Development of a Surgical Assistance System for Guiding Transcatheter Aortic Valve Implantation

Development of image-guided interventional systems is growing up rapidly in the recent years. These new systems become an essential part of the modern minimally invasive surgical procedures, especially for the cardiac surgery. Transcatheter aortic valve implantation (TAVI) is a recently developed surgical technique to treat severe aortic valve stenosis in elderly and high-risk patients. The placement of stented aortic valve prosthesis is crucial and typically performed under live 2D fluoroscopy guidance. To assist the placement of the prosthesis during the surgical procedure, a new fluoroscopy-based TAVI assistance system has been developed. The developed assistance system integrates a 3D geometrical aortic mesh model and anatomical valve landmarks with live 2D fluoroscopic images. The 3D aortic mesh model and landmarks are reconstructed from interventional angiographic and fluoroscopic C-arm CT system, and a target area of valve implantation is automatically estimated using these aortic mesh models. Based on template-based tracking approach, the overlay of visualized 3D aortic mesh model, landmarks and target area of implantation onto fluoroscopic images is updated by approximating the aortic root motion from a pigtail catheter motion without contrast agent. A rigid intensity-based registration method is also used to track continuously the aortic root motion in the presence of contrast agent. Moreover, the aortic valve prosthesis is tracked in fluoroscopic images to guide the surgeon to perform the appropriate placement of prosthesis into the estimated target area of implantation. An interactive graphical user interface for the surgeon is developed to initialize the system algorithms, control the visualization view of the guidance results, and correct manually overlay errors if needed. Retrospective experiments were carried out on several patient datasets from the clinical routine of the TAVI in a hybrid operating room. The maximum displacement errors were small for both the dynamic overlay of aortic mesh models and tracking the prosthesis, and within the clinically accepted ranges. High success rates of the developed assistance system were obtained for all tested patient datasets. The results show that the developed surgical assistance system provides a helpful tool for the surgeon by automatically defining the desired placement position of the prosthesis during the surgical procedure of the TAVI.Die Entwicklung bildgeführter interventioneller Systeme wächst rasant in den letzten Jahren. Diese neuen Systeme werden zunehmend ein wesentlicher Bestandteil der technischen Ausstattung bei modernen minimal-invasiven chirurgischen Eingriffen. Diese Entwicklung gilt besonders für die Herzchirurgie. Transkatheter Aortenklappen-Implantation (TAKI) ist eine neue entwickelte Operationstechnik zur Behandlung der schweren Aortenklappen-Stenose bei alten und Hochrisiko-Patienten. Die Platzierung der Aortenklappenprothese ist entscheidend und wird in der Regel unter live-2D-fluoroskopischen Bildgebung durchgeführt. Zur Unterstützung der Platzierung der Prothese während des chirurgischen Eingriffs wurde in dieser Arbeit ein neues Fluoroskopie-basiertes TAKI Assistenzsystem entwickelt. Das entwickelte Assistenzsystem überlagert eine 3D-Geometrie des Aorten-Netzmodells und anatomischen Landmarken auf live-2D-fluoroskopische Bilder. Das 3D-Aorten-Netzmodell und die Landmarken werden auf Basis der interventionellen Angiographie und Fluoroskopie mittels eines C-Arm-CT-Systems rekonstruiert. Unter Verwendung dieser Aorten-Netzmodelle wird das Zielgebiet der Klappen-Implantation automatisch geschätzt. Mit Hilfe eines auf Template Matching basierenden Tracking-Ansatzes wird die Überlagerung des visualisierten 3D-Aorten-Netzmodells, der berechneten Landmarken und der Zielbereich der Implantation auf fluoroskopischen Bildern korrekt überlagert. Eine kompensation der Aortenwurzelbewegung erfolgt durch Bewegungsverfolgung eines Pigtail-Katheters in Bildsequenzen ohne Kontrastmittel. Eine starrere Intensitätsbasierte Registrierungsmethode wurde verwendet, um kontinuierlich die Aortenwurzelbewegung in Bildsequenzen mit Kontrastmittelgabe zu detektieren. Die Aortenklappenprothese wird in die fluoroskopischen Bilder eingeblendet und dient dem Chirurg als Leitfaden für die richtige Platzierung der realen Prothese. Eine interaktive Benutzerschnittstelle für den Chirurg wurde zur Initialisierung der Systemsalgorithmen, zur Steuerung der Visualisierung und für manuelle Korrektur eventueller Überlagerungsfehler entwickelt. Retrospektive Experimente wurden an mehreren Patienten-Datensätze aus der klinischen Routine der TAKI in einem Hybrid-OP durchgeführt. Hohe Erfolgsraten des entwickelten Assistenzsystems wurden für alle getesteten Patienten-Datensätze erzielt. Die Ergebnisse zeigen, dass das entwickelte chirurgische Assistenzsystem ein hilfreiches Werkzeug für den Chirurg bei der Platzierung Position der Prothese während des chirurgischen Eingriffs der TAKI bietet

Role of computed tomography imaging for transcatheter valvular repair/insertion

During the last decade, the development of transcatheter based therapies has provided feasible therapeutic options for patients with symptomatic severe valvular heart disease who are deemed inoperable. The promising results of many nonrandomized series and recent landmark trials have increased the number of percutaneous transcatheter valve procedures in high operative risk patients. Pre-procedural imaging of the anatomy of the aortic or mitral valve and their spatial relationships is crucial to select the most appropriate device or prosthesis and to plan the percutaneous procedure. Multidetector row computed tomography provides 3-dimensional volumetric data sets allowing unlimited plane reconstructions and plays an important role in pre-procedural screening and procedural planning. This review will describe the evolving role of multidetector row computed tomography in patient selection and strategy planning of transcatheter aortic and mitral valve procedures

The ongoing impact of COVID-19 on adult cardiac surgery and suggestions for safe continuation throughout the pandemic:a review of expert opinions

OBJECTIVES: To establish the impact of the COVID-19 pandemic on adult cardiac surgery by reviewing current data and use this to establish methods for safely continuing to carry out surgery. METHODS: Conduction of a literature search via PubMed using the search terms: ‘(adult cardiac OR cardiothoracic OR surgery OR minimally invasive OR sternotomy OR hemi-sternotomy OR aortic valve OR mitral valve OR elective OR emergency) AND (COVID-19 or coronavirus OR SARS-CoV-2 OR 2019-nCoV OR 2019 novel coronavirus OR pandemic)’. Thirty-two articles were selected. RESULTS: Cardiac surgery patients have an increased risk of complications from COVID-19 and require vital finite resources such as intensive care beds, also required by COVID-19 patients. Thus reducing their admission and potential hospital-acquired infection with COVID-19 is paramount. During the peak, only emergencies such as acute aortic dissections were treated, triaging patients according to surgical priority and cancelling all elective procedures. Screening and 2-week quarantine prior to admission were essential changes, alongside additional levels of PPE. Focus was on reducing length of stay and switching to day-cases to reduce post-operative transmission risk, whilst several hospitals adopted ‘hot’ and ‘cold’ operating theatres for covid-confirmed and covid-negative patients. CONCLUSIONS: This paper suggests a ‘CARDIO’ approach for reintroducing elective procedures: ‘Care, Assess, Re-Evaluate, Develop, Implement, Overcome’; prioritising the mental and physical health of the workforce, learning from and sharing experiences and objectively prioritising patients to improve case load

Reoperative valve surgery: A Retrospective analysis of last ten years

INTRODUCTION: Extensive advances have been made in cardiac valve surgery since the first artificial valve replacements of the early 1950s. Improved survival after the first operation has meant that more patients ultimately require a redo operation at the same site and the number of patients will continue to increase as the general population ages. This trend reflects many factors, such as the increased life expectancy of the population, the decreased overall mortality associated with valvular surgery, and the increasing use of bioprostheses which have limited durability because of structural dysfunction. Hence reoperations are an integral part of the cardiac surgeon’s current daily practice. Among heart valves case load, re-operations on prostheses represent between 2.5% and 17%. AIMS AND OBJECTIVES: 1. To retrospectively evaluate our experience in patients who underwent re-operative valve surgery in our institution between January 2000 and December 2009 (a period of ten years). 2. To study their manner of presentation, the reasons leading to reoperation, the type of surgery performed and operative techniques. 3. To identify the risk factors for early mortality and morbidity associated with these operations. 4. To study the incidence of late morbidity and functional class at last follow-up. MATERIAL AND METHODS: This is a retrospective study of patients who underwent re-operative valve surgery between January 2000 and December 2009 in the Department of cardiothoracic surgery. In this period, a total of 43 underwent a first reoperation for a new valve problem of the native/prosthetic valve. There were 5 operative (30 days) mortalities (11.62%). A retrospective review of the hospital inpatient and outpatient charts of the rest of the 38 patients for their age, sex, presenting symptoms, preoperative NYHA class, preoperative risk factors, echocardiogram reports and operative details including surgical approach, total aortic cross clamp time, total cardio-pulmonary bypass time, post operative need for inotropes and ventilation, number of days of ICU care, post operative complications and post operative follow up was performed.(See appendix for proforma of data collection). Six patients were lost in the follow-up. Patients who had undergone a previous open heart surgery for varied etiologies were included in the study. Coronary angiogram was done in all patients older than 40 years. CONCLUSION: In conclusion, we have shown in this small series that repeat heart valve surgery can be performed with an acceptable operative mortality that compares favorably with results in other published series. However, several categories of patients have an increased risk of death at reoperation. These include patients with higher NYHA class, surgical priority, presence of infective endocarditis, preoperative renal dysfunction, Presence of CCF, preoperative LV function, previous surgery, present indication for reoperation and total CPB time. In addition, the indication for reoperation, especially thrombosed valves or prosthetic valve endocarditis, carries an increased risk. It is important that patients with prosthetic valves undergo regular follow-up with assessment of valve function and should undergo earlier reoperation before severe ventricular dysfunction occurs. In spite of regular follow-up, it is noted that majority of patients present with severe symptoms at reoperation, which is a predictor of major adverse postoperative event, including death, after valve reoperation. Hence, surgery should be considered early in the management of recurrent or progressive cardiac disease before severe symptoms develop and compromise the outcome of reoperation. In patients undergoing re-operative surgery, our unit protocol is to establish cardiopulmonary bypass before resternotomy and this is a valid and reproducible option to render cardiac reoperations safer and more expeditious in the reentry phase. The absence of cannulae in the operating field makes the procedure more comfortable. The liberal use of this strategy is recommended in redo cases is recommended. In our experience, there was no single instance of catastrophic hemorrhage and also it results in decreased total operative times and also decreased need for blood transfusions. No patient experienced complications related to femoral cannulation. The Seldinger method allowed little vascular trauma and intraoperative patency of femoral vessels. Reoperative surgery continues to pose a significant challenge to the entire cardiothoracic team. Careful patient selection and assessment, a tailored strategy based on accurate risk stratification, and a team approach in the perioperative period can decrease the incidence of adverse events, reducing morbidity and mortality. Further minimization of the risk is obtained by strict adherence to sound basic surgical principles and techniques. Generally speaking, optimal planning for reoperation prior to deterioration to NYHA class III–IV levels and before unfavorable co-morbid conditions have arisen is imperative to ensure good outcomes. Following these guidelines in the modern era, elective reoperative surgery can be performed with results similar to those of the primary operation

Stakeholders of Cardiovascular Innovation Ecosystems in Germany: A First Level Analysis and an Example

This paper aims to provide a first attempt towards analysis innovation ecosystems for cardiovascular pathologies in Germany through the use of a stakeholder model. We present essential stakeholders for the development and deployment of innovations in the field of cardiovascular research and medicine, and the primary functions they fulfill in the context of these innovation ecosystems. The adopted approach consists of the implementation of a multilevel system model for analyzing stakeholders in this particular field. Data acquisition transpired through systematic literature review of multiple articles and studies. Data analysis phases were executed until reaching a point at which the considerable amount of data was discovered, ensuring consistency across various sources. We demonstrate that innovation ecosystems in cardiovascular medicine involve interconnected networks of stakeholders across different fields. Moreover, through an investigation of innovation ecosystems of cardiovascular pathologies particularly in Germany, we present the functions undertaken by each stakeholder, which are essential for the participation in the innovation ecosystems. The findings presented in this paper hold the potential to bring better understanding of cardiovascular pathology innovation ecosystems in Germany. This assertion is substantiated through a comprehensive examination of relevant scientific literature