A refined hemispheric model of normal human aortic valve and root geometry

Three-dimensional modelling of aortic leaflet coaptation and load-bearing surfaces: in silico design of aortic valve neocuspidizations

OBJECTIVES

Three-dimensional (3D) modelling of aortic leaflets remains difficult due to insufficient resolution of medical imaging. We aimed to model the coaptation and load-bearing surfaces of the aortic leaflets and adapt this workflow to aid in the design of aortic valve neocuspidizations.

METHODS

Geometric morphometrics, using landmarks and semilandmarks, was applied to the geometric determinants of the aortic leaflets from computed tomography, followed by an isogeometric analysis using Non-Uniform Rational Basis Splines (NURBS). Ten aortic valve models were generated, measuring determinants of leaflet geometry defined as 3D NURBS curves, and leaflet coaptation and load-bearing surfaces were defined as 3D NURBS surfaces. Neocuspidizations were obtained by either shifting the upper central coaptation landmark towards the sinotubular junction or using parametric neo-landmarks placed on a centreline drawn between the centroid of the aortic root base and centroid of a circle circumscribing the 3 upper commissural landmarks.

RESULTS

The ratio of the leaflet free margin length to the geometric height was 1.83, whereas the ratio of the commissural coaptation height to the central coaptation height was 1.93. The median coaptation surface was 137 mm2 (IQR 58) and the median load-bearing surface was 203 mm2 (60) per leaflet. Neocuspidization multiplied the central coaptation height by 3.7 and the coaptation surfaces by 1.97 and 1.92 using the native coaptation axis and centroid coaptation axis, respectively.

CONCLUSIONS

Geometric morphometrics reliably defined the coaptation and load-bearing surfaces of aortic leaflets, enabling an experimental 3D design for the in silico neocuspidization of aortic valves.

Selective Sinus Replacement for Aortic Root Aneurysm: Durable Approach in Selected Patients

BACKGROUND

Selective sinus replacement (SSR) allows a tailored repair approach in patients with sinus of Valsalva or asymmetric aortic root aneurysm. SSR avoids the need for coronary reimplantation for nondiseased sinuses and shortens operative time, although potential for late growth of retained sinuses exists. This study describes selection of patients and assesses operative outcomes and late root dimensions after SSR.

METHODS

From 2006 to 2020, 60 patients underwent SSR at a single referral institution. Mixed effect models were used to assess trajectory of postoperative growth of remaining sinuses, adjusting for age of the patient, valve morphology, and baseline root diameter.

RESULTS

Median age of the patients was 57 (interquartile range [IQR], 48-65) years. Twenty-four (40%) had a bicuspid aortic valve. Most patients (n = 55 [92%]) underwent single sinus replacement (n = 46 noncoronary, n = 9 right), whereas 5 (8%) underwent repair of both the right and noncoronary sinuses. Concomitant aortic valve replacement was performed in 15 patients (25%); aortic valve repair with internal ring annuloplasty or cusp plication was performed in 37 (62%). There was no operative death, stroke, renal failure, or respiratory failure. Median preoperative root diameter was 53 mm (IQR, 51-56 mm) vs 42 mm (IQR, 39-45 mm) at median imaging follow-up of 34 (IQR, 13-49) months. Rate of midterm root growth was 0.2 mm/y, and there were no late root reinterventions.

CONCLUSIONS

For patients with sinus of Valsalva or asymmetric root aneurysm, SSR is associated with excellent operative outcomes, and midterm follow-up suggests that the technique is durable. Longer term follow-up is needed to confirm continued stability of the aortic root.

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.

The Medical versus Zoological Concept of Outflow Tract Valves of the Vertebrate Heart

The anatomical elements that in humans prevent blood backflow from the aorta and pulmonary artery to the left and right ventriclesare the aortic and pulmonary valves, respectively. Each valve regularly consists of three leaflets (cusps), each supported by its valvular sinus. From the medical viewpoint, each set of three leaflets and sinuses is regarded as a morpho-functional unit. This notion also applies to birds and non-human mammals. However, the structures that prevent the return of blood to the heart in other vertebrates are notably different. This has led to discrepancies between physicians and zoologists in defining what a cardiac outflow tract valve is. The aim here is to compare the gross anatomy of the outflow tract valvular system among several groups of vertebrates in order to understand the conceptual and nomenclature controversies in the field.

Early results of geometric ring annuloplasty for bicuspid aortic valve repair during aortic aneurysm surgery

Objectives

Geometric ring annuloplasty has shown promise during bicuspid aortic valve repair for aortic insufficiency. This study examined early outcomes of bicuspid aortic valve repair associated with proximal aortic aneurysm replacement.

Methods

From September 2017 to November, 2021, 127 patients underwent bicuspid aortic valve repair with concomitant proximal aneurysm reconstruction. Patient age was 50.6 ± 12.7 years (mean ± standard deviation), male gender was 83%, New York Heart Association Class was 2 (1-2) (median [interquartile range]), and preoperative aortic insufficiency grade was 3 (2-4). Ascending aortic diameter was 50 (46-54) mm, and all patients had ascending aortic replacement. Forty patients had sinus diameters greater than 45 mm, prompting remodeling root procedures. A total of 105 patients had Sievers type 1 valves, 3 patients had type 0, and 7 patients had type 2. A total of 118 patients had primarily right/left fusion, 8 patients had right/nonfusion, and 1 patient had left/nonfusion. Leaflet reconstruction used central leaflet plication and cleft closure, with limited ultrasonic decalcification in 31 patients.

Results

Ring size was 23 (21-23) mm, and 26 of 40 root procedures were selective nonfused sinus replacements. Aortic clamp time was 139 (112-170) minutes, and bypass time was 178 (138-217) minutes. Postrepair aortic insufficiency grade was 0 (0-0) (P < .0001), and mean valve gradient was 10 (7-14) mm Hg. No early and 1 late mortality occurred. Four patients required reoperation for bleeding, and 4 patients required pacemakers. At a mean follow-up of 20 months (maximal 93), there were no valve-related complications, 5 late repair failures prompting valve replacement, and 1 death due to Coronavirus Disease 2019.

Conclusions

Geometric ring annuloplasty for bicuspid aortic valve repair with proximal aortic aneurysm reconstruction is safe and associated with good early outcomes. Further experience and follow-up will help inform long-term durability.

Aortic valve repair for isolated right coronary leaflet prolapse

Objectives

Isolated right coronary leaflet prolapse is a common cause of nonaneurysmal aortic insufficiency, but can rarely occur in patients with proximal aortic aneurysms. Standardized techniques for routine autologous repair of this disorder are presented.

Methods

Most aortic valve leaflet prolapse is isolated to the right coronary leaflet, with hypertension and annular dilatation being contributory. Echocardiographically, a posteriorly eccentric aortic insufficiency jet together with "fracture" of the right leaflet tip are diagnostic. Primary repair includes internal geometric ring annuloplasty to downsize and reshape the annulus, together with central plication of the prolapsing leaflet. Thickened, scarred, or retracted noduli are released using an ultrasonic aspirator. The goal is to achieve equivalent coaptation heights of ≥8 mm for all 3 leaflets.

Results

Three videos of 6 cases are provided to illustrate these techniques. In the first, 3 patients are shown with classic isolated right leaflet prolapse. In the second and third videos, alternative pathologies are presented for contrast. Applying the reconstructive approaches of geometric ring annuloplasty, leaflet plication, and ultrasonic nodular release, excellent early and late repair outcomes are obtainable in most patients.

Conclusions

The combination of aortic ring annuloplasty, central leaflet plication, and ultrasonic nodular release allows routine and standardized repair of right coronary leaflet prolapse, either isolated or concomitant with aneurysm surgery.

Early Outcomes of Patients Undergoing Neoaortic Valve Repair Incorporating Geometric Ring Annuloplasty

OBJECTIVES

During congenital heart surgery, the pulmonary valve and root may be placed into the systemic position, yielding a "neoaortic" valve. With the stress of systemic pressure, the pulmonary roots can dilate, creating aneurysms and/or neoaortic insufficiency (neoAI). This report analyzes the early outcomes of patients undergoing neoaortic valve repair incorporating geometric ring annuloplasty.

METHODS

Twenty-one patients underwent intended repair at six centers and formed the study cohort. Thirteen had previous Ross procedures, five had arterial switch operations, and three Fontan physiology. Average age was 21.7 ± 12.8 years (mean  ±  SD), 80% were male, and 11 (55%) had symptomatic heart failure. Preoperative neoAI Grade was 3.1  ±  1.1, and annular diameter was 30.7  ±  6.5 mm.

RESULTS

Valve repair was accomplished in 20/21, using geometric annuloplasty rings and leaflet plication (n = 13) and/or nodular release (n = 7). Fourteen had neoaortic aneurysm replacement (13 with root remodeling). Two underwent bicuspid valve repair. Six had pulmonary conduit changes, one insertion of an artificial Nodulus Arantius, and one resection of a subaortic membrane. Ring size averaged 21.9  ±  2.3 mm, and aortic clamp time was 171  ±  54 minutes. No operative mortality or major morbidity occurred, and postoperative hospitalization was 4.3  ±  1.4 days. At discharge, neoAI grade was 0.2  ±  0.4 (P < .0001), and valve mean gradient was ≤20 mm Hg. At average 18.0  ±  9.1 months of follow-up, all patients were asymptomatic with stable valve function.

CONCLUSIONS

Neoaortic aneurysms and neoAI are occasionally seen late following Ross, arterial switch, or Fontan procedures. Neoaortic valve repair using geometric ring annuloplasty, leaflet reconstruction, and root remodeling provides a patient-specific approach with favorable early outcomes.

Minimally invasive aortic valve repair using geometric ring annuloplasty

OBJECTIVES

As aortic valve repair (AVr) for aortic insufficiency (AI) expands, minimally invasive (Mi) approaches are increasingly being applied. Cardiac surgical techniques can be more difficult through small incisions, and this report analyzes medium-term outcomes for MiAVr facilitated by geometric ring annuloplasty.

METHODS

Since 2013, 58 patients were selected for AVr through upper sternotomy third-interspace incisions. The average age was 58.9 ± 15.4 (mean ± SD) years, 71% were male, and preoperative AI grade was 3.6 ± 0.8. Sixty-two percent (36/58) had a proximal aortic replacement for ascending aortic aneurysms (n = 26) and/or remodeling grafts for aortic root aneurysms (n = 10). Annuloplasty rings were placed subannularly (69% trileaflet; 31% bicuspid), and leaflet procedures were performed in 70%. The average ring diameter was 21.6 ± 1.4 mm, and the average aortic clamp time was 113 ± 35 min.

RESULTS

After repair, AI grade fell to an average of 0.5 ± 0.6 (p < .0001), with a mean valve gradient of 12.5 ± 7.1 mmHg. No operative mortalities or major complications occurred. Three patients required reoperations for bleeding, and two had pacemakers. At an average follow-up of 38 months (maximal 88 months), three late deaths and no valve-related complications were observed. Four patients required reoperative aortic valve replacement over follow-up, and Kaplan-Meier survival and freedom from reoperation both exceeded 80% at 88 months. At the last follow-up, the average AI grade was 0.7 ± 0.7, and the mean valve gradient was 12.7 ± 6.3 mmHg.

CONCLUSIONS

Geometric ring annuloplasty was safe and seemed to facilitate performing AVr ± proximal aortic replacement through Mi incisions. Hemodynamic improvements were significant, medium-term clinical outcomes were acceptable, and results could improve further with experience.

A modern approach to aortic valve insufficiency: Aortic root restoration via HAART 300 internal annuloplasty ring

BACKGROUND AND AIM OF THE STUDY

HAART 300 is an internal geometric annuloplasty ring. The safety and efficacy of this novel device in aortic valve (AV) repair in a single referral center are reported.

METHODS

Twenty patients with trileaflet AV insufficiency with ascending aorta and/or aortic root enlargement were included. Subannular implantation was performed to correct annular dilatation, whereas concomitant leaflet repair was performed whenever required. All but two patients also received ascending aorta replacement, whereas selective sinus replacement was performed in all but five patients.

RESULTS

Follow-up was for a maximum of 3.8 years and a mean of 2.2 years. Mean age was 54.2 years old. Moderate to severe preoperative AV insufficiency was noted in 75% of patients, whereas 70% of them had an ascending aorta over 45 mm. One patient was lost from follow-up. Overall mortality as well as major complication rates were zero. Early postoperatively, no more than mild AV regurgitation was detected, whereas only one patient appeared with moderate AV regurgitation during our 2.2-year follow-up. New York Heart Association class was also significantly lower compared to preoperative values and valve gradients remained low at last follow-up.

CONCLUSIONS

Geometric ring annuloplasty is a safe and effective valve sparing approach to deal with AV insufficiency contributing to overall root reconstruction. Short-term results are excellent rendering this easily reproducible and versatile method very attractive.

Leaflet Dimensions as a Guide to Remodeling Annuloplasty During Aortic Valve Repair

OBJECTIVE

In chronic aortic insufficiency (AI), the method and degree of annular downsizing required to achieve durable coaptation in aortic valve repair (AVr) remains poorly defined. This study evaluated the relationship between leaflet size and annular diameter to predict adequate annular sizing in remodeling AVr.

METHODS

Under regulatory supervision, 74 patients with chronic tri-leaflet AI underwent AVr using ring annuloplasty and leaflet reconstruction. Fifty-four (73%) had ascending aortic (n = 25) and/or root (n = 29) aneurysms, and aortic grafts were sized 5 to 7 mm larger than the rings. Intraoperatively, leaflet free-edge length (FEL) was measured with special ball sizers positioned in the coronary sinus, and "normal" annular diameter was predicted from the validated formula: Required "normal" diameter = FEL/1.5. "Normal" annular diameters predicted from FEL were compared with pathologic diameters measured intraoperatively with Hegar dilators, and both were correlated with gender, age, and BSA.

RESULTS

Average age was 62.1 ± 13.3 years (mean ± SD), 73% (54/74) were male, and 96% (71/74) had moderate-to-severe AI. All patients had annular dilatation, with a pathologic diameter 26.6 ± 2.3 mm before repair, and a predicted "normal" diameter of 21.7 ± 1.7 mm (P < 0.001). Both predicted and pathologic annular diameters were larger in men (P < 0.001), but no relationship existed with age. BSA correlated with both predicted and pathologic diameters, although variability was large.

CONCLUSIONS

Based on a simple validated method to predict "normal" annular diameter, all patients with chronic AI have some degree of annular dilatation. This finding implies that most AVr should include annuloplasty, with adequate and precise annular reduction based on leaflet size.

Automatic estimation of aortic and mitral valve displacements in dynamic CTA with 4D graph-cuts

The location of the mitral and aortic valves in dynamic cardiac imaging is useful for extracting functional derived parameters such as ejection fraction, valve excursions, and global longitudinal strain, and when performing anatomical structures tracking using slice following or valve intervention's planning. Completely automatic segmentation methods are still challenging tasks because of their fast movements and the different positions that prevent good visibility of the leaflets along the full cardiac cycle. In this article, we propose a processing pipeline to track the displacement of the aortic and mitral valve annuli from high-resolution cardiac four-dimensional computed tomographic angiography (4D-CTA). The proposed method is based on the dynamic separation of left ventricle, left atrium and aorta using statistical shape modeling and an energy minimization algorithm based on graph-cuts and has been evaluated on a set of 15 electrocardiography-gated 4D-CTAs. We report a mean agreement distance between manual annotations and our proposed method of 2.52±1.06 mm for the mitral annulus and 2.00±0.69 mm for the aortic valve annulus based on valve locations detected from manual anatomical landmarks. In addition, we show the effect of detecting the valvular planes on derived functional parameters (ejection fraction, global longitudinal strain, and excursions of the mitral and aortic valves).

Bicuspid aortic valve repair using geometric ring annuloplasty: A first-in-humans pilot trial

OBJECTIVE

As bicuspid aortic valve (BAV) repair evolves, more effective annular reduction and stabilization could be advantageous. A geometric annuloplasty ring has been developed, and 2-year regulatory outcomes of a first-in-humans pilot trial are reported.

METHODS

A prospective first-in-humans trial of BAV ring annuloplasty was completed in 16 patients. Patient age was 44.4 ± 11.3 (mean ± standard deviation) years, preoperative aortic insufficiency grade was 2.5 ± 1.0, New York Heart Association class 1.8 ± 0.4, and mean systolic gradient 13.4 ± 12.9 mm Hg. Three patients had Sievers type 0 BAV, 11 had type 1, and 2 were type 2. The Dacron-covered titanium rings had circular base geometry with 180° subcommissural posts and were implanted subannularly. Leaflets were reconstructed using plication/cleft closure, creating an effective height of ≥8 mm, even if modest gradients were induced.

RESULTS

Mean pre-repair annular diameter was 28.6 ± 3.3 mm, and the average ring diameter was 22.3 ± 1.6 mm. All valves required leaflet plication/reconstruction; pericardium was avoided; and 7 patients had aortic replacement for aneurysms. No early mortalities or major complications occurred. Two patients required early prosthetic valve replacement for technical errors, and all were between 24-38 months' postoperative at follow-up. No late mortalities or valve-related complications occurred, and all patients reverted to New York Heart Association class I. Aortic insufficiency reduction was significant to grade 0.9 ± 0.5 at 2-years (P < .0001). Mean valve gradients were acceptable (13.3 ± 5.0 mm Hg at 2 years; overall P = .11) and tended to fall over time (P < .0001).

CONCLUSIONS

Geometric ring annuloplasty was safe and effective for BAV repair. AI reduction was significant, valve gradients were satisfactory, and clinical outcomes were excellent. Geometric ring annuloplasty could simplify and standardize BAV repair.

Initial Application of a Bicuspid Aortic Annuloplasty Ring in Pediatric Cardiac Surgery

Aortic stenosis and aortic insufficiency (AI) are common valvular conditions that may necessitate repair or replacement of the aortic valve. Aortic valve replacement is associated with higher long-term complications and thus, a consistent, reliable method of repair is needed. This is especially true in the pediatric population where lifelong anticoagulation and development of recurrent aortic stenosisor aortic insufficiency are especially problematic. The Hemispherical Aortic Annuloplasty Reconstruction Technology ring has been developed and used for annular stabilization in adults with success, though its efficacy in the pediatric population has yet to be demonstrated. Herein, we discuss the use of a geometric ring in aortic valve repair for the pediatric patient.

Three-dimensional transesophageal echocardiography is an attractive alternative to cardiac multi-detector computed tomography for aortic annular sizing: Systematic review and meta-analysis

BACKGROUND

Cardiac imaging is the cornerstone of the pretranscatheter aortic valve replacement (TAVR) assessment. Multi-detector computed tomography (MDCT) is considered the conventional imaging modality. However, there is still no definitive gold standard. Targeted cohort of inoperable high-risk patients with underlying comorbidities, particularly renal impairment, makes apparent the need for MDCT alternative. We aimed to demonstrate the correlation extent between MDCT and three-dimensional transesophageal echocardiography (3DTEE) aortic annular area measures and to answer the question: Is 3DTEE a good alternative to MDCT?

METHODS

A systematic literature search and meta-analysis were conducted to evaluate the degree of correlation and agreement between 3DTEE and MDCT aortic annular sizing. A thorough assessment of EMBASE, PubMed, and Cochrane Central Register of Controlled Trials (CENTRAL) was performed. All studies comparing 3DTEE and MDCT in relation to aortic annular sizing were included.

RESULTS

Thirteen studies were included (N = 1228 patients). A strong linear correlation was found between 3DTEE and MDCT measurements of aortic annulus area (r = 0.84, P < 0.001), mean perimeter (r = 0. 0.85, P < 0.001), and mean diameter (r = 0.80, P < 0.001). Bland-Altman plots revealed smaller mean 3DTEE values in comparison to MDCT for aortic annular area, the mean difference being -2.22 mm² with 95% limits of agreement -12.79 to 8.36.

CONCLUSION

Aortic annulus measurements obtained by 3DTEE demonstrated a high level of correlation with those evaluated by MDCT. This makes 3DTEE a feasible choice for aortic annulus assessment, with advantage of real time assessment, lack of contrast, and no radiation exposure.

Geometric Ring Annuloplasty for Aortic Valve Repair During Aortic Aneurysm Surgery: Two-Year Clinical Trial Results

OBJECTIVE

An aortic annuloplasty ring could be useful for aortic valve repair. This trial evaluated intermediate-term outcomes of internal geometric ring annuloplasty for repair of trileaflet and bicuspid aortic insufficiency associated with ascending aortic and/or aortic root aneurysms.

METHODS

Under regulatory supervision, 47 patients with aortic insufficiency and ascending aortic (n = 22) and/or aortic root (n = 25) aneurysms were managed with aortic valve repair and aneurysm resection. Valve repair was performed using trileaflet (n = 40) or bicuspid (n = 7) internal geometric rings, together with leaflet reconstruction. Ascending aortic and/or remodeling root replacements were accomplished with Dacron grafts 5 to 7 mm larger than the rings. An Echo Core Lab provided independent echocardiographic assessments, and changes over time were evaluated by Friedman tests.

RESULTS

Mean ± SD age was 60 ± 14 years, 57% (27/47) were male, 15% (7/47) had bicuspid valves, 87% (41/47) had moderate-to-severe aortic insufficiency, and 13% (6/47) had mild aortic insufficiency. All patients had annular dilatation, with a mean ± SD of 26.5 ± 2.6 mm before repair, and mean ± SD ring sizes were 21.7 ± 1.7 mm. Follow-up was 42 months (mean = 27 months). No operative mortality or valve-related complications occurred. Two patients died beyond 1 year from nonvalve-related causes. One patient required valve replacement for repair failure. Survival free of complications or valve replacement was 94% at 2 years. Significant reduction in aortic insufficiency and New York Heart Association class were observed (P < 0.0001), and valve gradients remained low. No heart block or direct ring complications occurred.

CONCLUSIONS

In preliminary regulatory studies, aortic ring annuloplasty seemed safe and effective during aortic aneurysm surgery. This approach could help standardize aortic valve repair.

A comparison of aortic root measurements by echocardiography and computed tomography

OBJECTIVES

The aim of the study is to evaluate an optimal way to assess the dimensions of the aortic root and each of the sinuses of Valsalva and examine how a single measurement in 1 plane (echocardiography or 2-dimensional computed tomography) can underestimate the maximum dimension of the aortic root.

METHODS

Computed tomography and transthoracic echocardiography images of the aortic root and ascending aorta of 112 patients were analyzed. The minimum and maximum aortic root dimensions, the root perimeter, and the total area of all 3 sinuses of Valsalva were measured on a plane perpendicular to the long axis of the aorta using 3-dimensional multiplanar reconstruction. Moreover, the maximum root dimension was compared with the measurements obtained from the echocardiography and 2-dimensional computed tomography angiography measurements.

RESULTS

The difference in the measurements of the minimum and maximum root dimension was 5.4 ± 3.2 mm (range, 0-21 mm, P < .0001) and was significantly larger in patients with bicuspid aortic valves compared with those with tricuspid valves (6.3 ± 4 mm, range, 0-21 mm vs 4.9 ± 2.6 mm, range, 0-15 mm, P = .036). The maximum root dimension measured in 3-dimensional multiplanar reconstruction (49.1 ± 9.0 mm) differed significantly from the root dimension measured in transthoracic echocardiography in the parasternal long-axis view (44.8 ± 8.4 mm) and 2-dimensional computed tomography (axial plane: 45.5 ± 9.0 mm, coronal plane: 46.1 ± 8.8 mm, sagittal plane: 45.1 ± 8.9 mm) (P < .001).

CONCLUSIONS

The difference in the measurements of the minimum and maximum aortic root dimensions is significant and may exceed 20 mm, especially in patients with bicuspid aortic valves. Therefore, aortic root dimensions can be significantly underestimated with the measurement (echocardiography, computed tomography angiography) performed in only 1 plane.

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.

A Geometric Model of the Normal Human Aortic Root and Design of a Fully Anatomic Aortic Root Graft

Objective

Available aortic root grafts generally flare outward in the sinus region, and this feature improves procedural ease. However, no current device is based on normal aortic root geometry, and a fully anatomic aortic root graft could further facilitate valve-sparing root operations.

Methods

To develop a model of the normal human aortic root, high-resolution computed tomographic angiogram images from 11 normal human aortas generated high-density x, y, z coordinates of valve and root structures in Mathematica. Three-dimensional least-squares regression analyses assessed geometry of the aortic valve and root. Shapes and dimensions were quantified, and minor variations in geometry were simplified during graft design.

Results

Normal aortic valve and root geometry was represented as three leaflet-sinus general ellipsoids nested within a cylindrical aorta. Sinotubular junction diameter was 5 mm larger than the valve base—with a slight funnel-shaped outward commissural flare but cylindrical geometry above the midvalve. The valve base was elliptical, but the midvalve and the sinotubular junction were circular above the midvalve level. Commissural locations on the base circumference were equidistant. On the basis of average three-dimensional geometry, a root graft was designed for root remodeling procedures—to be used with an internal geometric annuloplasty ring of the same design.

Conclusions

An aortic root graft was designed on the basis of mathematical analyses of computed tomographic angiogram images. The design incorporated three anatomic sinuses, commissural symmetry, and compatibility with geometric ring annuloplasty. The anatomic graft may prove useful for restoring aortic root geometry toward normal during aortic valve and root surgery.

Leaflet reconstructive techniques for aortic valve repair

BACKGROUND

Refining leaflet reconstruction has become a primary issue in aortic valve repair. This descriptive analysis reviews leaflet pathology, repair techniques, and early results in a prospective regulatory trial of aortic valve repair.

METHODS

Sixty-five patients underwent valve repair for predominant moderate to severe aortic insufficiency (AI). The mean age was 63 ± 13 years, and 69% of the patients were male. Ascending aortic/root replacement was required in 62%. As a first step, ring annuloplasty was performed, and then leaflet repair included leaflet plication for prolapse, nodular unfolding, double pericardial patching of commissural defects or holes, complete pericardial leaflet replacement, leaflet extension, and Gore-Tex reinforcement. Leaflet techniques and causes of adverse outcomes were evaluated.

RESULTS

The follow-up time was 2-years maximal and 0.9 years mean, with a survival of 97%. Eighty percent of patients required repair of leaflet defects: leaflet prolapse (52/65-80%), ruptured commissures (6/65-9%), leaflet holes (4/65-6%), and nodular retraction (6/65-9%). The average preoperative AI grade of 2.9 ± 0.8 fell to 0.7 ± 0.7 (p < 0.0001). Three patients (4.6%) required interval valve replacement because of (1) suture untying, (2) iatrogenic leaflet tear, or (3) diphtheroid endocarditis. Five other patients experienced grade 2 or grade 3 AI: probable suture untying in 1 patient, ineffective leaflet extensions in 2 patients, and unsuccessful Gore-Tex reinforcements in 2 patients. Two patients with single pericardial leaflet replacements and all those with double pericardial reconstructions did well.

CONCLUSIONS

Leaflet defects are common in patients with moderate to severe AI. Leaflet plication, nodular unfolding, and double pericardial patching performed well. Gore-Tex and leaflet extension seemed less satisfactory. Standardization and experience with leaflet reconstruction will be important for optimizing the outcomes of aortic valve repair.

The functional aortic annulus in the 3D era: focus on transcatheter aortic valve replacement for the perioperative echocardiographer

The functional aortic annulus represents a sound clinical framework for understanding the components of the aortic root complex. Recent three-dimensional imaging analysis has demonstrated that the aortic annulus frequently is elliptical rather than circular. Comprehensive three-dimensional quantification of this aortic annular geometry by transesophageal echocardiography and/or multidetector computed tomography is essential to guide precise prosthesis sizing in transcatheter aortic valve replacement to minimize paravalvular leak for optimal clinical outcome. Furthermore, three-dimensional transesophageal echocardiography accurately can quantify additional parameters of the functional aortic annulus such as coronary height for complete sizing profiles for all valve types in transcatheter aortic valve replacement. Although it is maturing rapidly as a clinical imaging modality, its role in transcatheter aortic valve replacement is seen best as complementary to multidetector computed tomography in a multidisciplinary heart team model.

Aortic valve adaptation to aortic root dilatation: insights into the mechanism of functional aortic regurgitation from 3-dimensional cardiac computed tomography

BACKGROUND

The 3-dimensional relationship between aortic root and cusp is essential to understand the mechanism of aortic regurgitation (AR) because of aortic root dilatation (ARD). We sought to test the hypothesis that the stretched cusps in ARD enlarge to compensate for ARD.

METHODS AND RESULTS

Computed tomography imaged 92 patients (57 with ARD, 29 with moderate to severe AR, 28 without significant AR) and 35 normal controls. Specialized 3-dimensional software measured individual cusp surface areas relative to maximal mid-sinus cross-sectional area and minimal 3-dimensional annular area, coaptation area fraction, and asymmetry of sinus volumes and intercommissural distances. Total open cusp surface area increased (P<0.001) from 7.6±1.4 cm(2)/m(2) in normals to 12.9±2.2 cm(2)/m(2) in AR-negative and 15.2±3.3 cm(2)/m(2) in AR-positive patients. However, the ratio of closed cusp surface area to maximal mid-sinus area, reflecting cusp adaptation, decreased from normals to AR-negative to AR-positive patients (1.38±0.20, 1.15±0.15, 0.88±0.15; P<0.001), creating the lowest coaptation area fraction. Cusp distensibility (closed diastolic versus open area) decreased from 20% in controls and AR-negative patients to 5% in AR-positive patients (P<0.001). Multivariate determinants of AR and coaptation area fraction reflected both sinus size and cusp-to-annular adaptation. ARD was also progressively asymmetrical with root size, and individual cusp surface areas failed to match this asymmetry.

CONCLUSIONS

Aortic cusp enlargement occurs in ARD, but cusp adaptation and distensibility become limited in prominent, asymmetrical ARD, leading to AR. Optimal AR repair tailored to individual patient anatomy can benefit from appreciating valve adaptation and 3-dimensional relationships; understanding cusp adaptation mechanisms may ultimately provide therapeutic opportunities to improve such compensation.

Aortic root geometry in patients with aortic stenosis assessed by real-time three-dimensional transesophageal echocardiography

BACKGROUND

The authors hypothesized that aortic root geometry is different between bicuspid and tricuspid aortic stenosis (AS) that can be assessed using real-time three-dimensional (3D) transesophageal echocardiography. The aims of this study were (1) to validate the accuracy of 3D transesophageal echocardiographic measurements of the aortic root against multidetector computed tomography as a reference, (2) to determine the difference of aortic root geometry between patients with tricuspid and bicuspid AS, and (3) to assess its impact on pressure recovery.

METHODS

In protocol 1, 3D transesophageal echocardiography and contrast-enhanced multidetector computed tomography were performed in 40 patients. Multiplanar reconstruction was used to measure the aortic annulus, the sinus of Valsalva, and the sinotubular junction area, as well as the distance and volume from the aortic annulus to the sinotubular junction. In protocol 2, the same 3D transesophageal echocardiographic measurements were performed in patients with tricuspid AS (n = 57) and bicuspid AS (n = 26) and in patients without AS (n = 32). The energy loss coefficient was also measured in patients with AS.

RESULTS

In protocol 1, excellent correlations of aortic root geometric parameters were noted between the two modalities. In protocol 2, compared with patients without AS, those with tricuspid AS had smaller both sinotubular junction areas and longitudinal distances, resulting in a 23% reduction of aortic root volume. In contrast, patients with bicuspid AS had larger transverse areas and longitudinal distances, resulting in a 30% increase in aortic root volume. The energy loss coefficient revealed more frequent reclassification from severe AS to moderate AS in patients with tricuspid AS (17%) compared with those with bicuspid AS (10%).

CONCLUSIONS

Three-dimensional transesophageal echocardiography successfully revealed different aortic root morphologies between tricuspid and bicuspid AS, which have different impacts on pressure recovery.

Design Characteristics of a Three-Dimensional Geometric Aortic Valve Annuloplasty Ring

Objective

A full geometric annuloplasty ring could facilitate aortic valve repair. The purpose of this report was to document the design of such a ring using mathematical analyses of normal human aortic valve computed tomographic angiograms.

Methods

One-millimeter axial slices of high-resolution computed tomographic angiograms from 11 normal aortic roots were used to generate high-density x, y, and z coordinates of valve structures in Mathematica. Three-dimensional least squares regression analyses of leaflet-sinus coordinates were used to assess geometry of aortic valve and root structures.

Results

Normal valve geometry could be represented as three leaflet-sinus general ellipsoids nested within an elliptical aortic root. Minor-major diameter ratio of the valve base was 0.60 ± 0.07, and elliptical geometry extended vertically up the commissures. By contrast, leaflet-sinus horizontal circumferences were fairly circular (diameter ratios, 0.82–0.87), and the left coronary/noncoronary commissural post was located at the posterior base minor diameter-circumference junction, with the center of the right coronary leaflet opposite. Post location on the circumference was symmetrical, with a deviation of only ±2% to ±3% from 33.3% symmetry. Commissural posts flared outward by 5 to 10 degrees, and leaflet areas were statistically equivalent ( P > 0.10). From end diastole to midsystole, the aortic root became less elliptical (diameter ratio increased by 0.15), but root area expanded minimally (less than +5%). A one-piece rigid annuloplasty ring was designed with 2:3 base ellipticality, three 10-degree outwardly flaring symmetrical posts, and post height = base circumference/2π.

Conclusions

A three-dimensional aortic annuloplasty ring was designed that could prove useful for enhancing applicability and stability of aortic valve repair.