Surgical Anatomy of the Aortic Annulus: Landmarks for External Annuloplasty in Aortic Valve Repair

Thoracic Aorta: Anatomy and Pathology

The aorta is the largest elastic artery in the human body and is classically divided into two anatomical segments, the thoracic and the abdominal aorta, separated by the diaphragm. The thoracic aorta includes the aortic root, the ascending aorta, the arch, and the descending aorta. The aorta's elastic properties depend on its wall structure, composed of three distinct histologic layers: intima, media, and adventitia. The different aortic segments show different embryological and anatomical features, which account for their different physiological properties and impact the occurrence and natural history of congenital and acquired diseases that develop herein. Diseases of the thoracic aorta may present either as a chronic, often asymptomatic disorder or as acute life-threatening conditions, i.e., acute aortic syndromes, and are usually associated with states that increase wall stress and alter the structure of the aortic wall. This review aims to provide an update on the disease of the thoracic aorta, focusing on the morphological substrates and clinicopathological correlations. Information on anatomy and embryology will also be provided.

Valve Repair in Aortic Insufficiency: A State-of-the-art Review

Aortic valve insufficiency (AI) describes the pathology of blood leaking through the aortic valve to the left ventricle during diastole and is classified as mild, moderate or severe according to the volume of regurgitating blood. Intervention is required in severe AI when the patient is symptomatic or when the left ventricular function is impaired. Aortic valve replacement has been considered the gold standard for decades for these patients, but several repair techniques have recently emerged that offer exceptional stability and long-term outcomes. The appropriate method of repair is selected based on the mechanism of AI and each patient's anatomic variations. This review aims to describe different pathologies of AI based on its anatomy, along with the different surgical techniques of aortic repair and their reported results.

Aortic Valve Repair Using HAART 300 Geometric Annuloplasty Ring: A Review and Echocardiographic Case Series

Aortic valve repair (AVr) aims to preserve the native aortic leaflets and restore normal valve function. In doing so, AVr is a more technically challenging approach than traditional aortic valve replacement. Some of the complexity of repair techniques can be attributed to the unique structure of the functional aortic annulus (FAA), which, unlike the well-defined mitral annulus, is comprised of virtual and functional components. Though stabilizing the ventriculo-aortic junction (VAJ), a component of the FAA, is considered beneficial for patients with chronic aortic insufficiency (AI), the ideal AVr technique remains a subject of much debate. The existing AVr techniques do not completely stabilize the VAJ which may increase susceptibility to recurrent AI due to VAJ dilation. An emerging new technique showing promise for the treatment of both isolated and complex AI is AVr using HAART 300^TM geometric annuloplasty ring (GAR). The GAR is implanted below the valve leaflets in the left ventricular outflow tract (LVOT), providing stability and creating a neo-annulus. As with other AVr subtypes, this procedure has a learning curve. There are unique surgical and echocardiographic aspects of AVr with GAR, including the appearance of the LVOT, the aortic valve leaflets, and their motion which cardiac anesthesiologists and echocardiographers must be familiar with. In this work, using an eight-patient echocardiographic case series, we provide an overview of this novel AVr technique, including some unique aspects of device sizing, patient selection, expected post-repair echocardiographic features, and a review of outcomes data.

Understanding the Aortic Root Using Computed Tomographic Assessment: A Potential Pathway to Improved Customized Surgical Repair

There is continued interest in surgical repair of both the congenitally malformed aortic valve, and the valve with acquired dysfunction. Aortic valvar repair based on a geometric approach has demonstrated improved durability and outcomes. Such an approach requires a thorough comprehension of the complex 3-dimensional anatomy of both the normal and congenitally malformed aortic root. In this review, we provide an understanding of this anatomy based on the features that can accurately be revealed by contrast-enhanced computed tomographic imaging. We highlight the complimentary role that such imaging, with multiplanar reformatting and 3-dimensional reconstructions, can play in selection of patients, and subsequent presurgical planning for valvar repair. The technique compliments other established techniques for perioperative imaging, with echocardiography maintaining its central role in assessment, and enhances direct surgical evaluation. This additive morphological and functional information holds the potential for improving selection of patients, surgical planning, subsequent surgical repair, and hopefully the subsequent outcomes.

International Consensus Statement on Nomenclature and Classification of the Congenital Bicuspid Aortic Valve and Its Aortopathy, for Clinical, Surgical, Interventional and Research Purposes

This International Consensus Classification and Nomenclature for the congenital bicuspid aortic valve condition recognizes 3 types of bicuspid valves: 1. The fused type (right-left cusp fusion, right-non-coronary cusp fusion and left-non-coronary cusp fusion phenotypes); 2. The 2-sinus type (latero-lateral and antero-posterior phenotypes); and 3. The partial-fusion (forme fruste) type. The presence of raphe and the symmetry of the fused type phenotypes are critical aspects to describe. The International Consensus also recognizes 3 types of bicuspid valve-associated aortopathy: 1. The ascending phenotype; 2. The root phenotype; and 3. Extended phenotypes. ©  2021 Jointly between the RSNA, the European Association for Cardio-Thoracic Surgery, The Society of Thoracic Surgeons, and the American Association for Thoracic Surgery. The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. All rights reserved. Keywords: Bicuspid Aortic Valve, Aortopathy, Nomenclature, Classification.

Summary: international consensus statement on nomenclature and classification of the congenital bicuspid aortic valve and its aortopathy, for clinical, surgical, interventional and research purposes

This International evidence-based nomenclature and classification consensus on the congenital bicuspid aortic valve and its aortopathy recognizes 3 types of bicuspid aortic valve: 1. Fused type, with 3 phenotypes: right-left cusp fusion, right-non cusp fusion and left-non cusp fusion; 2. 2-sinus type with 2 phenotypes: Latero-lateral and antero-posterior; and 3. Partial-fusion or forme fruste. This consensus recognizes 3 bicuspid-aortopathy types: 1. Ascending phenotype; root phenotype; and 3. extended phenotypes.

International consensus statement on nomenclature and classification of the congenital bicuspid aortic valve and its aortopathy, for clinical, surgical, interventional and research purposes

This International Consensus Classification and Nomenclature for the congenital bicuspid aortic valve condition recognizes 3 types of bicuspid valves: 1. The fused type (right-left cusp fusion, right-non-coronary cusp fusion and left-non-coronary cusp fusion phenotypes); 2. The 2-sinus type (latero-lateral and antero-posterior phenotypes); and 3. The partial-fusion (forme fruste) type. The presence of raphe and the symmetry of the fused type phenotypes are critical aspects to describe. The International Consensus also recognizes 3 types of bicuspid valve-associated aortopathy: 1. The ascending phenotype; 2. The root phenotype; and 3. Extended phenotypes.

Summary: International consensus statement on nomenclature and classification of the congenital bicuspid aortic valve and its aortopathy, for clinical, surgical, interventional, and research purposes

This International evidence-based nomenclature and classification consensus on the congenital bicuspid aortic valve and its aortopathy recognizes 3 types of bicuspid aortic valve: 1. Fused type, with 3 phenotypes: right-left cusp fusion, right-non cusp fusion and left-non cusp fusion; 2. 2-sinus type with 2 phenotypes: Latero-lateral and antero-posterior; and 3. Partial-fusion or forme fruste. This consensus recognizes 3 bicuspid-aortopathy types: 1. Ascending phenotype; root phenotype; and 3. extended phenotypes.

International consensus statement on nomenclature and classification of the congenital bicuspid aortic valve and its aortopathy, for clinical, surgical, interventional and research purposes

This International Consensus Classification and Nomenclature for the congenital bicuspid aortic valve condition recognizes 3 types of bicuspid valves: 1. The fused type (right-left cusp fusion, right-non-coronary cusp fusion and left-non-coronary cusp fusion phenotypes); 2. The 2-sinus type (latero-lateral and antero-posterior phenotypes); and 3. The partial-fusion (forme fruste) type. The presence of raphe and the symmetry of the fused type phenotypes are critical aspects to describe. The International Consensus also recognizes 3 types of bicuspid valve-associated aortopathy: 1. The ascending phenotype; 2. The root phenotype; and 3. Extended phenotypes.

Summary: International Consensus Statement on Nomenclature and Classification of the Congenital Bicuspid Aortic Valve and Its Aortopathy, for Clinical, Surgical, Interventional and Research Purposes

This International evidence-based nomenclature and classification consensus on the congenital bicuspid aortic valve and its aortopathy recognizes 3 types of bicuspid aortic valve: 1. Fused type, with 3 phenotypes: right-left cusp fusion, right-non cusp fusion and left-non cusp fusion; 2. 2-sinus type with 2 phenotypes: Latero-lateral and antero-posterior; and 3. Partial-fusion or forme fruste. This consensus recognizes 3 bicuspid-aortopathy types: 1. Ascending phenotype; root phenotype; and 3. extended phenotypes.

International Consensus Statement on Nomenclature and Classification of the Congenital Bicuspid Aortic Valve and Its Aortopathy, for Clinical, Surgical, Interventional and Research Purposes

This International Consensus Classification and Nomenclature for the congenital bicuspid aortic valve condition recognizes 3 types of bicuspid valves: 1. The fused type (right-left cusp fusion, right-non-coronary cusp fusion and left-non-coronary cusp fusion phenotypes); 2. The 2-sinus type (latero-lateral and antero-posterior phenotypes); and 3. The partial-fusion (forme fruste) type. The presence of raphe and the symmetry of the fused type phenotypes are critical aspects to describe. The International Consensus also recognizes 3 types of bicuspid valve-associated aortopathy: 1. The ascending phenotype; 2. The root phenotype; and 3. Extended phenotypes.

Free margin length and geometric height in aortic root dilatation and leaflet prolapse: implications for aortic valve repair surgery

OBJECTIVES

Our goal was to assess the aortic leaflet free margin length (FML) and geometric height (gH) in a normal aortic valve (AV), aorta dilatation and aortic leaflet prolapse.

METHODS

We measured the FML and gH intraoperatively in 132 patients operated on for aortic insufficiency, aortic dilatation, endocarditis or fibroelastoma. Patients were divided into 3 groups: normal tricuspid AV (group 1, n = 12), aortic dilatation (group 2, tricuspid = 43, bicuspid = 18) and leaflet prolapse (group 3, tricuspid = 32, bicuspid = 27). The FML and gH were compared between the groups and between the leaflets within each group.

RESULTS

In a normal tricuspid AV, the mean FML and gH were 34.7 ± 3.1 mm and 18.8 ± 1.7 mm, respectively. In group 2 tricuspid, the FML and gH were greater than those in group 1 (FML 43.7 ± 4.4, P < 0.001; gH 21.2 ± 1.8, P = 0.003). In group 3, tricuspid, the FML of the prolapsing leaflet was greater than the FML of the non-prolapsing leaflet (48.3 ± 5.4 vs 42.2 ± 3.6; P < 0.001). In group 2, bicuspid, FML of both leaflets were similar in group 2, but augmented on the fused leaflet compared to the non-fused leaflet in group 3 (fused 55.4 ± 6.3; non-fused 46.2 ± 6.2; P < 0.001). In groups 2 and 3 bicuspid, the gH of the non-fused leaflet was systematically greater than the fused leaflet (group 2 non-fused 24.6 ± 2.5 vs fused 20.4 ± 2.1; P < 0.001).

CONCLUSIONS

In aortic dilatation and leaflet prolapse, FML and, to a lesser extent, gH increased significantly compared to those of normal AV function. FML and gH dimensions also depended on the valve configuration (tricuspid/bicuspid). These data provide new insight into the pathomorphology of AV disease and will serve to further develop new methods of AV repair based on intraoperative measurements of the FML.

Normative Aortic Valvar Measurements in Adults Using Cardiac Computed Tomography - A Potential Guide to Further Sophisticate Aortic Valve-Sparing Surgery

BACKGROUND

A thorough understanding of the anatomy of the aortic valve is necessary for aortic valve-sparing surgery. Normal valvar dimensions and their relationships in the living heart, however, have yet to be fully investigated in a 3-dimensional fashion.Methods and Results:In total, 123 consecutive patients (66±12 years, Men 63%) who underwent coronary computed tomographic angiography were enrolled. Mid-diastolic morphology of the aortic roots, including height of the interleaflet triangles, geometric height, free margin length of each leaflet, effective height, and coaptation length were measured using multiplanar reconstruction images. Average height of the interleaflet triangle, geometric height, free margin length, effective height, and the coaptation length were 17.3±1.8, 14.7±1.3, 32.6±3.6, 8.6±1.4, and 3.2±0.8 mm, respectively. The right coronary aortic leaflet displayed the longest free margin length and shortest geometric height. Geometric height, free margin length, and effective height showed positive correlations with aortic root dimensions. Coaptation length, however, remained constant regardless of aortic root dimensions.

CONCLUSIONS

Diversities, as well as characteristic relationships among each value involving the aortic root, were identified using living-heart datasets. The aortic leaflets demonstrated compensatory elongation along with aortic root dilatation to maintain constant coaptation length. These measurements will serve as the standard value for revealing the underlying mechanism of aortic regurgitation to plan optimal aortic valve-sparing surgery.

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.

Is small cusp size a limitation for aortic valve repair?†

OBJECTIVES

We sought to investigate cusp size limitations for valve repair in patients with aortic regurgitation (AR).

METHODS

Preoperative computed tomography was performed in 105 patients. Cusp geometric height (GH) and annulus size were measured. Mean patient age was 60.7 ± 13.7 years. Mean GH of 3 cusps was used in the analysis. Annulus cusp mismatch was graded using predicted coaptation length. Patients were categorized by mean GH into group S (GH <16 mm; n = 35) or L (GH ≥16 mm; n = 70).

RESULTS

Preoperative mean GH was 17.1 ± 2.3 mm. GH and body height were significantly correlated (r = 0.61). Intraoperative mean GH (18.8 ± 2.2 mm) was larger than preoperative mean GH (P < 0.0001). However, postoperative (17.1 ± 2.0 mm) and preoperative mean GH did not differ. Moderate AR was not present on predischarge echocardiography. Mild AR was observed in 51% and 17% of patients in groups S and L, respectively (P = 0.006). During follow-up, moderate or severe AR was observed in 14% and 10% of patients in groups S and L, respectively (P = 0.74). Two patients in group S required reoperation for a regurgitant valve. Twenty (83%) and 15 (21%) patients in groups S and L, respectively, had severe annulus cusp mismatch before surgery. Annulus cusp mismatch resolved in most patients in group L postoperatively, whereas more than half the patients in group S still had severe mismatch.

CONCLUSIONS

Small cusp size (GH <16 mm) is not necessarily a contraindication in aortic valve repair. However, most patients in this group had annulus cusp mismatch. Root replacement or secure annulus plication is mandatory to correct annulus cusp mismatch.

Inter-operative determination of the aortic root and cusp geometry associated with the aortic regurgitation grade

PURPOSES

To perform successful aortic valve plasty (AVP) and valve-sparing root replacement (VSRR), a sufficient understanding of the aortic root and cusp geometry is required. Several key parameters of the aortic root and cusp geometry were, therefore, measured intraoperatively.

METHODS

Forty-nine patients (63.1 ± 16.6 y.o., 40 males) were measured during the surgeries. The patients were divided into 3 groups; including patients with no or mild aortic valve regurgitation (AR) (n = 13), moderate AR (n = 18), and severe AR (n = 18).

RESULTS

There were no significant differences in the body surface area (1.72 ± 0.19 m²) among the 3 groups (p = 0.858). The effective height (EH) and geometric height (GH) of right coronary cusp were smaller than those of the others (EH: p = 0.068, GH: p < 0.01). The insertion line length (ILL) and free margin length (FML) of each leaflet tended to be significantly longer according to the AR grade(ILL: p < 0.01, FML: p < 0.01). The FML/AVJ ratios were significantly different (p < 0.01). The FML/ILL ratios were constant with the ratio of 0.88 ± 0.1(p = 0.624).

CONCLUSIONS

Although the ILL and FML tended to increase with the AR grade, the FML/ILL ratio remained constant. For successful AVP and VSRR, adequately maintaining the FML/ILL ratio is necessary to prevent remarkable cusp prolapse while also preserving its favorable cusp motion.

State-of-the art bicuspid aortic valve repair in 2020

Patients with a bicuspid aortic valve (BAV) frequently require surgical intervention for aortic regurgitation (AR) and/or aneurysm. Valve-preserving surgery and repair of regurgitant BAVs have evolved into an increasingly used alternative to replacement. Anatomic predictors of possible repair failures have been identified and solutions developed. Using current techniques most non-calcified BAVs can be preserved or repaired. Excellent repair durability and freedom from valve-related complications can be achieved if all pathologic components of aortic valve and root including annular dilatation are corrected. Anatomic variations must be addressed using tailored approaches.

Focus on the annuloplasty in aortic valve repair: implications from a quantitative multislice computed tomography analysis

Background

Aortic valve (AV) repair has evolved towards a treatment alternative in young patients with AV regurgitation and was accompanied by the development of surgical repair strategies. An efficient and reproducible AV annulus stabilization (i.e., annuloplasty) has been proposed as a crucial component to obtain the long-term stability of AV repair. However, there is still major controversy regarding the most appropriate annuloplasty approach. We aimed to address AV annulus structures which are relevant for AV annuloplasty, based on MS-CT data.

Methods

We retrospectively analysed 326 consecutive patients with AV disease who all underwent preprocedural MS-CT examination. Study cohort was subdivided according to the underlying AV pathology: 25 patients with aortic regurgitation (AR subgroup) (mean age 73±11 years, 68% male), 243 patients with aortic stenosis (AS subgroup) (73±11 years, 68% male) and 58 patients with normally functioning AV (normal AV subgroup) (mean age 76±7 years, 36% male). We systematically measured maximum and minimum AV annulus diameter, AV annular area, projected AV annular perimeter and anatomic AV annular perimeter during mid-systole using MS-CT data. Based on these measurements, AV annular eccentricity index was calculated [(max AV annulus × 100/min AV annulus) - 100]. Furthermore, we assessed the tissue components of AV annular plane, distinguishing between muscular and fibrous portions of the basal ring.

Results

AV annular eccentricity index was significantly larger in the normal AV-subgroup as compared to the AR-subgroup (33.2%±10.7% vs. 27.8%±9.2%; P=0.048) as well as to the AS-subgroup (33.2%±10.7% vs. 20.4%±8.8%; P<0.001). AV annular area was significantly larger in the AR subgroup as compared to the AS subgroup (5.7±1.0 vs. 5.1±0.8 cm²; P=0.003) and normal AV subgroup (5.7±1.0 vs. 4.8±0.8 cm²; P<0.001). Intramuscular plane in the right coronary sinus was significantly increased in the AR subgroup vs. AS subgroup (12.8±2.7 vs. 7.5±3.6 mm; P<0.001) and normal AV subgroup (12.8±2.7 vs. 8.7±3.0 mm; P<0.001). Muscular component of the basal ring was significantly reduced in the AR subgroup vs. AS subgroup (37.5%±5.1% vs. 40.5%±5.5%; P=0.039) and normal AV subgroup (37.5%±5.1% vs. 44.3%±10.2%; P=0.001).

Conclusions

MS-CT enables a quantitative analysis of aortic root anatomy which may have an impact on AV annuloplasty. AR patients differ significantly regarding their AV annular dimensions and basal ring morphology as compared to the AS patients and those with a normal AV function. These findings may have major implications in tricuspid AV repair when designing the most appropriate AV annulus stabilisation technique.

The aortic root hexagon as an aide memoire to the important surgical landmarks

BACKGROUND

The anatomy of the aortic root and its relationship to cardiac landmarks is important for valve-sparing surgery and understanding the pathology of lesions arising in this structure. Rapid understanding of the key anatomical details can be achieved by a geometrical concept based on the shape of a hexagon.

METHODS

Definitions, structure, and key anatomical concepts of the aortic root according to the current literature were reviewed. Thirty pig hearts were dissected to explore the relationships of the six points on the aortic root. Six double 2/0 ethibond needles were placed into the six points at 90°. The passage of the needles through the specific cardiac landmarks at each point was noted. The aortic root hexagon is a geometrical structure formed by two triangles superimposed on each other. The six points in the hexagon relate to important adjacent cardiac landmarks.

RESULTS

The two best-known anatomical relationships are of the left-non coronary aortic commissure to the longitudinal axis of symmetry of the aortic leaflet of the mitral valve and the relationship of the nadir of the noncoronary aortic valve leaflet to the medial commissure of the mitral valve. The other four points are related to equally significant and well defined anatomical landmarks.

CONCLUSION

The aortic root hexagon is made by two triangles superimposed on each other, these are the commissural and nadir triangles respectively. We have found this concept to be a quick way to learn and remember the key anatomical relationships of the aortic root.

Predictors of Aortic Valve Repair Failure

Aortic valve repair is the preferred approach for the treatment of severe aortic insufficiency (AI), as it allows patients to keep their native aortic valve, thus substantially reducing the risk of prosthesis-related complications. Several studies have documented excellent long-term outcomes of aortic valve repair. The major complication of this operation is AI recurrence, with ensuingneed for reoperation. The surgical experience accumulated over the last two decades has allowed for better understanding of the mechanisms of recurrent AI after aortic valve repair. Herein, we review the current state of knowledge on predictors of aortic valve repair failure. These include unaddressed annular dilation, residual cusp prolapse or retraction, commissural orientation, and use of patch material. This enhanced understanding has led to the development of increasingly refined techniques and improved patient outcomes. Continued follow-up and detailed data collection at the time of surgery, together with three-dimensional echo imaging, will allow further improvements in aortic valve repair.

Surgical anatomy of the aortic valve and root-implications for valve repair

The aortic root is an important anatomical structure positioned at the center of the heart, making it critical to the functioning of the major cardiac chambers. Deep knowledge of the anatomical "surroundings" of the aortic root is crucial for surgeon attempting to spare or repair a leaking aortic valve. In fact, root dissection is a necessary step to "skeletonize" the aortic valve, allowing the surgeon to work on the critical components of its structure, namely the aorto-ventricular junction, the virtual basal ring (VBR) and the sino-tubular junction (STJ). These three components, along with the insertion of the leaflet to the aortic wall, form the skeleton of the aortic valve that is essential in guaranteeing valve competence. A good anatomical proportion between the various component of the skeleton of the aortic valve need to be verified, or re-established in order to set the basis for an optimal aortic valve repair. Once the skeleton of the heart has been correctly addressed, the condition of the valve leaflets need to be considered. Excess of leaflet tissue is treated by leaflet plication or resection and lack of leaflet tissue is addressed by tissue extension with autologous or heterologous materials. In the present manuscript, we highlight the principal structure of the aortic root and describe in detail each anatomical component. This basic anatomical knowledge is also important for a through understanding of the normal function of the valve and root structure during the cardiac cycle. The close boundaries existing between the left ventricular cavity and the aorta are important in explaining the sophisticated function of opening and closing of the aortic valve. Similarly, the role played by the sinuses of Valsalva in regulating the blood flow exiting the ventricle underline the concept that "form follows function" and emphasizes the importance of a good anatomical reconstruction for an optimal and long-lasting valve function.

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.

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.

Geometry of cusp and root determines aortic valve function

The aortic valve is the functional unit of cusp and root. Various geometrical and functional analyses for the aortic valve unit have been executed to understand normal valve configuration and improve aortic valve repair. Different concepts and procedures have then been proposed for reparative approach, and aortic valve repair is still not standardized like mitral valve repair. It has become apparent, however, that interpretation of the geometry of the aortic cusp and root and its appropriate application to operative strategy lead to creating a functioning aortic valve. Herein, the aortic valve geometry and its clinical implications are reviewed to provide information for the selection of appropriate operative strategies.

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.

In Vivo Biocompatibility of a Novel Expanded Polytetrafluoroethylene Suture for Annuloplasty

BACKGROUND

Expanded polytetrafluoroethylene (ePTFE) is a suture material for annuloplasty in aortic valve repair. For this particular application, it should induce minimal local stress and promote rapid tissue incorporation. To achieve this, a novel ePTFE suture with a larger diameter and high porosity in its midsection has been developed. Herein, we analyzed the acute and chronic tissue reaction to this suture material compared with a commercially available control ePTFE suture.

METHODS

Novel and control suture samples were implanted into dorsal skinfold chambers of BALB/c mice to analyze the early inflammatory response using intravital fluorescence microscopy over 14 days. Additional suture samples were implanted for 4 and 12 weeks in the flank musculature of mice and analyzed by histology and immunohistochemistry.

RESULTS

The implantation of novel and control ePTFE suture into the dorsal skinfold chamber did not induce an acute inflammation, as indicated by physiological numbers of rolling and adherent leukocytes in all analyzed venules. Chronic implantation into the flank musculature showed a better tissue incorporation of the novel ePTFE suture with more infiltrating cells and a higher content of Sirius red+ collagen fibers when compared with controls. Cell proliferation and viability as well as numbers of recruited CD68+ macrophages, myeloperoxidase+ neutrophilic granulocytes and CD3+ lymphocytes did not significantly differ between the groups.

CONCLUSION

The novel ePTFE suture exhibits a good in vivo biocompatibility which is comparable to that of the control suture. Due to its improved tissue incorporation, it may provide a better long-term stability during annuloplasty.

Aortic valve repair

PURPOSE OF REVIEW

Recently, there has been a renewed interest with regard to surgical strategies for aortic valve preservation in the presence of isolated valve disease or concomitant aortic root disease, despite concerns having been raised about the mid/long-term durability of such repair techniques for the aortic valve. The aim of the present review is to analyze the currently available evidence about aortic valve repair strategies, for either bicuspid or tricuspid valves.

RECENT FINDINGS

An improved understanding of the surgical anatomy and functional analysis of the aortic valve and root has allowed a systematic classification for the mechanisms of aortic valve insufficiency. Similarly, the use of dedicated instruments and devices has led to improved outcomes in terms of not only long-term survival but also freedom from reoperation.

SUMMARY

Aortic valve repair, either as a stand-alone procedure or especially in combination with surgery of the root, is a well-tolerated and effective procedure with excellent outcomes at mid/long term. Recent efforts allowed the refinement of surgical techniques to develop a systematic approach to aortic valve repair, which implies a thorough understanding of the surgical anatomy, the functional causes of disease, and the available repair techniques along with their potential limitations. A specialized team including dedicated surgeons and cardiologists appears to be crucial to achieve durable and satisfactory outcomes following aortic valve repair.

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.

Aortic Valve Repair of a Stenotic Unicuspid Aortic Valve in Young Patients

BACKGROUND

The unicuspid aortic valve (UAV) is a well-described pediatric congenital abnormality, with incidence of 0.02% in the general population. Bicuspidization has been described as a potential surgical option to repair this defect.

METHODS

Seventeen symptomatic young patients with a unicuspid valve combined with either valve insufficiency or valve stenosis underwent aortic valve (AV) bicuspidization procedure by using an equine pericardium. In addition to bicuspidization, 8 patients underwent aortic ring implantation and 5 patients underwent supracoronary replacement of the aorta.

RESULTS

Our results show safety of the bicuspidization procedure. No deaths occurred during our average follow-up period of 26 months. Freedom from reoperation for any valve-related reason was 100% during this follow-up period. We observed a statistically significant increase in the AV area from 0.8 ± 0.1 cm² to 2.8 ± 0.7 cm² (p < 0.01), a statistically significant decrease in the mean systolic pressure gradient from 36 ± 13.3 mm Hg to 9 ± 4 mm Hg (p < 0.001), a statistically significant decrease in aortic insufficiency grade from 2.1 ± 1.0 to 0.6 ± 0.7 (p < 0.01) before and after bicuspidization, respectively, and a statistically significant decrease in the left ventricular end-diastolic diameter from 49.88 ± 5.11 mm to 40.46 ± 7.20 mm (p < 0.0005) and a statistically significant increase of the left ventricular ejection fraction from 56% ± 8.20% to 64% ± 7.83% at the time of follow-up.

CONCLUSIONS

From our study, bicuspidization is an attractive surgical option to repair UAV, particularly in young patients who do not want to be subjected to long-term anticoagulation therapy or who refuse a more traditional surgical approach, such as Ross procedure, for reasons described previously.

The optimal shape of an aortic heart valve replacement – on the road to the consensus

The steady increase in the number of patients with diseased aortic valves demands the development of effective aortic valve replacement procedures. Engineering and technology offer various manufactured alternatives, but none can exactly match the natural human valve. In addition to the experts of heart valve tissue engineering, many researchers focus on specific aspects of the manufacturing of artificial valves. The aim of this study was to benefit such manufacturing processes. From the contributor's perspective, it is vital to gain comprehensive knowledge before embarking on this project. The perfect/optimal shape of the valve is the fundamental aspect that needs to be considered by all participants. It is noteworthy that the geometry not only limits the functionality of the structure but also determines the choice of material and engineering methods. In this study, we attempt to determine if current knowledge is sufficient to reach consensus on the issue of the optimum shape of the valve. Here, we not only provide a brief overview of traditional literature but also include the opinions of experts. This innovative way of scientific communication is unprecedented in scientific literature, and we hope that both professionals and contributors will find this study useful.

Aortic valve sparing root surgery for Marfan syndrome

Aortic valve sparing root surgery (AVSRS) is a safe and durable alternative for patients with dilated roots or pure aortic regurgitation (AR), which avoids the risks of anticoagulation or valvular degeneration with prosthetic valves. Notwithstanding the theoretical challenges of greater tissue fragility in Marfan syndrome (MFS), AVSRS has been demonstrated to have equal outcomes in this condition as it does in those without MFS. The benefits of retaining the native aortic valve in this generally younger age group extend beyond those of avoiding the inconvenience and complications of prolonged exposure to anticoagulants and include ease of management for future aortic, cardiac and non-cardiac procedures which are the norm for these patients. The essential principles of AVSRS in MFS do not differ from those for the rest of the population. Successful repair and durable valve function depend on a sound understanding of the close interaction between the structure and function of this exquisitely designed piece of engineering. We are fortunate to have numerous tools in our surgical armamentarium to preserve these valves. It is the purpose of this paper to demystify the complex structure-function interactions of the aortic valve, thereby gaining an intuition for AVSRS. We will also elaborate on specific technical details of established techniques that we have found successful in preserving the normal function of these valves in the long term.

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.

Off-Pump Semicircular Annuloplasty: Effective Treatment of Concurrent Moderate Aortic Regurgitation

The treatment of aortic regurgitation (AR) in patients undergoing off-pump coronary artery bypass grafting (CABG) is a difficult problem. Aortic valve repair has become a promising therapy for AR. Various annuloplasty approaches have been used and have gained satisfactory results. Thus we adopted off-pump semicircular annuloplasty to treat concurrent moderate AR in 12 high-risk patients. Early follow-up results showed that this way is simple, safe, and effective.

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

BACKGROUND

The aim of this study was to assess effectiveness, stability, position, and expansibility of an expansible aortic annuloplasty ring with computed tomography (CT).

METHODS

Ten men (median age 51 years) scheduled for aortic root remodeling with implantation of external annuloplasty ring underwent contrast-enhanced CT of the aortic root preoperatively, postoperatively, and at a median of 21 months after operation. A reconstructed transverse double oblique view of the aortic base (AB) and of the new defined annuloplasty ring base (ARB; plane of the lower edge of the ring) in systole and diastole were obtained. The diameters, perimeter, and area were measured. In addition, the distances between AB and ARB in the nadir of each sinus were measured.

RESULTS

We found 12% reduction of the postoperative AB and 19% of ARB perimeter in both systole (p = 0.004, p < 0.001, respectively) and diastole (p = 0.001, p < 0.001, respectively) compared with preoperative. There was 22% reduction of the postoperative AB area in systole and 24% in diastole (p = 0.002, p = 0.001, respectively) and 33% reduction of the ARB area in systole and 32% in diastole (p < 0.001 for both) compared with the preoperative period. Nearly all measured variables in the follow-up period showed a slight increase compared with the postoperative period; however, they did not reach statistical significance. The postoperative systolic-diastolic differences in the three measured variables at the level of AB and ARB were statistically significant and were maintained throughout the follow-up period. The base of the ring was implanted 2 ± 2 mm at the right, 0 ± 1 mm at the left above the AB, and 2 (-3 to 2) mm at the noncoronary nadir below the AB.

CONCLUSIONS

This study demonstrates imaging evidence of the effectiveness, stability, and pulsatility of the annuloplasty ring in aortic root remodeling in follow-up and describes the exact position of the ring at the base of the aortic root.

New Insights Into Unicuspid Aortic Valve Disease in Adults: Not Just a Subtype of Bicuspid Aortic Valves

BACKGROUND

The clinical presentation, echocardiographic features, and patterns of aortic dilatation in unicuspid aortic valves (UAVs) are not well defined.

METHODS

From 2011 to 2015, all data from adult patients with confirmed UAVs (n = 42) who underwent aortic valve surgery were reviewed.

RESULTS

The mean age of the study population was 33.9 ± 1.7 years; 33 were male (78%). Mixed aortic valve disease (stenosis and regurgitation) was the most common mode of presentation (n = 25; 59%). Preoperative diagnosis of UAV was made in only 6 patients (14%). Preoperative transesophageal echocardiography in the operating room increased the diagnosis to 69% of the patients. The peak and mean aortic gradients were 80 ± 29 mm Hg and 50 ± 20 mm Hg, respectively. The aortic valve area was 1.1 ± 0.4 cm(2). Overall, 21% of patients (n = 9) had aortic dilatation (> 45 mm): 6 patients (14%) had isolated ascending aortic dilatation, 1 patient (2%) had isolated aortic root dilatation, and 2 patients (5%) had combined aortic root and ascending aortic dilatation. In contrast, 71% of patients (n = 30) had a dilated aortic annulus (> 25 mm). Mean aortic diameters measured using transesophageal echocardiography were: aortic annulus: 25.8 ± 3.4 mm; sinus of Valsalva: 32.1 ± 5 mm, sinotubular junction: 28.1 ± 5 mm, and ascending aorta: 36.2 ± 5 mm. The valve was repaired using a bicuspidization technique in 8 patients (19%) and replaced using a Ross procedure in 34 patients (81%).

CONCLUSIONS

UAVs remain significantly underdiagnosed in young adults with aortic valve disease. UAVs are associated with a distinct pattern of aortic dilatation, which is mainly present at the level of the aortic annulus. In a small proportion of patients, the valve can be surgically repaired.