Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

Usefulness of echocardiographic parameters in predicting the incidence of ischemic stroke in Japanese patients with non-valvular atrial fibrillation

Background

Atrial fibrillation (AF) is a risk factor for ischemic stroke (IS). We developed a novel risk score of IS (HELT-E2S2 score) in non-valvular atrial fibrillation (NVAF) patients from the combined database of 5 major AF registries in Japan. However, this score does not include echocardiographic (Echo) parameters that have been reported to be risk factors of IS, such as left atrial diameter (LAD) enlargement or increased relative wall thickness (RWT) of left ventricle (LV).

Purpose

To investigate the predictive value of Echo parameters in Japanese patients with NVAF.

Methods

After excluding patients without the Echo data, 6,032 NVAF patients were analyzed in the present study. LAD was measured in the parasternal long axis view at the end-ventricular systole. RWT was calculated as (2x posterior wall thickness)/ LV end-diastolic dimension. We compared clinical characteristics and the incidence of IS between NVAF patients divided by LAD level (High/Low LAD group) and RWT level (High/Low RWT group). To balance the follow-up period among the registries, event data from individuals whose follow-up period exceeded 730 days were excluded from the analysis.

Results

The optimal cut-off value of LAD and RWT to predict the incidence of IS with the receiver operating characteristic analysis was 43.3 mm and 0.4167, respectively. Between the High/Low LAD groups (High LAD: n=2,640 vs. Low LAD: n=3,392), age (70.3±12.1 vs. 68.3±12.5 years; p<0.001), CHA2DS2-VASc score (3.02±1.84 vs. 2.57±1.78; p<0.001), HELT-E2S2 score (2.20±1.31 vs. 1.55±1.33; p<0.001), the prescription of oral anticoagulants (OACs) (69.5 vs. 51.5%; p<0.001), LV ejection fraction (60.4±13.4 vs. 64.4±10.7%; p<0.001) and RWT (0.401±0.091 vs. 0.396±0.082; p=0.02) were significantly different. Between the High/Low RWT groups (High RWT: n=2,293 vs. Low RWT: n=3,739), percentage of female (35.6 vs. 27.8%; p<0.001), age (71.2±12.1 vs. 68.0±12.4 years; p<0.001), CHA2DS2-VASc score (3.08±1.82 vs. 2.58±1.79; p<0.001), HELT-E2S2 score (2.10±1.39 vs. 1.67±1.31; p<0.001), the prescription of OACs (62.6 vs. 57.4%; p<0.001), LV ejection fraction (65.5±9.9 vs. 60.9±13.0%; p<0.001) and LAD (43.0±8.1 vs. 42.4±8.3; p=0.004) were significantly different. In Kaplan-Meier analysis, the incidence of IS was different between the groups during the median follow-up period of 730 days (High LAD vs. Low LAD; 1.82 vs. 1.00 per 100 person-years; p<0.001, by log-rank test, High RWT vs. Low RWT; 1.86 vs. 1.06; p<0.001) (Figure). Both High LAD (hazard ratio: 1.65, 95% CI: 1.12–2.46; p=0.01) and High RWT (hazard ratio: 1.43, 95% CI: 1.01–2.04; p=0.045) were independent predictors of the incidence of IS after adjustment by the components of the HELT-E2S2 score and other clinically relevant variables including co-existing diseases, gender, and the prescription of OACs (Table).

Conclusion

Echo parameters, LAD and RWT, were independently associated with the incidence of IS among Japanese patients with NVAF.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japan Agency for Medical Research and Development

Regional variations in patient selection and procedural characteristics for cryoballoon ablation of atrial fibrillation

Background

Cryoballoon ablation is a well-established anatomical approach for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Although widely adopted, regional variations in standards of care have not been well characterized.

Purpose

To evaluate regional variations in patient selection and procedural characteristics for PVI with cryoablation in the Cryo Global Registry (NCT02752737).

Methods

Patients with AF were enrolled from May 2016 to October 2021 at 128 sites in 37 countries. Patients were treated with cryoballoon ablation according to local clinical practice. Baseline subject and procedural characteristics were summarized for 8 regions (Central Asia and Russia, East Asia, Europe, Middle East, North America, South Africa, South America, and Southeast Asia). Procedure-related serious adverse events (SAEs) were evaluated in a subset of patients with ≥7 days of follow-up.

Results

A total of 3680 patients undergoing initial PVI for AF were included. Cryoballoon ablation was more commonly performed in patients with paroxysmal vs. persistent AF in all regions, and in males vs. females in all regions except Central Asia and Russia. Mean age ranged from 47±12 in the Middle East to 64±11 in East Asia. Regional variations were observed in the proportion of patients with common AF comorbidities undergoing cryoablation (Table 1). Median procedure time ranged from 61 (49–68) minutes in Central Asia and Russia to 95 (76–120) minutes in Southeast Asia. Median fluoroscopy time was ≤20 minutes in all regions. The use of 3D mapping was relatively uncommon except in North America (63.3%). Large variation was observed in the use of esophageal monitoring, whereas phrenic nerve monitoring was used in ≥97.7% of cases in all regions (Table 2). Same-day discharge was uncommon except in North and South America (37.8% and 26.5% of cases, respectively). Average freeze duration ranged from 153±41 seconds in Southeast Asia to 230±29 seconds in Central Asia and Russia. Mean number of applications per vein ranged from 1.2±0.4 in Central Asia and Russia to 2.1±1.0 in North America. Acute procedural success was ≥94.7% in all geographies and focal radiofrequency touch-up was required in ≤13.0% of cases. In 3126 subjects with ≥7 days of follow-up, 122 procedure-related SAEs were reported in 111 patients (3.6%), and 1 procedure-related death was reported during data collection.

Conclusion(s)

Despite regional variations in patient selection and procedural characteristics, PVI using cryoballoon ablation is performed with high acute success and short procedural times around the world.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.

Quality of life after first-line cryoablation of atrial fibrillation: results from the Cryo AF Global Registry

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): The registry was sponsored Medtronic, Inc., Minneapolis, MN.

Background

Atrial fibrillation (AF), the most common cardiac arrhythmia, burdening patients with a myriad of symptoms. Three recent randomized trials demonstrated that cryoballoon ablation (CBA) is superior to antiarrhythmic drugs (AADs) as a first-line treatment for the prevention of arrhythmia reoccurrence in patients with paroxysmal AF. However, the global outcome of CBA performed according to local standard of care as a first-line therapy for AF is not reported.

Purpose

To compare safety, efficacy, and quality of life outcomes in patients treated with CBA for first-line management of AF against patients treated with CBA following failed AAD therapy.

Methods

The Cryo AF Global Registry, an ongoing, prospective, multicenter registry, of AF patients undergoing index CBA performed according to local standards at 58 centers in 26 countries worldwide. In this analysis, subjects undergoing first-line cryoablation were compared to patients who were refractory to AAD therapy and/or taking AADs at baseline. Safety was assessed utilizing a composite of serious procedure-related complications. To evaluate efficacy, time-to-first atrial fibrillation, -flutter and/or -tachycardia (AF/AFL/AT) recurrence post a 90-day blanking period was compared between groups using Kaplan-Meier estimates. Quality of life was evaluated using the EQ-5D-3L questionnaire at baseline and at 12 months following CBA. Log-rank, two-sample t-test, and exact binomial tests were utilized to test difference between groups.

Results

Of 1,394 total patients, 433 (31.1%) were drug naïve prior to CBA. Patients in the AAD therapy cohort failed a mean of 1.2 ± 0.5 AADs before CBA. Freedom from AF/AFL/AT recurrence at 12 months was 87.8% in first-line patients compared to 81.6% in AAD-refractory patients (p<0.01). Serious adverse event rates were not statistically different (p=0.32) between first-line (2.3%) and AAD-refractory (3.4%) patients. First-line CBA resulted in a larger mean decline in symptoms upon follow-up, with 81% of patients reported to be symptom-free at 12 months. Further, first-line patients were prescribed AADs at a lower rate at discharge (18.6% vs.62.8%) and at 12-months (9.7% vs.29.9%) in comparison to patients in the AAD cohort. However, cryoablation did result in AAD prescriptions being reduced by approximately 50% in both cohorts from discharge to 12-months. As determined by the EQ-5D-3L score, quality of life improved for patients in both groups, with no significant difference between first-line and AAD-refractory patients (p=0.29).

Conclusion

This real-world global evaluation supports CBA as a safe and efficacious first-line treatment that improves the quality of life for patients with symptomatic AF.

Global utilization and outcomes of first-line cryoablation for atrial fibrillation

Background

Recent trials demonstrated the safety and efficacy of cryoballoon ablation prior to antiarrhythmic drug (AAD) usage in patients with paroxysmal atrial fibrillation (AF); however, global utilization and outcomes of first-line cryoablation in real-world AF patient management are unknown.

Purpose

To evaluate baseline characteristics and outcomes in patients selected for first-line cryoablation for treatment of AF.

Methods

The Cryo Global Registry (NCT02752737) is an ongoing, prospective, multicenter registry. In this analysis, AF patients with an index cryoballoon ablation performed according to local standards of care at 58 centers in 26 global countries were included. Subjects with no prior failed antiarrhythmic drug (AAD) usage and not taking an AAD at baseline were considered first-line and compared to drug-refractory patients who had failed an AAD prior to enrollment in the study and/or were taking an AAD at baseline. Baseline characteristics, serious procedure-related complication rates, and 12-month freedom from a ≥30sec AF/atrial flutter (AFL)/atrial tachycardia (AT) recurrence after a 90-day blanking period were compared between the groups.

Results

In total, 31% of the 1,394 patients (433 first-line, 961 drug-refractory) received a first-line cryoablation. The proportion of first-line enrollments by world region (3.7%-53.5%) and countries within region (i.e. EU: 0–59%) varied widely. Drug-refractory patients failed a mean of 1.2±0.5 AADs prior to cryoablation. First-line and drug-refractory patients were similar in age (60±13 vs 61±11), sex (35.1% vs 36.8% female), and CHA2DS2-VASC (2.0±1.6 vs 2.1±1.6). First-line was more often paroxysmal AF (87.3% vs 80.2%), with lower BMI (27±5 vs 28±5), diagnosed with AF fewer years (2.1±3.9 vs 3.7±5.0), and had smaller left atrial diameters (39±7 vs 42±8 mm; all p<0.05). Hypertension and history of congestive heart failure were less common in first-line (p<0.05), but similar rates of prior myocardial infarction, stroke, coronary artery disease, diabetes, and sleep apnea were reported. Procedure, left atrial dwell, and cryoapplication times were similar between cohorts (all p>0.05). Serious adverse event rates were not statistically different between first-line and drug-refractory patients (2.3% vs 3.4%, respectively; p=0.32). Freedom from AF/AFL/AT after cryoablation in first-line vs drug-refractory PAF was 90.0% (95% CI: 86.4–92.7%) and 84.4% (95% CI: 81.5–86.8%) and in first-line vs drug-refractory persistent AF was 72.9% (95% CI: 58.6–83.0%) vs 70.2% (95% CI: 62.9–76.4%), respectively. First-line ablation resulted in higher rates of freedom from arrhythmia recurrence (p=0.02).

Conclusion

First-line cryoablation in a real-world setting resulted in improved efficacy without increasing the risk of a safety event. These data support cryoablation as an early intervention strategy for treatment of AF.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.

Predictors for major bleeding in elderly (75 years and over) patients with non-valvular atrial fibrillation at high risk of bleeding: sub-analysis of the ANAFIE Registry

Background

In patients with atrial fibrillation (AF) receiving anticoagulant therapy, bleeding events are associated with reduced survival. Previous studies showed that bleeding events during anticoagulant therapy were more frequent in elderly AF patients than in younger patients. HAS-BLED score has been used to assess the risk of bleeding in AF patients. In patients at high bleeding risk (HAS-BLED score ≥3), we sought to identify other risk factors associated with major bleeding not included in HAS-BLED score in elderly non-valvular AF (NVAF) patients.

Purpose

The All Nippon Atrial Fibrillation In the Elderly (ANAFIE) Registry is a prospective, multicenter, observational study to collect real-world data on clinical status and prognosis in more than 30,000 Japanese patients (aged ≥75 y) with NVAF. This sub-analysis of the ANAFIE Registry assessed the 2-year outcomes and identified predictors for major bleeding in elderly NVAF patients with a high bleeding risk.

Methods

A total of 32,275 patients from the ANAFIE Registry were divided into 2 groups according to HAS-BLED score (≥3 [high-risk group] and ≤2 [reference group]). The annualized incidence rate, hazard ratio (HR) for clinical outcomes, and independent predictors for major bleeding were analyzed using Kaplan-Meier analysis and the Cox proportional-hazards model.

Results

A total of 6,826 patients constituted the high-risk group: mean age, 81.8 years old (75–80 years, 37.8%; 81–84 years, 33.9%; ≥85 years, 28.3%); male ratio, 72.2%; mean creatinine clearance (CrCL), 42.7 mL/min; history of major bleeding, 14.2%; presence of non-paroxysmal AF, 62.2%; mean total number of medicines used, 7.8. Anticoagulants were used in 91.2% (warfarin [WF], 29.9%; direct oral anticoagulants [DOACs], 61.2%). Proton-pump inhibitors (PPI) were administered in 46.5%. Compared to the reference group, the high-risk group had higher annualized incidence rates (/100 patient-year) of major bleeding (1.49 vs 0.97), intracranial hemorrhage (0.95 vs 0.70), gastrointestinal (GI) bleeding (2.63 vs 1.73), and all-cause mortality (5.50 vs 3.24). All-cause mortality more frequently occurred in patients aged ≥85 years compared to 75–79 years and those with CrCL <50 mL/min compared to CrCL ≥50 mL/min. In the high-risk group, DOAC subgroup had lower incidences of the above-mentioned outcomes other than GI bleeding than WF subgroup. The following relevant factors for major bleeding not included in HAS-BLED score were identified in the high-risk group: Body mass index (BMI) ≥25.0 kg/m2 (HR, 0.40), heart failure (HF) with reduced left ventricular ejection fraction (LVEF) (HR, 1.38), a fall within 1 year (HR, 2.29), and use of PPI (HR, 0.65).

Conclusions

Among elderly (≥75 years) Japanese NVAF patients in the high bleeding risk group (HAS-BLED score ≥3), HF with reduced LVEF, and a fall within 1 year were identified as independent predictors of major bleeding. BMI ≥25.0 kg/m2 and PPI use were protective for major bleeding.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Daiichi Sankyo Co., Ltd.

Influence of renal dysfunction on clinical outcomes in elderly patients with atrial fibrillation: a subanalysis of the phase 3, randomized, placebo-controlled ELDERCARE-AF trial

Background

Renal dysfunction is common in elderly patients with atrial fibrillation (AF) and is thought to be associated with increased risk of thromboembolic and bleeding events. Once-daily low-dose (15 mg) edoxaban was superior to placebo in preventing stroke or systemic embolic events (S/SEE) without significantly increasing major bleeding events in very elderly (≥80 years) non-valvular AF (NVAF) patients in whom standard oral anticoagulant therapy at approved doses was inappropriate (ELDERCARE-AF trial). Little is known about how renal dysfunction affects the effects of low-dose edoxaban in these patients.

Purpose

We used prespecified subgroup analysis to investigate the relation between renal function (assessed by creatinine clearance, CrCl) and the efficacy and safety of edoxaban in elderly NVAF patients.

Methods

ELDERCARE-AF patients were divided into 3 subgroups according to baseline CrCl: normal renal function/mild dysfunction (CrCl >50 mL/min), moderate renal dysfunction (CrCl ≥30 to ≤50 [“30–50”] mL/min) and severe renal dysfunction (CrCl ≥15 to <30 [“15–30”] mL/min). Primary efficacy and safety endpoints were annualized incidence of S/SEE and ISTH-defined major bleeding, respectively.

Results

Of 984 patients randomized to edoxaban 15 mg or placebo (each group N=492), 681 completed the trial. The 303 discontinuations were due to withdrawal of consent (n=158), death (n=135), or other causes (n=10). Discontinuation rate was the same in the edoxaban and placebo groups. S/SEE incidence in patients with CrCl >50, 30–50 and 15–30 mL/min was 2.0%, 1.3% and 3.5%, respectively, in edoxaban, and 4.4%, 4.6% and 9.7%, respectively, in placebo. In those with CrCl 30–50 and 15–30 mL/min, it was significantly lower in edoxaban than in placebo (adjusted hazard ratio [HR], 0.30 [95% CI, 0.10–0.91], p=0.03; and 0.33 [95% CI, 0.16–0.71], p<0.01, respectively). Incidence of major bleeding in patients with CrCl >50, 30–50 and 15–30 mL/min was 1.0%, 1.8% and 6.2%, respectively, in edoxaban, and 0.9%, 1.5% and 2.4%, respectively, in placebo. Incidence of major bleeding in those with CrCl 15–30 mL/min was higher in edoxaban but not significantly (adjusted HR, 2.53 [95% CI, 0.96–6.72], p=0.062). Incidence of gastrointestinal bleeding in patients with CrCl 15–30 mL/min was 4.3% in edoxaban and 1.6% in placebo (adjusted HR, 2.61 [95% CI, 0.79–8.68], p=0.12). Incidence of all-cause death in patients with CrCl >50, 30–50 and 15–30 mL/min was 5.8%, 6.8% and 15.2%, respectively, in edoxaban, and 7.0%, 6.3% and 15.5%, respectively, in placebo (no significant intergroup differences).

Conclusions

Incidence of S/SEE, major bleeding and all-cause death increased with declining renal function in elderly NVAF patients. Edoxaban 15 mg remained superior to placebo in preventing S/SEE, even in those with moderate to severe renal dysfunction. Incidence of major bleeding in patients with severe renal dysfunction was higher (non-significantly) with edoxaban than with placebo.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Daiichi-Sankyo Co., Ltd.

Healthcare utilization after cryoballoon ablation for treatment of atrial fibrillation in patients with heart failure: real-world results from the Cryo AF Global Registry

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.

OnBehalf

Cryo AF Global Registry Investigators

Background

Heart failure (HF) concomitant to atrial fibrillation (AF) can exacerbate the risk of hospitalization, morbidity, mortality, and impairment in quality of life posed by each condition alone. While the reciprocal relationship between HF and AF challenges effective treatment for these patients, catheter ablation for treatment of AF is reasonable for select patients with AF and HF according to guidelines. Purpose: Assess real-world usage and healthcare utilization outcomes of cryoablation for patients with AF and HF. Methods: The Cryo AF Global Registry (NCT02752737) is an ongoing, prospective, multicenter registry. Patients with AF were enrolled and treated with cryoballoon ablation (Arctic Front Advance, Medtronic) according to clinical practice at 56 sites in 26 countries world-wide. Subjects with NYHA class I-III at baseline comprised the HF cohort and were compared to patients without HF (No-HF). Freedom from atrial arrhythmia recurrence ≥30 sec, adverse events associated with the AF ablation procedure, repeat ablations, AAD usage, and cardiovascular rehospitalization over a 12-month follow-up were compared between cohorts. Results: A total of 1,303 patients (318 HF, 985 No-HF) were included. The HF cohort included patients with NYHA Class I (56.3%) and II/III (43.7%) with either preserved (81.6%) or mid/reduced (18.4%) left ventricular ejection fraction. HF patients were more often female (45.6% vs 33.6%) with persistent AF (25.8% vs 14.3%), larger left atrial diameter (4.4 ± 0.9 vs 4.0 ± 0.7 cm), and higher rates of hypertension (67.9% vs 49.1%) and prior myocardial infarction (3.8% vs 1.7%; all, P < 0.05). The rate of serious procedure-related complications was 5.3% in HF and 3.0% in No-HF (P = 0.08). Freedom from atrial arrhythmia recurrence at 12-months was not different between HF and No-HF patients with either paroxysmal (84.2% (95% CI:78.6-88.4) vs 86.8% (95% CI: 84.2 – 89.0)) or persistent AF (69.6% (95% CI: 58.1 – 78.5) vs 71.8% (95% CI: 63.2-78.7)), respectively (p = 0.32, HF vs No-HF). AF-related symptoms and antiarrhythmic drug use were significantly reduced after cryoablation in the HF and No-HF cohorts (P < 0.05). Freedom from repeat ablation at 12-months was similar between HF and No-HF patients. Of patients who had a cardiovascular rehospitalization after cryoablation, 78% presented with a supraventricular tachyarrhythmia. Persistent AF and HF at baseline both increased the risk of cardiovascular rehospitalization after cryoballoon ablation (P < 0.05). Conclusion: Cryoablation is used to treat patients with AF and concomitant HF in real-world practice and is similarly safe and effective at 12-months in patients with and without HF.

Anticoagulant treatment status and outcomes of elderly non-valvular atrial fibrillation patients with a history of catheter ablation in Japan: subanalysis of the ANAFIE registry

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Daiichi Sankyo Co., Ltd.

OnBehalf

ANAFIE Registry Group

Backgrounds

Benefits of catheter ablation (CA) have been shown for patients with atrial fibrillation (AF). However, data in elderly patients aged ≥75 years who have undergone CA for non-valvular AF (NVAF) are insufficient.

Purpose

The All Nippon Atrial Fibrillation In the Elderly (ANAFIE) Registry is a prospective, multicenter, observational study, which was designed to collect the real-world data on the clinical status and prognosis in 30,000 over Japanese patients (aged ≥75 years) with NVAF. This cross-sectional subanalysis of the ANAFIE registry assessed the 2-year outcomes and anticoagulant treatment in elderly NVAF patients with a history of CA.

Methods

A total of the 32,275 patients from the ANAFIE registry were divided into two groups by a history of CA: the CA and No-CA groups. Kaplan-Meier analysis was used to evaluate the annualized incidences of stroke/systemic embolic event (SEE), major bleeding, intracranial hemorrhage (ICH), heart failure requiring hospitalization (HF), and all-cause mortality. Hazard ratio (HR) for each event was analyzed using the Cox proportional-hazards model.

Results

Of all patients, 2,970 patients (9.2%) were included in the CA group and 29,305 (90.8%) were included in the No-CA group. The CA group had lower age (mean 78.9 vs 81.7 years), higher prevalence of paroxysmal AF (73.0 vs 39.0%), higher creatinine clearance (mean 53.1 vs 47.9 mL/min) and lower CHA2DS2-VASc (mean 4.2 vs 4.5) and HAS-BLED scores (mean 1.8 vs 1.9) than the No-CA group. Oral anticoagulants (OACs) were administered in 87.3% of the CA group (warfarin, 16.8%; direct OAC, 70.5%) and 92.9% of the No-CA group (warfarin, 26.4%; direct OAC, 66.5%). Compared with the No-CA group, the CA group had lower the annualized incidences (/100 patient-year [95%confidence intervals]) of stroke/SEE (0.74 [0.52, 0.96] vs 1.72 [1.61, 1.83]), major bleeding (0.63 [0.43, 0.84] vs 1.12 [1.03, 1.21]), ICH (0.49 [0.31, 0.67] vs 0.78 [0.71, 0.86]), HF (2.54 [2.12, 2.96] vs 4.44 [4.26, 4.62]), and all-cause mortality (1.45 [1.14, 1.77] vs 3.95 [3.78, 4.11]).

Conclusions

Elderly NVAF patients with a history of CA had lower adverse incidences compared with patients without a history of CA. A more optimal OAC therapy for elderly NVAF patients with a history of CA should be examined in the future.

Clinical implications of assessment of apixaban levels in elderly atrial fibrillation patients: J-ELD AF Registry sub-cohort analysis

Background

Randomized clinical trials demonstrated the efficacy and safety of apixaban in preventing stroke in patients with atrial fibrillation (AF). However, data on distribution of apixaban levels and their relationships with clinical outcomes are limited.

Purpose

To evaluate the distribution of blood apixaban concentration and its relationship with clinical outcomes.

Method

The J-ELD AF Registry is a large-scale, multicenter prospective observational study of Japanese non-valvular AF patients aged ≥75 years taking on-label dose (standard dose of 5 mg bid or reduced dose of 2.5 mg bid) of apixaban. Among the entire cohort (3,015 patients from 110 institutions), plasma apixaban levels at trough was measured by anti-Xa assay (Api-AXA) in 943 patients. The 943 patients were divided into 2 groups by the apixaban dose (standard dose [n=431] and reduced dose [n=512]) and each group was further divided into 2 groups with low and high Api-AXA levels compared with the median value.

Results

In patients with standard dose, the incidence rates (/100 person-years) of stroke or systemic embolism (1.48 and 1.99), bleeding requiring hospitalization (0.98 and 1.49), and total deaths (0.49 and 0.99) were comparable between low and high Api-AXA groups, respectively. In patients with reduced dose, although the incidence rates (/100 person-years) of stroke or systemic embolism (0.84 and 1.68) were comparable, bleeding requiring hospitalization (0.42 and 4.64), and total deaths (2.52 and 6.65) were significantly higher in high Api-AXA group than in low Api-AXA group. Multivariable Cox regression analysis revealed that in patients with reduced dose, high Api-AXA level was independently associated with bleeding requiring hospitalization (HR 12.12, 95% CI: 1.56–94.22, P=0.017) and insignificantly with total deaths (HR 2.15, 95% CI: 0.83–5.55, P=0.116).

Conclusions

High trough apixaban level in patients with standard dose was not associated with adverse events, while that in patients with reduced dose was associated with bleeding requiring hospitalization and total deaths. Measurement of apixaban levels may be informative in elderly patients indicated for reduced dose possibly with the intent of risk stratification and decision making.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Bristol-Myers Squibb K.K.

Impact of creatinine clearance on clinical outcomes in elderly atrial fibrillation patients receiving apixaban: J-ELD AF Registry sub-analysis

Background

Randomized clinical trials demonstrated the efficacy and safety of apixaban in preventing stroke in patients with atrial fibrillation (AF). However, data on patients with low creatinine clearance (CCr), especially CCr 15–29 mL/min, are limited.

Methods

The J-ELD AF Registry is a large-scale, multicenter prospective observational study of Japanese non-valvular AF patients aged ≥75 years taking on-label dose (standard dose of 5 mg bid or reduced dose of 2.5 mg bid) of apixaban. The enrollment period was from September 2015 to August 2016, and the observation period for each patient was 1 year. The entire cohort (3,015 patients from 110 institutions) was divided into three CCr subgroups: CCr ≥50 mL/min (n=1,165, 38.6%), CCr 30–49 mL/min (n=1,395, 46.3%), and CCr 15–29 mL/min (n=455, 15.1%).

Results

Most patients (74.3%) in the CCr ≥50 group received the standard apixaban dose, and most (97.4%) in the CCr 15–29 group received the reduced apixaban dose. The average age was 79.2 years for the CCr ≥50 group, 82.5 years for the CCr 30–49 group, and 85.6 years for the CCr 15–29 group. The lower CCr value group included more female patients, had lower body weight, and less cases of paroxysmal AF, as well as more cases of heart failure, peripheral artery disease, and myocardial infarction as comorbidities. The CHA2DS2-VASc and HAS-BLED scores were 4.2±1.2 and 2.4±0.8 for the CCr ≥50 group, 4.5±1.2 and 2.4±0.8 for the CCr 30–49 group, and 4.9±1.2 and 2.4±0.7 for the CCr 15–29 group, respectively. Kaplan Meier curves for cumulative incidence of events are shown in Figure. The event incidence rates (/100 person-years) were 1.76, 1.39, and 1.67 for stroke or systemic embolism (log rank p=0.762), 1.39, 1.93, and 3.13 for bleeding requiring hospitalization (log rank p=0.159), 1.75, 2.76, and 7.87 for total deaths (log rank p<0.001), and 0.46, 0.84, and 2.62 for cardiovascular deaths (log rank p<0.001), in the CCr ≥50 group, CCr 30–49 group, and CCr 15–29 group, respectively. After adjusting for confounders by Cox regression analysis, CCr 15–29 was an independent risk for total death [hazard ratio (HR) 3.22, 95% confidence interval (CI) 1.68–6.17, with reference to the CCr ≥50 group] and cardiovascular death [HR 3.18, 95% CI 1.06–9.56], but not for stroke or systemic embolism [HR 0.94, 95% CI 0.40–2.24], or bleeding requiring hospitalization [HR 2.00, 95% CI 0.93–4.28].

Conclusions

The incidence of events in each CCr value group was comparable for stroke or systemic embolism and bleeding requiring hospitalization, and significantly higher for total deaths and cardiovascular deaths only in the CCr 15–29 group, in Japanese non-valvular AF patients aged ≥75 years.

Cumulative incidence rates of events

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bristol-Myers Squibb

Sesamin suppresses aging phenotypes in adult muscular and nervous systems and intestines in a Drosophila senescence-accelerated model

OBJECTIVE

Sesamin is a major lignan constituent of sesame and possesses various health-promoting effects. Previous studies have demonstrated that sesamin extends the lifespan of Drosophila and Caenorhabditis elegans and corrects oxidative damage-related tissue dysfunction in mammals. To understand its anti-aging effects, we aimed to determine whether sesamin restores tissue function hampered by oxidative damage and suppresses several aging-related phenotypes using Drosophila senescence-accelerated models.

MATERIALS AND METHODS

We elucidated the anti-aging effects of sesamin on several aging-related phenotypes in the muscle, brain and midgut using the senescence-accelerated models (Sod1n1 mutant and Sod1-depleted flies) by immunostaining experiments. We determined the expression levels of several anti-oxidative and DNA repair genes using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). We also identified the metabolite of sesamin in Drosophila by LC-MS/MS.

RESULTS

We confirmed that sesamin (0.35 and 2 mg/ml) extended the lifespan of the fly models. As observed in mammals, it can be absorbed and metabolized by Drosophila adults. The sesamin feeding suppressed the age-dependent impairment of locomotor activity and inhibited the accumulation of reactive oxygen species (ROS) in their bodies. Sesamin delayed the age-dependent accumulation of damaged proteins in the muscle, partially suppressed the loss of dopaminergic neurons in adult brains displaying ROS accumulation, and suppressed the accumulation of DNA damage and hyperproliferation of intestinal stem cells. Four antioxidative genes and two DNA repair genes were simultaneously upregulated in sesamin-fed adults.  CONCLUSIONS: These observations represent the first direct evidence of the anti-aging effects of sesamin at the individual level. We propose that sesamin exerts anti-aging effects in the muscles, brain and midgut by inducing antioxidative and DNA repair genes, resulting in extended lifespan in flies.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

P3755Left atrial enlargement as an independent risk factor for ischemic stroke in Japanese atrial fibrillation patients: pooled analysis of five major Japanese atrial fibrillation registries

Background

Atrial fibrillation (AF) increases the risk of ischemic stroke. It remains unknown whether left atrial diameter determined by routine trans-thoracic echocardiography is a risk factor for ischemic stroke in non-valvular AF (NVAF) patients.

Purpose

The aim of this study is to investigate the impact of left atrial enlargement (LAE) on the incidence of ischemic stroke in a large-scale cohort of Japanese NVAF patients.

Methods

We combined the data of 5 major AF registries in Japan, J-RHYTHM Registry, Fushimi AF Registry, Shinken Database, Keio interhospital Cardiovascular Studies, and Hokuriku AF Registry. After excluding patients without echocardiographic data, 7,672 NVAF patients were analyzed in the present study (mean age, 69.3±12.3 years; mean CHADS2 score, 1.6±1.3). We compared clinical characteristics and the incidence of ischemic stroke between NVAF patients with LAE (left atrial diameter >45 mm; LAE group) and those without (non-LAE group).

Results

The mean left atrial diameter was 43.1±8.6 mm, and the LAE group accounted for 40.0% (n=3,066) of the entire cohort. Compared with non-LAE group (60.0%, n=4,606), the LAE group was older (LAE vs. non-LAE; 70.3±12.0 vs. 68.0±12.5, p<0.01), more often non-paroxysmal type (73.7% vs. 32.1%, p<0.01), had higher CHADS2 (1.86±1.34 vs. 1.46±1.29, p<0.01) and CHA2DS2-VASc (3.02±1.83 vs. 2.53±1.78, p<0.01) scores, and more frequently received oral anticoagulant (72.9% vs. 55.0%, p<0.01).

During the median follow-up period of 774.5 days (interquartile range: 567–1466 days), ischemic stroke occurred in 241 patients (131 vs. 110 patients; 1.52 vs. 0.82 per 100 person-years). In Kaplan Meier analysis, LAE was associated with a higher incidence of ischemic stroke (unadjusted hazard ratio (HR): 1.83, 95% confidence interval (CI): 1.42–2.36; log rank p<0.01) (Figure). LAE was independently associated with increased risk of ischemic stroke (adjusted HR: 1.63, 95% CI: 1.25–2.11; p<0.01) after adjustment by the components of CHADS2 score and the use of oral anticoagulant, on multivariate Cox proportional hazard analysis.

Conclusion

In this large-scale cohort of Japanese patients with AF, LAE was an independent predictor of ischemic stroke, suggesting that this simple echocardiographic parameter could refine thromboembolic risk stratification of NVAF patients.

Acknowledgement/Funding

Japan Agency for Medical Research and Development, AMED

457Efficacy and safety of uninterrupted periprocedural edoxaban in patients undergoing catheter ablation for atrial fibrillation: Prospective KYU-RABLE study

Background/Introduction

Catheter ablation (CA) has been established as a first-line therapy in the treatment of non-valvular atrial fibrillation (NVAF), and uninterrupted direct oral anticoagulants (DOACs) have become mainstream for the management of periprocedural thromboembolic events. Since 2014, edoxaban has been used for anticoagulation therapy for AF in Japan. However, evidence for uninterrupted use of edoxaban during the periprocedural period of CA in NVAF patients is limited.

Purpose

KYU-RABLE is a prospective, multicenter, single-arm interventional study, conducted in 23 institutions in Japan to evaluate the efficacy and safety of uninterrupted periprocedural oral edoxaban in patients undergoing CA. The plasma concentration of edoxaban and its relation with plasma coagulative biomarker levels during the periprocedural period were also evaluated.

Methods

A total of 537 Japanese NVAF patients were enrolled in Japan from December 2017 to September 2018. Edoxaban 60mg (30 mg in patients indicated for dose adjustment) was administered once daily in the morning for at least 4 weeks before CA and continued for at least 4 weeks after CA. On the day of CA, edoxaban was administered immediately after confirmation of hemostat. The primary endpoint was the composite incidence of thromboembolism and major bleeding events during 4 weeks from the procedural day. Plasma concentration of edoxaban and plasma levels of coagulative biomarkers including D-dimer, soluble fibrin monomer complex (SFMC) and prothrombin fragment 1+2 (F1+2) were also measured.

Results

Among the total 513 patients who underwent CA, 75.2% had radiofrequency CA and 23.0% had cryoballoon CA. The majority of CA patients (65%) received edoxaban 60mg/day, while others (35%) received 30mg/day. As for the primary endpoint, one major bleeding (cardiac tamponade) event was observed and no thromboembolism occurred. Clinically relevant non-major bleeding events occurred in six patients (1.2%), the most were puncture site hemorrhage. The plasma concentration of edoxaban at CA was dependent upon the duration from last administration of edoxaban before CA. However, plasma levels of coagulative biomarkers (D-dimer, SFMC, F1+2) were maintained within appropriate range during the periprocedural period, irrespective of the edoxaban concentration. We also report changes of plasma levels of coagulative biomarkers in sub group analyses by CHADS2 scores and types of AF.

Conclusion

The KYU-RABLE study demonstrated the first evidence of the efficacy and safety of uninterrupted periprocedural edoxaban administered once daily on the morning for NVAF patients underwent CA. Edoxaban treatment was associated with a low risk of periprocedural bleeding and thromboembolic complications. Furthermore, these low event risks were considered to be associated with the maintained plasma level of coagulative biomarkers, regardless of the change in edoxaban plasma concentration.

Acknowledgement/Funding

Daiichi Sankyo Co. Ltd.

P5668A decision-support tool framework to predict adverse outcome in patients with atrial fibrillation: J-Rhythm registry substudy

Background

Atrial fibrillation (AF) is associated with increased mortality and morbidity. Modelling the risk of thrombosis, major bleeding and total mortality are often limited by the inadequate number of independent predictors.

Purpose

We compared the predictive accuracy of the decision-support tool framework and conventional risk score in AF patients.

Methods

We used data of AF patients enrolled into the nationwide AF registry. A random forest model was implemented to predict each outcome, and its predictive power was tested by a 5-fold cross-validation.

Results

We analyzed 7,937 patients with AF (age 70±10 years, female 31%). The type of AF was paroxysmal (37%), persistent (14%), and permanent (49%). The number of antithrombotic treatments were follows: warfarin only (n=5461), antiplatelet only (n=581), both warfarin and antiplatelet (n=1471) and no antithrombotic agents (424). The mean CHA2DS2-VASc score was 2.8±1.6 and HAS-BLED score was 2.7±1.2, respectively. We selected 20 from 50 clinical parameters and compared by the area-under-curve with the CHA2DS2-VASc score for thromboses and the HAS-BLED score for major bleeding. During the 2-year follow-up, 126 patients (1.6%) had thromboses, 140 (1.8%) had major bleeding, and 195 (2.5%) died. A random forest model had a higher value of the area-under-curve for predicting thromboses compared with the CHA2DS2-VASc (0.66 vs. 0.61, P<0.05), and had a significantly higher area-under-curve for major bleeding compared with the HAS-BLED (0.67 vs. 0.61, P<0.05). The area-under-curve for the all-cause mortality was 0.77.

Conclusions

A random forest model has a higher accuracy than conventional risk scheme in predicting thromboses and major bleeding, in addition to total mortality.

P1865Incidence and predictors of invasively-treated pericardial effusion during catheter ablation of atrial fibrillation in Japan

Purpose and method

Japanese Heart Rhythm Society requested electrophysiology centers to register the data of patients who underwent catheter ablation for atrial fibrillation (AF) in designated eight months from 2011 to 2017. We assessed the incidence and predictors of pericardial effusion (PE) as an early complication of AF ablation.

Results

More than two hundred EP centers reported the data of 13,233 AF ablation cases (age; 64.2±10.7 years, male; 72.6%, paroxysmal AF; 63.4%). Clinically significant complications occurred in 601 subjects (4.5%). Critical PE occurred in 116 patients (0.8%), while six of them required open-chest surgery. Overall complication rate did not show significant changes. In contrast, incidence of PE declined over time (2012:1.2%, 2017:0.5%, p=0.003). Multiple logistic regression analysis showed that seven factors were related with higher incidence of PE. Among these factors, primary extra-PV ablation and hypertrophic cardiomyopathy (HCM) were more remarkably associated with higher rate of PE (PVI[−] vs. PVI[+]= 9.0% vs. 0.8%, OR 12.3, p<0.001; HCM: [+] vs. [−] = 2.6% vs. 0.8%, OR 3.26, p=0.001). Comorbidity of coronary artery disease (CAD) and use of CARTO system were related with lower PE rate (CAD: [+] vs [−] = 0.2% vs. 0.9%, OR 0.22 [p=0.034], CARTO: [+] vs [−] = 0.7% vs. 1.2%, OR 0.52 [p=0.001]). None of cryobaloon ablation, gender, type of AF, center volume, periprocedural oral anticoagulant, or left atrial diameter was significantly related with the occurrence of PE.

Conclusions

Incidence of critical PE decreased recently. HCM and primary extra-PV ablation were outstanding predictors of critical PE.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Search for Boosted Dark Matter Interacting with Electrons in Super-Kamiokande

A search for boosted dark matter using 161.9 kt yr of Super-Kamiokande IV data is presented. We search for an excess of elastically scattered electrons above the atmospheric neutrino background, with a visible energy between 100 MeV and 1 TeV, pointing back to the Galactic center or the Sun. No such excess is observed. Limits on boosted dark matter event rates in multiple angular cones around the Galactic center and Sun are calculated. Limits are also calculated for a baseline model of boosted dark matter produced from cold dark matter annihilation or decay. This is the first experimental search for boosted dark matter from the Galactic center or the Sun interacting in a terrestrial detector.

A Remote-operated System to Map Radiation Dose in the Fukushima Daiichi Primary Containment Vessel

This paper describes the development of a submersible system based on a remote-operated vehicle coupled with radiation detectors to map the interior of the reactors at the Fukushima Daiichi nuclear power station. It has the aim oflocating fuel debris. The AVEXIS submersible vehicle used in this study has been designed as a low-cost, potentially disposable, inspection platform that is the smallest of its class and is capable of being deployed through a 150 mm diameter access pipe. To map the gamma-ray environment, a cerium bromide scintillator detector with a small form factor has been incorporated into the AVEXIS to identify radioactive isotopes via gamma-ray spectroscopy. This provides the combined system with the potential to map gamma-ray spectra and particle locations throughout submerged, contaminated facilities, such as Units 1, 2 and 3 of the Fukushima Daiichi nuclear power plant. The hypothesis of this research is to determine the sensitivity of the combined system in a submerged environment that replicates the combination of gamma radiation and water submersion but at lower dose rates.

Combined Analysis of Neutrino and Antineutrino Oscillations at T2K

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135  μ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66  μ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{μ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{μ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{μ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained μ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3}  eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3}  eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{μ} disappearance parameters measured by T2K.

Search for Nucleon and Dinucleon Decays with an Invisible Particle and a Charged Lepton in the Final State at the Super-Kamiokande Experiment

Search results for nucleon decays p→e^{+}X, p→μ^{+}X, n→νγ (where X is an invisible, massless particle) as well as dinucleon decays np→e^{+}ν, np→μ^{+}ν, and np→τ^{+}ν in the Super-Kamiokande experiment are presented. Using single-ring data from an exposure of  273.4  kton·yr, a search for these decays yields a result consistent with no signal. Accordingly, lower limits on the partial lifetimes of τ_{p→e^{+}X}>7.9×10^{32} yr, τ_{p→μ^{+}X}>4.1×10^{32} yr, τ_{n→νγ}>5.5×10^{32} yr, τ_{np→e^{+}ν}>2.6×10^{32}  yr, τ_{np→μ^{+}ν}>2.2×10^{32} yr, and τ_{np→τ^{+}ν}>2.9×10^{31} yr at a 90% confidence level are obtained. Some of these searches are novel.