Bicuspid Aortic Valve Disease: Classifications, Treatments, and Emerging Transcatheter Paradigms.

Bicuspid aortic valve (BAV) is a common congenital valvular malformation, which may lead to early aortic valve disease and bicuspid-associated aortopathy. A novel BAV classification system was recently proposed to coincide with transcatheter aortic valve replacement being increasingly considered in younger patients with symptomatic BAV, with good clinical results, yet without randomized trial evidence. Procedural technique, along with clinical outcomes, have considerably improved in BAV patients compared with tricuspid aortic stenosis patients undergoing transcatheter aortic valve replacement. The present review summarizes the novel BAV classification systems and examines contemporary surgical and transcatheter approaches.

Mid-term outcomes of aortic valve repair using an anatomically shaped internal annuloplasty ring.

OBJECTIVES: The Hemispherical Aortic Annuloplasty Reconstructive Technology (HAART) ring is a rigid, internal and geometric device. The objective of this article is to assess the mid-term outcomes of aortic valve repair (AVr) using this prosthesis. METHODS: A prospectively maintained database was used to obtain outcomes for adult patients undergoing AVr using the HAART ring between September 2017 and June 2023. All aortic patients at our institution undergo life-long surveillance with regular assessment and valve imaging. RESULTS: Seventy-one patients underwent AVr using the HAART device: 53 had a trileaflet valve and 18 a bicuspid valve. The median age was 54 years, and most were male (79%). Many required concomitant intervention: 46% had a root procedure and 77% an arch repair. There were no in-hospital deaths, and the median postoperative stay was 5 days. At a mean follow-up of 3.9 (±1.1) years, freedom from reoperation was 94%. Late imaging demonstrated: zero trace (25%), 1+ (54%), 2+ (15%) and 4+ (6%) aortic insufficiency (AI). Eleven patients have ≥moderate AI under surveillance, all of whom have a trileaflet valve (21% of trileaflet patients). Four patients required reoperation: 3 for ring dehiscence and 1 for endocarditis. CONCLUSIONS: Although early results using the HAART device are encouraging, mid-term results raise concern as 21% of trileaflet patients developed recurrent ≥moderate AI by 4 years post-repair. We experienced 3 incidences of ring dehiscence requiring reoperation. Based on this, we recommend caution using the sub-annular approach for stabilization in patients with trileaflet aortic valves. Long-term results are needed to assess outcomes against established techniques.

The genetic basis of thoracic aortic disease: The future of aneurysm classification?

The expansion in the repertoire of genes linked to thoracic aortic aneurysms (TAA) has revolutionised our understanding of the disease process. The clinical benefits of such progress are numerous, particularly helping our understanding of non-syndromic hereditary causes of TAA (HTAAD) and further refinement in the subclassification of disease. Furthermore, the understanding of aortic biomechanics and mechanical homeostasis has been significantly informed by the discovery of deleterious mutations and their effect on aortic phenotype. The drawbacks in genetic testing in TAA lie with the inability to translate genotype to accurate prognostication in the risk of thoracic aortic dissection (TAD), which is a life-threatening condition. Under current guidelines, there are no metrics by which those at risk for dissection with normal aortic diameters may undergo preventive surgery. Future research lies with more advanced genetic diagnosis of HTAAD and investigation of the diverse pathways involved in its pathophysiology, which will i) serve to improve our understanding of the underlying mechanisms, ii) improve guidelines for treatment and iii) prevent complications for HTAAD and sporadic aortopathies.

Geometry and flow in ascending aortic aneurysms are influenced by left ventricular outflow tract orientation: Detecting increased wall shear stress on the outer curve of proximal aortic aneurysms.

BACKGROUND: The geometrical characterization of ascending thoracic aortic aneurysms in clinical practice is limited to diameter measurements. Despite growing interest in hemodynamic assessment, its relationship with ascending thoracic aortic aneurysm pathogenesis is poorly understood. This study examines the relationship between geometry of the ventriculo-aortic junction and blood flow patterns in ascending thoracic aortic aneurysm disease. METHODS: Thirty-three patients with ascending thoracic aortic aneurysms (exclusions: bicuspid aortic valves, connective tissue disease) underwent 4-dimensional flow magnetic resonance imaging. After image segmentation, geometrical parameters were measured, including aortic curvature, tortuosity, length, and diameter. A unique angular measurement made by the trajectory of the left ventricular outflow tract axis and the proximal aorta was also conducted. Velocity profiles were quantitatively and qualitatively analyzed. In addition, 11 patients (33%) underwent wall shear stress mapping of the ascending thoracic aortic aneurysm region using computational fluid dynamics simulation. RESULTS: Greater left ventricular outflow tract aortic angles were associated with larger aortic diameters at the levels of the sinus (coefficient = 0.387, P = .014) and ascending aorta (coefficient = 0.284, P = .031). Patients with left ventricular outflow tract aortic angles greater than 60° had marked asymmetric flow acceleration on the outer curvature in the proximal aorta, ascertained from 4-dimensional flow analysis. For patients undergoing computational fluid dynamics assessment, regression analysis found that higher left ventricular outflow tract aortic angles were associated with significantly higher wall shear stress values in the outer curve of the aorta (coefficient 0.07, 95% confidence interval 0.04-0.11, P = .002): Angles greater than 50° yielded time-averaged wall shear stress values greater than 2.5 Pa, exhibiting a linear relationship. CONCLUSIONS: Our findings strengthen the hypothesis of flow-mediated ascending thoracic aortic aneurysm disease progression and that left ventricular outflow tract aortic angle may be a predictor of disease severity.

Basic principles of cardiothoracic surgery training: a position paper by the European Association for Cardiothoracic Surgery Residents Committee.

OBJECTIVES: Across Europe there are significant variations in the fundamental structure and content of cardiothoracic surgery (CTS) training programmes. Previous efforts have been made to introduce a Unified European Training System, which outlined the fundamentals of the ideal programme and supported a paradigm shift from an apprenticeship to a competency-based model. This article's goal was to define key structural, administrative and executive details of such a programme to lay the foundations for the standardization of cardiothoracic surgical training across Europe. METHODS: The European Association for Cardiothoracic Surgery Residents Committee had previously conducted a residents' training survey across Europe in 2020. Training curricula from the twelve most represented countries across Europe were either searched online or obtained from the countries' national trainee representative and reviewed by the committee. Information was collated and placed into one of the following categories to develop the position paper: (i) selection of eligible candidates, (ii) guidance for an outcome-based syllabus, (iii) documentation and evaluation of training progress, (iv) mandatory rotations and training courses, (v) number of independent or assisted cases and (vi) requirements and quality assurance of teachers. RESULTS: An independent professional body should promote an outcome-based syllabus and take responsibility for the training programme's quality assurance. Trainees should be selected on merit by an open and transparent process. Training should be delivered within a defined period and supervised by an appointed training committee to ensure its implementation. This committee should review the trainees progression regularly, provide feedback and offer trainees the opportunity to experience various training environments and trainers. A common electronic portal be used by trainees to record their agreed objectives and to evidence their completion. Trainees should regularly attend specialty-relevant courses and conferences to promote professional and academic development. The end of training is reached when the formal requirements of the training programme are met and the trainee is able to perform at the level expected of a day-1 independent surgeon. CONCLUSIONS: This article defines the key structural, administrative, and executive principles for CTS training. Programmes are encouraged to review and modify their training curricula, if necessary, to ensure the delivery of high-quality, standardized, outcome-orientated CTS training across Europe.

Determining the genetic contribution in patients with non-syndromic ascending thoracic aortic aneurysms: Correlation with findings from computational pathology.

OBJECTIVES: This study aims to identify the clinical utility of targeted-genetic sequencing in a cohort of patients with TAA and establish a new method for regional histological characterisation of TAA disease. METHODS: Fifty-four patients undergoing surgery for proximal TAA were recruited. EXCLUSIONS: connective tissue disease, bicuspid aortic valves, redo surgery. All patients underwent next generation sequencing (NGS) using a custom gene panel containing 63 genes previously associated with TAA on Illumina MiSeqor NextSeq550 platforms. Explanted TAA tissue was obtained en-bloc from 34/54 patients, and complete circumferential strips of TAA tissue processed into whole slides which were subsequently digitalised. Computational pathology methods were employed to quantify elastin, cellularity and collagen in six equally divided regions across the whole aneurysm circumference. RESULTS: Of 54 patients, clearly pathogenic or potentially pathogenic variants were found in 7.4%: namely LOX, PRKG1, TGFBR1 and SMAD3 genes. 55% had at least one variant of unknown significance (VUS) and seven of the VUSs were in genes with a strong disease association (category A) genes, whilst 15 were from moderate risk (category B) genes. Elastin and collagen abundance displayed high regional variation throughout the aneurysm circumference. In patients with <60% total elastin, the loss of elastin was more significant on the outer curve (38.0% vs 47.4%, p = 0.0094). The presence of VUS, higher pulse wave velocity and advancing age were predictors of elastin loss (regression analysis: p < 0.05). CONCLUSIONS: These findings demonstrate the heterogeneity of TAA disease microstructure and the potential link between histological appearance and clinical factors, including genetic variation.

High Wall Shear Stress can Predict Wall Degradation in Ascending Aortic Aneurysms: An Integrated Biomechanics Study.

Background: Blood flow patterns can alter material properties of ascending thoracic aortic aneurysms (ATAA) via vascular wall remodeling. This study examines the relationship between wall shear stress (WSS) obtained from image-based computational modelling with tissue-derived mechanical and microstructural properties of the ATAA wall using segmental analysis. Methods: Ten patients undergoing surgery for ATAA were recruited. Exclusions: bicuspid aortopathy, connective tissue disease. All patients had pre-operative 4-dimensional flow magnetic resonance imaging (4D-MRI), allowing for patient-specific computational fluid dynamics (CFD) analysis and anatomically precise WSS mapping of ATAA regions (6-12 segments per patient). ATAA samples were obtained from surgery and subjected to region-specific tensile and peel testing (matched to WSS segments). Computational pathology was used to characterize elastin/collagen abundance and smooth muscle cell (SMC) count. Results: Elevated values of WSS were predictive of: reduced wall thickness [coef -0.0489, 95% CI (-0.0905, -0.00727), p = 0.022] and dissection energy function (longitudinal) [-15,0, 95% CI (-33.00, -2.98), p = 0.048]. High WSS values also predicted higher ultimate tensile strength [coef 0.136, 95% CI (0 0.001, 0.270), p = 0.048]. Additionally, elevated WSS also predicted a reduction in elastin levels [coef -0.276, 95% (CI -0.531, -0.020), p = 0.035] and lower SMC count ([oef -6.19, 95% CI (-11.41, -0.98), p = 0.021]. WSS was found to have no effect on collagen abundance or circumferential mechanical properties. Conclusions: Our study suggests an association between elevated WSS values and aortic wall degradation in ATAA disease. Further studies might help identify threshold values to predict acute aortic events.

Subtle aortic dissection in a patient with severe aortic regurgitation and undiagnosed bicuspid aortic valve: A case report with a literature review.

BACKGROUND AND AIM OF THE STUDY: A subtle aortic dissection can be challenging to detect despite the availability of multiple diagnostic modalities. Whilst rare, the inability to detect this variant of aortic dissection can lead to a dismal prognosis. We present an extremely rare case of a subtle aortic dissection with supra-annular aortic root intimal tear and acute severe aortic regurgitation in a patient with a bicuspid aortic valve. METHODS: Case report and literature review conserning subtle aortic dissection is provided. RESULTS: Initial concerns were either aortic dissection or infective endocarditis. Despite advanced multimodality preoperative imaging, diagnosis was made intraoperatively and a Bentall procedure with a mechanical aortic valve was performed. CONCLUSIONS: Our case along with the review of current literature emphasizes that current imaging techniques may be inadequate for diagnosis of this rare variant of aortic dissection.

Validation of markerless strain-field optical tracking approach for soft tissue mechanical assessment.

Strain measurement during tissue deformation is crucial to elucidate relationships between mechanical loading and functional changes in biological tissues. When combined with specified loading conditions, assessment of strain fields can be used to craft models that accurately represent the mechanical behavior of soft tissue. Inhomogeneities in strain fields may be indicative of normal or pathological inhomogeneities in mechanical properties. In this study, we present the validation of a modified Demons registration algorithm for non-contact, marker-less strain measurement of tissue undergoing uniaxial loading. We validate the algorithm on a synthetic dataset composed of artificial deformation fields applied to a speckle image, as well as images of aortic sections of varying perceptual quality. Initial results indicate that Demons outperforms recent Optical Flow and Digital Image Correlation methods in terms of accuracy and robustness to low image quality, with similar runtimes. Demons achieves at least 8% lower maximal deviation from ground truth on 50% biaxial and shear strain applied to aortic images. To illustrate utility, we quantified strain fields of multiple human aortic specimens undergoing uniaxial tensile testing, noting the formation of strain concentrations in areas of rupture. The modified Demons algorithm captured a large range of strains (up to 50%) and provided spatially resolved strain fields that could be useful in the assessment of soft tissue pathologies.

Challenges and satisfaction in Cardiothoracic Surgery Residency Programmes: insights from a Europe-wide survey.

OBJECTIVES: The increasing complexity of surgical patients and working time constraints represent challenges for training. In this study, the European Association for Cardio-Thoracic Surgery Residents' Committee aimed to evaluate satisfaction with current training programmes across Europe. METHODS: We conducted an online survey between October 2018 and April 2019, completed by a total of 219 participants from 24 countries. RESULTS: The average respondent was in the fourth or fifth year of training, mostly on a cardiac surgery pathway. Most trainees follow a 5-6-year programme, with a compulsory final certification exam, but no regular skills evaluation. Only a minority are expected to take the examination by the European Board of Cardiothoracic Surgery. Participants work on average 61.0 ± 13.1 h per week, including 27.1 ± 20.2 on-call. In total, only 19.7% confirmed the implementation of the European Working Time Directive, with 42.0% being unaware that European regulations existed. Having designated time for research was reported by 13.0%, despite 47.0% having a postgraduate degree. On average, respondents rated their satisfaction 7.9 out of 10, although 56.2% of participants were not satisfied with their training opportunities. We found an association between trainee satisfaction and regular skills evaluation, first operator experience and protected research time. CONCLUSIONS: On average, residents are satisfied with their training, despite significant disparities in the quality and structure of cardiothoracic surgery training across Europe. Areas for potential improvement include increasing structured feedback, research time integration and better working hours compliance. The development of European guidelines on training standards may support this.

The risk of misdiagnosis in acute thoracic aortic dissection: a review of current guidelines.

Acute aortic syndrome and in particular aortic dissection (AAD) persists as a cause of significant morbidity and mortality despite improvements in surgical management. This clinical review aims to explore the risks of misdiagnosis, outcomes associated with misdiagnosis and evaluate current diagnostic methods for reducing its incidence.Due to the nature of the pathology, misdiagnosing the condition and delaying management can dramatically worsen patient outcomes. Several diagnostic challenges exist, including low prevalence, rapidly propagating pathology, non-discrete symptomatology, non-specific signs, analogy with other acute conditions and lack of management infrastructure. A similarity to acute coronary syndromes is a specific concern and risks patient maltreatment. AAD with malperfusion syndromes are both a cause of misdiagnosis and marker of disease complication, requiring specifically tailored management plans from the emergency setting.Despite improvements in diagnostic measures, including imaging modalities and biomarkers, misdiagnosis of AAD remains commonplace and current guidelines are relatively limited in preventing its occurrence. This paper recommends the early use of AAD risk scoring, focused echocardiography and most importantly, fast-tracking patients to cross-sectional imaging where the suspicion of AAD is high. This has the potential to improve the diagnostic process for AAD and limit the risk of misdiagnosis. However, our understanding remains limited by the lack of large patient datasets and an adequately audited processes of emergency department practice.

Phase-contrast magnetic resonance imaging and computational fluid dynamics assessment of thoracic aorta blood flow: a literature review.

The death rate from thoracic aortic disease is on the rise and represents a growing global health concern as patients are often asymptomatic before acute events, which have devastating effects on health-related quality of life. Biomechanical factors have been found to play a major role in the development of both acquired and congenital aortic diseases. However, much is still unknown and translational benefits of this knowledge are yet to be seen. Phase-contrast cardiovascular magnetic resonance imaging of thoracic aortic blood flow has emerged as an exceptionally powerful non-invasive tool enabling visualization of complex flow patterns, and calculation of variables such as wall shear stress. This has led to multiple new findings in the areas of phenotype-dependent bicuspid valve flow patterns, thoracic aortic aneurysm formation and aortic prosthesis performance assessment. Phase-contrast cardiovascular magnetic resonance imaging has also been used in conjunction with computational fluid modelling techniques to produce even more sophisticated analyses, by allowing the calculation of haemodynamic variables with exceptional temporal and spatial resolution. Translationally, these technologies may potentially play a major role in the emergence of precision medicine and patient-specific treatments in patients with aortic disease. This clinically focused review will provide a systematic overview of key insights from published studies to date.

Diagnosis and management of acute Type-A aortic dissection in emergency departments: Results of a UK national survey.

BACKGROUND: Type A-aortic dissection (TAAD) is a life-threatening diagnosis made in the emergency department (ED). Many presentations mimic acute coronary syndrome (ACS) and over a third of TAAD patients present with raised cardiac enzymes, many of whom have ACS-like changes on the electrocardiogram. The aim of this study was to assess the current practice in diagnosis and management of TAAD. METHODS: Between April and October 2018, a structured survey was distributed to ED Consultants across the UK. Questions surrounded: i) simulated clinical scenarios which mimicked ACS in the early stages (where TAAD could simultaneously be the diagnosis); and ii) ED infrastructure for TAAD management. RESULTS: Responses were received from 175 ED consultants across 70 hospital Trusts. In the context of chest pain and ST elevation, 97% of ED consultants considered this sufficient to diagnose ACS, and over half (54%) agreed with committing to treatment (including the use of thrombolysis) prior to further investigation. Early committers to ACS treatment were statistically less likely to ever order a CT scan or d-dimer (OR 0.31, 95% CI 0.12-0.83, p = 0.02). In total, 32% of consultants reported they would ever request a CT chest in the context of chest pain and elevated troponin. The lack of an AD algorithm was the strongest predictor of clinicians avoiding the use of more definitive investigations for TAAD (OR 0.31, 95% CI 0.01-0.64, p = 0.05). CONCLUSIONS: In TAAD patients presenting with chest pain and elevated cardiac enzymes there is a high probability of ACS treatment being commenced and a significant risk of failing to request the necessary imaging to diagnose TAAD.

Can activity monitors predict outcomes in patients with heart failure? A systematic review.

Actigraphy is increasingly incorporated into clinical practice to monitor intervention effectiveness and patient health in congestive heart failure (CHF). We explored the prognostic impact of actigraphy-quantified physical activity (AQPA) on CHF outcomes. PubMed and Medline databases were systematically searched for cross-sectional studies, cohort studies or randomised controlled trials from January 2007 to December 2017. We included studies that used validated actigraphs to predict outcomes in adult HF patients. Study selection and data extraction were performed by two independent reviewers. A total of 17 studies (15 cohort, 1 cross-sectional, 1 randomised controlled trial) were included, reporting on 2,759 CHF patients (22-89 years, 27.7% female). Overall, AQPA showed a strong inverse relationship with mortality and predictive utility when combined with established risk scores, and prognostic roles in morbidity, predicting cognitive function, New York Heart Association functional class and intercurrent events (e.g. hospitalisation), but weak relationships with health-related quality of life scores. Studies lacked consensus regarding device choice, time points and thresholds of PA measurement, which rendered quantitative comparisons between studies difficult. AQPA has a strong prognostic role in CHF. Multiple sampling time points would allow calculation of AQPA changes for incorporation into risk models. Consensus is needed regarding device choice and AQPA thresholds, while data management strategies are required to fully utilise generated data. Big data and machine learning strategies will potentially yield better predictive value of AQPA in CHF patients.

Single stage repair for aortic root aneurysm in a patient with coexisting coarctation incorporating the Cabrol technique: a case report.

BACKGROUND: A 44 year old man who presented with a history of chest pain and dyspnoea was found to have an aneurysm of the aortic root, aortic valve insufficiency, and coarctation of the aorta. CASE PRESENTATION: The patient underwent a single stage procedure to treat the aortic root, valve and coarctation with a composite valved conduit and extra-anatomic bypass of the coarctation. The modified Cabrol technique was necessary to attach the coronary buttons due to grossly abnormal anatomy. The patient made a remarkable recovery and was discharged on the 8th post-operative day. CONCLUSION: This case report highlights the feasibility and efficacy of performing a single stage procedure on complex coarctation with associated cardiac defects. To the best of our knowledge, this is the first report of the modified Cabrol technique being used in this particular setting.

Vivien Theodore Thomas (1910-1985): An African-American laboratory technician who went on to become an innovator in cardiac surgery.

Vivien Theodore Thomas (1910-1985) was an African-American laboratory technician and instructor of surgery at Johns Hopkins University, Baltimore. He was born as the grandson of a slave in Lousiana, working as a carpenter and subsequently as a laboratory technician after the great depression and the loss of his savings derailed his plans to become a doctor. In his role as a laboratory technician, he overcame challenging personal circumstances to become an innovator in paediatric cardiac surgery, despite having no formal college education. He played an important role in assisting Alfred Blalock and Helen Taussig in the development of the 'Blalock-Taussig' shunt, a procedure used to improve the survival of children with cyanotic congenital heart defects. He also contributed to major breakthroughs in research covering a spectrum of disorders such as traumatic shock, coarctation of the aorta and transposition of the great arteries. He acted as a teacher and mentor to a generation of surgical residents and technicians who went on to become leaders in their field across the USA. A television film based on his life was premiered by HBO in 2004 titled 'Something the Lord made'.