61 research outputs found
Prospective Evaluation of the Influence of Iterative Reconstruction on the Reproducibility of Coronary Calcium Quantification in Reduced Radiation Dose 320 Detector Row CT.
BACKGROUND: Coronary artery calcium (CAC) predicts coronary heart disease events and is important for individualized cardiac risk assessment. This report assesses the interscan variability of CT for coronary calcium quantification using image acquisition with standard and reduced radiation dose protocols and whether the use of reduced radiation dose acquisition with iterative reconstruction (IR; reduced-dose/IR ) allows for similar image quality and reproducibility when compared to standard radiation dose acquisition with filtered back projection (FBP; standard-dose/FBP ) on 320-detector row computed tomography (320-CT).
METHODS: 200 consecutive patients (60 ± 9 years, 59% male) prospectively underwent two standard- and two reduced-dose acquisitions (800 total scans, 1600 reconstructions) using 320 slice CT and 120 kV tube voltage. Automated tube current modulation was used and for reduced-dose scans, prescribed tube current was lowered by 70%. Image noise and Agatston scores were determined and compared.
RESULTS: Regarding stratification by Agatston score categories (0, 1-10, 11-100, 101-400, \u3e400), reduced-dose/IR versus standard-dose/FBP had excellent agreement at 89% (95% CI: 86-92%) with kappa 0.86 (95% CI: 0.81-0.90). Standard-dose/FBP rescan agreement was 93% (95% CI: 89-96%) with kappa = 0.91 (95% CI: 0.86-0.95) while reduced-dose/IR rescan agreement was similar at 91% (95% CI: 87-94%) with kappa 0.88 (95% CI: 0.83-0.93). Image noise was significantly higher but clinically acceptable for reduced-dose/IR (18 Hounsfield Unit [HU] mean) compared to standard-dose/FBP (16 HU; p \u3c 0.0001). Median radiation exposure was 74% lower for reduced- (0.37 mSv) versus standard-dose (1.4 mSv) acquisitions.
CONCLUSION: Rescan agreement was excellent for reduced-dose image acquisition with iterative reconstruction and standard-dose acquisition with filtered back projection for the quantification of coronary calcium by CT. These methods make it possible to reduce radiation exposure by 74%.
CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/ct2/show/NCT01621594.
UNIQUE IDENTIFIER: NCT01621594
Statins and Exercise Training Response in Heart Failure Patients: Insights From HF-ACTION.
OBJECTIVES: The aim of this study was to assess for a treatment interaction between statin use and exercise training (ET) response.
BACKGROUND: Recent data suggest that statins may attenuate ET response, but limited data exist in patients with heart failure (HF).
METHODS: HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) was a randomized trial of 2,331 patients with chronic HF with ejection fraction ≤35% who were randomized to usual care with or without ET. We evaluated whether there was a treatment interaction between statins and ET response for the change in quality of life and aerobic capacity (peak oxygen consumption and 6-min walk distance) from baseline to 3 months. We also assessed for a treatment interaction among atorvastatin, simvastatin, and pravastatin and change in these endpoints with ET. Multiple linear regression analyses were performed for each endpoint, adjusting for baseline covariates.
RESULTS: Of 2,331 patients in the HF-ACTION trial, 1,353 (58%) were prescribed statins at baseline. Patients treated with statins were more likely to be older men with ischemic HF etiology but had similar use of renin angiotensin system blockers and beta-blockers. There was no evidence of a treatment interaction between statin use and ET on changes in quality of life or exercise capacity, nor was there evidence of differential association between statin type and ET response for these endpoints (all p values \u3e0.05).
CONCLUSIONS: In a large chronic HF cohort, there was no evidence of a treatment interaction between statin use and short-term change in aerobic capacity and quality of life with ET. These findings contrast with recent reports of an attenuation in ET response with statins in a different population, highlighting the need for future prospective studies. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437)
Rationale and design of the GUIDE-IT study: Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure.
OBJECTIVES: The GUIDE-IT (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure) study is designed to determine the safety, efficacy, and cost-effectiveness of a strategy of adjusting therapy with the goal of achieving and maintaining a target N-terminal pro-B-type natriuretic peptide (NT-proBNP) level of
BACKGROUND: Elevations in natriuretic peptide (NP) levels provide key prognostic information in patients with HF. Therapies proven to improve outcomes in patients with HF are generally associated with decreasing levels of NPs, and observational data show that decreases in NP levels over time are associated with favorable outcomes. Results from smaller prospective, randomized studies of this strategy thus far have been mixed, and current guidelines do not recommend serial measurement of NP levels to guide therapy in patients with HF.
METHODS: GUIDE-IT is a prospective, randomized, controlled, unblinded, multicenter clinical trial designed to randomize approximately 1,100 high-risk subjects with systolic HF (left ventricular ejection fraction ≤40%) to either usual care (optimized guideline-recommended therapy) or a strategy of adjusting therapy with the goal of achieving and maintaining a target NT-proBNP level of
CONCLUSIONS: The GUIDE-IT study is designed to definitively assess the effects of an NP-guided strategy in high-risk patients with systolic HF on clinically relevant endpoints of mortality, hospitalization, quality of life, and medical resource use. (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure [GUIDE-IT]; NCT01685840)
Effect of Natriuretic Peptide-Guided Therapy on Hospitalization or Cardiovascular Mortality in High-Risk Patients With Heart Failure and Reduced Ejection Fraction: A Randomized Clinical Trial.
Importance: The natriuretic peptides are biochemical markers of heart failure (HF) severity and predictors of adverse outcomes. Smaller studies have evaluated adjusting HF therapy based on natriuretic peptide levels ( guided therapy ) with inconsistent results.
Objective: To determine whether an amino-terminal pro-B-type natriuretic peptide (NT-proBNP)-guided treatment strategy improves clinical outcomes vs usual care in high-risk patients with HF and reduced ejection fraction (HFrEF).
Design, Settings, and Participants: The Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure (GUIDE-IT) study was a randomized multicenter clinical trial conducted between January 16, 2013, and September 20, 2016, at 45 clinical sites in the United States and Canada. This study planned to randomize 1100 patients with HFrEF (ejection fraction ≤40%), elevated natriuretic peptide levels within the prior 30 days, and a history of a prior HF event (HF hospitalization or equivalent) to either an NT-proBNP-guided strategy or usual care.
Interventions: Patients were randomized to either an NT-proBNP-guided strategy or usual care. Patients randomized to the guided strategy (n = 446) had HF therapy titrated with the goal of achieving a target NT-proBNP of less than 1000 pg/mL. Patients randomized to usual care (n = 448) had HF care in accordance with published guidelines, with emphasis on titration of proven neurohormonal therapies for HF. Serial measurement of NT-proBNP testing was discouraged in the usual care group.
Main Outcomes and Measures: The primary end point was the composite of time-to-first HF hospitalization or cardiovascular mortality. Prespecified secondary end points included all-cause mortality, total hospitalizations for HF, days alive and not hospitalized for cardiovascular reasons, the individual components on the primary end point, and adverse events.
Results: The data and safety monitoring board recommended stopping the study for futility when 894 (median age, 63 years; 286 [32%] women) of the planned 1100 patients had been enrolled with follow-up for a median of 15 months. The primary end point occurred in 164 patients (37%) in the biomarker-guided group and 164 patients (37%) in the usual care group (adjusted hazard ratio [HR], 0.98; 95% CI, 0.79-1.22; P = .88). Cardiovascular mortality was 12% (n = 53) in the biomarker-guided group and 13% (n = 57) in the usual care group (HR, 0.94; 95% CI; 0.65-1.37; P = .75). None of the secondary end points nor the decreases in the NT-proBNP levels achieved differed significantly between groups.
Conclusions and Relevance: In high-risk patients with HFrEF, a strategy of NT-proBNP-guided therapy was not more effective than a usual care strategy in improving outcomes.
Trial Registration: clinicaltrials.gov Identifier: NCT01685840
Differences in NT-proBNP Response and Prognosis in Men and Women With Heart Failure With Reduced Ejection Fraction.
Background NT-proBNP (N-terminal pro-B-type natriuretic peptide) is a prognostic biomarker in heart failure (HF) with reduced ejection fraction. However, it is unclear whether there is a sex difference in NT-proBNP response and whether the therapeutic goal of NT-proBNP ≤1000 pg/mL has equivalent prognostic value in men and women with HF with reduced ejection fraction. Methods and Results In a secondary analysis of the GUIDE-IT (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment) trial we analyzed trends in NT-proBNP and goal attainment by sex. Differences in clinical characteristics, HF treatment, and time to all-cause death or HF hospitalization were compared. Landmark analysis at 3 months determined the prognostic value of early NT-proBNP goal achievement in men and women. Of the 286 (32%) women and 608 (68%) men in the GUIDE-IT trial, women were more likely to have a nonischemic cause and shorter duration of HF. Guideline-directed medical therapy was less intense over time in women. The absolute NT-proBNP values were consistently lower in women; however, the change in NT-proBNP and clinical outcomes were similar. After adjustment, women achieving the NT-proBNP goal had an 82% reduction in death or HF hospitalization compared with a 59% reduction in men. Conclusions Men and women with HF with reduced ejection fraction had a similar NT-proBNP response despite less intensive HF treatment among women. However, compared with men, the early NT-proBNP goal of ≤1000 pg/mL had greater prognostic value in women. Future efforts should be aimed at intensifying guideline-directed medical therapy in women, which may result in greater NT-proBNP reductions and improved outcomes in women with HF with reduced ejection fraction. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01685840
Sodium–glucose co-transporter-2 inhibitors for hospitalised patients with COVID-19: a prospective meta-analysis of randomised trials
Sodium glucose co-transporter-2 inhibitors (SGLT2i) have been proposed as a potential treatment for 3 adults hospitalised with COVID-19, due to their potential anti-inflammatory and endothelial protective 4 effects. To-date published evidence from randomised control trials (RCTs) does not provide evidence 5 of benefit. We aimed to estimate the effect of oral administration of SGLT2i compared with usual care 6 or placebo in adults hospitalised with COVID-19
Effect of Thromboprophylaxis on Clinical Outcomes After COVID-19 Hospitalization
BACKGROUND: Patients hospitalized with COVID-19 have an increased incidence of thromboembolism. The role of extended thromboprophylaxis after hospital discharge is unclear.
OBJECTIVE: To determine whether anticoagulation is superior to placebo in reducing death and thromboembolic complications among patients discharged after COVID-19 hospitalization.
DESIGN: Prospective, randomized, double-blind, placebo-controlled clinical trial. (ClinicalTrials.gov: NCT04650087).
SETTING: Done during 2021 to 2022 among 127 U.S. hospitals.
PARTICIPANTS: Adults aged 18 years or older hospitalized with COVID-19 for 48 hours or more and ready for discharge, excluding those with a requirement for, or contraindication to, anticoagulation.
INTERVENTION: 2.5 mg of apixaban versus placebo twice daily for 30 days.
MEASUREMENTS: The primary efficacy end point was a 30-day composite of death, arterial thromboembolism, and venous thromboembolism. The primary safety end points were 30-day major bleeding and clinically relevant nonmajor bleeding.
RESULTS: Enrollment was terminated early, after 1217 participants were randomly assigned, because of a lower than anticipated event rate and a declining rate of COVID-19 hospitalizations. Median age was 54 years, 50.4% were women, 26.5% were Black, and 16.7% were Hispanic; 30.7% had a World Health Organization severity score of 5 or greater, and 11.0% had an International Medical Prevention Registry on Venous Thromboembolism risk prediction score of greater than 4. Incidence of the primary end point was 2.13% (95% CI, 1.14 to 3.62) in the apixaban group and 2.31% (CI, 1.27 to 3.84) in the placebo group. Major bleeding occurred in 2 (0.4%) and 1 (0.2%) and clinically relevant nonmajor bleeding occurred in 3 (0.6%) and 6 (1.1%) apixaban-treated and placebo-treated participants, respectively. By day 30, thirty-six (3.0%) participants were lost to follow-up, and 8.5% of apixaban and 11.9% of placebo participants permanently discontinued the study drug treatment.
LIMITATIONS: The introduction of SARS-CoV-2 vaccines decreased the risk for hospitalization and death. Study enrollment spanned the peaks of the Delta and Omicron variants in the United States, which influenced illness severity.
CONCLUSION: The incidence of death or thromboembolism was low in this cohort of patients discharged after hospitalization with COVID-19. Because of early enrollment termination, the results were imprecise and the study was inconclusive.
PRIMARY FUNDING SOURCE: National Institutes of Health
Heparin Dose Intensity and Organ Support-Free Days in Patients Hospitalized for COVID-19.
BACKGROUND
Clinical trials suggest that therapeutic-dose heparin may prevent critical illness and vascular complications due to COVID-19, but knowledge gaps exist regarding the efficacy of therapeutic heparin including its comparative effect relative to intermediate-dose anticoagulation.
OBJECTIVES
The authors performed 2 complementary secondary analyses of a completed randomized clinical trial: 1) a prespecified per-protocol analysis; and 2) an exploratory dose-based analysis to compare the effect of therapeutic-dose heparin with low- and intermediate-dose heparin.
METHODS
Patients who received initial anticoagulation dosed consistently with randomization were included. The primary outcome was organ support-free days (OSFDs), a combination of in-hospital death and days free of organ support through day 21.
RESULTS
Among 2,860 participants, 1,761 (92.8%) noncritically ill and 857 (89.1%) critically ill patients were treated per-protocol. Among noncritically ill per-protocol patients, the posterior probability that therapeutic-dose heparin improved OSFDs as compared with usual care was 99.3% (median adjusted OR: 1.36; 95% credible interval [CrI]: 1.07-1.74). Therapeutic heparin had a high posterior probability of efficacy relative to both low- (94.6%; adjusted OR: 1.26; 95% CrI: 0.95-1.64) and intermediate- (99.8%; adjusted OR: 1.80; 95% CrI: 1.22-2.62) dose thromboprophylaxis. Among critically ill per-protocol patients, the posterior probability that therapeutic heparin improved outcomes was low.
CONCLUSIONS
Among noncritically ill patients hospitalized for COVID-19 who were randomized to and initially received therapeutic-dose anticoagulation, heparin, compared with usual care, was associated with improved OSFDs, a combination of in-hospital death and days free of organ support. Therapeutic heparin appeared superior to both low- and intermediate-dose thromboprophylaxis
The development of HISPEC for Keck and MODHIS for TMT: science cases and predicted sensitivities
HISPEC is a new, high-resolution near-infrared spectrograph being designed
for the W.M. Keck II telescope. By offering single-shot, R=100,000 between 0.98
- 2.5 um, HISPEC will enable spectroscopy of transiting and non-transiting
exoplanets in close orbits, direct high-contrast detection and spectroscopy of
spatially separated substellar companions, and exoplanet dynamical mass and
orbit measurements using precision radial velocity monitoring calibrated with a
suite of state-of-the-art absolute and relative wavelength references. MODHIS
is the counterpart to HISPEC for the Thirty Meter Telescope and is being
developed in parallel with similar scientific goals. In this proceeding, we
provide a brief overview of the current design of both instruments, and the
requirements for the two spectrographs as guided by the scientific goals for
each. We then outline the current science case for HISPEC and MODHIS, with
focuses on the science enabled for exoplanet discovery and characterization. We
also provide updated sensitivity curves for both instruments, in terms of both
signal-to-noise ratio and predicted radial velocity precision.Comment: 25 pages, 9 figures. To appear in the Proceedings of SPIE: Techniques
and Instrumentation for Detection of Exoplanets XI, vol. 12680 (2023
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