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"Cardiovascular instruments, Implanted."
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Ticker : the quest to create an artificial heart
\"Swartz takes readers on [a] ... behind-the-scenes journey into a heart surgeon's ... quest to develop an artificial heart--a reliable, implantable device that would extend the lives of patients who have no other recourse ... Chronicling the evolution of cardiac medicine, from pioneering efforts in open heart surgery and bypass operations under Michael DeBakey and Denton Cooley, to the advent of valve replacement and heart transplants, and protege Bud Frazier's introduction of the Left Ventricle Assist Device (or LVAD) ... Swartz follows Frazier and his partner Billy Cohn as they ... design, develop, and test new heart designs\"--Provided by publisher.
Book
Fully bioresorbable vascular scaffolds: lessons learned and future directions
Fully bioresorbable scaffolds (BRS) were designed to overcome the limitations of metallic drug-eluting stents, but long-term results with these devices have been disappointing. In this Review, the authors discuss the available preclinical and clinical data for BRS and how this information can inform the development of next-generation BRS.
Journal Article
A shear gradient–dependent platelet aggregation mechanism drives thrombus formation
Warwick Nesbitt, Erik Westein and coworkers describe a new mechanistic model for thrombus growth within a blood vessel, providing evidence that blood flow shear gradients—which can arise from vessel injury, stenosis or obstruction—are important in driving thrombus formation. Rapid changes in blood shear rates lead to dynamic restructuring of membranous structures, called 'tethers', on the platelet surface, facilitating stable platelet deposition onto a growing thrombus (
pages 607–608
).
Platelet aggregation at sites of vascular injury is essential for hemostasis and arterial thrombosis. It has long been assumed that platelet aggregation and thrombus growth are initiated by soluble agonists generated at sites of vascular injury. By using high-resolution intravital imaging techniques and hydrodynamic analyses, we show that platelet aggregation is primarily driven by changes in blood flow parameters (rheology), with soluble agonists having a secondary role, stabilizing formed aggregates. We find that in response to vascular injury, thrombi initially develop through the progressive stabilization of discoid platelet aggregates. Analysis of blood flow dynamics revealed that discoid platelets preferentially adhere in low-shear zones at the downstream face of forming thrombi, with stabilization of aggregates dependent on the dynamic restructuring of membrane tethers. These findings provide insight into the prothrombotic effects of disturbed blood flow parameters and suggest a fundamental reinterpretation of the mechanisms driving platelet aggregation and thrombus growth.
Journal Article
Impact of occluder device configurations in in-silico left atrial hemodynamics for the analysis of device-related thrombus
Left atrial appendage occlusion devices (LAAO) are a feasible alternative for non-valvular atrial fibrillation (AF) patients at high risk of thromboembolic stroke and contraindication to antithrombotic therapies. However, optimal LAAO device configurations (i.e., size, type, location) remain unstandardized due to the large anatomical variability of the left atrial appendage (LAA) morphology, leading to a 4-6% incidence of device-related thrombus (DRT). In-silico simulations have the potential to assess DRT risk and identify the key factors, such as suboptimal device positioning. This work presents fluid simulation results computed on 20 patient-specific left atrial geometries, analysing different commercially available LAAO occluders, including plug-type and pacifier-type devices. In addition, we explored two distinct device positions: 1) the real post-LAAO intervention configuration derived from follow-up imaging; and 2) one covering the pulmonary ridge if it was not achieved during the implantation (13 out of 20). In total, 33 different configurations were analysed. In-silico indices indicating high risk of DRT (e.g., low blood flow velocities and flow complexity around the device) were combined with particle deposition analysis based on a discrete phase model. The obtained results revealed that covering the pulmonary ridge with the LAAO device may be one of the key factors to prevent DRT, resulting in higher velocities and reduced flow recirculations (e.g., mean velocities of 0.183 ± 0.12 m/s and 0.236 ± 0.16 m/s for uncovered versus covered positions in DRT patients). Moreover, disk-based devices exhibited enhanced adaptability to various LAA morphologies and, generally, demonstrated a lower risk of abnormal events after LAAO implantation.
Journal Article
Death incidents following transcatheter edge-to-edge repair registry
The transcatheter edge-to-edge repair (TEER) technique, facilitated by the MitraClip device, is a minimally invasive intervention designed for high-risk patients with mitral regurgitation (MR). This study conducts a retrospective analysis of death events associated with MitraClip implantation over a ten-year decade, utilizing data from the FDA's Manufacturer and User Facility Device Experience (MAUDE) database to evaluate trends in safety outcomes. A comprehensive search of the publicly accessible MAUDE database was conducted to retrieve reports of deaths and injuries related to MitraClip implantation from October 2013 to September 2023. Duplicate reports and records from unrelated sources were excluded. The Cochran-Armitage test was performed to evaluate trends in the proportion of fatal events over time. During the 10-year period following FDA approval, the MAUDE database recorded a total of 927 death reports and 9,211 injury reports associated with MitraClip. After excluding duplicates and irrelevant reports, 592 death cases were analyzed. The most commonly reported complications were MR (26.69%), tissue damage (24.16%), and hypotension (22.13%). The most frequent device-related issues were incomplete coaptation (14.70%), difficulty removing the divice (6.42%), and failure to adhere or bond/positioning failure(4.90%). Notably, 76.94% of deaths occurred within one year of implantation. The proportion of fatal events demonstrated a gradual decline, from 15.9% in 2014-2015 to 3.5% in 2020-2021 (p < 0.0001). This analysis of the MAUDE database indicates a gradual decline in the proportion of fatal events associated with MitraClip implantation, which may be attributed to growing operator experience and advancements in device design. Nonetheless, persistent focus is required on managing complications and addressing potential risks to further enhance device performance and optimize its clinical utility.
Journal Article
Reduced Heating Wireless Energy Transmission System for Powering Implanted Circulatory Assist Devices: Benchtop and In-Vivo Studies
This study aimed to develop a novel Transdermal Energy Transmission System (TETS) device that addresses the driveline complications faced by patients with advanced heart failure (HF). Our TETS device utilizes a two-channel configuration with a very-low duty cycle and a pulsed RF power transmission technique, along with elliptically shaped flexible coil inductive coupling elements. We integrated a battery charging controller module into the TETS, enabling it to recharge an implanted Lithium-Ion (Li-Ion) battery that powers low-power-rated Circulatory Assist Devices, or left ventricular assist devices (LVADs). Benchtop measurements demonstrated that the TETS delivered energy from the implanted coils to the battery charging module, at a charging rate of up to 2900 J/h, presented an average temperature increase (ΔT) of 3 °C. We conducted in vivo measurements using four porcine models followed by histopathological analysis of the skin tissue in the implanted coils areas. The thermal profile analysis from the in vivo measurements and the calculated charging rates from the current and voltage waveforms, in porcine models, indicated that the charging rate and temperature varied for each model. The maximum energy charging rate observed was 2200 J/h, with an average ΔT of 3 °C. The exposed skin tissue histopathological analysis results showed no evidence of tissue thermal damage in the in vivo measurements. These results demonstrate the feasibility of our developed TETS device for wireless driving implanted low-power-rated LVADs and Li-Ion charging.
Journal Article
Health-related quality of life in a large cohort of patients with cardiac implantable electronic devices A registry-based study
The association of cardiac implantable electronic devices (CIED), namely pacemaker (PM), implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy with (CRT-D) or without defibrillator (CRT-P) with health-related quality of life (HRQoL) is lacking.
Data from the Swedish Pacemaker and ICD Registry collected from January 2019 to February 2022 was used to analyze the responses to the European Quality of Life-5 Dimension questionnaire (EQ-5D) before and after one year of the CIED implant. Descriptive analysis was performed using Pearson's chi-square test, the analysis of variance ANOVA, the Kruskal-Wallis test and Wilcoxon signed-rank test when appropriate. A multivariable regression analysis was used to compare the EQ-5D index and EQ-VAS variation after 1 year. Of 1,479 who completed the EQ-5D, 80% had a PM, 10% an ICD, 5% a CRT-P and 6% a CRT-D. The median age was 77 years with females constituting 38% of the PM group and 17% of the ICD group. The EQ-VAS and the EQ-5D index significantly increased after one year from the PM and CRT-P implant (EQ-VAS +2.8, standard deviations (SD) 23 and +5.8, SD 24.9; EQ-5D index +0.019, SD 0.114 and +0.051, SD 0.125) while only the EQ-5D index increased after one year from the ICD implant (+0.002, SD 0.104). After adjusting for age, sex and HRQoL at baseline, the presence of defibrillator was associated with lower EQ-VAS (ICD EQ-VAS variation: -3.4, 95% confidence intervals (CI) -6.7; -0.1 and CRT-D EQ-VAS variation -4.8, 95% CI -8.8;-0.7) and EQ-5D index (ICD EQ-5D index variation: -0.018, 95% CI -0.035; -0.0003 and CRT-D EQ-5D index variation -0.025 95% CI 0.046;0.004) after one year compared to PM.
These findings, showing the HRQoL associated with CIED, are important to support physicians' and pacemaker nurses' care after device implantation by embracing the patients' perspectives.
Journal Article
Clinical practice of continuous rhythm monitoring after embolic stroke of undetermined source
Embolic stroke of undetermined source (ESUS) accounts for up to 20% of ischemic strokes annually. Undetected atrial fibrillation (AF) is one important potential underlying cause. For AF, oral anticoagulation has evolved as the most preferable means of secondary stroke prevention. To detect unrecognized paroxysmal AF, long-term ECG monitoring is required, and implantable cardiac monitors (ICM) appear most suitable. Yet, ICMs are particularly costly, implantation is invasive, and remote monitoring places a personnel burden on health care providers. Here, we use data from a large cohort of ESUS patients to systematically analyze the effort of ICM remote monitoring for AF diagnosis and the strain on health care providers.
From a prospective, single-center, observational ESUS registry, we analyzed all ICM-equipped patients post-ESUS (n = 172) between January 1st, 2018, and December 31st, 2019. Through January 2nd, 2023, 48 patients (27.9%) were diagnosed with AF by ICM remote monitoring. During follow-up, a total of 29,180 remote monitoring episodes were transmitted, of which 17,742 were alarms for AF. A systematic estimation of workload revealed that on average, 20.3 trained physician workhours are required to diagnose one patient with AF.
ICM remote monitoring is useful to diagnose AF in cohort of post-ESUS patients. However, the number of ICM alarms is high, even in a cohort at known high risk of AF and in whom AF detection is therapeutically consequential. Improved automated event classification, clear recommendations for ICM interrogation after AF diagnosis, and a careful patient selection for ICM monitoring are warranted.
Journal Article
Infections of cardiac implantable electrical devices
Cardiovascular implantable electronic devices (CIEDs) are susceptible to infections, occurring at a rate of approximately 1 in the first year. These infections can involve the pacemaker pocket, generator, leads, or a combination of these components. Common signs of pocket infections include pain, swelling, discharge, erosion, and fever. The most common causes of CIED infections are coagulase-negative staphylococci and Staphylococcus aureus. Prompt assessment by a cardiac electrophysiologist and an infectious disease specialist is necessary, and blood cultures should be obtained before starting antibiotics. Transesophageal echocardiography is recommended for patients with positive blood cultures or clinical features of infective endocarditis. Treatment involves complete device removal and antibiotic therapy, with the duration of antimicrobial therapy depending on the type of infection. Reimplantation should occur no sooner than 72 hours after device removal and with negative blood cultures. Immediate device removal is indicated for patients with hemodynamic instability, advancing chest wall infection, positive blood cultures, or echocardiographic evidence of CIED-associated endocarditis.
Journal Article