for obtaining reproducible and durable aortic valve (AV) repair and allowing advances for transcatheter AV replacement treatment of aortic regurgitation (AR). Significant limitations exist when using echocardiography and computed tomography-based imaging with feature tracking at the aortic annulus.

AIMS

Cardiac magnetic resonance is used to obtain regional longitudinal strain and can be modified to obtain circumferential annular strain at the fibrous and muscular portions of the AV annulus.

MATERIALS AND METHODS

Holst et al. use a novel method to characterize and prove that adverse annular deformation occurs at the muscular portion of the AV annulus in patients with AR. In their study, cardiovascular magnetic resonance (CMR) imaging and CMR feature-tracking strain analysis are used to characterize aortic annular regional longitudinal strain (RLS) in humans.

RESULTS

The authors convincing show that the direction of muscular annular deformation in patients with AR is opposite to the direction of muscular annular deformation in patients with normal Avs, (median RLS: 4.18% in patients with severe AR vs. -10.41% in well-functioning AVs, p = .024; at RLS muscular annulus).

DISCUSSION AND CONCLUSION

The direction of muscular annular deformation in patients with AR is opposite to the direction of muscular annular deformation in patients with normal AVs. This information will have impactful physiological relevance for surgical and percutaneous treatment of aortic valve pathology.

Early results after aortic annuloplasty with a complete external Dacron band

OBJECTIVE

This study evaluates the early results of our initial experience with aortic annuloplasty using a complete external Dacron band in the setting of type Ic or type II aortic regurgitation (AR).

METHODS

From May 2017 to August 2019, 16 patients (88% bicuspid aortic valves, no patients with connective tissue disorders) underwent aortic annuloplasty with an external complete Dacron band. Clinical and echocardiographic follow-up was 100% complete. Clinical and echocardiographic follow-up averaged 24.4 ± 9.3 and  15.1 ±  8.3 months, respectively.

RESULTS

Mean cardiopulmonary and cross-clamp times were 105 ± 15 (72-127) and 86 ± 15 (51-113) min, respectively. Early and late mortality was 0%, with no incidents of endocarditis or cerebrovascular events during the follow-up. Two patients were re-operated during the follow-up, one due recurrent aortic regurgitation (12 months after the first operation) yielding a freedom from reoperation due to AR at 1 year and 3 years of 100% ± 0% and 93.3% ± 5.7%, respectively. Based on the latest echocardiogram, five patients had either none or trivial AR, six had mild AR, and three had mild-to-moderate AR.

CONCLUSIONS

The early clinical and echocardiographic results after using a complete external Dacron band are promising; however, more data and longer follow-up are needed to determine its role in annular management during aortic valve repair.

Aortic Valve Repair in Annular Dilatation: External Versus Internal Suture Annuloplasty

BACKGROUND

Annuloplasty is essential in aortic valve repair. The most appropriate technique is, however, highly controversial. We aimed to evaluate changes in postoperative annulus diameter on serial echocardiography after external and internal suture annuloplasty.

METHODS

We retrospectively reviewed serial transthoracic echocardiography of consecutive patients from our institutional aortic valve repair registry who had received suture annuloplasty. Mid-systolic annulus diameter was measured on parasternal long-axis view preoperatively, at discharge, 3-6 months, 1, 2 and 3 years postoperatively. Primary endpoint was the prevalence of annulus re-dilatation. Secondary endpoints were the correlation between annulus re-dilatation and (1) external vs. internal technique and (2) reoccurrence of aortic insufficiency (AI)≥2.

RESULTS

A total of 70 patients (mean age 43±13 years, 91% male) underwent aortic valve repair including external (n=27) or internal (n=43) suture annuloplasty between February 2016 and November 2019. Mean follow-up was 17±11 (3-50) months. Mean preoperative annulus diameter of 29.7±2.8 (23.8-37.8) mm was significantly reduced to 22.7±2.9 (16.7-31.7) mm, p<0.001 at discharge and increased to 23.8±2.3 (20.9-27.0) mm, p=0.037 during follow-up. The mild increase in postoperative annulus diameter did not correlate with the reoccurrence of AI≥2. Preoperative annulus was significantly larger in the external group (external: 30.6±3.2 mm; internal: 29.1±2.5 mm; p=0.032). However, we found no significant difference in postoperative annulus increase rate between both techniques.

CONCLUSIONS

Although mild, a significant continuous increase of annulus diameter after suture annuloplasty was seen which did not correlate with the reoccurrence of AI≥2 at mid-term follow-up. Annulus re-dilatation was comparable between external and internal technique.

Current trends in aortic valve-preserving surgery

The natural history of aortic regurgitation is not as benign as once believed, even in asymptomatic patients with preserved left ventricular function. Aortic valve surgery can prolong survival in these patients. However, both mechanical and biological aortic valve replacement have major disadvantages, especially in young patients. Aortic valve-preserving surgery has attracted a great deal of attention because it has a significant survival benefit over replacement. Nonetheless, aortic valve-preserving surgery has not been widely adopted due to the complexity of the technique and assessment (i.e., long learning curve). With recent technical and theoretical advances, aortic valve-preserving surgery has increasingly been performed with better outcomes, and therefore earlier surgical intervention in cases of aortic regurgitation has been considered. Recent advances in aortic valve-preserving surgery include repair-oriented classification of the etiology of aortic regurgitation, objective assessment of the cusp configuration (i.e., effective height and geometric height), use of aortic annuloplasty, introduction of two reproducible valve-sparing root replacement procedures (i.e., aortic valve reimplantation and aortic root remodeling techniques), standardization of aortic valve-preserving surgery, and assessment of cusp configuration with aortoscopy. A number of prospective multicenter studies are currently underway and will clarify the role of aortic valve-preserving surgery in the treatment of aortic regurgitation in the near future.

Aortic annulus and the importance of annuloplasty

Dystrophic aortic insufficiency accounts for the majority of Western cases of aortic insufficiency and can be divided into the three phenotypes of isolated aortic insufficiency, dilated aortic root, and dilated ascending aorta. Each of these phenotypes is associated with a dilated annulus and/or sinotubular junction. Recent international guidelines recommend reimplantation or remodeling with aortic annuloplasty for valve-sparing root replacement, as well as consideration of aortic valve repair in cases of aortic insufficiency. A dilated aortic annulus is a major risk factor for failure of aortic valve repair procedures, indicating the need to address the annulus at the time of aortic valve or root repair. Calibrated annuloplasty should be performed at sub- and supravalular levels in order to restore the ratio of the sinotubular junction and annulus and be adapted according to the phenotype of the root and ascending aorta. Standardization of aortic valve repair techniques with use of a calibrated annuloplasty will improve dissemination of techniques and rate of aortic valve repair. Current medical evidence shows that aortic valve repair is safe, produces better quality of life, and reduces valve-related mortality compared to prosthetic valve replacement.

Aortic root destruction after aortic valvuloplasty for bicuspid aortic valve

Ultrasound cardiography showed severe aortic regurgitation (AR) due to bicuspid aortic valve with dilatation of the aortic annulus and sinotubular junction in a 27-year-old man hospitalized with loss of consciousness. He underwent aortic valvuloplasty combined with external suture annuloplasty using an expanded polytetrafluoroethylene (ePTFE) suture. Intraoperative findings revealed thickening and adhesion of the aortic root despite the first surgery. He developed recurrent AR 7 months later and underwent redo surgery. An ePTFE suture was found inside the aorta. Aortic root replacement with a mechanical composite graft was performed, as reconstruction appeared difficult because the aortic annulus was damaged and there were multiple holes on all cusps. Here, we report a rare case of aortic root destruction after external suture annuloplasty.

Rationale for aortic annuloplasty to standardise aortic valve repair

Available evidence shows that aortic valve repair reduces valve-related mortality and improves quality of life compared to prosthetic aortic valve replacement. One of the most important predictors of bicuspid and tricuspid aortic valve repair failure is the absence of treating a dilated aortic annulus greater than 25-28 mm. Competency of the aortic valve depends on multiple factors including the diameter of the annulus, sinotubular junction, valve cusps and commissures. Dystrophic aortic insufficiency (AI) is the commonest cause of AI in the Western world and is characterised by dilatation of the aortic annulus (≥25 mm), sinuses and/or sinotubular junction (≥30 mm). Depending on whether the sinuses of Valsalva and/or tubular ascending aorta are dilated, three phenotypes can be identified: dilated aortic root, dilated ascending aorta and isolated AI. All three phenotypes are associated with a dilated aortic annulus. Aortic annuloplasty reduces the dilated aortic annulus and improves the surface of coaptation, as in the case of mitral valve repair. In treating AI, it is also important to restore the physiological sinotubular junction/annulus ratio, which can be carried out with remodeling root repair + subvalvular annuloplasty (for dilated aortic root), tubular ascending aorta replacement + subvalvular annuloplasty (for dilated ascending aorta) and double sub- and supra-valvular annuloplasty (for isolated AI). Aortic annuloplasty is now considered an essential component of aortic valve repair and valve-sparing root surgery.

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.