Coronary Connector Facilitated Total Endoscopic Coronary Artery Bypass: An Ex Vivo Feasibility Study.

Objective: Totally endoscopic coronary artery bypass (TECAB) procedures pose significant challenges, motivating the development of Octocon, an automated endoscopic connector designed for coronary anastomoses in off-pump and endoscopic settings. This feasibility study aimed to assess Octocon's functionality and maneuverability in closed-chest conditions during robot-assisted TECAB simulations.

Methods: The Octocon deployment comprises a 3-step procedure.

Evaluation of pliable bioresorbable, elastomeric aortic valve prostheses in sheep during 12 months post implantation.

Pliable microfibrous, bioresorbable elastomeric heart valve prostheses are investigated in search of sustainable heart valve replacement. These cell-free implants recruit cells and trigger tissue formation on the valves in situ. Our aim is to investigate the behaviour of these heart valve prostheses when exposed to the high-pressure circulation.

Strategies to Improve Survival from Surgery for Heart Valve Implantation in Sheep.

Sheep are a commonly used and validated model for cardiovascular research and, more specifically, for heart valve research. Implanting a heart valve on the arrested heart in sheep is complex and is often complicated by difficulties in restarting the heart, causing significant on-table mortality. Therefore, optimal cardioprotective management during heart valve implantation in sheep is essential.

In Situ Remodeling Overrules Bioinspired Scaffold Architecture of Supramolecular Elastomeric Tissue-Engineered Heart Valves.

In situ tissue engineering that uses resorbable synthetic heart valve scaffolds is an affordable and practical approach for heart valve replacement; therefore, it is attractive for clinical use. This study showed no consistent collagen organization in the predefined direction of electrospun scaffolds made from a resorbable supramolecular elastomer with random or circumferentially aligned fibers, after 12 months of implantation in sheep. These unexpected findings and the observed intervalvular variability highlight the need for a mechanistic understanding of the long-term in situ remodeling processes in large animal models to improve predictability of outcome toward robust and safe clinical application.

Failure of decellularized porcine small intestinal submucosa as a heart valved conduit.

Objective: Decellularized extracellular matrix made from porcine small intestinal submucosa, commercially available as CorMatrix (CorMatrix Cardiovascular, Inc, Roswell, Ga) is used off-label to reconstruct heart valves. Recently, surgeons experienced failures and words of caution were raised. The aim of this study was to evaluate decellularized porcine small intestinal submucosa as right-sided heart valved conduit in a xenogeneic animal model.

Added Value of Interactive 3-D Stereo Vision Echocardiography in the Heart Valve Team: A Post Hoc Analysis for Optimal Decision Making in Patients With Mitral Valve Regurgitation.

Objective: We assessed the added value of advanced echocardiography post hoc analysis for optimal decision-making in the Heart Valve Team (HVT) using an interactive, dynamic, live visualization system with true three-dimensional (3-D) stereo vision.

Methods: HVT scrutinized the incremental value of 3 consecutive methods of presentation of full-volume echocardiographic data sets in terms of diagnosis and possibility of repair in 11 selected patients having mitral regurgitation (MR)(Table 1). The questionnaire investigated consecutively (a) standard two-dimensional (2-D) transesophageal echocardiography, (b) single-beat 3-D zoom of the surgical view of the mitral valve, and (c) advanced 3-D volumetric rendering technology (Personal Space Station, Vesalius 3D software, PS-Medtech, Netherlands).

The early days of vascular and heart valve prostheses: a historical review.

This surgical heritage article provides a historical overview of the most important early advances of vascular- and valvular surgery, that lead to the development of currently used vascular- and valvular prostheses and materials. The first writings describing techniques in vascular surgery mainly focussed on hemorrhage control and date from around 1600 B.C.

A Novel Cardiovascular Prosthesis Made from Woven Ultrahigh-Molecular-Weight Polyethylene Fibers, Proof of Concept in a Sheep Model.

Background: A patch made of woven ultrahigh-molecular-weight polyethylene (UHMWPE) fibers is thin, strong, and flexible and may be attractive for use in cardiovascular prostheses. This study assessed the hemocompatibility of this patch in a sheep model.

Methods: The UHMWPE patches were sutured in the right carotid artery and jugular vein in 12 adult sheep, and in the same animal, expanded polytetrafluoroethylene (ePTFE) patches were sutured as control patches in the left carotid artery and jugular vein.

Flexible mechanoprosthesis made from woven ultra-high-molecular-weight polyethylene fibres: proof of concept in a chronic sheep model.

Objectives: Ultra-high-molecular-weight polyethylene (UHMWPE) fibres are flexible, have high tensile strength, and platelet and bacterial adhesion is low. Therefore, UHMWPE may overcome limitations of current mechanical valves and bioprostheses. In this study, the biocompatibility and functionality of prototype handmade stented valves from woven UHMWPE (U-valve) was assessed in a chronic sheep model with acetylsalicylic acid monotherapy.

Adherence of Staphylococcus aureus to Dyneema Purity® Patches and to Clinically Used Cardiovascular Prostheses.

Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for prostheses is Dyneema Purity®, made of ultra-high-molecular-weight polyethylene.

The "Spacemaker", a New Device for Minimally Invasive Cardiothoracic Surgery: An Evaluation and Feasibility Study.

Objective: Our aim was to evaluate a new inflatable lung retractor, the "Spacemaker", and its efficacy in facilitating minimally invasive cardiothoracic surgery without the need of one lung ventilation or carbon dioxide overpressure insufflation.

Methods: The device was tested in 12 anesthetized pigs (90-100 kg) placed on standard endotracheal ventilation. The device was introduced into the right or left side of the chest, depending on the intended procedure to be performed, via a 3-cm incision in the fifth intercostal space.

In Vitro Hemocompatibility Testing of Dyneema Purity Fibers in Blood Contact.

Objective: Heart valve and vascular prosthesis implantation is a common procedure for patients with heart valve stenosis or regurgitation and dilated or obstructive vascular disease. Drawbacks of conventional valve prostheses are the requirement for anticoagulant drugs, moderate durability, and suboptimal resistance to fatigue and tear. Dyneema Purity fibers are made from ultra-high-molecular-weight polyethylene filaments and are very thin, flexible, and fatigue and abrasion resistant and have high strength.

Mitral valve annuloplasty rings: review of literature and comparison of functional outcome and ventricular dimensions.

In the past decades, more than 40 mitral valve annuloplasty rings of various shapes and consistency were marketed for mitral regurgitation (MR), although the effect of ring type on clinical outcome remains unclear. Our objective was to review the literature and apply a simplification method to make rings of different shapes and rigidity more comparable. We studied relevant literature from MEDLINE and EMBASE databases related to clinical studies as well as animal and finite element models.

Myocardial infarction and functional outcome assessment in pigs.

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One important prerequisite is a good understanding of all safety and efficacy aspects obtained in a large animal model that validly reflect the human scenario of myocardial infarction (MI). Pigs are widely used in this regard since their cardiac size, hemodynamics, and coronary anatomy are close to that of humans.

Surgical left ventricular radius enlargement by patch insertion on the beating heart: a new experimental aneurysm model.

We presented a novel experimental aneurysm model for studies in left ventricular (LV) reconstruction techniques and assessed LV function. In eight pigs, the LV radius and geometry were enlarged surgically on the beating heart by inserting an aortic allograft construct. Haemodynamics and LV dimensions were assessed by echocardiography at baseline and under dobutamine stress.

Myocardial lesion depth with circular electroporation ablation.

Background: Recently, we demonstrated the feasibility and safety of circular electroporation ablation in porcine pulmonary vein ostia, but the relationship between the magnitude of the application and lesion dimensions is still unknown.

Methods And Results: An in vivo porcine study was performed on left ventricular epicardium submerged under 10 mm of blood, using devices that mimic a 20-mm-diameter 7F circular ablation catheter. Model D contained 10 separate electrodes, whereas model M consisted of 1 circular electrode.

In-vivo validation of a new non-invasive continuous ventricular stroke volume monitoring system in an animal model.

Introduction: Recently, a non-invasive, continuous ventricular stroke volume monitoring system using skin electrodes has been developed. In contrast to impedance-based methods, the new technique (ventricular field recognition) enables measurement of changes in ventricular volume. A prototype using this new method was built (the hemologic cardiac profiler, HCP) and validated against a reference method in a pig model during variations in cardiac output.

Computed tomography detects tissue formation in a stented engineered heart valve.

Tissue-engineered heart valves (TEHV) are being explored as an alternative to conventional heart valve prostheses. Using the classic tissue engineering paradigm, a stented tri-leaflet valve is fabricated. Subsequently, the construct is implanted into the pulmonary position in a sheep.

Feasibility of electroporation for the creation of pulmonary vein ostial lesions.

Introduction: There is an obvious need for a better energy source for pulmonary vein (PV) antrum isolation.

Objective: We investigated the feasibility and safety of electroporation for the creation of PV ostial lesions.

Methods: After transseptal puncture, a custom 7F decapolar 20 mm circular ablation catheter was placed in the PV ostia of 10 pigs.

Resizable ventricular patch plasty in the porcine left ventricle: a pilot study.

Objective: : Endoventricular circular patch plasty is a method used to reconstruct the ventricular cavity in patients with (post) ischemic left ventricular aneurysm or global dilatation. However, late redilatation with mitral regurgitation has been reported, in which postoperative apex shape seems to play an important role. We studied the feasibility of ventricular volume downsizing with a variably shaped patch in porcine hearts.

Translating autologous heart valve tissue engineering from bench to bed.

Tissue engineering is currently being actively investigated to ascertain if it can offer an alternative to prosthetic aortic heart valves that may overcome the current limitations of prosthetic aortic heart valves while at the same time conferring the advantages of a living autologous structure, such as biocompatibility, the capacity to grow, repair, and remodel. In vitro studies have shown tissue-engineered heart valves to have adequate structural and functional properties, indicating a promising future for heart valve tissue engineering. However, criteria are required to be able to evaluate autologous heart valves and to deem them satisfactory for clinical use.

Stability of an autologous platelet clot in the pericardial sac: An experimental and clinical study.

Objective: Autologous platelet clots serve as slow-release delivery systems for platelet-derived growth factors and cytokines. Their application to the pericardial sac might facilitate salvage and repair of ischemically injured myocardium. However, little is known about platelet clot stability in the pericardial sac.

High-frequency epicardial ultrasound: review of a multipurpose intraoperative tool for coronary surgery.

Background: In open-chest coronary artery bypass grafting (CABG), the surgeon faces several intraoperative challenges: (1) to locate the target coronary artery, (2) to select the optimal anastomotic site, and (3) to assess the quality of the graft and distal anastomosis. Endoscopically, these three diagnostic aims are particularly challenging.

Methods: We reviewed the literature on the intraoperative application of high-frequency (6.

Robot-assisted 13 MHz epicardial ultrasound for endoscopic quality assessment of coronary anastomoses.

In totally endoscopic coronary artery bypass surgery, intra-operative assessment of anastomotic quality is needed. We evaluated the endoscopic application of epicardial ultrasound to visualize the coronary anastomosis and detect a construction error. In 8 pigs (71-78kg), 16 internal mammary artery to left anterior descending coronary artery anastomoses were constructed conventionally, either correctly (n=8) or incorrectly with a suture cross-over construction error (n=8).