170 research outputs found

    MAXI GSC observations of a spectral state transition in the black hole candidate XTE J1752-223

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    We present the first results on the black hole candidate XTE J1752-223 from the Gas Slit Camera (GSC) on-board the Monitor of All-sky X-ray Image (MAXI) on the International Space Station. Including the onset of the outburst reported by the Proportional Counter Array on-board the Rossi X-ray Timing Explorer on 2009 October 23, the MAXI/GSC has been monitoring this source approximately 10 times per day with a high sensitivity in the 2-20 keV band. XTE J1752-223 was initially in the low/hard state during the first 3 months. An anti-correlated behavior between the 2-4 keV and 4-20 keV bands were observed around January 20, 2010, indicating that the source exhibited the spectral transition to the high/soft state. A transient radio jet may have been ejected when the source was in the intermediate state where the spectrum was roughly explained by a power-law with a photon index of 2.5-3.0. The unusually long period in the initial low/hard state implies a slow variation in the mass accretion rate, and the dramatic soft X-ray increase may be explained by a sudden appearance of the accretion disk component with a relatively low innermost temperature (0.4-0.7 keV). Such a low temperature might suggest that the maximum accretion rate was just above the critical gas evaporation rate required for the state transition.Comment: Publication of Astronomical Society of Japan Vol.62, No.5 (2010) [in print

    Bright X-ray flares from the BL Lac object Mrk 421, detected with MAXI in 2010 January and February

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    Strong X-ray flares from the blazar Mrk 421 were detected in 2010 January and February through the 7 month monitoring with the MAXI GSC. The maximum 2 -- 10 keV flux in the January and February flares was measured as 120 +- 10 mCrab and 164 +- 17 mCrab respectively; the latter is the highest among those reported from the object. A comparison of the MAXI and Swift BAT data suggests a convex X-ray spectrum with an approximated photon index of about 2. This spectrum is consistent with a picture that MAXI is observing near the synchrotron peak frequency. The source exhibited a spectral variation during these flares, slightly different from those in the previous observations, in which the positive correlation between the flux and hardness was widely reported. By equating the halving decay timescale in the January flare, td2.5×104t_{\rm d} \sim 2.5 \times 10^{4} s, to the synchrotron cooling time, the magnetic field was evaluated as B = 0.045 G (δ/10)1/3(\delta/10)^{-1/3}, where δ\delta is the jet beaming factor. Assuming that the light crossing time of the emission region is shorter than the doubling rise time, tr2×104t_{\rm r} \lesssim 2 \times 10^{4} s, the region size was roughly estimated as R<6×1015 R < 6 \times 10^{15} cm (δ/10)(\delta/10). These are consistent with the values previously reported. For the February flare, the rise time, tr<1.3×105t_{\rm r} < 1.3 \times 10^{5} s, gives a loose upper limit on the size as R<4×1016 R < 4 \times 10^{16} cm (δ/10)(\delta/10), although the longer decay time td1.4×105t_{\rm d} \sim 1.4 \times 10^{5} s, indicates B = 0.015 G (δ/10)1/3(\delta/10)^{-1/3}, which is weaker than the previous results. This could be reconciled by invoking a scenario that this flare is a superposition of unresolved events with a shorter timescale.Comment: 14 pages, 4 figures, accepted for PASJ (Vol. 62 No. 6

    Association between Body Mass Index and Prognosis of Patients Hospitalized With Heart Failure

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    The prognostic implications of very low body mass index (BMI) values remain unclear in patients with acute decompensated heart failure (ADHF). This study aimed to investigate the prognostic impact of BMI classification based on the World Health Organization criteria in patients with ADHF. Among 3509 patients with ADHF and available BMI data at discharge in 19 participating hospitals in Japan between October 2014 and March 2016, the study population was divided into five groups; (1) Severely underweight: BMI < 16 kg/m², (2) Underweight: BMI ≥ 16 kg/m² and < 18.5 kg/m², (3) Normal weight: BMI ≥ 18.5 kg/m² and < 25 kg/m², (4) Overweight: BMI ≥ 25 kg/m² and < 30 kg/m² (5) Obese: BMI ≥ 30 kg/m². The primary outcome measure was all-cause death. The median follow-up duration was 471 days, with 96.4% follow up at 1-year. The cumulative 1-year incidence of all-cause death was higher in underweight groups, and lower in overweight groups (Severely underweight: 36.3%, Underweight: 23.9%, Normal weight: 14.4%, Overweight: 7.9%, and Obese: 9.0%, P < 0.001). After adjusting confounders, the excess mortality risk remained significant in the severely underweight group (HR, 2.32; 95%CI, 1.83–2.94; P < 0.001), and in the underweight group (HR, 1.31; 95%CI, 1.08–1.59; P = 0.005) relative to the normal weight group, while the lower mortality risk was no longer significant in the overweight group (HR, 0.82; 95%CI, 0.62–1.10; P = 0.18) and in the obese group (HR, 1.09; 95%CI, 0.65–1.85; P = 0.74). Very low BMI was associated with a higher risk for one-year mortality after discharge in patients with ADHF

    Association between changes in loop diuretic dose and outcomes in acute heart failure

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    AIMS: Little is known about the association between the starting of or dose changes in loop diuretics during acute heart failure (AHF) hospitalization and post-discharge outcomes. We investigated the clinical impact of starting loop diuretics and changing the loop diuretics dose during hospitalization on post-discharge outcomes. METHODS AND RESULTS: From the Kyoto Congestive Heart Failure registry, 3665 consecutive patients hospitalized for HF and discharged alive were included in this study. We analysed 1906 patients without loop diuretics on admission and were discharged alive and 1759 patients who received loop diuretics on admission and were discharged alive. The primary outcome measure was all-cause death. Of the 1906 patients without loop diuretics on admission, 1366 (71.7%) patients started loop diuretics during the index AHF hospitalization. Starting loop diuretics was not associated with lower post-discharge mortality [adjusted hazard ratio (HR) 0.92, 95% confidence interval (CI) 0.68-1.25]. Of the 1759 patients who received loop diuretics on admission, loop diuretic dose was decreased in 23.8%, unchanged in 44.6%, and increased in 31.6% of the patients. Changes in the dose at discharge compared with no change in dose were not associated with lower risk of post-discharge mortality (decrease relative to no change: adjusted HR 0.98, 95% CI 0.76-1.28; increase relative to no change: adjusted HR 1.00, 95% CI 0.78-1.27). Compared with no loop diuretics at discharge, a loop diuretics dose of ≥80 mg at discharge was associated with higher post-discharge mortality risk. CONCLUSIONS: In patients with AHF, we found no association between the starting of loop diuretics and post-discharge outcomes and between dose changes and post-discharge outcomes

    Newly Diagnosed Infection After Admission for Acute Heart Failure: From the KCHF Registry

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    [Background] No studies have explored the association between newly diagnosed infections after admission and clinical outcomes in patients with acute heart failure. We aimed to explore the factors associated with newly diagnosed infection after admission for acute heart failure, and its association with in‐hospital and post‐discharge clinical outcomes. [Methods and Results] Among 4056 patients enrolled in the Kyoto Congestive Heart Failure registry, 2399 patients without any obvious infectious disease upon admission were analyzed. The major in‐hospital and post‐discharge outcome measures were all‐cause deaths. There were 215 patients (9.0%) with newly diagnosed infections during hospitalization, and 2184 patients (91.0%) without infection during hospitalization. The factors independently associated with a newly diagnosed infection were age ≥80 years, acute coronary syndrome, non‐ambulatory status, hyponatremia, anemia, intubation, and patients who were not on loop diuretics as outpatients. The newly diagnosed infection group was associated with a higher incidence of in‐hospital mortality (16.3% and 3.2%, P<0.001) and excess adjusted risk of in‐hospital mortality (odds ratio, 6.07 [95% CI, 3.61–10.19], P<0.001) compared with the non‐infection group. The newly diagnosed infection group was also associated with a higher 1‐year incidence of post‐discharge mortality (19.3% in the newly diagnosed infection group and 13.6% in the non‐infection group, P<0.001) and excess adjusted risk of post‐discharge mortality (hazard ratio, 1.49 [95% CI, 1.08–2.07], P=0.02) compared with the non‐infection group. [Conclusions] Elderly patients with multiple comorbidities were associated with the development of newly diagnosed infections after admission for acute heart failure. Newly diagnosed infections after admission were associated with higher in‐hospital and post‐discharge mortality in patients with acute heart failure

    Coronary angiography in patients with acute heart failure: from the KCHF registry

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    [Aims] Little is known about the characteristics and outcomes of patients who undergo coronary angiography during heart failure (HF) hospitalization, as well as those with coronary stenosis, and those who underwent coronary revascularization. [Methods and results] We analysed 2163 patients who were hospitalized for HF without acute coronary syndrome or prior HF hospitalization. We compared patient characteristics and 1 year clinical outcomes according to (i) patients with versus without coronary angiography, (ii) patients with versus without coronary stenosis, and (iii) patients with versus without coronary revascularization. The primary outcome measure was the composite of all-cause death or HF hospitalization. Coronary angiography was performed in 37.0% of patients. In the multivariable logistic regression analysis, factors independently associated with coronary angiography were age < 80 years [adjusted odds ratio (OR) = 1.76, 95% confidence interval (CI) = 1.41–2.20, P < 0.001], men (adjusted OR = 1.28, 95% CI = 1.03–1.59, P = 0.02), diabetes (adjusted OR = 1.27, 95% CI = 1.02–1.60, P = 0.04), no atrial fibrillation or flutter (adjusted OR = 1.45, 95% CI = 1.17–1.82, P < 0.001), no prior device implantation (adjusted OR = 1.81, 95% CI = 1.13–2.91, P = 0.01), current smoking (adjusted OR = 1.40, 95% CI = 1.05–1.87, P = 0.02), no cognitive dysfunction (adjusted OR = 1.90, 95% CI = 1.34–2.69, P < 0.001), ambulatory status (adjusted OR = 2.89, 95% CI = 2.03–4.10, P < 0.001), HF with reduced ejection fraction (adjusted OR = 1.55, 95% CI = 1.24–1.93, P < 0.001), estimated glomerular filtration rate ≥ 30 mL/min/1.73 m2 (adjusted OR = 1.93, 95% CI = 1.45–2.58, P < 0.001), no anaemia (adjusted OR = 1.27, 95% CI = 1.02–1.59, P = 0.04), and no prescription of β-blockers prior to admission (adjusted OR = 1.32, 95% CI = 1.03–1.68, P = 0.03). Patients who underwent coronary angiography had a lower risk of the primary outcome [adjusted hazard ratio (HR) = 0.70, 95% CI = 0.58–0.85, P < 0.001]. Among the patients who underwent coronary angiography, those with coronary stenosis (38.9%) did not have lower risk of the primary outcome measure than those without coronary stenosis (adjusted HR = 0.93, 95% CI = 0.65–1.32, P = 0.68). Among the patients with coronary stenosis, those with coronary revascularization (54.3%) did not have higher risk of the primary outcome measure than those without coronary revascularization (adjusted HR = 1.36, 95% CI = 0.84–2.21, P = 0.22). [Conclusions] In patients with acute HF, patients who underwent coronary angiography had a lower risk of clinical outcomes and were significantly different from those who did not undergo coronary angiography

    A comparison between hospital follow‐up and collaborative follow‐up in patients with acute heart failure

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    AIMS: There are no previous studies focusing on collaborative follow-ups between hospitals and clinics for patients discharged after acute heart failure (AHF) in Japan. The purpose of this study was to determine the status of collaboration between hospitals and clinics for patients with AHF in Japan and to compare patient characteristics and clinical outcomes using a large Japanese observational database. METHODS AND RESULTS: Of 4056 consecutive patients hospitalized for AHF in the Kyoto Congestive Heart Failure registry, we analysed 2862 patients discharged to go home, who were divided into 1674 patients (58.5%) followed up at hospitals with index hospitalization (hospital follow-up group) and 1188 (41.5%) followed up in a collaborative fashion with clinics or other general hospitals (collaborative follow-up group). The primary outcome was a composite of all-cause death or heart failure (HF) hospitalization within 1 year after discharge. Previous hospitalization for HF and length of hospital stay longer than 15 days were associated with hospital follow-up. Conversely, ≥80 years of age, hypertension, and cognitive dysfunction were associated with collaborative follow-up. The cumulative 1-year incidence of the primary outcome, all cause death, and cardiovascular death were similar between the hospital and collaborative follow-up groups (31.6% vs. 29.6%, P = 0.51, 13.1% vs, 13.9%, P = 0.35, 8.4% vs. 8.2%, P = 0.96). Even after adjusting for confounders, the difference in risk for patients in the hospital follow-up group relative to those in the collaborative follow-up group remained insignificant for the primary outcome, all-cause death, and cardiovascular death (HR: 1.11, 95% CI: 0.97-1.27, P = 0.14, HR: 1.10, 95% CI: 0.91-1.33, P = 0.33, HR: 0.96, 95% CI: 0.87-1.05, P = 0.33). The cumulative 1-year incidence of HF hospitalization was higher in the hospital follow-up group than in the collaborative follow-up group (25.5% vs. 21.3%, P = 0.02). The risk of HF hospitalization was higher in the hospital follow-up group than in the collaborative follow-up group (HR: 1.19, 95% CI: 1.01-1.39, P = 0.04). CONCLUSIONS: In patients hospitalized for AHF, 41.5% received collaborative follow-up after discharge. The risk of HF hospitalization was higher in the hospital follow-up group than in the collaborative follow-up, although risk of the primary outcome, all-cause death, and cardiovascular death were similar between groups

    Efficacy and Safety of Intravitreal Aflibercept Treat-and-Extend Regimens in Exudative Age-Related Macular Degeneration: 52- and 96-Week Findings from ALTAIR : A Randomized Controlled Trial.

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    PURPOSE:To evaluate efficacy and safety of intravitreal injections of aflibercept (IVT-AFL) treat-and-extend (T&E) dosing regimens in treatment-naïve patients with exudative age-related macular degeneration (AMD).METHODS:Adults aged at least 50 years old with exudative AMD and best-corrected visual acuity (BCVA) of 73-25 Early Treatment Diabetic Retinopathy Study (ETDRS) letters were included. Patients received three monthly doses of IVT-AFL 2 mg. At week 16, patients were randomized 1:1 to IVT-AFL T&E with either 2- or 4-week adjustments. The primary endpoint was mean change in BCVA from baseline to week 52. Outcomes were assessed at weeks 52 and 96.RESULTS:Baseline characteristics were comparable between the groups (n = 123 each). Over 52 weeks, mean number of injections was 7.2 and 6.9 and mean last injection interval was 10.7 and 11.8 weeks, for the 2- and 4-week groups, respectively. From baseline, mean change in BCVA was + 9.0 and + 8.4 letters (week 52) and + 7.6 and + 6.1 letters (week 96); mean change in central retinal thickness was - 134.4 µm and - 126.1 µm (week 52) and - 130.5 µm and - 125.3 µm (week 96). Last injection interval before week 52 was at least 12 weeks in 42.3% and 49.6% of patients and 56.9% and 60.2% before week 96. Over 96 weeks, mean number of injections was 10.4 (both groups). The safety profile of IVT-AFL was consistent with previous reports.CONCLUSIONS:IVT-AFL administered using two different T&E regimens for treatment-naïve exudative AMD improved functional and anatomic outcomes at week 52 and outcomes were maintained to week 96. Outcomes were similar between the 2- and 4-week groups.TRIAL REGISTRATION:ClinicalTrials.gov identifier, NCT02305238

    Demographics, practice patterns and long-term outcomes of patients with non–ST-segment elevation acute coronary syndrome in the past two decades: the CREDO-Kyoto Cohort-2 and Cohort-3

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    OBJECTIVES: To evaluate patient characteristics and long-term outcomes in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS) in the past two decades. DESIGN: Multicenter retrospective study. SETTING: The Coronary REvascularization Demonstrating Outcome Study in Kyoto (CREDO-Kyoto) percutaneous coronary intervention (PCI)/coronary artery bypass grafting (CABG) Registry Cohort-2 (2005-2007) and Cohort-3 (2011-2013). PARTICIPANTS: 3254 patients with NSTEACS who underwent first coronary revascularisation. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was all-cause death. The secondary outcomes were cardiovascular death, cardiac death, sudden cardiac death, non-cardiovascular death, non-cardiac death, myocardial infarction, definite stent thrombosis, stroke, hospitalisation for heart failure, major bleeding, any coronary revascularisation and target vessel revascularisation. RESULTS: Patients in Cohort-3 were older and more often had heart failure at admission than those in Cohort-2. The prevalence of PCI, emergency procedure and guideline-directed medical therapy was higher in Cohort-3 than in Cohort-2. In patients who received PCI, the prevalence of transradial approach, drug-eluting stent use and intravascular ultrasound use was higher in Cohort-3 than in Cohort-2. There was no change in 3-year adjusted mortality risk from Cohort-2 to Cohort-3 (HR 1.00, 95% CI 0.83 to 1.22, p=0.97). Patients in Cohort-3 compared with those in Cohort-2 were associated with lower adjusted risks for stroke (HR 0.65, 95% CI 0.46 to 0.92, p=0.02) and any coronary revascularisation (HR 0.76, 95%CI 0.66 to 0.87, p<0.001), but with higher risk for major bleeding (HR 1.25, 95% CI 1.06 to 1.47, p=0.008). The unadjusted risk for definite stent thrombosis was lower in Cohort-3 than in Cohort 2 (HR 0.29, 95% CI 0.11 to 0.67, p=0.003). CONCLUSIONS: In the past two decades, we did not find improvement for mortality in patients with NSTEACS. We observed a reduction in the risks for definite stent thrombosis, stroke and any coronary revascularisation, but an increase in the risk for major bleeding
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