Tracing Photoinduced Hydrogen Migration in Alcohol Dications from Time-Resolved Molecular-Frame Photoelectron Angular Distributions

The recent implementation of attosecond and few-femtosecond X-ray pump/X-ray probe schemes in large-scale free-electron laser facilities has opened the way to visualize fast nuclear dynamics in molecules with unprecedented temporal and spatial resolution. Here, we present the results of theoretical calculations showing how polarization-averaged molecular-frame photoelectron angular distributions (PA-MFPADs) can be used to visualize the dynamics of hydrogen migration in methanol, ethanol, propanol, and isopropyl alcohol dications generated by X-ray irradiation of the corresponding neutral species. We show that changes in the PA-MFPADs with the pump-probe delay as a result of intramolecular photoelectron diffraction carry information on the dynamics of hydrogen migration in real space. Although visualization of this dynamics is more straightforward in the smaller systems, methanol and ethanol, one can still recognize the signature of that motion in propanol and isopropyl alcohol and assign a tentative path to it. A possible pathway for a corresponding experiment requires an angularly resolved detection of photoelectrons in coincidence with molecular fragment ions used to define a molecular frame of reference. Such studies have become, in principle, possible since the first XFELs with sufficiently high repetition rates have emerged. To further support our findings, we provide experimental evidence of H migration in ethanol-OD from ion-ion coincidence measurements performed with synchrotron radiation.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Expanded adaptation of an artificial intelligence model for predicting chemotherapy-induced cardiotoxicity using baseline electrocardiograms

Introduction

While effective as chemotherapeutics, anthracyclines can cause cancer therapy-related cardiac dysfunction (CTRCD), which adversely affects the prognosis of patients with malignancies1–5. Despite guideline recommendations6–9, repeated echocardiograms are rarely performed10 with delayed diagnosis of CTRCD leading to unrecoverable cardiac dysfunction11. Recently, artificial intelligence (AI) was shown to be capable of detecting reduced left ventricular ejection fraction (LVEF) solely from electrocardiogram (ECG)12. Furthermore, this model was predictive of a future decrease in LVEF. Therefore, we hypothesized that an AI model detecting reduced LVEF (AI-EF model) could predict CTRCD from ECGs.

Purpose

To assess whether the AI-EF model could detect patients at a high risk of CTRCD by analyzing ECGs taken immediately prior to the initiation of cardiotoxic chemotherapy.

Methods

Among patients who received chemotherapy with a regimen including anthracyclines in two institutions between June 1st, 2015 and October 1st, 2020, those who underwent both an ECG and echocardiogram ≤90 days prior to initial treatment were selected. The ECGs were analyzed by the AI-EF model and patients were divided into two groups according to the scores from the model. CTRCD was defined as LVEF &lt;53% and ≥10% decrease in LVEF from the baseline at any time after the start of chemotherapy13. The cumulative incidence of CTRCD was compared for the two groups using Kaplan-Meier curves, log-rank test, a univariate Cox proportional hazard model, and a multivariable Cox proportional hazard model adjusting for known risk factors for CTRCD. Finally, a prediction model for CTRCD using readily available clinical variables with the AI-EF score was compared with the model using the same variables without the AI-EF score.

Results

1,158 patients were included in this study. 99 of them developed CTRCD during follow-up. The AI-EF model displayed excellent risk stratification of developing CTRCD: while 7.1% in the low AI-EF score group developed CTRCD, 12.9% of the patients in the high AI-EF score group developed CTRCD (hazard ratio (HR), 2.14; 95% confidence interval (CI), 1.43–3.19; log-rank p&lt;0.001; Figure 1). This finding was robust across subgroups such as cancer types, the initial dose of anthracycline and baseline LVEF, and consistent after adjusting for multiple risk factors (adjusted HR, 2.10; 95% CI, 1.37–3.22; p&lt;0.001; Figure 2). Furthermore, the addition of the AI-EF score significantly improved the accuracy of predicting CTRCD compared to clinical features alone (time-dependent area under the received operating curve (AUROC) for 2 years, 77.1; 95% CI, 71.8–82.3 for the model with AI-EF score and AUROC 73.9; 95% CI, 69.0–80.1 for the model without AI-EF score; p=0.02).

Conclusion

The AI-EF model, by utilizing baseline ECG, could stratify patients according to the risk of CTRCD and robustly augmented CTRCD prediction.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): American Heart AssociationVerily

Rhythm versus rate control in patients with newly diagnosed atrial fibrillation: observations from the GARFIELD-AF registry

Background

Atrial fibrillation is associated with considerable morbidity and mortality. Real-world reports on the effect of early rhythm control on patient outcomes in patient with recent onset atrial fibrillation are limited.

Purpose

To assess the effect of early rhythm versus rate control on clinical outcomes in patients with newly diagnosed non-valvular atrial fibrillation.

Method

The Global Anticoagulant Registry in the FIELD-AF (GARFIELD-AF) is a non-interventional registry of adult (≥18 years) patients with newly diagnosed atrial fibrillation (≤ six weeks' duration) and at least one investigator determined risk factor for stroke. Patients were enrolled in 1317 participating sites in 35 countries between March 2010 and August 2016. Patients with permanent atrial fibrillation were excluded. Stratification to rhythm or rate control was based on treatment strategy initiated at baseline (≤48 days post enrolment). Rhythm control was defined as investigator reported initiation of rhythm control (antiarrhythmic drug(s), cardioversion, or ablation – alone or in combination with rate modifiers). Rate control was defined as investigator reported initiation of rate control and absence of rhythm control therapy. Overlap propensity weighting and Cox proportional-hazards models were used to evaluate effect on outcomes.

Results

Of 45,382 included patients, 23,858 (52.6%) received rhythm control and 21,524 (47.4%) rate control. Rates of rhythm control were similar throughout the study time period (52.7% in 2010/2011, 54.2% in 2015/2016). Patients in the rhythm control group were younger (median age (Q1; Q3) 68.0 (60.0; 76.0) versus 73.0 (65.0; 79.0)), had lower rates of prior stroke/transitory ischemic attack/systemic embolism (9.4% vs 13.0%), and a lower median GARFIELD death score (4.0 (2.3; 7.5) versus 5.1 (2.8; 9.2)). Median CHA2DS2-VASc Scores were 3.0 (2.0; 4.0) in both groups. Rate of anticoagulation treatment was similar in the rhythm and rate control group (66.0% versus 65.5%). After propensity score overlap weighting, patients of the two groups were well balanced on all observed characteristics.

Event rates per 100 person-years (95% confidence interval [CI]) over two years follow-up in the rhythm and rate control group were 2.94 (2.78–3.10) versus 4.43 (4.22–4.64) for mortality, 0.84 (0.75–0.92) versus 1.16 (1.05–1.27) for non-haemorrhagic stroke/systemic embolism and 0.84 (0.76–0.93) versus 1.16 (1.06–1.27) for major bleeding. Adjusted hazard ratios (95% CI) for the same time period were 0.85 (0.79–0.92), 0.84 (0.72–0.97) and 0.9 (0.78–1.04).

Conclusion

In this large, internation registry, a rhythm control strategy was initiated at baseline in about half of the patients with newly diagnosed non-valvular atrial fibrillation. After adjustment for confounding factors, a significantly lower risk of all-cause mortality and non-haemorrhagic stroke/systemic embolism were observed for patients that received an early rhythm control strategy.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by the Thrombosis Research Institute (London, UK).

O-301 Genome-wide association study identified meiotic variant associated with aneuploid pregnancy loss

Study question

Which single nucleotide variant (SNVs) are associated with aneuploid pregnancy loss?

Summary answer

We identified a SNV on MEIG1 gene, which are associated with meiosis/spermiogenesis.

What is known already

Recurrent pregnancy loss (RPL) refers to the loss of two or more pregnancies, with a frequency of 5%. Chromosomal abnormalities in embryos are found in 80% of first trimester miscarriages, 86% of which are aneuploid. Recently, embryonic aneuploidy was found to be the most common cause of RPL, with a frequency of 40-50%. Most trisomy miscarriages are of maternal origin, with errors occurring during meiosis of the oocyte. Chromosome segregation abnormalities in oocytes are thought to be an event associated with increasing maternal age, but in addition, maternal genetic causes are thought to contribute.

Study design, size, duration

A Genome wide association study (GWAS) was performed on a clinically well characterized cohort of 189 women with RPL whose previous aborted conceptus was ascertained to be an aneuploid embryo. Samples were mainly collected from 2007 to 2018 mainly at Nagoya City University Hospital. For control samples, we used 1157 samples from the population-based prospective cohorts that included fertile women.

Participants/materials, setting, methods

All patients underwent a systematic examination. Patients with antiphospholipid syndrome, an abnormal chromosome in either partner, or uterine anomaly were excluded. Patients whose previously miscarried POC exhibited triploidy or 45, X were excluded. DNA was isolated from stored EDTA-blood samples and genotyped by Axiom Japonica-array v2659,503 SNVs). For the GWAS, a chi-squared test was applied to a two-by-two contingency table in allele frequency model.

Main results and the role of chance

The mean (SD) ages and number of previous miscarriages of the patients were 36.8 (4.3) and 3.09 (1.13). GWAS data revealed 5 SNVs with suggestive significance (p &lt; 9.46e-06). The SNVs that showed the most significant associations (P = 1.06E-06, OR = 1.72) was located on meiosis/spermiogenesis associated 1 (MEIG1) gene under an allelic model after Bonferroni correction considering the number of analyzed SNVs. The SNV rs7908491 was reported as a splicing QTL in the MEIG1 gene, which is a meiosis/meiosis-associated factor and is plausibly associated with chromosome aneuploidy. This is the first GWAS in patients with RPL caused by aneuploidy.

Limitations, reasons for caution

Since this study was conducted in a single center and had a small sample size, it needs to be replicated in different centers with more subjects and on an international scale. Whole genome imputation analysis will be performed to detect SNVs with more significant associations.

Wider implications of the findings

Our findings demonstrate that a specific genotype of MEIG1 gene can be a risk factor for aneuploid pregnancy loss. The establishment of clinically applicable maternal germ cell markers could identify groups for whom PGT would be more useful or provide patients with counseling that provides prognostic information about pregnancy.

Trial registration number

not applicable

Long-term safety and efficacy of anacetrapib in patients with atherosclerotic vascular disease

AIMS

REVEAL was the first randomized controlled trial to demonstrate that adding cholesteryl ester transfer protein inhibitor therapy to intensive statin therapy reduced the risk of major coronary events. We now report results from extended follow-up beyond the scheduled study treatment period.

METHODS AND RESULTS

A total of 30 449 adults with prior atherosclerotic vascular disease were randomly allocated to anacetrapib 100 mg daily or matching placebo, in addition to open-label atorvastatin therapy. After stopping the randomly allocated treatment, 26 129 survivors entered a post-trial follow-up period, blind to their original treatment allocation. The primary outcome was first post-randomization major coronary event (i.e. coronary death, myocardial infarction, or coronary revascularization) during the in-trial and post-trial treatment periods, with analysis by intention-to-treat. Allocation to anacetrapib conferred a 9% [95% confidence interval (CI) 3-15%; P = 0.004] proportional reduction in the incidence of major coronary events during the study treatment period (median 4.1 years). During extended follow-up (median 2.2 years), there was a further 20% (95% CI 10-29%; P < 0.001) reduction. Overall, there was a 12% (95% CI 7-17%, P < 0.001) proportional reduction in major coronary events during the overall follow-up period (median 6.3 years), corresponding to a 1.8% (95% CI 1.0-2.6%) absolute reduction. There were no significant effects on non-vascular mortality, site-specific cancer, or other serious adverse events. Morbidity follow-up was obtained for 25 784 (99%) participants.

CONCLUSION

The beneficial effects of anacetrapib on major coronary events increased with longer follow-up, and no adverse effects emerged on non-vascular mortality or morbidity. These findings illustrate the importance of sufficiently long treatment and follow-up duration in randomized trials of lipid-modifying agents to assess their full benefits and potential harms.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial Number (ISRCTN) 48678192; ClinicalTrials.gov No. NCT01252953; EudraCT No. 2010-023467-18.

Comparative effectiveness of NOAC vs VKA in patients representing common clinical challenges: results from the GARFIELD-AF registry

Introduction

Large phase III trials of non-valvular atrial fibrillation (AF) patients have shown a favourable risk-to-benefit ratio with Non-Vitamin K antagonist oral anticoagulants (NOAC) compared to Vitamin K antagonists (VKA). Although the results of these trials are directly applicable to many AF patients, important subsets of patients were under-represented. Thus, there remains uncertainty about the safety and effectiveness of NOAC therapy in common challenging scenarios.

Purpose

The main purpose of this study is to quantify and compare the impact of NOAC vs VKA in settings where clinical uncertainty still exists and represents a considerable proportion of AF patients in clinical practice.

Methods

The analysis was conducted in patients enrolled in the largest AF multinational prospective registry (the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation, GARFIELD-AF). We evaluated the effectiveness and safety of NOAC compared to VKA in three groups of patients representing common clinical challenges (CCC): 1) elderly patients (i.e. age ≥75), 2) increased bleeding risk (i.e. HAS-BLED ≥3 or prior bleeding), and 3) renal impairment (i.e. CKD stages II to IV).

We applied a propensity score using an overlap weighting scheme to obtain unbiased estimates of the treatment effect within each CCC group. Weights were applied to Cox proportional hazards models to estimate the effects of the NOAC vs VKA comparison on the occurrence of death, non-haemorrhagic stroke/SE and major bleeding within 2 years of enrolment.

Results

Comparative effectiveness of NOAC vs VKA was assessed in 8607 elderly patients, 1711 with increased bleeding risk, and 4460 with renal impairment.

The proportion of anticoagulated patients was low in patients with increased bleeding risk (59%), while in the other two CCC groups the corresponding proportion was close to the one in the overall population (72%).

Among anticoagulated patients, NOAC were prescribed to 50–55% of patients in the CCC groups. Patients with a high risk of bleeding and impaired kidney function were less likely to be prescribed NOAC instead of VKA compared with the overall anticoagulated population (−5.4% and −4.7%, respectively).

Propensity-weighted hazard ratios for all-cause mortality favored NOAC (vs VKA) in all three CCC groups: 0.86 (95% CI: 0.74–0.99) for elderly patients, 0.73 (0.53–1.00) for patients with increased bleeding risk, and 0.80 (0.65–0.98) for patients with renal impairment (Figure).

Conclusion

In the selected common challenging scenarios of AF patients, there were significant mortality reductions in favor of NOACs compared to VKAs. These observations suggest that NOACs are safe and effective in patients who are elderly, at increased bleeding risk, or renally impaired.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This study was supported by an unrestricted research grant from Bayer AG, Berlin, Germany, to TRI, London, UK, which sponsors the GARFIELD-AF registry. The work is supported by KANTOR CHARITABLE FOUNDATION for the Kantor-Kakkar Global Centre for Thrombosis Science.

Safety and efficacy of apixaban and rivaroxaban versus warfarin in real-world atrial fibrillation patients are similar to their randomized trials: insights from GARFIELD-AF registry

Introduction

Generalisability of patient selection in the landmark trials for the approval of apixaban (ARISTOTLE) and rivaroxaban (ROCKET AF) for use in non-valvular atrial fibrillation (AF) is limited. Although observational data have confirmed the safety and efficacy of these non-vitamin K oral anticoagulants (NOACs) in unselected AF populations, robust replication of randomized trials in observational studies is warranted.

Purpose

To investigate the proportion of real-world AF patients who would have been eligible for the landmark trials for ARISTOTLE and ROCKET AF, and to assess reproducibility of these landmark trials in the largest, worldwide, prospective registry of newly diagnosed AF patients.

Methods

We analysed data from the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation (GARFIELD-AF) registry. We assessed the eligibility of AF patients treated with apixaban or vitamin K antagonist (VKA) for ARISTOTLE, and those treated with rivaroxaban or VKA for ROCKET AF, using the selection criteria of the original trials. We replicated the inclusion and exclusion criteria of ARISTOTLE and ROCKET AF by deriving the set of patients eligible for each trial and calculating the adjusted hazard ratios (HRs) for stroke or systemic embolism, major bleeding, and all-cause mortality within 2 years of enrolment, using a propensity score overlap weighted Cox model. We compared the results from observational data with those reported in the original ARISTOTLE and ROCKET AF publications.

Results

Among all patients enrolled in GARFIELD-AF, 67% were eligible for recruitment in ARISTOTLE and 37% in ROCKET AF. The corresponding proportions among anticoagulated patients were 70% and 39%, respectively. Among patients on apixaban and VKA, 2570/3615 (71%) and 8005/11718 (68%), respectively, were eligible for ARISTOTLE. Of patients using rivaroxaban and VKA, 2005/4914 (41%) and 4368/11721 (37%), respectively, were eligible for ROCKET AF. Annual eligibility rates among real-world NOAC users were stable over time (Figure 1). Registry participants on rivaroxaban or VKA eligible for ROCKET AF had a higher burden of cardiovascular co-morbidity than those on apixaban or VKA eligible for ARISTOTLE. The adjusted HRs in observational data were compatible with results of the original trials in all selected outcomes (Figure 2).

Conclusion

Representativeness of ARISTOTLE and ROCKET AF for real-world AF populations was limited, with ROCKET AF's criteria being more restrictive. Despite inclusion of only incident AF cases in GARFIELD-AF versus mostly prevalent AF cases in the original trials, the results were similar. Our work indicates that the results from ARISTOTLE and ROCKET AF appear robust and reproducible in real-world patients with newly diagnosed AF.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by an unrestricted research grant from Bayer AG, Berlin, Germany, to TRI, London, UK, which sponsors the GARFIELD-AF registry. This work is supported by KANTOR CHARITABLE FOUNDATION for the Kantor-Kakkar Global Centre for Thrombosis Science.

Comparing rivaroxaban and apixaban in GARFIELD-AF according to ROCKET AF and ARISTOTLE trial selection criteria

Introduction

There is debate on the extent to which differences in selection criteria and outcome definitions used for ARISTOTLE and ROCKET AF – the trials for the approval of apixaban and rivaroxaban, respectively, for non-valvular atrial fibrillation – influenced their differences in outcomes relative to vitamin K antagonists (VKAs). In absence of randomized trials comparing the two non-vitamin K oral antagonists (NOACs) directly, this question can be addressed using data from the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation (GARFIELD-AF) registry, a large, high-quality prospective observational study of newly diagnosed AF patients.

Purpose

To assess the influence of the ARISTOTLE and ROCKET AF inclusion and exclusion criteria on results for safety and efficacy of apixaban and rivaroxaban versus VKA using uniform endpoints in GARFIELD-AF.

Methods

We selected patients treated with apixaban, rivaroxaban or VKA from GARFIELD-AF who were eligible for ARISTOTLE or ROCKET AF as per the original trial criteria. We replicated the inclusion criteria in the GARFIELD-AF population and derived those eligible for each trial. We calculated the adjusted hazard ratios (HRs) for stroke or systemic embolism, major bleeding and all-cause mortality within 2 years of enrolment for apixaban as well as rivaroxaban versus VKA (reference) in those eligible for each trial. We used a propensity score overlap weighted Cox model to emulate trial randomization between NOAC and VKA.

Results

Among patients on apixaban, rivaroxaban and VKA, 2570/3615 (71%), 3560/4914 (72%) and 8005/11734 (71%) were eligible for ARISTOTLE, respectively, and 1612/3615 (45%), 2005/4914 (41%) and 4368/11734 (37%), respectively, were eligible for ROCKET AF. Cardiovascular co-morbidity was greater in those eligible for ROCKET AF than in those eligible for ARISTOTLE. In patients selected using the more restrictive ROCKET AF criteria, apixaban and rivaroxaban users showed similar results when compared with VKA (see Figure). The two sets of comparisons remained non-significant in difference when applying the less restrictive ARISTOTLE criteria, but there were trends for less similarity.

Conclusion

Apixaban showed similar results to rivaroxaban when selecting for higher-risk patients using the ROCKET AF criteria. In patients selected using ARISTOTLE criteria the similarity was less pronounced. Our results underline the problems faced in comparing treatments across rather than within clinical trials. For instance, co-morbidities were substantially different for patients recruited into the original ARISTOTLE and ROCKET AF trials. The current work points to the need for high-quality observational data for assessment of relative drug performance in absence of direct drug comparisons through randomized trials.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by an unrestricted research grant from Bayer AG, Berlin, Germany, to TRI, London, UK, which sponsors the GARFIELD-AF registry. This work is supported by KANTOR CHARITABLE FOUNDATION for the Kantor-Kakkar Global Centre for Thrombosis Science.

P–377 Association between antinuclear antibodies and pregnancy prognosis in recurrent pregnancy loss patients

Study question

Can antinuclear antibody (ANA) affect the subsequent live birth rate in patients with recurrent pregnancy loss (RPL) who have no antiphospholipid antibodies (aPLs)?

Summary answer

ANA did not affect the pregnancy prognosis of RPL women.

What is known already

The prevalence of ANA is well-known to be higher in RPL patients. Our previous study found no difference in the live birth rates of ANA-positive and -negative patients who had no aPLs. Higher miscarriage rates were also reported in ANA-positive patients compared to ANA-negative patients with RPL. The RPL guidelines of the ESHRE state that “ANA testing can be considered for explanatory purposes.” However, there have been a limited number of studies on this issue and sample sizes have been small, and the impact of ANA on the pregnancy prognosis is unclear.

Study design, size, duration

An observational cohort study was conducted at Nagoya City University Hospital between 2006 and 2019. The study included 1,108 patients with a history of 2 or more pregnancy losses.

Participants/materials, setting, methods

4D-Ultrasound, hysterosalpingography, chromosome analysis for both partners, aPLs and blood tests for ANA and diabetes mellitus were performed before a subsequent pregnancy. ANAs were measured by indirect immunofluorescence. The cutoff dilution used was 1:40. In addition, patients were classified according to the ANA pattern on immunofluorescence staining. Live birth rates were compared between ANA-positive and ANA-negative patients after excluding patients with antiphospholipid syndrome, an abnormal chromosome in either partner and a uterine anomaly.

Main results and the role of chance

The 994 patients were analyzed after excluding 40 with a uterine anomaly, 43 with a chromosome abnormality in either partner and 32 with APS. The rate of ANA-positive patients was 39.2% (390/994) when the 1: 40 dilution result was positive. With a 1:160 dilution, the rate of ANA-positive patients was 3.62% (36/994). The live birth rate was calculated for 798 patients, excluding 196 patients with unexplained RPL who had been treated with any medication.

With the use of the 1: 40 dilution, the subsequent live birth rates were 71.34% (219/307) for the ANA-positive group and 70.67% (347/491) for the ANA-negative group (OR, 95%CI; 0.968, 0.707–1.326). After excluding miscarriages with embryonic aneuploidy, chemical pregnancies and ectopic pregnancies, live birth rates were 92.41% (219/237) for the ANA-positive group and 92.04% (347/377) for the ANA-negative group (0.951, 0.517–1.747). Using the 1:160 dilution, the subsequent live birth rates were 84.62% (22/26) for the ANA-positive group, and 70.47% (544/772) for the ANA-negative group (0.434, 0.148–1.273).

Subgroup analyses were performed for each pattern on immunofluorescence staining, but there was no significant difference in the live birth rate between the two groups.

Limitations, reasons for caution

The effectiveness of immunotherapies could not be evaluated. However, the results of this study suggest that it is not necessary.

Wider implications of the findings: The measurement of ANA might not be necessary for the screening of patients with RPL who have no features of collagen disease.

Trial registration number

Not applicable

P-377 Association between antinuclear antibodies and pregnancy prognosis in recurrent pregnancy loss patients

Study question

Can antinuclear antibody (ANA) affect the subsequent live birth rate in patients with recurrent pregnancy loss (RPL) who have no antiphospholipid antibodies (aPLs)?

Summary answer

ANA did not affect the pregnancy prognosis of RPL women.

What is known already

The prevalence of ANA is well-known to be higher in RPL patients. Our previous study found no difference in the live birth rates of ANA-positive and -negative patients who had no aPLs. Higher miscarriage rates were also reported in ANA-positive patients compared to ANA-negative patients with RPL. The RPL guidelines of the ESHRE state that “ANA testing can be considered for explanatory purposes.” However, there have been a limited number of studies on this issue and sample sizes have been small, and the impact of ANA on the pregnancy prognosis is unclear.

Study design, size, duration

An observational cohort study was conducted at Nagoya City University Hospital between 2006 and 2019. The study included 1,108 patients with a history of 2 or more pregnancy losses.

Participants/materials, setting, methods

4D-Ultrasound, hysterosalpingography, chromosome analysis for both partners, aPLs and blood tests for ANA and diabetes mellitus were performed before a subsequent pregnancy. ANAs were measured by indirect immunofluorescence. The cutoff dilution used was 1:40. In addition, patients were classified according to the ANA pattern on immunofluorescence staining. Live birth rates were compared between ANA-positive and ANA-negative patients after excluding patients with antiphospholipid syndrome, an abnormal chromosome in either partner and a uterine anomaly.

Main results and the role of chance

The 994 patients were analyzed after excluding 40 with a uterine anomaly, 43 with a chromosome abnormality in either partner and 32 with APS. The rate of ANA-positive patients was 39.2 % (390/994) when the 1: 40 dilution result was positive. With a 1:160 dilution, the rate of ANA-positive patients was 3.62 % (36/994). The live birth rate was calculated for 798 patients, excluding 196 patients with unexplained RPL who had been treated with any medication.

With the use of the 1

40 dilution, the subsequent live birth rates were 71.34 % (219/307) for the ANA-positive group and 70.67 % (347/491) for the ANA-negative group (OR, 95%CI; 0.968, 0.707-1.326). After excluding miscarriages with embryonic aneuploidy, chemical pregnancies and ectopic pregnancies, live birth rates were 92.41 % (219/237) for the ANA-positive group and 92.04 % (347/377) for the ANA-negative group (0.951, 0.517-1.747).

Using the 1:160 dilution, the subsequent live birth rates were 84.62 % (22/26) for the ANA-positive group, and 70.47 % (544/772) for the ANA-negative group (0.434, 0.148-1.273).

Subgroup analyses were performed for each pattern on immunofluorescence staining, but there was no significant difference in the live birth rate between the two groups.

Limitations, reasons for caution

The effectiveness of immunotherapies could not be evaluated. However, the results of this study suggest that it is not necessary.

Wider implications of the findings

The measurement of ANA might not be necessary for the screening of patients with RPL who have no features of collagen disease.

Trial registration number

not applicable

Three-dimensional conformal radiation therapy for canine aortic body tumour: 6 cases (2014-2019)

OBJECTIVE

To determine the feasibility of three-dimensional conformal radiation therapy for canine aortic body tumours.

MATERIALS AND METHODS

Medical records of dogs that had undergone three-dimensional conformal radiation therapy with presumptive diagnosis of aortic body tumour were reviewed for clinical characteristics, treatment modality and outcomes.

RESULTS

Eight dogs were diagnosed with aortic body tumour and were treated with three-dimensional conformal radiation therapy. One dog had proliferation of a mass in the right atrium during treatment and died of respiratory distress. Another dog did not undergo follow-up CT to evaluate the treatment response due to the increased blood urea nitrogen values. The remaining 6 dogs were included in the case series. Radiotherapy was performed using a median dose per fraction of 7 Gy (3.3-7.14 Gy), a median of seven divided doses (7-15) and a total median dose of 49 Gy (45-50 Gy). The median number of CT scans during the follow-up period was 5 (range: 3-8 times). CT revealed acute side effects in four dogs-grade 1 effects related to the lung (n = 4) and skin (n = 2). Self-limiting or asymptomatic late side effects (grade 1 lung-related effect) were observed in three dogs. After therapy, one dog demonstrated a complete response, another demonstrated a partial response and the disease remained stable in four animals. The median follow-up period was 514.5 (235-1219) days. After three-dimensional conformal radiation therapy, the aortic body tumour reduced gradually over time without regrowth in all these 6 dogs.

CLINICAL SIGNIFICANCE

In this small case series, aortic body tumours responded to three-dimensional conformal radiation therapy. Transient and self-limiting side effects of the treatments were common. Further controlled studies are required to prove the effectiveness and the safety of this intervention.

A novel causative gene variant, TNFRSF13B p.Gly76Ser, in patients with pulmonary arterial hypertension

Background

Pulmonary artery hypertension (PAH) is a poor prognostic disease. Some causative genes were reported as the PAH-associated genes. However, the pathogenetic variants in PAH-associated genes have not been identified in majority of patients with idiopathic PAH.

Purpose

Our aim was to investigate the new causative gene variants associated with PAH.

Methods

We performed whole-exome sequencing in 272 patients with idiopathic/heritable PAH. Structural analysis simulation was performed to define how the candidate gene variant affected the structure of protein.

Results

We identified the heterozygous substitution change of c.226G&gt;A (p.Gly76Ser, rs146436713) in tumor necrotic factor receptor superfamily 13B gene (TNFRSF13B) (NM_012452.2) in 6 (2.2%) patients with idiopathic/heritable PAH, although the allele frequency of this rare variant is 0% in Integrative Japanese Genome Variation Database (control population database). Two of the six cases were blood relatives, although they did not have the known causative gene variants of PAH. One of these two relatives died of right heart failure despite the combination medical therapy, and her pathological anatomy demonstrated intimal thickening and medial hypertrophy in the pulmonary arteries, formation of plexiform lesions (Heath-Edwards classification grade V). Time-lapse images from structural analysis simulation showed the instability of N-terminal in the protein, which regulates the vascular inflammation, synthesized from TNFRSF13B p.Gly76Ser variant (Figure), suggesting that p.Gly76Ser variant may be involved in the development of PAH via aberrant inflammation in pulmonary vessels.

Conclusions

TNFRSF13B p.Gly76Ser variant is a candidate of causative gene variant for PAH.

Structural analysis of proteins

Funding Acknowledgement

Type of funding source: None

The effect of body mass index on clinical outcomes in patients with newly diagnosed atrial fibrillation in the GARFIELD-AF registry

Introduction

Higher body mass index (BMI) is associated with a higher risk of atrial fibrillation (AF). However, previous evidence has suggested an inverse association between BMI and risk of AF outcomes.

Purpose

To explore the association between BMI and outcomes in those with newly diagnosed AF in the GARFIELD-AF registry.

Methods

GARFIELD-AF is an international registry of consecutively recruited patients aged ≥18 years with newly diagnosed AF and ≥1 stroke risk factor. Data were collected prospectively on 52,080 patients. Participants with missing or extreme BMI values and those without two-year follow-up were excluded. Cox proportional hazard models were used to estimate the effect of BMI on the risk of outcomes. Models were adjusted for age, sex, ethnicity, smoking, alcohol, and ≥moderate chronic kidney disease. Where appropriate participants were divided into groups based on BMI. Restricted cubic splines were used to assess non-linear relationships.

Results

BMI and outcome data were available for 40,495 patients. Those with higher BMI were generally younger, and more likely to have pre-existing hypertension, diabetes, or vascular disease (Table). Underweight patients received anticoagulation less often than those in other groups (60.3% vs 67.9%, respectively). During follow-up, 2,801 participants (6.9%) died and 603 (1.5%) had new/worsening heart failure. Following adjustment for potential confounders, a U-shaped relationship was seen between BMI and all-cause mortality and new/worsening heart failure (Figure). For all-cause mortality, the lowest risk was at 30kg/m2. Below this level, there was an 8% higher risk of mortality (95% confidence interval (CI) 6 to 9%) per 1kg/m2 lower BMI. Above 30kg/m2, there was a 5% higher risk of mortality per 1kg/m2 higher BMI (95% CI 4 to 7%). For new/worsening heart failure, the lowest risk was at 25kg/m2. Above this level, 1kg/m2 higher BMI was associated with an 5% higher risk (95% CI 13 to 6%).

Conclusions

BMI was an important risk factor for both all-cause mortality and new/worsening heart failure in AF. Those at both extremes of BMI are at higher risk.

BMI and selected outcomes

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): The GARFIELD-AF registry is funded by an unrestricted research grant from Bayer AG.

Permanent discontinuation of different anticoagulants in patients with atrial fibrillation and the impact on clinical outcome: data from the GARFIELD-AF registry

Background

Non-Vitamin K Antagonists (NOAC) are replacing vitamin K Antagonists (VKA) as first line oral anticoagulant therapy (OAC) in patients with non-valvular atrial fibrillation (NVAF). Discontinuation of OAC might put patients at increased risk. It was anticipated that patients who were on NOAC would discontinue OAC less.

Purpose

We compare the rates and impact on outcome of the discontinuation of NOAC and VKA using data from the GARFIELD-AF registry.

Methods

Patients included in GARFIELD-AF, had a new diagnosis of NVAF and at least 1 stroke risk factor. In this analysis 26,299 patients (VKA: 13,012; NOAC: 13,287) that received OAC were included. Permanent discontinuation was defined as stopping OAC for at least 7 consecutive days (whether or not restarted during follow-up). Marginal structural Cox proportional hazards models estimated the effect of discontinuation on death, cardiovascular (CV) death, non-haemorrhagic stroke + systemic embolism (NHS+SE), myocardial infarction (MI), or combined endpoints. Adjustments were made for both baseline factors and time dependent variables.

Results

Of all patients, 15.6% discontinued OAC (VKA: 15.4%; NOAC: 15.8%) over a median follow-up of 181 days (IQR: 359). Most discontinued early (67.0% of patients on VKA and 47.1% of patients on NOAC ≤4 months). Significantly higher discontinuation risk was seen with worsening kidney function, coronary artery disease, history of bleeding (baseline factors), as well as with all types of bleeding (time dependent factors). Lower discontinuation rates were seen with history of stroke/TIA, hypertension, increasing age, permanent AF (all p&lt;0.01).

Mean CHA2DS2-VASc score was 3 in all groups. Patients in both treatment arms who discontinued were at increased risk for death, NHS+SE, MI as well as combined endpoints of death/NHS+SE/MI, death/NHS+SE and a trend towards higher CV death (Figure 1). All interaction tests for the interaction of treatment and discontinuation had a p value &gt;0.4. The association between discontinuation and outcomes did not change when a 30 day discontinuation window was used.

Conclusion

The rate of discontinuation in this study was 15.8% and comparable for VKA and NOAC over a 2-year follow-up. Discontinuation rates were the highest soon after the initiation of treatment. When VKA or NOAC was stopped for ≥7 consecutive days, the risk of NHS+SE, death, MI or any combined endpoints were significantly worse in both treatment arms. These data suggest that discontinuation of anticoagulant treatment with VKA or NOAC should be discouraged.

HR of patients who discontinued OAC

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): The GARFIELD-AF registry is funded by an unrestricted research grant from Bayer AG.

Clinical outcomes of patients with newly diagnosed atrial fibrillation who refused anticoagulation: findings from the global GARFIELD-AF registry

Introduction

Atrial fibrillation (AF) remains a common cause of stroke and anticoagulation (AC) treatment reduces the risk of stroke. Reasons for patients with AF not receiving anticoagulation are generally attributed to the clinician decision, however in reality a proportion of patients refuse anticoagulation. The aim of our study was to investigate the clinical outcomes of patients with AF who refused anticoagulation.

Methods

The Global Anticoagulant Registry in the FIELD (GARFIELD-AF) was an international prospective observational study of patients ≥18 years with newly diagnosed AF and ≥1 investigator determined risk factor for stroke. We analysed two-year outcomes (unadjusted) of non-haemorrhagic stroke/systemic embolism (stroke/SE), major bleeding and all-cause mortality in patients at high risk of stroke (men with CHA2DS2VASc≥2 and women with CHA2DS2VASc≥3) who did not received anticoagulation due to patient refusal, patients at high risk of stroke who received anticoagulation, and patients who were not on anticoagulation due to reasons other than patient refusal.

Results

Out of 43,154 patients, 13,283 (30.8%) are at the higher risk of stroke and did not received anticoagulation at baseline. The reason for not receiving anticoagulation was unavailable for 38.7% (5146/13283); of the patients with a known reason for not receiving anticoagulation, 12.5% (1014/8137) refused anticoagulation. Overall the study participants had a mean (SD) age of 72.2 (9.9) years and 50% were female. The median (Q1; Q3) CHA2DS2VASc score was 3.0 (3.0; 5.0) in patients who refused anticoagulation and 4.0 (3.0; 4.0) in patients who received anticoagulation. The median (Q1; Q3) HAS-BLED score was 1.0 (1.0; 2.0) in both groups. Of the patients who received anticoagulants, 59.7% received VKA and 40.3% received non-VKA oral anticoagulants. 79.4% of patients who refused anticoagulation were on antiplatelets. At two-year follow up the rate of events per 100 person-years (AC refused vs AC received) were: stroke/SE 1.42 vs 0.95 (p=0.04), major bleeding 0.62 vs 1.20 (p=0.02), and all-cause mortality 2.28 vs 3.90 (p=0.0004) (Figure). The event rates in patients who were not on anticoagulation for reasons other than patient refusal were stroke/SE 1.56, major bleeding 0.91, and all-cause mortality 5.49.

Conclusion

In this global real-world prospective study of patients with newly diagnosed AF, patients who refused anticoagulation had a higher rate of stroke/SE but lower rates of all-cause mortality and major bleeding than patients who received anticoagulation. While patient refusal of anticoagulation is an acceptable outcome of shared decision-making, clinically it is a missed opportunity to prevent AF related stroke. Patients' beliefs about AF related stroke and anticoagulation need to be explored. The difference in all-cause mortality warrants further investigation; further analysis will include adjusted results.

Event rates at two years of follow-up

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): The GARFIELD-AF registry is funded by an unrestricted research grant from Bayer AG.

Guideline-directed medical therapies for comorbidities among patients with atrial fibrillation: results from GARFIELD-AF

Introduction

The GARFIELD-AF registry is a prospective, multicentre, observational study of adults with recently diagnosed non-valvular atrial fibrillation (AF) and at least one risk factor for stroke. In GARFIELD-AF the absolute risk reduction of mortality associated with anticoagulation is far greater than the apparent absolute risk reduction in (ischemic) stroke. One potential explanation is improved treatment, with the use of comprehensive guideline-directed medical therapies (GDMT), in patients with AF receiving oral anticoagulant (OAC) therapy. The objectives were to identify the potential relationships between anticoagulation status, GDMT use and clinical outcomes.

Methods

Use of GDMT was determined on the basis of published European Society for Cardiology guidelines operative between 2010 and 2016. We explored the use of GDMT in patients enrolled in GARFIELD-AF (March 2010-Aug 2016) with CHA2DS2-VASc ≥2 and with one or more of five comorbidities–coronary artery disease, diabetes mellitus, heart failure, hypertension and peripheral vascular disease. Association between GDMT use and clinical outcomes events was evaluated with Cox-proportional hazards models. The models included stratification by all possible combinations of the five comorbidities used to define GDMT eligibility.

Results

The study population comprised of 39,946 patients who had one or more comorbidities (3238 [8.1%] received none of the GDMT, 17,398 [43.6%] received some, and 19,310 [48.3%] received all of the GDMT for which they were eligible). Patients on OAC tended to receive all the GDMTs more frequently compared to patients on no OAC (50.2% vs 44.8%, respectively).

Comprehensive GDMT was associated with a lower risk of all-cause mortality (HR: 0.89 [0.80–0.99]) and non-cardiovascular mortality (0.80 [0.68–0.95]) compared to inadequate or no GDMT but was not associated with a lower risk of stroke (HR: 1.04 (0.88–1.24)] (Figure). The effect of OAC was beneficial for mortality and stroke risk whether receiving comprehensive GDMT or not.

Conclusion

OAC therapy is associated with a lower risk of all-cause mortality, non-cardiovascular mortality and stroke/SE in comparison with no OAC, irrespective of GDMT use in patients with CHA2DS2-VASc ≥2. Although the use of GDMT is associated with a significant reduction in mortality, there is little evidence that this explains the decrease in mortality with the use of OAC.

GDMT use at two years of follow-up

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): The GARFIELD-AF registry is funded by an unrestricted research grant from Bayer AG.

P6009Poor outcomes in pulmonary arterial hypertension as a member of RNF213-associated vascular diseases

Background

A variant of c.14429G>A (p.Arg4810Lys, rs112735431) in the ring finger protein 213 gene (RNF213; NM_001256071.2) has been recently identified as a risk allele for pulmonary arterial hypertension (PAH), suggesting that PAH can be added as a new member of RNF213-associated vascular diseases including Moyamoya disease and peripheral pulmonary stenosis.

Purpose

Our aim was to identify the clinical features and outcomes of PAH patients with RNF213 p.Arg4810Lys variant.

Methods

Whole-exome sequencing was performed in 139 idiopathic (or possibly heritable) PAH patients. Hemodynamics and prognosis were evaluated in the patients with RNF213 p.Arg4810Lys variant and the patients with bone morphogenic protein receptor type 2 (BMPR2) mutations.

Results

The RNF213 p.Arg4810Lys variant was identified in a heterozygous state in 11 patients (7.9%). Time-course changes in hemodynamics after combination therapy in the patients with the RNF213 p.Arg4810Lys variant were significantly poorer compared with those in BMPR2 mutation carriers (n=36) (comparison of changes in mean pulmonary arterial pressure, P=0.007). The event-free rate of death or lung transplantation was significantly poorer in RNF213 p.Arg4810Lys variant carriers than in BMPR2 mutation carriers (5-year event-free rate since the introduction of prostaglandin I2 infusion, 0% vs. 93%, P<0.001) (Figure).

Time to death or lung transplantation

Conclusions

PAH patients with the RNF213 p.Arg4810Lys variant were associated with a poor reactivity to vasodilator drugs and poor clinical outcomes even in the recent era. Earlier consideration of lung transplantation might be required for RNF213 p.Arg4810Lys variant carriers developing PAH. Documentation of the RNF213 p.Arg4810Lys variant, as well as already known pathogenic genes, can provide clinically relevant information for therapeutic strategies, leading to a personalized approach for the treatment of PAH.

Influence of loading rate and limb position on patellar tendon mechanical properties in vivo

BACKGROUND

The aims of this study were to clarify the changes of patellar tendon length during isometric knee joint extension and the double leg squat position using ultrasonography.

METHODS

The left legs of 17 healthy adults were investigated. Isometric knee extension motion was performed at three positions of knee flexion 30° (knee 30°), knee flexion 60° (knee 60°), knee flexion 90° (knee 90°), and at each limb position, 0% (0% peak torque (PT)), 40% (40% PT), 50% (50% PT), and 60% (60% PT) of the maximum knee joint extension torque were executed at random. Both double leg squat motions were randomly performed in three positions: hip flexion 30°, knee flexion 30°, ankle dorsiflexion 10° (squat 30°); hip joint flexion 60°, knee joint flexion 60°, ankle dorsiflexion 20° (squat 60°); and hip joint flexion 90°, knee joint flexion 90°, ankle dorsiflexion 30° (squat 90°). Ultrasonography was used to measure patellar tendon length.

FINDINGS

There were no significant changes in patellar tendon length and strain between knee flexion angles of 30°, 60°, and 90° in isometric knee joint extension and the double leg squat limb position.

INTERPRETATION

The loading rate and limb position do not appear to affect the length and strain of the patellar tendon.

Antiplatelet therapy after coronary intervention in Asia and Japan

Currently available clinical database was mostly developed in North America and Europe (Western Countries). Clinical database of Asian patients are still not large enough to develop Asian region specific clinical guidelines, although the population of patients in the majority of Asia countries are increasing rapidly. Marked ethnic and life-style heterogeneity within Asian region also makes it difficult to develop Asian region specific Evidence-based clinical practice guidelines. In general, there are certain differences in the background epidemiology of the athero-sclerotic and thrombotic diseases in Asia countries and Western ones such as Asian patients are more prone to cerebrovascular disease (CVD) than coronary artery disease (CAD). Accordingly, there also are marked differences in the use of antiplatelet agents in Asian patients underwent coronary intervention (such as frequent use of cilostazol) as compared to those living in the Western countries. Currently available database also suggests the difference in side effects of anti -platelet agents in Asian patients as compared to Western ones such as relatively high incidence of hepatic dysfunction with the use of thienopiridine. In the future, it would be important to clarify the detailed difference of Asian patients and Western ones in regards to the effects and side effects of antiplatelet therapy by the multi-national prospective observation registry and clinical trials including equal number of Asian and Western patients. It would also be important for Asian physician to develop scientifically valid methods to import the results of “Global Evidence” with appropriate modification for the clinical practice in patients living in the specific region of Asia.

Role of Multichance Fission in the Description of Fission-Fragment Mass Distributions at High Energies

Fission-fragment mass distributions were measured for ^{237-240}U, ^{239-242}Np, and ^{241-244}Pu populated in the excitation-energy range from 10 to 60 MeV by multinucleon transfer channels in the reaction ^{18}O+^{238}U at the Japan Atomic Energy Agency tandem facility. Among them, the data for ^{240}U and ^{240,241,242}Np were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multichance fission.

Ultra-strong and damage tolerant metallic bulk materials: A lesson from nanostructured pearlitic steel wires

Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today’s strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material’s strength.