Impact of the COVID-19 Pandemic on Global TAVR Activity: The COVID-TAVI Study.

BACKGROUND: The COVID-19 pandemic adversely affected health care systems. Patients in need of transcatheter aortic valve replacement (TAVR) are especially susceptible to treatment delays. OBJECTIVES: This study sought to evaluate the impact of the COVID-19 pandemic on global TAVR activity. METHODS: This international registry reported monthly TAVR case volume in participating institutions prior to and during the COVID-19 pandemic (January 2018 to December 2021). Hospital-level information on public vs private, urban vs rural, and TAVR volume was collected, as was country-level information on socioeconomic status, COVID-19 incidence, and governmental public health responses. RESULTS: We included 130 centers from 61 countries, including 65,980 TAVR procedures. The first and second pandemic waves were associated with a significant reduction of 15% (P < 0.001) and 7% (P < 0.001) in monthly TAVR case volume, respectively, compared with the prepandemic period. The third pandemic wave was not associated with reduced TAVR activity. A greater reduction in TAVR activity was observed in Africa (-52%; P = 0.001), Central-South America (-33%; P < 0.001), and Asia (-29%; P < 0.001). Private hospitals (P = 0.005), urban areas (P = 0.011), low-volume centers (P = 0.002), countries with lower development (P < 0.001) and economic status (P < 0.001), higher COVID-19 incidence (P < 0.001), and more stringent public health restrictions (P < 0.001) experienced a greater reduction in TAVR activity. CONCLUSIONS: TAVR procedural volume declined substantially during the first and second waves of the COVID-19 pandemic, especially in Africa, Central-South America, and Asia. National socioeconomic status, COVID-19 incidence, and public health responses were associated with treatment delays. This information should inform public health policy in case of future global health crises.

Dynamic white lighting to aid sleep and vision for persons living with dementia using off-the-shelf LED strips.

Alzheimer disease and related dementias affect 15-20% of elderly people, and 60-70% of these suffer from sleep disturbances. Studies suggest that lighting can improve sleep. The key challenge is how to deliver light effectively. We have designed a lighting system that adjusts spectrum and irradiance on a 24-hour timetable to provide spatially uniform, shadow-free white light with CRI>85 and up to 1000 Lux for day vision and amber light for night vision. To aid sleep, melanopic illuminance varies over 3 orders of magnitude to enable strong suppression of melatonin in the morning/early afternoon, moderate suppression in the evening, and no suppression at night.

Real-time phase-retrieval and wavefront sensing enabled by an artificial neural network.

In this manuscript we demonstrate a method to reconstruct the wavefront of focused beams from a measured diffraction pattern behind a diffracting mask in real-time. The phase problem is solved by means of a neural network, which is trained with simulated data and verified with experimental data. The neural network allows live reconstructions within a few milliseconds, which previously with iterative phase retrieval took several seconds, thus allowing the adjustment of complex systems and correction by adaptive optics in real time. The neural network additionally outperforms iterative phase retrieval with high noise diffraction patterns.

Atrial fibrillation in acute coronary syndrome: patient characteristics and appropriate utilisation of anti-thrombotic therapy in New Zealand (ANZACS-QI 39).

BACKGROUND: Concomitant atrial fibrillation (AF) and acute coronary syndrome (ACS) present the difficult therapeutic dilemma of balancing bleeding, cardio-embolic and coronary thrombotic risks with appropriate combinations of antithrombotic medications. We aim to evaluate current New Zealand practice by identifying the incidence of AF in ACS; describe the population characteristics; and assess our antithrombotic management. METHODS: Consecutive patients ≥18y presenting with ACS who had coronary angiography (2017-2018) were identified from the All New Zealand ACS Quality Improvement (ANZACS-QI) registry. The cohort was divided into three groups: 1) patients with pre-existing AF; 2) new-onset AF; and 3) no AF. Antithrombotic regimens included dual antiplatelet therapy (DAPT), dual antithrombotic therapy (DAT-single antiplatelet plus an oral anticoagulant (OAC)) and triple antithrombotic therapy (TAT). RESULTS: There were 9,489 patients, 9.6% with pre-existing AF, 4.4% new AF and 86% without AF. Both AF groups were older (median 74 vs 71 vs 65y, p=0.001), had poorer renal function, were more likely to present with heart failure (16% vs 19% vs 8%, p=0.001) and have left ventricular ejection fraction <40% (22% vs 28% vs 13%, p<0.001). They received less percutaneous coronary intervention (PCI) (53% vs 59% vs 70%, p=0.001). In the cohort, 25 different combinations of antithrombotic agents were utilised. Ninety-six percent of patients with any AF had a CHA2DS2VASC stroke risk score of ≥2, of whom 48% did not receive OAC. Twenty-four percent received TAT and 19% DAT. OAC use increased slightly with increasing stroke risk but were independent of CRUSADE bleeding risk. Of patients with AF treated with PCI, 53% received DAPT, 11% DAT and 35% TAT. 51% of those at high stroke risk were discharged on DAPT only. In contrast, 19% at low stroke risk received TAT. CONCLUSION: In New Zealand, one in seven patients presenting with ACS have AF, a third being new-onset AF. Antithrombotic management is inconsistent, with underutilisation of anticoagulants, particularly the DAT regimen, and is inadequately informed by stroke and bleeding risk scores.

Attosecond pulse retrieval from noisy streaking traces with conditional variational generative network.

Accurate characterization of an attosecond pulse from streaking trace is an indispensable step in studying the ultrafast electron dynamics on the attosecond scale. Conventional attosecond pulse retrieval methods face two major challenges: the ability to incorporate a complete physics model of the streaking process, and the ability to model the uncertainty of pulse reconstruction in the presence of noise. Here we propose a pulse retrieval method based on conditional variational generative network (CVGN) that can address both demands. Instead of learning the inverse mapping from a streaking trace to a pulse profile, the CVGN models the distribution of the pulse profile conditioned on a given streaking trace measurement, and is thus capable of assessing the uncertainty of the retrieved pulses. This capability is highly desirable for low-photon level measurement, which is typical in attosecond streaking experiments in the water window X-ray range. In addition, the proposed scheme incorporates a refined physics model that considers the Coulomb-laser coupling and photoelectron angular distribution in streaking trace generation. CVGN pulse retrievals under various simulated noise levels and experimental measurement have been demonstrated. The results showed high pulse reconstruction consistency for streaking traces when peak signal-to-noise ratio (SNR) exceeds 6, which could serve as a reference for future learning-based attosecond pulse retrieval.

Double optical gating for generating high flux isolated attosecond pulses in the soft X-ray regime.

Double optical gating (DOG) technique was implemented with a two-cycle, 1.7 µm driving field to generate isolated attosecond pulses in the 100-250 eV spectrum range. The strong ellipticity dependency of the high harmonics from the 1.7 µm driving field makes polarization based gating method very efficient. When a second harmonic (SH) field is introduced, complete gating can be achieved with less ionization from the leading edge of the driving field, which yields supercontinua with a pulse energy of 0.3 nJ. We perform an attosecond streaking measurement to confirm the generation of isolated attosecond pulses.

Attosecond streaking phase retrieval with neural network.

A new method for retrieving the spectral phase of isolated attosecond X-ray pulses from streaking traces is explored. The neural network method shows the potential for nearly instantaneous attosecond streaking phase retrieval, without use of the central momentum approximation. A neural network is trained with computer generated data that contain statistical noise and shown to correctly retrieve the phase of both computer generated and experimental attosecond streaking traces.

MEH-PPV photophysics: insights from the influence of a nearby 2D quencher.

The effect of 2D quenching on single chain photophysics was investigated by spin coating 13 nm thick films of polystyrene lightly doped with MEH-PPV onto CVD grown graphene and observing the changes in several photoluminescent (PL) observables. With 99% of the PL quenched, we found a 60% drop in the PL lifetime, along with a significant blue-shift of the PL emission due to the preferential quenching of emission at longer wavelengths. During photo-bleaching, the blue spectral shift observed for isolated polymers was eliminated in the presence of the quencher up until 70% of the polymer was photo-bleached. Results were interpreted using a static disorder induced conjugation length distribution model. The quencher, by opening up a new non-radiative decay channel, ensures that excitons do not have sufficient time to migrate to nearby lower energy chromophores. The reduction of energy transfer into the lowest-energy chromophores thus reduces their rate of photo-bleaching. Finally, the difference between the quenched and non-quenched spectra allows the rate of energy transfer along the polymer backbone to be estimated at ∼2 ns-1.

Large Left Ventricular Outflow Tract Pseudoaneurysm Closed Percutaneously From a Novel Apical Approach.

An incidental finding of a large left ventricular outflow tract pseudoaneurysm in a 74-year-old man, with high surgical risk, was managed with a novel, fully percutaneous, left ventricular apical approach. The pseudoaneurysm defect and the apical puncture site were successfully closed with Amplatzer septal occluders with successful positioning, as demonstrated on cardiac computed tomography at 6 weeks follow-up. (Level of Difficulty: Intermediate.).

Valve-in-Valve in a Flail Bioprosthetic Mitral Valve With Endocarditis Using a Novel Embolic Protection Device.

A 79-year-old woman presented in cardiogenic shock with a flail bioprosthetic mitral valve leaflet and Staphylococcus aureus endocarditis. In the absence of other viable options, transfemoral valve-in-valve transcatheter mitral valve replacement was performed with a novel embolic protection device, resulting in trace mitral regurgitation and no neurologic complications. (Level of Difficulty: Advanced.).

Meta-analysis of the Impact of Avoiding Balloon Predilation in Transcatheter Aortic Valve Implantation.

Balloon predilation (BPD) has been an integral part of transcatheter aortic valve implantation (TAVI) since inception. We sought to investigate the effect of avoiding BPD on outcomes of TAVI across different valve types. Articles were included if outcomes of TAVI without BPD were reported. Pooled meta-analysis used a random effects model and reported odds ratios (ORs). Twenty-one studies with 10,752 patients were pooled for analysis. Age and gender were well matched between NoBPD and BPD groups. There was no difference in mortality, stroke, bleeding, and acute kidney injury. NoBPD showed lower pacemaker rates (OR 0.84, 95% confidence interval [CI] 0.72 to 0.97), vascular complications (OR 0.77, 95% CI 0.62 to 0.95), and early safety at 30 days (OR 0.81, 95% CI 0.66 to 0.99). For balloon-expandable valves, lower rates of aortic regurgitation (OR 0.73, 95% CI 0.53 to 0.99) and early safety (OR 0.68, 95% CI 0.55 to 0.85) were seen. Self-expanding valves showed lower pacemaker (OR 0.80, 95% CI 0.66 to 0.97) and vascular complications (OR 0.70, 95% CI 0.50 to 0.99), with a trend toward higher postdilation (OR 1.51, 95% CI 0.85 to 2.67). TAVI without BPD is safe and effective. NoBPD is associated with fewer vascular complications, less aortic regurgitation, and fewer pacemaker requirements and composite early safety end points.

Comparative analysis of cerebrovascular events in transcatheter and surgical aortic valve replacement: a systematic review and meta-analysis of randomised trials.

AIMS: Transcatheter aortic valve replacement (TAVR) has become the procedure of choice for inoperable patients and a safe alternative to surgical aortic valve replacement (SAVR) among moderate-risk patients. We used meta-analysis to compare the incidence of cerebrovascular events amongst patients undergoing TAVR and SAVR in randomised controlled trials (RCT). METHODS AND RESULTS: Our search revealed five RCT published between 2011 and 2017 with a total of 5,414 patients. Data were summarised as Mantel-Haenszel relative risk (RR) and 95% confidence intervals (CI). The risk of major stroke (RR 0.89, 95% CI: 0.53-1.51), all strokes (RR 0.85, 95% CI: 0.59-1.22) and all cerebrovascular events (RR 0.94, 95% CI: 0.75-1.17) was comparable between patients undergoing TAVR and SAVR at 30 days of follow-up. The risk of all strokes (RR 0.92, 95% CI: 0.69-1.22), major stroke (RR 0.92, 95% CI: 0.62-1.37) and all cerebrovascular events (RR 1.03, 95% CI: 0.79-1.33) was comparable between TAVR and SAVR at one year of follow-up. The incidence of major stroke (RR 1.02, 95% CI: 0.64-1.61), all strokes (RR 1.12, 95% CI: 0.78-1.62) and all cerebrovascular events (RR 1.23, 95% CI: 0.91-1.66) was comparable between TAVR and SAVR between 30 days and one year of follow-up. CONCLUSIONS: In our meta-analysis of RCT comparing TAVR and SAVR, we showed comparable risk of major stroke, all stroke and all cerebrovascular events.

Sex-Specific Outcomes of Transcatheter Aortic Valve Replacement With the SAPIEN 3 Valve: Insights From the PARTNER II S3 High-Risk and Intermediate-Risk Cohorts.

OBJECTIVES: The purpose of this study was to identify sex-specific outcomes of intermediate risk patients undergoing transcatheter aortic valve replacement with the SAPIEN 3 valve. BACKGROUND: A survival difference has been observed in women as compared with men in inoperable and high-risk patients receiving early-generation balloon-expandable valves for transcatheter aortic valve replacement (TAVR). Whether a sex-specific outcome difference persists with newer-generation valves and in lower-risk patients is unknown. METHODS: The PARTNER (Placement of Aortic Transcatheter Valves) II S3 trial included high-risk (HR) (Society of Thoracic Surgeons risk score >8% or heart team determination) and intermediate-risk (IR) (Society of Thoracic Surgeons risk score 4% to 8% or heart team determination) patients with severe symptomatic aortic stenosis who were treated with TAVR with the SAPIEN 3 valve. Patient characteristics and clinical outcomes at 30 days and 1 year were compared by sex. RESULTS: Between October 2013 and December 2014, 1,661 patients were enrolled: 583 were HR (338 men, 245 women) and 1,078 were IR (666 men, 412 women). In both cohorts, women were more likely than men to be frail (22% vs. 13%; p < 0.001), but less likely to have comorbid conditions of renal insufficiency, coronary artery disease, atrial fibrillation, or chronic obstructive pulmonary disease. Women were more likely to receive ≤23-mm valves (74.1% vs. 11.1%; p < 0.001) and were less likely to receive 29-mm valves (1.4% vs. 35.1%; p < 0.001). In the combined cohorts, there was no difference in mortality for women compared with men at 30 days (2.0% vs. 1.2%; p = 0.20) or 1 year (9.3% vs. 10.2%; p = 0.59). There were no differences in disabling stroke or any stroke at 30 days or 1 year; however, women had an increased rate of minor stroke at 30 days (2.1% vs. 0.7%; p = 0.01). Female sex was associated with increased major vascular complications (7.9% vs. 4.4%; p = 0.003), but not with moderate or severe paravalvular regurgitation. Notably, similar outcomes regarding sex-specific outcomes were obtained within stratified analyses of the HR and IR cohorts. CONCLUSIONS: The study found no apparent sex-specific differences in survival or stroke in this trial of TAVR. This may reflect the changing demographic of patients enrolled, use of newer-generation valves with more sizes available, and more accurate valve sizing techniques.

Clinical and procedural outcomes with the SAPIEN 3 versus the SAPIEN XT prosthetic valves in transcatheter aortic valve replacement: A systematic review and meta-analysis.

OBJECTIVES: The SAPIEN 3 valve (S3V) was designed to overcome the shortcomings of its predecessor, the SAPIEN XT (SXT) valve. We conducted a meta-analysis to compare their clinical outcomes and procedural characteristics. METHODS: PUBMED, EMBASE, and Cochrane CENTRAL were searched by two independent reviewers. The clinical outcomes of interest were paravalvular leakage (PVL), major vascular complications (MVC), bleeding, acute kidney injury (AKI), device success, need for post dilation all-cause mortality and procedural details. RESULTS: Fifteen observational cohort studies were included in the analysis involving a total of 4,496 patients. Of these, 1,700 were S3V recipients and 2,796 were SXT recipients. The S3V group showed fewer complications compared to the SXT group with respect to PVL (5.58% vs. 19.35%, OR: 0.27, P: 0.000), MVC (4.07% vs. 9.13%, OR: 0.44, P: 0.002), bleeding (6.40% vs. 12.03%, OR: 0.50, P: 0.003), 30-day mortality (3.29% vs. 5.68%, OR: 0.51, P: 0.000), and stroke (1.48% vs. 2.86%, OR: 0.49, P: 0.014). Device success was higher in the S3V (98.18% vs. 93.76%, OR: 3.14, P: 0.000). Cardiovascular mortality, myocardial infarction, AKI and post-dilatation were not significantly different. Permanent pacemaker implantation (PPI) was higher in S3V recipients (13.29% vs. 9.23%, OR: 1.58, P: 0.000). Procedure time was shorter for the S3V (71.94 vs. 86.85, P: 0.016) and used less contrast volume (129.36 vs. 161.18, P: 0.049). CONCLUSIONS: Patients receiving the S3V had lower risk of PVL, MVC, bleeding, mortality, and stroke. PPI was somewhat higher in the S3V group. S3V implantation was faster and used less contrast.

Optimizing hemodynamics of transcatheter aortic valve-in-valve implantation in 19-mm surgical aortic prostheses.

OBJECTIVE: To demonstrate the feasibility of achieving good hemodynamic results with valve-in-valve transcatheter aortic valve replacement (ViV TAVR) for degenerated 19 mm surgical bioprosthetic valves. BACKGROUND: Considerable controversy exists regarding ViV TAVR within 19mm surgical prostheses due to concerns of elevated valve gradients and mortality. METHODS: Among all patient undergoing ViV TAVR between 7/2016 and 4/2017 for symptomatic severe bioprosthetic aortic stenosis (AS), five had a 19 mm surgical valve in place and were included in this publication. None of the patients had patient-prosthesis mismatch. Aggressive post-dilation was performed in four out of five cases using a special technique we describe below. RESULTS: In all cases, mean aortic valve (AV) gradients significantly improved post-ViV TAVR, particularly after post-dilation. Interestingly, high pressure post-dilation of the ViV resulted in an increase in the diameter of surgical valve stent frame dimensions in nearly all patients who underwent post-dilation. CONCLUSIONS: Good hemodynamic outcome is possible with aggressive post-dilation in patients with 19 mm failed surgical bioprostheses. High-risk patients with 19 mm failed surgical prostheses who do not otherwise have viable surgical options should be considered for ViV TAVR.

On the potential of solid state LED strips utilizing an organic color converter for non-line of sight visible light communication.

LED strip lighting can provide high quality uniform shadow-free diffuse lighting at low cost as numerous emission sources are controlled by a single transformer. Organic LEDs offer the additional advantages of UV free emission and, for visible light communication, picosecond fluorescent lifetimes allowing the whole visible spectrum to be used without filters. Using parameters determined experimentally for solid-state LED strip lighting and fluorescent lifetimes typical of organic phosphors as the input for a Monte Carlo based ray-tracing simulation, we evaluate the potential bandwidths obtainable for indoor communication. Our work suggests that raw data transfer rates of 4 to 10 Mbps are obtainable in a standard 5m by 5m by 3m room compatible with Internet of Things (IoT) applications.

Meta-Analysis of Usefulness of Anticoagulation After Transcatheter Aortic Valve Implantation.

Since the advent of bioprosthetic valves, the implications of long-term anticoagulation after valve replacement are unclear. There are very little data on outcomes of long-term anticoagulation after transcatheter aortic valve implantation (TAVI). Our aim was to conduct a systematic review of literature regarding anticoagulation after TAVI. The existing literature on anticoagulation after bioprosthetic valve replacement was thoroughly reviewed, including the most recent American College of Cardiology/American Heart Association 2017 guidelines for management of valvular disease, which is based on sparse, nonrandomized retrospective data. A systematic review of MEDLINE, EMBASE, and Cochrane CENTRAL databases was conducted to retrieve articles reporting outcomes on anticoagulation after TAVI, and 5 articles were retrieved. Pooled analysis revealed lower bleeding rates in the anticoagulated group (22% vs 35%, p = 0.006). Stroke and mortality were inconsistently reported by the studies. The data regarding outcomes of patients on anticoagulation after TAVI are sparse. Systematic collection of anticoagulation data in the existing registries and future trials should be strongly considered in patients undergoing TAVI.

Local oxidation and reduction of graphene.

Micrometer sized oxidation patterns were created in chemical vapor deposition grown graphene through scanning probe lithography (SPL) and then subsequently reduced by irradiation using a focused x-ray beam. Throughout the process, the films were characterized by lateral force microscopy, micro-Raman and micro-x-ray photoelectron spectroscopy. Firstly, the density of grain boundaries was found to be crucial in determining the maximum possible oxygen coverage with SPL. Secondly, the dominant factor in SPL oxidation was found to be the bias voltage. At low voltages, only structural defects are formed on grain boundaries. Above a distinct threshold voltage, oxygen coverage increased rapidly, with the duration of applied voltage affecting the final oxygen coverage. Finally, we found that, independent of initial conditions, types of defects or the amount of SPL oxidation, the same set of coupled rate equations describes the reduction dynamics with the limiting reduction step being C-C â†’ C=C.