Spectral evolution of GRB 060904A observed with Swift and Suzaku -- Possibility of Inefficient Electron Acceleration

We observed an X-ray afterglow of GRB 060904A with the Swift and Suzaku satellites. We found rapid spectral softening during both the prompt tail phase and the decline phase of an X-ray flare in the BAT and XRT data. The observed spectra were fit by power-law photon indices which rapidly changed from $\Gamma = 1.51^{+0.04}_{-0.03}$ to $\Gamma = 5.30^{+0.69}_{-0.59}$ within a few hundred seconds in the prompt tail. This is one of the steepest X-ray spectra ever observed, making it quite difficult to explain by simple electron acceleration and synchrotron radiation. Then, we applied an alternative spectral fitting using a broken power-law with exponential cutoff (BPEC) model. It is valid to consider the situation that the cutoff energy is equivalent to the synchrotron frequency of the maximum energy electrons in their energy distribution. Since the spectral cutoff appears in the soft X-ray band, we conclude the electron acceleration has been inefficient in the internal shocks of GRB 060904A. These cutoff spectra suddenly disappeared at the transition time from the prompt tail phase to the shallow decay one. After that, typical afterglow spectra with the photon indices of 2.0 are continuously and preciously monitored by both XRT and Suzaku/XIS up to 1 day since the burst trigger time. We could successfully trace the temporal history of two characteristic break energies (peak energy and cutoff energy) and they show the time dependence of $\propto t^{-3} \sim t^{-4}$ while the following afterglow spectra are quite stable. This fact indicates that the emitting material of prompt tail is due to completely different dynamics from the shallow decay component. Therefore we conclude the emission sites of two distinct phenomena obviously differ from each other.Comment: 19 pages, 9 figures, accepted for publication in PASJ (Suzaku 2nd Special Issue

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

BACKGROUND: During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study\u27s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines. METHODS: We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March-31 May 2020. The prior 1-year control period (1 March-31 May 2019) was obtained to account for seasonal variation. FINDINGS: There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI -24.3% to -20.7%, p\u3c0.0001). Embolisation of ruptured aneurysms declined with 1170-1035 procedures, respectively, representing an 11.5% (95%CI -13.5% to -9.8%, p=0.002) relative drop. Subgroup analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations, a 24.9% relative decline (95% CI -28.0% to -22.1%, p\u3c0.0001). A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1% (95% CI 32.3% to 50.6%, p=0.008) despite a decrease in SAH admissions in this tertile. INTERPRETATION: There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction

Use of Ranibizumab for evaluating focal laser combination therapy for refractory diabetic macular edema patients: an exploratory study on the RELAND trials

Abstract Anti-vascular endothelial growth factor (VEGF) therapy is the first-line treatment for diabetic macular edema (DME), but is less effective in some patients. We conducted a prospective study to determine whether laser combination therapy with anti-VEGF was more effective than Ranibizumab monotherapy in anti-VEGF-resistant DME patients. There was no significant difference in the improvement of the best-corrected visual acuity (BCVA) between the laser combination therapy and Ranibizumab monotherapy groups (3.2 letters and -7.5 letters, p = 0.165). BCVA did not significantly change between visits 1 and 7 (the laser combination group, 64.3 letters 70.3 letters, respectively, p = 0.537; the Ranibizumab monotherapy group, 72.3 letters and 64.8 letters, respectively, p = 0.554), with no significant improvements in central foveal retinal thickness (the laser combination therapy group, 9.3%: the Ranibizumab monotherapy groups, − 7.3%; p = 0.926). There was no significant difference in the number of Ranibizumab intravitreal therapy (IVT) sessions between the groups (laser combination therapy, 5.2; ranibizumab monotherapy, 6.0; p = 0.237). This study did not show that laser combination therapy was significantly more effective for anti-VEGF-resistant DME than anti-VEGF monotherapy alone. Therefore, for anti-VEGF-resistant DME, alternative therapeutic approaches beyond combined laser therapy may be considered

Ventricular arrhythmia events in heart failure patients with cardiac resynchronization therapy with or without a defibrillator for primary prevention

Abstract Background It is uncertain whether cardiac resynchronization therapy with a defibrillator (CRT‐D) provides better survival benefits than a CRT‐pacemaker (CRT‐P) in heart failure patients with a reduced ejection fraction (≦35%, HFrEF) treated with contemporary HF therapy. Methods We retrospectively analyzed the ventricular arrhythmia (VAs; sustained ventricular tachycardia/fibrillation) events in HFrEF patients who underwent CRT without a prior history of VAs or aborted sudden cardiac death before the CRT implantation. Between January/2010 and December/2020, a CRT device was implanted in 79 HFrEF patients (mean age: 69 ± 12 years, male: 57, ischemic cardiomyopathy: 16). CRT‐D and CRT‐P devices were implanted in 50 and 29 patients, respectively, at each physician's discretion. CRT‐Ds were indicated in younger patients than were CRT‐Ps (66 ± 12 vs. 73 ± 12 years, p = 0.03), but the gender distribution did not differ (female, 24% [12 of 50] vs. 35% [10 of 29], p = 0.44). The VA events during a median follow‐up of 3.5‐years (interquartile range [IQR]:1.6–5.5) and their predictors were analyzed. Results VA events occurred in 9 patients with CRT‐Ds (18%) and one with a CRT‐P (3%, p = 0.08). The VA event rate was significantly lower in patients without a prior non‐sustained ventricular tachycardia (NSVT: ≥3 beats; rate, ≥120 bpm; lasting <30 s, HR 0.05; 95% CI 0.01–0.30; p < 0.01) and females (HR 0.11; 95% CI 0.01–0.93; p = 0.04). Of note, no female patients without a prior history of NSVT experienced VA events. Conclusion HFrEF CRT candidates without a prior history of NSVT and females may obtain less benefit from a primary preventive defibrillator indication

Electrophysiological and Pathological Impact of Medium-Dose External Carbon Ion and Proton Beam Radiation on the Left Ventricle in an Animal Model

Background Medium-dose (25 gray) x-ray radiation therapy has recently been performed on patients with refractory ventricular tachyarrhythmias. Unlike x-ray, carbon ion and proton beam radiation can deliver most of their energy to the target tissues. This study investigated the electrophysiological and pathological changes caused by medium-dose carbon ion and proton beam radiation in the left ventricle (LV). Methods and Results External beam radiation in the whole LV was performed in 32 rabbits. A total of 9 rabbits were not irradiated (control). At the 3-month or 6-month follow-up, the animals underwent an open-chest electrophysiological study and were euthanized for histological analyses. No acute death occurred. Significant LV dysfunction was not seen. The surface ECG revealed a significant reduction in the P and QRS wave voltages in the radiation groups. The electrophysiological study showed that the local conduction times in each LV site were significantly longer and that the local LV bipolar voltages were significantly lower in the radiation groups than in the control rabbits. Histologically, apoptosis, fibrotic changes, and a decrease in the expression of the connexin 43 protein were seen in the LV myocardium. These changes were obvious at 3 months, and the effects were sustained 6 months after radiation. No histological changes were seen in the coronary artery and esophagus, but partial radiation pneumonitis was observed. Conclusions Medium-dose carbon ion and proton beam radiation in the whole LV resulted in a significant electrophysiological disturbance and pathological changes in the myocardium. Radiation of the arrhythmogenic substrate would modify the electrical status and potentially induce the antiarrhythmic effect

Nationwide Trends in Reperfusion Therapy and Outcomes of Acute Ischemic Stroke According to Severity: The Japan Stroke Data Bank

Background It is unclear whether all patient subgroups with acute ischemic stroke have benefited from advances in reperfusion therapy. We investigated long‐term trends of reperfusion therapy and outcomes according to the stroke severity. Methods Patients with acute ischemic stroke registered in the prospective nationwide hospital‐based registry between 2000 and 2020 were examined. Baseline National Institutes of Health Stroke Scale (NIHSS) score ≥10 and ≤5 was considered to indicate possible large vessel occlusions and minor deficits, respectively. Secular changes were assessed per 5‐year cohorts (2000–2005, 2006–2010, 2011–2015, 2016–2020). Outcomes included favorable outcome (modified Rankin scale score 0–2 at discharge). Results Of 127 741 patients, NIHSS score was ≥10 in 31 747 patients (24.9%), 6–9 in 17 083 patients (13.4%), and ≤5 in 78 911 patients (61.8%). In patients with NIHSS score ≥10, intravenous thrombolysis frequency increased from 1.6% to 26.5% between the 2000 to 2005 and 2016 to 2020 cohorts; endovascular therapy frequency increased from 2.0% to 29.8%. Favorable outcomes increased over time (adjusted odds ratio per 1‐cohort, 1.254 [95% CI, 1.204–1.306]). In patients with NIHSS score 6–9, intravenous thrombolysis frequency increased from 0.5% to 16.4%, and endovascular therapy frequency increased from 1.1% to 9.0%. Favorable outcomes did not change over time (1.005 [0.966–1.046]). In patients with NIHSS score ≤5, intravenous thrombolysis frequency increased from 0.2% to 5.1%, and endovascular therapy frequency increased from 0.7% to 2.8%. Favorable outcomes decreased over time (0.954 [0.931–0.978]). Conclusions Use of reperfusion therapy has increased, particularly in patients with NIHSS score ≥10. Favorable outcomes significantly increased over time in patients with NIHSS score ≥10 but decreased in those with NIHSS score ≤5

Atrial Fibrillation Detection and Ischemic Stroke Recurrence in Cryptogenic Stroke: A Retrospective, Multicenter, Observational Study

Background Atrial fibrillation (AF) is known to be a strong risk factor for stroke. However, the risk of stroke recurrence in patients with cryptogenic stroke with AF detected after stroke by an insertable cardiac monitor (ICM) is not well known. We sought to evaluate the risk of ischemic stroke recurrence in patients with cryptogenic stroke with and without ICM‐detected AF. Methods and Results We retrospectively reviewed patients with cryptogenic stroke who underwent ICM implantation at 8 stroke centers in Japan. Cox regression models were developed using landmark analysis and time‐dependent analysis. We set the target sample size at 300 patients based on our estimate of the annualized incidence of ischemic stroke recurrence to be 3% in patients without AF detection and 9% in patients with AF detection. Of the 370 patients, 121 were found to have AF, and 110 received anticoagulation therapy after AF detection. The incidence of ischemic stroke recurrence was 4.0% in 249 patients without AF detection and 5.8% in 121 patients with AF detection (P=0.45). In a landmark analysis, the risk of ischemic stroke recurrence was not higher in patients with AF detected ≤90 days than in those without (hazard ratio, 1.47 [95% CI, 0.41–5.28]). In a time‐dependent analysis, the risk of ischemic stroke recurrence did not increase after AF detection (hazard ratio, 1.77 [95% CI, 0.70–4.47]). Conclusions The risk of ischemic stroke recurrence in patients with cryptogenic stroke with ICM‐detected AF, 90% of whom were subsequently anticoagulated, was not higher than in those without ICM‐detected AF