Aortic valve repair update

A 3D-Printed Externally Adjustable Symmetrically Extensible (EASE) Aortic Annuloplasty Ring for Root Repair and Aortic Valve Regurgitation

PURPOSE

The valve-sparing aortic root replacement (VSARR) procedure was developed to preserve the aortic valve apparatus to replace aneurysmal aortic roots with synthetic grafts and to eliminate associated aortic regurgitation (AR). However, residual post-repair AR is not uncommon and has been found to be associated with recurrent AR and future reoperation.

METHODS

We designed and manufactured a 3D-printed, external adjustable symmetrically extensible (EASE) aortic annuloplasty ring that can symmetrically reduce the aortic annulus diameter via a radial constriction, compliant mechanism. An ex vivo porcine VSARR model with annular dilation and AR was developed (n = 4) and used for hemodynamic, echocardiography, and high-speed videography data collection.

RESULTS

After ring annuloplasty repair using the EASE aortic ring, the regurgitant fraction decreased from 23.6 ± 6.9% from the VSARR model to 7.4 ± 5.6% (p = 0.05), which was similar to that measured from baseline with a regurgitant fraction of 10.2 ± 3.9% (p = 0.34). The leaflet coaptation height after annuloplasty repair also significantly increased from that measured in VSARR model (0.4 ± 0.1 cm) to 0.9 ± 0.1 cm (p = 0.0004), a level similar to that measured in baseline (1.1 ± 0.1 cm, p = 0.28).

CONCLUSION

Using an ex vivo VSARR model, the EASE ring successfully reduced AR by reducing the annular diameter and improving leaflet coaptation. With its broad applicability and ease of use, this device has the potential to have a significant impact on patients suffering worldwide from AR due to root aneurysms.

Surgical outcomes of aortic valve repair for specific aortic valve cusp characteristics; retraction, calcification, and fenestration

OBJECTIVES

We investigated the predictive value of aortic valve cusp retraction, calcification, and fenestration for aortic valvuloplasty feasibility.

METHODS

Multicenter data were collected for 2082 patients who underwent surgical aortic valvuloplasty or aortic valve replacement. The study population had retraction, calcification, or fenestration in at least one aortic valve cusp. Controls had normal or prolapsed cusps.

RESULTS

All cusp characteristics demonstrated significantly increased odds ratios [ORs] for switch to valve replacement. This effect was strongest for cusp retraction, followed by calcification and fenestration (OR, 25.14; P ≤ .001; OR, 13.50, P ≤ .001; OR, 12.32, P ≤ .001). Calcification and retraction displayed increased odds for developing grade 4 aortic regurgitation compared with grade 0 or 1 combined on average over time (OR, 6.67; P ≤ .001; OR, 4.13; P = .038). Patients with cusp retraction showed increased risk for reintervention at 1- and 2-year follow-up after aortic valvuloplasty (hazard ratio, 5.66; P ≤ .001; hazard ratio, 3.22, P = .007). Cusp fenestration was the only group showing neither an increased risk of postoperative severe aortic regurgitation (P = .57) or early reintervention (P = .88) compared with the control group.

CONCLUSIONS

Aortic valve cusp retraction, calcification, and fenestration were all related to increased rates of switch to valve replacement. Calcification and retraction were associated with recurrence of severe aortic regurgitation. Retraction was related to early reintervention. Fenestration was neither associated with recurrence of severe aortic regurgitation or reintervention. This indicates that surgeons are well able to distinguish aortic valve repair candidates in patients with cusp fenestration.

Electrospun nanofibrous membrane for biomedical application

Electrospinning is a simple, cost-effective, flexible, and feasible continuous micro-nano polymer fiber preparation technology that has attracted extensive scientific and industrial interest over the past few decades, owing to its versatility and ability to manufacture highly tunable nanofiber networks. Nanofiber membrane materials prepared using electrospinning have excellent properties suitable for biomedical applications, such as a high specific surface area, strong plasticity, and the ability to manipulate their nanofiber components to obtain the desired properties and functions. With the increasing popularity of nanomaterials in this century, electrospun nanofiber membranes are gradually becoming widely used in various medical fields. Here, the research progress of electrospun nanofiber membrane materials is reviewed, including the basic electrospinning process and the development of the materials as well as their biomedical applications. The main purpose of this review is to discuss the latest research progress on electrospun nanofiber membrane materials and the various new electrospinning technologies that have emerged in recent years for various applications in the medical field. The application of electrospun nanofiber membrane materials in recent years in tissue engineering, wound dressing, cancer diagnosis and treatment, medical protective equipment, and other fields is the main topic of discussion in this review. Finally, the development of electrospun nanofiber membrane materials in the biomedical field is systematically summarized and prospects are discussed. In general, electrospinning has profound prospects in biomedical applications, as it is a practical and flexible technology used for the fabrication of microfibers and nanofibers.

This review summarizes recent research on the application of electrospun nanofiber membranes as tissue engineering materials for the cardiovascular system, motor system, nervous system, and other clinical aspects.

Research on the application of electrospun nanofiber membrane materials as protective products is discussed in the context of the current epidemic situation.

Examples and analyses of recent popular applications in tissue engineering, wound dressing, protective products, and cancer sensors are presented.

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.

Comparison of bicuspid and tricuspid aortic valve repair

OBJECTIVES

The aim of this study was to compare the outcomes of tricuspid aortic valve (TAV) and bicuspid aortic valve (BAV) repair.

METHODS

We assessed mortality, freedom from reoperation and the rate of aortic valve regurgitation recurrence. Mortality in both groups was compared with expected survival, and risk factors for reoperation were identified.

RESULTS

From January 2010 to April 2020, a total of 368 elective aortic valve repair procedures were performed, including 223 (60.6%) in patients with TAV. The perioperative mortality was 0.7% in the BAV group and 3.6% in the TAV group (P = 0.079). Estimated survival at 5 years in the BAV versus TAV group was 97 ± 3% vs 80 ± 6%, respectively (P < 0.001). Freedom from reoperation at 5 years in the TAV versus BAV group was 96 ± 3% vs 93 ± 4%, respectively (P = 0.28). Grade 2 or more aortic valve regurgitation was noted in 9.9% of BAV patients and 11% of TAV patients (P = 0.66). Reoperation was predicted by cusp perforation [hazard ratio 15.86 (4.44-56.61); P < 0.001], the use of pericardial patch [hazard ratio 8.58 (1.96-37.53); P = 0.004] and aortic valve annulus diameter >27.5 mm [hazard ratio 3.07 (0.99-9.58); P = 0.053].

CONCLUSIONS

BAV repair is as durable as TAV repair. BAV is not a predictor of a higher rate of reoperations. BAV repair yields survival comparable to expected. Cusp perforation, aortic valve annulus diameter >27.5 mm and the use of pericardial patch adversely impact long-term outcome of aortic valve repair.

Narrative review of the contemporary surgical treatment of unicuspid aortic valve disease

Unicuspid aortic valve disease (UAVD) is a frequent and long-lasting challenge for adult congenital heart disease centers. UAVD patients become usually symptomatic in their twenties or thirties and require a surgical treatment plan which should respect their complete lifespan combined with an adequate quality of life. Unfortunately, all current surgical strategies of congenital aortic valve disease bear some important limitations: (I) Aortic valve replacement using bioprosthetic valves is associated with early structural degeneration and leads frequently to re-operations. (II) Mechanical valves are commonly associated with lifelong risk of severe bleeding due to oral anticoagulation. (III) Using a pulmonary autograft (i.e., Ross procedure) for aortic valve replacement is associated with excellent long-term results in non-elderly patients. However, failure of pulmonary autograft or pulmonary homograft may require re-operations. (IV) Aortic valve repair or Ozaki procedure is only performed in a few heart centers worldwide and is associated with a limited reproducibility and early patch degeneration, suture dehiscence or increased risk of endocarditis. In contrast to degenerative tricuspid aortic valve disease, UAVD remains relatively understudied and reports on UAVD treatment are rare and usually limited to retrospective single-center observations. For this review, we searched PubMed for papers in the English language by using the search words unicuspid aortic valve, congenital aortic valve, Ross procedure, Ozaki procedure, aortic valve repair, mechanical/bioprosthetic aortic replacement, homograft. We read the abstracts of relevant titles to confirm their relevance, and the full papers were then extracted. References from extracted papers were checked for additional relevant reports. This review summarizes current surgical treatment strategies for UAVD including aortic valve replacement using bioprosthetic or mechanical valves, homografts, pulmonary autografts (i.e., Ross procedure) and aortic valve repair techniques for UAV. Furthermore, Ozaki procedure will be discussed.

Biofabrication of poly(l-lactide-co-ε-caprolactone)/silk fibroin scaffold for the application as superb anti-calcification tissue engineered prosthetic valve

In this study, electrospun scaffolds were fabricated by blending poly(l-lactide-co-ε-caprolactone) (PLCL) and silk fibroin (SF) with different ratios, and further the feasibility of electrospun PLCL/SF scaffolds were evaluated for application of tissue engineered heart valve (TEHV). Scanning electron microscopy (SEM) results showed that the surface of PLCL/SF electrospun scaffolds was smooth and uniform while the mechanical properties were appropriate as valve prosthesis. In vitro cytocompatibility evaluation results demonstrated that all of the PLCL/SF electrospun scaffolds were cytocompatible and valvular interstitial cells (VICs) cultured on PLCL/SF scaffolds of 80/20 & 70/30 ratios exhibited the best cytocompatibility. The in vitro osteogenic differentiation of VICs including alkaline phosphatase (ALP) activity and quantitative polymerase chain reaction (qPCR) assays indicated that PLCL/SF scaffolds of 80/20 & 90/10 ratios behaved better anti-calcification ability. In the in vivo calcification evaluation model of rat subdermal implantation, PLCL/SF scaffolds of 80/20 & 90/10 ratios presented better anti-calcification ability, which was consistent with the in vitro results. Moreover, PLCL/SF scaffolds of 80/20 & 70/30 ratios showed significantly enhanced cell infiltration and M2 macrophage with higher CD206+/CD68+ ratio. Collectively, our data demonstrated that electrospun scaffolds with the PLCL/SF ratio of 80/20 hold great potential as TEHV materials.

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.

Aortic Valve Regurgitation: Pathophysiology and Implications for Surgical Intervention in the Era of TAVR

Aortic insufficiency (AI) or regurgitation is caused by the malcoaptation of the aortic valve (AV) cusps due to intrinsic abnormalities of the valve itself, a dilatation or geometric distortion of the aortic root, or by some combination thereof. In recent years, there has been an increase in the number of studies suggesting that AI is an active disease process caused by a combination of factors including but not limited to alteration of specific molecular pathways, genetic predisposition, and changes in the mechanotransductive properties of the AV apparatus. As the surgical management of AV disease continues to evolve, increasingly sophisticated surgical and percutaneous techniques for AV repair and replacement, including transcatheter aortic valve replacement (TAVR), have become more commonplace and will likely continue to expand as new devices are introduced. However, these techniques necessitate frequent reappraisal of the biological and mechanobiological mechanisms underlying AV regurgitation to better understand the risk factors for AI development and recurrence following surgical intervention as well as expand our limited knowledge on patient selection for such procedures. The aim of this review is to describe some of the putative mechanisms implicated in the development of AI, dissect some of the cross-talk among known and possible signaling pathways leading to valve remodeling, identify association between these pathways and pharmacological approaches, and discuss the implications for surgical and percutaneous approaches to AV repair in replacement in the TAVR era.

A novel device for technical standardization of valve-sparing aortic root reimplantation

Among valve-sparing aortic root replacement techniques developed for the treatment of aortic root aneurysms and aortic insufficiency, the reimplantation technique (the David procedure) has proved to provide excellent outcomes in experienced hands. However, it involves certain challenges in technical standardization, particularly for graft sizing, which is still far from standardization. A novel device was developed to facilitate and provide all the measurements in high precision and accuracy required for the David procedure. The device allows easy, rapid, and accurate acquisition of the patient"s data and appropriate configuration of the aortic valve, irrespective of the surgeon's subjective evaluations. This all-in-one device provides all the major parameters including graft size, effective height, graft preparation, and simulation of the aortic coaptation. The device was successfully tested on a Devotini aortic root simulator and on a bovine heart ex vivo. The device proposed herein to be used for reimplantation has one explicit advantage: all valve geometry to be reconstructed and repaired can be simulated on the device with all its elements, in particular, the commissures and the cusps. Thus, all that is necessary can be clearly visualized in a manner whatever the configuration the surgeon prefers, particularly the creation of the effective height.

Bicuspid Aortic Valve: An Update in Morphology, Genetics, Biomarker, Complications, Imaging Diagnosis and Treatment

The bicuspid aortic valve, a kind of heart disease that comes from parents, has been paid attention around the world. Although most bicuspid aortic valve (BAV) patients will suffer from some complications including aortic stenosis, aortic regurgitation, endocarditis, and heart dysfunction in the late stage of the disease, there is none symptom in the childhood, which restrains us to diagnose and treatment in the onset phase of BAV. Hemodynamic abnormalities induced by the malformations of the valves in BAV patients for a long time will cause BAV-associated aortopathy: including progress aortic dilation, aneurysm, dissection and rupture, cardiac cyst and even sudden death. At present, preventive surgical intervention is the only effective method used in this situation and the diameter of the aorta is the primary reference criterion for surgery. And the treatment effects are always not satisfactory for patients and clinicians. Therefore, we need more methods to evaluate the progression of BAV and the surgery value and the appropriate intervention time by combining basic research with clinical treatment. In this review, advances in morphology, genetic, biomarkers, diagnosis and treatments are summarized, which expects to provide an update about BAV. It is our supreme expectations to provide some evidences for BAV early screening and diagnosis, and in our opinion, personalized surgical strategy is the trend of future BAV treatment.

Biomechanical characterization and comparison of different aortic root surgical techniques

OBJECTIVES

Understanding the biomechanical impact of aortic valve-sparing techniques is important in an era in which surgical techniques are developing and are increasingly being used based on biomechanical understanding that is essential in the refining of existing techniques. The objective of this study was to describe how the valve-sparing remodelling (Yacoub) and reimplantation (David Type-1) techniques affect the biomechanics of the native aortic root in terms of force distribution and geometrical changes.

METHODS

Two force transducers were implanted into 22 pigs, randomized to 1 of 3 groups (David = 7, native = 7 and Yacoub = 8) along with 11 sonomicrometry crystals and 2 pressure catheters. Force and geometry data were combined to obtain the local structural stiffness in different segments of the aortic root.

RESULTS

The radial structural stiffness was not different between groups (P = 0.064) at the annular level; however, the David technique seemed to stabilize the aortic annulus more than the Yacoub technique. In the sinotubular junction, the native group was more compliant (P = 0.036) with the right-left coronary segment than the intervention groups. Overall, the native aortic root appeared to be more dynamic at both the annular level and the sinotubular junction than both intervention groups.

CONCLUSIONS

In conclusion, the David procedure may stabilize the aortic annulus more than the Yacoub procedure, whereas the leaflet opening area was larger in the latter (P = 0.030). No difference (P = 0.309) was found in valve-opening delay between groups. The 2 interventions show similar characteristics at the sinotubular junction, whereas the David technique seemed more restrictive at the annular level than the Yacoub technique.

Which technique of cusp repair is durable in reimplantation procedure?

OBJECTIVES

We aimed to ascertain the durability of cusp repair techniques used in reimplantation procedures.

METHODS

Between 2000 and 2015, 249 patients (mean age, 49 ± 17 years) with aortic insufficiency underwent the reimplantation procedure. The pathology was acute aortic dissection in 24 and non-dissection in 225 patients. Preoperative aortic regurgitation (AR) was absent in 9, 1+ in 19, 2+ in 20, 3+ in 71 and 4+ in 120 patients. The mean aortic root and ascending aortic diameters were 47 ± 9 mm and 38 ± 7 mm, respectively. The following techniques of cusp repair were used: none (83), central plication (130), free margin reinforcement (57) and patch repair (19). Annual echocardiography was performed. Freedom from moderate aortic insufficiency and aortic valve reoperation were calculated by the Kaplan-Meier method. Factors influencing the freedom from moderate or severe AR were calculated by proportional hazard analysis.

RESULTS

Mean follow-up period was 56  ±  44 months. Freedom from moderate or severe AR was 82%±3% and 77% ± 4% at 5 and 8 years, respectively, whereas freedom from aortic valve reoperation was 93%±8% and 87% ± 3% at 5 and 8 years, respectively. Recurrent AR and infection were causes of reoperation in 13 and 3 patients, respectively. Preoperative cusp prolapse, technique of free margin reinforcement used and patch repair were significant factors for recurrent AR by proportional hazard analysis. Central plication was not a significant factor for recurrent AR.

CONCLUSIONS

Preoperative cusp prolapse was a risk factor, whereas central plication was not a risk factor for recurrent AR. Free margin reinforcement had a positive effect, whereas patch repair had a negative effect on aortic valve durability.

Cardiovascular tissue engineering: From basic science to clinical application

Valvular heart disease is an increasing population health problem and, especially in the elderly, a significant cause of morbidity and mortality. The current treatment options, such as mechanical and bioprosthetic heart valve replacements, have significant restrictions and limitations. Considering the increased life expectancy of our aging population, there is an urgent need for novel heart valve concepts that remain functional throughout life to prevent the need for reoperation. Heart valve tissue engineering aims to overcome these constraints by creating regenerative, self-repairing valve substitutes with life-long durability. In this review, we give an overview of advances in the development of tissue engineered heart valves, and describe the steps required to design and validate a novel valve prosthesis before reaching first-in-men clinical trials. In-silico and in-vitro models are proposed as tools for the assessment of valve design, functionality and compatibility, while in-vivo preclinical models are required to confirm the remodeling and growth potential of the tissue engineered heart valves. An overview of the tissue engineered heart valve studies that have reached clinical translation is also presented. Final remarks highlight the possibilities as well as the obstacles to overcome in translating heart valve prostheses into clinical application.

Does aortic valve repair in valve-sparing aortic root reconstruction compromise the longevity of the procedure?

OBJECTIVES:

The effect of performing aortic valve repair in combination with valve-sparing operation on the length of time for which patients are free from reoperation is unclear. The objective of this study was to determine if the performance of aortic valve repair during valve-sparing operation modified the freedom from reoperation time.

METHODS:

From January 2003 to July 2014, 78 patients with a mean age of 49±15 years underwent valve-sparing operation. Sixty-eight percent of these patients were male. Twenty-two (28%) aortic valve repair procedures were performed in this patient population. In the aortic valve repair + valve-sparing operation group, 77.3% of patients had moderate/severe aortic insufficiency, while in the valve-sparing operation group, 58.6% of patients had moderate/severe aortic insufficiency (ns = not significant). Additionally, 13.6% of patients in the aortic valve repair + valve-sparing operation group had functional class III/IV, while 14.2% of patients in the valve-sparing operation group had functional class III/IV (ns).

RESULTS:

The in-hospital and late mortality rates, for the aortic valve repair + valve-sparing operation and valve-sparing operation groups were similar, as they were 4.5% and 3.6%; and 0% and 1.8%, respectively. In the aortic valve repair + valve-sparing operation group, 0% of patients presented moderate/severe aortic insufficiency during late follow-up, while in the valve-sparing operation group, 14.2% of patients presented with moderate/severe aortic insufficiency during this period (ns). In the aortic valve repair + valve-sparing operation group, 5.3% of patients presented with functional class III/IV, while in the valve-sparing operation group, 4.2% of patients presented with functional class III/IV (ns). In the aortic valve repair + valve-sparing operation group, 0% of patients required reoperation, while in the valve-sparing operation group, 3.6% of patients required reoperation over a mean follow-up period of 1621±1156 days (75 patients).

CONCLUSION:

Valve-sparing operation is a safe and long-lasting procedure and performance of aortic valve repair when necessary does not increase risk of reoperation on the aortic valve.