The MeV region of antineutrino energy is of special interest for physics research and for monitoring nuclear nonproliferation. Whereas liquid scintillation detectors are typically used to detect the ...Inverse Beta Decay (IBD), it has recently been proposed to detect it with a liquid-organic Time Projection Chamber, which could allow a full reconstruction of the particle tracks of the IBD final state. We present the first simulation-based statistical analysis of the expected signatures. Their unequivocal signature could enable a background-minimized detection of electron antineutrinos using information on energy, location and direction of all final state particles. We show that the positron track reflects the antineutrino’s vertex. It can also be used to determine the initial neutrino energy. In addition, we investigate the possibility to reconstruct the antineutrino direction on an event-by-event basis by the energy deposition of the neutron-induced proton recoils. Our simulations indicate that this could be a promising approach which should be further studied through experiments with a detector prototype.
Recently a new effervescent acetylsalicylic acid (ASA) tablet with high buffering capacity has been developed. In this double-blind, 3-arm, multicenter, parallel-group study, 433 patients were ...treated either with 1,000 mg effervescent ASA or 50 mg encapsulated sumatriptan or placebo. The primary endpoint was the percentage of patients with complete remission of the 3 accompanying symptoms nausea, photophobia and phonophobia within 2 h after intake of the study drug. 43.8% of patients treated with ASA, 43.7% of patients treated with sumatriptan and 30.9% of patients treated with placebo showed complete remission of all 3 accompanying symptoms (p < 0.05 for ASA and sumatriptan vs. placebo). Both active treatments were superior to placebo regarding the individual symptoms photophobia and phonophobia, but not for nausea. The percentage of patients with reduction in headache severity from moderate or severe to mild or no pain (secondary objective) was 49.3% for ASA, 48.8% for sumatriptan and 32.9% for placebo. All active treatments were superior to placebo (p < 0.05). 25.3, 24.4 and 14.5% of patients treated with ASA, sumatriptan or placebo were pain free at 2 h. Drug-related adverse events were reported in 3.9, 4.7 and 6.7% of patients treated with placebo, ASA or sumatriptan. The study showed that administration of effervescent ASA leads to remission of the migraine symptoms nausea, photophobia and phonophobia, reduces migraine headache and is comparable to sumatriptan.
We report an observation of ultra-high energy (UHE) gamma rays from the Galactic Center region, using seven years of data collected by the High-Altitude Water Cherenkov (HAWC) Observatory. The HAWC ...data are best described as a point-like source (HAWC J1746-2856) with a power-law spectrum (\(\mathrm{d}N/\mathrm{d}E=\phi(E/26 \,\text{TeV})^{\gamma}\)), where \(\gamma=-2.88 \pm 0.15_{\text{stat}} - 0.1_{\text{sys}} \) and \(\phi=1.5 \times 10^{-15}\) (TeV cm\(^{2}\)s)\(^{-1}\) \(\pm\, 0.3_{\text{stat}}\,^{+0.08_{\text{sys}}}_{-0.13_{\text{sys}}}\) extending from 6 to 114 TeV. We find no evidence of a spectral cutoff up to \(100\) TeV using HAWC data. Two known point-like gamma-ray sources are spatially coincident with the HAWC gamma-ray excess: Sgr A\(^{*}\) (HESS J1745-290) and the Arc (HESS J1746-285). We subtract the known flux contribution of these point sources from the measured flux of HAWC J1746-2856 to exclude their contamination and show that the excess observed by HAWC remains significant (\(>\)5\(\sigma\)) with the spectrum extending to \(>\)100 TeV. Our result supports that these detected UHE gamma rays can originate via hadronic interaction of PeV cosmic-ray protons with the dense ambient gas and confirms the presence of a proton PeVatron at the Galactic Center.
The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory located on the side of the Sierra Negra volcano in Mexico, has been fully operational since 2015. The HAWC collaboration has recently ...significantly improved their extensive-air-shower reconstruction algorithms, which has notably advanced the observatory performance. The energy resolution for primary gamma rays with energies below 1~TeV was improved by including a noise-suppression algorithm. Corrections have also been made to systematic errors in direction fitting related to the detector and shower plane inclinations, \(\mathcal{O}(0.1^{\circ})\) biases in highly inclined showers, as well as enhancements to the core reconstruction. The angular resolution for gamma rays approaching the HAWC array from large zenith angles (\(> 37^{\circ}\)) has improved by a factor of four at the highest energies (\(> 70\)~TeV) as compared to previous reconstructions. The inclusion of a lateral distribution function fit to the extensive air shower footprint on the array to separate gamma-ray primaries from cosmic-ray ones, based on the resulting \(\chi^{2}\) values, improved the background rejection performance at all inclinations. At large zenith angles, the improvement in significance is a factor of four compared to previous HAWC publications. These enhancements have been verified by observing the Crab Nebula, which is an overhead source for the HAWC Observatory. We show that the sensitivity to Crab-like point sources (\(E^{-2.63}\)) with locations overhead to 30\(^{\circ}\) zenith is comparable or less than 10\% of the Crab Nebula's flux between 2 and 50~TeV. Thanks to these improvements, HAWC can now detect more sources, including the Galactic Center.
Abstract
Background
Various randomized multicenter studies have shown that percutaneous left atrial appendage closure (LAAC) is not inferior in stroke prevention compared to vitamin K antagonists ...(VKA) and can be performed safely and effectively.
Aims
The prospective multicenter ORIGINAL registry in the Free State of Saxony (saxOnian RegIstry analyzinG and followINg left atrial Appendage cLosure) investigated the efficiency and safety of LAAC with Watchman or Amulet device in a real word setting. A special focus was put on the influence of LAAC frequency on periprocedural efficiency and safety.
Methods and results
The total of 482 consecutive patients (Abbott Amulet N = 93 and Boston Scientific Watchman N = 389) were included in the periinterventional analyses. After 6 weeks, 353 patients completed the first follow-up including transoesophageal echocardiography (TEE) (73.2%). Successful LAAC could be performed in more than 94%. The complication rate does not significantly differ between device types (
p
= 0.92) according to Fischer test and comprised 2.2% in the Amulet and 2.3% in the Watchman group. The kind of device and the frequency of LAAC per study center had no influence on the success and complication rates. Device related thrombus could be revealed more frequently in the Watchman group (4.5%) than in the Amulet group (1.4%) but this difference is still not significant in Fisher test (
p
= 0.14). Same conclusion can be made about residual leakage 1.1% versus 0% not significant in Fisher test (
p
= 0.26). Dual antiplatelet therapy followed the intervention in 64% and 22% of patients were discharged under a combination of an anticoagulant (VKA/DOAC/Heparin) and one antiplatelet agent.
Conclusions
The ORIGINAL registry supports the thesis from large, randomized trials that LAAC can be performed with a very high procedural success rate in the everyday clinical routine irrespective of the used LAA device (Watchman or Amulet). The postprocedural antithrombotic strategy differs widely among the participating centers.
Trial registration
Name of the registry: "saxOnian RegIstry analyzinG and followINg left atrial Appendage cLosure", Trial registration number: DRKS00023803; Date of registration: 15/12/2020 'Retrospectively registered'; URL of trial registry record:
https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00023803
.
Abstract
Aims
Left atrial appendage occlusion (LAAO) is a therapeutic option for patients with non-valvular atrial fibrillation (NVAF) and high risk of bleeding. This study reports outcomes of ...patients enrolled in the prospective multicentre, investigator initiated real life registry in the Free State of Saxony (saxOnian RegIstry analyzinG and followINg left atrial Appendage cLosure).
Methods and results
Data of all consecutive 521 patients (64.7% adult males, 35.3% adult females, mean age: 75.1 (SD 7.9) years with non-valvular atrial fibrillation undergoing interventional left atrial appendage occlusion procedure in the ORIGINAL prospective registry were analysed. The CHA2DS2-VASc and HAS-BLED scores were 4.3 (SD 1.5) and 3.7 (SD 1.1), respectively. 78.9% of the patients had a history of bleeding. 89.3% of the patients were considered as non-eligible for long term oral anticoagulation. A left atrial appendage occlusion device was successfully implanted in 97.5% of cases. A mean follow-up of 463 days could be reached in 386 patients. Among these, the distribution of the follow-up length reached was as follows: 1 year 205, 2 years 118, 3 years 65 and 4 years 17 patients. In the follow-up the annual frequency of stroke was very low (0.4%), which resulted in the 4.98% absolute risk reduction in the amount of thromboembolic strokes, which would have been expected according to the calculated CHA2DS2-VASc score in the hypothetic group not receiving any anticoagulant therapy. The occurrence of major and minor bleeding in the follow-up was 1.55% and 3.37% respectively.
Conclusions
In this prospective multicentre study we included the patients who are at high risk of stroke and bleeding. The annual ischemic stroke rate was 0.4%, the LAA could be sealed in 97.5%. Six months after the LAA closure only 3.63% of all patients were further on treated using oral anticoagulation. Considering the stroke reduction rates, the implantation of an LAAO device proves to be effective and safe in the clinical routine in the studied population.
Acknowledgement/Funding
None
Abstract
Background
Oral anticoagulation for prophylaxis of central and peripheral embolisation is limited in its use in patients with atrial fibrillation (AF) and bleeding events. As an alternative ...to anticoagulation, the interventional closure of the left atrial appendage (LAAO) is available. A common clinical dilemma is the treatment of patients with potential peri-device leakage following LAA occlusion. The specific definition of the severity of the leak and the long-term clinical implications have not yet been sufficiently investigated.
Methods
The multi-centre ORIGINAL registry was initiated 2014. The aim of this registry is to analyze the safety and efficacy of the procedure in patients with a high risk of bleeding in everyday clinical practice and to evaluate hemorrhagic and thromboemb. events in the long term follow-up. Patients with an indication for LAA occl. were included in the registry after informed consent. The impl., follow-up and anticoagulation regimens are performed according to the standard of the participating centers. 521 patients with AF underwent an implantation of an LAA closure device between Jul. 2014 and Nov. 2018. A mean follow-up of 463 days could be reached in 386 patients.
Results
The periprocedural complication rate was 3.8% of which 5 patients experienced pericardial effusion (successful treatment with pericardial puncture or surgical), 2 patients had periprocedural stroke and 1 patient suffered from air embolism. In 27 patients a peri-device flow due to incomplete occlusion was detected by TEE (5.4% of the implantations). The size ranged between 1 and 8 mm (mean 2.28 mm (SD=2.11)). The eccentricity index (EI) of the LAA in these patients was 1.22 (SD 0.17), and thus the LAA rather oval, while those LAA without leakage tend to be more circular (EI 1.08 with SD=0.17). 2 of the patients with leakage (7.4%) experienced stroke or peripheral embolism, respectively. The annual risk for stroke/TIA/peripheral embolism of these patients was 5.84%, the annual risk of the patients without leakage was 2.04%. Patients with a leakage >6 mm were treated with rivaroxaban in full therapeutic dosage. One patient underwent an additional procedure.
Conclusion
The evaluation and management of para-device leakage after an interventional LAA occlusion represents a challenge. Currently, limited data are available on the optimal strategy. Those data indicate that residual peri-device flow into the LAA after percutaneous closure with the Watchman device represents no cause for alarm. However, our data suggest, that patients with peridevice leak might be at a higher risk of thromboembolic events. Furthermore, it could be shown, that these patients had rather oval ostium of the LAA, while those LAA without leakage tend to be more circular. This implicates the importance of advanced imaging methods, such as 3D-TEE, which are capable to precisely determine the size of the LAA and the degree of its circularity.
Acknowledgement/Funding
None
