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Medical and Biological Applications of Low Energy Accelerators
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
In the case of artificial heart valves, there is an urgent need for developing alternative heart valves to overcome long-term stability and biocompatibility issues that are associated with artificial heart valves. The main challenge faced by material engineers is to create new, self-healing materials that can offer adequate mechanical properties for highly dynamic biological environments. While various self-healing materials have been developed, none so far has been used for the fabrication of heart valves.
Living Donors, Non-Human Sources, and Cadaveric Donors
Published in David Lamb, Organ Transplants and Ethics, 2020
Since earliest times the infirm have resorted to sticks and crutches to get about. Crutches were replaced by wooden legs; wheelchairs and invalid carriages were designed to help those afflicted by various infirmities which restricted mobility; hooks were attached to arms to act as substitutes for severed hands; and further refinements to artificial limbs have accompanied technological developments throughout the centuries. Artificial teeth have been used throughout the history of dentistry, and devices to improve vision can be traced back as far as the Roman Empire. From ear trumpets in the nineteenth century have come sophisticated hearing aids, using computer technology, which also offers a great many devices to aid the handicapped. In the early post-war years there was great enthusiasm for iron lungs, rocking beds and walking braces as a means of restoring to a child with infantile paralysis some meaningful level of life. Arthritic hips, elbows, shoulders, knees, ankles, fingers, toes, as well as penises and breasts, are today routinely replaced by artificial ones. Internal replacements include heart pacemakers, and artificial heart valves made of metal and plastic are frequently implanted. Over 100,000 silicon implants are performed each year. Current research promises spectacular future developments. Work is well under way on artificial eyes for the blind consisting of a small TV capable of transmitting images to a miniature computer that would then send them (through electrodes implanted in the head) to the brain’s visual cortex.
Pharmaceutical and Medical Device Product Liability Litigation
Published in Julie Dickinson, Anne Meyer, Karen J. Huff, Deborah A. Wipf, Elizabeth K. Zorn, Kathy G. Ferrell, Lisa Mancuso, Marjorie Berg Pugatch, Joanne Walker, Karen Wilkinson, Legal Nurse Consulting Principles and Practices, 2019
Vicki W. Garnett, Stacy Newsome
One of the known risks of the artificial heart valve is thrombogenicity, or risk of clot formation. Because the artificial heart valve is a foreign object and does not have the hemodynamics of a natural heart valve, thrombosis formation will occur in a certain number of patients. Thrombosis, as a result of artificial heart valve replacement, is considered a reasonable risk and if thrombosis does occur (in most cases) the valve would not be considered unreasonably dangerous or defective.
The evolution of long-term pediatric ventricular assistance devices: a critical review
Published in Expert Review of Medical Devices, 2021
Louis Marcel, Mathieu Specklin, Smaine Kouidri
At first, designers’ objective was to replicate the native cardiac cycle using a diaphragm or pusher plate delivering pulsatile flow through unidirectional and artificial heart valves. Figure 6 shows the mechanical structure of these devices. Thanks to a flexible diaphragm whose vertical displacement is imposed by the pusher plate, the blood is compressed in the pumping chamber until the pressure is superior to the one in the outflow. At this moment, the outflow valve opens and the blood is re-injected in the aorta. Pressure decreases as the pusher plate comes back down. Pressure value becomes inferior than the inflow resulting in the opening of the inflow valve and the pumping chambers is filled back with blood. The devices was filled during diastole and communicate the energy to the fluid by ejecting it during systole, this is a device working in co-pulsation [56]. These pumps were reported by Frazier et al. as similar in operation as the human heart thanks to the pulsatile outflow generated [57]. This pump generation was also characterized by their large dimensions and heavy external driving units, limiting the patient’s mobility. Unfortunately, the technology was not very reliable on the long term as most of them presented global pump dysfunction leading to right heart failure, renal dysfunction and neurologic adverse events after a year of support according to clinicians. These drawbacks and the lack of reliability in the technology led to the development of devices based on a rotating impeller [58].
Biointerface: a nano-modulated way for biological transportation
Published in Journal of Drug Targeting, 2020
Pravin Shende, Varun S. Wakade
The interaction between blood platelet and biomaterial surface plays a fundamental role in the preparation of artificial heart valves, vascular stents and circulatory support devices. Surface wettability of cell-membrane is a vital parameter to increase the adhesion, which causes the activation of platelets. Blood contact device prevents cell-adhesion and activation of platelets [61]. The microtexture pattern decreases the platelet adhesion and improves blood compatibility [62]. Sun et al. conducted the study in which the platelets detach from CNT that lead to a decrease in platelet activation on polycarbonate urethane containing fluorinated alkyl side chain. Polycarbonate urethane coated on CNT causes super-hydrophobicity that reduces the contact area but improves surface blood compatibility. The decrease in adsorption and aggregation of the cell at the surface develops the concept as a novel approaches in drug delivery.
Acquired hemophilia A: when an overlooked autoimmune disorder causes significant bleeding
Published in Expert Opinion on Orphan Drugs, 2020
Layal Al Mahmasani, Antoine Finianos, Rayan Bou-Fakhredin, Joseph Elias, Ali Taher
Many patients require immediate treatment to control bleeding, but not all types of bleeding require intervention [5,25]. Therapy is required in patients with AHA who are undergoing invasive procedures (before and after the procedure) and in patients with major bleeding and/or have a decrease in hemoglobin level [3]. The decision to treat shall be taken based on the whole clinical picture. Appropriate treatment of patients with acquired inhibitors to factor VIII essentially depends on the natural history of any concomitant pathology and the clinical presentation of the coagulopathy [26]. For instance, in patients with cardiovascular comorbidities and advanced age, treatment using bypassing agents may increase the risk for thrombotic complications. Other risk factors for thromboembolic complications include the previous history of thrombosis, immobilization, malignancy, indwelling catheters, artificial heart valves, vascular grafts, atrial fibrillation, and pregnancy/postpartum [1]. For example, the risk has been reported to reach 7% in patients treated with recombinant factor VIIa, a bypassing agent [27].