Replacement Devices Research Articles

Parameter Analysis of Resilient Precast Concrete Beam–Column Joints

Conventional precast structures often face the challenge of post-earthquake repair, especially at beam–column joints. A new type of precast concrete beam–column joint with a replaceable energy dissipation device consisting of cross-shaped and H-shaped steel was proposed in this paper, which was characterized by the use of replaceable energy-dissipating devices to improve the seismic capacity. Based on the previous test results of the group, this paper used ABAQUS to investigate how factors like the thickness of the H-shaped steel webs and the size and number of openings affected the seismic performance of precast concrete beam–column joints with replaceable energy dissipation devices. The results showed that (1) an increase in the H-shaped steel’s thickness in the REDDC could improve the load-carrying capacity of the node, but the energy dissipation capacity was weakened, and (2) the length and width of the H-shaped steel openings had almost no effect on the ultimate load-carrying capacity within a certain range, but increasing the size of the openings could improve the energy dissipation capacity and reduce the ultimate load-carrying capacity at the same time. Compared with the length of the openings, the width of the openings had a more significant impact on the energy dissipation capacity. (3) The peak load-carrying capacity decreased with an increase in the number of openings in the H-shaped steel.

In Vivo Mouse Abdominal Oxygen Imaging And Assessment of Subcutaneously Implanted Beta Cell Replacement Devices.

Type 1 diabetes (T1D) is an autoimmune disease that leads to the loss of insulin-producing pancreatic beta cells. Beta cell replacement devices or bioartificial pancreas (BAP) have shown promise in curing T1D and providing long-term insulin independence without the need for immunosuppressants. Hypoxia in BAP devices damages cells and imposes limitations on device dimensions. Noninvasive in vivo oxygen imaging assessment of implanted BAP devices will provide the necessary feedback and improve the chances of success. Pulse-mode electron paramagnetic resonance (EPR) oxygen imaging (EPROI) using injectable trityl OX071 as the oxygen-sensitive agent is an excellent technique for obtaining partial oxygen pressure (pO2) maps in vitro and in vivo. In this study, our goal was to optimize in vivo mouse abdominal EPROI and demonstrate proof-of-concept pO2 imaging of subcutaneously implanted BAP devices. All EPROI experiments were performed using a 25 mT EPROI instrument, JIVA-25®. For in vivo EPROI experiments, trityl OX071, a whole-body mouse resonator (∅32mm × 35mm), C57BL6 mice, and the inversion recovery electron spin echo (IRESE) pulse sequence were utilized. We investigated the signal amplitude and pO2 in mouse abdomen region for intravenous (i.v.) and intraperitoneal (i.p.) injection methods with either only a single bolus (B) or bolus plus infusion (BI) for 72.2mM OX071 and the effect of OX071 concentrations from 18 to 72.2 mM for the i.p.-B injection method. We also investigated the impact of animal respiratory rate on mouse abdominal pO2. Finally, we performed proof-of-concept pO2 imaging of two subcutaneously implanted BAP devices, OxySite and TheraCyte. At the end of the four-week study, the TheraCyte devices were extracted and analyzed for fibrosis, vascular differentiation, and immune cell infiltration. We established that mouse abdominal pO2 remains stable irrespective of trityl injection methods, concentrations, imaging time, or animal breathing rate. We demonstrate that the i.p.-B and i.p.-BI methods are suitable for EPROI, and i.p.-B method provides higher signal amplitude compared to i.v.-BIand up to 75min of imaging. An injection with a reduced trityl concentration and higher volume provides higher signal amplitude for i.p.-B method at the beginning. We also highlight the advantage of milder anesthesia for consistent, reliable mouse pO2 imaging. Finally, we demonstrate that EPROI could provide longitudinal noninvasive oxygen assessment of subcutaneously implanted BAP devices in vivo. In vivo EPROI is a reliable technique for mouse abdominal oxygen imaging and longitudinal assessment of subcutaneously implanted BAP devices noninvasively. This work reports abdominal oxygen imaging in the mouse model and demonstrates its application for the assessment of BAP devices. Even though the application focus of this work was on cell therapy, the techniques developed will have a much broader use in the biomedical field.

Seismic performance of novel high-strength steel external assembled 3U energy dissipator

The development of easily implemented, cost-efficient, and replaceable energy dissipation devices is increasingly emphasized to improve bridge resilience. This study introduces a novel external assembled 3U energy dissipator (EA3UED) made of high-strength steel, designed to enhance the performance of precast segmental concrete bridge piers. The EA3UED, featuring three distinct U-shaped components to provide multi-directional resistance, was evaluated through comprehensive cyclic loading tests on five different specimens to assess their failure modes and practical feasibility. Finite element analysis conducted in Abaqus further assessed parameters such as ultimate bearing capacity, energy dissipation, stiffness, and ductility to identify the optimal geometric configuration. The results indicate that the EA3UED exhibits high energy dissipation, strength, stiffness, and ductility alongside cost-effective benefits. Two primary failure modes were observed: U-shape failure and bolt fractures. The validated finite element models successfully simulated the hysteretic behavior of the EA3UED. And a parametric study based on these models examined the effects of the width of U-shape and the steel grade on the device performance. These improvements demonstrate the EA3UED’s potential for integration in future bridge pier designs, improving their resilience and performance under seismic loads.

Abstract 4118415: Device Dislodgement and Embolization associated with a New Leadless Pacemaker

Background: Leadless pacemakers (LP) avoid the pocket and lead-related complications of transvenous pacing. A potential complication of LPs is dislodgement and/or embolization (D/E) during or after implant. No D/E occurred in the original 725-patient Micra™ VR clinical trial. However, in the 526-patient LEADLESS II-phase 2 trial, the rate of dislodgement for 200 Aveir™ VR LPs was 1.5%. Thus, there appears to be a significant difference in D/E rates between these LPs that have different fixation mechanisms and insertion tools. Aims: We aimed to determine if the Aveir VR LP has continued to exhibit D/E since it was approved by the Food and Drug Administration (FDA) in April 2022. Methods: We queried the FDA's Manufacturers and User Facility Device Experience (MAUDE) database for Aveir D/E that occurred in the U.S. and were reported by the manufacturer from April 2022-December 2023. The number of Aveir VR implants in the U. S. was obtained from the manufacturer's publicly available product performance report. D/E outside the U.S. were excluded. Results: During the 21 months, 55 of 3,139 (1.75%) Aveir VR implants exhibited D/E. More D/E (34;61.8%) occurred during implant, with 18 (52.9%) of these happening after release of the device from the tether mode. Fourteen (41.2%) of the intra-procedural D/E occurred when the device prematurely released from the delivery catheter, and two dislodged during cardiopulmonary resuscitation (CPR). D/E occurred in 21 patients (38.2%) after implant and were signified by loss of pacing or inability to interrogate the device. Four (19%) out of those 21 patients presented with symptomatic bradycardia. The dislodged devices commonly embolized to the pulmonary artery and right atrium/vena cava. LP retrieval was successful in 49 (89%) cases. Thirty-two patients (58.1%) received a new LP, 5 patients were transitioned to a transvenous system, and a replacement device was not specified for 17 (31%) patients. One patient died during implantation due to ventricular fibrillation (VF) not related to D/E. Conclusions: Fixation issues and premature separation of the device from the delivery catheter appear to be responsible for most of these D/E. Studies are needed to determine if impedance or another metric is associated with adequate Aveir fixation. The manufacturer should address the premature separation problem with Aveir. Success of D/E retrieval may be related to tools specific for Aveir. Further studies are needed to compare between the two LPs.

Abstract 4121516: Efficacy of Sentinel Cerebral Embolic Protection Device in Transcatheter Aortic Valve Replacement: A Meta-Analysis of Randomized Controlled Trials and Propensity Score Matched Studies

Background: Transcatheter aortic valve replacement (TAVR) is frequently associated with stroke due to debris embolization. Although the risk of stroke with the newer-generation devices is lower, stroke still represents a significant cause of mortality and morbidity after TAVR. The Sentinel cerebral embolic protection (CEP) device (Boston Scientific) is a dual embolic filter device designed to capture debris dislodged during TAVR. The current literature concerning the efficacy of Sentinel CEP in the reduction of stroke in patients undergoing TAVR is limited and inconsistent. Aim: This meta-analysis aimed to compare clinical outcomes with Sentinel CEP device in patients undergoing TAVR. Methods: A comprehensive systematic literature search was performed on PubMed, Embase, Cochrane Library and Clinicaltrial.gov from inception until 1st May 2024 to retrieve randomized controlled trials (RCTs) and propensity-matched studies comparing TAVR with and without the Sentinel CEP device. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using the DerSimonian-Laird random-effects model, with a p-value of <0.05 considered statistically significant. Results: 6 studies with a total of 25,130 patients undergoing TAVR (12608: Sentinel CEP device; 12522: Without Sentinel CEP device) were included in this meta-analysis. The use of the Sentinel CEP device in TAVR was associated with a statistically significant lower risk of acute kidney injury [OR: 0.89; 95% CI: 0.81, 0.97; p=0.01]. The use of Sentinel CEP device in TAVR was associated with a statistically insignificant trend towards reduction in stroke [OR: 0.80; 95% CI: 0.58, 1.10; p=0.18], all-cause mortality [OR: 0.74; 95% CI: 0.51, 1.07; p=0.11], and major vascular complications [OR: 0.74; 95% CI: 0.46, 1.19; p=0.21]. Conclusion: The use of the Sentinel CEP device in patients undergoing TAVR does not lead to a statistically significant reduction in stroke, all-cause mortality, and major vascular complications; however, the risk of acute kidney injury is lower. Large, multicentric RCTs are warranted to corroborate the findings of this meta-analysis.

Abstract 4138788: Outcomes of Percutaneous Coronary Interventions Following Transcatheter Aortic Valve Replacement: Insights from the National Cardiovascular Data Registry (NCDR) CathPCI Registry

Background: Although transcatheter aortic valve replacement (TAVR) devices can impair coronary access, there are limited real-world data on rates of percutaneous coronary intervention (PCI) and PCI outcomes in post-TAVR patients. Research Question: How often do patients who undergo TAVR develop coronary events, and do they have different procedural characteristics or rates of adverse events when undergoing PCI compared to patients without a TAVR? Methods: We used CMS claims data for the Medicare fee-for-service population to evaluate the incidence of PCI after TAVR between 2011-2017. Then, using data from the NCDR CathPCI Registry linked with Medicare claims, we compared procedural characteristics and PCI outcomes between patients with a history of TAVR vs. propensity-matched patients who did not have a history of TAVR. Results: Of the 52,780 Medicare fee-for-service patients who underwent TAVR between 2011-2017, the incidence of acute myocardial infarction (AMI) was 10.6% and of PCI was 5.4% at five years. Among those patients, 5.6% had a PCI in the three months preceding their TAVR. After propensity-score matching, the procedural success rates for PCI were similar between patients with vs. without a history of TAVR. However, in the propensity-matched comparison, PCI in post-TAVR patients required greater fluoroscopic time (21.9 vs 17.7 mins, p<0.001) and was associated with a greater incidence of post-procedural stroke (0.8% vs 0.4%, p=0.02) and bleeding (5.1% vs 2.9%, p < 0.001). At three-year follow-up post-PCI, there were no differences in the rates of AMI between patients with vs. without a history of TAVR (HR: 1.22, 95% C.I.: 0.97, 1.54, p=0.08). However, patients with prior TAVR were more likely to have repeat PCI in the three years following their index procedure (HR: 1.38, 95% C.I.: 1.12, 1.73, p=0.003). Conclusion: Among Medicare fee-for-service patients, one in 20 patients undergoing TAVR subsequently underwent PCI within 5 years. Although the rates of procedural success were similar, patients with a history of TAVR who underwent PCI had longer fluoroscopic times, more frequent in-hospital adverse events, and a higher likelihood of a repeat PCI compared with matched patients without a history of TAVR.

TCT-154 Early Safety and Feasibility Study of a Novel Transcatheter Aortic Valve Replacement Device With Polymer Leaflets in Treating Patients With Severe Calcific Aortic Stenosis: Sekilia Valve

TCT-154 Early Safety and Feasibility Study of a Novel Transcatheter Aortic Valve Replacement Device With Polymer Leaflets in Treating Patients With Severe Calcific Aortic Stenosis: Sekilia Valve

Prostate magnetic resonance imaging (MRI) in patients with hip implants-presetting a protocol using a phantom.

Metal structures are a source of artifacts that significantly complicate the interpretation of magnetic resonance imaging (MRI). The use of prostate MRI as a preliminary test in men with a suspicion on prostate cancer leads to an increased use of the test. The aim of this study was to solve a clinically significant problem: to ensure the reduction of artifacts from metal hip implants during prostate MRI. Another goal was to evaluate the impact of artifact reduction methods on quantitative measurements. The prostate gland (PG) phantom model was a cylinder filled with an aqueous solution of polyvinylpyrrolidone at the concentrations of 40%, 30%, and 20% [central zone (CZ), peripheral zone (PZ), and "lesion", respectively]. Phantom MRI study was conducted on Philips Ingenia 1.5T and Philips Ingenia 3T scanners. For 1.5 T, the reduction in the influence of artifacts inside region of interest (ROI) was observed, expressed in a decrease in the average apparent diffusion coefficient (ADC) (CZ, PZ, "lesion") for the manual artifact reduction (MAR) and ZOOM (title of software artifact reduction) techniques compared to the standard method. For 3T this effect was not detected. The same ADC results were obtained for Standard and MAR techniques, and increased ADC values for ZOOM. Despite the fact that the spread of ADC values on 3.0T scanners was minimal, there was a significant deviation of ADC values from the reference ones (up to 30.4%). Therefore, it is necessary to use a correction coefficient in the ADC calculation for the 3.0 T device. In the presented clinical case, high-quality tomograms were obtained without any artifacts, despite the presence of two hip replacement devices in the scanning area. The accurate prostate MRI in the presence of implants is essential for an accurate diagnosis. This approach allows to reduce artifacts from hip implants, to visualize PG and periprostatic tissue in the best way, and to detect malignant and benign changes.

TMJ Concepts Patient-Fitted TMJ Reconstruction Prosthesis System: Results from an FDA Post-Market Surveillance Prospective Cohort Study

BackgroundCustom-designed and patient-fitted temporomandibular joint replacement devices (TMJR) are employed to manage end-stage TMJ pathology, distorted bony TMJ architecture, or in patients who have undergone multiple prior failed TMJ surgeries. PurposeThis study aimed to measure the frequency of revision or replacement over time, estimate the 1, 2, and 3-year survival rate of implants, and determine what demographic, anatomical, or operative variables may be associated with a device adverse event. Study design, setting, and sampleA prospective cohort study was conducted on consenting adults who could read English, implanted with the TMJ Concepts TMJR prostheses between 2013 and 2015 by private or academic surgeons. Patients under the age of 18 and those who were incapable, unwilling, or unable to complete the perioperative forms were excluded. Outcome variablesThe primary outcome variable was the frequency of adverse events, which is defined as device revision or replacement. The secondary outcome variable was the survival rate for the TMJ Concepts devices. AnalysesDevice survival at 1, 2, and 3 years was estimated using the Kaplan-Meyer methodology. Cox proportional hazards regression was used to analyze the effects of the predictor variables for the device survival rate. A p-value of <0.05 was considered significant. ResultsA total of 738 subjects (1098 joints) were enrolled in the study with 102 (14%) males and 636 (86%) females. The mean age was 45.4 (+ 14.8) years. The median follow-up period was 36.2 months (95% CI: 36.1 – 36.2 months). A total of 187 subjects (25.3%) were lost to follow-up during; the study period. Forty-nine devices (4.46%) were associated with an adverse event at 3 years. The; 3-year device survival was 95.1 % (95% CI: 93.6 – 96.3%). The only significant risk factor for an adverse event was the asymmetry of the mandible (hazard rate ratio = 1.989, p = 0.03). The primary diagnosis was not associated with the time to an adverse event (p-value = 0.8685). Infection (44.7 %, 21 joints) and material sensitivity (12.8 %, 6 joints) were the most common reasons specifically for device removal/replacement in the study cohort. ConclusionsInfection was the primary reason reported for device revision or replacement followed by material sensitivity. In the study cohort, the device survival following implantation of the TMJ Concepts prosthesis was not significantly different than reported by the TMJR stock device.

Efficacy of Sentinel Cerebral Embolic Protection Device in Transcatheter Aortic Valve Replacement: A Meta-Analysis of Randomized Controlled Trials and Propensity Score-Matched Studies.

Transcatheter aortic valve replacement (TAVR) is frequently associated with stroke due to debris embolization. Although the risk of stroke with newer-generation devices is lower, stroke still represents a significant cause of mortality and morbidity post-TAVR. The Sentinel cerebral embolic protection device (CEPD) is a dual-embolic filter device designed to capture debris dislodged during TAVR. A systematic literature search was performed on the major bibliographic databases to retrieve studies that compared TAVR with and without Sentinel CEPD. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the DerSimonian-Laird random-effects model, with a P value of <0.05 considered statistically significant. This meta-analysis included 6 studies with 25,130 patients undergoing TAVR (12,608: Sentinel CEPD; 12,522: without Sentinel CEPD). The use of the Sentinel CEPD in TAVR was associated with a statistically significant lower risk of acute kidney injury (OR: 0.89; 95% CI: 0.81-0.97; P = 0.01]. The use of Sentinel CEPD in TAVR was associated with a statistically insignificant trend toward a reduction in stroke (OR: 0.80; 95% CI: 0.58-1.10; P = 0.18), all-cause mortality (OR: 0.74; 95% CI: 0.51-1.07; P = 0.11), and major vascular complications (OR: 0.74; 95% CI: 0.46-1.19; P = 0.21). The use of Sentinel CEPD in patients undergoing TAVR does not lead to a statistically significant reduction in stroke, all-cause mortality, or major vascular complications; however, the risk of acute kidney injury is lower. Further randomized studies are warranted to confirm these findings.

Effect of bioprosthetic leaflet anisotropy on stent dynamics of Transcatheter Aortic Valve Replacement devices

The assessment of stent fatigue in Transcatheter Aortic Valve Replacement (TAVR) systems is critical for the design of next-generation devices, both in vitro and in vivo. The mechanical properties of the bioprosthetic heart valves (BHVs) have a significant impact on the fatigue life of the metallic stent and thus must be taken into consideration when evaluating new TAVR device designs. This study aims to investigate the relationship between BHV anisotropic behaviour and the asymmetric deflections of the stent frame observed during in vitro testing.An explicit dynamics finite element model of the nitinol stent with attached bioprosthetic valve leaflets was developed to evaluate the deflections of the TAVR device under haemodynamic loading. Our results demonstrate that pericardium behaviour plays a dominant role in determining stent frame deflection. The anisotropic behaviour of the leaflets, resulting from collagen fibre orientation, affects the extent of deflection encountered by each commissure of the frame. This leads to asymmetric variation in frame deflection that can influence the overall fatigue life of the nitinol stent. This study highlights the importance of considering both the flexible nature of the metallic stent as well as the leaflet anisotropic behaviour in the design and fatigue assessment of TAVR systems.

Early Feasibility Study with the SATURN Transapical Mitral Valve Replacement Device

PurposeTo report the outcomes of the early feasibility study of transapical transcatheter mitral valve replacement (TMVR) with the SATURN System (InnovHeart, Milano, Italy) to treat patients with severe functional mitral regurgitation. DescriptionFive high surgical risk patients underwent transapical transcatheter mitral valve replacement with the SATURN System at a single center. One-year follow-up is complete for all patients. EvaluationThe valve was implanted successfully in all patients without any major adverse events. All patients were alive at the last follow-up. Kansas City Cardiomyopathy Questionnaire improved from a median of 63.5 (interquartile range, 19.6) at baseline to 99.0 (interquartile range, 21.6) at 1 year. Echocardiographic follow-up demonstrates stable valve function, no transvalvular or paravalvular mitral regurgitation, and absence of left ventricular outflow tract obstruction. ConclusionsAt 1 year after transapical SATURN transcatheter mitral valve replacement, all patients are alive with quality of life improvement and favorable device hemodynamics. These initial results are promising and larger scale studies with continued follow-up are required to further elucidate the efficacy and safety of this novel technology.

Removals and Revisions of Cervical Total Disc Replacement Devices in a Consecutive Series of 1626 Patients Beginning With the First Case Experience in 2003.

Retrospective cohort study. The purpose of this study was to investigate the rate of cervical total disc replacement (TDR) device removal or revision. Cervical TDR has gained acceptance as an alternative to anterior cervical discectomy and fusion in appropriately selected patients. There have been concerns over device safety, one measure of which is subsequent surgery related to device problems. A consecutive series of 1626 patients undergoing cervical TDR from 2003 to June 2021 were included, consisting of TDRs up to 3 levels and hybrids (TDR and fusion). TDR removal or revision surgeries and reasons for these surgeries, procedures performed, and duration from index procedure were recorded. Data were analyzed to determine the removal/revision rate and factors possibly related to these events. There were 24 removals/revisions (1.48%) in the 1626 patients. Removal was performed in 23 cases (1.41%) and revision in 1 (0.06%). Among removal cases, anterior cervical discectomy and fusion was performed in 18 and TDR was replaced with another TDR in 5. Removals with fusion included 5 cases of osteolysis with/without Cutibacterium acnes , 4 device displacement/migration, 4 posterior spinal pathology, and one for each of the following: metal allergy, approach-related complications, malpositioning, subsidence, and hypermobility. The revision involved TDR repositioning 3 days after index surgery. There were 66 patients for whom a minimum of 10-year follow-up was confirmed, and none had removal/revision surgery 10 or more years after index surgery. There was no relationship between the occurrence of removal/revision and age, sex, body mass index, or physician experience (learning curve). The removal/revision rate was significantly higher in FDA trials versus postapproval (4.1% vs . 1.3%, P < 0.05). In this large consecutive series of patients, 1.48% of cervical TDRs were removed/revised. The low rate of removals/revisions over a long period of time provides support for the devices' safety. Level IV.

Percutaneous balloon mitral valvuloplasty with shockwave lithotripsy for the treatment of calcific mitral valve stenosis.

Calcific mitral stenosis (calcific MS) presents a challenge for surgical treatment and is a contraindication for most contemporary transcatheter mitral valve replacement devices (TMVR), rendering patients with very limited therapeutic options. This study aims to assess the clinical and hemodynamic follow-up after mitral valve lithotripsy (MVL). All consecutive patients who underwent MVL to treat symptomatic calcific MS at St Michael's Hospital, Toronto, Canada, were included. Patients were deemed unsuitable for mitral surgery or TMVR after heart team assessment. Patients with rheumatic MS or ≥moderate mitral regurgitation (MR) were excluded. The primary endpoint was a reduction in the invasive mitral gradient by ≥50% without significant (≥moderate) MR. Fifteen patients underwent MVL between 2021 and 2023 with a mean age of 74 ± 9 years; 53% were female, with a mean STS score of 10% ± 0.1%. Following MVL, there was a reduction in the invasively measured mean trans-mitral gradient compared to baseline (14 mmHg vs. 6 mmHg; p < 0.05). The primary endpoint was achieved in 8 patients (53%) with no major procedural complications. At follow-up (median 90 days, IQR 58-115 days), 14 (93%) patients reported improved symptoms from New York Heart Association (NYHA) Class III-IV to NYHA Class I-II (p < 0.01) with stable echo-derived mean gradient (7.7 mmHg ± 2 mmHg vs. 8.4 mmHg ± 2.9 mmHg (p = 0.7). In selected patients with symptomatic inoperable calcific MS, MVL was safe and associated with significant short-term clinical and hemodynamic improvement. MVL may represent a new compassionate therapy for this challenging cohort. Further studies are needed to determine the long-term outcomes and help define the role of IVL technology in treating calcific valvular conditions.

Comparison of four in vitro test methods to assess nucleus pulposus replacement device expulsion risk.

Nucleus replacement devices (NRDs) are not routinely used in clinic, predominantly due to the risk of device expulsion. Rigorous in vitro testing may enable failure mechanisms to be identified prior to clinical trials; however, current testing standards do not specify a particular expulsion test. Multiple methods have therefore been developed, complicating comparisons between NRD designs. Thus, this study assessed the effectiveness of four previously reported expulsion testing protocols; hula-hoop (Protocol 1), adapted hula-hoop (Protocol 2), eccentric cycling (Protocol 3), and ramp to failure (Protocol 4), applied to two NRDs, one preformed and one in situ curing. Nucleus material was removed from 40 bovine tail intervertebral disks. A NRD was inserted posteriorly into each cavity and the disks were subjected to one of four expulsion protocols. NRD response was dependent on both the NRD design and the loading protocol. Protocol 1 resulted in higher migration and earlier failure rates compared to Protocol 2 in both NRDs. The preformed NRD was more likely to migrate when protocols incorporated rotation. The NRDs had equal migration (60%) and expulsion (60%) rates when using unilateral bending and ramp testing. Combining the results of multiple tests revealed complimentary information regarding the NRD response. Adapted hula-hoop (Protocol 2) and ramp to failure (Protocol 4), combined with fluoroscopic analysis, revealed complimentary insights regarding migration and failure risk. Therefore, when adopting the surgical approach and animal model used in this study, it is recommended that NRD performance be assessed using both a cyclic and ramp loading protocol.

Fish swim bladders as valve leaflets enhance the durability of transcatheter aortic valve replacement devices

Transcatheter aortic valve replacement (TAVR) has emerged as an effective therapy for inoperable patients with severe aortic stenosis (AS). However, calcification-induced limited durability restricts its application. Fish swim bladders (FSB), which are resistant to calcific degeneration, offer a viable solution to this challenge. In this study, we developed a new TAVR device using FSB as the valve leaflet. Furthermore, the in vitro durability, in vivo performance, and size selection of this TAVR device were assessed by an experimental study and finite element analysis. A self-expandable TAVR device was fabricated by suturing the FSB films into a 23 mm nitinol alloy frame. Further, hemodynamic performance, such as effective orifice area, transvalvular pressure difference and regurgitant fraction, the durability was tested by the pulsatile flow test and accelerated fatigue test, according to the ISO 5840-3. The effect of release size on hydrodynamic performance was also investigated. Finally, the in vivo performance of the TAVR device were examined using a porcine implantation model. The results showed that the strength of the FSB films satisfied the requirements for valve leaflets. The hemodynamic performance of the FSB TAVR device met the requirements of ISO 5840-3 standards. After 400 million cycles, the FSB showed no fiber loss, torn, perforation, or other valve failure phenomena. In porcine models, the devices were well-positioned, functioned well with no stenosis immediately after the operation. Collectively, we successfully developed a TAVR device with FSB as valve leaflets that exhibited good fatigue resistance. Statement of significanceThe source of material for the leaflets of commercialized biological heart valves (BHVs) is mainly bovine pericardium, but this material suffers the following problems: large and uneven thickness of the material, the presence of α-Gal and Neu5Gc antigens, and the susceptibility to structural valve degradation (SVD). New material for BHVs leaflets is rarely reported. In this study, we prepared a transcatheter aortic valve (TAV) and performed long-term in vitro and short-term in vivo studies using fish swim bladder (FSB) as the leaflets. The study confirmed that FSB TAV device can complete 400 million fatigue tests and maintain the good morphology of the leaflets, and that it still maintains good functionality after a certain amount of compression, indicating that FSB is a promising material for leaflets.

Cerebral Embolic Protection Devices for Transcatheter Aortic Valve Replacement: Review of the Literature and Future Perspectives.

Transcatheter aortic valve replacement (TAVR) has been a revolutionary therapy in the treatment of aortic valve stenosis. The risk of stroke associated with TAVR has decreased significantly since its introduction; however, it remains a devastating complication when it does occur. Many of the strokes associated with TAVR occur peri-procedurally and are thought to be due to embolic debris entering the cerebrovascular circulation. A number of different cerebral embolic protection devices (CEPD) have been developed and are in various stages of testing and use. The results from clinical trials evaluating the role for CEPD to reduce the risk of stroke have been mixed. As a result, their uptake has been very heterogeneous. This review provides a summary of the diverse CEPD devices available for use and outlines the clinical evidence available to date.

The Effect of Aortic Angulation on Clinical Outcomes of Patients Undergoing Transcatheter Aortic Valve Replacement.

The aim of this study was to assess the impact of aortic angulation (AA) on periprocedural and in-hospital complications as well as mortality of patients undergoing Evolut™ R valve implantation. A retrospective study was conducted on 264 patients who underwent transfemoral-approach transcatheter aortic valve replacement with self-expandable valve at our hospital between August 2015 and August 2022. These patients underwent multislice computer tomography scans to evaluate AA. Transcatheter aortic valve replacement endpoints, device success, and clinical events were assessed according to the definitions provided by the Valve Academic Research Consortium-3. Cumulative events included paravalvular leak, permanent pacemaker implantation, new-onset stroke, and in-hospital mortality. Patients were divided into two groups, AA ≤ 48° and AA > 48°, based on the mean AA measurement (48.3±8.8) on multislice computer tomography. Multivariable logistic regression analysis was performed to identify predictors of cumulative events, utilizing variables with a P-value < 0.2 obtained from univariable logistic regression analysis, including AA, age, hypertension, chronic renal failure, and heart failure. AA (odds ratio [OR]: 1.73, 95% confidence interval [CI]: 0.89-3.38, P=0.104), age (OR: 1.04, 95% CI: 0.99-1.10, P=0.099), hypertension (OR: 1.66, 95% CI: 0.82-3.33, P=0.155), chronic renal failure (OR: 1.82, 95% CI: 0.92-3.61, P=0.084), and heart failure (OR: 0.57, 95% CI: 0.27-1.21, P=0.145) were not found to be significantly associated with cumulative events in the multivariable logistic regression analysis. This study demonstrated that increased AA does not have a significant impact on intraprocedural and periprocedural complications of patients with new generation self-expandable valves implanted.

Effect of temperature and time on the synthesis of calcium phosphate obtained by microwave hydrothermal method

Bioceramics are materials used in biomedical devices for bone replacement, and calcium phosphate derivatives are widely used in cases of bone defect repair. The aim was to evaluate the influence of temperature and time on the synthesis of calcium phosphate obtained by the microwave hydrothermal method on its structural and morphological characteristics with a view to application as a bone graft. The calcium phosphate powders (calcium octophosphate, hydroxyapatite and calcium triphosphate) were produced using the microwave hydrothermal method. To obtain the calcium phosphate powders, aqueous solutions of Ca (OH)2 and H3 PO4 were used and subjected to the microwave hydrothermal method at temperatures of 110°C and 130°C for 30 and 60 minutes, then calcined at 700°C for 1 hour and characterized using XRD, FTIR, SEM, particle size distribution, apparent density, and apparent porosity. The results obtained by the techniques confirm crystalline and morphological modifications, and homogeneous distribution of the particles, and the phases of interest, octophosphate, hydroxyapatite and calcium β-triphosphate, were identified. The formation of the β-TCP phase was predominant in the samples in which the microwave hydrothermal synthesis was carried out over a longer time and at a higher temperature. It was found that the proposed synthesis method was effective in terms of time/temperature, offering advantages over conventional techniques, such as improving the primary characteristics for choosing a biomaterial to be used in cases of bone regeneration.

Lumbar Total Disk Replacement Device Removals and Revisions Performed During a 20-Year Experience with 2141 Patients.

This was a retrospective study with prospective patient contact attempted to collect current data. The purpose was to investigate the incidence and reasons for lumbar total disk replacement (TDR) removal or revision. A concern regarding lumbar TDR was safety, particularly the need for device removal or revision. This may be particularly important considering removal/revision requires repeat anterior exposure with an increased risk of vascular injury. Data were collected for a series of 2141 lumbar TDR patients, beginning with the first case experience in 2000. The mean follow-up was 78.6 months. For each case of device removal/revision, the reason, duration from index surgery, and procedure performed were recorded. Of 2141 patients, 27 (1.26%) underwent TDR removal or revision. Device removal was performed in 24 patients (1.12%), while three patients underwent revision (0.14%). Of the 24 removals, 12 were due to migration and/or loosening, three developed problems post-trauma, two developed lymphocytic reaction to device materials, two had ongoing pain, and there was one case of each: TDR was too large, vertebral body fracture (osteoporosis), lytic lesion, device subsidence and facet arthrosis, and infection seeded from a chest infection 146 months post-TDR. The three revisions were for Core repositioning (technique error), device repositioning after displacement, and core replacement due to wear/failure. With respect to timing, 37.0% of removals/revisions occurred within one-month postimplantation. Of note, 40.7% of removals/revisions occurred in the first 25 TDR cases performed by individual surgeons. There was one significant vascular complication occurring in a patient whose TDR was removed due to trauma. This was also the only patient among 258 with ≥15-year follow-up who underwent removal/revision. In this large consecutive series, 1.26% of TDRs were removed/revised. The low rate over a 20 year period supports the safety of these devices.