Advances in aortic valve repair: focus on functional approach, clinical outcomes, and central role of echocardiography

Midterm Results of an Algorithmic 3-Pronged Approach to Bicuspid Aortic Valve Repair

BACKGROUND

This study evaluated midterm outcomes of a 3-pronged algorithm for bicuspid aortic valve (BAV) repair. Valve-sparing root reimplantation (VSRR) was performed for patients with aortic root dilatation. In those without a root aneurysm, external subannular ring (ESAR) was performed for annuli ≥28 mm and subcommissural annuloplasty (SCA) for annuli <28 mm.

METHODS

This was a retrospective review of prospectively collected data of 242 patients undergoing primary BAV repair from April 29, 2004, to March 1, 2023, at a single institution. Primary end points were mortality, structural valve degeneration (SVD), which was defined as a composite of more than moderate aortic insufficiency or severe aortic stenosis, and reintervention.

RESULTS

The algorithm was used to treat 201 patients; of these, 130 underwent VSRR, 35 had ESAR, and 36 underwent SCA. Most were men with mean age of 43.8 years (SD, 12.0 years), which was similar between groups. Preoperative aortic insufficiency more than moderate was more common for ESAR compared with VSRR and SCA (74.3% vs 37.7% vs 44.4%, P < .001). At 30 days, mortality was 0.8% (n = 1) for VSRR and 0% for ESAR and SCA. At 6 years, overall Kaplan-Meier survival was 98.9% (95% CI, 97.3%-100%), with no differences between groups (P = .5). The cumulative incidence of SVD was 4.7% (95% CI, 0.1%-9.2%) for VSRR, 6.4% (95% CI, 0%-14.6%) for ESAR, and 0% for SCA (P = .4). Similarly, the cumulative incidence of reintervention with all-cause mortality as a competing risk was 2.2% (95% CI, 0.4%-6.9%), 6.1% (95% CI, 1%-17.9%), and 0% for VSRR, ESAR, and SCA, respectively (P = .506).

CONCLUSIONS

A 3-pronged algorithmic approach to BAV repair results in excellent survival and freedom from reoperation at 6 years.

Intraoperative Transesophageal Echocardiographic Assessment of Aortic Valve Repair in a Child - What to Look for?

ABSTRACT

Aortic valve (AV) repair is the desired surgical treatment option for young patients with aortic regurgitation (AR). It is considered as a class I indication for the surgical treatment of severeAR. The success of an AV repair depends on the detailed intraoperative transesophageal echocardiographic (TEE) examination which should fulfil the information required by the surgeon. The objective of this echo round is to describe the role of intraoperative TEE in systematic evaluation of the AV, before and after repair.

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.

Novel bicuspid aortic valve model with aortic regurgitation for hemodynamic status analysis using an ex vivo simulator

OBJECTIVE

The objective was to design and evaluate a clinically relevant, novel ex vivo bicuspid aortic valve model that mimics the most common human phenotype with associated aortic regurgitation.

METHODS

Three bovine aortic valves were mounted asymmetrically in a previously validated 3-dimensional-printed left heart simulator. The non-right commissure and the non-left commissure were both shifted slightly toward the left-right commissure, and the left and right coronary cusps were sewn together. The left-right commissure was then detached and reimplanted 10 mm lower than its native height. Free margin shortening was used for valve repair. Hemodynamic status, high-speed videography, and echocardiography data were collected before and after the repair.

RESULTS

The bicuspid aortic valve model was successfully produced and repaired. High-speed videography confirmed prolapse of the fused cusp of the baseline bicuspid aortic valve models in diastole. Hemodynamic and pressure data confirmed accurate simulation of diseased conditions with aortic regurgitation and the subsequent repair. Regurgitant fraction postrepair was significantly reduced compared with that at baseline (14.5 ± 4.4% vs 28.6% ± 3.4%; P = .037). There was no change in peak velocity, peak gradient, or mean gradient across the valve pre- versus postrepair: 293.3 ± 18.3 cm/sec versus 325.3 ± 58.2 cm/sec (P = .29), 34.3 ± 4.2 mm Hg versus 43.3 ± 15.4 mm Hg (P = .30), and 11 ± 1 mm Hg versus 9.3 ± 2.5 mm Hg (P = .34), respectively.

CONCLUSIONS

An ex vivo bicuspid aortic valve model was designed that recapitulated the most common human phenotype with aortic regurgitation. These valves were successfully repaired, validating its potential for evaluating valve hemodynamics and optimizing surgical repair for bicuspid aortic valves.

Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making in the Operating Room: A Surgery-Based Approach: From the American Society of Echocardiography in Collaboration with the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons

Intraoperative transesophageal echocardiography is a standard diagnostic and monitoring tool employed in the management of patients undergoing an entire spectrum of cardiac surgical procedures, ranging from "routine" surgical coronary revascularization to complex valve repair, combined procedures, and organ transplantation. Utilizing a protocol as a starting point for imaging in all procedures and all patients enables standardization of image acquisition, reduction in variability in quality of imaging and reporting, and ultimately better patient care. Clear communication of the echocardiographic findings to the surgical team, as well as understanding the impact of new findings on the surgical plan, are paramount. Equally important is the need for complete understanding of the technical steps of the surgical procedures being performed and the complications that may occur, in order to direct the postprocedure evaluation toward aspects directly related to the surgical procedure and to provide pertinent echocardiographic information. The rationale for this document is to outline a systematic approach describing how to apply the existing guidelines to questions on cardiac structure and function specific to the intraoperative environment in open, minimally invasive, or hybrid cardiac surgery procedures.

An intraoperative test device for aortic valve repair

OBJECTIVE

Aortic valve repair is currently in transition from surgical improvisation to a reproducible operation and an option for many patients with aortic regurgitation. Our research efforts at improving reproducibility include development of methods for intraoperatively testing and visualizing the valve in its diastolic state.

METHODS

We developed a device that can be intraoperatively secured in the transected aorta allowing the aortic root to be pressurized and the closed valve to be inspected endoscopically. Our device includes a chamber that can be pressurized with crystalloid solution and ports for introduction of an endoscope and measuring gauges. We show use of the device in explanted porcine hearts to visualize the aortic valve and to measure leaflet coaptation height in normal valves and in valves that have undergone valve repair procedures.

RESULTS

The procedure of introducing and securing the device in the aorta, pressurizing the valve, and endoscopically visualizing the closed valve is done in less than 1 minute. The device easily and reversibly attaches to the aortic root and allows direct inspection of the aortic valve under conditions that mimic diastole. It enables the surgeon to intraoperatively study the valve immediately before repair to determine mechanisms of incompetence and immediately after the repair to assess competence. We also show its use in measuring valve leaflet coaptation height in the diastolic state.

CONCLUSIONS

This device enables more relevant prerepair valve assessment and also enables a test of postrepair valve competence under physiological pressures.

Ultrasound for In Vitro, Noninvasive Real-Time Monitoring and Evaluation of Tissue-Engineered Heart Valves

Tissue-engineered heart valves are developed in bioreactors where biochemical and mechanical stimuli are provided for extracellular matrix formation. During this phase, the monitoring possibilities are limited by the need to maintain the sterility and integrity of the valve. Therefore, noninvasive and nondestructive techniques are required. As such, optical imaging is commonly used to verify valve's functionality in vitro. It provides important information (i.e., leaflet symmetry, geometric orifice area, and closing and opening times), which is, however, usually limited to a singular view along the central axis from the outflow side. In this study, we propose ultrasound as a monitoring method that, in contrast to established optical imaging, can assess the valve from different planes, scanning the whole three-dimensional geometry. We show the potential benefits associated with the application of ultrasound to bioreactors, in advancing heart valve tissue engineering from design to fabrication and in vitro maturation. Specifically, we demonstrate that additional information, otherwise unavailable, can be gained to evaluate the valve's functionality (e.g., coaptation length, and effective cusp height and shape). Furthermore, we show that Doppler techniques provide qualitative visualization and quantitative evaluation of the flow through the valve, in real time and throughout the whole in vitro fabrication phase.

Aortic Valve Cusp Coaptation Surface Area Using 3-Dimensional Transesophageal Echocardiography Correlates with Severity of Aortic Valve Insufficiency

OBJECTIVE

The aim of this study was to test both in humans and using finite element (FE) aortic valve (AV) models whether the coaptation surface area (CoapSA) correlates with aortic insufficiency (AI) severity due to dilated aortic roots to determine the validity and utility of 3-dimensional transesophageal echocardiographic-measured CoapSA.

DESIGN

Two-pronged, clinical and computational approach.

SETTING

Single university hospital.

PARTICIPANTS

The study comprised 10 patients with known AI and 98 FE simulations of increasingly dilated human aortic roots.

INTERVENTIONS

The CoapSA was calculated using intraoperative 3-dimensional transesophageal echocardiography data of patients with isolated AI and compared with established quantifiers of AI. In addition, the CoapSA and effective regurgitant orifice area (EROA) were determined using FE simulations.

MEASUREMENTS AND MAIN RESULTS

In the 10 AI patients, regurgitant fraction (RF) increased with EROA (R² = 0.77, p = 0.0008); CoapSA decreased with RF (R² = 0.72, p = 0.0020); CoapSA decreased with EROA (R² = 0.71, p = 0.0021); and normalized CoapSA (CoapSA / [Ventriculo-Aortic Junction × Sinotubular Junction]) decreased with EROA (R² = 0.60, p = 0.0088). In the 98 FE simulations, normalized CoapSA decreased with EROA (R² = 0.50, p = 0.0001).

CONCLUSIONS

In both human and FE AV models, CoapSA was observed to be inversely correlated with AI severity, EROA, and RF, thereby supporting the validity and utility of 3D TEE-measured CoapSA. A clinical implication is the expectation that high values of CoapSA, measured intraoperatively after AV repairs, would correlate with better long-term outcomes of those repairs.

Dynamic Three-Dimensional Geometry of the Aortic Valve Apparatus-A Feasibility Study

OBJECTIVE

To provide (1) an overview of the aortic valve (AV) apparatus anatomy and nomenclature, and (2) data regarding the normal AV apparatus geometry and dynamism during the cardiac cycle obtained from three-dimensional transesophageal echocardiography (3D TEE).

DESIGN

Retrospective feasibility study.

SETTING

A single-center university teaching hospital.

PARTICIPANTS

The study was performed on data of 10 patients with a nonregurgitant, nonstenotic aortic valve undergoing cardiac surgery.

INTERVENTIONS

Intraoperative 3D TEE was performed on all the participants using the Siemens ACUSON SC2000 ultrasound system and Z6Ms transducer (Siemens Medical Systems, Mountainview, CA).

MEASUREMENTS AND MAIN RESULTS

Dynamic offline analyses were performed with Siemens eSie valve analytical software in a semiautomated fashion. Forty-five parameters were exported of which 13 were selected and analyzed. The cardiac cycle was divided into 4 quartiles to account for frame-rate variations. The annulus, sinus of Valsalva (SoV) and sinotubular junction (STJ) areas, diameter, perimeter and height, aortic leaflet height, leaflet coaptation height, and aortic valve-mitral valve angle changed significantly during the cardiac cycle (p < 0.001). STJ expanded more than both the annulus and the SoV (p < 0.001). The maximum aortic valve leaflet height change was greater in the left and right versus noncoronary leaflet (p < 0.001).

CONCLUSIONS

The semiautomated AV apparatus dynamic assessment using eSie valve software is a clinically feasible technique and can be performed readily in the operating room. It has the potential to significantly impact intraoperative decision-making in cases suitable for AV repair. The AV apparatus is a dynamic structure and demonstrates significant changes during the cardiac cycle.

Intraoperative echocardiographic delineation of the high take-off coronary ostia during an extensive surgical repair of the bicuspid aortic valve and dilated sinotubular junction: a case report

Background

This study reports the efficacy of intraoperative transesophageal echocardiography (TEE) for evaluation of high take-off coronary ostia and proximal coronary arterial flows as an alternative to preoperative coronary angiography.

Case presentation

In a 65-year old male undergoing the bicuspid aortic valve (BAV) repair and the extensive remodeling of dilated sinus and tubular junction, and preoperative coronary angiography were unsuccessfully completed due to an allergic reaction to the contrast medium. Intraoperative TEE by employing various 3-dimensional volume images of coronary ostia and Doppler tracings of the coronary arterial flows enabled a thorough pre-procedural evaluation of the high take-off coronary arteries and post-procedural evaluation by confirming the absence of any compromise in coronary arterial flow.

Conclusion

In the present case, intraoperative application of various TEE imaging modalities enabled comprehensive evaluation of high-taking off coronary artery, as an alternative to preoperative coronary angiography, in a patient undergoing an extensive aortic valve and aortic root repair procedure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0250-x) contains supplementary material, which is available to authorized users.

Surgical reconstruction of semilunar valves in the growing child: Should we mimic the venous valve? A simulation study

OBJECTIVES

Neither heart valve repair methods nor current prostheses can accommodate patient growth. Normal aortic and pulmonary valves have 3 leaflets, and the goal of valve repair and replacement is typically to restore normal 3-leaflet morphology. However, mammalian venous valves have bileaflet morphology and open and close effectively over a wide range of vessel sizes. We propose that they might serve as a model for pediatric heart valve reconstruction and replacement valve design. We explore this concept using computer simulation.

METHODS

We use a finite element method to simulate the ability of a reconstructed cardiac semilunar valve to close competently in a growing vessel, comparing a 3-leaflet design with a 2-leaflet design that mimics a venous valve. Three venous valve designs were simulated to begin to explore the parameter space.

RESULTS

Simulations show that for an initial vessel diameter of 12 mm, the venous valve design remains competent as the vessel grows to 20 mm (67%), whereas the normal semilunar design remains competent only to 13 mm (8%). Simulations also suggested that systolic function, estimated as effective orifice area, was not detrimentally affected by the venous valve design, with all 3 venous valve designs exhibiting greater effective orifice area than the semilunar valve design at a given level of vessel growth.

CONCLUSIONS

Morphologic features of the venous valve design make it well suited for competent closure over a wide range of vessel sizes, suggesting its use as a model for semilunar valve reconstruction in the growing child.

Surgical repair of congenital aortic regurgitation by aortic root reduction: A finite element study

During surgical reconstruction of the aortic valve in the child, the use of foreign graft material can limit durability of the repair due to inability of the graft to grow with the child and to accelerated structural degeneration. In this study we use computer simulation and ex vivo experiments to explore a surgical repair method that has the potential to treat a particular form of congenital aortic regurgitation without the introduction of graft material. Specifically, in an aortic valve that is regurgitant due to a congenitally undersized leaflet, we propose resecting a portion of the aortic root belonging to one of the normal leaflets in order to improve valve closure and eliminate regurgitation. We use a structural finite element model of the aortic valve to simulate the closed, pressurized valve following different strategies for surgical reduction of the aortic root (e.g., triangular versus rectangular resection). Results show that aortic root reduction can improve valve closure and eliminate regurgitation, but the effect is highly dependent on the shape and size of the resected region. Only resection strategies that reduce the size of the aortic root at the level of the annulus produce improved valve closure, and only the strategy of resecting a large rectangular portion-extending the full height of the root and reducing root diameter by approximately 12% - is able to eliminate regurgitation and produce an adequate repair. Ex vivo validation experiments in an isolated porcine aorta corroborate simulation results.

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.

3D-echo in preoperative assessment of aortic cusps effective height

Effective height, which represents the height difference between the central free margins and the aortic insertion lines can be easily determined by 2-D echocardiography and allows for identification of prolapse in the native cusps and assessment of prolapse correction after valve repair. Nonetheless, it allows to see only two of three aortic valve (AV) coaptation planes and this may lead to misunderstanding of the underlying pathophysiological mechanism for aortic regurgitation and hence in unsuccessful repair. In contrast, 3D transoesophageal echocardiography and multiple plane reconstruction lets visualize all the three coaptation planes between the AV cusps and it represents an invaluable tool in the assessment of aortic valve geometry. It is highly recommendable before AV repair to accurately study the complex three dimensional cusps anatomy and their geometric interrelation with aortic root.

Perioperative transesophageal echocardiography for aortic dissection

PURPOSE

Aortic dissection is an infrequent but serious condition that often requires immediate operative intervention. We explore recent developments in the classification of aortic dissection and perioperative transesophageal echocardiography that assist with quantifying the severity of disease and facilitate its management.

PRINCIPAL FINDINGS

We describe the pivotal role of echocardiography in relation to key surgical considerations such as cannulation, aortic root surgery, perfusion in the aortic arch vessels, stenting in hybrid arch repair, and timing of preventative surgery.

CONCLUSION

Developments in the classification of aortic dissection have improved our perspective and understanding of the key presenting features that affect mortality. Improvements in patient outcome may be achieved in part by appropriately timed echocardiography-guided surgery.

Straightening of curved pattern of collagen fibers under load controls aortic valve shape

The network of collagen fibers in the aortic valve leaflet is believed to play an important role in the strength and durability of the valve. However, in addition to its stress-bearing role, such a fiber network has the potential to produce functionally important shape changes in the closed valve under pressure load. We measured the average pattern of the collagen network in porcine aortic valve leaflets after staining for collagen. We then used finite element simulation to explore how this collagen pattern influences the shape of the closed valve. We observed a curved or bent pattern, with collagen fibers angled downward from the commissures toward the center of the leaflet to form a pattern that is concave toward the leaflet free edge. Simulations showed that these curved fiber trajectories straighten under pressure load, leading to functionally important changes in closed valve shape. Relative to a pattern of straight collagen fibers running parallel to the leaflet free edge, the concave pattern of curved fibers produces a closed valve with a 40% increase in central leaflet coaptation height and with decreased leaflet billow, resulting in a more physiological closed valve shape. Furthermore, simulations show that these changes in loaded leaflet shape reflect changes in leaflet curvature due to modulation of in-plane membrane stress resulting from straightening of the curved fibers. This effect appears to play an important role in normal valve function and may have important implications for the design of prosthetic and tissue engineered replacement valves.

Three-dimensional echocardiography and en face views of the aortic valve: technical communication

With the resurgence in popularity of aortic valve (AV) repair, detailed anatomical information of the AV has become invaluable for surgical decision making as well as for evaluation of success postrepair. Perioperative 3-dimensional echocardiography is optimally suited to assist in repair planning. The volumetric nature of the 3-dimensional data allows accurate derivation of qualitative and quantitative measurements. A uniform approach to imaging and description of echocardiographic AV anatomy is essential to facilitate communication across specialties.

Intraoperative transesophageal echocardiographic imaging of double valve repair for aortic and mitral stenosis

An intraoperative echocardiographic evaluation to determine the feasibility and adequacy of the valve repair procedure is crucial for a successful repair. However, aortic valve repair in severe aortic stenosis (AS) is very limited and, consequently, its intraoperative echocardiographic evaluation has not been described well. Here, we describe an intraoperative transesophageal echocardiographic evaluation of a double-valve repair procedure for a patient with severe AS, moderate aortic insufficiency, and severe mitral stenosis.