Purpose: Finite element analysis (FEA) has been used to predict wall stress in ascending thoracic aortic aneurysm (ATAA) in order to evaluate risk of dissection or rupture. Patient-specific FEA requires detailed information on ATAA geometry, loading conditions, material properties, and wall thickness. Unfortunately, measuring aortic wall thickness and mechanical properties non-invasively poses a significant challenge, necessitating the use of non-patient-specific data in most FE simulations.
View Article and Find Full Text PDFObjective: This retrospective study aimed to compare the outcomes of sutureless aortic valve replacement (su-AVR) and conventional bioprosthetic sutured AVR (cAVR) in high-risk patients undergoing redo surgery.
Methods: A total of 79 patients who underwent redo AVR between 2014 and 2021 were included in the study. Of these, 27 patients underwent su-AVR and 52 underwent cAVR.
Thoracic aortic aneurysm and dissection (TAAD) are complex disease states with high morbidity and mortality that pose significant challenges to early diagnosis. Patients with an aneurysm are asymptomatic and typically present to the emergency department only after the development of a dissection. The extracellular matrix (ECM) plays a crucial role in regulating the aortic structure and function.
View Article and Find Full Text PDFObjectives: The aim of this study was to develop a method to quantify the peel force in an in vitro model simulating repair of ascending aortic dissections with tissue glue (Bioglue).
Methods: This study adapted an adhesive T-Peel test for the determination of the peel strength of adhesives by measuring the peeling force of a T-shaped bonded tissue. Measurements were performed on iatrogenic dissected ascending porcine aorta, which has been repaired with Bioglue using different pressure levels.
Background: Simulation is playing an increasingly important role in surgical training but is not yet a mandatory part of most surgical curricula. A simulator must undergo rigorous validation to verify it as a reliable tool. The aim of this study was to review the literature to identify simulators that are currently available to augment thoracic surgical training and to analyze any evidence supporting or validating them.
View Article and Find Full Text PDFThe wide uptake of anterior right thoracotomy (ART) as an approach for aortic valve replacement (AVR) has been limited despite initial reports of its use in 1993. Compared with median sternotomy, and even ministernotomy, ART is considered to be less traumatic to the chest wall and to help facilitate quicker patient recovery. In this statement, a consensus agreement is outlined that describes the potential benefits of the ART AVR.
View Article and Find Full Text PDFComput Methods Programs Biomed
May 2023
Background And Objective: Numerical simulations of blood flow are a valuable tool to investigate the pathophysiology of ascending thoratic aortic aneurysms (ATAA). To accurately reproduce in vivo hemodynamics, computational fluid dynamics (CFD) models must employ realistic inflow boundary conditions (BCs). However, the limited availability of in vivo velocity measurements, still makes researchers resort to idealized BCs.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFBackground: The decision to conserve or replace the native aortic valve following acute type-A aortic dissection (ATAAD) is an area of cardiac surgery without standardized practice. This single-center retrospective study analysed the long-term performance of the native aortic valve and root following surgery for ATAAD.
Methods: Between 2009 and 2018 all cases ATAAD treated at Royal Brompton and Harefield NHS Foundation Trust were analysed.
Objectives: This study aims to characterize the material properties of ascending thoracic aortic aneurysmal tissue, using regional biomechanical assessment of both tensile and dissection propagation peel strength.
Methods: Thirty-four aneurysm specimens (proximal thoracic aorta) were harvested en-bloc from patients undergoing surgery for aneurysm replacement. Specimens were processed into regional samples of similar shapes covering the whole aneurysm isosurface, according to a structured protocol, in both orientations (longitudinal and circumferential).
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.
Background: Sutureless prostheses may have added benefit when combined with minimal access surgery, although this has not been fully assessed in the literature. This study aims to provide a comparative analysis of the Perceval valve comparing median sternotomy (MS) with mini-sternotomy (MIS).
Methods: A retrospective analysis of prospectively collected data was conducted for all isolated aortic valve replacement (AVR), using the Perceval valve, for severe aortic stenosis cases in the period 2014 to 2019.
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. Ten patients undergoing surgery for ATAA were recruited.
View Article and Find Full Text PDFA serious complication of transcatheter valves is the mechanistic failure of the deployment system and prosthesis migration. We report the case of a transcatheter aortic valve implantation which failed during implantation resulting in dislodgement of the prosthesis. Emergency surgery to retrieve the deployment system and surgically replace the native valve was the only option to salvage the patient.
View Article and Find Full Text PDFObjectives: The aim of this study was to systematically review the simulators that are currently available for coronary artery bypass graft and valve surgery and, in addition, to review the validation evidence supporting them and to recommend several simulators for training based on the analysis of results.
Methods: A systematic literature search of the MEDLINE® (1946 to May 2021) and EMBASE® (1947 to May 2021) databases was performed to identify simulators for coronary artery and valvular procedures in cardiothoracic surgery. A selection of keywords and MeSH terms was used to execute the literature search.
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.
View Article and Find Full Text PDFStrain 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.
View Article and Find Full Text PDFBackground: The subclavian artery is an alternative access route for transcatheter aortic valve implantation (TAVI), with a potential advantage in patients unsuitable for traditional access routes such as the femoral artery. This study aimed to determine the safety and efficacy of the -subclavian (TSc) compared to the -femoral (TF) approach.
Methods: A systematic review was conducted on two online databases: Embase and Medline.
Disseminating the practice of minimally invasive mitral surgery (mini-MVS) can be challenging, despite its original case reports a few decades ago. The penetration of this technology into clinical practice has been limited to centres of excellence, and mitral surgery in most general cardiothoracic centres remains to be conducted via sternotomy access as a first line. The process for the uptake of mini-MVS requires clearer guidance and standardisation for the processes involved in its implementation.
View Article and Find Full Text PDFBackground: While minimally invasive techniques for aortic valve replacement (AVR) have been shown to be safe, limited data exist comparing the varying approaches. This study aimed to compare the outcomes between two minimally invasive approaches for AVR: mini-sternotomy (MS) and right anterior thoracotomy (RAT).
Materials And Methods: A systematic search of MEDLINE, EMBASE, and OVID was conducted for the period 1990-2019.
Background: Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.
Methods: PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD.
Background: The safety of training in off-pump coronary artery bypass (OPCAB) surgery and the stage at which trainees should be exposed to this technique remain controversial. This single-center retrospective study aimed to compare outcomes of OPCAB surgery in consultant and trainee cases.
Methods: Between 2014 and 2018, all isolated OPCAB operations performed under the care of a consultant surgeon (G.