Influence of Obstructive Sleep Apnea on the Risk of Dental Caries: Insights from a 13-Year Population-Based Retrospective Study

KNOWLEDGE TRANSFER STATEMENT

Obstructive sleep apnea has been proven to have a great negative impact on patients, and the relationship between sleep apnea and dental caries is still inconclusive. Our study shows that patients with sleep apnea and those older than 45 y have a significant risk of dental caries.

Temporal Structures in Positron Spectra and Charge-Sign Effects in Galactic Cosmic Rays

We present the precision measurements of 11 years of daily cosmic positron fluxes in the rigidity range from 1.00 to 41.9 GV based on 3.4×10^{6} positrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The positron fluxes show distinctly different time variations from the electron fluxes at short and long timescales. A hysteresis between the electron fluxes and the positron fluxes is observed with a significance greater than 5σ at rigidities below 8.5 GV. On the contrary, the positron fluxes and the proton fluxes show similar time variation. Remarkably, we found that positron fluxes are modulated more than proton fluxes with a significance greater than 5σ for rigidities below 7 GV. These continuous daily positron fluxes, together with AMS daily electron, proton, and helium fluxes over an 11-year solar cycle, provide unique input to the understanding of both the charge-sign and mass dependencies of cosmic rays in the heliosphere.

Everolimus-Eluting Stents or Bypass Surgery for Multivessel Disease in Diabetics: The BEST Extended Follow-Up Study

BACKGROUND

Diabetes mellitus is associated with more complex coronary artery diseases. Coronary artery bypass grafting (CABG) is a preferred revascularization strategy over percutaneous coronary intervention (PCI) in diabetics with multivessel coronary artery disease (MVD).

OBJECTIVES

This study sought to examine the different prognostic effects of revascularization strategies according to the diabetes status from the randomized BEST (Randomized Comparison of Coronary Artery Bypass Surgery and Everolimus-Eluting Stent Implantation in the Treatment of Patients With Multivessel Coronary Artery Disease) trial.

METHODS

Patients (n = 880) with MVD were randomly assigned to undergo PCI with an everolimus-eluting stent vs CABG stratified by diabetics (n = 363) and nondiabetics (n = 517). The primary endpoint was the composite of death, myocardial infarction, or target vessel revascularization during a median follow-up of 11.8 years (IQR: 10.6-12.5 years).

RESULTS

In diabetics, the primary endpoint rate was significantly higher in the PCI group than in the CABG group (43% and 32%; HR: 1.53; 95% CI: 1.12-2.08; P = 0.008). However, in nondiabetics, no significant difference was found between the groups (PCI group, 29%; CABG group, 29%; HR: 0.97; 95% CI: 0.67-1.39; P = 0.86; Pinteraction= 0.009). Irrespective of the presence of diabetes, no significant between-group differences were found in the rate of a safety composite of death, myocardial infarction, or stroke and mortality rate. However, the rate of any repeat revascularization was significantly higher in the PCI group than in the CABG group.

CONCLUSIONS

In diabetics with MVD, CABG was associated with better clinical outcomes than PCI. However, the mortality rate was similar between PCI and CABG irrespective of diabetes status during an extended follow-up. (Ten-Year Outcomes of Randomized Comparison of Coronary Artery Bypass Surgery and Everolimus-Eluting Stent Implantation in the Treatment of Patients With Multivessel Coronary Artery Disease [BEST Extended], NCT05125367; Randomized Comparison of Coronary Artery Bypass Surgery and Everolimus-Eluting Stent Implantation in the Treatment of Patients With Multivessel Coronary Artery Disease [BEST], NCT00997828).

Impact of Optimal Medical Therapy on Long-Term Outcomes After Myocardial Revascularization for Multivessel Coronary Disease

Although optimal medical therapy (OMT) after coronary revascularization is advocated for intensive secondary prevention, its criteria and effect on long-term outcomes are uncertain. Using data from the ASAN-Multivessel (Asan Medical Center-Multivessel Revascularization) registry, we identified 8,311 patients who underwent coronary artery bypass grafting (CABG) (n = 3,115) or percutaneous coronary intervention (PCI) (n = 5,196). OMT was defined as the combination of minimum of 3 medications in 4 drug classes (antiplatelet drugs, statins, β blockers, and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers). Two primary outcomes were all-cause mortality and serious composite outcome of death, spontaneous myocardial infarction, or stroke at 10 years. Of 8,311 patients, 4,321 (52.0%) followed OMT. In the 3,397 propensity-score-matched cohort, OMT status compared with non-OMT status was significantly associated with a lower risk of all-cause mortality (10.7% vs 18.7%; hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.47 to 0.65) and serious composite outcome (14.5% vs 22.5%, HR 0.635, 95% CI 0.55 to 0.73) at 10 years. The association on 10-year mortality was more prominent in the PCI group (HR 0.45, 95% CI 0.36 to 0.56) than in the CABG group (HR 0.72, 95% CI 0.58 to 0.90) with a significant interaction (p = 0.001). Overall findings were consistent using different OMT criteria (all 4 types of medications). In conclusion, OMT significantly lowered the risks of mortality and major cardiovascular events at 10 years in patients with multivessel revascularization. The OMT impact on mortality was more remarkable in the PCI group than in the CABG group. This work was registered at http://ClinicalTrials.gov (Identifier: NCT02039752).

Properties of Cosmic-Ray Sulfur and Determination of the Composition of Primary Cosmic-Ray Carbon, Neon, Magnesium, and Sulfur: Ten-Year Results from the Alpha Magnetic Spectrometer

We report the properties of primary cosmic-ray sulfur (S) in the rigidity range 2.15 GV to 3.0 TV based on 0.38×10^{6} sulfur nuclei collected by the Alpha Magnetic Spectrometer experiment (AMS). We observed that above 90 GV the rigidity dependence of the S flux is identical to the rigidity dependence of Ne-Mg-Si fluxes, which is different from the rigidity dependence of the He-C-O-Fe fluxes. We found that, similar to N, Na, and Al cosmic rays, over the entire rigidity range, the traditional primary cosmic rays S, Ne, Mg, and C all have sizeable secondary components, and the S, Ne, and Mg fluxes are well described by the weighted sum of the primary silicon flux and the secondary fluorine flux, and the C flux is well described by the weighted sum of the primary oxygen flux and the secondary boron flux. The primary and secondary contributions of the traditional primary cosmic-ray fluxes of C, Ne, Mg, and S (even Z elements) are distinctly different from the primary and secondary contributions of the N, Na, and Al (odd Z elements) fluxes. The abundance ratio at the source for S/Si is 0.167±0.006, for Ne/Si is 0.833±0.025, for Mg/Si is 0.994±0.029, and for C/O is 0.836±0.025. These values are determined independent of cosmic-ray propagation.

Temporal Structures in Electron Spectra and Charge Sign Effects in Galactic Cosmic Rays

We present the precision measurements of 11 years of daily cosmic electron fluxes in the rigidity interval from 1.00 to 41.9 GV based on 2.0×10^{8} electrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The electron fluxes exhibit variations on multiple timescales. Recurrent electron flux variations with periods of 27 days, 13.5 days, and 9 days are observed. We find that the electron fluxes show distinctly different time variations from the proton fluxes. Remarkably, a hysteresis between the electron flux and the proton flux is observed with a significance of greater than 6σ at rigidities below 8.5 GV. Furthermore, significant structures in the electron-proton hysteresis are observed corresponding to sharp structures in both fluxes. This continuous daily electron data provide unique input to the understanding of the charge sign dependence of cosmic rays over an 11-year solar cycle.

Myocardial Scar and Revascularization on Mortality in Ischemic Cardiomyopathy (from the Late Gadolinium Enhancement Cardiac Magnetic Resonance Study)

Myocardial viability test to guide revascularization remains uncertain in patients with ischemic cardiomyopathy. We evaluated the different impacts of revascularization on cardiac mortality according to the extent of myocardial scar assessed by cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) in patients with ischemic cardiomyopathy. A total of 404 consecutive patients with significant coronary artery disease and an ejection fraction ≤35% were assessed by LGE-CMR before revascularization. Of them, 306 patients underwent revascularization and 98 patients received medical treatment alone. The primary outcome was cardiac death. During a median follow-up of 6.3 years, cardiac death occurred in 158 patients (39.1%). Revascularization was associated with a significantly lower risk of cardiac death than medical treatment alone in the overall population (adjusted hazard ratio [aHR] 0.29, 95% confidence interval (CI) 0.19 to 0.45, p <0.001). There was a significant interaction between the number of segments with >75% transmural LGE and revascularization on the risk of cardiac death (p = 0.037 for interaction). In patients with limited myocardial scar (<6 segments with >75% transmural LGE, n = 354), revascularization had a significantly lower risk of cardiac death than medical treatment alone (aHR 0.24, 95% CI 0.15 to 0.37, p <0.001); in patients with extensive myocardial scar (≥6 segments with >75% transmural LGE, n = 50), there was no significant difference between revascularization and medical treatment alone regarding the risk of cardiac death (aHR 1.33, 95% CI 0.46 to 3.80, p = 0.60). In conclusion, the assessment of myocardial scar by LGE-CMR may be helpful in the decision-making process for revascularization in patients with ischemic cardiomyopathy.

Everolimus-Eluting Stents or Bypass Surgery for Multivessel Coronary Artery Disease: Extended Follow-Up Outcomes of Multicenter Randomized Controlled BEST Trial

BACKGROUND

Long-term comparative outcomes after percutaneous coronary intervention (PCI) with everolimus-eluting stents and coronary artery bypass grafting (CABG) are limited in patients with multivessel coronary artery disease.

METHODS

This prospective, multicenter, randomized controlled trial was conducted in 27 international heart centers and was designed to randomly assign 1776 patients with angiographic multivessel coronary artery disease to receive PCI with everolimus-eluting stents or CABG. After inclusion of 880 patients (438 in the PCI group and 442 in the CABG group) between July 2008 and September 2013, the study was terminated early because of slow enrollment. The primary end point was the composite of death from any cause, myocardial infarction, or target vessel revascularization.

RESULTS

During a median follow-up of 11.8 years (interquartile range, 10.6-12.5 years; maximum, 13.7 years), the primary end point occurred in 151 patients (34.5%) in the PCI group and 134 patients (30.3%) in the CABG group (hazard ratio [HR], 1.18 [95% CI, 0.88-1.56]; P=0.26). No significant differences were seen in the occurrence of a safety composite of death, myocardial infarction, or stroke between groups (28.8% and 27.1%; HR, 1.07 [95% CI, 0.75-1.53]; P=0.70), as well as the occurrence of death from any cause (20.5% and 19.9%; HR, 1.04 [95% CI, 0.65-1.67]; P=0.86). However, spontaneous myocardial infarction (7.1% and 3.8%; HR, 1.86 [95% CI, 1.06-3.27]; P=0.031) and any repeat revascularization (22.6% and 12.7%; HR, 1.92 [95% CI, 1.58-2.32]; P<0.001) were more frequent after PCI than after CABG.

CONCLUSIONS

In patients with multivessel coronary artery disease, there were no significant differences between PCI and CABG in the incidence of major adverse cardiac events, the safety composite end point, and all-cause mortality during the extended follow-up.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifiers: NCT05125367 and NCT00997828.

Properties of Daily Helium Fluxes

We present the precision measurement of 2824 daily helium fluxes in cosmic rays from May 20, 2011 to October 29, 2019 in the rigidity interval from 1.71 to 100 GV based on 7.6×10^{8} helium nuclei collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The helium flux and the helium to proton flux ratio exhibit variations on multiple timescales. In nearly all the time intervals from 2014 to 2018, we observed recurrent helium flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. In the entire time period, we found that below ∼7  GV the helium flux exhibits larger time variations than the proton flux, and above ∼7  GV the helium to proton flux ratio is time independent. Remarkably, below 2.4 GV a hysteresis between the helium to proton flux ratio and the helium flux was observed at greater than the 7σ level. This shows that at low rigidity the modulation of the helium to proton flux ratio is different before and after the solar maximum in 2014.

Periodicities in the Daily Proton Fluxes from 2011 to 2019 Measured by the Alpha Magnetic Spectrometer on the International Space Station from 1 to 100 GV

We present the precision measurement of the daily proton fluxes in cosmic rays from May 20, 2011 to October 29, 2019 (a total of 2824 days or 114 Bartels rotations) in the rigidity interval from 1 to 100 GV based on 5.5×10^{9} protons collected with the Alpha Magnetic Spectrometer aboard the International Space Station. The proton fluxes exhibit variations on multiple timescales. From 2014 to 2018, we observed recurrent flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. The rigidity dependence of the 27-day periodicity is different from the rigidity dependences of 9-day and 13.5-day periods. Unexpectedly, the strength of 9-day and 13.5-day periodicities increases with increasing rigidities up to ∼10  GV and ∼20  GV, respectively. Then the strength of the periodicities decreases with increasing rigidity up to 100 GV.

Long-Term Outcomes After Percutaneous Coronary Intervention With Second-Generation Drug-Eluting Stents or Coronary Artery Bypass Grafting for Multivessel Coronary Disease

More evidence is required with respect to the comparative effectiveness of percutaneous coronary intervention (PCI) with second-generation drug-eluting stents (DESs) versus coronary artery bypass grafting (CABG) in contemporary clinical practice. This prospective observational registry-based study compared the outcomes of 6,647 patients with multivessel disease who underwent PCI with second-generation DES (n = 3,858) or CABG (n = 2,789) between January 2006 and June 2018 and for whom follow-up data were available for at least 2 to 13 years (median 4.8). The primary outcome was a composite of death, spontaneous myocardial infarction, or stroke. Baseline differences were adjusted using propensity scores and inverse probability weighting. In the overall cohort, there were no significant between-group differences in the adjusted risks for the primary composite outcome (hazard ratio [HR] for PCI vs CABG 1.03, 95% confidence interval [CI] 0.86 to 1.25, p = 0.73) and all-cause mortality (HR 0.95, 95% CI 0.76 to 1.20, p = 0.68). This relative treatment effect on the primary outcome was similar in patients with diabetes (HR 1.15, 95% CI 0.91 to 1.46, p = 0.25) and without diabetes (HR 0.95, 95% CI 0.73 to 1.22, p = 0.67) (p for interaction = 0.24). The adjusted risk of the primary outcome was significantly greater after PCI than after CABG in patients with left main involvement (HR 1.39, 95% CI 1.01 to 1.90, p = 0.044), but not in those without left main involvement (HR 0.94, 95% CI 0.76 to 1.16, p = 0.56) (p = 0.03 for interaction). In this prospective real-world long-term registry, we observed that the risk for the primary composite of death, spontaneous myocardial infarction, or stroke was similar between PCI with contemporary DES and CABG.

Erratum: Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen [Phys. Rev. Lett. 127, 021101 (2021)]

This corrects the article DOI: 10.1103/PhysRevLett.127.021101.

Benefit of Sarcopenia Screening in Older Patients Undergoing Surgical Aortic Valve Replacement

BACKGROUND

Sarcopenia, known as physical frailty, is highly prevalent in older patients and is related to adverse outcomes post-cardiac surgery. However, whether sarcopenia assessment can reclassify an individual patients' risk, which is estimated by Society of Thoracic Surgeons-predicted risk of mortality scores in patients who undergo surgical aortic valve replacement, is unclear.

METHODS

This retrospective, single center, cohort study comprised 874 patients aged ≥65 years who underwent surgical aortic valve replacement between 2009 and 2016. Total skeletal muscle area was calculated using height-squared and was measured by preoperative computed tomography at the third lumbar vertebra inferior border using machine learning-based analysis. Sex-specific Z-scores were calculated and patients in the lowest Z-score tertile were considered to have sarcopenia. The primary endpoint was 30-day mortality, and secondary endpoints were in-hospital events, 1-year mortality, and long-term mortality.

RESULTS

Thirty-day mortality, 30-day in-hospital events, and one-year mortality rates were 4.7%, 17.6%, and 8.0%, respectively. As the Z-score decreased, early adverse event odds showed a stepwise increase. Sarcopenia were independently associated with higher 30-day mortality, 30-day in-hospital events, and 1-year mortality. Reclassification analyses showed improvements in the ability to predict early adverse events after adding the Z-scores over and above the Society of Thoracic Surgeons-predicted risk of mortality scores (All, p <0.005).

CONCLUSIONS

Sarcopenic patients had significantly higher risks of early adverse events and long-term mortality after undergoing surgical aortic valve replacement than non-sarcopenic patients. Sarcopenia determined by preoperative computed tomography can enhance the prediction of postoperative outcome risk.

Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen

We report the properties of sodium (Na) and aluminum (Al) cosmic rays in the rigidity range 2.15 GV to 3.0 TV based on 0.46 million sodium and 0.51 million aluminum nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. We found that Na and Al, together with nitrogen (N), belong to a distinct cosmic ray group. In this group, we observe that, similar to the N flux, both the Na flux and Al flux are well described by the sums of a primary cosmic ray component (proportional to the silicon flux) and a secondary cosmic ray component (proportional to the fluorine flux). The fraction of the primary component increases with rigidity for the N, Na, and Al fluxes and becomes dominant at the highest rigidities. The Na/Si and Al/Si abundance ratios at the source, 0.036±0.003 for Na/Si and 0.103±0.004 for Al/Si, are determined independent of cosmic ray propagation.

Properties of Heavy Secondary Fluorine Cosmic Rays: Results from the Alpha Magnetic Spectrometer

Precise knowledge of the charge and rigidity dependence of the secondary cosmic ray fluxes and the secondary-to-primary flux ratios is essential in the understanding of cosmic ray propagation. We report the properties of heavy secondary cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The fluorine spectrum deviates from a single power law above 200 GV. The heavier secondary-to-primary F/Si flux ratio rigidity dependence is distinctly different from the lighter B/O (or B/C) rigidity dependence. In particular, above 10 GV, the F/Si/B/O ratio can be described by a power law R^{δ} with δ=0.052±0.007. This shows that the propagation properties of heavy cosmic rays, from F to Si, are different from those of light cosmic rays, from He to O, and that the secondary cosmic rays have two classes.

Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×10^{6} iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. This shows that unexpectedly Fe and He, C, and O belong to the same class of primary cosmic rays which is different from the primary cosmic rays Ne, Mg, and Si class.

Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary cosmic rays, neon (Ne), magnesium (Mg), and silicon (Si), measured in the rigidity range 2.15 GV to 3.0 TV with 1.8×10^{6}  Ne, 2.2×10^{6}  Mg, and 1.6×10^{6}  Si nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The Ne and Mg spectra have identical rigidity dependence above 3.65 GV. The three spectra have identical rigidity dependence above 86.5 GV, deviate from a single power law above 200 GV, and harden in an identical way. Unexpectedly, above 86.5 GV the rigidity dependence of primary cosmic rays Ne, Mg, and Si spectra is different from the rigidity dependence of primary cosmic rays He, C, and O. This shows that the Ne, Mg, and Si and He, C, and O are two different classes of primary cosmic rays.

Early Surgery or Conservative Care for Asymptomatic Aortic Stenosis

BACKGROUND

The timing and indications for surgical intervention in asymptomatic patients with severe aortic stenosis remain controversial.

METHODS

In a multicenter trial, we randomly assigned 145 asymptomatic patients with very severe aortic stenosis (defined as an aortic-valve area of ≤0.75 cm² with either an aortic jet velocity of ≥4.5 m per second or a mean transaortic gradient of ≥50 mm Hg) to early surgery or to conservative care according to the recommendations of current guidelines. The primary end point was a composite of death during or within 30 days after surgery (often called operative mortality) or death from cardiovascular causes during the entire follow-up period. The major secondary end point was death from any cause during follow-up.

RESULTS

In the early-surgery group, 69 of 73 patients (95%) underwent surgery within 2 months after randomization, and there was no operative mortality. In an intention-to-treat analysis, a primary end-point event occurred in 1 patient in the early-surgery group (1%) and in 11 of 72 patients in the conservative-care group (15%) (hazard ratio, 0.09; 95% confidence interval [CI], 0.01 to 0.67; P = 0.003). Death from any cause occurred in 5 patients in the early-surgery group (7%) and in 15 patients in the conservative-care group (21%) (hazard ratio, 0.33; 95% CI, 0.12 to 0.90). In the conservative-care group, the cumulative incidence of sudden death was 4% at 4 years and 14% at 8 years.

CONCLUSIONS

Among asymptomatic patients with very severe aortic stenosis, the incidence of the composite of operative mortality or death from cardiovascular causes during the follow-up period was significantly lower among those who underwent early aortic-valve replacement surgery than among those who received conservative care. (Funded by the Korean Institute of Medicine; RECOVERY ClinicalTrials.gov number, NCT01161732.).

Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of ^{3}He and ^{4}He fluxes are presented. The measurements are based on 100 million ^{4}He nuclei in the rigidity range from 2.1 to 21 GV and 18 million ^{3}He from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the ^{3}He and ^{4}He fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the ^{3}He/^{4}He flux ratio is measured for the first time. Below 4 GV, the ^{3}He/^{4}He flux ratio was found to have a significant long-term time dependence. Above 4 GV, the ^{3}He/^{4}He flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law ∝R^{Δ} with Δ=-0.294±0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.

Towards Understanding the Origin of Cosmic-Ray Electrons

Precision results on cosmic-ray electrons are presented in the energy range from 0.5 GeV to 1.4 TeV based on 28.1×10^{6} electrons collected by the Alpha Magnetic Spectrometer on the International Space Station. In the entire energy range the electron and positron spectra have distinctly different magnitudes and energy dependences. The electron flux exhibits a significant excess starting from 42.1_{-5.2}^{+5.4}  GeV compared to the lower energy trends, but the nature of this excess is different from the positron flux excess above 25.2±1.8  GeV. Contrary to the positron flux, which has an exponential energy cutoff of 810_{-180}^{+310}  GeV, at the 5σ level the electron flux does not have an energy cutoff below 1.9 TeV. In the entire energy range the electron flux is well described by the sum of two power law components. The different behavior of the cosmic-ray electrons and positrons measured by the Alpha Magnetic Spectrometer is clear evidence that most high energy electrons originate from different sources than high energy positrons.

Towards Understanding the Origin of Cosmic-Ray Positrons

Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million positrons collected by the Alpha Magnetic Spectrometer on the International Space Station. The positron flux exhibits complex energy dependence. Its distinctive properties are (a) a significant excess starting from 25.2±1.8  GeV compared to the lower-energy, power-law trend, (b) a sharp dropoff above 284_{-64}^{+91}  GeV, (c) in the entire energy range the positron flux is well described by the sum of a term associated with the positrons produced in the collision of cosmic rays, which dominates at low energies, and a new source term of positrons, which dominates at high energies, and (d) a finite energy cutoff of the source term of E_{s}=810_{-180}^{+310}  GeV is established with a significance of more than 4σ. These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter annihilation or from other astrophysical sources.

The Impact of Cerebral Atherosclerosis According to Location on Prognosis after Coronary Artery Bypass Grafting

BACKGROUND

In the previous prospective observational study, we found that cerebral atherosclerosis is an independent predictor of acute stroke after coronary artery bypass grafting (CABG). However, it is unknown whether intracranial cerebral atherosclerosis (ICAS) is important as much as extracranial cerebral atherosclerosis (ECAS) in estimating the risk of post-CABG adverse events. Extending the previous study, we aimed to investigate the immediate and long-term prognostic value of the location of cerebral atherosclerosis in CABG patients.

METHODS

This follow-up study of previously reported prospective cohort included 1,367 consecutive patients who received CABG between 2004 and 2007. All patients underwent preoperative magnetic resonance angiography (MRA) to assess intracranial and ECAS, both defined by significant steno-occlusion (≥50%). Participants were classified into 4 groups according to the location of cerebral atherosclerosis: no cerebral atherosclerosis, ECAS only, ICAS only, and ECAS + ICAS. Post-CABG stroke within 14 days (immediate outcome) and mortality (long-term outcome) following CABG were compared between the groups. Survival data for all participants through June 2016 were obtained from the Korean National Registry of Vital Statistics. The Cox proportional hazards model was used to estimate the hazard ratio (HR) of post-CABG stroke and mortality; patients lacking cerebral atherosclerosis were defined as the reference group.

RESULTS

The median follow-up duration after CABG was 9.2 years (interquartile range 8.4-10.2 years). Of the participants, 278 (20.3%) patients had ICAS only, while 269 (19.7%) and 347 (25.4%) showed ECAS only and ECAS + ICAS, respectively, in their preoperative MRA. Having ICAS only (HR 5.07; 95% CI 1.37-18.75; p = 0.015) and having ECAS + ICAS (HR 8.43; 95% CI, 2.48-28.61; p = 0.001) independently predicted the immediate stroke, whereas being with ECAS only did not (HR 1.71; 95% CI 0.35-8.50; p = 0.509). Conversely, ICAS-only status was not independently associated with long-term mortality (HR 1.22; 95% CI 0.90-1.65; p = 0.207), whereas ECAS-only status (HR 1.42; 95% CI 1.05-1.90; p = 0.021) and ECAS + ICAS status (HR 1.58; 95% CI 1.20-2.07; p = 0.001) showed independent associations.

CONCLUSIONS

Over 10 years of follow-up, cerebral atherosclerosis significantly associated with the development of adverse outcomes after CABG. The prognostic value of ICAS might be different from that of ECAS; immediate post-CABG stroke was more closely associated with ICAS, whereas there was a closer association between long-term post-CABG mortality and ECAS.

Observation of Complex Time Structures in the Cosmic-Ray Electron and Positron Fluxes with the Alpha Magnetic Spectrometer on the International Space Station

We present high-statistics, precision measurements of the detailed time and energy dependence of the primary cosmic-ray electron flux and positron flux over 79 Bartels rotations from May 2011 to May 2017 in the energy range from 1 to 50 GeV. For the first time, the charge-sign dependent modulation during solar maximum has been investigated in detail by leptons alone. Based on 23.5×10^{6} events, we report the observation of short-term structures on the timescale of months coincident in both the electron flux and the positron flux. These structures are not visible in the e^{+}/e^{-} flux ratio. The precision measurements across the solar polarity reversal show that the ratio exhibits a smooth transition over 830±30 days from one value to another. The midpoint of the transition shows an energy dependent delay relative to the reversal and changes by 260±30 days from 1 to 6 GeV.

Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station

A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2 GV to 3.3 TV based on 2.2×10^{6} events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. The spectral index rapidly hardens at high rigidities and becomes identical to the spectral indices of primary He, C, and O cosmic rays above ∼700  GV. We observed that the nitrogen flux Φ_{N} can be presented as the sum of its primary component Φ_{N}^{P} and secondary component Φ_{N}^{S}, Φ_{N}=Φ_{N}^{P}+Φ_{N}^{S}, and we found Φ_{N} is well described by the weighted sum of the oxygen flux Φ_{O} (primary cosmic rays) and the boron flux Φ_{B} (secondary cosmic rays), with Φ_{N}^{P}=(0.090±0.002)×Φ_{O} and Φ_{N}^{S}=(0.62±0.02)×Φ_{B} over the entire rigidity range. This corresponds to a change of the contribution of the secondary cosmic ray component in the nitrogen flux from 70% at a few GV to <30% above 1 TV.

Observation of Fine Time Structures in the Cosmic Proton and Helium Fluxes with the Alpha Magnetic Spectrometer on the International Space Station

We present the precision measurement from May 2011 to May 2017 (79 Bartels rotations) of the proton fluxes at rigidities from 1 to 60 GV and the helium fluxes from 1.9 to 60 GV based on a total of 1×10^{9} events collected with the Alpha Magnetic Spectrometer aboard the International Space Station. This measurement is in solar cycle 24, which has the solar maximum in April 2014. We observed that, below 40 GV, the proton flux and the helium flux show nearly identical fine structures in both time and relative amplitude. The amplitudes of the flux structures decrease with increasing rigidity and vanish above 40 GV. The amplitudes of the structures are reduced during the time period, which started one year after solar maximum, when the proton and helium fluxes steadily increase. Above ∼3  GV the p/He flux ratio is time independent. We observed that below ∼3  GV the ratio has a long-term decrease coinciding with the period during which the fluxes start to rise.

Observation of New Properties of Secondary Cosmic Rays Lithium, Beryllium, and Boron by the Alpha Magnetic Spectrometer on the International Space Station

We report on the observation of new properties of secondary cosmic rays Li, Be, and B measured in the rigidity (momentum per unit charge) range 1.9 GV to 3.3 TV with a total of 5.4×10^{6} nuclei collected by AMS during the first five years of operation aboard the International Space Station. The Li and B fluxes have an identical rigidity dependence above 7 GV and all three fluxes have an identical rigidity dependence above 30 GV with the Li/Be flux ratio of 2.0±0.1. The three fluxes deviate from a single power law above 200 GV in an identical way. This behavior of secondary cosmic rays has also been observed in the AMS measurement of primary cosmic rays He, C, and O but the rigidity dependences of primary cosmic rays and of secondary cosmic rays are distinctly different. In particular, above 200 GV, the secondary cosmic rays harden more than the primary cosmic rays.

Observation of the Identical Rigidity Dependence of He, C, and O Cosmic Rays at High Rigidities by the Alpha Magnetic Spectrometer on the International Space Station

We report the observation of new properties of primary cosmic rays He, C, and O measured in the rigidity (momentum/charge) range 2 GV to 3 TV with 90×10^{6} helium, 8.4×10^{6} carbon, and 7.0×10^{6} oxygen nuclei collected by the Alpha Magnetic Spectrometer (AMS) during the first five years of operation. Above 60 GV, these three spectra have identical rigidity dependence. They all deviate from a single power law above 200 GV and harden in an identical way.

A Case of Persistent and Recurrent Ventricular Fibrillation with Successful Resuscitation and Good Neurological Outcome

A 49-year-old man suffering from chest pain collapsed on arrival at an emergency department. Ventricular fibrillation was confirmed and he survived neurologically normal after 22 defibrillation shocks. This case attests that persistent and recurrent ventricular fibrillation is still compatible with good neurological outcome. Energetic and persistent efforts should be continued in such cases. Amiodarone should be considered early in the course of refractory ventricular fibrillation.

An Analysis of Unscheduled Return Visits to the Accident and Emergency Department of a General Public Hospital

Objectives

To identify the reasons for unscheduled return visits to a public emergency department and possible strategies to reduce unscheduled return visits.

Design

Cross-sectional survey.

Setting

A public emergency department in Hong Kong.

Patients

Unscheduled return visits within 48 hours in a three-month period from 14 January 2000 to 15 April 2000.

Main outcome measures

Patients' epidemiological characteristics, reasons, complaints and outcome of the unscheduled return visits.

Results

During the study period, 3.3% (1,060) of the attendance was unscheduled return visits within 48 hours as recorded in the computerized A&E Information System of the hospital. However, only 738 patients (70%) responded to the questionnaire. These 738 patients formed the study population for further analysis. Illness-related factors accounted for 87% of the total unscheduled return visits. Patient-related factors were responsible for about 10% of unscheduled return visits. Doctor-related factors accounted for about 3% of unscheduled return visits. There was only one system-related unscheduled return visit. For the outcome of return visits, about 76% (559) was discharged after the second consultation. About 5% (40) was referred to specialist clinics. Around 24% (179) of patients was admitted. Of those admitted, 78% (140) was illness-related, 13% (23) was patient-related and 9% (16) was doctor-related. Upper respiratory tract infection was the most frequent complaint (34%), followed by painful conditions (23%) and injuries (10%). For children at or below 10 years of age, upper respiratory tract infection (60%) and febrile illness (15%) were the most frequent complaints.

Conclusions

The study found that the reasons for return visits were multiple. These “unscheduled return visits” should not be automatically regarded as poor indicator of service. Better patient education, organized family practice system, upgrading of professional training and targeted audit are possible means to reduce unscheduled return visits.

Go-Kart Related Injuries: A Local Scene

Objectives

To study the characteristics and nature of injuries relating to go-kart in the local setting and to compare the findings with those reported in the medical literature.

Methods

A prospective survey of patients with go-kart related injuries attending the accident and emergency department of a public district hospital in Hong Kong within the year 2002. The data were analysed and compared with previous studies.

Results

Forty-two patients were collected in the study. The mean age was 26 years. Ten patients (23.8%) were at or below the age of 20 years. Twenty-nine patients (69.0%) were males. Out of the 42 patients, all were riders except one who was a bystander. Thirty-three patients (78.6%) had injuries in indoor tracks. Ten (23.8%) patients were admitted and five (50%) of those admitted required operations. There was no fatality. Twenty-seven patients (64.3%) had only single injury. Most (64.2%) were minor soft tissue injuries. However, fractures or dislocations occurred in 13 patients (31.0%). Two patients (4.8%) suffered from internal organ injuries. Isolated head and facial injuries occurred in 11.9% of patients. All were simple concussion. Nine patients (21.4%) suffered from isolated lower limb injuries, with more than half sustaining fractures or dislocations. Collision with other karts (40.5%) was the most frequent mechanism of injury. Riding in outdoor track was associated significantly with increased admission when compared with indoor track (77.8% vs 9.1%, p<0.001). There was no association between rider's age, gender, previous riding or injury experience, or the presence of briefing before the race with the rate of admission.

Conclusion

Go-kart racing and working on racing track can be a recreation or occupation with potential dangers. In our study, characteristics of patients, mechanisms and types of injuries were similar to other western studies. Accidents on outdoor tracks appeared to be more serious and more likely admitted than those on indoor circuits. Special safety precautions on outdoor events may help to reduce the severity of injuries. However, drivers with more riding or injury experiences were not exempted from severe injuries. Moreover, presence of briefing before the race did not help reduce the admission rate either. Perhaps, a safe and careful attitude of the rider and a seriously conducted briefing by a qualified instructor would be more important to reduce accidents. Further proper large scale controlled epidemiological studies will definitely help to improve the understanding of go-kart related injuries.

Pancreatic Injury: An Uncommon Cause of Abdominal Pain after Blunt Trauma

Blunt pancreatic injury is an uncommon cause of traumatic abdominal pain. Early diagnosis is difficult due to its subtle initial presentation, both clinically and on imaging study. Dilemma between a watchful expectant management and thorough initial investigation may arise. The management of a 44-year-old man presenting to the emergency department because of generalised trunk pain after blunt trauma is reported.

Golf-related Injuries: Case Series and Reports

Within the year 2002, eleven patients attended the emergency department of a public district hospital because of golf-related injuries. This attested to the low but occasionally serious risk of this type of sport activity. As golf is becoming increasingly popular in Hong Kong, it is expected that emergency physicians will see more and more golf-related injuries.

Acute Ischaemic Stroke: Management, Recent Advances and Controversies

Acute ischaemic stroke is a major cause of death and disability. It may become an enormous burden to the patients themselves, their families as well as the health care systems. Patients at risk of airway, breathing and circulatory compromise should receive prompt resuscitation. Vital parameters and neurological status should be closely monitored. Attentions to blood pressure, temperature and sugar profile are important. The significance of early and correct diagnosis and subsequent treatment cannot be over-emphasised. There have been tremendous recent advances in different treatment modalities in acute stroke management. Various recanalisation modalities include intravenous and/or intra-arterial thrombolysis, acute defibrinogenation, anti-platelet treatment and anticoagulation. Carotid endarterectomy and endovascular strategies are recommended in selected patients. Advanced neuro-imaging techniques and neuroprotectants are being evaluated. Multidisciplinary stroke teams have been shown to improve patient survival and functional outcome. Pre-defined algorithms and protocols should be in place to expedite smooth and effective delivery of stroke service. Future directions should be aimed at exploring safer recanalisation modalities and extending the limit of the current 3-hour treatment window for thrombolysis.

A Retrospective Study of Seclusion in an Emergency Department

Objectives

To study the practice of seclusion in an emergency department (ED) and to explore high-risk elements during seclusion.

Methods

The study consisted of two parts: an in-depth analysis on all incidents associated with seclusion in a six-year period (1998–2004) and a two-year (2002–2004) retrospective analysis of secluded patient records to understand the rationale and patient outcome.

Results

Part 1: A total of 9 incident records were collected. Four patients were related to setting fire. Five patients had violence or threat of violence. The median length of stay (LOS) in seclusion at the time of incident was 129 minutes. Although 66.7% of the patients had additional restraint prior to the seclusion, incidents still occurred. Two staff sustained injuries and hospital facilities were damaged in some of the incidents. Six patients were later admitted to psychiatric hospital. Part 2: 141 patient data were collected in the study (M: 89 and F: 52). The average monthly number of patients secluded was about 6. The mean age was 45 years (SD 19) and the mean LOS was 616 minutes (SD 478). There were three incidences (2.1%) during the two-year period. A total of 82 patients (58.2%) were associated with violence or threat of violence and 38 (46.3%) of the group had psychiatric illness; and 50 patients (35.5%) were associated with alcohol or drug intoxication. Ultimately, 56 patients (39.7%) were admitted to psychiatric hospital and 64 patients (45.4%) were treated and discharged from the ED.

Conclusion

Seclusion is a high-risk practice. In our department, the most frequent indication was violence (58.2%), with nearly half of them having history of psychiatric illness. Psychiatric illness had the highest risk for incidents, especially those with violence or threat of violence. The LOS in seclusion was relatively long in the ED and might be one of the risk factors for incidents. Inadequate removal of potentially dangerous belongings from patients before seclusion may end up with catastrophic outcomes. Curiously, ED nurses are not allowed to search patients before seclusion. They are exposed to legal liability in exercising restraint and in searching for potentially dangerous items from patients. It is suggested that clear protocols and quality assurance programs should be instituted to ensure safe seclusion.

Prognostic Predictive Values of the Initial Electrocardiogram with St-Segment Elevation Acute Myocardial Infarction in Chinese Patients

Objective

To study the electrocardiogram (ECG) features that predict 30-day mortality of ST-segment elevation acute myocardial infarction (STEMI) in Chinese patients.

Method

This was a retrospective study. Patients presenting within twelve hours after the onset of chest pain with ECG features compatible with STEMI and the diagnosis confirmed after admission were included in the study. Data taken into account included age, sex and thrombolytic therapy in the emergency department. The hospital records of the patients were later retrieved from the computer. The initial ECG performed in the emergency department were reviewed.

Results

A total of 98 patients were included in the study. There was no statistically significant relationship between 30-day mortality and the type of myocardial infarction or the magnitude of the ST segment changes. Distortion of the terminal portion of the QRS complex and prior evidence of myocardial infarction (in another location different from the presenting one) showed statistically significant relationship with 30-day mortality, with odds ratio 10.364 (95% CI 1.715–62.620) and 12.731 (95% CI 2.317–69.962) respectively.

Conclusion

In newly diagnosed STEMI patients, if there is evidence of terminal distortion of the QRS complex or prior ECG changes of myocardial infarction, the 30-day mortality will be significantly higher.

A Lady with Alarming Neck Swelling after Minor Head Injury

A 52-year-old woman with hidden ankylosing spondylitis for years attended the emergency department after a minor head injury. Rapid and alarming neck swelling appeared shortly after the initial consultation. Although the physical examination and the lateral cervical spine X-ray did not suggest fracture, a later CT scan revealed a fracture line. A high index of suspicion and early use of the halo device are needed in order to prevent irreversible neurological damage in such patients.

Emergency Department Violence: a Local Scene

Objectives

To study the nature, frequency and magnitude of violence in a local emergency department.

Design

Prospective epidemiological study in a three-month period, during which involved staff filled in a survey form immediately after violence incidents.

Setting

Accident & Emergency Department of a public general hospital in the northeastern New Territories.

Population

Assailants and victims of violence in the emergency department.

Main outcome measures

Nature of violence, frequency, cause, morbidity, epidemiological characteristics of assailants and victims.

Results

There were 25 incidents with 26 assailants in the three-month period. The great majority was verbal abuse only (64%). No weapon was involved. Long waiting time (36%), deranged mental condition (28%) and dissatisfaction with service (20%) were the leading causes of violence. Assailants showed a predominance of male (69%) and age between 21–50 years. They were either patients (69%) or accompanying persons (31%). Nurses (59%) and to a lesser extent doctors (23%), were the main victims.

Conclusion

The incidence of emergency department violence (0.08%) was low and the majority was verbal abuse only. Nurses bore the brunt of the violence. Long waiting time, confused patients and dissatisfied patients were high risk factors.

Meeting the Media: Friend or Foe?

For various reasons, the emergency department is an area of interest for the media. As a result, emergency physicians have to prepare for the occasions of being interviewed by the media some day in their career. It is natural to have some anxiety and fear in meeting the media, especially for the inexperienced. However, developing a good relationship with the media would not only benefit the organisation and the specialty, but also the general public as well. This is a review of the preparation, techniques, tricks and pitfalls in dealing with the media, especially in regard to television interviews.

Ciguatera fish Poisoning: a Challenge to Emergency Physicians

Seven patients from two families presented with ciguatera poisoning after fish consumption. They suffered most of the typical clinical features of ciguatera poisoning and were given supportive treatments. Three of them were given mannitol infusion and showed improvement in symptoms. All of them were discharged within two days.

An Intravenous Drug Addict Presenting with ‘Shortness of Breath’: Case Report

A 49-year-old male intravenous drug addict attended the emergency department complaining of ‘shortness of breath’ for one day. He was discharged after evaluation and referred to the methadone clinic. He re-attended the next day complaining of neck stiffness and twitching of limbs for one day. The final diagnosis was tetanus. Although tetanus is rare in Hong Kong, high vigilance should still be maintained for its atypical presentations, especially in high-risk groups.