Bicuspid aortic valve disease and ascending aortic aneurysms: gaps in knowledge. Cardiol Res Pract. 2012;2012:145202. [PMID: 23198270 PMCID: PMC3503270 DOI: 10.1155/2012/145202]

Predictive machine learning models for ascending aortic dilatation in patients with bicuspid and tricuspid aortic valves undergoing cardiothoracic surgery: a prospective, single-centre and observational study

OBJECTIVES

The objective of this study was to develop clinical classifiers aiming to identify prevalent ascending aortic dilatation in patients with bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV).

DESIGN AND SETTING

A prospective, single-centre and observational cohort.

PARTICIPANTS

The study involved 543 BAV and 491 TAV patients with aortic valve disease and/or ascending aortic dilatation, excluding those with coronary artery disease, undergoing cardiothoracic surgery at the Karolinska University Hospital (Sweden).

MAIN OUTCOME MEASURES

Predictors of high risk of ascending aortic dilatation (defined as ascending aorta with a diameter above 40 mm) were identified through the application of machine learning algorithms and classic logistic regression models.

EXPOSURES

Comprehensive multidimensional data, including valve morphology, clinical information, family history of cardiovascular diseases, prevalent diseases, demographic details, lifestyle factors, and medication.

RESULTS

BAV patients, with an average age of 60.4±12.4 years, showed a higher frequency of aortic dilatation (45.3%) compared with TAV patients, who had an average age of 70.4±9.1 years (28.9% dilatation, p <0.001). Aneurysm prediction models for TAV patients exhibited mean area under the receiver-operating-characteristic curve (AUC) values above 0.8, with the absence of aortic stenosis being the primary predictor, followed by diabetes and high-sensitivity C reactive protein. Conversely, prediction models for BAV patients resulted in AUC values between 0.5 and 0.55, indicating low usefulness for predicting aortic dilatation. Classification results remained consistent across all machine learning algorithms and classic logistic regression models.

CONCLUSION AND RECOMMENDATION

Cardiovascular risk profiles appear to be more predictive of aortopathy in TAV patients than in patients with BAV. This adds evidence to the fact that BAV-associated and TAV-associated aortopathy involves different pathways to aneurysm formation and highlights the need for specific aneurysm preventions in these patients. Further, our results highlight that machine learning approaches do not outperform classical prediction methods in addressing complex interactions and non-linear relations between variables.

Comprehensive review of aortic aneurysms, dissections, and cardiovascular complications in connective tissue disorders

Connective tissue disorders, including Marfan syndrome (MS) and Ehlers-Danlos syndrome (EDS), are characterized by genetic mutations affecting connective tissue structural integrity. These disorders significantly elevate the risk of aortic dissection, a life-threatening condition. This comprehensive review delves into the intricate interplay between connective tissue disorders and aortic dissection, shedding light on the clinical features, pathophysiology, genetic underpinnings, diagnostic approaches, clinical management, associated comorbidities, and prognosis, mainly focusing on MS and EDS, while also exploring rare connective tissue disorders and forms of cutis laxa contributing to aortic pathology.

Characteristics and outcomes of the Spanish registry for pediatric patients with bicuspid aortic valve (REVAB)

INTRODUCTION AND OBJECTIVES

Bicuspid aortic valve (BAV) disorder is the most common congenital heart disease. The aim of this study was to describe the characteristics of 0- to 18-year olds with BAV in a population-based registry.

METHODS

Data from all pediatric patients were obtained from the Spanish registry for pediatric patients with bicuspid aortic valve (REVAB) (< 18 years). For data analysis, patients with BAV were divided into 2 groups by their features: isolated BAV and BAV with associated congenital heart disease.

RESULTS

We included 1681 patients from 33 hospitals. Males accounted for 69.6% (n = 1158). Valve morphology was horizontal in 63.4% (n = 1012) and pure (Sievers type 0) in 28.4% (n=469). Isolated BAV was present in 63.7% (n=1060), and concomitant left-sided obstructive lesions in 23.4% (n=390). Interventions were required in 8.6% (n=145).

CONCLUSION

These data represent the first large, population-based description of the clinical presentations and outcomes of patients enrolled in the Spanish registry for pediatric patients with bicuspid aortic valve.

Calibration of the Mechanical Boundary Conditions for a Patient-Specific Thoracic Aorta Model Including the Heart Motion Effect

OBJECTIVE

We propose a procedure for calibrating 4 parameters governing the mechanical boundary conditions (BCs) of a thoracic aorta (TA) model derived from one patient with ascending aortic aneurysm. The BCs reproduce the visco-elastic structural support provided by the soft tissue and the spine and allow for the inclusion of the heart motion effect.

METHODS

We first segment the TA from magnetic resonance imaging (MRI) angiography and derive the heart motion by tracking the aortic annulus from cine-MRI. A rigid-wall fluid-dynamic simulation is performed to derive the time-varying wall pressure field. We build the finite element model considering patient-specific material properties and imposing the derived pressure field and the motion at the annulus boundary. The calibration, which involves the zero-pressure state computation, is based on purely structural simulations. After obtaining the vessel boundaries from the cine-MRI sequences, an iterative procedure is performed to minimize the distance between them and the corresponding boundaries derived from the deformed structural model. A strongly-coupled fluid-structure interaction (FSI) analysis is finally performed with the tuned parameters and compared to the purely structural simulation.

RESULTS AND CONCLUSION

The calibration with structural simulations allows to reduce maximum and mean distances between image-derived and simulation-derived boundaries from 8.64 mm to 6.37 mm and from 2.24 mm to 1.83 mm, respectively. The maximum root mean square error between the deformed structural and FSI surface meshes is 0.19 mm. This procedure may prove crucial for increasing the model fidelity in replicating the real aortic root kinematics.

The hidden unicuspid: Recurring aortic stenosis post-valvuloplasty from a unicuspid aortic valve masquerading as bicuspid

Unicuspid aortic valves (UAV) account for 0.2 % of cardiac valvular disorders and present with early-onset aortic stenosis (AS) during adolescence or early adulthood. We present a case of a 17-year-old male with recurring AS. He was diagnosed with bicuspid aortic valve (BAV) two years previously and treated with balloon valvuloplasty, which relieved symptoms before that. Multimodality imaging work-up revealed the precise morphology of UAV, consistent with the surgical findings. The patient received a St. Jude mechanical valve (St Paul; MN, USA) which resolved his symptoms. A thorough radiologic evaluation is therefore required for the accurate diagnosis of UAVs. While 2-dimensional (2D) transthoracic echocardiography (TTE) often constitutes the initial modality for evaluating UAVs, 3D-TTE, transesophageal echocardiography, and cardiac computed tomography are used as confirmatory diagnostic tools. Balloon valvuloplasty reports good outcomes in BAV but is associated with an increased rate of symptom recurrence, repeated surgical procedures, and higher mortality in UAVs, underscoring the importance of an accurate pre-operative diagnosis.

Learning objectives

1.Unicuspid aortic valve (UAV) should be considered in the differential diagnosis of severe aortic stenosis during childhood.2.3D-transthoracic echocardiogram, transesophageal echocardiogram, and cardiac computed tomography (CT) can confirm the diagnosis of a UAV.3.Cardiac CT can additionally assess for accompanying abnormalities of the great vessels in UAV patients.4.Balloon valvuloplasty reports good outcomes in bicuspid aortic valve but is associated with an increased rate of symptom recurrence in UAV patients.

Analysis of local extracellular matrix identifies different aetiologies behind bicuspid and tricuspid aortic valve degeneration and suggests therapies

Aortic valve degeneration (AVD) is a life-threatening condition that has no medical treatment and lacks individual therapies. Although extensively studied with standard approaches, aetiologies behind AVD are unclear. We compared abundances of extracellular matrix (ECM) proteins from excised valve tissues of 88 patients with isolated AVD of normal tricuspid (TAV) and congenital bicuspid aortic valves (BAV), quantified more than 1400 proteins per ECM sample by mass spectrometry, and demonstrated that local ECM preserves molecular cues of the pathophysiological processes. The BAV ECM showed enrichment with fibrosis markers, namely Tenascin C, Osteoprotegerin, and Thrombospondin-2. The abnormal physical stress on BAV may cause a mechanical injury leading to a continuous Tenascin C-driven presence of myofibroblasts and persistent fibrosis. The TAV ECM exhibited enrichment with Annexin A3 (p = 1.1 × 10-16 and the fold change 6.5) and a significant deficit in proteins involved in high-density lipid metabolism. These results were validated by orthogonal methods. The difference in the ECM landscape suggests distinct aetiologies between AVD of BAV and TAV; warrants different treatments of the patients with BAV and TAV; elucidates the molecular basis of AVD; and implies possible new therapeutic approaches. Our publicly available database (human_avd_ecm.surgsci.uu.se) is a rich source for medical doctors and researchers who are interested in AVD or heart ECM in general. Systematic proteomic analysis of local ECM using the methods described here may facilitate future studies of various tissues and organs in development and disease.

The Complex Relationship between Hypoxia Signaling, Mitochondrial Dysfunction and Inflammation in Calcific Aortic Valve Disease: Insights from the Molecular Mechanisms to Therapeutic Approaches

Calcific aortic valve stenosis (CAVS) is among the most common causes of cardiovascular mortality in an aging population worldwide. The pathomechanisms of CAVS are such a complex and multifactorial process that researchers are still making progress to understand its physiopathology as well as the complex players involved in CAVS pathogenesis. Currently, there is no successful and effective treatment to prevent or slow down the disease. Surgical and transcatheter valve replacement represents the only option available for treating CAVS. Insufficient oxygen availability (hypoxia) has a critical role in the pathogenesis of almost all CVDs. This process is orchestrated by the hallmark transcription factor, hypoxia-inducible factor 1 alpha subunit (HIF-1α), which plays a pivotal role in regulating various target hypoxic genes and metabolic adaptations. Recent studies have shown a great deal of interest in understanding the contribution of HIF-1α in the pathogenesis of CAVS. However, it is deeply intertwined with other major contributors, including sustained inflammation and mitochondrial impairments, which are attributed primarily to CAVS. The present review aims to cover the latest understanding of the complex interplay effect of hypoxia signaling pathways, mitochondrial dysfunction, and inflammation in CAVS. We propose further hypotheses and interconnections on the complexity of these impacts in a perspective of better understanding the pathophysiology. These interplays will be examined considering recent studies that shall help us better dissect the molecular mechanism to enable the design and development of potential future therapeutic approaches that can prevent or slow down CAVS processes.

Stroke and Noninfective Native Valvular Disease

PURPOSE OF REVIEW

Embolic stroke of undetermined source is a challenging clinical entity. While less common than atrial fibrillation and endocarditis, many noninfective heart valve lesions have been associated with stroke and may be considered as culprits for cerebral infarcts when other more common causes are excluded. This review discusses the epidemiology, pathophysiology, and management of noninfective valvular diseases that are commonly associated with stroke.

RECENT FINDINGS

Calcific debris from degenerating aortic and mitral valves may embolize to the cerebral vasculature causing small- or large-vessel ischemia. Thrombus which may be adherent to calcified valvular structures or left-sided cardiac tumors may also embolize resulting in stroke. Tumors themselves, most commonly myxomas and papillary fibroelastomas, may fragment and travel to the cerebral vasculature. Despite this broad differential, many types of valve diseases are highly comorbid with atrial fibrillation and vascular atheromatous disease. Thus, a high index of suspicion for more common causes of stroke is needed, especially given that treatment for valvular lesions typically involves cardiac surgery whereas secondary prevention of stroke due to occult atrial fibrillation is readily accomplished with anticoagulation.

Cardiovascular Diseases and Zinc

Zinc is structurally and functionally essential for more than 300 enzymes and 2000 transcription factors in human body. Intracellular labile zinc is the metabolically effective zinc and tiny changes in its concentrations significantly affect the intracellular signaling and enzymatic responses. Zinc is crucial for the embrionic and fetal development of heart. Therefore, it is shown to be related with a variety of congenital heart defects. It is involved in epithelial-to-mesenchymal transformation including endocardial cushion development, which is necessary for atrioventricular septation as well as the morphogenesis of heart valves. In atherosclerosis, monocyte endothelial adhesion, and diapedesis, activation and transformation into macrophages and forming foam cells by the ingestion of oxidized LDL are monocyte related steps which need zinc. Intracellular zinc increases intracellular calcium through a variety of pathways and furthermore, zinc itself can work as a second messenger as calcium. These demonstrate the significance of intracellular zinc in heart failure and arterial hypertension. However, extracellular zinc has an opposite effect by blocking calcium channels, explaining decreased serum zinc levels, contrary to the increased cardiomyocyte and erythrocyte zinc levels in hypertensive subjects. These and other data in the literature demonstrate that zinc has important roles in healthy and diseased cardiovascular system but zinc-cardiovascular system relationship is so complex that, it has not been explained in all means. In this article, we try to review some of the available knowledge about this complex relationship.

Are Thoracic Aortic Aneurysm Patients at Increased Risk for Cardiovascular Diseases?

Objectives: Abdominal aortic aneurysms are associated with a sharply increased cardiovascular risk. Cardiovascular risk management is therefore recommended in prevailing guidelines for abdominal aneurysm patients. It has been hypothesized that associated risk relates to loss of aortic compliance. If this hypothesis is correct, observations for abdominal aneurysms would also apply to thoracic aortic aneurysms. The objective of this study is to test whether thoracic aneurysms are also associated with an increased cardiovascular risk burden. Methods: Patients who underwent aortic valve or root surgery were included in the study (n = 239). Cardiovascular risk factors were studied and atherosclerosis was scored based on the preoperative coronary angiographies. Multivariate analyses were performed, controlling for cardiovascular risk factors and aortic valve morphology. Comparisons were made with the age- and gender-matched general population and non-aneurysm patients as control groups. A thoracic aortic aneurysm was defined as an aortic aneurysm of ≥45 mm. Results: Thoracic aortic aneurysm was not associated with an increased coronary atherosclerotic burden (p = 0.548). Comparison with the general population revealed a significantly higher prevalence of hypertension (61.4% vs. 32.2%, p < 0.001) and a lower prevalence of diabetes (1.4% vs. 13.1%, p = 0.001) in the thoracic aneurysm group. Conclusions: The extreme cardiovascular risk associated with abdominal aortic aneurysms is location-specific and not explained by loss of aortic compliance. Thoracic aortic aneurysm, in contrast to abdominal, is not part of the atherosclerotic disease spectrum and, therefore, cardiovascular risk management does not need to be implemented in treatment guidelines of isolated thoracic aneurysms. Hypertension should be treated.

Validating In Silico and In Vitro Patient-Specific Structural and Flow Models with Transcatheter Bicuspid Aortic Valve Replacement Procedure

INTRODUCTION

Bicuspid aortic valve (BAV) is the most common congenital cardiac malformation, which had been treated off-label by transcatheter aortic valve replacement (TAVR) procedure for several years, until its recent approval by the Food and Drug Administration (FDA) and Conformité Européenne (CE) to treat BAVs. Post-TAVR complications tend to get exacerbated in BAV patients due to their inherent aortic root pathologies. Globally, due to the paucity of randomized clinical trials, clinicians still favor surgical AVR as the primary treatment option for BAV patients. While this warrants longer term studies of TAVR outcomes in BAV patient cohorts, in vitro experiments and in silico computational modeling can be used to guide the surgical community in assessing the feasibility of TAVR in BAV patients. Our goal is to combine these techniques in order to create a modeling framework for optimizing pre-procedural planning and minimize post-procedural complications.

MATERIALS AND METHODS

Patient-specific in silico models and 3D printed replicas of 3 BAV patients with different degrees of post-TAVR paravalvular leakage (PVL) were created. Patient-specific TAVR device deployment was modeled in silico and in vitro-following the clinical procedures performed in these patients. Computational fluid dynamics simulations and in vitro flow studies were performed in order to obtain the degrees of PVL in these models.

RESULTS

PVL degree and locations were consistent with the clinical data. Cross-validation comparing the stent deformation and the flow parameters between the in silico and the in vitro models demonstrated good agreement.

CONCLUSION

The current framework illustrates the potential of using simulations and 3D printed models for pre-TAVR planning and assessing post-TAVR complications in BAV patients.

Patients With Bicuspid Aortic Stenosis Demonstrate Adverse Left Ventricular Remodeling and Impaired Cardiac Function Before Surgery With Increased Risk of Postoperative Heart Failure

BACKGROUND

Differences in adverse cardiac remodeling between patients who have bicuspid (BAV) and tricuspid aortic valve (TAV) with severe isolated aortic stenosis (AS) and its prognostic impact after surgical aortic valve replacement remains unclear. We sought to investigate differences in preoperative diastolic and systolic function in patients with BAV and TAV who have severe isolated AS and the incidence of postoperative heart failure hospitalization and mortality.

METHODS

Two hundred seventy-one patients with BAV (n=152) or TAV (n=119) and severe isolated AS without coronary artery disease or other valvular heart disease, scheduled for surgical aortic valve replacement, were prospectively included. Comprehensive preoperative echocardiographic assessment of left ventricular (LV) diastolic and systolic function was performed. The heart failure events were registered during a mean prospective follow-up of 1260 days versus 1441 days for patients with BAV or TAV, respectively.

RESULTS

Patients with BAV had a more pronounced LV hypertrophy with significantly higher indexed LV mass ([LVMi] 134 g/m² versus 104 g/m², P<0.001), higher prevalence of LV diastolic dysfunction (72% versus 44%, P<0.001), reduced LV ejection fraction (55% versus 60%, P<0.001), significantly impaired global longitudinal strain (P<0.001), significantly higher NT-proBNP (N-terminal pro-brain natriuretic peptide) levels (P=0.007), and a higher prevalence of preoperative levosimendan treatment (P<0.001) than patients with TAV. LVMi was associated with diastolic dysfunction in both patients with BAV and TAV. There was a significant interaction between aortic valve morphology and LVMi on LV ejection fraction, which indicated a pronounced association between LVMi and LV ejection fraction for patients with BAV and lack of association between LVMi and LV ejection fraction for patients with TAV. Postoperatively, the patients with BAV required significantly more inotropic support (P<0.001). The patients with BAV had a higher cumulative incidence of postoperative heart failure admissions compared with patients with TAV (28.2% versus 10.6% at 6 years after aortic valve replacement, log-rank P=0.004). Survival was not different between patients with BAV and TAV (log-rank P=0.165).

CONCLUSIONS

Although they were significantly younger, patients with BAV who had isolated severe AS had worse preoperative LV function and an increased risk of postoperative heart failure hospitalization compared with patients who had TAV. Our findings suggest that patients who have BAV with AS might benefit from closer surveillance and possibly earlier intervention.

Transforming growth factor serum concentrations in patients with proven non-syndromic aortopathy

Background

The mechanism underlying aortic dilatation is still unknown. Vascular dilatation is thought to be the result of progressive aortic media degeneration caused by defective vascular matrix hemostasis, including TGF-β1 dysregulation. The goal of this study is to draw attention to the potential utility of TGF-β1 as a diagnostic marker in non-syndromic patients with aortic dilatation.

Methods

TGF-β1 levels in plasma were measured in 50 patients who had undergone surgery and had a tricuspid or bicuspid aortic valve as well as a normal or dilated ascending aorta. A pathologist also examined thirty resected aorta samples. To specify the reference range of TGF-β1, a control group of 40 volunteers was enrolled in this study.

Results

We discovered a significant difference in TGF-β1 levels between patients with aortic dilatation and the control group (32.5 vs. 63.92; P < 0.001), as well as between patients with non-dilated aorta but with aortic valve disease, and the control group (27.68 vs. 63.92; P < 0.001). There was no difference between the dilated ascending aorta group and the non-dilated ascending aorta group. We found a poor correlation between TGF-β1 levels and ascending aorta diameter as well as the grade of ascending aorta histopathological abnormalities.

Conclusion

TGF-β1 concentration does not meet the criteria to be a specific marker of aortic dilatation, but it is sensitive to aortic valvulopathy-aortopathy. A larger patient cohort study is needed to confirm these findings.

Controlled Comparison of Simulated Hemodynamics Across Tricuspid and Bicuspid Aortic Valves

Bicuspid aortic valve is the most common congenital heart defect, affecting 1-2% of the global population. Patients with bicuspid valves frequently develop dilation and aneurysms of the ascending aorta. Both hemodynamic and genetic factors are believed to contribute to dilation, yet the precise mechanism underlying this progression remains under debate. Controlled comparisons of hemodynamics in patients with different forms of bicuspid valve disease are challenging because of confounding factors, and simulations offer the opportunity for direct and systematic comparisons. Using fluid-structure interaction simulations, we simulate flows through multiple aortic valve models in a patient-specific geometry. The aortic geometry is based on a healthy patient with no known aortic or valvular disease, which allows us to isolate the hemodynamic consequences of changes to the valve alone. Four fully-passive, elastic model valves are studied: a tricuspid valve and bicuspid valves with fusion of the left- and right-, right- and non-, and non- and left-coronary cusps. The resulting tricuspid flow is relatively uniform, with little secondary or reverse flow, and little to no pressure gradient across the valve. The bicuspid cases show localized jets of forward flow, excess streamwise momentum, elevated secondary and reverse flow, and clinically significant levels of stenosis. Localized high flow rates correspond to locations of dilation observed in patients, with the location related to which valve cusps are fused. Thus, the simulations support the hypothesis that chronic exposure to high local flow contributes to localized dilation and aneurysm formation.

Reduction ascending aortoplasty: A retrospective analysis of outcomes and risk factors

Objectives

Indication for Reduction of Ascending Aortoplasty (RAA) and long-term outcomes remain unclear. This study analyzed the outcomes after nonreinforced RAA in two Austrian centers.

Methods

Patients with RAA at two Austrian centers between 6/2,009 and 6/2,017 were retrospectively analyzed. Aortic diameters were measured by CT pre- and post-operatively. Patients were assigned according to valve morphology and imaging modality.

Results

Overall, 253 patients underwent RAA [women: 30.8%; median age 74 (63–79) years] with a mean preoperative ascending diameter of 44.7 (±3.5) mm. RAA-related postoperative adverse events occurred in 1.2% (n = 3) over a follow-up of a median of 3.8 (2.4–5.5) years: One type A aortic dissection, one lethal aortic rupture at the suture line, and one suture line bleeding with cardiac tamponade and need of surgical revision. The overall survival rate was 89.7%. Aortic valve morphology itself was no risk factor for mortality (Log-Rank: 0.942). One hundred and forty patients had a tricuspid [TAV: (55.3%)] aortic valve and 113 patients had a bicuspid aortic valve [BAV: (44.7%)]. Redilatation to a diameter >50 mm according to CT follow-up occurred in 5.7% (n = 5 of 87). One patient needed reoperation with RAA and aortic valve replacement due to a prosthesis-patient mismatch after aortic valve replacement and aortic redilatation.

Conclusion

Non-reinforced RAA is a safe, feasible, and reproducible procedure with low rates of perioperative complications in selected patients primarily undergoing aortic valve repair with a dilated ascending aorta. Aortic valve morphology has no impact on mortality after RAA.

Feasibility of a longitudinal statistical atlas model to study aortic growth in congenital heart disease

Studying anatomical shape progression over time is of utmost importance to refine our understanding of clinically relevant processes. These include vascular remodeling, such as aortic dilation, which is particularly important in some congenital heart defects (CHD). A novel methodological framework for three-dimensional shape analysis has been applied for the first time in a CHD scenario, i.e., bicuspid aortic valve (BAV) disease, the most common CHD. Three-dimensional aortic shapes (n = 94) reconstructed from cardiovascular magnetic resonance imaging (MRI) data as surface meshes represented the input for a longitudinal atlas model, using multiple scans over time (n = 2-4 per patient). This model relies on diffeomorphism transformations in the absence of point-to-point correspondence, and on the right combination of initialization, estimation and registration parameters. We computed the shape trajectory of an average disease progression in our cohort, as well as time-dependent parameters, geometric variations and the average shape of the population. Results cover a spatiotemporal spectrum of visual and numerical information that can be further used to run clinical associations. This proof-of-concept study demonstrates the feasibility of applying advanced statistical shape models to track disease progression and stratify patients with CHD.

Assessment of Paravalvular Leak Severity and Thrombogenic Potential in Transcatheter Bicuspid Aortic Valve Replacements Using Patient-Specific Computational Modeling

Bicuspid aortic valve (BAV), the most common congenital valvular abnormality, generates asymmetric flow patterns and increased stresses on the leaflets that expedite valvular calcification and structural degeneration. Recently adapted for use in BAV patients, TAVR demonstrates promising performance, but post-TAVR complications tend to get exacerbated due to BAV anatomical complexities. Utilizing patient-specific computational modeling, we address some of these complications. The degree and location of post-TAVR PVL was assessed, and the risk of flow-induced thrombogenicity was analyzed in 3 BAV patients - using older generation TAVR devices that were implanted in these patients, and compared them to the performance of the newest generation TAVR devices using in silico patient models. Significant decrease in PVL and thrombogenic potential was observed after implantation of the newest generation device. The current work demonstrates the potential of using simulations in pre-procedural planning to assess post-TAVR complications, and compare the performance of different devices to achieve better clinical outcomes. Patient-specific computational framework to assess post-transcatheter bicuspid aortic valve replacement paravalvular leakage and flow-induced thrombogenic complications and compare device performances.

Design considerations for engineering 3D models to study vascular pathologies in vitro

Many cardiovascular diseases (CVD) are driven by pathological remodelling of blood vessels, which can lead to aneurysms, myocardial infarction, ischaemia and strokes. Aberrant remodelling is driven by changes in vascular cell behaviours combined with degradation, modification, or abnormal deposition of extracellular matrix (ECM) proteins. The underlying mechanisms that drive the pathological remodelling of blood vessels are multifaceted and disease specific; however, unravelling them may be key to developing therapies. Reductionist models of blood vessels created in vitro that combine cells with biomaterial scaffolds may serve as useful analogues to study vascular disease progression in a controlled environment. This review presents the main considerations for developing such in vitro models. We discuss how the design of blood vessel models impacts experimental readouts, with a particular focus on the maintenance of normal cellular phenotypes, strategies that mimic normal cell-ECM interactions, and approaches that foster intercellular communication between vascular cell types. We also highlight how choice of biomaterials, cellular arrangements and the inclusion of mechanical stimulation using fluidic devices together impact the ability of blood vessel models to mimic in vivo conditions. In the future, by combining advances in materials science, cell biology, fluidics and modelling, it may be possible to create blood vessel models that are patient-specific and can be used to develop and test therapies. STATEMENT OF SIGNIFICANCE: Simplified models of blood vessels created in vitro are powerful tools for studying cardiovascular diseases and understanding the mechanisms driving their progression. Here, we highlight the key structural and cellular components of effective models and discuss how including mechanical stimuli allows researchers to mimic native vessel behaviour in health and disease. We discuss the primary methods used to form blood vessel models and their limitations and conclude with an outlook on how blood vessel models that incorporate patient-specific cells and flows can be used in the future for personalised disease modelling.

Family screening in patients with isolated bicuspid aortic valve : Restriction to those with aortic dilatation is not justified

Aim

To determine the prevalence of undiagnosed bicuspid aortic valve (BAV) and isolated aortic dilatation in first-degree relatives (FDRs) of patients with isolated BAV and to explore the recurrence risk of BAV in different subgroups of probands with BAV. Recent American College of Cardiology (ACC)/American Heart Association (AHA) Guidelines recommend family screening in patients with associated aortopathy only.

Methods

During follow-up visits, patients with isolated BAV received a printed invitation for their FDRs advising cardiac screening.

Results

From 2012–2019, 257 FDRs of 118 adult BAV patients were screened, among whom 63 (53%) index patients had undergone aortic valve surgery (AVS), including concomitant aortic replacement in 25 (21%). Of the non-operated index patients, 31 (26%) had aortic dilatation (> 40 mm). Mean age of the FDRs was 48 years (range 4–83) and 42% were male. The FDR group comprised 20 parents, 103 siblings and 134 offspring. Among these FDRs, 12 (4.7%) had a previously undiagnosed BAV and 23 (8.9%) had an isolated aortic dilatation. FDRs of the probands with previous AVS (n = 147) had a risk ratio for BAV of 2.25 (95% confidence interval (CI) 0.62–8.10). FDRs of the probands with BAV and repaired or unrepaired aortic dilatation (n = 127) had a risk ratio for BAV of 0.51 (95% CI 0.16–1.66).

Conclusion

Screening FDRs of patients with isolated BAV resulted in a reasonable yield of 14% new cases of BAV or isolated aortic dilatation. A trend towards an increased risk of BAV in FDRs was observed in the probands with previous AVS, whereas this risk seemed to be diminished in the probands with associated aortic dilatation. This latter finding does not support the restrictive ACC/AHA recommendation.

Temporal Trends and Outcomes of Elective Thoracic Aortic Repair and Acute Aortic Syndromes in Bicuspid Aortic Valves: Insights from a National Database

Introduction

There is paucity of data on the outcomes of hospitalization for bicuspid aortic valve (BAV)-related aortopathies.

Methods

We queried the NIS database (2012–2016) for hospitalizations for elective thoracic aortic repair or acute aortic syndrome (AAS) among those with BAV versus trileaflet aortic valve (TAV).

Results

Our analysis yielded 38,010 hospitalizations for elective aortic repair, of whom 34.4% had BAV, as well as 81,875 hospitalizations for thoracic AAS, of whom 1.1% had BAV. Hospitalizations for BAV were younger and had fewer comorbidities compared with their TAV counterparts. The number of hospitalizations for BAV during the observational period was unchanged. After propensity matching, elective aortic repair for BAV was associated with lower mortality (0.5% versus 1.7%, odds ratio = 0.28; 95% CI 1.5–0.50, p < 0.001), use of mechanical circulatory support, acute stroke, and shorter length of hospital stay compared with TAV. After propensity matching, AAS among those with BAV had a greater incidence of bleeding events, blood transfusion, cardiac tamponade, ventricular arrhythmias, and a longer length of hospital stay compared with TAV. Among those with BAV, predictors of lower mortality if undergoing elective aortic repair included larger hospitals and teaching hospitals. Predictors of higher mortality in patients with AAS included heart failure, chronic kidney disease, and coronary artery disease.

Conclusion

Data from a national database showed no change in the number of hospitalizations for BAV-related aortopathy, with relatively lower incidence of AAS. Compared with TAV, elective aortic repair for BAV is associated with lower mortality, while BAV-related AAS is associated with higher in-hospital complications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40119-021-00237-3.

Advanced cardiovascular multimodal imaging and aortic stenosis

Aortic valve stenosis has become the most common valvular heart disease on account of aging population and increasing life expectancy. Echocardiography is the primary diagnosis tool for this, but it still has many flaws. Therefore, advanced cardiovascular multimodal imaging techniques are continuously being developed in order to overcome these limitations. Cardiac magnetic resonance imaging (CMR) allows a comprehensive morphological and functional evaluation of the aortic valve and provides important data for the diagnosis and risk stratification in patients with aortic stenosis. CMR can functionally assess the aortic flow using two-dimensional and time-resolved three-dimensional velocity-encoded phase-contrast techniques. Furthermore, by late gadolinium enhancement and T1-mapping, CMR can reveal the presence of both irreversible replacement and diffuse interstitial myocardial fibrosis. Moreover, its role in guiding aortic valve replacement procedures is beginning to take shape. Recent studies have rendered the importance of active and passive biomechanics in risk stratification and prognosis prediction in patients with aortic stenosis, but more work is required is just in its infancy, but data are promising. In addition, cardiac computed tomography is particularly useful for the diagnosis of aortic valve stenosis, and in preprocedural evaluation of the aorta, while positron emission tomography can be also used to assess valvular inflammation and active calcification. The purpose of this review is to provide a comprehensive overview of current available data regarding advanced cardiovascular multimodal imaging in aortic stenosis.

Monocyte-to-HDL-cholesterol ratio is associated with Ascending Aorta Dilatation in Patients with Bicuspid Aortic Valve

BACKGROUND

The importance of monocyte count-to-HDL-cholesterol ratio (MHR) in cardio- vascular diseases has been shown in various studies. Ascending aortic dilatation (AAD) is a common complication in the patients with bicuspid aortic valve. In this study, we aimed to investigate the relationship between MHR and the presence of aortic dilatation in the patients with bicuspid aortic valve.

METHODS

The study population included totally 347 patients with bicuspid aortic valve.169 patients with aortic dilatation (ascending aorta diameter ≥ 4.0 cm) and 178 patients with no aortic dilatation. Echocardiographic and laboratory measurement was done and compared between groups.

RESULTS

The mean age of the participants was 44.7 ± 15.4 years and average ascending aorta diameter was 3.2 ± 0.3 cm in dilatation negative group and 4.4 ± 0.4 cm in positive group. MHR was significantly increased in in patients with aortic dilatation. MHR and uric acid level was independently associated with the presence of aortic dilatation in the patients with bicuspid aortic valve.

CONCLUSION

We found a significant relationship between MHR and aortic dilatation in the patients with bicuspid aortic valve.

Prevalence of Bicuspid Aortic Valve and Associated Aortopathy in Newborns in Copenhagen, Denmark

IMPORTANCE

The prevalence and characteristics of bicuspid aortic valve (BAV) are mainly reported from selected cohorts. BAV is associated with aortopathy, but it is unclear if it represents a fetal developmental defect or is secondary to abnormal valve dynamics.

OBJECTIVE

To determine the prevalence of BAV and BAV subtypes and to describe the associated aortopathy in a large, population-based cohort of newborns.

DESIGN, SETTING, AND PARTICIPANTS

The Copenhagen Baby Heart Study was a cross-sectional, population-based study open to all newborns born in Copenhagen between April 1, 2016, and October 31, 2018. Newborns with BAV were matched 1:2 to newborns with a tricuspid aortic valve (non-BAV group) on sex, singleton/twin pregnancy, gestational age, weight, and age at time of examination.

EXPOSURES

Transthoracic echocardiography within 60 days after birth.

MAIN OUTCOMES AND MEASURES

Primary outcome was BAV prevalence and types, ie, number of raphes and spatial orientation of raphes or cusps (no raphes), according to the classification system of Sievers and Schmidtke (classified as type 0, 1, or 2, with numbers indicating the number of raphes). Secondary outcome was valve function and BAV-associated aortopathy, defined as aortic diameter z score of 3 or greater or coarctation.

RESULTS

In total, 25 556 newborns (51.7% male; mean age, 12 [SD, 8] days) underwent echocardiography. BAV was diagnosed in 196 newborns (prevalence, 0.77% [95% CI, 0.67%-0.88%]), with male-female ratio 2.1:1. BAV was classified as type 0 in 17 newborns (8.7% [95% CI, 5.5%-13.5%]), type 1 in 178 (90.8% [95% CI, 86.0%-94.1%]) (147 [75.0% {95% CI, 68.5%-80.5%}] right-left coronary raphe, 27 [13.8% {95% CI, 9.6%-19.3%}] right coronary-noncoronary raphe, 4 [2.0% {95% CI, 0.8%-5.1%}] left coronary-noncoronary raphe), and type 2 in 1 (0.5% [95% CI, 0.1%-2.8%]). Aortic regurgitation was more prevalent in newborns with BAV (n = 29 [14.7%]) than in those without BAV (1.3%) (absolute % difference, 13.4% [95% CI, 7.8%-18.9%]; P < .001). Newborns with BAV had higher flow velocities across the valve (0.67 [95% CI, 0.65-0.69] m/s vs 0.61 [95% CI, 0.60-0.62] m/s; mean difference, 0.06 m/s [95% CI, 0-0.1]) and larger aortic root and tubular ascending aortic diameters than those without BAV (10.7 [95% CI, 10.7-10.9] mm vs 10.3 [95% CI, 10.2-10.4] mm; mean difference, 0.43 mm [95% CI, 0.2-0.6 mm] and 9.8 [95% CI, 9.6-10.0] mm vs 9.4 [95% CI, 9.3-9.5] mm; mean difference, 0.46 mm [95% CI, 0.30-0.70], respectively) (P < .001 for all). Aortopathy was seen in 65 newborns (33.2%) with BAV (62 with aortic z score ≥3; 3 with coarctation).

CONCLUSIONS AND RELEVANCE

Among newborns in Copenhagen, the prevalence of BAV was 0.77%. Aortopathy was common in newborns with BAV, suggesting that it also represents a fetal malformation.

Patients with bicuspid aortic valves may be associated with infra-hisian conduction disease requiring pacemakers

BACKGROUND

Bicuspid aortic valves (BAVs) are associated with accelerated valvular dysfunction. Increasing rates of conduction system disease are seen in patients with calcific tricuspid aortic valves (TAVs). However, little is known regarding the extent of conduction disorders in BAV patients. We sought to determine the extent of infra-hisian conduction pathology among patients with BAVs undergoing EP studies.

METHODS

We prospectively analyzed patients presenting to the EP laboratory from 2006 to 2017 at our institution. Thirty-three BAV patients had measured HV intervals. Each individual was matched by age and gender to two control patients. Clinical characteristics were collected and compared, and patients followed for outcomes.

RESULTS

The BAV cohort had a mean age of 47.8 ± 17.2 years (range 19-76 years). Indications for referral to the EP lab in the BAV cohort included SVT ablation (n = 16), VT ablation (n = 10), and EP study for syncope, pre-syncope, or palpitations (n = 29). Patients with BAVs had a mean HV interval of 58.7 ms ± 18.6 ms, compared to a mean of 47.2 ms ± 9.6 ms for controls (p value = 0.0001). Over a 10-year follow-up period, 9 BAV patients (27%) went on to require permanent pacing compared to 6 patients (9%) in the control group (p value = 0.03).

CONCLUSION

Compared to patients with TAVs presenting for EP evaluation, individuals with BAVs have longer HV intervals and a significantly increased requirement for pacemaker therapy over long-term follow-up. Closer monitoring of progressive conduction system disease in BAV patients may be warranted.

Targetable cellular signaling events mediate vascular pathology in vascular Ehlers-Danlos syndrome

Vascular Ehlers-Danlos syndrome (vEDS) is an autosomal-dominant connective tissue disorder caused by heterozygous mutations in the COL3A1 gene, which encodes the pro-α 1 chain of collagen III. Loss of structural integrity of the extracellular matrix is believed to drive the signs and symptoms of this condition, including spontaneous arterial dissection and/or rupture, the major cause of mortality. We created 2 mouse models of vEDS that carry heterozygous mutations in Col3a1 that encode glycine substitutions analogous to those found in patients, and we showed that signaling abnormalities in the PLC/IP3/PKC/ERK pathway (phospholipase C/inositol 1,4,5-triphosphate/protein kinase C/extracellular signal-regulated kinase) are major mediators of vascular pathology. Treatment with pharmacologic inhibitors of ERK1/2 or PKCβ prevented death due to spontaneous aortic rupture. Additionally, we found that pregnancy- and puberty-associated accentuation of vascular risk, also seen in vEDS patients, was rescued by attenuation of oxytocin and androgen signaling, respectively. Taken together, our results provide evidence that targetable signaling abnormalities contribute to the pathogenesis of vEDS, highlighting unanticipated therapeutic opportunities.

Determinants of aortic growth rate in patients with bicuspid aortic valve by cardiovascular magnetic resonance

Objectives

This study aimed to identify determinants of aortic growth rate in bicuspid aortic valve (BAV) patients. We hypothesised that (1) BAV patients with repaired coarctation (CoA) exhibit decreased aortic growth rate, (2) moderate/severe re-coarctation (reCoA) results in increased growth rate, (3) patients with right non-coronary (RN) valve cusps fusion pattern exhibit increased aortic growth rate compared with right-left cusps fusion and type 0 valves.

Methods

Starting from n=521 BAV patients with cardiovascular magnetic resonance data, we identified n=145 patients with at least two scans for aortic growth analysis. Indexed areas of the sinuses of Valsalva and ascending aorta (AAo) were calculated from cine images in end-systole and end-diastole. Patients were classified based on dilation phenotype, presence of CoA, aortic valve function and BAV morphotype. Comparisons between groups were performed. Linear regression was carried out to identify associations between risk factors and aortic growth rate.

Results

Patients (39±16 years of age, 68% male) had scans 3.7±1.8 years apart; 32 presented with AAo dilation, 18 with aortic root dilation and 32 were overall dilated. Patients with repaired CoA (n=61) showed decreased aortic root growth rate compared with patients without CoA (p≤0.03) regardless of sex or age. ReCoA, aortic stenosis, regurgitation and history of hypertension were not associated with growth rate. RN fusion pattern showed the highest aortic root growth rate and type 0 the smallest (0.30 vs 0.08 cm²/m*year, end-systole, p=0.03).

Conclusions

Presence of CoA and cusp fusion morphotype were associated with changes in rate of root dilation in our BAV population.

Bicuspid valve aortopathy is associated with distinct patterns of matrix degradation

OBJECTIVE

To explore the micromechanical, biochemical, and microstructural differences between bicuspid aortic valve aneurysm (BAV-A) and tricuspid aortic valve idiopathic degenerative aneurysm (DA), compared with normal aorta.

METHODS

Aortic tissue was obtained from patients undergoing aneurysmal repair surgery (BAV-A; n = 15 and DA; n = 15). Control tissue was obtained from aortic punch biopsies during coronary artery bypass graft surgery (n = 9). Nanoindentation was used to determine the elastic modulus on the medial layer. Glycosaminoglycan, collagen, and elastin levels were measured using biochemical assays. Verhoeff Van Gieson-stained cross-sections were imaged for elastin microstructural quantification.

RESULTS

The elastic modulus was more than 20% greater for BAV-A relative to control and DA (signifying a loss of compliance). No significance difference between control and DA were observed. Collagen levels for BAV-A (36.9 ± 7.4 μg/mg) and DA (49.9 ± 10.9 μg/mg) were greater compared with the control (30.2 ± 13.1 μg/mg). Glycosaminoglycan and elastin levels were not significant between the groups. Elastin segments were uniform throughout the control. Aneurysmal tissues had less elastin segments close to the intima and adventitia layers. Both BAV-A and DA had elastin segments compacted in the media; however, elastin segments were highly fragmented in DA.

CONCLUSIONS

BAV-A has a greater loss of aortic wall compliance relative to DA and the control. Although elastin levels were equal for all groups, spatial distribution of elastin provided a unique profile of matrix degradation for BAV-A. Elastin compaction within the media of BAV-A may have resulted from the altered hemodynamic pressure against the wall, which could explain for the stiffness of the tissue.

High prevalence of ascending aortic dilatation in a consecutive coronary CT angiography patient population

Objectives

To clarify the prevalence and risk factors of ascending aortic (AA) dilatation according to ESC 2014 guidelines.

Methods

This study included 1000 consecutive patients scheduled for diagnostic coronary artery computed tomographic angiography. AA diameter was retrospectively measured in 3 planes: sinus valsalva, sinotubular junction, and tubular part. The threshold for AA dilatation was set to > 40 mm which has been suggested as an upper normal limit for AA diameter in ESC 2014 guidelines on aortic diseases. Aortic size index (ASI) using the ratio between aortic diameter and body surface area (BSA) was applied as a comparative measurement. The threshold for AA dilatation was set to the upper limit of normal distribution exceeding two standard deviations (95%). Risk factors for AA dilatation were collected from medical records.

Results

The patients’ mean age was 52.9 ± 9.8 years (66.5% women). The prevalence of AA dilatation was 23.0% in the overall study population (52.5% males) and 15.1% in the subgroup of patients with no coronary artery disease or bicuspid (BAV)/mechanical aortic valve (n = 365). According to the normal-distributed ASI values, the threshold for sinus valsalva was defined as 23.2 mm/m² and for tubular part 22.2 mm/m² in the subgroup. Higher BSA was associated with larger AA dimensions (r = 0.407, p < 0.001). Male gender (p < 0.001), BAV (p < 0.001), hypertension (p = 0.009) in males, and smoking (p < 0.001) appeared as risk factors for AA dilatation.

Conclusions

The prevalence of AA dilatation is high with current ESC guidelines for normal AA dimension, especially in males. Body size is strongly associated with AA dimensions; it would be more reliable to use BSA-adjusted AA diameters for the definition of AA dilatation.

Key Points

• The prevalence of AA dilatation is high in patients who are candidates for coronary CT angiography.

• Body size is strongly associated with AA dimensions.

microRNAs in bicuspid aortic valve associated aortopathy: Recent advances and future perspectives

The risk of acute aortic events in patients with bicuspid aortic valve (BAV) constitutes a medical concern in terms of timing and surgical decision. During the past years, there has been a growing interest in the potential of microRNAs (miRNAs) as crucial epigenetic factors in multiple cellular processes associated with BAV aortopathy. Nevertheless, there are still challenges that need to be overcome before miRNAs could enter clinical practice, and further validation studies in larger and well-defined BAV cohorts are now required. This review aims at providing a comprehensive overview of the available data on the expression profiles and function of specific miRNAs in BAV aortopathy, evaluating miRNA signatures as potential molecular markers of disease. We also discuss the role of other novel classes of non-coding RNAs, including long non-coding RNAs and circular RNAs, in BAV-associated aortopathy, mainly regarding their possible implementation as diagnostic and prognostic markers.

Risk Factors Associated with Ascending Aortic Aneurysms and Aortic Elasticity Parameters in Children with a Bicuspid Aortic Valve

Aneurysms of the ascending aorta are frequently found in patients with a bicuspid aortic valve (BAV). This study assessed the risk factors of ascending aortic aneurysms and aortic elasticity in children with BAV. The study included 66 patients with no history of transcatheter intervention or surgical procedure who had been diagnosed with isolated BAV. Echocardiographic, blood pressure, and pulse measurements were obtained for all patients. The BAVs were classified as described by Sievers et al. (J Thorac Cardiovasc Surg 133:1226-1233, 2007), and aortic elasticity parameters were calculated using various formulas. The patients were divided into groups with and without cusp fusion, aortic stenosis (AS), aortic regurgitation (AR), or mixed lesions; the groups were then compared. The mean patient age was 10.43 ± 3.91 years; 15%he patients had no AS or AR, 33% had both AS and AR, 17% had AS alone, and 35% had AR alone. The most common type of BAV was type 5, and the ascending aorta z-scores were higher in children with mixed lesions and without a cusp fusion. Aortic distensibility (AD) was significantly higher, and the stiffness index was significantly lower, in patients with an ascending aorta z-score > 4. The ascending aortic z-scores were higher in the no-fusion and mixed lesion (AS + AR) groups, especially those originating from post-stenotic dilation due to AS. The AD was increased in patients with an ascending aorta z-score > 4. Patients should thus be monitored closely for dissection risk, and preventive medical treatment should be started early in those with AS without cusp fusion.

Clinical-pathological correlations of BAV and the attendant thoracic aortopathies. Part 1: Pluridisciplinary perspective on their hemodynamics and morphomechanics

Clinical BAV manifestations pertain to faulty aortic valve (AOV) function, the associated aortopathy, and other complications such as endocarditis, thrombosis and thromboembolism. BAV arises during valvulogenesis when 2 of the 3 leaflets/cusps of the AOV are fused together. Ensuing asymmetric BAV morphologies alter downstream ejection jet flow-trajectories. Based on BAV morphologies, ejection-flows exhibit different wall-impingement and scouring patterns in the proximal aorta, with excessive hydrodynamic wall-shear that correlates closely with mural vascular smooth muscle cell and extracellular matrix disruptions, revealing hemodynamic participation in the pathogenesis of BAV-associated aortopathies. Since the embryologic regions implicated in both BAV and aortopathies derive from neural crest cells and second heart field cells, there may exist a common multifactorial/polygenic embryological basis linking the abnormalities. The use of Electronic Health Records - encompassing integrated NGS variant panels and phenotypic data - in clinical studies could speed-up comprehensive understanding of multifactorial genetic-phenotypic and environmental factor interactions. This Survey represents the first in a 2-article pluridisciplinary work. Taken in toto, the series covers hemodynamic/morphomechanical and environmental (milieu intérieur) aspects in Part 1, and molecular, genetic and associated epigenetic aspects in Part 2. Together, Parts 1-2 should serve as a reference-milestone and driver for further pluridisciplinary research and its urgent translations in the clinical setting.

Bicuspid Aortic Valve Alters Aortic Protein Expression Profile in Neonatal Coarctation Patients

Coarctation of the aorta is a form of left ventricular outflow tract obstruction in paediatric patients that can be presented with either bicuspid (BAV) or normal tricuspid (TAV) aortic valve. The congenital BAV is associated with hemodynamic changes and can therefore trigger different molecular remodelling in the coarctation area. This study investigated the proteomic and phosphoproteomic changes associated with BAV for the first time in neonatal coarctation patients. Aortic tissue was collected just proximal to the coarctation site from 23 neonates (BAV; n = 10, TAV; n = 13) that were matched for age (age range 4-22 days). Tissue from half of the patients was frozen and used for proteomic and phosphoproteomic analysis whilst the remaining tissue was formalin fixed and used for analysis of elastin content using Elastic Van-Gieson (EVG) staining. A total of 1796 protein and 75 phosphoprotein accession numbers were detected, of which 34 proteins and one phosphoprotein (SSH3) were differentially expressed in BAV patients compared to TAV patients. Ingenuity Pathway Analysis identified the formation of elastin fibres as a significantly enriched function (p = 1.12 × 10^-4) due to the upregulation of EMILIN-1 and the downregulation of TNXB. Analysis of paraffin sections stained with EVG demonstrated increased elastin content in BAV patients. The proteomic/phosphoproteomic analysis also suggested changes in inositol signalling pathways and reduced expression of the antioxidant SOD3. This work demonstrates for the first time that coarcted aortic tissue in neonatal BAV patients has an altered proteome/phosphoproteome consistent with observed structural vascular changes when compared to TAV patients.

Extracellular matrix in ascending aortic aneurysms and dissections - What we learn from decellularization and scanning electron microscopy

Pathological impairment of elastic fiber and other extracellular matrix (ECM) components are described for the aortic media of ascending thoracic aortic aneurysms (aTAA) but the exact pathological impairment of the structure and its degree still needs further investigations. To evaluate the quantity and quality of elastic fiber sheets and other ECM structures (e.g. collagen), cells were removed from different types of aneurysmal tissues (tricuspid aortic valve [TAV] associated-, bicuspid aortic valve [BAV] associated-aneurysmal tissue and acute aortic dissections [AAD]) using 2.5% sodium hydroxide (NaOH) and compared to decellularized control aortic tissue. Likewise, native tissue has been analysed. To evaluate the 2D- (histological evaluation, fluorescence- and auto-fluorescence based staining methods) and the 3D structure (scanning electron microscopic [SEM] examination) of the medial layer we first analysed for a successful decellularization. After proving for successful decellularization, we quantified the amount of elastic fiber sheets, elastin and other ECM components including collagen. Aside from clearly visible focal elastic fiber loss in TAV-aTAA tissue, decellularization resulted in reduction of elastic fiber auto-fluorescence properties, which is perhaps an indication from a disease-related qualitative impairment of elastic fibers, visible only after contact with the alkaline solution. Likewise, the loss of collagen amount in BAV-aTAA and TAV-aTAA tissue (compared to non-decellularized tissue) after contact with NaOH indicates a prior disease-associated impairment of collagen. Although the amount of ECM was not changed in type A dissection tissue, detailed electron microscopic evaluation revealed changes in ECM quality, which worsened after contact with alkaline solution but were not visible after histological analyses. Apart from the improved observation of the samples using electron microscopy, contact of aneurysmal and dissected tissue with the alkaline decellularization solution revealed potential disease related changes in ECM quality which can partly be connected to already published data, but have to be proven by further studies.

Unicuspid aortic valve replacement with development of complete heart block: a case report

BACKGROUND

Aortic stenosis is a progressive disease that frequently remains undiagnosed until late in the disease course. In patients that present with symptoms of heart failure and a systolic murmur at a young age, a congenital valvular abnormality must be on the differential. With patients that have accelerated symptoms of aortic stenosis and valvular dysfunction, a unicuspid aortic valve (UAV) could be present. A UAV is often difficult to distinguish from a bicuspid aortic valve (BAV) on transthoracic echocardiography. In patients with congenital valvular abnormalities an ascending aortic aneurysm can also be present. Aortic stenosis changes the jet of fluid emerging from the aortic valve leading to an increased risk for aortic aneurysm dissection and rupture. The gold standard treatment for aortic stenosis secondary to a congenital valvular abnormality is valve replacement. A known risk of aortic valve replacement is conduction abnormalities. In this case, we present a patient with a unicuspid valve who postoperatively develops complete heart block leading to pacemaker implantation.

CASE SUMMARY

We present a case of a 46-year-old Caucasian male with no prior medical history who presented with progressively worsening exertional dyspnoea and palpitations for 7 months. Transthoracic echocardiogram showed a BAV, however, further work up confirmed a unicommissural aortic valve with severe aortic stenosis and moderate regurgitation along with an ascending aortic aneurysm. Aortic valve replacement and aortic aneurysm repair via the Bentall procedure was successfully completed with postoperative course being complicated by a complete heart block and subsequent permanent pacemaker placement.

DISCUSSION

When assessing patients with symptoms of heart failure with a systolic murmur that suggests aortic stenosis at a young age, a UAV must be kept on the differential. The symptoms of aortic stenosis and valvular dysfunction are accelerated in UAVs when compared with BAVs. Currently, the treatment for patients with congenital valvular abnormalities presenting with aortic stenosis is aortic valve replacement using traditional open surgery. A known sequelae of isolated aortic valve replacement is conduction abnormalities that can sometimes lead to permanent pacemaker placement. After the confirmation of unicuspid or bicuspid valve postoperatively, it is important to report any postoperative conduction abnormalities. This is because, currently, there is no literature that compares the incidence of conduction abnormalities after unicuspid replacement to that of other BAV syndromes.

Wall Shear Stress Directional Abnormalities in BAV Aortas: Toward a New Hemodynamic Predictor of Aortopathy?

The bicuspid aortic valve (BAV) generates wall shear stress (WSS) abnormalities in the ascending aorta (AA) that may be responsible for the high prevalence of aortopathy in BAV patients. While previous studies have analyzed the magnitude and oscillatory characteristics of the total or streamwise WSS in BAV AAs, the assessment of the circumferential component is lacking despite its expected significance in this highly helical flow environment. This gap may have hampered the identification of a robust hemodynamic predictor of BAV aortopathy. The objective of this study was to perform a global and component-specific assessment of WSS magnitude, oscillatory and directional characteristics in BAV AAs. The WSS environments were computed in the proximal and middle convexity of tricuspid aortic valve (TAV) and BAV AAs using our previous valve-aorta fluid-structure interaction (FSI) models. Component-specific WSS characteristics were investigated in terms of temporal shear magnitude (TSM) and oscillatory shear index (OSI). WSS directionality was quantified in terms of mean WSS vector magnitude and angle, and angular dispersion index (D_α). Local WSS magnitude and multidirectionality were captured in a new shear magnitude and directionality index (SMDI) calculated as the product of the mean WSS magnitude and D_α. BAVs subjected the AA to circumferential TSM overloads (2.4-fold increase vs. TAV). TAV and BAV AAs exhibited a unidirectional circumferential WSS (OSI < 0.04) and an increasingly unidirectional longitudinal WSS between the proximal (OSI > 0.21) and middle (OSI < 0.07) sections. BAVs generated mean WSS vectors skewed toward the anterior wall and WSS angular distributions exhibiting decreased uniformity in the proximal AA (0.27-point increase in D_α vs. TAV). SMDI was elevated in all BAV AAs but peaked in the proximal LR-BAV AA (3.6-fold increase vs. TAV) and in the middle RN-BAV AA (1.6-fold increase vs. TAV). This analysis demonstrates the significance of the circumferential WSS component and the existence of substantial WSS directional abnormalities in BAV AAs. SMDI abnormality distributions in BAV AAs follow the morphotype-dependent occurrence of dilation in BAV AAs, suggesting the predictive potential of this metric for BAV aortopathy.

Age-related changes of shape and flow dynamics in healthy adult aortas: A 4D flow MRI study

BACKGROUND

Abnormal flow dynamics play an early and causative role in pathologic changes of the ascending aorta.

PURPOSE

To identify: 1) the changes in flow, shape, and size that occur in the ascending aorta with normal human ageing and 2) the influence of these factors on aortic flow dynamics.

STUDY TYPE

Retrospective.

SUBJECTS

In all, 247 subjects (age range 19-86 years, mean 49 ± 17.7, 169 males) free of aortic or aortic valve pathology were included in this study. Subjects were stratified by youngest (18-33 years; n = 64), highest (>60 years, n = 67), and the middle two quartiles (34-60 years, n = 116).

FIELD STRENGTH/SEQUENCE

Subjects underwent a cardiac MRI (3T) exam including 4D-flow MRI of the aorta.

ASSESSMENT

Aortic curvature, arch shape, ascending aortic angle, ascending aortic diameter, and the stroke volume normalized by the aortic volume (nSV) were measured. Velocity, vorticity, and helicity were quantified across the thoracic aorta.

STATISTICAL TESTS

Univariate and multivariate regressions were used to quantify continuous relationships between variables.

RESULTS

Aortic diameter, ascending aortic angle, shape, and curvature all increased across age while nSV decreased (all P < 0.0001). Systolic vorticity in the mid arch decreased by 50% across the age range (P < 0.0001), while peak helicity decreased by 80% (P < 0.0001). Curvature tightly governs optimal flow in the youngest quartile, with an effect size 1.5 to 4 times larger than other parameters in the descending aorta, but had a minimal influence with advancing age. In the upper quartile of age, flow dynamics were almost completely determined by nSV, exerting an effect size on velocity and vorticity >10 times that of diameter and other shape factors.

DATA CONCLUSION

Aortic shape influences flow dynamics in younger subjects. Flow conditions become increasingly disturbed with advancing age, and in these conditions nSV has a more dominant effect on flow patterns than shape factors.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:90-100.

Induced pluripotent stem cells with NOTCH1 gene mutation show impaired differentiation into smooth muscle and endothelial cells: Implications for bicuspid aortic valve-related aortopathy

OBJECTIVE

The NOTCH1 gene mutation has been identified in bicuspid aortic valve patients. We developed an in vitro model with human induced pluripotent stem cells (iPSCs) to evaluate the role of NOTCH1 in smooth muscle and endothelial cell (EC) differentiation.

METHODS

The iPSCs were derived from a patient with a normal tricuspid aortic valve and aorta. The NOTCH1 gene was targeted in iPSCs with the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 nuclease (Cas9) system. The NOTCH1^-/- (NOTCH1 homozygous knockout) and isogenic control iPSCs (wild type) were differentiated into neural crest stem cells (NCSCs) and into cardiovascular progenitor cells (CVPCs). The NCSCs were differentiated into smooth muscle cells (SMCs). The CVPCs were differentiated into ECs. The differentiations of SMCs and ECs were compared between NOTCH1^-/- and wild type cells.

RESULTS

The expression of NCSC markers (SRY-related HMG-box 10 and transcription factor AP-2 alpha) was significantly lower in NOTCH1^-/-NCSCs than in wild type NCSCs. The SMCs derived from NOTCH1^-/- NCSCs showed immature morphology with smaller size and decreased expression of all SMC-specific contractile proteins. In NOTCH1^-/-CVPCs, the expression of ISL1, NKX2.5, and MYOCD was significantly lower than that in isogenic control CVPCs, indicating impaired differentiation from iPSCs to CVPCs. The NOTCH1^-/-ECs derived from CVPCs showed significantly lower expression of cluster of differentiation 105 and cluster of differentiation 31 mRNA and protein, indicating a defective differentiation process.

CONCLUSIONS

NOTCH1 is critical in SMC and EC differentiation of iPSCs through NCSCs and CVPCs, respectively. NOTCH1 gene mutations might potentially contribute to the development of thoracic aortic aneurysms by affecting SMC differentiation in some patients with bicuspid aortic valve.

Non-coding RNAs in aneurysmal aortopathy

Aortic aneurysms represent a major public health burden, and currently have no medical treatment options. The pathophysiology behind these aneurysms is complex and variable, depending on location and underlying cause, and generally involves progressive dysfunction of all elements of the aortic wall. Changes in smooth muscle behavior, endothelial signaling, extracellular matrix remodeling, and to a variable extent inflammatory signaling and cells, all contribute to the dilation of the aorta, ultimately resulting in high mortality and morbidity events including dissection and rupture. A large number of researchers have identified non-coding RNAs as crucial regulators of aortic aneurysm development, both in humans and in animal models. While most work to-date has focused on microRNAs, intriguing information has also begun to emerge regarding the role of long-non-coding RNAs. This review summarizes the currently available data regarding the involvement of non-coding RNAs in aneurysmal aortopathies. Going forward, these represent key potential therapeutic targets that might be leveraged in the future to slow or prevent aortic aneurysm formation, progression and rupture.

Echocardiographic manifestations and chemical composition of stenotic bicuspid aortic valves

Bicuspid aortic valve (BAV) is an inherited form of heart disease with only two aortic valve leaflets via a disorder of cardiac valvulogenesis. We investigated the in vivo echocardiographic features of cardiac morphology in patients with BAV and the ex vivo compositional components of all the excised BAV leaflets isolated from BAV patients. Three BAV patients were randomly selected. All patients underwent 2D transthoracic echocardiography (TTE) with a Doppler ultrasound tool. The compositional components of each respective BAV leaflet for all the excised BAVs were determined by a portable fiber-optic Raman spectroscopy. Preoperative TTE revealed the thickened and calcified BAV leaflets, and stenotic aortic flow for all BAV patients. These BAV patients exhibited severe aortic stenosis (AS) by the lower values of aortic valve area (AVA) index. One patient showed a more significant left ventricle hypertrophy, whereas two patients exhibited a significant aortic regurgitation (AR). In addition, three different Raman spectral patterns were summed up from 121 randomized Raman determinations for all the excised BAV leaflets. The main calcified deposition in each BAV leaflet was formed by large amounts of calcium hydroxyapatite and type-B carbonate apatite (Raman bands at 960 and 1070 cm^-1). The calcified BAV leaflets were composed of different compositional components such as calcium hydroxyapatite, type-B carbonate apatite, lipids, proteins, cholesterol and β-carotene. The rare NL subtype of type 1 BAV morphotype was found in one patient, but two patients had the purely BAV morphotype with two equal-sized leaflets.

Enlightening the Association between Bicuspid Aortic Valve and Aortopathy

Bicuspid aortic valve (BAV) patients have an increased incidence of developing aortic dilation. Despite its importance, the pathogenesis of aortopathy in BAV is still largely undetermined. Nowadays, intense focus falls both on BAV morphology and progression of valvular dysfunction and on the development of aortic dilation. However, less is known about the relationship between aortic valve morphology and aortic dilation. A better understanding of the molecular pathways involved in the homeostasis of the aortic wall, including the extracellular matrix, the plasticity of the vascular smooth cells, TGFβ signaling, and epigenetic dysregulation, is key to enlighten the mechanisms underpinning BAV-aortopathy development and progression. To date, there are two main theories on this subject, i.e., the genetic and the hemodynamic theory, with an ongoing debate over the pathogenesis of BAV-aortopathy. Furthermore, the lack of early detection biomarkers leads to challenges in the management of patients affected by BAV-aortopathy. Here, we critically review the current knowledge on the driving mechanisms of BAV-aortopathy together with the current clinical management and lack of available biomarkers allowing for early detection and better treatment optimization.

A Typical Immune T/B Subset Profile Characterizes Bicuspid Aortic Valve: In an Old Status?

Bicuspid valve disease is associated with the development of thoracic aortic aneurysm. The molecular mechanisms underlying this association still need to be clarified. Here, we evaluated the circulating levels of T and B lymphocyte subsets associated with the development of vascular diseases in patients with bicuspid aortic valve or tricuspid aortic valve with and without thoracic aortic aneurysm. We unveiled that the circulating levels of the MAIT, CD4+IL−17A+, and NKT T cell subsets were significantly reduced in bicuspid valve disease cases, when compared to tricuspid aortic valve cases in either the presence or the absence of thoracic aortic aneurysm. Among patients with tricuspid aortic valve, these cells were higher in those also affected by thoracic aortic aneurysm. Similar data were obtained by examining CD19+ B cells, naïve B cells (IgD+CD27−), memory unswitched B cells (IgD+CD27+), memory switched B cells (IgD−CD27+), and double-negative B cells (DN) (IgD−CD27−). These cells resulted to be lower in subjects with bicuspid valve disease with respect to patients with tricuspid aortic valve. In whole, our data indicate that patients with bicuspid valve disease show a quantitative reduction of T and B lymphocyte cell subsets. Future studies are encouraged to understand the molecular mechanisms underlying this observation and its pathophysiological significance.

Protein-altering and regulatory genetic variants near GATA4 implicated in bicuspid aortic valve

Bicuspid aortic valve (BAV) is a heritable congenital heart defect and an important risk factor for valvulopathy and aortopathy. Here we report a genome-wide association scan of 466 BAV cases and 4,660 age, sex and ethnicity-matched controls with replication in up to 1,326 cases and 8,103 controls. We identify association with a noncoding variant 151 kb from the gene encoding the cardiac-specific transcription factor, GATA4, and near-significance for p.Ser377Gly in GATA4. GATA4 was interrupted by CRISPR-Cas9 in induced pluripotent stem cells from healthy donors. The disruption of GATA4 significantly impaired the transition from endothelial cells into mesenchymal cells, a critical step in heart valve development.