Front Lines of Thoracic Surgery

Front Lines of Thoracic Surgery collects up-to-date contributions on some of the most debated topics in today's clinical practice of cardiac, aortic, and general thoracic surgery,and anesthesia as viewed by authors personally involved in their evolution. The strong and genuine enthusiasm of the authors was clearly perceptible in all their contributions and I'm sure that will further stimulate the reader to understand their messages. Moreover, the strict adhesion of the authors' original observations and findings to the evidence base proves that facts are the best guarantee of scientific value. This is not a standard textbook where the whole discipline is organically presented, but authors' contributions are simply listed in their pertaining subclasses of Thoracic Surgery. I'm sure that this original and very promising editorial format which has and free availability at its core further increases this book's value and it will be of interest to healthcare professionals and scientists dedicated to this field

From Benchtop to Beside: Patient-specific Outcomes Explained by Invitro Experiment

Study: Recent analyses show that females have higher early postoperative (PO) mortality and right ventricular failure (RVF) than males after left ventricular assist device (LVAD) implantation; and that this association is partially mediated by smaller LV size in females. Benchtop experiments allow us to investigate patient-specific (PS) characteristics in a reproducible way given the fact that the PS anatomy and physiology is mimicked accurately. With multiple heart models of varying LV size, we can directly study the individual effects of titrating the LVAD speed and the resulting bi-ventricular volumes, shedding light on the interplay between LV and RV as well as resulting inter-ventricular septum (IVS) positions, which may cause the different outcomes pertaining to sex. Methods: In vitro, we studied the impact of the heart size to IVS position using two smaller and two larger sized PS silicone heart phantoms derived from clinical CT images (Fig. 1A). With ultrasound crystals that were integrated on a placeholder inflow cannula, the IVS position was measured during LV and RV volume changes (dV) mimicking varying ventricular loading states (Fig. 1B). Figure 1 A Two small (blue) and two large PS heart phantoms (orange) on B benchtop. C Median septum curvature results. LVEDD/LVV/RVV: LV enddiastolic diameter/LV and RV volume. Results: Going from small to large dV, at zero curvature, the septum starts to shift towards the left; for smaller hearts at dV = -40 mL and for larger hearts at dV = -50 mL (Fig. 1C). This result indicates that smaller hearts are more prone to an IVS shift to the left than larger hearts. We conclude that smaller LV size may therefore mediate increased early PO LVAD mortality and RVF observed in females compared to males. Novel 3D silicone printing technology enables us to study accurate, PS heart models across a heterogeneous patient population. PS relationships can be studied simultaneously to clinical assessments and support the decision-making prior to LVAD implantation

A Journey Through The Thoracic Aorta: From Root To Arch

This thesis investigated the clinical and pathological outcomes of disease of the aortic valve and the ascending aorta, including the aortic root. Purpose: The aortic valve and proximal aorta are the anatomical origin of the systemic circulation and pathology in this area can be catastrophic. Despite this, there is limited knowledge of the pathophysiology of proximal aortic aneurysms and patient outcomes for treatment strategies of aortic valve disease. The purpose of this thesis is to strengthen the knowledge of pathology affecting the thoracic aorta so that it can help guide clinical management in the future. Aims: This thesis aims to investigate the effects of pathology on the aortic valve and thoracic ascending aorta through determination of: 1. The pathophysiology of proximal aortic aneurysms, specifically focusing on evaluating aortic root and ascending aortic aneurysm in relation to (a) histology (Chapter 2) and (b) propensity to aortic rupture in pigs in-vitro (Chapter 3) and in-vivo (Chapter 4) models; and 2. Comparing SAVR & TAVR in relation to (a) clinical outcomes (Chapter 5) and (b) patient-related outcomes (Chapter 6). Methods: Chapter 2, focused on histological analysis of aneurysmal aortas, and involved laboratory preparation of human aneurysmal and non-aneurysmal tissue and analysis utilizing histological and immunohistochemistry techniques. Chapter 3, which focused on a laboratory pig model in ascending aorta and aortic root rupture, involved laboratory preparation of pig non-aneurysmal samples, and utilised a unique pressure testing apparatus, to determine the maximal stress the root and ascending aorta can withstand prior to rupture. This was a pilot study for Chapter 4. Chapter 4, which focused on a live pig model in ascending aorta and aortic root rupture, involved placement of live pigs on cardiopulmonary bypass, and determination of maximal aortic pressures prior to rupture or failure of the aorta clinically and radiologically using 4D flow MRI. This ruptured tissue was then analysed utilising histological and immunohistochemistry techniques. Chapter 5 which focused on clinical outcomes of aortic valve surgery, utilised the ANZSCTS national database from Monash Health, incorporating data collection and analysis from 2001 to 2019. Chapter 6 which focused on the patient-related outcomes following aortic valve surgery, involved the use of validated questionnaires of patients over a 12-month period following their surgery. Specific outcomes measured included frailty, depression, angina, and quality of life. Results and Discussion: Chapter 2, 3, and 4 focus on the comparisons in structure between two anatomical regions of the aorta, while Chapter 5 and 6 focus on comparisons in approach between two methods of aortic valve replacement. All Chapters give us valuable knowledge as to how we can manage aortic pathology not only during surgery, but also during the patient’s perioperative journey. The aortic root is the most susceptible region of the thoracic aorta and is predisposed to progression of pathology and rupture in clinical testing. The aortic root is more vulnerable to high pressures, further exacerbated by aneurysmal changes, supported by both microscopic and macroscopic characteristics, while the ascending aorta retains its resilience in comparison. This identified a difference between the aortic root and ascending aorta not only in known anatomical and physiological form, but in each areas ability to maintain its integrity in severe stress and aneurysmal pathological change. With respect to outcomes post aortic valve replacement, the ANZSCTS database showed no difference in composite endpoints of mortality and stroke between Surgical aortic valve replacement (SAVR) and Transcatheter aortic valve replacement (TAVR), while the degree of morbidity (complete heart block requiring pacemaker and vascular complications) was more prevalent in TAVR groups. In contrast, quality of life, depression, angina, and frailty consecutively measured over 12 months, showed significant improvement in both SAVR and TAVR groups, and an obvious benefit to these measures in all patients requiring intervention for aortic stenosis. When these two groups (SAVR and TAVR) were matched, clinically relevant preoperative variables were identified as being predictive of early mortality. Conclusions: The aortic root differs to the ascending aorta under maximal stress and in response to pathological change. Following further clinical testing and human trials, consideration should be for surgical management of these structures as separate entities. Transcatheter approaches are evolving with improved outcomes in large scale randomised trials supported by our findings of composite primary end points, as well as comparable improvement in quality of life, angina, depression, and frailty with surgical groups. Clinically significant morbidity in the form of vascular and electrophysiological complications remain high, and this should be a focus of ongoing long term clinical trials before an absolute incorporation of this technique for all patients with aortic stenosis. Recommendations: This unique analysis offers a new perspective of root and ascending aorta dilatation with strong clinical implications. These two structures deserve new and different management. National databases reporting on outcomes in aortic valve surgery should consider combining databases regardless of transcatheter or open surgical approach, to allow for a comprehensive and accurate representation of morbidity and mortality outcomes. Longer term analysis of these morbidity results should guide clinical guidelines as to the appropriate use of these techniques in aortic valve disease, and the utilisation of combined surgical and physician teams in performing these procedures.Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 202

Medical Robotics

The first generation of surgical robots are already being installed in a number of operating rooms around the world. Robotics is being introduced to medicine because it allows for unprecedented control and precision of surgical instruments in minimally invasive procedures. So far, robots have been used to position an endoscope, perform gallbladder surgery and correct gastroesophogeal reflux and heartburn. The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery. The use of robotics in surgery will expand over the next decades without any doubt. Minimally Invasive Surgery (MIS) is a revolutionary approach in surgery. In MIS, the operation is performed with instruments and viewing equipment inserted into the body through small incisions created by the surgeon, in contrast to open surgery with large incisions. This minimizes surgical trauma and damage to healthy tissue, resulting in shorter patient recovery time. The aim of this book is to provide an overview of the state-of-art, to present new ideas, original results and practical experiences in this expanding area. Nevertheless, many chapters in the book concern advanced research on this growing area. The book provides critical analysis of clinical trials, assessment of the benefits and risks of the application of these technologies. This book is certainly a small sample of the research activity on Medical Robotics going on around the globe as you read it, but it surely covers a good deal of what has been done in the field recently, and as such it works as a valuable source for researchers interested in the involved subjects, whether they are currently “medical roboticists” or not