Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

STUDY OF EFFECTIVENESS OF SHELTERING FROM RADIATION EXPOSURE DUE TO ACCIDENTAL RELEASE OF RADIOACTIVITY

Sheltering is one of the important protective actions as a part of emergency response during the early phases of an accident-mostly precautionary in nature. Sheltering via structural shielding reduces the direct exposure from plume/cloud shine and ground shine doses as well as the airborne radioactivity concentration and hence inhalation dose. The present study was aimed at estimating the shielding factor in the case of Indian houses for external exposure pathways using the FLUKA Monte Carlo based radiation transport code. Furthermore, the dose reduction factor due to exposure from the inhalation pathway was estimated using an indoor aerosol model. These factors were assessed for the three major types of dwellings, and they provided important inputs for decision-making for sheltering or evacuation in case of any sudden release of radionuclides into the environment.

Residual ctDNA after treatment predicts early relapse in patients with early-stage non-small cell lung cancer

BACKGROUND

Identification of residual disease in patients with localized non-small cell lung cancer (NSCLC) following treatment with curative intent holds promise to identify patients at risk of relapse. New methods can detect circulating tumour DNA (ctDNA) in plasma to fractional concentrations as low as a few parts per million, and clinical evidence is required to inform their use.

PATIENTS AND METHODS

We analyzed 363 serial plasma samples from 88 patients with early-stage NSCLC (48.9%/28.4%/22.7% at stage I/II/III), predominantly adenocarcinomas (62.5%), treated with curative intent by surgery (n = 61), surgery and adjuvant chemotherapy/radiotherapy (n = 8), or chemoradiotherapy (n = 19). Tumour exome sequencing identified somatic mutations and plasma was analyzed using patient-specific RaDaR™ assays with up to 48 amplicons targeting tumour-specific variants unique to each patient.

RESULTS

ctDNA was detected before treatment in 24%, 77% and 87% of patients with stage I, II and III disease, respectively, and in 26% of all longitudinal samples. The median tumour fraction detected was 0.042%, with 63% of samples <0.1% and 36% of samples <0.01%. ctDNA detection had clinical specificity >98.5% and preceded clinical detection of recurrence of the primary tumour by a median of 212.5 days. ctDNA was detected after treatment in 18/28 (64.3%) of patients who had clinical recurrence of their primary tumour. Detection within the landmark timepoint 2 weeks to 4 months after treatment end occurred in 17% of patients, and was associated with shorter recurrence-free survival [hazard ratio (HR): 14.8, P <0.00001] and overall survival (HR: 5.48, P <0.0003). ctDNA was detected 1-3 days after surgery in 25% of patients yet was not associated with disease recurrence. Detection before treatment was associated with shorter overall survival and recurrence-free survival (HR: 2.97 and 3.14, P values 0.01 and 0.003, respectively).

CONCLUSIONS

ctDNA detection after initial treatment of patients with early-stage NSCLC using sensitive patient-specific assays has potential to identify patients who may benefit from further therapeutic intervention.

Relationship Between the Mobility of Aggregates and Fluid Penetration Depth Across a Range of Fractal Dimensions Using Stokesian Dynamics

The hydrodynamic behavior of fractal aggregates plays an important role in various applications in industry and the environment, and has been a topic of interest over the past several decades. Despite this, crucial aspects such as the relationship of the mobility radius, R_m, with respect to the fractal dimension, d_f, and the fluid penetration depth, δ, have largely remained unexplored. Herein, we examine these aspects across a wide range of d_f's through a Stokesian dynamics approach. It takes into account all orders of monomer-monomer interactions to construct the resistance matrix for the entire cluster, which is assumed to be rigid. Statistical fractals created using algorithms such as diffusion limited aggregation (DLA), cluster-cluster aggregation (CCA), tunable Monte Carlo algorithm, and a deterministic Vicsek fractal, with d_f varying from 1.76 to 3, and the number of monomers ranging from 20 to 10 240 are considered. While confirming the expected asymptotic cluster-size independence of the hydrodynamic ratio, β = R_m/R_g (where R_g is the radius of gyration of the cluster), this study reveals a monotonically increasing trend for β with increasing d_f. The decay of the fluid velocity within the aggregate is quantified via the concept of penetration depth (δ). Analysis shows that the dimensionless penetration depth (δ* = δ/R_g) approaches asymptotic constancy with respect to cluster size in contrast to a weak dependency of the form δ* ∼ (R_g/a)^{-(d_f - 1)/2}, predicted by the mean-field theory (a being the monomer radius). Furthermore, the penetration depth is found to decrease rapidly, in an exponential manner, with increasing β. This establishes a quantitative relationship between the resistance experienced by the cluster and the degree of penetration of fluid into it. The implications of these results are further discussed.

Dose distribution to a random walker moving in a two-dimensional surface around a radioactive source

BACKGROUND

Modeling of dose distribution of randomly moving population around a radioactive source is a complex problem.

OBJECTIVE

The objective is to develop a model and solution techniques to estimate radiation absorbed dose to the population randomly moving around a radioactive source.

METHODS

The problem is formulated using a second-order partial differential equation; different moments of the dose distribution function are defined related to physically realizable quantities, and solutions are obtained using standard moments methods. Alternatively, numerical simulations are performed to estimate the radiation doses using Monte Carlo approach for individual positions and random motions of the people around the source.

RESULTS

A good agreement is found between average doses obtained from moments method and numerical simulations. A typical application of this model to different exposure conditions shows that the average dose is highly dependent on the population density. The study results show that average dose decreases with increase in the population density and movement area of random walker.

SIGNIFICANCE

This mathematical model can be used as a rapid assessment tool by the emergency planners in resource optimization by providing quick estimates of likely exposures for triage and emergency response.

Enhancing MRI Brain Images Using Contourlet Transform and Adaptive Histogram Equalization

Human brain can be viewed using MRI images. These images will be useful for physicians, only if their quality is good. We propose a new method called, Contourlet Based Two Stage Adaptive Histogram Equalization (CBTSA), that uses Nonsubsampled Contourlet Transform (NSCT) for smoothing images and adaptive histogram equalization (AHE), under two occasions, called stages, for enhancement of the low contrast MRI images. The given MRI image is fragmented into equal sized sub-images and NSCT is applied to each of the sub-images. AHE is imposed on each resultant sub-image. All processed images are merged and AHE is applied again to the merged image. The clarity of the output image obtained by our method has outperformed the output image produced by traditional methods. The quality was measured and compared using criteria like, Entropy, Absolute Mean Brightness Error (AMBE) and Peak Signal to Noise Ratio (PSNR).

Recovery potential of cavitation-induced injured cells of common spore-forming bacteria in skim milk exposed to ultrasonication

•

Ultrasonication is a new technique that could lower bacterial counts in milk.

•

Ultrasonication treatment may cause injury to the bacterial cells.

•

Holding the cavitated milk helps the bacteria to recover and return to normalcy.

The presence of spore-forming microorganisms and their adhesion to contact surfaces in dairy plants is a major concern because dairy products are prone to cross-contamination. Spore formers and their spores can survive milk processing treatments due to their heat resistance. One source of these spore formers is bacterial biofilms, which grow and accumulate on most surfaces in dairy industrial plants, such as pipes, heat exchangers, pasteurized plates, and storage tanks. Their endospores form biofilms by attaching to these surfaces and germinating when conditions become more favorable. The cross-contamination of dairy products by bacterial biofilms may lead to reduced shelf life and spoilage. To minimize the problem caused by thermoduric bacteria, the dairy industry adopts several approaches. Pasteurization is an irreplaceable technique for milk processing. Unfortunately, some bacteria and endospores are resistant to heat treatment, which can grow and cause spoilage of dairy products. Thus, alternative approaches that could help to reduce microbial counts are needed. In our previous study, we demonstrated the effectiveness of ultrasonication to inactivate spore formers and reduce the overall microbial counts in milk. In the current study, we investigated the recovery of cavitation-induced injured cells during the storage of ultrasonicated skim milk. Three common spore formers—Geobacillus stearothermophilus (ATCC 15952), Bacillus licheniformis (ATCC 6634), and Bacillus sporothermodurans (DSM 10599)—were selected to conduct challenge studies by inoculating skim milk samples and exposing them to ultrasonication (10 min each at 80% amplitude). This treatment was done in an ice bath to control the resultant temperature increase. The ultrasonicated skim milk samples were then held for 1, 2, 4, or 12 h in the refrigerator (4°C) to study the recovery of cells following cavitation-induced injury. Ultrasonication resulted in cell injury, as demonstrated by scanning electron microscopy. The injured cells can potentially recover under appropriate conditions during the storage of ultrasonicated milk and could affect the microbiological quality of milk and products manufactured with such milk. The respective bacterial counts for the 3 organisms in the spiked skim milk, on average, were approximately 6.0 log cfu/mL; immediately after ultrasonication, these counts decreased to 3.50 ± 0.02, 4.38 ± 0.02, and 3.75 ± 0.05 log cfu/mL for G. stearothermophilus, B. licheniformis, and B. sporothermodurans, respectively. During 12 h of subsequent incubation at 4°C, their counts increased to 4.17 ± 0.05, 5.25 ± 0.1, and 5.69 ± 0.06 log cfu/mL, respectively. All experiments were done in triplicate for all 3 bacteria. To conclude, slow recovery of injured cells of spore-forming bacteria is possible in ultrasonicated milk during storage under refrigeration conditions.

Application of multipoint dose rate measurement for radioactive inventory estimation in waste drums

Dose-to-Curie (DTC) conversion is a fast and simple method for quantification of radionuclide content in solid waste packages with a prior knowledge of waste matrix and radionuclide composition of the waste stream. A dose to curie conversion factor generated based on an assumed radioactivity distribution in the package is used for conversion of the measured dose rate to activity. The difference between the radionuclide distribution for drum from field and the assumed distribution is a major source of error in activity estimation using this technique. In this work, the systematic error of DTC method, due to the spatial variation of a single hot-spot in 200 L solid waste drum is subjected to systematic analysis using Monte-Carlo simulation. Data analysis was carried out with 1920 source locations within the drum and up to sixteen measurement points for dose rates around the drum. The span of error obtained for different configurations of detectors were compared to optimise the waste drum assay system. The general trends observed in simulation were found to be in good agreement with the experimental measurements done using a ¹³⁷Cs (318.2 MBq) standard source placed at selected locations. The results presented here clearly establish the advantage of multipoint dose rate measurement to improve the accuracy in activity estimation using DTC method.

Effective lightweight, flexible and ultrathin PVDF/rGO/Ba2Co2Fe12O22composite films for electromagnetic interference shielding applications

In this study, we developed a simple and cost-effective solvent film casting method to fabricate ultrathin, flexible and lightweight polyvinylidenefluoride (PVDF)-based composites that provide high electromagnetic interference (EMI) shielding performance. Y-type barium hexaferrite with general formula Ba₂Co₂Fe₁₂O₂₂was first synthesized by the sol-gel autocombustion method and then reduced graphene oxide (rGO) was prepared by modified Hummer's method. The crystal structure, morphology, elemental surface analysis and magnetic properties of the samples were systematically investigated using x-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, high-resolution scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy and vibrating sample magnetometry. Then, the complex permittivity, complex permeability and EMI shielding properties of the flexible PVDF/rGO/Ba₂Co₂Fe₁₂O₂₂composite films with two different amounts of Ba₂Co₂Fe₁₂O₂₂NP content and a fixed amount of rGO content were investigated using a vector network analyzer. The structural characterizations of the resultant composite films showed the formation of an electroactiveβ-phase of PVDF with addition of Ba₂Co₂Fe₁₂O₂₂nanoparticles and rGO content. The enhancement of theβ-phase in the PVDF/rGO/Ba₂Co₂Fe₁₂O₂₂nanocomposites was explained from a physicochemical viewpoint. Furthermore, the electrically conductive and magnetic properties of PVDF composite films incorporating rGO and Ba₂Co₂Fe₁₂O₂₂NPs exhibited a high EMI shielding effectiveness of 25.63 dB, with an absorption-dominated shielding feature in the 8-12 GHz region. The enhanced absorption was attributed to the electrostatic interaction induced by theβ-phase fraction in the PVDF matrix, and subsequently from multiple reflections and magnetic loss originating from the synergetic effect of rGO and Ba₂Co₂Fe₁₂O₂₂NPs. This study introduces a low-cost and scalable method for the design of novel, lightweight, flexible and efficient EMI shielding composite films with promising prospects for application in the construction, electronics and aerospace fields.

Assessment of Performance of Blind Center Lathe Operators

Although sight is generally considered to be necessary for the performance of most industrial jobs, this study found that blind persons can be trained to operate a center lathe and to perform various tasks on it accurately. The study assessed the blind subjects’ efficiency of performance of tasks when they utilized various adjustments to the lathe and to procedures that had been developed earlier specifically for blind people. It was found that the efficiency of the blind subjects, compared to that of sighted lathe operators, was 85 percent for moderately complex jobs. The factors of complexity, repetition, and mode of presentation of specifications had some bearing on the speed of work. The study demonstrated that even under adverse conditions, blind lathe operators can achieve satisfactory results.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Why don't they do it? Handwashing barriers and influencer study in Faridabad district, India

BACKGROUND

Handwashing has been widely accepted as the simplest protection against communicable diseases. However, despite proven effectiveness and cost-efficiency, adoption of regular handwashing is still poor in developing countries. As children in school-going age are vulnerable and continue to suffer from preventable illnesses, this study aims to spot barriers to handwashing among children while simultaneously recognizing the influencing factors to aid the solutions narrative for effective water, sanitation and hygiene (WASH) strategies.

METHODS

A school-based cross-sectional, mixed-method study was conducted in Ballabhgarh block, Faridabad district, India. A predesigned, pretested, structured questionnaire was administered to 106 class V students in five randomly selected rural government primary schools. Due permissions, consent and ethical clearances were taken.

RESULTS

The majority (>91%) of children were found to have low illness threat perception. The inability to visually see germs came out as one of the biggest barriers (46%) that were preventing children from practicing regular handwashing. Family, teachers and peers were found to be the most important sources of information for children and not any particular media channel. In fact, role of peers was found to be critical as 72% children said that they would wash hands if their friends were also washing hands.

CONCLUSION

This study suggests children's need for visible proof of germs and associated casual attitude toward illness threat as a hitherto unexplored potential barrier to practicing regular handwashing. In addition, the human channel of communication seems to be the most relevant regarding public health messaging in rural heartlands. Despite 100% penetration of mobile phones and commonplace presence of television, it is the community ecosystem that is still the most trusted sources of information and influence. The unique role of peers found in this study could have strategic implications for future behaviour change interventions making a case for peer-to-peer behaviour modeling.

The Surfaces of the Ceratonia siliqua L. (Carob) Leaflet: Insights from Physics and Chemistry

The production of superhydrophobic coatings inspired by the surface of plant leaves is a challenging goal. Such coatings hold a bright technological future in niche markets of the aeronautical, space, naval, building, automobile, and biomedical sectors. This work is focused on the adaxial (top) and abaxial (bottom) surfaces of the leaflet of the Ceratonia silique L. (carob), a high-commercial-value Mediterranean tree cultivated in many regions of the world. The adaxial and abaxial surfaces feature hydrophobic and superhydrophobic behaviors, respectively. Their chemical composition is very simple: monopalmitin ester and palmitic acid are protuberant in the epicuticular and intracuticular wax layers of the adaxial surface, respectively, whereas 1-octacosanol dominates in the abaxial wax layers. In both surfaces, epicuticular wax is organized along a randomly oriented and intricate network of nanometer-thick and micrometer-long plates, whose density and degree of interconnection are significantly higher in the abaxial surface. The measured tilting angles for the abaxial surface (12-70°) reveal unusual variable density and water adhesion of the nanostructured plate-based texture. Optical measurements demonstrate that light reflectance/absorbance of the glaucous abaxial surface is significantly higher/lower than that of the nonglaucous adaxial surface. In both surfaces, diffuse reflectance is dominant, and the absorbance is weakly dependent on the light incidence angle. We show that the highly dense nanostructured platelike texture of the epicuticular abaxial layer of the C. siliqua leaflet works as a sophisticated light and water management system: it reflects solar radiation diffusely to lower the surface temperature, and it has superhydrophobic character to keep the surface dry. Such attributes enable efficient gas exchange (photosynthesis and respiration), transpiration, and evaporation. To mimic for the first time the abaxial surface, a templation approach was adopted using poly(dimethylsiloxane) (PDMS)/poly(methylphenylsiloxane) (PMPS) positive/negative replicas and a soft polymer/siloxane negative replica produced by the sol-gel process. Because high topographical variations of the biotemplate and wax adhesion to the biohybrid film affected the replication quality, the reproduction of the wax texture via the synthesis of 1-octacosanol-grafted siloxane-based hybrid materials is proposed as a suitable route to duplicate the abaxial surface with high fidelity. The natural chemical/physical strategy adopted by the C. siliqua leaflet to face the harsh Mediterranean climate is a powerful source of bioinspiration for the development of diffuse reflecting and superhydrophobic material systems with foreseen applications as dual-functional antiglare and water-repelling coatings.

Size distribution of virus laden droplets from expiratory ejecta of infected subjects

For rebooting economic activities in the ongoing COVID-19 pandemic scenario, it is important to pay detailed attention to infection transfer mechanisms during interaction of people in enclosed environments. Utmost concern is the possibility of aerosol mediated infection transfer, which is largely governed by the size distributions of virus laden droplets, termed as virusols in this work, ejected from humans. We expand on the well-known theory of Poisson fluctuations which acts as statistical barrier against formation of virusols. Analysis suggests that for viral loads < 2 × 105 RNA copies/mL, often corresponding to mild-to-moderate cases of COVID-19, droplets of diameter < 20 µm at the time of emission (equivalent to ~ 10 µm desiccated residue diameter) are unlikely to be of consequence in carrying infections. Cut-off diameters below which droplets will be practically free of contamination, are presented as a function of viral loading. The median diameters of virus laden polydisperse droplet distributions will be 1.5 to 20 times higher depending upon the geometric standard deviation. The studies have implications to risk assessment as well as residence time estimates of airborne infections in indoor environments. Additionally, it will be also helpful for performance evaluation of sanitization and control technologies to mitigate infection risks in workplaces.

Independent recurrent evolution of MICRORNA genes converging onto similar non-canonical organisation across green plant lineages is driven by local and segmental duplication events in species, family and lineages

The relationship between evolutionary history, organisation and transcriptional regulation of genes are intrinsically linked. These have been well studied in canonically organised protein-coding genes but not of MIRNAs. In the present study, we investigated the non-canonical arrangement of MIRNAs across taxonomic boundaries from algae to angiosperms employing a combination of genome organization, phylogeny and synteny. We retrieved the complete dataset of MIRNA from twenty-five species to identify and classify based on organisational patterns. The median size of cluster was between 2-5 kb and between 1-20 % of all MIRNAs are organized in head-to-head (with bidirectional promoter), head-to-tail (tandem), and overlapping manner. Although majority of the clusters are composed of MIRNA homologs, 25% of all clusters comprises of non-homologous genes with a potential of generating functional and regulatory complexity. A comparison of phylogeny and organizational patterns revealed that multiple independent events, some of which are species-specific, and some ancient, in different lineages, are responsible for non-canonical organization. Detailed investigation of MIR395 family across the plants revealed a complex origin of non-canonical arrangement through ancient and recent, segmental and local duplications; analysis of MIR399 family revealed major expansion occurred prior to monocot-dicot split, with few lineage-specific events. Evolution of "convergent" organization pattern of non-canonical arrangement originating from independent loci through recurrent event highlights our poor understanding of evolutionary process of MIRNA genes. The present investigation thus paves way for comparative functional genomics to understand the role of non-canonical organization on transcriptional regulation and regulatory diversity in MIRNA gene families.

Paradigm shift in efforts to end TB by 2025

TB is a deadly infectious disease, in existence since time immemorial. This article traces the journey of TB developments in the last few decades and the path breaking moments that have accelerated the efforts towards Ending TB from National Tuberculosis Control Program (NTCP 1962-1992) to Revised National Tuberculosis Control Program (RNTCP - 1992-2019) and to National Tuberculosis Elimination Program (NTEP) as per the vision of Honorable Prime Minister of India. From increased funding for TB, the discovery of newer drugs and diagnostics, increased access to health facilities, greater investment in research and expanded reach of public health education, seasoned with TB activism and media's proactive role, private sector participation to political advocacy and community engagement, coupled with vaccine trials has renewed the hope of finding the elusive and miraculous breakthrough to END TB and it seems the goal is within the realms of the possibility. The recent paradigm shift in the policy and the drive of several states & UTs to move towards TB free status through rigorous population-based vulnerability mapping and screening coupled with active case finding is expected to act as the driving force to lead the country towards Ending TB by 2025. Continued investments in research, innovations and availability of more effective drugs and the vaccines will add to existing armamentarium towards Ending TB.

Utilization of cardiac MRI for the assessment of suspected rejection with negative biopsy in heart transplant recipients

Background

Heart transplant (HTx) patients can develop graft dysfunction (GD) without biopsy evidence of cell or antibody mediated rejection. Cardiac MRI (CMR) can detect inflammatory or infiltrative causes of cardiomyopathy however CMR findings in HTx recipients with GD have not been previously described.

Purpose

We sought to identify CMR characteristics of HTx patients with GD, and evaluate its additive value in its diagnosis and prognosis.

Methods

CMR has been performed routinely to evaluate GD at our institutions. There were 37 HTx recipients who presented with acute decline in left ventricular ejection fraction (LVEF) of &lt;50% and &gt;10% from baseline, with no biopsy evidence of rejection between 2007 and 2018. Coronary angiogram with IVUS was done to rule out allograft vasculopathy. Treatment of GD was per discretion of the treating clinician. Responders were defined as those with LVEF improvement &gt;10% at 180 days or greater post-presentation. LV and RV indices, the presence and pattern of late gadolinium enhancement (LGE) were determined by CMR.

Results

There were 34% females and mean age at transplant was 49±13 years. Median time from HTx to GD was 1.2 years. Presenting symptoms were heart failure (n=25), cardiogenic shock (n=1) and 11 patients were asymptomatic. Mean LVEF at presentation was 37±12% and donor specific antibodies were detected in 38% patients. Most patients were treated with steroid bolus (n=29), and/or plasmapheresis (n=23). There were no major changes made in immunosuppression in 6 patients. Delayed enhancement MRI was performed with standard inversion-recovery (IR) gradient echo sequences, between 5 and 20 minutes after institutional-standard protocol administration of IV gadolinium contrast. Biventricular LGE was present in 18/37 (49%) patients with GD and was more prevalent in responders (57%, 13 of 23) than non-responders (35%, 5 of 14), although not statistically significant (p=0.21). There were two patterns of LGE noted: 1) Diffuse epicardial (10 patients out which 9 were responders) and 2) Patchy pattern with non-specific distribution (8 patients out of which 4 were responders). Myocardial edema by triple IR sequencing was seen in 6 patients, all having diffuse epicardial pattern of enhancement matching the delayed enhancement pattern. When comparing different treatment groups, among those treated for GD (n=31), 12 of 21 (57%) responders had LGE and 4 of 10 (40%) non-responders had LGE (p=0.37), a pattern similar to the broader population. Among those not treated for GD (n=6), 1 of 2 responders had LGE and 1 of 4 non-responders had LGE (p=0.5).

Conclusion

CMR identified inflammation as a potential cause of GD in approximately 50% of HTx patients. There are 2 distinct patterns of LGE observed in GD, diffuse epicardial (56%) and patchy (44%). Although the presence of LGE in itself is not associated with myocardial recovery, 90% of patients with a diffuse epicardial pattern have recovery of GD.

Funding Acknowledgement

Type of funding source: None

CHA2DS2-VASc and CHADS2 scores for risk stratification of major adverse cardiovascular events in the COMPASS trial

Background

The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) trial demonstrated that the combination therapy of rivaroxaban and aspirin reduced major adverse cardiovascular events (MACE) compared to aspirin alone in patients with chronic coronary artery disease (CAD) and/or peripheral artery disease (PAD).

Purpose

We assessed whether the CHA2DS2-VASc (congestive heart failure (CHF), hypertension, age ≥75 years, diabetes, stroke/transient ischemic attack (TIA)/thromboembolism, vascular disease, age 65–75 years, and sex category) and CHADS2 (CHF, hypertension, age ≥75 years, diabetes, stroke/TIA) scores used to predict the risk of stroke in patients with atrial fibrillation, can be used identify vascular patients at highest risk of recurrent events who may derive greatest benefits of treatment.

Methods

In COMPASS patients, the predictive accuracy of CHA2DS2-VASc and CHADS2 scores were assessed for MACE, bleeding and net clinical benefit using Cox proportional hazards model. Kaplan-Meier estimates of cumulative risk and absolute risk differences were used to examine the effects of rivaroxaban plus aspirin compared with aspirin alone over 30 months according to risk score categories.

Results

In 27,395 participants with CAD and/or PAD, a high CHA2DS2-VASc score (6–9) was associated with 3 times greater absolute risk of MACE compared to a low score (1–2) (hazard ratio=3.39, 95% CI: 2.54–4.51, p&lt;0.0001). The effects of combination therapy with rivaroxaban and aspirin on MACE, bleeding and net clinical benefit were consistent across CHA2DS2-VASc and CHADS2 score categories, with the greatest benefit in those with the highest risk scores (Figure 1). The greatest reduction in MACE with rivaroxaban and aspirin compared to aspirin only was observed in patients treated for 30 months with highest CHA2DS2-VASc score (6–9) (23 events per 1000 patients prevented) or highest CHADS2 score (3–6) (25 events per 1000 patients prevented). There was increased bleeding in patients with higher CHA2DS2-VASc and CHADS2 scores, but net clinical benefit was preserved across all risk categories and was greatest in those with the highest risk scores.

Conclusion

The CHA2DS2-VASc or CHADS2 scores can be used in patients with chronic CAD and/or PAD to identify patients who are at highest risk of MACE, and therefore likely to achieve the greatest benefit of dual pathway inhibition with the combination of rivaroxaban and aspirin compared with aspirin alone.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): This study was sponsored by Bayer AG.