Deconvoluting the Individual Effects of Nanoparticle Proximity and Size in Thermocatalysis.

Nanoparticle (NP) size and proximity are two physical descriptors applicable to practically all NP-supported catalysts. However, with conventional catalyst design, independent variation of these descriptors to investigate their individual effects on thermocatalysis remains challenging. Using a raspberry-colloid-templating approach, we synthesized a well-defined catalyst series comprising Pd12Au88 alloy NPs of three distinct sizes and at two different interparticle distances. We show that NP size and interparticle distance independently control activity and selectivity, respectively, in the hydrogenation of benzaldehyde to benzyl alcohol and toluene. Surface-sensitive spectroscopic analysis indicates that the surfaces of smaller NPs expose a greater fraction of reactive Pd dimers, compared to inactive Pd single atoms, thereby increasing intrinsic catalytic activity. Computational simulations reveal how a larger interparticle distance improves catalytic selectivity by diminishing the local benzyl alcohol concentration profile between NPs, thus suppressing its readsorption and consequently, undesired formation of toluene. Accordingly, benzyl alcohol yield is maximized using catalysts with smaller NPs separated by larger interparticle distances, overcoming activity-selectivity trade-offs. This work exemplifies the high suitability of the modular raspberry-colloid-templating method as a model catalyst platform to isolate individual descriptors and establish clear structure-property relationships, thereby bridging the materials gap between surface science and technical catalysts.

Evaluation of the Hemocompatibility of the Direct Oral Anticoagulant Apixaban in Left Ventricular Assist Devices: The DOAC LVAD Study.

BACKGROUND: Patients receiving left ventricular assist device (LVAD) support require long-term anticoagulation to reduce the risk of thromboembolic complications. Apixaban is a direct oral anticoagulant that has become first-line therapy; however, its safety in LVAD recipients has not been well described. OBJECTIVES: This study sought to investigate whether, in patients with a fully magnetically levitated LVAD, treatment with apixaban would be feasible and comparable with respect to safety and freedom from the primary composite outcome of death or major hemocompatibility-related adverse events (HRAEs) (stroke, device thrombosis, major bleeding, aortic root thrombus, and arterial non-central nervous system thromboembolism) as compared with treatment with warfarin. METHODS: The DOAC LVAD (Evaluation of the Hemocompatibility of the Direct Oral Anti-Coagulant Apixaban in Left Ventricular Assist Devices) trial was a phase 2, open label trial of LVAD recipients randomized 1:1 to either apixaban 5 mg twice daily or warfarin therapy. All patients were required to take low-dose aspirin. Patients were followed up for 24 weeks to evaluate the primary composite outcome. RESULTS: A total of 30 patients were randomized: 14 patients to warfarin and 16 patients to apixaban. The median patient age was 60 years (Q1-Q3: 52-71 years), and 47% were Black patients. The median time from LVAD implantation to randomization was 115 days (Q1-Q3: 56-859 days). At 24 weeks, the primary composite outcome occurred in no patients receiving apixaban and in 2 patients (14%) receiving warfarin (P = 0.12); these 2 patients experienced major bleeding from gastrointestinal sources. CONCLUSIONS: Anticoagulation with apixaban was feasible in patients with an LVAD without an excess of HRAEs or deaths. This study informs future pivotal clinical trials evaluating the safety and efficacy of apixaban in LVAD recipients. (Evaluation of the Hemocompatibility of the Direct Oral Anti-Coagulant Apixaban in Left Ventricular Assist Devices [DOAC LVAD]; NCT04865978).

Utilizing Quality of Life Adjusted Days Alive and Out of Hospital in Heart Failure Clinical Trials.

BACKGROUND: In heart failure (HF) trials, there has been an emphasis on utilizing more patient-centered outcomes, including quality of life (QoL) and days alive and out of hospital. We aimed to explore the impact of QoL adjusted days alive and out of hospital as an outcome in 2 HF clinical trials. METHODS: Using data from 2 trials in HF (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure [GUIDE-IT] and Study of Dietary Intervention under 100 mmol in Heart Failure [SODIUM-HF]), we determined treatment differences using percentage days alive and out of hospital (%DAOH) adjusted for QoL at 18 months as the primary outcome. For each participant, %DAOH was calculated as a ratio between days alive and out of hospital/total follow-up. Using a regression model, %DAOH was subsequently adjusted for QoL measured by the Kansas City Cardiomyopathy Questionnaire Overall Summary Score. RESULTS: In the GUIDE-IT trial, 847 participants had a median baseline Kansas City Cardiomyopathy Questionnaire Overall Summary Score of 59.0 (interquartile range, 40.8-74.3), which did not change over 18 months. %DAOH was 90.76%±22.09% in the biomarker-guided arm and 88.56%±25.27% in the usual care arm. No significant difference in QoL adjusted %DAOH was observed (1.09% [95% CI, -1.57% to 3.97%]). In the SODIUM-HF trial, 796 participants had a median baseline Kansas City Cardiomyopathy Questionnaire Overall Summary Score of 69.8 (interquartile range, 49.3-84.3), which did not change over 18 months. %DAOH was 95.69%±16.31% in the low-sodium arm and 95.95%±14.76% in the usual care arm. No significant difference was observed (1.91% [95% CI, -0.85% to 4.77%]). CONCLUSIONS: In 2 large HF clinical trials, adjusting %DAOH for QoL was feasible and may provide complementary information on treatment effects in clinical trials.

Iterative Bragg peak removal on X-ray absorption spectra with automatic intensity correction.

This study introduces a novel iterative Bragg peak removal with automatic intensity correction (IBR-AIC) methodology for X-ray absorption spectroscopy (XAS), specifically addressing the challenge of Bragg peak interference in the analysis of crystalline materials. The approach integrates experimental adjustments and sophisticated post-processing, including an iterative algorithm for robust calculation of the scaling factor of the absorption coefficients and efficient elimination of the Bragg peaks, a common obstacle in accurately interpreting XAS data, particularly in crystalline samples. The method was thoroughly evaluated on dilute catalysts and thin films, with fluorescence mode and large-angle rotation. The results underscore the technique's effectiveness, adaptability and substantial potential in improving the precision of XAS data analysis. While demonstrating significant promise, the method does have limitations related to signal-to-noise ratio sensitivity and the necessity for meticulous angle selection during experimentation. Overall, IBR-AIC represents a significant advancement in XAS, offering a pragmatic solution to Bragg peak contamination challenges, thereby expanding the applications of XAS in understanding complex materials under diverse experimental conditions.

Diuretic use and outcomes in patients with heart failure with reduced ejection fraction: Insights from the VICTORIA trial.

AIMS: In VICTORIA, vericiguat compared with placebo reduced the risk of cardiovascular death (CVD) and heart failure hospitalization (HFH) in patients enrolled after a worsening heart failure (WHF) event. We examined clinical outcomes and efficacy of vericiguat as it relates to background use of loop diuretics in patients with WHF. METHODS AND RESULTS: We calculated the total daily loop diuretic dose equivalent to furosemide dosing at randomization and categorized these as: no loop diuretic, 1-39, 41-80, 40, and >80 mg total daily dose (TDD). The primary composite outcome of CVD/HFH and its components were evaluated based on TDD loop diuretic and expressed as adjusted hazard ratios with 95% confidence intervals. Post-randomization rates of change in TDD were also examined. Of 4974 patients (98% of the trial) with diuretic dose information available at randomization, 540 (10.8%) were on no loop diuretic, 647 (13.0%) were on 1-39, 1633 (32.8%) were on 40, 1185 (23.8%) were on 41-80, and 969 (19.4%) were on >80 mg TDD. Patients with higher TDD had a higher rate of primary and secondary clinical outcomes. There were no significant interactions with TDD at randomization and efficacy of vericiguat versus placebo for any outcome (all pinteraction > 0.5). Post-randomization diuretic dose changes for vericiguat and placebo showed similar rates of up-titration (19.6 and 20.2/100 person-years), down-titration (16.8 and 18.1/100 person-years), and stopping diuretics (22.9 and 24.2/100 person-years). CONCLUSIONS: Loop diuretic TDD at randomization was independently associated with worse outcomes in this high-risk population. The efficacy of vericiguat was consistent across the range of diuretic doses.

Clinical Trial Inclusion and Impact on Early Adoption of Medical Innovation in Diverse Populations.

BACKGROUND: Inadequate inclusion in clinical trial enrollment may contribute to health inequities by evaluating interventions in cohorts that do not fully represent target populations. OBJECTIVES: The aim of this study was to determine if characteristics of patients with heart failure (HF) enrolled in a pivotal trial are associated with who receives an intervention after approval. METHODS: Demographics from 2,017,107 Medicare patients hospitalized for HF were compared with those of the first 10,631 Medicare beneficiaries who received implantable pulmonary artery pressure sensors. Characteristics of the population studied in the pivotal CHAMPION (CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients) clinical trial (n = 550) were compared with those of both groups. All demographic data were analyzed nationally and in 4 U.S. regions. RESULTS: The Medicare HF cohort included 80.9% White, 13.3% African American, 1.9% Hispanic, 1.3% Asian, and 51.5% female patients. Medicare patients <65 years of age were more likely to be African American (33%) and male (58%), whereas older patients were mostly White (84%) and female (53%). Forty-one percent of U.S. HF hospitalizations occurred in the South; demographic characteristics varied significantly across all U.S. regions. The CHAMPION trial adequately represented African Americans (23% overall, 35% <65 years of age), Hispanic Americans (2%), and Asian Americans (1%) but underrepresented women (27%). The trial's population characteristics were similar to those of the first patients who received pulmonary artery sensors (82% White, 13% African American, 1% Asian, 1% Hispanic, and 29% female). CONCLUSIONS: Demographics of Centers for Medicare and Medicaid Services beneficiaries hospitalized with HF vary regionally and by age, which should be considered when defining "adequate" representation in clinical studies. Enrollment diversity in clinical trials may affect who receives early application of recently approved innovations.

Training the Next Generation of Data Monitoring Committee Members: An Initiative of the Heart Failure Collaboratory.

Clinical trials are vital for assessing therapeutic interventions. The associated data monitoring committees (DMCs) safeguard patient interests and enhance trial integrity, thus promoting timely, reliable evaluations of those interventions. We face an urgent need to recruit and train new DMC members. The Heart Failure Collaboratory (HFC), a multidisciplinary public-private consortium of academics, trialists, patients, industry representatives, and government agencies, is working to improve the clinical trial ecosystem. The HFC aims to improve clinical trial efficiency and quality by standardizing concepts, and to help meet the demand for experienced individuals on DMCs by creating a standardized approach to training new members. This paper discusses the HFC's training workshop, and an apprenticeship model for new DMC members. It describes opportunities and challenges DMCs face, along with common myths and best practices learned through previous experiences, with an emphasis on data confidentiality and need for quality independent statistical reporting groups.

Interrogating site dependent kinetics over SiO2-supported Pt nanoparticles.

A detailed knowledge of reaction kinetics is key to the development of new more efficient heterogeneous catalytic processes. However, the ability to resolve site dependent kinetics has been largely limited to surface science experiments on model systems. Herein, we can bypass the pressure, materials, and temperature gaps, resolving and quantifying two distinct pathways for CO oxidation over SiO2-supported 2 nm Pt nanoparticles using transient pressure pulse experiments. We find that the pathway distribution directly correlates with the distribution of well-coordinated (e.g., terrace) and under-coordinated (e.g., edge, vertex) CO adsorption sites on the 2 nm Pt nanoparticles as measured by in situ DRIFTS. We conclude that well-coordinated sites follow classic Langmuir-Hinshelwood kinetics, but under-coordinated sites follow non-standard kinetics with CO oxidation being barrierless but conversely also slow. This fundamental method of kinetic site deconvolution is broadly applicable to other catalytic systems, affording bridging of the complexity gap in heterogeneous catalysis.

Use of win time for ordered composite endpoints in clinical trials.

Consider the choice of outcome for overall treatment benefit in a clinical trial which measures the first time to each of several clinical events. We describe several new variants of the win ratio that incorporate the time spent in each clinical state over the common follow-up, where clinical state means the worst clinical event that has occurred by that time. One version allows restriction so that death during follow-up is most important, while time spent in other clinical states is still accounted for. Three other variants are described; one is based on the average pairwise win time, one creates a continuous outcome for each participant based on expected win times against a reference distribution and another that uses the estimated distributions of clinical state to compare the treatment arms. Finally, a combination testing approach is described to give robust power for detecting treatment benefit across a broad range of alternatives. These new methods are designed to be closer to the overall treatment benefit/harm from a patient's perspective, compared to the ordinary win ratio. The new methods are compared to the composite event approach and the ordinary win ratio. Simulations show that when overall treatment benefit on death is substantial, the variants based on either the participants' expected win times (EWTs) against a reference distribution or estimated clinical state distributions have substantially higher power than either the pairwise comparison or composite event methods. The methods are illustrated by re-analysis of the trial heart failure: a controlled trial investigating outcomes of exercise training.

Recurrent Hospitalizations and Response to Vericiguat in Heart Failure and Reduced Ejection Fraction.

BACKGROUND: In VICTORIA (Vericiguat Global Study in Subjects With Heart Failure With Reduced Ejection Fraction), vericiguat compared with placebo reduced cardiovascular death or heart failure (HF) hospitalization in patients with HF with reduced ejection fraction. OBJECTIVES: This study explored the association between vericiguat and recurrent hospitalizations and subsequent mortality after HF hospitalization. METHODS: The treatment effect of vericiguat on the burden of HF hospitalizations was evaluated by assessing total HF hospitalization and cardiovascular death in the overall trial and based on baseline N-terminal pro-B-type natriuretic peptide levels with and without adjustment for VICTORIA model covariates (ie, baseline variables associated with the primary endpoint) assessed via the Andersen-Gill method. Associations between vericiguat and recurrent hospitalization and mortality adjusted for VICTORIA model covariates are reported. RESULTS: There were 1,222 total HF hospitalizations and cardiovascular deaths among 2,526 patients in the vericiguat group and 1,336 total events among 2,524 patients in the placebo group (unadjusted HR: 0.89 [95% CI: 0.81-0.97] and adjusted HR: 0.92 [95% CI: 0.84-1.01]). In the subgroup with N-terminal pro-B-type natriuretic peptide levels ≤2,816 pg/mL (ie, Q1 and Q2; median or below), there was a suggestion of a benefit with vericiguat (adjusted HRs of 0.80 [95% CI: 0.64-1.01] and 0.77 [95% CI: 0.62-0.94], respectively) compared with those above this value (adjusted HRs of 1.12 [95% CI: 0.93-1.34] and 0.87 [95% CI: 0.74-1.04] for Q3 and Q4). There was no significant difference in treatment effect between patients with vs without an HF hospitalization. After HF hospitalization, the all-cause mortality rate (events per 100 patient-years) was 48.6 for vericiguat and 44.1 for placebo. CONCLUSIONS: Additional investigation of the association between vericiguat and cardiovascular death and total HF hospitalizations by recurrent event analysis did not show a statistically significant reduction in events. Mortality was high after HF hospitalization, emphasizing the need for further therapies to reduce morbidity and mortality. (Vericiguat Global Study in Subjects With Heart Failure With Reduced Ejection Fraction [VICTORIA]; NCT02861534).

Standardized Definitions for Evaluation of Acute Decompensated Heart Failure Therapies: HF-ARC Expert Panel Paper.

Acute decompensated heart failure (ADHF) is one of the most common reasons for hospitalizations or urgent care and is associated with poor outcomes. Therapies shown to improve outcomes are limited, however, and innovation in pharmacologic and device-based therapeutics are therefore actively being sought. Standardizing definitions for ADHF and its trajectory is complex, limiting the generalizability and translation of clinical trials to effect clinical care and policy change. The Heart Failure Collaboratory is a multistakeholder organization comprising clinical investigators, clinicians, patients, government representatives (including U.S. Food and Drug Administration and National Institutes of Health participants), payors, and industry collaborators. The following expert consensus document is the product of the Heart Failure Collaboratory convening with the Academic Research Consortium, including members from academia, the U.S. Food and Drug Administration, and industry, for the purposes of proposing standardized definitions for ADHF and highlighting important endpoint considerations to inform the design and conduct of clinical trials for drugs and devices in this clinical arena.

Impact of vasodilators on diuretic response in patients with congestive heart failure: A mechanistic trial of cimlanod (BMS-986231).

AIM: To investigate the effects of Cimlanod, a nitroxyl donor with vasodilator properties, on water and salt excretion after an administration of an intravenos bolus of furosemide. METHODS AND RESULTS: In this randomized, double-blind, mechanistic, crossover trial, 21 patients with left ventricular ejection fraction <45%, increased plasma concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and receiving loop diuretics were given, on separate study days, either an 8 h intravenous (IV) infusion of cimlanod (12 µg/kg/min) or placebo. Furosemide was given as a 40 mg IV bolus four hours after the start of infusion. The primary endpoint was urine volume in the 4 h after the bolus of furosemide during infusion of cimlanod compared with placebo. Median NT-proBNP at baseline was 1487 (interquartile range: 847-2665) ng/L. Infusion of cimlanod increased cardiac output and reduced blood pressure without affecting cardiac power index consistent with its vasodilator effects. Urine volume in the 4 h post-furosemide was lower with cimlanod (1032 ± 393 ml) versus placebo (1481 ± 560 ml) (p = 0.002), as were total sodium excretion (p = 0.004), fractional sodium excretion (p = 0.016), systolic blood pressure (p < 0.001), estimated glomerular filtration rate (p = 0.012), and haemoglobin (p = 0.010), an index of plasma volume expansion. CONCLUSIONS: For patients with heart failure and congestion, vasodilatation with agents such as cimlanod reduces the response to diuretic agents, which may offset any benefit from acute reductions in cardiac preload and afterload.

Prognostic Impact of Repeated NT-proBNP Measurements in Patients With Heart Failure With Reduced Ejection Fraction.

BACKGROUND: Although clinical studies have demonstrated the association between a single N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement and clinical outcomes in chronic heart failure, the biomarker is frequently measured serially in clinical practice. OBJECTIVES: The aim of this study was to determine the added prognostic value of repeated NT-proBNP measurements compared with single measurements alone for chronic heart failure patients. METHODS: In the GUIDE-IT (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure) study, 894 study participants with chronic heart failure with reduced ejection fraction were enrolled at 45 outpatient sites in the United States and Canada. Repeated NT-proBNP levels were measured over a 2-year study period. Associations between repeated NT-proBNP measurements and trial endpoints were assessed using a joint longitudinal and survival model. RESULTS: After adjustment for baseline covariates, each doubling of the baseline NT-proBNP level was associated with a HR of 1.17 (95% CI: 1.08-1.28; P = 0.0003) for the primary trial endpoint of cardiovascular death or heart failure hospitalization. Serial measurements increased the adjusted HR for the primary trial endpoint to 1.66 (95% CI: 1.50-1.84; P < 0.0001), and a similar increased risk was observed across secondary trial endpoints. In joint modeling, an increase in NT-proBNP occurred weeks before the onset of adjudicated events. CONCLUSIONS: Repeated NT-proBNP measurements are a strong predictor of outcomes in heart failure with reduced ejection fraction with an increase in concentration occurring well before event onset. These results may support routine NT-proBNP monitoring to assist in clinical decision making. (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure [GUIDE-IT]; NCT01685840).

Left Ventricular Ejection Fraction and the Future of Heart Failure Phenotyping.

Heart failure (HF) is a complex syndrome traditionally classified by left ventricular ejection fraction (LVEF) cutpoints. Although LVEF is prognostic for risk of events and predictive of response to some HF therapies, LVEF is a continuous variable and cutpoints are arbitrary, often based on historical clinical trial enrichment decisions rather than physiology. Holistic evaluation of the treatment effects for therapies throughout the LVEF range suggests the standard categorization paradigm for HF merits modification. The multidisciplinary Heart Failure Collaboratory reviewed data from large-scale HF clinical trials and found that many HF therapies have demonstrated therapeutic benefit across a large range of LVEF, but specific treatment effects vary across that range. Therefore, HF should practically be classified by association with an LVEF that is reduced or not reduced, while acknowledging uncertainty around the precise LVEF cutpoint, and future research should evaluate new therapies across the continuum of LVEF.

Design and Rationale for the Direct Oral Anticoagulant Apixaban in Left Ventricular Assist Devices (DOAC LVAD) Study.

Implantable left ventricular assist device (LVAD) therapy is used to improve quality of life, alleviate symptoms and extend survival rates in patients with advanced heart failure. Patients with LVADs require chronic anticoagulation to reduce the risk of thromboembolic complications, and they commonly experience bleeding events. Apixaban is a direct oral anticoagulant that has become first-line therapy for patients with nonvalvular atrial fibrillation and venous thromboembolism; however, its safety in patients with LVADs has not been well characterized. The evaluation of the hemocompatibility in the DOAC LVAD (Direct Oral Anti-Coagulant apixaban in Left Ventricular Assist Devices) trial is a phase 2, open-label trial of patients with LVADs who were randomized to either apixaban or warfarin therapy. Patients randomized to apixaban will be started on a dosage of 5 mg twice daily, whereas those randomized to warfarin will be managed at an International Normalized Ratio goal of 2.0-2.5. All patients will be treated with aspirin at 81 mg daily. We plan to randomize and follow as many as 40 patients for 24 weeks to evaluate the primary outcomes of freedom from death or hemocompatibility-related adverse events (stroke, device thrombosis, bleeding, aortic root thrombus, and arterial non-CNS thromboembolism). The DOAC LVAD trial will establish the feasibility of apixaban anticoagulant therapy in patients with LVADs. Clinicaltrials.gov: NCT04865978.

Relationship of Race With Functional and Clinical Outcomes With the REHAB-HF Multidomain Physical Rehabilitation Intervention for Older Patients With Acute Heart Failure.

Background The REHAB-HF (Rehabilitation Therapy in Older Acute Heart Failure Patients) randomized trial demonstrated that a 3-month transitional, tailored, progressive, multidomain physical rehabilitation intervention improves physical function, frailty, depression, and health-related quality of life among older adults with acute decompensated heart failure. Whether there is differential intervention efficacy by race is unknown. Methods and Results In this prespecified analysis, differential intervention effects by race were explored at 3 months for physical function (Short Physical Performance Battery [primary outcome], 6-Minute Walk Distance), cognition, depression, frailty, health-related quality of life (Kansas City Cardiomyopathy Questionnaire, EuroQoL 5-Dimension-5-Level Questionnaire) and at 6 months for hospitalizations and death. Significance level for interactions was P≤0.1. Participants (N=337, 97% of trial population) self-identified in near equal proportions as either Black (48%) or White (52%). The Short Physical Performance Battery intervention effect size was large, with values of 1.3 (95% CI, 0.4-2.1; P=0.003]) and 1.6 (95% CI, 0.8-2.4; P<0.001) in Black and White participants, respectively, and without significant interaction by race (P=0.56). Beneficial effects were also demonstrated in 6-Minute Walk Distance, gait speed, and health-related quality of life scores without significant interactions by race. There was an association between intervention and reduced all-cause rehospitalizations in White participants (rate ratio, 0.73 [95% CI, 0.55-0.98]; P=0.034) that appears attenuated in Black participants (rate ratio, 1.06 [95% CI, 0.81-1.41]; P=0.66; interaction P=0.067). Conclusions The intervention produced similarly large improvements in physical function and health-related quality of life in both older Black and White patients with acute decompensated heart failure. A future study powered to determine how the intervention impacts clinical events is required. REGISTRATION URL: https://www.clinicaltrials.gov. Identifier: NCT02196038.