Photocatalyzed Functionalization of Alkenoic Acids in 3D-Printed Reactors.

The valorization of alkenoic acids possibly deriving from biomass (fumaric and citraconic acids) was carried out through conversion in important building blocks, such as γ-keto acids and succinic acid derivatives. The functionalization was carried out by addition onto the C=C double bond of radicals generated under photocatalyzed conditions from suitable hydrogen donors (mainly aldehydes) and by adopting a decatungstate salt as the photocatalyst. Syntheses were performed under batch (in a glass vessel) and flow (by using 3D-printed reactors) conditions.

Fast Approximate Quantification of Endovascular Stent Graft Displacement Forces in the Bovine Aortic Arch Variant.

Purpose: Displacement forces (s) identify hostile landing zones for stent graft deployment in thoracic endovascular aortic repair (TEVAR). However, their use in TEVAR planning is hampered by the need for time-expensive computational fluid dynamics (CFD). We propose a novel fast-approximate computation of s merely exploiting aortic arch anatomy, as derived from the computed tomography (CT) and a measure of central aortic pressure.

Performance of high conformability vs. high radial force devices in the virtual treatment of TAVI patients with bicuspid aortic valve.

Objective: Transcatheter Aortic Valve Implantation (TAVI) is a consolidated procedure showing a low operative risk and excellent long-term outcomes in patients with aortic stenosis. Patients presenting a bicuspid aortic valve (BAV) often require valve replacement due to the highly calcific nature of the aortic leaflets. However, BAV patients have usually been contraindicated for TAVI due to their complex valve anatomy.

Patient-specific computational fluid dynamics analysis of transcatheter aortic root replacement with chimney coronary grafts.

Objectives: Transcatheter aortic root repair (TARR) consists of the simultaneous endovascular replacement of the aortic valve, the root and the proximal ascending aorta. The aim of the study is to set-up a computational model of TARR to explore the impact of the endovascular procedure on the coronary circulation supported by chimney grafts.

Methods: Computed tomography of a patient with dilated ascending aorta was segmented to obtain a 3-dimensional representation of the proximal thoracic aorta, including aortic root and supra-aortic branches.

Anomalous aortic origin of coronary artery biomechanical modeling: Toward clinical application.

Objectives: Anomalous aortic origin of the coronary artery can be associated with sudden cardiac death and ischemic events. Anatomic static characteristics mainly dictated surgical indications, although adverse events are usually related to dynamic physical effort. We developed a computational model able to simulate anomalous coronary behavior, and we aimed to assess its clinical applicability and to investigate coronary characteristics at increasing loading stress conditions.

Computational Fluid Dynamics Modeling of Proximal Landing Zones for Thoracic Endovascular Aortic Repair in the Bovine Arch Variant.

Background: To assess the endograft displacement forces (DF), which quantify the forces exerted by the pulsatile blood flow on the vessel wall and transmitted on the terminal fixation site of the endograft after its deployment in proximal landing zones (PLZs) of the bovine aortic arch variant.

Methods: Thirty healthy aortic computed tomographic angiographies of subjects with bovine arch configuration (10 per type of arch, I-III) were selected for the purpose of the study. A 3-dimensional model of the aortic arch lumen was reconstructed.

Impact of Aortic Tortuosity on Displacement Forces in Descending Thoracic Aortic Aneurysms.

Objective: As elastin fibres in the aorta deteriorate with age, the descending thoracic aorta (DTA) becomes longer and more tortuous. In patients with DTA aneurysms, this increased tortuosity may result in a hostile haemodynamic environment for thoracic endovascular aortic repair (TEVAR). The objective of this study was to analyse how increased tortuosity affects haemodynamic displacement forces (DFs) in different segments of the DTA in patients with DTA aneurysms (DTAAs).

Geometric Pattern of Proximal Landing Zones for Thoracic Endovascular Aortic Repair in the Bovine Arch Variant.

Objective: The aim was to investigate whether the "bovine" aortic arch (i.e. arch variant with a common origin of the innominate and left carotid artery (CILCA)) is associated with a consistent geometric configuration of proximal landing zones for thoracic endovascular aortic repair (TEVAR).

Aortic arch variant with a common origin of the innominate and left carotid artery as a determinant of thoracic aortic disease: a systematic review and meta-analysis.

The aim of this study was to investigate whether the 'bovine' arch [i.e. arch variant with a common origin of the innominate and left carotid artery (CILCA)] is associated with an increased risk of thoracic aortic disease (TAD).

Blood Flow after Endovascular Repair in the Aortic Arch: A Computational Analysis.

Background:  The benefits of thoracic endovascular aortic repair (TEVAR) have encouraged stent graft deployment more proximally in the aortic arch. This study quantifies the hemodynamic impact of TEVAR in proximal landing zone 2 on the thoracic aorta and the proximal supra-aortic branches.

Methods:  Patients treated with TEVAR in proximal landing zone 2 having available preoperative and 30-day postoperative computer tomography angiography and phase-contrast magnetic resonance imaging data were retrospectively selected.

The Modified Arch Landing Areas Nomenclature identifies hostile zones for endograft deployment: a confirmatory biomechanical study in patients treated by thoracic endovascular aortic repair†.

Objectives: Our goal was to confirm whether the Modified Arch Landing Areas Nomenclature (MALAN) for thoracic endovascular aortic repair, in which each landing area is described by indicating both the proximal landing zone (PLZ) and the type of arch (e.g. 0/I), identifies unfavourable landing zones for endograft deployment in diseased aortas.

Reversed Auxiliary Flow to Reduce Embolism Risk During TAVI: A Computational Simulation and Experimental Study.

Introduction: Endovascular treatments, such as transcatheter aortic valve implantation (TAVI), carry a risk of embolization due to debris dislodgement during various procedural steps. Although embolic filters are already available and marketed, mechanisms underlying cerebral embolism still need to be elucidated in order to further reduce cerebrovascular events.

Methods: We propose an experimental framework with an in silico duplicate allowing release of particles at the level of the aortic valve and their subsequent capture in the supra-aortic branches, simulating embolization under constant inflow and controlled hemodynamic conditions.

Patient-specific CFD modelling in the thoracic aorta with PC-MRI-based boundary conditions: A least-square three-element Windkessel approach.

The increasing use of computational fluid dynamics for simulating blood flow in clinics demands the identification of appropriate patient-specific boundary conditions for the customization of the mathematical models. These conditions should ideally be retrieved from measurements. However, finite resolution of devices as well as other practical/ethical reasons prevent the construction of complete data sets necessary to make the mathematical problems well posed.

The Modified Arch Landing Areas Nomenclature (MALAN) Improves Prediction of Stent Graft Displacement Forces: Proof of Concept by Computational Fluid Dynamics Modelling.

Objective: To assess whether the Modified Arch Landing Areas Nomenclature (MALAN), which merges Ishimaru's map with the Aortic Arch Classification, predicts the magnitude of displacement forces and their orientation in proximal landing zones for TEVAR.

Methods: Computational fluid dynamic (CFD) modelling was employed to prove the hypothesis. Healthy aorta CT angiography scans were selected based on aortic arch geometry to reflect Types I to III arches equally (each n = 5).