Real-time observation of polarization dependence of soft x-ray absorption spectrum during chemical reaction under near-ambient pressure conditions

The real-time observation of the polarization dependence of soft x-ray absorption spectra during chemical reactions is realized by combining the fluorescence-yield wavelength-dispersive x-ray absorption spectroscopy technique with a 10 Hz switching between horizontal and vertical polarizations. The soft x-ray absorption spectra for both the horizontal and vertical polarizations are recorded every 100 ms with a time difference of 50 ms, which enables the real-time observation of changes in the anisotropic structure around the surface. The technique is applied to the oxidation reaction of a cobalt thin film under an air pressure of up to 25 Pa, and it is suggested that an anisotropic structure appears during the growth of the cobalt oxide species. By using the developed technique, it is expected that the changes in the anisotropic structures, such as molecular orientations, are observed during chemical reactions under near-ambient pressure conditions, which gives a deeper insight into the understanding of the reaction mechanism.

Utility of in vivo zebrafish cardiac assay to predict the functional impact of KCNQ1 variants

Background

Genetic testing for inherited arrhythmias and discriminating pathogenic from benign variants are integral for the gene-based medicine. However, the high throughput in vivo functional analysis for the rare variants of the KCNQ1 potassium channel is scarce.

Purpose

We tested the utility of the in vivo zebrafish cardiac assay for determining the pathogenicity of the KCNQ1 variants identified in patients with long QT syndrome (LQTS) and atrial fibrillation (AF).

Methods

We generated a knock-out zebrafish with CRISPR-mediated insertions or deletions of the KCNQ1 homolog in zebrafish (kcnq1+/+). To test the utility of the cardiac assay, we used five KCNQ1 variants identified in patients with LQTS or familial AF. Human wild-type or mutant KCNQ1 cRNA (Q1) was co-injected with human KCNE1 cRNA (E1) into the F3 generation embryos with homozygous deletions. We dissected the hearts from the thorax at 72 hour-post-fertilization and measured transmembrane potential in zebrafish heart using the disrupted patch technique. Action potential duration was calculated as the time interval between the peak maximum upstroke velocity and 90% of repolarization (APD90). We compared the APD90s with patients' clinical phenotype and IKs density measured by patch-clamp technique in heterologous system.

Results

The mean APD90 of embryos with kcnq1del/del was 279±48 ms, which was restored by injecting Q1 WT and E1 (159±29 ms) to that with kcnq1+/+ (167±28 ms). We tested if the mean APD90 of embryos with kcnq1del/del was restored (shortened) by injecting the KCNQ1 variants. First we tested the dominant negative variant p.S277L and the trafficking deficient variant p.T587M. Patients with these variants showed significant prolonged QT intervals, and patch clamp study showed both variants caused the non-functional channels. Zebrafish cardiac assay showed the mean APD90 of embryos with kcnq1del/del+ Q1 S277L+E1 or Q1 T587M+E1 was significantly longer than that with kcnq1del/del+Q1 WT+E1 (Table). Next we tested in-frame variant c.1472_1473 ins GGACCT, which was identified from a patient with AF and normal QT interval. Patch clamp study showed the current density of the mutant KCNQ1 channel with KCNE1 was comparable to that of wild-type KCNQ1 channel with KCNE1. Zebrafish assay showed the mean APD90 of embryos with kcnq1del/del shortened by injecting Q1 insACCTGG +E1 (Table). Finally we tested a missense variant p.R451Q, which was identified from a patient with LQTS. Patch clamp study showed the currents in the cells transfected with R451Q+KCNE1 were similar to those with WT+KCNE1. Zebrafish assay showed the mean APD90 of embryos with kcnq1del/del+Q1 R451Q+E1 was longer than that with kcnq1del/del+Q1 WT+E1 (Table).

Conclusions

Functional analysis of in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants in patients with LQTS.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The Grant-in-Aid for Scientific Research (C)

Progression of liver fibrosis in pulmonary arterial hypertension

Background

Pulmonary arterial hypertension (PAH) causes congestive liver due to right heart failure. There are few cases of PAH that lead to liver cirrhosis, and little attention is paid to liver function in PAH patients. However, it is certain that long-term congestion due to right heart failure in PAH causes a gradual exacerbation of liver dysfunction and affects metabolic function.

Purpose

The purpose of this study is to investigate liver fibrosis associated with the severity and prognosis of PAH.

Methods

This retrospective observational study was included 57 PAH patients and 22 control subjects. PAH patients were assigned to three risk variables according to the simplified risk stratification proposed at the 6thWSPH 2018 after measuring hemodynamic parameters using right heart catheterization, WHO functional class, 6- minutes walking distance (6MWD), and BNP plasma levels. The Fibrosis-4 (FIB4)-index, a liver fibrosis marker, was calculated using the formula: FIB-4 = Age (years) × AST (U/L) / [PLT (109/L) × ALT1/2 (U/L)], and assessed for association with severity of PAH. PAH patients were followed up for 12 years to assess the occurrence of major adverse event, such as death or lung transplantation.

Next, adult 8-week-old C57BL/6 mice were exposed to chronic hypoxia (10% O2) or normoxia for 6 weeks. Then, mice were anesthetized and performed right heart catheterization. Liver tissue was collected for histological assessment by Hematoxylin and eosin and Azan staining, and evaluated RNA expression involved in liver fibrosis by real-time PCR.

Results

The levels of FIB4-index in intermediate and high risk groups of PAH patients had significantly increased compared to those in control group. In PAH patients, FIB4-index was not obviously correlated with hemodynamic parameters, BNP, or 6MWD. Major adverse events occurred in 18 PAH patients (32%): death in 18 (100%) and lung transplant in none (0%). Kaplan-Meier curves for PAH patients with and without major adverse events were constructed based on a cut-off frequency of 2.001 for FIB4-index. During the 12-years follow-up period, major-event-free survival was significantly better in PAH patients with FIB4-index <2.001 than in patients with FIB4-index >2.001 (hazard ratio, 3.3; P=0.038).

In a PAH model mice, hemodynamic parameters showed that chronic hypoxia significantly increased the right ventricular systolic pressure. In histological analysis, there was no significantly difference in liver fibrosis in hypoxia or normoxia group. However, the RNA expression such as αSMA and TGFβ1 associated with liver fibrosis in PAH model mice was increased compared to control mice.

Conclusion

This study showed that the liver fibrosis gradually progressed subsurfacely with severity of PAH. Even the slight liver dysfunction may affect metabolism and cause exacerbation of PAH, so it might be necessary to pay attention to liver fibrosis as one of the risk factors of PAH.

Funding Acknowledgement

Type of funding sources: None.

Different contribution of sympathetic nerve activity to arterial velocity pulse index in hypertensive patients with and without diastolic dysfunction

Introduction

Left ventricular diastolic dysfunction (LVDD) is the main cause of heart failure with preserved ejection fraction (HFpEF). LVDD is related not only to arterial stiffness but also sympathetic nerve activity (SNA). Recent study demonstrated that increased muscle sympathetic nerve activity (MSNA) may be one of contributing factor for arterial stiffness. In clinical practice, Cardio-ankle vascular index (CAVI) provides a reproducible index of arterial stiffness, independent of blood pressure (BP). Recently, Arterial Velocity pulse Index (AVI), which is an index of arterial reflected waves, have been proposed as new index of arterial stiffness. We reported that AVI was associated with MSNA in hypertensive (HT) patients. However, it is still uncertain the effect of LVDD on the association between AVI and SNA in HT patients. Thus, we tested the hypothesis that AVI would be increased and related to MSNA in HT patients with LVDD.

Methods

Patients with essential HT subjects were included in this study. HT was diagnosed as systolic blood pressure (SBP) ≥140mmHg or diastolic blood pressure (DBP) ≥90mmHg. Patients with secondary HT was excluded. AVI was measured from left upper arm by NAS-1000 (Nihon Koden, Japan). CAVI was measured by VaSera VS-1500A (Fukuda Denshi, Japan). Transthoracic echocardiography was performed by trained sonographers. SNA was evaluated by direct recording of MSNA from peroneal nerves.

Results

25 HT patients were included (age 63±14 years, Male/Female 9/16). They were divided into two groups according to E/e' (no LVDD group, E/e' ≤9, N=12; LVDD group, E/e' >9, N=13). There were no significant differences between no LVDD and LVDD groups in age (63±9 vs 69±9 years p=0.205), body mass index (23±3 vs 24±4 p=0.355), BP (SBP 139±16 vs 144±20mmHg p=0.524, DBP 87±15 vs 78±14mmHg p=0.167). LV Ejection Fraction (EF) and Stroke Volume (SV) did not differ between two groups (EF 66±7 vs 69±6% p=0.471, SV 58±7 vs 62±14ml p=0.599). MSNA had tendency to increase in LVDD group compared to no LVDD group (MSNA 53±10 vs 44±12 bursts/100 heartbeats, p=0.052). Contrary to our hypothesis, AVI and CAVI did not differ between two groups (AVI 27±7 vs 29±7 p=0.398, CAVI 8.7±1.4 vs 8.6±1.4 p=0.894). However, a significant correlation was seen between AVI and MSNA in no LVDD group (r=0.57, p<0.05), but no correlation in LVDD group. There is no correlation between CAVI and MSNA in no LVDD and LVDD group. Significant relationship was observed between AVI and CAVI in LVDD group (r=0.61, p<0.05), but no relationship in no LVDD group.

Conclusion

AVI was significantly associated with MSNA in HT patients without LVDD, but not with LVDD. CAVI was related to AVI in HT patients with LVDD, but not without LVDD. MSNA was slightly increased in HT patients with LVDD compared to without LVDD. These results indicate that augmented SNA could contribute to the increase in arterial stiffness in HT patients without LVDD, however, this contribution might be attenuated in HT patients with LVDD.

Funding Acknowledgement

Type of funding sources: None.

Novel variant of the glycerol-3-phosphate dehydrogenase-1 Like (GPD1-L) gene in Japanese Brugada syndrome patients

Background

The incidence of Brugada syndrome (BrS) varies among racial groups. Several studies reported Glycerol-3-Phosphate Dehydrogenase 1-Like (GPD1-L) gene is associated with BrS. However, most of these studies were reported from Western countries, so the evidence about GPD1-L mutation is limited especially among Asian BrS patients. This study aimed to search for rare variants in GPD1-L among Japanese BrS patients and to investigate the pathogenicity.

Method

We performed whole-exome sequencing for patients with Brugada type 1 ECG pattern from Japanese multicenter BrS cohort consisting of SCN5A-negative BrS probands (n=288) and controls (n=372). We conducted patch-clamp study in human embryonic kidney (HEK) 293 cells cotransfected with the wild-type sodium channel (SCN5A) and wild-type or mutant GPD1-L expression plasmid.

Results

We identified a rare variant in GPD1-L, p.D262N (c.784g>a) in 2 of 288 BrS probands, which was not identified in 372 controls. The minor allele frequency of the variant is 0.0014% in the Genome Aggregation Database. One proband was a 49-year-old man and the other was 34-year-old man who both developed a ventricular fibrillation. ECGs of both probands showed Brugada Type 1 pattern after administration of the pilsicainide. In functional study, coexpression of D262N GPD1-L with SCN5A in HEK293 cells significantly reduced inward sodium currents compared with wild-type GPD1-L. Additionally, inward sodium currents with D262N were similar to those with A280V GPD1-L, which was associated with BrS in previous reports (Figure). Also, several pathogenicity prediction programs, such as SIFT (score: 0.031) and PolyPhen2 (score: 0.937) predicted deleterious effects of GPD1-L D262N.

Conclusion

We identified a rare variant in GPD1-L at the rate of 0.7% in Japanese BrS patients without SCN5A mutations. GPD1-L, p.D262N reduces inward sodium currents and may be a novel susceptible variant for BrS in the Japanese population.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Current–voltage curve

Age differences in the association between arterial velocity pulse index and muscle sympathetic nerve activity in hypertensive patients

Background

Increased arterial stiffness characterize by aging. It is reported that age-related increases in muscle sympathetic nerve activity (MSNA) may be one of contributing factor for arterial stiffness. Arterial reflected wave was composed of SNA and aging. Increased arterial reflected wave partly plays an important role in blood pressure. Recently, we reported that arterial velocity pulse index (AVI), a novel index of arterial reflected waves, was associated with MSNA in hypertensive patients. It is still uncertain the effect of age on the association between AVI and SNA in hypertensive patients.

Method

Patients with essential HT and matched non-hypertensive control subjects were included in this study. HT was diagnosed as systolic blood pressure (SBP) ≥140 mmHg or diastolic blood pressure (DBP) ≥90 mmHg. AVI was measured from left upper arm by NAS-1000. SNA was evaluated by direct recording of muscle sympathetic nerve activity (MSNA) from peroneal nerves.

Results

45 HT patients and 46 control subjects were included. Age, SBP and DBP were significantly increased in HT group compared to control (Age 63±14 vs 42±16 years, p<0.001; SBP 144±16 vs 115±9 mmHg, p<0.001; DBP 80±14 vs 67±9 mmHg, p<0.001). MSNA and AVI were significantly increased in HT group compared to control (MSNA 34±10 vs 25±8 bursts/min, p<0.05; AVI 28±9 vs 17±5, p<0.05). AVI was significantly correlated with MSNA, age, and SBP in HT group. HT group was divided into two groups according to their age (group 1, age ≤63 N=21, group 2, age ≥64 N=26). AVI in group 1 showed correlation with MSNA (r=0.59, p<0.05), but no correlation was seen in group 2. However excluded SBP>160 mmHg subjects in group 2, significant correlation was clarified between AVI and MSNA (r=0.62, p<0.05).

Conclusion

The relationship between AVI and MSNA in HT patients is preserved regardless of aging, however, high blood pressure over 160mmHg might obscure its correlation. These results indicate that AVI is useful to estimate sympathetic nerve activity in high aging HT patient treated <160 blood pressure.

Funding Acknowledgement

Type of funding sources: None.

Early detection of exacerbation of the severe acute respiratory syndrome coronavirus 2 infection using Fitbit (DEXTERITY pilot study)

 

Some patients with coronavirus disease 2019 (COVID-19) experienced sudden death because of sudden symptom deterioration. Thus, an alarm system that could detect early signs of COVID-19 exacerbation beforehand, to prevent serious illness or death of patients while receiving outpatient treatment at home or in hotels is necessary. Here, we tested whether estimated oxygen variations (EOV), a relative physiological scale that represents users' blood oxygen saturation level during sleep measured by Fitbit, predicted COVID-19 symptom exacerbation. Study period was from August to November 2020. We enrolled 23 COVID-19 patients diagnosed by SARS-CoV-2 polymerase chain reaction-positive (mean age ± standard deviation, 50.9±20 years; 70% female), let each patient wore the Fitbit for 30 days; COVID-19 symptoms were exacerbated in 6 (26%). High EOV signal (a patient's oxygen level exhibits significant dip and recovery within the index period) had 80% sensitivity before symptom exacerbations, whereas resting heart rate signal only had 50% sensitivity. Coincidental obstructive sleep apnea syndrome confirmed by polysomnography was detected in a patient by consistently high EOV signals. This pilot study successfully detected early COVID-19 symptoms exacerbation by measuring EOV and may help to identify early signs of COVID-19 exacerbation.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The investigational device used in this study, Fitbit Charge 3, was provided by Fitbit Japan. Summary of high EOV signals and eventsThe clinical course of COVID-19

First X-ray Spectroscopic Observations of Atmospheric Titanium Species: Size Dependence and the Emission Source

Titanium dioxide (TiO2) in mineral dust is considered as one of the driving forces of photocatalytic reaction at the aerosol surface in the atmosphere. As a precursor of mineral dust, soil contains ilmenite (FeTiO3) and titanite (CaSiTiO5), which have lower photochemical reactivities than TiO2. However, Ti species other than TiO2 in aerosol particles are not well recognized due to the lack of observation in ambient samples. In this study, Ti species in size-fractionated aerosol samples collected in the Noto Peninsula, Japan, were determined by macroscopic and semi-microscopic X-ray absorption fine structure spectroscopy. Regardless of aerosol particle size, Ti species were primarily composed of rutile, anatase, ilmenite, and titanite. Semi-microscopic Ti speciation showed that Ti-poor spots associated with mineral dust were composed of a mixture of rutile, anatase, ilmenite, and titanite, and Ti-rich spots were primarily composed of TiO2 (rutile or anatase) derived from authigenic minerals or anthropogenic materials. Thus, the Ti species in aerosol particles, especially mineral dust, were not composed solely of TiO2 polymorphs. Therefore, the photochemical reactivities of Ti in aerosol particles may be overestimated when laboratory experiments or model studies employ TiO2 as the representative Ti species.

Broadband high-energy resolution hard x-ray spectroscopy using transition edge sensors at SPring-8

We have succeeded in operating a transition-edge sensor (TES) spectrometer and evaluating its performance at the SPring-8 synchrotron x-ray light source. The TES spectrometer consists of a 240 pixel National Institute of Standards and Technology (NIST) TES system, and 220 pixels are operated simultaneously with an energy resolution of 4 eV at 6 keV at a rate of ∼1 c/s pixel^-1. The tolerance for high count rates is evaluated in terms of energy resolution and live time fraction, leading to an empirical compromise of ∼2 × 10³ c/s (all pixels) with an energy resolution of 5 eV at 6 keV. By utilizing the TES's wideband spectroscopic capability, simultaneous multi-element analysis is demonstrated for a standard sample. We conducted x-ray absorption near-edge structure (XANES) analysis in fluorescence mode using the TES spectrometer. The excellent energy resolution of the TES enabled us to detect weak fluorescence lines from dilute samples and trace elements that have previously been difficult to resolve due to the nearly overlapping emission lines of other dominant elements. The neighboring lines of As Kα and Pb Lα2 of the standard sample were clearly resolved, and the XANES of Pb Lα2 was obtained. Moreover, the x-ray spectrum from the small amount of Fe in aerosols was distinguished from the spectrum of a blank target, which helps us to understand the targets and the environment. These results are the first important step for the application of high resolution TES-based spectroscopy at hard x-ray synchrotron facilities.

Recurrence of atrial fibrillation after catheter ablation is associated with major adverse cardiac and cerebrovascular events: insights from AF frontier ablation registry

Background

Recent observational studies have suggested that catheter ablation for atrial fibrillation (AF) is significantly associated with reduced risk for stroke, cardiovascular events and all-cause death. However, little is known whether late recurrence of AF after catheter ablation is associated with worse clinical outcomes.

Purpose

We aimed to clarify whether late recurrence of AF after catheter ablation is associated with major adverse cardiac and cerebrovascular events (MACCE).

Methods

We retrospectively investigated 2,737 participants (74.4% men, mean age 63.4±10.3 years, 62.7% paroxysmal AF) who received first catheter ablation for AF and completed follow-up more than 3 months after the procedure from AF Frontier Ablation Registry, a multicenter cohort study in Japan. We evaluated an association between late recurrence of AF after catheter ablation and first MACCE in cox-regression hazard models adjusted for known risk factors. MACCE were defined as stroke/transient ischemic attack (TIA), cardiovascular events or all-cause death. Late recurrence was defined as AF relapse more than 3 months after the procedure.

Results

During a mean follow-up period of 25.2 months, 2,070 patients (75.6%) were free from AF after catheter ablation and 122 patients (4.5%) had MACCE (ischemic stroke 18 [14.8%], hemorrhagic stroke 16 [13.1%], TIA 7 [5.7%], hospitalization for heart failure 19 [15.6%], acute coronary syndrome 19 [15.6%], hospitalization for other cardiovascular events 24 [20%] and all-cause death 19 [15.6%]). The MACCE occurred significantly more frequently in the recurrence group than in non-recurrence group (7.5% vs. 3.5%; hazard ratio [HR] 1.85; 95% confidence interval [CI] 1.28–2.65; P=0.001) (Figure). Multivariate analysis revealed that baseline age (HR 1.05; 95% CI 1.03–1.08; P<0.001), heart failure (HR 1.76; 95% CI 1.17–2.66; P=0.007), old myocardial infarction (HR 4.49; 95% CI 2.59–7.81; P<0.001), non-ischemic cardiomyopathy (HR 2.56; 95% CI 1.47–4.46; P=0.001), left atrial diameter (HR 1.22 per 5-mm increase; 95% CI, 1.06–1.41; P=0.006) and recurrence of AF (HR 1.69; 95% CI 1.17–2.44; P=0.005) were independently associated with the incidence of MACCE after catheter ablation.

Conclusion

In the Japanese multicenter cohort of AF ablation, late recurrence of AF was independently associated with increased MACCE, suggesting the significance of sinus rhythm maintenance by catheter ablation.

Kaplan-Meier curves for MACCE

Funding Acknowledgement

Type of funding source: None

Nerve growth factor receptor is involved in maintaining homeostasis of pulmonary arterial hypertension

Introduction

Pulmonary arterial hypertension (PAH), characterized by vascular remodeling, is still disease with poor prognosis although many pulmonary vasodilators have been developed, and new mechanism of treatment for PAH is desired. Nerve growth factor receptor (Ngfr) is known to relate to inflammatory reaction and repair process in the damaged tissue. We have reported that Ngfr is associated to vascular remodeling in patients with acute coronary syndrome. However, it is unclear how Ngfr is involved in the pathogenesis of PAH.

Purpose

In this study, we investigated whether Ngfr relate to pathophysiology in PAH.

Methods

We estimated the frequency of Ngfr positive cells (% Ngfr+) in peripheral blood mononuclear cells obtained from PAH and non-PAH patients using flowcytometric analysis. In PAH patients, the hemodynamic parameters such as mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac index (CI) were obtained by right heart catheterization, and evaluated for correlation with the % Ngfr+.

Next, adult 8-week-old C57BL/6 (WT) mice and Ngfr knock out (KO) mice were exposed to chronic hypoxia (10% O2) or normoxia for 6 weeks. Then, mice were anesthetized and performed echocardiography and right heart catheterization. Then, mice were exsanguinated and blood sample was collected to evaluate the % Ngfr+ by flow cytometry. Right ventricular weight was measured and lung tissue was also collected for histological assessment and molecular pathway profiling.

Results

PAH (n=24) patients and non-PAH patients (n=17) were enrolled. The % Ngfr+ was significantly higher in PAH patients than that in non-PAH patients (0.056% versus 0.019%, p<0.0001). In PAH patients, the % Ngfr+ was correlated with severity of hemodynamic parameters such as mPAP (R=0.64 p<0.001), PVR (R=0.62 p<0.005), and CI (R=−0.48 p<0.05).

In WT mice, chronic hypoxia significantly increased the right ventricular systolic pressure and induced vascular medial thickness and fibrosis around the pulmonary artery. Flow cytometry analysis revealed that the % Ngfr+ was significantly increased in the hypoxia compared to that in the normoxia. Under hypoxic conditions, the right ventricular systolic pressure was significantly increased in Ngfr KO mice compared to that in WT mice. In histological analysis, hypoxia-induced peripheral vascular fibrosis and medial thickness was more severe in Ngfr KO than that in WT mice.

Conclusion

Circulating Ngfr-positive cells are associated with severity of PAH in patients. In the hypoxia-induced PH model, gene deletion of Ngfr shows the progression of the pathogenesis of PAH. These results suggest that circulating Ngfr-positive cells have an important role in the pathogenesis of PAH and may be a novel target for PAH therapy.

Funding Acknowledgement

Type of funding source: None

The outcome of ablation for non-paroxysmal atrial fibrillation targeting spatiotemporal electrogram dispersion compared with ganglionated plexi ablation

Background

Although catheter ablation targeting ganglionated plexi (GP) playing an important role in formation of triggers and substrates of atrial fibrillation (AF) has been reported as one of the effective ablation strategies in non-paroxysmal AF (non-PAF) patients, its effectiveness varies among the study groups. More recently, ablation targeting spatiotemporal electrogram dispersion (STED) areas, assumed to contain AF drivers in forms of rotational activation is proposed. However, the optimal ablation strategy for non-PAF is still controversial since the exact mechanisms of non-PAF are not well understood.

Purpose

To investigate the effectiveness of GP ablation for autonomic modification and STED ablation for modulation of AF drivers.

Methods

Consecutive 149 non-PAF patients who underwent STED ablation in our center were enrolled. We detected STED areas within the whole left and right atrium during AF using PentaRay®, and ablated them. If AF was terminated during STED ablation, we finished the procedure without burning the remaining STED areas. If not, electrical cardioversion was applied. The outcome was compared with that in consecutive 156 non-PAF patients undergoing GP ablation previously in our center.

Results

(1) The clinical characteristics were comparable between two groups (see Table). (2) A Kaplan-Meier curve showed that there was no significant difference between the freedom rates from non-PAF/non-paroxysmal atrial tachycardia (non-PAT) after single procedure in STED group and GP group (Figure, left). (3) However, the freedom rates from non-PAT in STED group was significantly lower than that GP group (Figure, right).

Conclusions

The recurrence type of atrial arrhythmia after ablation was remarkably different between ablation of STED and GP. STED ablation might eliminate fibrillatory conduction and control AF driver in patients with non-PAF.

Freedom from atrial arrhythmia

Funding Acknowledgement

Type of funding source: None

Novel index of arterial reflected waves, Arterial Velocity pulse Index, relates to muscle sympathetic nerve activity independent of Arterial Pressure volume Index in patients with hypertension

Background

Arterial reflected wave is determined by not only atherosclerosis but also sympathetic nerve activity. Recently, Arterial Velocity pulse Index (AVI), which is an index of arterial reflected waves, and Arterial Pressure volume Index (API), which is an index of volume of a conductive blood vessel, have been proposed as new index of arterial stiffness. However, it is unclear whether API and AVI would be associated with muscle sympathetic nerve activity (MSNA) in hypertensive subjects.

Purpose

The purpose of this study was to evaluate the correlation between AVI, API and MSNA in hypertensive subjects.

Method

41 hypertensive patients and 40 non-hypertensive subjects were included in this study. We performed a cross-sectional, observational study. Hypertension (HT) was defined as systolic blood pressure (SBP) ≥140 mmHg, diastolic blood pressure (DBP) ≥90 mmHg or medical treatment for HT. AVI and API was measured by NAS-1000 (Nihon Koden, Japan). MSNA, central sympathetic outflow to peripheral muscle, was recorded directly from peroneal nerve. MSNA was expressed by burst frequency (bursts/minute) and burst incidence (bursts/100heartbeats). Blood pressure, heart rate and MSNA were recorded simultaneously.

Results

Age, systolic and diastolic pressure were significantly higher in hypertensive patients compared to control (40±15 vs 61±13 years, p<0.001; 142±16 vs 113±9 mmHg, p<0.001; 81±14 vs 67±9 mmHg, p<0.001). MSNA and AVI were significantly augmented in hypertensive patients compared to control (34±11 vs. 23±6 bursts/min, p<0.05; 26±7 vs. 16±4, p<0.05). AVI was correlated with MSNA in each group (hypertension: r=0.59, P<0.001, non-hypertension: r=0.51, p<0.001). However, no correlation was shown between API and MSNA in each group (hypertension: r=0.22, p=0.15, non-hypertension: r=0.07, p=0.63). Multiple regression analysis also showed MSNA was significantly related with AVI but was not with API.

Conclusion

Our finding showed that AVI relates to MSNA independent of API in patients with hypertension. It suggested that Novel index of arterial reflected waves, AVI, is helpful to estimate augmented SNA in hypertensive subjects regardless of volume of a conductive blood vessel.

Funding Acknowledgement

Type of funding source: None

Rare SCN10A variants associated with cardiac conduction system diseases

Background

The genetic bases of cardiac conduction-system disease (CCSD) range from ion channelopathies to mutations in many other genes. Genome-wide association studies have shown common variants in SCN10A influence cardiac conduction. However, it has not yet to be determined whether vulnerability to CCSD is associated with rare coding sequence variation in the SCN10A gene.

Purpose

We sought to determine the clinical impact of rare variants in SCN10A in patients with CCSD and classified the variants according to the 2015 American College of Medical Genetics and Genomics (ACMG) standards and guidelines.

Methods

We performed screening for rare variants (minor allele frequency ≤0.001) in SCN10A in CCSD patients with an onset at a young age under 65 or those who had a family history of pacemaker implantation (PMI) (n=40; 18 female; mean age, 41±18 years). We transiently expressed engineered variants in ND 7/23 cells, and conducted whole-cell voltage clamp experiments to clarify the functional properties of the Nav1.8 current.

Results

We identified nine rare variants in SCN10A in 7 patients. Two patients were carriers of two rare variants in SCN10A and 5 were carriers of one rare variant in SCN10A. Four patients were affected with sinus node dysfunction, 1 were atrioventricular block, and 2 were both dysfunctions. We performed electrophysiological study for 8 of 9 rare variants. It demonstrated that 2 rare variants showed gain-of-function, and 3 rare variants showed loss-of-function. We finally determined 5 likely pathogenic variants in SCN10A in 5 patients (12.5%) according to the ACMG standards and guidelines. All 5 patients underwent a pacemaker implantation at an average age of 43±16.

Conclusions

These results demonstrate that SCN10A variants play a pivotal role in enhanced susceptibility of CCSD. We suggest the importance for screening SCN10A variants in clinical settings.

Funding Acknowledgement

Type of funding source: None

Bone marrow-derived NGFR+ cells regulate arterial remodeling and those poor mobilizations in peripheral blood in acute coronary syndrome predicts plaque progression at the non-targeted lesion

Background

In our previous 5-year cohort study, we demonstrated that low gene expression of nerve growth factor receptor (NGFR) in peripheral leucocytes in acute coronary syndrome (ACS) predicted repetitive coronary interventions at the de novo lesions. An NGFR-positive cell has been demonstrated to reside in bone marrow (BM) stromal fraction and to be increased in peripheral blood mononuclear cell (MNCs) fraction in patients with ischemic heart disease.

Purpose

To investigate whether the BM-NGFR+ cell is associated with arterial remodeling and the relationship between the levels of peripheral NGFR+ cells after ACS and coronary plaque progression in an experimental and prospective clinical study.

Methods and results

In an experimental study, 8-week-old C57B6/J wild type male mice were subjected to irradiation with 9.6 Gy and transplantation with BM (BMT) isolated from GFP-transgenic NGFR wild type (WT) or knock-out (KO) mice at day 1. Four weeks after BMT, the right carotid artery was ligated for 4 weeks. Induced neointimal area was increased (p<0.05), where cells under apoptosis were decreased (p<0.05) in NGFR-KO-BMT group compared to WT-BMT group (n=4). NGFR+ cells were not detected in wild type sham-operated artery, whereas in the ligated artery in WT-BMT group NGFR+ cells assembled in the developed neointima and exclusively presented double positive with GFP, but absent in NGFR-KO-BMT group (p<0.05, n=4). In a clinical study, thirty patients with ACS who underwent primary percutaneous coronary intervention (PCI) were enrolled. The peripheral blood sample was collected on days 0, 3 and 7, and 9 months follow-up and the number of NGFR+MNCs were measured by flowcytometric analysis. The plaque volume at non-targeted coronary lesion (non-TL:>5 mm proximal or distal to the implanted stents) were quantitatively analysed using gray-scale intravascular ultrasound (IVUS) and Q-IVUS™ software at the acute phase and 9 months follow-up. The number of NGFR+MNCs in peripheral blood was 1.5-fold increased at day 3 (0.064±0.056%) compared to day 0 (0.042±0.030%) (p<0.05). The change in normalized total plaque volume (TAVN) at non-TL at 9 months was negatively correlated with the number of NGFR+MNCs at day 0 (r=−0.51), day 3 (r=−0.51) and 9 months (r=−0.59) after ACS (p<0.05). Multiple regression analysis showed that NGFR+MNCs at day 0 (β=−0.48, p=0.01) and CRP (β=−0.53, P<0.01) are independent factors associating with TAVN change at non-TL at 9 months, regardless of LDL-cholesterol control level. ROC analysis revealed that NGFR+MNCs <0.049 at day 0 predicted the increase of TAVN with AUC 0.78; sensitivity 0.82 and specificity 0.67.

Conclusions

Bone marrow-derived peripheral NGFR+ cells negatively regulate arterial remodeling through appropriate apoptosis of neointimal cells and the peripheral level of NGFR+ cells in ACS predicts plaque progression at the non-targeted lesion.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): KAKENHI

Development of fluorescence-yield wavelength-dispersive x-ray absorption spectroscopy in the soft x-ray region for time-resolved experiments

A fluorescence-yield wavelength-dispersive x-ray absorption spectroscopy technique in the soft x-ray region, by which the x-ray absorption spectra are recorded without scanning the monochromator, has been developed. The wavelength-dispersed soft x rays, in which the wavelength (photon energy) continuously changes as a function of the position, illuminate the sample, and the emitted fluorescence soft x rays at each position are separately focused by an imaging optics onto each position at a soft x-ray detector. Ni L-edge x-ray absorption spectra for Ni and NiO thin films taken in the wavelength-dispersive mode are shown in order to demonstrate the validity of the technique. The development of the technique paves the way for a real-time observation of time-dependent processes, such as surface chemical reactions, with much higher gas pressure compared to the electron-yield mode, as well as under magnetic and electric fields.

SAT0113 DISCORDANCE OF CLINICAL REMISSION AND IMAGING REMISSION BY ULTRASONOGRAPHY IN PATIENTS WITH RHEUMATOID ARTHRITIS WITH BIOLOGIC AGENTS

Background:

Residual synovitis can be detected by sensitive modalities such as ultrasonography in patients with rheumatoid arthritis in clinical remission. On the other hand, a previous study has shown that ultrasound-guided treatment provides modest benefit compared to a conventional strategy aiming clinical remission in early patients. It is still unclear how discordant clinical remission is from imaging remission by ultrasonography in patients treated with biologic agents

Objectives:

To clarify the discordance between clinical remission and imaging remission in patients with rheumatoid arthritis treated with biologic agents.

Methods:

Patients with rheumatoid arthritis who were treated with biologic agents and in clinical remission defined as disease activity score for 28 joints (DAS28)<2.6 were enrolled. All patients were performed comprehensive ultrasound examination of 44 joints as well as physical examinations. Ultrasound images of gray scale (GS) and power doppler (PD) were evaluated with a semi-quantitative score of 0-3. Imaging remission with ultrasound was defined as no PD signal detected in any joints. Clinical information was collected from their medical charts.

Results:

A total of 41 patients were enrolled with 22 patients treated with tumor necrosis factor (TNF)-α inhibitors and 19 with interleukin (IL)-6 inhibitors. The mean age, female ratio, the mean disease duration, and the mean duration of clinical remission were 60 years old, 87%, 5.1 years and 11.5 years. The imaging remission by ultrasonography was observed only in 51.2 %. When patients were divided according to biologic agents, baseline characteristics including median age, disease duration and clinically remission duration were comparable between both groups, while the rates of seropositivity and the stage of radiological progression was higher in IL-6 group (seropositivity, p=0.04; radiological progression, p=0.02). The mean DAS28 was 1.93 in the TNFα group and 1.02 in the IL-6 group. The discordance of clinical remission and imaging remission was observed in 28.6% of the TNFα group and 71.4% of the IL-6 group (p=0.03). The residual synovitis scores of GS and PD in 44 joints were significantly lower in the TNFα than the IL-6 group (GS, 1.1±1.8 vs 4.7 ± 4.6, p<0.01; PD, 0.6 ± 1.3 vs 3.3 ± 3.5, p<0.01, respectively). A receiver operating characteristic curve demonstrated an optimal score of DAS28 that discriminated imaging remission as 1.89 in the TNFα group and 1.25 in the IL-6 group.

Conclusion:

Our results showed that there was substantial discordance between clinical remission and imaging remission, especially in the patients treated with IL-6 inhibitors. In patients treated with biologic agents, clinical remission should be assessed more stringently than the usual 2.6, and ulltrasound-guided management may be useful.

References:

[1]Smolen JS, et al. Ann Rheum Dis 2020;0:1–15.

[2]Iwamoto T, et al. Arthritis Care Res (Hoboken). 2014;66(10):1576-81

[3]Tanaka Y. Ann Rheum Dis 2010;69:1286 –91

[4]Kaneko Y, et al. Ann Rheum Dis 2018;77:1268–1275

[5]Brown AK, et al. Arthritis Rheum 2008;58: 2958 – 67.

Acknowledgments:

We would like to thank Harumi Kondo for their assistance.

Disclosure of Interests:

Yasushi Kondo: None declared, Yuko Kaneko Speakers bureau: Dr. Kaneko reports personal fees from AbbVie, personal fees from Astellas, personal fees from Ayumi, personal fees from Bristol-Myers Squibb, personal fees from Chugai, personal fees from Eisai, personal fees from Eli Lilly, personal fees from Hisamitsu, personal fees from Jansen, personal fees from Kissei, personal fees from Pfizer, personal fees from Sanofi, personal fees from Takeda, personal fees from Tanabe-Mitsubishi, personal fees from UCB, Shuntaro Saito: None declared, Yuichiro Ohta: None declared, Komei Sakata: None declared, Yumiko Inoue: None declared, Chihiro Takahashi: None declared, Kazuoto Hiramoto: None declared, Jun Inamo: None declared, Tsutomu Takeuchi Grant/research support from: Eisai Co., Ltd, Astellas Pharma Inc., AbbVie GK, Asahi Kasei Pharma Corporation, Nippon Kayaku Co., Ltd, Takeda Pharmaceutical Company Ltd, UCB Pharma, Shionogi & Co., Ltd., Mitsubishi-Tanabe Pharma Corp., Daiichi Sankyo Co., Ltd., Chugai Pharmaceutical Co. Ltd., Consultant of: Chugai Pharmaceutical Co Ltd, Astellas Pharma Inc., Eli Lilly Japan KK, Speakers bureau: AbbVie GK, Eisai Co., Ltd, Mitsubishi-Tanabe Pharma Corporation, Chugai Pharmaceutical Co Ltd, Bristol-Myers Squibb Company, AYUMI Pharmaceutical Corp., Eisai Co., Ltd, Daiichi Sankyo Co., Ltd., Gilead Sciences, Inc., Novartis Pharma K.K., Pfizer Japan Inc., Sanofi K.K., Dainippon Sumitomo Co., Ltd.

P942 Outcome prediction by exercise stress echocardiography and cardiopulmonary exercise testing assessment in patients with heart failure

Background

Cardiopulmonary exercise testing (CPX) is essential to the assessment of functional impairment and prognosis in patients with heart failure (HF). Peak oxygen consumption (peak VO2) continues to be considered the gold standard for assessing prognosis in HF. The minute ventilation-carbon dioxide production (VE-VCO2) slope has recently demonstrated prognostic significance in patients with HF. Ergometer stress echocardiography (Erg-Echo) is useful to evaluate the exercise-induced pulmonary hypertension and the potential cardiac dysfunction that are difficult to evaluate in the resting state.

Objective

The aim of this study is to evaluate the relationship between CPX and Erg-echo indices, and the usefulness of Erg-echo to determine the severity of cardiac dysfunction and the prognosis in patients with HF.

Methods

We studied 58 patients with HF (age 65.2 ± 11.9 years) and performed CPX and Erg-Echo. The peak VO2 and the VE-VCO2 slope were measured by CPX. Cardiac output (CO) and estimated mean pulmonary artery pressure (mPAP) were measured by Erg-Echo at rest and peak exercise load, and the change ratio (ΔmPAP / ΔCO) were calculated. We evaluated the clinical outcome during a1 year period.

Results

The ΔmPAP / ΔCO was significantly correlated with the peak VO2 (R = -0.6767, P &lt;0.0001) and the VE-VCO2 slope (R = 0.6809, P &lt;0.0001). Cardiovascular events (1 patient of cardiovascular death, 8 patients of re-hospitalization due to HF, 4 patients of myocardial ischemia, 2 patients of Cardiac Resynchronization Therapy (CRT) devices implantation, 1 patient of ventricular tachycardia) developed in 16 of the 58 patients (27.5%: Group CE) during the 1 year. The peak VO2 was significantly lower (12.1 ± 2.5 vs. 16.1 ± 3.1ml/min/kg, P &lt;0.0001) and the VE-VCO2 slope was significantly higher (41.1 ±. 12.3 vs. 31.8 ± 6.1ml/ml, P &lt;0.0001) in Group CE compared to the other 42 patients (Group N). The ΔmPAP was significantly higher (19.1 ± 4.4 vs. 14.9 ± 6.4, P = 0.0408) and the ΔCO was significantly lower (2.4 ± 1.2 vs. 4.1 ± 2.0, P = 0.0078), and the ΔmPAP / ΔCO was significantly higher (9.7 ± 4.6 vs. 4.4 ± 2.4, P &lt;0.0001) in Group CE compared to Group N.

Conclusions

The ΔmPAP/ ΔCO by Erg-Echo is useful to evaluate the severity of cardiac dysfunction and the prognosis of HF patients.

P1802 Prevalence and prognostic significance of pulmonary artery aneurysms in patients with pulmonary artery hypertension

Background

Pulmonary artery aneurysm (PAA) occurs in some patients with pulmonary arterial hypertension (PAH) and can be accompanied by various complications.

Objective

The aim of the this study is to evaluate the characteristics of cardiac dysfunction and the prognostic impact of PAA by analysing the outcome of patients with PAH complicated by PAA.

Methods

We performed echocardiography and right-heart catheterization in 130 PAH patients. We measured the maximum dimensions of the main pulmonary artery (MPA) trunk. We evaluated the right ventricular (RV) function and the five-year prognosis of patients with PAA.

Results

The maximum MPA trunk diameter of &gt;40 mm by echocardiography was defined as PAA. PAA appeared in 32 of the 130 PAH patients (24.6%: Group PAA), other 98 patients were defined as Group non-PAA. Systolic pulmonary artery pressure (76 ±18 vs. 61 ± 21 mmHg, P = 0.0008) and mean right atrial pressure (10.0 ± 8.1 vs. 5.4 ± 3.8 mmHg, P &lt; 0.0001) were significantly higher in Group PAA than in Group non-PAA. RV end-diastolic area index was significantly larger (37.3 ± 8.8 vs. 32.3 ± 7.8 mmHg, P = 0.0048), and RV fractional area change (32 ± 8 vs. 36 ± 9 %, P = 0.0176) and RV longitudinal strain amplitude (-16 ±5 vs. -20 ± 6, P = 0.0017) were significantly lower in Group PAA than those in Group non-PAA. During the five-year follow-up period, 20 patients (15%) died. The five-year mortality rate was significantly higher in Group PAA compared to Group non-PAA (30% vs. 10%, P = 0.007).

Conclusion

In PAH patients with PAA, RV dysfunction was more severe and the prognosis was poor. Assessment of PAA can be a useful index for the extraction of high-risk PAH patients.

3073Leveraging transcriptome sequencing for detecting novel disease-related pathways using human cardiac sarcoidosis myocardium biopsies

Background/Introduction

Cardiac sarcoidosis (CS) is one of the main causes of poor outcomes in patients with sarcoidosis, a systemic granulomatous disorder of complex etiology including a genetically susceptible host and specific exposure to disease-triggering antigens. Recently, transcriptome analysis using sarcoidosis peripheral monocytes was reported to be useful for exploring genetic susceptibility and novel disease-causing pathways. However, transcriptome sequencing has not been used to explore disease-related genes and pathways directly using human CS myocardial biopsies.

Purpose

This study aimed to identify transcriptome profiles and novel disease-related pathways of CS by comparing human CS myocardial biopsies with control samples using ribonucleic acid (RNA) sequencing (RNA-Seq).

Methods

We assessed 30 patients with suspected myocardial disorders who underwent transcatheter endomyocardial biopsies at our University Hospital, Japan. Of those, 7 were clinically diagnosed with CS, 9 with hypertrophic cardiomyopathy (HCM), and 14 with dilated cardiomyopathy (DCM). Messenger RNAs were extracted from cardiac muscle biopsies using the Ovation SoLo RNA-Seq System (NuGEN Technologies), according to the manufacturer's instructions. Sequencing was performed with coverage of approximately 20 million reads per sample using Illumina HiSeq 2000. Sequencing reads were mapped using the STAR 2-pass method with GRCh37 as the reference. The DESeq2 R package (version 3.8) was used for further analyses. Principal component analysis (PCA) on gene expression was conducted for detecting outliers such as non-muscular samples. Differential gene expression analysis was performed between the 7 patients with CS and 23 patients with cardiomyopathy (HCM and DCM, non-CS). Gene Ontology (GO) enrichment analysis was conducted to estimate possible disease-related pathways.

Results

We successfully sequenced 60 myocardial biopsy samples (original and biological duplicates) from 30 CS patients. Of these, 2 outlier samples shown by the PCA plot were removed, and 58 were used for further analyses. We found 243 genes that were differentially expressed between CS patients and non-CS patients. Top-rated genes were RP11–366M4.8, RELN, S100A6, WASF3and UCHL1. Pathway analysis using GO demonstrated enrichment oflymphocyte activation (P=4.8x10–16), organelle fission (P=6.1x10–14), the M phase of the mitotic cell cycle (P=2.2x10–13), nuclear division (P=2.4x10–13), mitosis (P=2.4x10–13) and T-cell activation pathways (P=1.2x10–12).

Conclusions

Our differential gene expression and pathway analysis results using human CS myocardial biopsies suggested that lymphocyte activation, specifically the T-cell activation pathway, is linked to CS pathogenesis. Further studies are needed to decipher the role of specific genes related to genetic susceptibility and/or pathways associated with CS occurrence.

P6234The relationship of alcohol consumption with risk factors of coronary heart disease and the intake of macro- and micro-nutrients in Japanese: the INTERLIPID study

Background

Many studies have reported the J-shaped relationship between alcohol consumption and coronary heart disease (CHD) risk; therefore, light-drinkers is generally recognized to be associated with the lower risk of CHD. However, the mechanisms of lower risk for CHD in light-drinkers are still unclear. Alcohol drinking status is likely to be associated with not only CHD risk factors but also dietary intake. Nevertheless, few studies report these relationships in detail.

Purpose

The purpose of this study is to evaluate the relationships of alcohol drinking status with CHD classical risk factors and the intake of macro- and micro- nutrients in Japanese.

Methods

Study participants were 1,090 Japanese men and women aged 40–59 years from The INTERLIPID study excepted for 55 individuals who had missing data (n=26) and were past-drinkers (n=29). Alcohol consumption was assessed with two 7-day alcohol records, and average ethanol intake (per week) was calculated. Participants were classified into following 4 groups: non-drinkers (0g/week), light-drinkers (<100 g/week), moderate-drinkers (100–299 g/week), and heavy-drinkers (≥300 g/week). Serum LDL and HDL cholesterol, blood pressure (BP), the prevalence of hypertension and dyslipidemia, and smoking status were assessed as CHD risk factors. The intake of energy and macro- and micro-nutrients were evaluated from the four-timed in-depth 24-hr dietary recalls. Nutrient intake densities were calculated per total energy intake without alcohol. The analysis of variance and chi-squared test were used to evaluate the relations of alcohol status with CHD risk factors and nutrient intake.

Results

Serum HDL cholesterol levels increased and LDL cholesterol levels decreased with increasing alcohol consumption. Systolic and diastolic BP increased with increasing alcohol consumption. J-shaped relationships with alcohol consumption were observed for the proportion of current smoker, number of cigarettes, and the prevalence of hypertension; that is, light-drinkers was lowest among all groups. The prevalence of dyslipidemia was the highest in non-drinkers, and decreased with increasing alcohol consumption. In heavy-drinkers, total energy (kcal/day) was the highest, but energy intake without alcohol (kcal/day) was the lowest. For macronutrients, the intake of carbohydrate (%kcal) decreased, and the intakes of total and animal protein (%kcal) increased with increasing alcohol consumption. The intakes of total cholesterol (mg/1000kcal) and sodium (mg/1000kcal) increased, and total fiber (g/1000kcal) decreased with increasing alcohol consumption. These associations were similar in men and women.

Conclusions

Alcohol consumption was related with not only CHD classical risk factors but also the intake of macro- and micro-nutrients. Non-drinkers had a higher proportion of some CHD risk factors than light-drinkers. These results might influence on J-shaped relationship between alcohol consumption and CHD risk.

Acknowledgement/Funding

1: Ministry of Education, Science, Sports, and Culture of Japan, 2: National Institutes of Health, Bethesda, MD, USA

P1535Clinical impact of carotid plaque score rather than carotid intima-media thickness on atherosclerotic cardiovascular disease

Background

Carotid intima-media thickness (cIMT) assessed by ultrasound has been widely accepted as a surrogate marker of atherosclerotic cardiovascular disease. On the other hand, carotid plaque score (cPS) reflecting throughout the carotid artery plaque burden may be better marker.

Methods

We retrospectively examined 2,035 patients who underwent carotid ultrasonography between January 2006 and December 2015 at our University Hospital. Median follow-up period was 4 years. We used Cox models that adjusted for established risk factors of ASCVD, including age, gender, hypertension, diabetes, smoking, and serum lipids to assess the association of cIMT as well as cPS with major adverse cardiac events (MACE). MACE was defined as all-cause mortality or rehospitalization for a cardiovascular-related illness

Results

During follow-up, 243 participants experienced MACE. After adjustment for established risk factors, cPS was associated with MACE (hazard ratio [HR] = 3.38 for top quintile vs. bottom quintile of cPS; 95% confidence interval [CI] 1.82 to 6.27; P-trend = 1.4×10–8), while cIMT was not (HR = 0.88, P=0.57). Addition of the cPS to established risk factors significantly improved risk discrimination (C-index 0.726 vs. 0.746; P=0.017)

Conclusion

As a marker, cPS, rather than cIMT can identify 20% of individuals who are at more than three-fold increased risk for MACE. Targeting diagnostic or therapeutic interventions to this subset may prove clinically useful.

Spherical tarball particles form through rapid chemical and physical changes of organic matter in biomass-burning smoke

Biomass burning (BB) emits enormous amounts of aerosol particles and gases into the atmosphere and thereby significantly influences regional air quality and global climate. A dominant particle type from BB is spherical organic aerosol particles commonly referred to as tarballs. Currently, tarballs can only be identified, using microscopy, from their uniquely spherical shapes following impaction onto a grid. Despite their abundance and potential significance for climate, many unanswered questions related to their formation, emission inventory, removal processes, and optical properties still remain. Here, we report analysis that supports tarball formation in which primary organic particles undergo chemical and physical processing within ∼3 h of emission. Transmission electron microscopy analysis reveals that the number fractions of tarballs and the ratios of N and O relative to K, the latter a conserved tracer, increase with particle age and that the more-spherical particles on the substrates had higher ratios of N and O relative to K. Scanning transmission X-ray spectrometry and electron energy loss spectrometry analyses show that these chemical changes are accompanied by the formation of organic compounds that contain nitrogen and carboxylic acid. The results imply that the chemical changes increase the particle sphericity on the substrates, which correlates with particle surface tension and viscosity, and contribute to tarball formation during aging in BB smoke. These findings will enable models to better partition tarball contributions to BB radiative forcing and, in so doing, better help constrain radiative forcing models of BB events.