Evolution of Artificial Hearts: An Overview and History

Review of Systemic Mock Circulation Loops for Evaluation of Implantable Cardiovascular Devices and Biological Tissues

CLINICAL IMPACT

On needs-based ex vivo monitoring of implantable devices or tissues/organs in cardiovascular simulators provides new insights and paves new paths for device prototypes. The insights gained could not only support the needs of patients, but also inform engineers, scientists and clinicians about undiscovered aspects of diseases (during routine monitoring). We analyze seminal and current work and highlight a variety of opportunities for developing preclinical tools that would improve strategies for future implantable devices. Holistically, mock circulation loop studies can bridge the gap between in vivo and in vitro approaches, as well as clinical and laboratory settings, in a mutually beneficial manner.

Five historical innovations that have shaped modern cardiothoracic surgery

Throughout history, many innovations have contributed to the development of modern cardiothoracic surgery, improving patient outcomes and expanding the range of treatment options available to patients. This article explores five key historical innovations that have shaped modern cardiothoracic surgery: cardiopulmonary bypass, surgical pacemakers, video assisted thoracic surgery, robotic surgery and mechanical circulatory support. We will review the development, impact and significance of each innovation, highlighting their contributions to the field of cardiothoracic surgery and their ongoing relevance in contemporary and perioperative practice.

Self-regulating electrical rhythms with liquid crystal oligomer networks in hybrid circuitry

Self-regulation is an essential aspect in the practicality of electronic systems, ranging from household heaters to robots for industrial manufacturing. In such devices, self-regulation is conventionally achieved through separate sensors working in tandem with control modules. In this paper, we harness the reversible actuating properties of liquid crystal oligomer network (LCON) polymers to design a self-regulated oscillator. A dynamic equilibrium is achieved by applying a thermally-responsive and electrically-functionalized LCON film as a dual-action component, namely as a combined electrical switch and composite actuating sensor, within a circuit. This hybrid circuit configuration, consisting of both inorganic and organic material, generates a self-regulated feedback loop which cycles regularly and indefinitely. The feedback loop cycle frequency is tunable between approximately 0.08 and 0.87 Hz by altering multiple factors, such as supplied power or LCON chemistry. Our research aims to drive the material-to-device transition of stimuli-responsive LCONs, striving towards applications in electronic soft robotics.

Total artificial heart as a bridge to transplantation

PURPOSE OF REVIEW

Since the first implantation of a total artificial heart (TAH) 50 years ago the devices and technique have evolved to provide reliable support for patients with biventricular failure as a bridge to heart transplant. The purpose of this review is to discuss the history and evolution of devices, current devices, critical aspects of patient selection, tips and pitfalls of implantation, and future directions.

RECENT FINDINGS

The most studied device on the market is the SynCardia TAH, which has been implanted in over 2000 patients worldwide and is the only device that is currently Food and Drug Administration approved as a bridge to transplant. The overall survival in patients supported by the device at 1 year is 42% while those that make it to transplant have a 1 year post transplant survival of 83%. A newer device the Aeson TAH (Carmat, Velizy-Villacoublay, France) was first implanted in France in 2013 and is currently under clinical trial in the United States.

SUMMARY

Significant progress has been made in both the technology and technique of TAH implantation and these devices remain both a reliable and sometimes only option for patients with severe biventricular heart failure.

A Dilemma for Respecting Autonomy: Bridge Technologies and the Hazards of Sequential Decision-Making

Respect for patient autonomy can apply at two levels: ensuring that patient care reflects their considered values and wishes and honoring patient preferences about how to make momentous decisions. Caregivers who seek to respect patient autonomy in the context of some end-of-life decisions face a dilemma. Because these decisions are fraught, patients may prefer to approach them sequentially, only making decisions at the time they arise. However, respecting patients' preferences for a sequential approach can increase the likelihood that surrogates and care teams wind up in situations in which they lack information needed to ensure patients receive care that conforms to their considered values after they are no longer competent to make decisions for themselves. Sequential decision-making can thus conflict with the goal of ensuring care reflects the wishes of patients. After illustrating how this dilemma can arise in the use of life-sustaining "bridge" technologies, we argue that care teams may be warranted in requiring patients to articulate their wishes in an advance care plan before treatment begins. In some cases, care teams may even be permitted to refuse to undertake certain courses of care, unless patients articulate their wishes in an advance care plan.

Virtual reality-guided left ventricular assist device implantation in pediatric patient: Valuable presurgical tool

Virtual reality (VR) is increasingly used for presurgical planning and teaching during surgery. However, VR aided presurgical planning toolbox for left ventricular assist device (LVAD) implantation is not widely available. We investigated the use of a VR environment with wearable headsets and touch controllers in simulating an implant in an 11-year-old boy. The technology played a significant role in the optimal positioning of the LVAD.

Preliminary Computational Analysis of Three Configurations for an Innovative Ventricular Chamber

(1) Background: shape, dimension, hemodynamics, and hemocompatibility are just a few of the several challenging key points that must be addressed in designing any suitable solution for the ventricular chamber of mechanical circulatory support devices. A preliminary evaluation of different geometries of bellow-like ventricular chambers is herein proposed. The chambers were made with a polycarbonate urethane that is acknowledged to be a hemocompatible polymer. (2) Methods: an explicit dynamic computational analysis was performed. The actuation of the three chambers was simulated without the presence of an internal fluid. Maximum stress and strain values were identified, as well as the most critical regions. Geometric changes were checked during simulated motion to verify that the dimensional constraints were satisfied. (3) Results: one chamber appeared to be the best solution compared to the others, since its dimensional variations were negligible, and effective stresses and strains did not reach critical values. (4) Conclusions: the identification of the best geometric solution will allow proceeding with further experimental studies. Fluid–structure interactions and fatigue analyses were investigated.

Clinically advancing and promising polymer-based therapeutics

In this review article, we will examine the history of polymers and their evolution from provisional World War II materials to medical therapeutics. To provide a comprehensive look at the current state of polymer-based therapeutics, we will classify technologies according to targeted areas of interest, including central nervous system-based and intraocular-, gastrointestinal-, cardiovascular-, dermal-, reproductive-, skeletal-, and neoplastic-based systems. Within each of these areas, we will consider several examples of novel, clinically available polymer-based therapeutics; in addition, this review will also include a discussion of developing therapies, ranging from the in vivo to clinical trial stage, for each targeted area of treatment. Finally, we will emphasize areas of patient care in need of more effective, accessible, and targeted treatment approaches where polymer-based therapeutics may offer potential solutions.