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The Western Journal of Medicine Nov 1986
Topics: Heart, Artificial; Humans; Technology Assessment, Biomedical
PubMed: 3798918
DOI: No ID Found -
The British Journal of Radiology Feb 2015This article familiarizes the reader with several different cardiac devices including pacemakers and implantable cardioverter defibrillators, intra-aortic balloon pumps,... (Review)
Review
This article familiarizes the reader with several different cardiac devices including pacemakers and implantable cardioverter defibrillators, intra-aortic balloon pumps, ventricular assist devices, valve replacements and repairs, shunt-occluding devices and passive constraint devices. Many cardiac devices are routinely encountered in clinical practice. Other devices are in the early stages of development, but circumstances suggest that they too will become commonly found. The radiologist must be familiar with these devices and their complications.
Topics: Defibrillators, Implantable; Equipment Failure Analysis; Heart Diseases; Heart-Assist Devices; Humans; Pacemaker, Artificial; Radiography, Thoracic
PubMed: 25411826
DOI: 10.1259/bjr.20140540 -
ASAIO Journal (American Society For... 2017Development of tissue-engineered hearts for treatment of myocardial infarction or biologic pacemakers has been hindered by the production of mostly arrhythmic or...
Development of tissue-engineered hearts for treatment of myocardial infarction or biologic pacemakers has been hindered by the production of mostly arrhythmic or in-synergistic constructs. Electrical stimulation (ES) of these constructs has been shown to produce tissues with greater twitch force and better adrenergic response. To further our understanding of the mechanisms underlying the effect of ES, we fabricated a bioreactor capable of delivering continuous or intermittent waveforms of various types to multiple constructs simultaneously. In this study, we examined the effect of an intermittent biphasic square wave on our artificial heart muscle (AHM) composed of neonatal rat cardiac cells and fibrin gel. Twitch forces, spontaneous contraction rates, biopotentials, gene expression profiles, and histologic observations were examined for the ES protocol over a 12 day culture period. We demonstrate improved consistency between samples for twitch force and contraction rate, and higher normalized twitch force amplitudes for electrically stimulated AHMs. Improvements in electrophysiology within the AHM were noted by higher conduction velocities and lower latency in electrical response for electrically stimulated AHMs. Genes expressing key electrophysiologic and structural markers peaked at days 6 and 8 of culture, only a few days after the initiation of ES. These results may be used for optimization strategies to establish protocols for producing AHMs capable of replacing damaged heart tissue in either a contractile or electrophysiologic capacity. Optimized AHMs can lead to alternative treatments to heart failure and alleviate the limited donor supply crisis.
Topics: Animals; Bioreactors; Electric Stimulation; Gene Expression; Heart Failure; Heart, Artificial; Myocardial Contraction; Myocytes, Cardiac; Rats; Rats, Sprague-Dawley
PubMed: 28459744
DOI: 10.1097/MAT.0000000000000486 -
Hellenic Journal of Cardiology : HJC =... 2020Total artificial heart (TAH) is a viable bridge to transplant (BTT) strategy for patients with severe biventricular failure or complex congenital heart disease. These...
OBJECTIVE
Total artificial heart (TAH) is a viable bridge to transplant (BTT) strategy for patients with severe biventricular failure or complex congenital heart disease. These patients have higher mortality and morbidity than patients undergoing left ventricular assist device (LVAD) implantation. To assess national trends in in-hospital mortality, major complications, cost, length of stay, and disposition of patients undergoing TAH implantation.
METHODS
Data from the National Inpatient Sample, the largest all-payer inpatient data set in the United States, and the US Census Bureau, for the years 2009 to 2015 were analyzed. Participants included all adult patients who received TAH from 2009 to 2015. Endpoints included in-hospital mortality, in-hospital complications, heart transplantation (HT) in the same admission, length of stay, cost, and disposition at the time of discharge.
RESULTS
We identified a total of 143 (weighted = 703) TAH implantations. The number of TAH implants increased during the study period (average annual change +5.8%, p = 0.03). Rates of in-hospital mortality and major complications including ischemic stroke, major bleeding, postoperative infections, acute kidney injury requiring dialysis, and HT did not change significantly over the study period. Although the length of stay and disposition patterns did not change over time, we found a significant increase in cost of hospitalization (average annual change +44,362, p = 0.01). The number of HT during the same hospital stay decreased significantly (average annual change -8.1%, p = 0.02).
CONCLUSION
In-hospital mortality and complication rates associated with TAH implantation remain increased and did not change in the era of continuous flow LVADs.
Topics: Adult; Heart Failure; Heart Transplantation; Heart, Artificial; Heart-Assist Devices; Hospital Mortality; Humans; Retrospective Studies; United States
PubMed: 30790715
DOI: 10.1016/j.hjc.2019.02.002 -
Scientific Reports Apr 2023For those suffering from end-stage biventricular heart failure, and where a heart transplantation is not a viable option, a Total Artificial Heart (TAH) can be used as a...
For those suffering from end-stage biventricular heart failure, and where a heart transplantation is not a viable option, a Total Artificial Heart (TAH) can be used as a bridge to transplant device. The Realheart TAH is a four-chamber artificial heart that uses a positive-displacement pumping technique mimicking the native heart to produce pulsatile flow governed by a pair of bileaflet mechanical heart valves. The aim of this work was to create a method for simulating haemodynamics in positive-displacement blood pumps, using computational fluid dynamics with fluid-structure interaction to eliminate the need for pre-existing in vitro valve motion data, and then use it to investigate the performance of the Realheart TAH across a range of operating conditions. The device was simulated in Ansys Fluent for five cycles at pumping rates of 60, 80, 100 and 120 bpm and at stroke lengths of 19, 21, 23 and 25 mm. The moving components of the device were discretised using an overset meshing approach, a novel blended weak-strong coupling algorithm was used between fluid and structural solvers, and a custom variable time stepping scheme was used to maximise computational efficiency and accuracy. A two-element Windkessel model approximated a physiological pressure response at the outlet. The transient outflow volume flow rate and pressure results were compared against in vitro experiments using a hybrid cardiovascular simulator and showed good agreement, with maximum root mean square errors of 15% and 5% for the flow rates and pressures respectively. Ventricular washout was simulated and showed an increase as cardiac output increased, with a maximum value of 89% after four cycles at 120 bpm 25 mm. Shear stress distribution over time was also measured, showing that no more than [Formula: see text]% of the total volume exceeded 150 Pa at a cardiac output of 7 L/min. This study showed this model to be both accurate and robust across a wide range of operating points, and will enable fast and effective future studies to be undertaken on current and future generations of the Realheart TAH.
Topics: Heart, Artificial; Hemodynamics; Cardiovascular System; Heart Transplantation; Pulsatile Flow; Models, Cardiovascular; Prosthesis Design
PubMed: 37059748
DOI: 10.1038/s41598-023-32141-2 -
Interactive Cardiovascular and Thoracic... Jan 2022Although the activated partial thromboplastin time (aPTT) has historically been the method of choice for anticoagulation monitoring in patients undergoing mechanical...
Although the activated partial thromboplastin time (aPTT) has historically been the method of choice for anticoagulation monitoring in patients undergoing mechanical circulatory support with intravenous unfractionated heparin, it is being progressively superseded by the anti-factor Xa (anti-Xa) method. A retrospective single-arm, single-centre analysis of 20 patients who underwent total artificial heart implantation entailed simultaneous determinations of aPTT and anti-Xa. Agreement between these parameters was assessed using the Bland-Altman method. Despite a positive correlation between aPTT and anti-Xa, normal target ranges were poorly aligned: from 5th to 30th postoperative day, for anti-Xa values of 0.2 and 0.4 U/ml corresponding aPTT values were 52.1 and 65.2 s, 7.9 and 14.8 lower than predicted values, respectively. This was not associated with thromboembolic sequalae. It was not possible to demonstrate a significant relationship between the predictor variables (postoperative day; white blood cell count; C-reactive protein concentration; alanine transaminase and alkaline phosphatase level; bilirubin; haemoglobin; albumin and total protein concentration) and the agreement between aPTT and anti-Xa levels. In summary, when anti-Xa levels were used to guide anticoagulation therapy, corresponding aPTT levels were low with respect to target range. Methodology applied in this study is generalizable to other forms of mechanical circulatory support.
Topics: Anticoagulants; Drug Monitoring; Factor Xa Inhibitors; Heart, Artificial; Heparin; Humans; Partial Thromboplastin Time; Retrospective Studies
PubMed: 34849924
DOI: 10.1093/icvts/ivab251 -
Expert Review of Cardiovascular Therapy Apr 2015The pediatric ventricular assist device (VAD) has recently shown substantial improvements in survival as a bridge to heart transplant for patients with end-stage heart... (Review)
Review
The pediatric ventricular assist device (VAD) has recently shown substantial improvements in survival as a bridge to heart transplant for patients with end-stage heart failure. Since that time, its use has become much more frequent. With increasing utilization, additional questions have arisen including patient selection, timing of VAD implantation and device selection. These challenges are amplified by the uniqueness of each patient, the recent abundance of literature surrounding VAD use as well as the technological advancements in the devices themselves. Ideal strategies for device placement must be sought, for not only improved patient care, but also for optimal resource utilization. Here, we review the most relevant literature to highlight some of the challenges facing the heart failure specialist, and any physician, who will care for a child with a VAD.
Topics: Adolescent; Adult; Cardiomyopathy, Dilated; Child; Child, Preschool; Heart Defects, Congenital; Heart Failure; Heart Transplantation; Heart, Artificial; Heart-Assist Devices; Humans; Infant; Myocarditis; Treatment Outcome; Young Adult
PubMed: 25732410
DOI: 10.1586/14779072.2015.1021786 -
Journal of Biomechanics Jan 2013Recent computational methods enabling patient-specific simulations of native and prosthetic heart valves are reviewed. Emphasis is placed on two critical components of... (Review)
Review
Recent computational methods enabling patient-specific simulations of native and prosthetic heart valves are reviewed. Emphasis is placed on two critical components of such methods: (1) anatomically realistic finite element models for simulating the structural dynamics of heart valves; and (2) fluid structure interaction methods for simulating the performance of heart valves in a patient-specific beating left ventricle. It is shown that the significant progress achieved in both fronts paves the way toward clinically relevant computational models that can simulate the performance of a range of heart valves, native and prosthetic, in a patient-specific left heart environment. The significant algorithmic and model validation challenges that need to be tackled in the future to realize this goal are also discussed.
Topics: Algorithms; Computer Simulation; Female; Finite Element Analysis; Heart Valves; Heart Ventricles; Heart, Artificial; Humans; Male; Models, Cardiovascular
PubMed: 23174421
DOI: 10.1016/j.jbiomech.2012.10.026 -
Swiss Medical Weekly 2011Severe heart failure and cerebral stroke are broadly associated with the impairment of muscular function that conventional treatments struggle to restore. New... (Review)
Review
Severe heart failure and cerebral stroke are broadly associated with the impairment of muscular function that conventional treatments struggle to restore. New technologies enable the construction of "smart" materials that could be of great help in treating diseases where the main problem is muscle weakness. These materials "behave" similarly to biological systems, because the material directly converts energy, for example electrical energy into movement. The extension and contraction occur silently like in natural muscles. The real challenge is to transfer this amazing technology into devices that restore or replace the mechanical function of failing muscle. Cardiac assist devices based on artificial muscle technology could envelope a weak heart and temporarily improve its systolic function, or, if placed on top of the atrium, restore the atrial kick in chronic atrial fibrillation. Artificial sphincters could be used to treat urinary incontinence after prostatectomy or faecal incontinence associated with stomas. Artificial muscles can restore the ability of patients with facial paralysis due to stroke or nerve injury to blink. Smart materials could be used to construct an artificial oesophagus including peristaltic movement and lower oesophageal sphincter function to replace the diseased oesophagus thereby avoiding the need for laparotomy to mobilise stomach or intestine. In conclusion, in the near future, smart devices will integrate with the human body to fill functional gaps due to organ failure, and so create a human chimera.
Topics: Animals; Artificial Organs; Biomimetics; Heart Failure; Heart-Assist Devices; Humans; Muscle Weakness; Muscles; Polymers; Urinary Sphincter, Artificial
PubMed: 22180171
DOI: 10.4414/smw.2011.13311 -
Medicina (Kaunas, Lithuania) Oct 2020: The understanding of high body mass index (BMI) and outcomes after Left Ventricular Assist Device (LVAD) implantation continues to evolve and the relationship has not...
: The understanding of high body mass index (BMI) and outcomes after Left Ventricular Assist Device (LVAD) implantation continues to evolve and the relationship has not been established yet. In this study, we investigated the effects of obesity (BMI > 30 kg/m) on post-LVAD implantation outcomes. HeartWare LVAD and Heart Mate III LVAD were implanted. The primary outcome that was measured was mortality (in-hospital and on follow-up). The secondary outcomes that were measured were major adverse events. At our institution, the West German Heart and Vascular Center (Essen, Germany), from August 2010 to January 2020, a total of 210 patients received a long-term LVAD. Patients were stratified according to BMI ≥ 30 kg/m representing the obesity threshold. The first group ( = 162) had an average BMI of 24.2 kg/m (±2.9), and the second group ( = 48) had an average BMI of 33.9 kg/m (±3.2). Baseline demographics were analysed alongside comorbidities per group. Overall mortality was not significantly different between the obese group (51.1% = 24) and the nonobese group (55.2%, = 85) ( = 0.619). The difference between the mean duration of survival of patients who expired after hospital discharge was insignificant (2.1 years ± 1.6, group 1; 2.6 years ± 1.5, group 2; = 0.29). In-hospital mortality was unvaried between the two groups: group 1: = 34 (44% out of overall group 1 deaths); group 2: = 11 (45.8% out of overall group 2 deaths) ( > 0.05). Postoperative complications were unvaried between the obese and the non-obese group (all with > 0.05). However, a significant difference was found with regards to follow-up neurological complications (18.5% vs. 37.8%, = 0.01) and LVAD thrombosis (14.7% vs. 33.3%, = 0.01), as both were higher in the obese population. Obesity does not form a barrier for LVAD implantation in terms of mortality (in-hospital and on follow up). However, a significantly higher incidence of follow-up LVAD thrombosis and neurological complications has been found in the obese group of patients.
Topics: Body Mass Index; Germany; Heart Failure; Heart-Assist Devices; Humans; Obesity; Retrospective Studies; Treatment Outcome
PubMed: 33113962
DOI: 10.3390/medicina56110556