Does the same lesion index mean the same efficacy and safety profile: influence of the differential power, time, and contact force on the lesion size and steam pops under the same lesion index

BACKGROUND

The lesion index (LSI) helps predict the lesion size and is widely used in ablation of various types of arrhythmias. However, the influence of the ablation settings on the lesion formation and incidence of steam pops under the same LSI value remains unclear.

METHODS

Using a contact force (CF) sensing catheter (TactiCath™) in an ex vivo swine left ventricle model, RF lesions were created with a combination of various power steps (30 W, 40 W, 50 W) and CFs (10 g, 20 g, 30 g, 40 g, 50 g) under the same LSI values (5.2 and 7.0). The correlation between the lesion formation and ablation parameters was evaluated.

RESULTS

Ninety RF lesions were created under a target LSI value of 5.2, and eighty-four were developed under a target LSI value of 7.0. In the LSI 5.2 group, the resultant lesion size widely varied according to the ablation power, and a multiple regression analysis indicated that the ablation energy delivered was the best predictor of the lesion formation. To create a lesion depth > 4 mm, an ablation energy of 393 J is the best cutoff value, suggesting a possibility that ablation energy may be used as a supplemental marker that better monitors the progress of the lesion formation in an LSI 5.2 ablation. In contrast, such inconsistency was not obvious in the LSI 7.0 group. Compared with 30 W, the 50-W ablation exhibited a higher incidence of steam pops in both the LSI 5.2 and 7.0 groups.

CONCLUSIONS

The LSI-lesion size relationship was not necessarily consistent, especially for an LSI of 5.2. To avoid any unintentional, weak ablation, the ablation energy may be a useful supportive parameter (393 J as a cutoff value for a 4-mm depth) during ablation with an LSI around 5.2. Thanks to a prolonged ablation time, the LSI-lesion size relationship is consistent for an LSI of 7.0. However, it is accompanied by a high incidence of steam pops. Care should be given to the ablation settings even when the same LSI value is used.

Age-dependent contribution of intrinsic mechanisms to sinoatrial node function in humans

Average beat interval (BI) and beat interval variability (BIV) are primarily determined by mutual entrainment between the autonomic-nervous system (ANS) and intrinsic mechanisms that govern sinoatrial node (SAN) cell function. While basal heart rate is not affected by age in humans, age-dependent reductions in intrinsic heart rate have been documented even in so-called healthy individuals. The relative contributions of the ANS and intrinsic mechanisms to age-dependent deterioration of SAN function in humans are not clear. We recorded ECG on patients (n = 16 < 21 years and n = 23 41-78 years) in the basal state and after ANS blockade (propranolol and atropine) in the presence of propofol and dexmedetomidine anesthesia. Average BI and BIV were analyzed. A set of BIV features were tested to designated the "signatures" of the ANS and intrinsic mechanisms and also the anesthesia "signature". In young patients, the intrinsic mechanisms and ANS mainly contributed to long- and short-term BIV, respectively. In adults, both ANS and intrinsic mechanisms contributed to short-term BIV, while the latter also contributed to long-term BIV. Furthermore, anesthesia affected ANS function in young patients and both mechanisms in adult. The work also showed that intrinsic mechanism features can be calculated from BIs, without intervention.

Online Adaptive Radiotherapy for Pharyngeal Cancer: Dose-Volume Histogram Analysis between Adapted and Scheduled Plan

PURPOSE/OBJECTIVE(S)

The present study aimed to evaluate whether online adapted plan with artificial intelligence (AI) driven work flow could be used in clinical settings with variable changes of the targets and organs at risk (OARs) for pharyngeal cancer.

MATERIALS/METHODS

Ten patients with pharyngeal cancer who underwent chemoradiotherapy at our institution between January and July 2020 were included for the analysis. All patients had been previously aligned daily with cone-beam computed tomography (CBCT) and treated by O-ring Linac. A simulated treatment was performed on the treatment emulator. Weekly fractions, once in every 4-5 fractions, were simulated in the treatment emulator for each patient using their previous on-treatment CBCTs. The dataset was divided into three groups according to the treatment period (1st-2nd week, 20 CBCTs), middle (3rd-4th week, 20 CBCTs), and late (5th-7th week, 30 CBCTs) period. In the present study, all of reference plan generation in treatment emulator were created on the initial plans of two-step method using 12 equidistant field IMRT. The prescribed dose was 70 Gy in 35 fractions and normalized to the dose of 68.6 Gy (98% dose) to 95% of the planning target volume (PTV). The adaptation process on treatment emulator includes auto-segmentation of daily anatomy, calculation of the dose in scheduled plans using the same monitor units and optimization and calculation of the dose in adapted plan. Dose-volume histogram (DVH) parameters between adapted and scheduled plans in terms of PTV (D98%, D95%, D50% and D2%), spinal cord (Dmax and D1cc), brain stem (Dmax), ipsilateral and contralateral parotid glands (Dmedian and Dmean) were evaluated in each period.

RESULTS

D98% of PTV of adapted plan was significantly higher than that of scheduled plan in early and middle period (p = 0.02 and <0.01, respectively). D95% of PTV of adapted plan was significantly higher than that of scheduled plan in all periods (p<0.01). D2% of PTV of adapted plan was significantly lower than that of scheduled plan in all periods (p = 0.04, 0.04 and 0.02 in each period, respectively). There was not significant difference in D50% of PTV between adapted and scheduled plan in all periods. In terms of OARs, Dmax of spinal cord of adapted plan was significantly lower than that of scheduled plan in all periods (p<0.01). Similarly, D1cc of spinal cord of adapted plan was lower than that of scheduled plan. Dmean of ipsilateral and contralateral parotid glands of adapted plan were lower than those of scheduled plan in the late period (p<0.01 and 0.03, respectively).

CONCLUSION

The present study revealed that adapted plan with AI driven work flow could create dosimetrically better plans for pharyngeal cancer compared to scheduled plan. It was suggested that online adaptive radiotherapy could be necessary to maintain PTV coverage while reducing the dose to OARs in all periods for pharyngeal cancer.

The Development and Evaluation of an All-Purpose Bolus for Radiotherapy

PURPOSE/OBJECTIVE(S)

The purpose of this study was to develop on a new bolus (HM bolus) which had tissue equivalence, transparency, reusability, and free shaping at approximately 40°C for excellent adhesion, and to evaluate its features could be satisfy ideal bolus conditions for clinical use.

MATERIALS/METHODS

The newly developed HM bolus was controlled to prevent phase separation by adjusting the contents of ethylene propylene rubber, styrene, butadiene rubber, thermoplastic resin, temperature-sensitive adjuster, and silica. The element ratios (wt%) in the HM bolus are H: 10.2%, C: 63.5%, O: 17.1%, and Si: 9.2%. The density was adjusted to 0.96 g cm-3. We evaluated dose characteristics, a vinyl gel sheet bolus (Gel bolus) and HM bolus placed on a water-equivalent phantom were used to obtain the percent depth dose (PDD) of electron (6 MeV, 9 MeV) and photon (4 MV,6 MV) beams. The average dose difference of the HM bolus and Gel bolus was calculated. The Gel bolus, a soft rubber bolus (SR bolus), and HM bolus were placed in adherence to a pelvic phantom. CT images taken after shaping and 1, 2, and 3 weeks after shaping were used to evaluate the adhesion and reproducibility using air gap and dice similarity coefficient (DSC) metrics. The visibility of letters (maximum: 80 pt, minimum: 10 pt) through a plate-shaped bolus and the visibility of markers when each bolus was set up on the pelvic phantom under normal room lighting were evaluated.

RESULTS

The average dose difference for electron beams was 0.16% ± 0.79% and photon beams was 0.06% ± 0.34%, both within 1% of the PDD results. The HM bolus showed the same build-up effect and dose characteristics as the Gel bolus. The mean air gap values for the Gel bolus, SR bolus, and HM bolus were 96.02 ± 43.77 cm3, 34.93 ± 21.44 cm3, and 4.40 ± 1.50 cm3 44, respectively. The mean DSC values for the Gel bolus, SR bolus, and HM bolus were 0.363 ± 0.035, 0.556 ± 0.042, and 0.837±0.018. The HM bolus showed the smallest air gap at all time points and the DSC closest to 1. Excellent adhesion was observed in the CT simulation and during the treatment period. The letter visibility through the HM bolus and Gel bolus was sufficient, and when the HM bolus was set up on the pelvic phantom, the markers that were completely invisible with the SR bolus were visible.

CONCLUSION

We succeeded in developing an all-purpose bolus with unique characteristics for clinical use. The HM bolus had the same build-up effect and dose characteristics as a Gel bolus. Therefore, it can be used for CT simulation and dose calculation. The other advantages of the new bolus are tissue equivalence, transparency, reusability, and free shaping at approximately 40°C, providing excellent adhesion at each setup during the treatment period.

Anti-Inflammatory Actions of Expectorants in a Rat Carrageenan-Induced Footpad Edema Model

S-Carboxymethyl-L-cysteine (SCMS) exhibits sputum-regulating and anti-inflammatory actions. Previous studies reported the anti-inflammatory effects of SCMS on chronic inflammatory diseases, but no study has examined these effects on acute inflammatory diseases. In this study, we investigated the anti-inflammatory effects of SCMS in a rat carrageenan-induced footpad edema model, which is routinely used as an acute inflammation model. Expectorants were administered to rats with footpad edema induced by subcutaneously administering 1%λ-carrageenan to the footpad of the left posterior limb, and the dose dependency of the anti-inflammatory effects was evaluated. As a result, even when the dose of SCMS was increased to 400 mg/kg, there were no inhibitory effects on edema. Furthermore, we examined the inhibitory effects of other expectorants (ambroxol hydrochloride, N-acetyl-L-cysteine, L-cysteine ethylester hydrochloride, and L-cysteine methylester hydrochloride), which were reported to exhibit anti-inflammatory effects on chronic inflammation, on edema. However, none of these expectorants inhibited edema.

Probing Superatomic Orbitals of Sc-Doped and Undoped Silver Cluster Anions via Photoelectron Angular Anisotropy

Valence s electrons in alkali- or coinage-metal clusters are conceived to delocalize over the metal frameworks. The electrons occupy so-called superatomic orbitals (SAOs, i.e., 1S, 1P, 1D, 2S, 1F, ...), which provide an essential picture for understanding the size-dependent, unique properties of these metal clusters. While such electronic shells are unambiguously identified in their photoelectron spectra and supported by electronic structure calculations, characterization of SAOs in heteroatom-doped metal clusters has remained elusive as the doping significantly affects its energy levels and even alters the ordering of SAOs. Here, we present a photoelectron imaging study to explore SAOs formed in Sc-doped and undoped silver cluster anions, Ag_NSc^- (N = 15, 16) and Ag_N^- (N = 18, 19). Photoelectron angular distributions from their outermost SAOs are clearly visualized, whose characters are analyzed with the aid of density functional theory calculations. The present methodology enables us to explore not only the quantized energy levels but also the spatial distributions of SAOs formed in various metal cluster anions.

Combination of heat-killed Lactiplantibacillus plantarum YIT 0132 (LP0132) and oral immunotherapy in cow's milk allergy: a randomised controlled trial

Safer and more effective cow milk (CM)-oral immunotherapy that does not induce allergic reactions has not yet been standardised. We sought to explore the efficacy and feasibility of a combination of heat-killed Lactiplantibacillus plantarum YIT 0132 (LP0132) and oral immunotherapy for treating IgE-mediated cow milk allergy (CMA). We conducted a 24-week, double-blind, randomised (1:1), two-arm, parallel-group, placebo-controlled, phase 2 trial of LP0132 intervention for treating IgE-mediated CMA in children aged 1-18 years (n=60) from January 29, 2018 to July 12, 2019 in Tokyo, Japan. Participants were randomly assigned to the LP0132 group receiving citrus juice fermented with LP0132 or to the control group receiving citrus juice without. Both groups received low-dose slow oral immunotherapy with CM. The primary outcome was improved tolerance to CM, proven by the CM challenge test at 24 weeks. Secondary outcomes were changes in serum biomarkers of serum-specific β-lactoglobulin-IgE (sIgE) and β-lactoglobulin-IgG4 (sIgG4). Exploratory outcomes included changes in serum cytokine levels and gut microbiota composition. A total of 61 participants were included. Finally, 31 children were assigned to the LP0132 group and 30 to the control group, respectively. After the intervention, 41.4 and 37.9% of the participants in the LP0132 and control groups, respectively, showed improved tolerance to CM. In serum biomarkers after the intervention, the sIgG4 level was significantly higher, and interleukin (IL)-5 and IL-9 were significantly lower, in the LP0132 group than in the control group. In the gut microbiome, the α-diversity and Lachnospiraceae increased significantly in the LP0132 group, and Lachnospiraceae after the intervention was significantly higher in the LP0132 group than in the control group. In conclusion, low-dose oral immunotherapy with modulating gut microbiota might be a safer and more effective approach for treating cow's milk allergy.

Detailed investigation of the lesion formation with a novel contact force sensing catheter with a mesh‐shaped irrigation tip

Background

Recently, a novel contact force (CF) sensing catheter with mesh-shaped irrigation tip (TactiFlex SE, Abbott) was invented and is expected to be useful for safe and effective radiofrequency ablation. However, this catheter's detailed characteristics of the lesion formation are unknown.

Methods

With an in vitro model, TactiFlex SE and its predecessor, FlexAbility SE, were used. A cross-sectional analysis of 60 s lesions (combination of various energy power settings [30, 40, and 50 W], and CFs [10, 30, and 50 g]) and longitudinal analysis (combination of various powers [40 or 50 W], CFs [10, 30, and 50 g] and ablation times [10, 20, 30, 40, 50, and 60 s]) of both catheters were analyzed and compared.

Results

One hundred eighty RF lesions were created in protocol 1 and 300 in protocol 2. The lesion formation, impedance changes, and steam pops characteristics were similar between the two catheters. Higher CFs were related to higher incidences of steam pops. A nonlinear, time-dependent increase in the lesion depth and diameter was observed for all power and CF settings, and linear, positive correlations between the RF delivery time and lesion volume were observed for all power settings. Compared with 40 W, a 50 W ablation created greater lesions. Longer durations with higher CF settings had a higher steam pop incidence.

Conclusions

The lesion formation and incidence of steam pops with TactiFlex SE and FlexAbility SE were similar. A 40 or 50 W ablation with careful CF control not to exceed 30 g in addition to monitoring impedance drops was required to safely create transmural lesions.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Efficient Gene Knockout in Salivary Gland Epithelial Explant Cultures

We have developed methods to achieve efficient CRISPR-Cas9-mediated gene knockout in ex vivo mouse embryonic salivary epithelial explants. Salivary epithelial explants provide a valuable model for characterizing cell signaling, differentiation, and epithelial morphogenesis, but research has been limited by a paucity of efficient gene perturbation methods. Here, we demonstrate highly efficient gene perturbation by transient transduction of guide RNA-expressing lentiviruses into Cas9-expressing salivary epithelial buds isolated from Cas9 transgenic mice. We first show that salivary epithelial explants can be cultured in low-concentration, nonsolidified Matrigel suspensions in 96-well plates, which greatly increases sample throughput compared to conventional cultures embedded in solidified Matrigel. We further show that salivary epithelial explants can grow and branch with FGF7 alone, while supplementing with insulin, transferrin, and selenium (ITS) enhances growth and branching. We then describe an efficient workflow to produce experiment-ready, high-titer lentiviruses within 1 wk after molecular cloning. To track transduced cells, we designed the lentiviral vector to coexpress a nuclear fluorescent reporter with the guide RNA. We routinely achieved 80% transduction efficiency when antibiotic selection was used. Importantly, we detected robust loss of targeted protein products when testing 9 guide RNAs for 3 different genes. Moreover, targeting the β1 integrin gene (Itgb1) inhibited branching morphogenesis, which supports the importance of cell-matrix adhesion in driving branching morphogenesis. In summary, we have established a lentivirus-based method that can efficiently perturb genes of interest in salivary epithelial explants, which will greatly facilitate studies of specific gene functions using this system.

Ablation characteristics and incidence of steam pops with a novel, surface temperature-controlled ablation system in an ex vivo experimental model

BACKGROUND

A novel irrigation catheter (QDOT MICRO™) has been introduced, which enables a surface temperature-controlled ablation combined with tip cooling. However, the detailed description of its complex behavior and effect on the incidence of pops and lesion formation remains elusive. This study aimed to systematically investigate the ablation characteristics, feedback behavior, and incidence of steam pops in a simplified ex vivo swine model.

METHODS

Using swine ventricular tissue perfused with saline at 37°C, we systematically created lesions with 4×3 combinations of the wattage (20, 30, 40, and 50 W) and contact force (CF, 10, 30, and 50 g). Ablation was continued for either 120 s or until a steam pop occurred and repeated 10 times with each setting. The lesion geometry, ablation index, feedback dynamics, and conditions underlying the steam pops were measured and analyzed.

RESULTS

Steam pops occurred particularly frequently in combinations of a low CF and high power (10 g vs. 30 g+50 g [p < .0001]; 40 W+50 W vs. 20 W+30 W [p < .0001]). Failure to activate a feedback process was associated with a 5.1 times higher incidence of steam pops (21/109 vs.11/11, [95% CI 3.499-7.716], p < .0001). The wattage feedback was particularly evident with a high CF (30 and 50 g) and high initial wattage (40 and 50 W). The average delivered wattage at 27 W predicted the occurrence of steam pops.

CONCLUSION

The temperature-controlled ablation with the QDOT MICRO™ demonstrated a complex feedback behavior, which contributed to a reduced incidence of steam pops and prolonged lead time to the pops.

Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae

Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is extremely variable on various timescales^1-3. This variability seems mostly random, although some quasi-periodic oscillations (QPOs), implying systematic processes, have been reported in blazars and other AGN. QPOs with timescales of days or hours are especially rare⁴ in AGN and their nature is highly debated, explained by emitting plasma moving helically inside the jet⁵, plasma instabilities^6,7 or orbital motion in an accretion disc^7,8. Here we report results of intense optical and γ-ray flux monitoring of BL Lacertae (BL Lac) during a dramatic outburst in 2020 (ref. ⁹). BL Lac, the prototype of a subclass of blazars¹⁰, is powered by a 1.7 × 10⁸ M_Sun (ref. ¹¹) black hole in an elliptical galaxy (distance = 313 megaparsecs (ref. ¹²)). Our observations show QPOs of optical flux and linear polarization, and γ-ray flux, with cycles as short as approximately 13 h during the highest state of the outburst. The QPO properties match the expectations of current-driven kink instabilities⁶ near a recollimation shock about 5 parsecs (pc) from the black hole in the wake of an apparent superluminal feature moving down the jet. Such a kink is apparent in a microwave Very Long Baseline Array (VLBA) image.

POS0530 MOLECULAR SIGNATURE IN SUSTAINED CLINICAL REMISSION INDUCED BY TOCILIZUMAB IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Clinical remission is a clinical goal in the treatment of rheumatoid arthritis (RA). Sustained, biologics-free and true remission is an unachieved goal of the “treat-to-target” approach in most patients, and the determinants for achievement are still unclear. In our recent prospective study using multiomics analysis, we proposed that a molecular signature in peripheral whole blood can be a predictor for subsequent disease activity or activities of daily living.1 We also showed that tocilizumab (TCZ) induced deep clinical remission associated with gene expression in peripheral CD4+ T cells.2

Objectives

To consolidate and expand our hypothesis, we investigated the significance of molecular signatures in sustained remission in a larger scale cohort.

Methods

To build and validate the diagnostic model, we collected 73 peripheral blood samples from 30 patients with active RA, 30 patients in clinical remission induced by TCZ and 13 healthy controls. We then collected another 23 samples at a point before TCZ was halted due to sustained clinical remission. In total, 96 samples were analyzed by a multiomics platform, which included RNA sequencing and comprehensive proteomics.

Results

We first developed an optimized partial least-squares regression (PLSR) model using data from 5,436 genes and 255 proteins extracted in our previous model.1 The odds ratio in the model clearly reflected the clinical state with high fidelity (Figure 1). In that study, TCZ induced nearly half of the patients with clinical remission into molecular remission, with an odds ratio of less than zero. To clarify the characteristics of the molecular signature at sustained clinical remission under TCZ continuation, 23 samples were applied to the model. The odds ratio was largely the same as that for clinical remission. Next, we investigated the association with disease flare after cessation of TCZ. At some points before cessation, the median odds ratio in patients who experienced disease flare after stopping TCZ tended to be higher than that in patients with sustained remission after stopping TCZ in the transcriptomics model but not in the proteomics model. Thirty-five differentially expressed genes were identified between the two groups under the conditions of a >1.5-fold change and P-value<0.05.

Figure 1.

Odds ratio in the partial least-squares regression model using transcriptomics (A) and proteomics (B) data from rheumatoid arthritis and healthy control groups

Conclusion

Our larger scale study validated the idea in our previous study that TCZ induces molecular remission. A certain substantial gap associated with prognosis after quitting TCZ may exist as a molecular signature of sustained clinical remission induced by TCZ. These multiomics data sets enable us to understand sustained clinical remission at a molecular level.

References

[1]Nat Commun. 9(1):2775, 2018, 2) Sci Rep.11(1):16691, 2021

Graphs:

Acknowledgements

We acknowledge funding by Chugai Pharmaceutical Co., Ltd.

Disclosure of Interests

Nobuhiko Kajio: None declared, Katsuya Suzuki Speakers bureau: AbbVie, AsahiKasei, Astellas, Ayumi, Bristol-Myers Squibb, Chugai, Eisai, Eli Lilly, Gilead, Janssen, Mitsubishi Tanabe, Pfizer, Sanofi, Viatris, Consultant of: AbbVie, Asahi Kasei, Janssen, Pfizer, Grant/research support from: Chugai, Daiichi-Sankyo, Eli Lilly, Mitsubishi Tanabe, Ono, Takeda, Kotaro Matsumoto: None declared, Hiroshi Iijima: None declared, Seiji Nakamura: None declared, Yohei Ishizawa: None declared, Jun Inamo: None declared, Masaru Takeshita: None declared, Keiko Yoshimoto: None declared, Yuko Kaneko Speakers bureau: Chugai, Consultant of: Chugai, Grant/research support from: Chugai, Tsutomu Takeuchi Speakers bureau: Chugai, Consultant of: Chugai, Grant/research support from: Chugai.

Anxiety relaxation during MRI with a patient-friendly audiovisual system

INTRODUCTION

Many patients experience anxiety, not limited to claustrophobia, before magnetic resonance imaging (MRI) examination. We performed a non-randomized controlled trial to evaluate whether a patient-friendly audiovisual (AV) system in the MR scanner room reduces patient anxiety.

METHODS

We randomly selected 61 participants from outpatients who required brain MRI examination. Patients were informed that they could choose to undergo an MRI examination with a patient-friendly AV system (Ambient Experience, Philips Healthcare, Best, The Netherlands) or the standard system. To complete the MRI examination without affecting clinical practice, all patients who preferred the patient-friendly AV system were assigned to the preferring AV group. Patients who indicated that either system was acceptable were randomly assigned to the no preference but allocated AV group or control (using the standard system) groups. In both groups, state anxiety using the State-Trait Anxiety Inventory (STAI) was assessed before and after the MRI examination (A-State-before and A-State-after MRI, respectively). The changes in A-State-before and A-State-after MRI were categorized as follows: relieved high-state anxiety, no change in high-state anxiety, stable easiness, and intensified anxiety.

RESULTS

Among the 61 included patients, 19 were assigned to the preferring AV group, 20 to the no preference but allocated AV group, and 22 to the control group. There were no significant differences between the group. However, in patients with high-state anxiety before MRI, the preferring AV group and the no preference but allocated AV group, which used the patient-friendly AV system, relieved high-state anxiety by 63.6% (7 of 11 patients) and 81.8% (9 of 11 patients), respectively. In contrast, the control group using the standard system relieved high-level anxiety by only 42.9% (three out of seven patients).

CONCLUSION

The patient-friendly AV system may reduce anxiety in patients undergoing MRI examinations.

IMPLICATIONS FOR PRACTICE

The patient-friendly AV system may reduce anxiety in patients undergoing MRI examination by providing a more patient-centered MRI examination environment. These findings may help ameliorate negative perceptions associated with MRI examination.

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

Effects of uninterrupted dabigatran on the intensity of anticoagulation during atrial fibrillation ablation

Background

Uninterrupted dabigatran during atrial fibrillation (AF) ablation is now established as the standard therapy. However, there are few reports on the effects of uninterrupted dabigatran on the intensity of anticoagulation during AF ablation.

Methods

We retrospectively analyzed 247 consecutive patients who underwent AF ablation in our hospital from January 2017 to December 2018. Patients who took warfarin or uninterrupted direct oral anticoagulants (DOACs) except for dabigatran were excluded. 89 patients underwent ablation with uninterrupted dabigatran (uninterrupted group, male 71, mean age 59.6 ± 14.0) and 124 with interrupted DOACs (interrupted group, male 105, mean age 56.9 ± 12.9) during AF ablation. The initial ACT level, proportion of ACT levels of more than 300 s, and total amount of heparin were compared. Furthermore, the incidence of procedure complications was also evaluated.

Results

The initial ACT levels were significantly higher in the uninterrupted group, and the total number of ACTs of more than 300 s was significantly higher in the uninterrupted group (uninterrupted vs. interrupted; initial ACT level, 315.6 ± 59.8 vs. 264.5 ± 48.6, p < .001; total number of ACTs ≧300, n [%], 304/ 484 [62.8 %] vs. 372/745 [49.9%], p < .001). The total amount of heparin during procedure was significantly lower in the uninterrupted group (uninterrupted group vs. interrupted group; 12966 ± 4773 vs. 16371 ± 5212, p < .001). There was no significant difference in the incidence of complications between the two groups.

Conclusions

In the catheter ablation of AF, uninterrupted dabigatran would be useful to obtain a stable anticoagulation status during the entire procedure.

Colchicine protects against cartilage degeneration by inhibiting MMP13 expression via PLC-γ1 phosphorylation

OBJECTIVE

Low molecular weight compounds that reduce the expression of MMP13 at the mRNA level might serve as disease-modifying osteoarthritis (OA) drugs (DMOADs). The objective of this study was to identify a candidate DMOAD that targets MMP13 expression.

DESIGN

High-throughput screening was performed to identify compounds that suppress inflammatory cytokine-induced MMP13 expression. Ingenuity pathway analysis (IPA) using isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic analysis was conducted to identify signaling pathways related to cytokines. MMP13 expression in chondrocytes was evaluated through RT-qPCR and western blotting analyses. Additionally, 10-week-old mice were subjected to destabilization of the medial meniscus (DMM) surgery to induce OA and were sacrificed 12 weeks post-surgery for pathological examination. OA was evaluated using the OARSI scoring system.

RESULTS

Colchicine was identified as a DMOAD candidate as it inhibited inflammatory cytokine-induced MMP13 expression in vitro, and the colchicine-administered mice with DMM presented significantly lower OARSI scores (adjusted P: 0.0242, mean difference: 1.6, 95% confidence interval (CI) of difference: 0.1651-3.035) and significantly lower synovial membrane inflammation scores (adjusted P: 0.0243, mean difference: 0.6, 95% CI of difference: 0.06158-1.138) than mice with DMM. IPA further revealed that components of the Rho signaling pathways are regulated by cytokines and colchicine. IL-1β and TNF-α activate RAC1 and SRC signals, respectively, leading to the phosphorylation of PLC-γ1 and synergistic induction of MMP13 expression. Most notably, colchicine abrogates inflammatory cytokine-induced phosphorylation of PLC-γ1, leading to the induction of MMP13 expression.

CONCLUSIONS

Colchicine is a potential DMOAD candidate that inhibits MMP13 expression and consequent cartilage degradation by disrupting the SRC/RAC1-phospho-PLCγ1-Ca2+ signaling pathway.

Early and chronic phased local coagulative responses following bioresorbable-polymer drug-eluting stent implantation

Background

Neointimal maturation after bioresorbable-polymer (BP) drug-eluting stent (DES) implantation will not be complete in the absorption phase of the polymer. We have previously reported local persistent hypercoagulation after sirolimus-eluting stent (SES) implantation by measuring local plasma prothrombin fragment 1+2 (F1+2) levels. The aim of this study is to examine time-dependent local coagulative response after BP-DES implantation.

Methods

Sixty-four patients who were treated about ten months earlier with coronary angioplasty, with no evidence of restenosis, were studied [durable-polymer (DP)-DES {SES; Cypher®: 26pts and everolimus-eluting stent (EES); Xience®: 16pts} and BP-DES (BP-EES; Synergy®: 10pts and BP-SES; Ultimaster®: 12pts)]. We measured plasma levels of F1+2 sampled in coronary sinus (CS) and sinus of Valsalva (V) at the early (2±1 months) and chronic (10±2 months) phases. The transcardiac gradient (Δ) was defined as CS level minus V level.

Results

No significant differences were observed in the percent diameter stenosis between the DP- and BP- DES groups (11.5±15.5 vs 14.1±11.9%). The ΔF1+2 was significantly lower in the BP-DES group than in the DP-DES group at the chronic phase (7.5±16.1 vs 16.4±17.1pmol/l, p&lt;0.05). In the BP-DES group, the ΔF1+2 did not differ significantly between the early and chronic phases (7.0±14.1 vs 7.5±16.1pmol/l, NS).

Conclusion

Lower local coagulative response was observed at the chronic phase after BP-DES implantation compared to DP-DES implantation, and local hypercoagulation after BP-DES implantation was not observed at the early phase compared to the chronic phase. These findings might lead to the possibility of shorter dual antiplatelet therapy after BP-DES implantation.

Funding Acknowledgement

Type of funding sources: None.

Characteristics and optimal ablation settings of a novel, contact-force sensing and local impedance-enabled catheter in an ex vivo perfused swine ventricle model

BACKGROUND

Local impedance (LI) has emerged as a new technology that informs on electrical catheter-tissue coupling during radiofrequency (RF) ablation. Recently, IntellaNav StablePoint, a novel LI-enabled catheter that equips contact force (CF) sensing, has been introduced. Although StablePoint and its predecessor IntellaNav MiFi OI share the common technology that reports LI, distinct mechanics for LI sensing between the two products raise a concern that the LI-RF lesion formation relationship may differ.

METHODS

In an ex vivo swine cardiac tissue model, we investigated the initial level and range of a reduction in LI during a 60-s RF ablation and the resultant lesion characteristics at nine combinations of three energy power (30, 40, and 50 W) and CF (10, 30, and 50 g) steps. Correlations and interactions between CF, LI, wattage, and formed lesions were analyzed. Incidence of achieving LI drop plateau and that of a steam pop were also determined.

RESULTS

Positive correlations existed between CF and initial LI, CF and absolute/relative LI drop, CF and lesion volume, and LI drop and lesion volume. At the same LI drop, wattage-dependent gain in lesion volume was observed. Steam pops occurred in all CF steps and the prevalence was highest at 50 W. LI drop predicted a steam pop with a cutoff value at 89Ω.

CONCLUSION

In StablePoint, wattage crucially affects LI drop and lesion volume. Because 30 W ablation may by underpowered for intramural lesion formation and 50 W often resulted in a steam pop, 40 W appears to achieve the balance between the safety and efficacy.

Basic Study of Extensional Flow Mixing for the Dispersion of Carbon Nanotubes in Polypropylene by Using Capillary Extrusion

This study evaluated the mixing effect of simple uniaxial extensional flow for the dispersion of multiwalled carbon nanotubes (MWCNTs) into polypropylene (PP) as a nonpolar matrix. An only converging flow allowed for a high strain rate and was suitable for the compounding process. The extensional flow was characterized from the entrance pressure drop (ΔP0) at the converging section. Thus, in this study, capillary extrusion was employed to generate uniaxial extensional flow. Based on the hypothesis that the dispersion of nanofillers depends on the magnitude of flow-induced stress, ΔP0, which related to extensional stress, was measured directly during capillary extrusion by using an orifice die. The influences of the mass flow rate and the hole diameter in the orifice die, which affected ΔP0, on the extrusion of PP nanocomposites with an MWCNT loading of 1.0 wt.% were studied. The extruded samples were collected, and the dispersion state was evaluated based on the melt viscoelastic properties, volume resistivity, and morphological observations by optical microscopy (OM) and transmission electron microscopy (TEM). The agglomeration area of the MWCNTs decreased with higher ΔP0 (higher mass flow rate and smaller hole diameter), which increased the uniformity of the dispersion. Moreover, the influence of the length-to-diameter (L/D) ratio of the hole in the capillary die on the dispersion state of the MWCNTs was investigated. A higher L/D ratio of the capillary die did not improve the dispersion state, although shear and extensional stresses were provided.

Gender Differences in the Circadian and Seasonal Variations in Patients with Takotsubo Syndrome: A Multicenter Registry at Eight University Hospitals in East Japan

Objective The aim of this study was to clarify the circadian and seasonal variations in addition to identify sex-based differences in Japanese patients with Takotsubo syndrome (TTS). Methods The authors conducted a retrospective observational study to analyse the differences between the groups based on sex. Patients The patients were registered out of each institute registry of the acute coronary syndrome (ACS) which contains a total of 10,622 cases in eight academic hospitals in east Japan. Results Data for 344 consecutive TTS (73 male and 271 female) were extracted from each hospital registry. In-hospital mortality was higher in the male group than in the female group (18% vs. 7%; p=0.005). With regard to the circadian variations in all study patients, TTS events occurred most often in the afternoon and least often during the night. Moreover, the patterns of circadian variations in the female and male groups were the same as that of all study patients. TTS events occurred most frequently in the autumn and least often in the spring in the whole study cohort. Moreover, the seasonal variation in the female group showed the same pattern as that of the whole cohort. However, there were no significant seasonal differences in the incidence of TTS in the male group. Conclusion In a multicenter study in Japan, seasonal variation was observed in the female group but not in the male group. Circadian variation was observed in both groups. These results suggested that the pathogenesis and clinical features of TTS might therefore differ according to sex.

The optimal ablation setting for a local impedance guided catheter in an in vitro experimental model

BACKGROUND

The local impedance (LI) reflects the electrical catheter-tissue coupling and correlates with the local tissue temperature. However, there have been few clinical studies showing the recommended method for LI monitoring catheters. This study aimed to investigate the optimal ablation setting for this catheter in an in vitro experimental model.

METHODS

LI monitoring catheters were used in an excised swine heart experimental model. The tissue contact force (CF) was directly monitored from an external weight scale. Radiofrequency ablation was performed with a combination of various energy power settings (30, 40, and 50 W), and various CFs (10, 30, and 50 g) for 60 s. The correlation between the LI-related indexes, power, and CF with the lesion formation was statistically analyzed.

RESULTS

A positive correlation between the LI or lesion formation and CF was observed under all powers. Although the LI drop always correlated with the maximum lesion depth, lesion diameter, and lesion volume, the coefficient of the correlation value was lower under a high CF (lesion depth, diameter, and volume; 10 g, r = 0.8064, r = 0.8389, r = 0.8477; 30 g, r = 0.7590, r = 0.8063, r = 0.8060; 50 g r = 0.5555, r = 0.5701, and r = 0.5678, respectively). Steam pops occurred only under a 50 W ablation and the LI drop cutoff value for steam pops was 46 Ω.

CONCLUSION

The same LI drop did not always lead to the same lesion size when the CF differed. Monitoring the LI and not exceeding 46 Ω would be useful for a safe ablation.

Ultrahigh density atrio-ventricular dual-chamber mapping as a next generation tool for ablation of accessory pathways

INTRODUCTION

Detailed three-dimensional (3D) mapping has been useful for effective radiofrequency catheter ablation. The Rhythmia system can create atrio-ventricular dual-chamber mapping, which reveals the atrial and ventricular potentials all at once in the same map. The aim of this study was to investigate the utility of mapping the atrium and ventricle simultaneously with a high-density 3D mapping system for the ablation of accessory pathways (AP).

METHODS

From July 2015 to August 2020, 111 patients underwent ablation of APs. Dual-chamber maps were created in 50 patients (median age 15 [10-54], 32 male [64.0%]), while 61 patients underwent radiofrequency (RF) ablation with conventional single-chamber 3D maps. The background characteristics and procedural details were compared between the dual-chamber mapping group and the conventional single-chamber mapping group.

RESULTS

The number of RF applications (median [IQR]; 1.0 [1.0-3.0] vs. 3.0 [1.0-6.0], p = .0023), RF time (median [IQR], s; 9.2 [2.0-95.7] vs. 95.6 [4.1-248.7], p = .0107), and RF energy (median [IQR], J; 248.4 [58.7-3328.2] vs. 2867.6 [134.2-7728.4], p = .0115) were significantly lower in the dual-chamber group. The fluoroscopy time (median [IQR], min; 19.9 [14.2-26.1] vs. 26.5 [17.7-43.4], p = .0025) and fluoroscopy dose (median [IQR], mGy; 52.5 [31.3-146.0] vs. 119.0 [43.7-213.5], p = .0249) were also significantly lower in the dual-chamber than single-chamber mapping group.

CONCLUSION

The dual-chamber mapping was useful for ablating accessory pathways and reducing the number of RF applications, total RF energy, and radiation exposure as compared with traditional mapping techniques.

Transient Hyperintensity of the Infant Thyroid Gland on T1-Weighted MR Imaging: Correlation with Postnatal Age, Gestational Age, and Signal Intensity of the Pituitary Gland

BACKGROUND AND PURPOSE

The signal intensity of the thyroid in neonates is high on T1WI. It is affected by gestational and postnatal ages. However, the extent of the influence of these ages is unknown. This study investigated the relationship of signal intensities of the infant thyroid with postnatal and gestational ages and anterior pituitary using 3D gradient-echo T1WI.

MATERIALS AND METHODS

This retrospective study included 183 T1-weighted images from 181 infants. Using a multiple linear regression analysis, we evaluated the effects of postnatal and gestational ages on the thyroid-muscle signal intensity ratio. The relationship between the thyroid and anterior pituitary signal intensities on T1WI and the age of the infants was evaluated.

RESULTS

Multiple linear regression analysis showed that the thyroid signal intensity was affected negatively by postnatal age at examination and positively by gestational age at birth (P < .01 and P = .04, respectively). According to the standardized partial regression coefficients, the influence of postnatal age at examination was stronger than that of gestational age at birth (-0.72 and 0.13, respectively). The thyroid and anterior pituitary signal intensities reached constant values at 12 weeks' postnatal age, and the mean thyroid-anterior pituitary signal intensity ratios were almost 1 throughout the entire period.

CONCLUSIONS

The signal intensity of the infant thyroid on T1WI was more strongly influenced by the postnatal age at examination than the gestational age at birth, and it was almost equal to that of the anterior pituitary.

Impaired preload reserve is an important haemodynamic characteristics that discriminates between physiological ageing and overt heart failure with preserved ejection fraction

Funding Acknowledgements

Type of funding sources: None.

Background

 Ageing process per se is a major risk factor for heart failure (HF). In fact, the incidence of HF with preserved ejection fraction (HFpEF) dramatically increases with age. Although ageing plays a central role in the development of HFpEF, not all the elderly patients develop clinical HFpEF. Multiple abnormalities in the cardiovascular system have been proposed to contribute to the development of HFpEF. However, the pathophysiology that discriminates between physiological ageing and overt HFpEF is incompletely understood.

Purpose

 The purpose of this study was to assess the effects of ageing on the cardiac structures and haemodynamics. Moreover, we evaluated the determinant factor that discriminates between physiological ageing and overt HFpEF by non-invasive preload increasing manoeuvre using leg-positive pressure (LPP) stress echocardiography.

Methods

 A total of 91 subjects were prospectively recruited in this study: 22 patients with HFpEF and 69 healthy controls. Normal controls were further stratified into 3 age groups: young (n = 19, 20-40 years of age), middle-aged (N = 25, 40-65 years) and elderly (n = 25, &gt;65 years). All subjects underwent LPP stress with a continuous external pressure of 90 mmHg around both lower limbs using dedicated airbags (Fig.). 

Results

 The left ventricular mass index (LVMI; young, 68 ± 19 g/m²; middle-age, 70 ± 18 g/m²; elderly, 84 ± 21 g/m²) and also the relative wall thickness (RWT; young, 0.34 ± 0.09; middle-age, 0.41 ± 0.06; elderly 0.55 ± 0.10) increased with ageing, which was accelerated in HFpEF (LVMI: 111 ± 32 g/m², RWT; 0.63 ± 0.19, ANOVA P &lt; 0.001, respectively). Although baseline LV ejection fraction and cardiac output were quite comparable between groups, E/e’ ratio significantly increased with with ageing (ANOVA P &lt; 0.001, Fig.). During LPP stress, E/e’ ratio significantly increased in the middle-aged and elderly groups (from 8.8 ± 2.7 to 9.7 ± 3.3, and from 11.4 ± 2.4 to 13.0 ± 2.2, P &lt; 0.05, respectively), which was further deteriorated in HFpEF (from 16.8 ± 5.8 to 18.0 ± 7.6, P &lt; 0.05). On the other hand, stroke volume index (SVi) significantly increased in each healthy group during LPP stress (young; from 45 ± 10 to 50 ± 11 mL/m², middle-age; from 39 ± 7 to 44 ± 6 mL/m² and elderly; from 37 ± 7 to 43 ± 8 mL/m², all P &lt; 0.001), while SVi failed to increase in the HFpEF group (from 45 ± 13 to 45 ± 14 mL/m², P = 0.60). In a multivariate logistic regression analysis, LVMI (hazard ratio; HR 1.055, P &lt; 0.05), baseline E/e’ (HR 1.444; P &lt; 0.05), and ΔSVi (HR 0.755; P &lt; 0.05) during LPP stress were the independent parameters that characterised overt HFpEF.

Conclusions

 Striking parallels between structure-function alterations were observed in the physiological cardiovascular ageing process, which was further accelerated in patients with HFpEF. Not only structural remodeling and impaired diastolic function, but also impaired systolic reserve during preload stress is important haemodynamic feature that characterise the pathophysiology of HFpEF.

Abstract Figure.

Association between clinical risk factors and left ventricular function in patients with breast cancer following chemotherapy

Funding Acknowledgements

Type of funding sources: None.

Background

The sequential or concurrent use of two different types of agents such as anthracyclines and trastuzumab may increase myocardial injury and cancer therapeutics-related cardiac dysfunction (CTRCD), which is often the result of the combined detrimental effect of the two therapies for breast cancer patients. For risk stratification to detect the development of CTRCD, the current position paper from the European Society of Cardiology (ESC) lists several factors associated with risk of cardiotoxicity.

Purpose

Our purpose was to investigate the impact of baseline risk factors on left ventricular (LV) function in patients with preserved LV ejection fraction (LVEF) who have undergone chemotherapy for breast cancer.

Methods

We studied 86 breast cancer patients treated with anthracyclines, trastuzumab, or both. Mean age was 59 ± 13 years and LVEF was 67 ± 5%. In accordance with the current definition, CTRCD was defined as a decline in LVEF of &gt;10% to an absolute value of &lt;53% after chemotherapy. Based on the 2016 ESC position paper, clinical risk factors for CTRCD were defined as: (1) a cumulative total doxorubicin dose of ≥ 240mg/m², (2) age ≥ 65-year-old, (3) body mass index ≥ 30kg/m², (4) a previous history of radiation therapy to chest or mediastinum, (5) B-type natriuretic peptide ≥ 100pg/mL, (6) a previous history of cardiovascular disease, (7) atrial fibrillation, (8) hypertension, (9) diabetes mellitus, (10) current or ex-smoker.

Results

The relative decrease in LVEF after chemotherapy for patients with more than four risk factors was significantly greater than that for patients without (-9.3 ± 10.8% vs. -2.2 ± 10.2%; p = 0.02). However, this finding did not apply to patients with more than one, two or three risk factors. Patients with more than four risk factors also tended to show a higher prevalence of CTRCD than those without (14.3% vs. 2.8%, p = 0.12). Moreover, patients with more than four risk factors were more likely to have higher LV mass index (109.3 ± 29.0g/m² vs. 83.2 ± 21.0g/m², p &lt; 0.001), lower global longitudinal strain (18.4 ± 2.8% vs. 20.0 ± 2.6%, p = 0.06) and higher E/e’ (10.4 (8.9-13.0) vs. 9.0 (7.4-10.9), p = 0.06) compared to those without. 

Furthermore, receiver-operator characteristics curve analysis showed that an optimal cut off value of a cumulative total doxorubicin dose for developing LV dysfunction in patients with more than any of four risk factors was lower than that in those without (180 mg/m² vs. 280 mg/m²).

Conclusions

Association between clinical risk factors and LV dysfunction following chemotherapy became stronger with an increase in the number of risk factors in breast cancer patients, and was especially strong for patients treated with chemotherapy who had more than four risk factors. Our findings can thus be expected to have clinical implications for better management of patients with breast cancer referred for chemotherapy.

Abstract Figure.

impact of dapagliflozin on left ventricular diastolic function in diabetic patients with heart failure complicating cardiovascular risk factors

Funding Acknowledgements

Type of funding sources: None.

Background

Type 2 diabetes mellitus (T2DM) is a well-known risk factor for heart failure (HF), even in patients without a structural heart disease or a symptom of HF. Diabetes-related cardiomyopathy is presented as an left ventricular (LV) diastolic dysfunction, which, like cardiovascular disease, is a contributor of the development of HF in both patients with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF). Furthermore, comorbid factors other than T2DM also have been identified as high risk factors for of progression to HF. Dapagliflozin is a sodium glucose cotransporter type 2 (SGLT2) inhibitor, and represents a new class of anti-hyperglycemic agents for T2DM. A result from a recent large clinical trial showed that dapagliflozin reduced risk of worsening HF or death from cardiovascular causes for patients with HFrEF compared to those who received a placebo, regardless of the presence or absence of T2DM. However, the effect of SGLT2 inhibitors on LV diastolic function in T2DM patients with HF who had cardiovascular risk factors other than T2DM remains uncertain.

Purpose

Our purpose was to investigate the impact of dapagliflozin on LV diastolic function in T2DM patients with stable HF complicating cardiovascular risk factors.

Methods

We analyzed data from our previous prospective multicenter study, which investigate the effect of dapagliflozin on LV diastolic function of 53 T2DM patients with stable HF at five institutions in Japan. Patients who had been taking at least one antidiabetic drugs other than SGLT2 inhibitor started the administration of dapagliflozin. Cardiovascular risk factors other than T2DM was determined as age, gender, hypertension, dyslipidemia, history of cardiovascular events and overweight.

Results

E/e′ significantly decreased from 9.3 to 8.5 cm/s 6 months after administration of dapagliflozin (p = 0.020) as previously described. Multivariate logistic regression analysis showed that dyslipidemia was the only independent determinant of an improvement of E/e’ among cardiovascular risk factors. Furthermore, relative changes in E/e’ from baseline to 6 months after administration of dapagliflozin seen in HFpEF patients with dyslipidemia were significantly larger than those in HFpEF patients without dyslipidemia (-15.2% vs. 29.6%, p = 0.014), but such a difference was not observed in non-HFpEF patients. In addition, relative changes in high-density lipoprotein cholesterol (HDL-C) from baseline to 6 months after administration of dapagliflozin had significant correlation with those in E/e’ (r=-0.300, p = 0.038). However, such correlations were not observed in low-density lipoprotein cholesterol (LDL-C) and triglyceride (r = 0.05, p = 0.72 and r = 0.05, p = 0.73). Conclusion: Dapagliflozin was more beneficial effect on LV diastolic function for T2DM patients with stable HF, especially those with complicating dyslipidemia. Our findings may thus offer a new insight into the management of T2DM patients with HF.

Abstract Figure.

Preload stress echocardiography by using dynamic postural alteration can identify high risk patients with heart failure with reduced ejection fraction

Funding Acknowledgements

Type of funding sources: None.

Background

Haemodynamic assessment during stress testing is not commonly performed for patients with heart failure with reduced ejection fraction (HFrEF) due to its invasiveness, less feasibility, and safety concerns. Passive leg-lifting (PLL) manoeuvres have been introduced as a simple alternative for non-invasive preload stress testing; however, the haemodynamic load imposed on the cardiovascular system is unsatisfactory, which precludes the accurate assessment of the preload reserve for patients with HF.

Purpose

The purpose of this study was to assess the haemodynamic characteristics of patients with HFrEF in response to a preload stress during dynamic postural alterations by combining the semi-sitting position (SSP) and PLL. We also evaluated whether combined postural stress could be used for risk stratification for these patients.

Methods

For this study, 101 patients with HFrEF and 35 age- and sex-matched normal controls were prospectively recruited. At each postural position (i.e., baseline, SSP, and PLL), all standard echocardiographic and Doppler variables were obtained. Adverse cardiac events were prespecified as the combined endpoints of death from or hospitalisation for deteriorated HF, or sudden cardiac death. Clinical follow-up was conducted for a median of 7 months.

Results

During PLL stress, the stroke volume index (SVi) significantly increased in both controls (from 40 ± 6 to 43 ± 6 mL/m², P = 0.03) and HFrEF patients (from 31 ± 9 to 34 ± 10 mL/m², P = 0.03). Conversely, during SSP stress, the SVi significantly decreased for both controls (from 40 ± 6 to 37 ± 6 mL/m², P = 0.03) and HFrEF patients (31 ± 9 to 28 ± 8 mL/m², P = 0.03). During the follow-up period, 16 patients developed cardiac events. In patients without events, the Frank-Starling mechanism was well preserved (Fig. A). Namely, the SVi significantly increased from 31 ± 9 to 35 ± 10 mL/m² (P = 0.02) during PLL stress, while the SVi significantly decreased from 31 ± 8 to 28 ± 8 mL/m² (P = 0.02) during SSP stress. In contrast, for patients with cardiac events, the SVi did not change during postural alterations (n.s), which indicated that the failing heart operates on the flat portion of the Frank-Starling curve (Fig. A). When patients were divided into three equal sub-groups based on the total difference in the SVi during dynamic postural stress, patients with impaired preload reserve (third trimester, ΔSVi ≤ 3.0 mL/m²) showed significantly worse event-free survival than the other two sub-groups (Fig. B; P &lt; 0.001). In a Cox proportional-hazard analysis, baseline LVEF (hazard ratio 0.93; P = 0.04), and ΔSVi during postural stress (hazard ratio 0.76; P = 0.004) were predictors of future cardiac events.

Conclusions

The combined assessment of dynamic postural stress during PLL and SPP is a simple, time-saving, and easy-to-use clinical tool for the assessment of preload reserve for patients with HFrEF. Moreover, postural stress echocardiography proved to contribute to the risk stratification for these patients.

Abstract Figure.

Cardiac resynchronization therapy improves left atrial reservoir function through resynchronization of the left atrium in patients with heart failure

Funding Acknowledgements

Type of funding sources: None.

Background

The structural remodeling of the left atrium (LA) has been proposed as an important determinant of adverse outcomes in patients with heart failure (HF). However, little is known about the potential impact of LA mechanical dyssynchrony on its reservoir function and the prognosis of patients with HF. In addition, it has not been fully investigated whether cardiac resynchronization therapy (CRT) is also beneficial to LA function.

Purposes

The purposes of this study were to test whether left ventricular (LV) dyssynchrony may negatively affect LA synchronicity and reservoir function, and to assess whether residual LA dyssynchrony after CRT affects the prognosis in patients with HF with reduced ejection fraction (HFrEF).

Methods

This study included total of 90 subjects: 40 HFrEF with a wide-QRS complex (≧130 ms), 28 HFrEF with a narrow-QRS, and 22 age- and sex-matched normal controls. LA global longitudinal strain (LA-GLS) and LA dyssynchrony were quantified using speckle-tracking strain analysis. LA dyssynchrony was defined as the maximal difference of time-to-peak strain (LA time-diff). All wide-QRS HFrEF received CRT, and event-free survival was tracked for 24 months.

Results

At baseline, HFrEF patients showed significant LA remodeling coupled with the reduced LA reservoir function, as evidenced by larger LA volume index (LAVi: 46 ± 16 vs. 30 ± 14 mL/m², P &lt; 0.01) and smaller LA-GLS (13.0 ± 4.8 vs. 30.6 ± 10.7%, P &lt; 0.01). Of note was that, not only LV dyssynchrony (381 ± 178 vs. 177 ± 62 ms, P &lt; 0.01) but also LA dyssynchrony (298 ± 136 vs. 186 ± 78 ms, P &lt; 0.01) were significantly larger in patients with HFrEF compared to normal subjects and this applied even more to patients with a wide-QRS complex. All patients with a wide-QRS complex underwent CRT, and only responders exhibited the significant decrease in LA time-diff (from 338 ± 123 to 245 ± 141 ms, P &lt; 0.05) and increase in LA-GLS (from 11.9 ± 4.7 to 19.6 ± 10.1%, P &lt; 0.05) in parallel with the reduction in LAVi (from 48 ± 17 to 37 ± 18 mL/m², P &lt; 0.05) at 6 months after CRT. Receiver operating characteristic curve analysis identified the optimal cut-off value of LA time-diff at 6 months after CRT as 202 ms (P &lt; 0.05) and that of LA-GLS as 14.6% (P &lt; 0.05) for predicting adverse cardiac events. The patients whose LA time-diff reduced &lt;202 ms after CRT showed significantly favorable event-free survival than the others. Similarly, the patients whose LA-GLS improved &gt;14.6% after CRT exhibited significantly favorable event-free survival than the others (P &lt; 0.05, respectively). Of note was that, when the patients were restricted to CRT responders only, those who showed LA time-diff less than 202 ms at 6 months after CRT almost never experienced cardiac events (P &lt; 0.05).

Conclusions

The improved LV coordination by CRT also resulted in resynchronization of discoordinated LA wall motion and a consecutive improvement of LA reservoir function, which ultimately lead to the favorable outcome for HFrEF patients with wide-QRS complex.

Abstract Figure.

preoperative right ventricular overwork is a major determinant of residual pulmonary arterial hypertension in patients with repaired arterial septal defect

Funding Acknowledgements

Type of funding sources: None.

Background

The haemodynamic effect of atrial septal defect (ASD) is a chronic volume overload of the right heart and pulmonary vasculature. Pulmonary overcirculation is generally compensated for by the right ventricular (RV) and pulmonary arterial (PA) reserve. However, in a subset of patients, prolonged pulmonary overcirculation insidiously induces obstructive pulmonary vasculopathy, which results in postoperative residual pulmonary arterial hypertension (PAH) after ASD closure. Postoperative PAH is a major concern because it is closely associated with poor outcomes and impaired quality of life. However, to date, no clinically robust predictors of postoperative residual PAH have been clearly identified.

Purpose

This study sought to assess the haemodynamic characteristics of ASD patients in terms of mechano-energetic parameters and to identify the predictors of postoperative residual PAH in these patients.

Methods

A total of 120 ASD patients (age: 58 ± 17 years) and 46 normal controls were recruited. As previously reported, the simplified RV contraction pressure index (sRVCPI) was calculated as an index of RV external work by multiplying the tricuspid annular plane systolic excursion (TAPSE) by the pressure gradient between the RV and right atrium. RV- PA coupling was evaluated using TAPSE divided by PA systolic pressure as an index of the RV length-force relationship. These parameters were measured both at baseline and 6 months after ASD closure.

Results

As expected, baseline sRVCPI was significantly greater in patients with ASD than in controls (775 ± 298 vs. 335 ± 180 mm Hg • mm, P &lt; 0.01), which indicated significant "RV overwork". As a result, RV-PA coupling in ASD patients was significantly impaired compared to that in controls (0.9 ± 0.8 vs. 3.5 ± 1.7 mm/mm Hg, P &lt; 0.01). All 120 ASD patients underwent transcatheter or surgical shunt closure; 15 of them had residual PAH after closure. After 6 months, RV-PA coupling index significantly improved in patients without residual PAH, from 0.96 ± 0.81 to 1.27 ± 1.24 mm/mm Hg (P = 0.02). Furthermore, RV load was markedly reduced, with sRVCPI falling from 691 ± 258 to 434 ± 217 mm Hg • mm, P &lt; 0.01). However, in patients with residual PAH, RV-PA coupling index deteriorated from 0.64 ± 0.23 to 0.53 ± 0.12 mm/mm Hg (P &lt; 0.01). As a result, RV overload was not significantly relieved (sRVCPI; from 971 ± 382 to 783 ± 166 mm Hg • mm, P = 0.22). In a multivariate analysis, baseline pulmonary vascular resistance (hazard ratio 1.009; P &lt; 0.01) and preoperative sRVPCI (hazard ratio 1.003; P &lt; 0.01) revealed to be independent predictors of residual PAH.

Conclusion

In terms of mechano-energetic function, preoperative "RV overwork" can be used as a robust predictor of an impaired RV-PA relationship in ASD patients. Moreover, periodic assessment of sRVPCI may contribute to the better management for patients with unrepaired ASD.

Abstract Figure.

Antegrade slow pathway mapping of typical atrioventricular nodal reentrant tachycardia based on direct slow pathway capture

BACKGROUND

Radiofrequency (RF) ablation of typical atrioventricular nodal reentrant tachycardia (tAVNRT) is performed without revealing out the location of antegrade slow pathway (ASp). In this study, we studied a new electrophysiological method of identifying the site of ASp.

METHODS

This study included 19 patients. Repeated series of very high-output single extrastimulations (VhoSESts) were delivered at the anatomical slow pathway region during tAVNRT. Tachycardia cycle length (TCL), coupling interval (CI), and return cycle (RC) were measured and the prematurity of VhoSESts [ΔPM (= TCL - CI)] and the prolongation of RCs [ΔPL (= RC - TCL)] were calculated. Pacing sites were classified into two categories: (i) ASp capture sites [DSPC(+) sites], where two different RCs were shown, and ASp non-capture sites [DSPC(-) sites], where only one RC was shown. RF ablation was performed at DSPC(+) sites and/or sites with catheter-induced mechanical trauma (CIMT) to ASp.

RESULTS

DSPC(+) sites were shown in 13 patients (68%). RF ablation was successful in all patients without any degree of atrioventricular block nor recurrence. Total number of RF applications was 1.8 ± 1.1. Minimal distance between successful ablation sites and DSPC(+)/CIMT sites and His bundle (HB) electrogram recording sites was 1.9 ± 0.8 mm and 19.8 ± 6.1 mm, respectively. ΔPL of more than 92.5 ms, ΔPL/TCL of more than 0.286, and ΔPL/ΔPM of more than 1.565 could identify ASp with sensitivity of 100%, 91.1%, and 88.9% and specificity of 92.9%, 97.0%, and 97.6%, respectively.

CONCLUSIONS

Sites with ASp capture and CIMT were close to successful ablation sites and could be useful indicators of tAVNRT ablation.

Transvenous lead performance of implantable cardioverter-defibrillators and pacemakers

BACKGROUND

After the reports of recalled leads, several technological improvements have been introduced and the durability of implantable cardioverter defibrillator (ICD) leads has improved. The incidence of lead failures is now less than in the previous studies. However, there are few reports that have shown the long-term durability of ICD leads as compared to pacemaker (PM) leads. This study analyzed the medium to long-term performance of transvenous ICD leads as compared to PM leads.

METHODS

We retrospectively studied 1227 cases from April 2007 to December 2017 who underwent an initial transvenous ICD or PM implantation. The number of lead failures and patient background characteristics were analyzed.

RESULTS

During a median 3-3.5 years follow up period, 1 (0.3%) ICD lead and 18 (2.4%) PM leads failed. The incidence of lead failures was significantly higher in the PM group than ICD group (p = .019). Males were associated with a higher incidence of lead failures in the PM group.

CONCLUSION

Since the era of recalled ICD leads, the durability of ICD leads has remarkably improved and the incidence of lead failures with non-recalled ICD leads has been less than that for PM leads.

An analysis of osteoporosis in patients with hereditary multiple exostoses

We analyzed osteoporosis in 20 HME patients. According to the T-score of BMD, 30% and 67.5% of the patients fell in the range of osteopenia in the lumbar spine and femoral neck. Our results indicate HME patients have low bone mass. They do not have abnormal bone metabolism.

INTRODUCTION

There are few reports of osteoporosis in hereditary multiple exostoses (HME) patients. Therefore, the purpose of this study was to analyze osteoporosis in HME patients.

METHODS

This retrospective cohort study included 20 patients diagnosed with HME. Patients underwent bone mineral density (BMD) measurement of the lumbar spine (n = 20) and femoral neck (n = 40). Bone metabolic parameters, including serum osteocalcin and urinary cross-linked N-telopeptide of type 1 collagen (NTx), were analyzed in all subjects. EXT1 and EXT2 genes were sequenced using genomic DNA. We also examined the correlation between genotype and BMD Z-score and T-score.

RESULTS

The mean BMD values of the lumbar spine were 1.085 ± 0.116 g/cm² (n = 11) in male and 1.108 ± 0.088 g/cm² (n = 9) in female. The mean BMD values of the femoral neck area were 0.759 ± 0.125 g/cm² (n = 22) in male and 0.749 ± 0.115 g/cm² (n = 18) in female. Z-score of most HME patients show < 0, indicating that these patients tend to have low bone mass compared with the age-matched population. According to the T-score of BMD, 30% (6 of 20) and 67.5% (27 of 40) of the patients fell in the range of osteopenia in the lumbar spine and femoral neck areas, respectively. Serum osteocalcin and urinary NTx were in the normal range in most patients. There was no significant correlation between genotypes and Z-score.

CONCLUSION

HME patients have low bone mass, especially in the femoral neck area. They do not have abnormal bone metabolism, and there was no correlation between genotypes and Z-score.

Caprylic acid enhances hydroxyhexylitaconic acid production in Aspergillus niger S17-5

AIM

Aspergillus niger S17-5 produces two alkylitaconic acids, 9-hydroxyhexylitaconic acid (9-HHIA) and 10-hydroxyhexylitaconic acid (10-HHIA), which have cytotoxic and polymer building block properties. In this study, we characterized the production of 9-HHIA and 10-HHIA by addition of their expected precursor, caprylic acid, to a culture of A. niger S17-5, and demonstrated batch fermentation of 9-HHIA and 10-HHIA in a jar fermenter with DO-stat.

METHODS AND RESULTS

Production titres of 9-HHIA and 10-HHIA from 3% glucose in a flask after 25 days cultivation were 0·35 and 1·01 g l^-1 respectively. Addition of 0·22 g l^-1 of caprylic acid to a suspension of resting cells of A. niger S17-5 led to 32% enhancement of total 9-HHIA and 10-HHIA production compared to no addition. No enhancement of the production of 9-HHIA or 10-HHIA by the addition of oxaloacetic acid was observed. Addition of caprylic acid to the culture at mid-growth phase was more suitable for 9-HHIA and 10-HHIA production due to less cell growth inhibition by caprylic acid. DO-stat batch fermentation with 3% glucose and 14·4 g l^-1 of caprylic acid in a 1·5 l jar fermenter resulted in the production titres of 9-HHIA and 10-HHIA being 0·48 and 1·54 g l^-1 respectively after 10 days of cultivation.

CONCLUSIONS

Addition of caprylic acid to the culture of A. niger S17-5 enhances 9-HHIA and 10-HHIA production.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results suggest that 9-HHIA and 10-HHIA are synthesized with octanoyl-CoA derived from caprylic acid, and that the supply of octanoyl-CoA is a rate-limiting step in 9-HHIA and 10-HHIA production. To the best of our knowledge, this is the first report regarding the fermentation of naturally occurring itaconic acid derivatives in a jar fermenter.

Toll-like receptor 9 is a novel therapeutic target to prevent atrial fibrillation

Background

Atrial fibrillation (AF) is the most common type of arrhythmia seen in clinical practice. Recent studies suggest that inflammation contributes to the pathogenesis of AF. On the other hand, several evidence suggests that toll-like receptor (TLR) 9 recognizes bacterial DNA, activating innate immunity, whereas it also provokes inflammation in response to fragmented DNA released from mammalian cells. Recently, we have reported that TLR 9 plays a pivotal role in the development of vascular inflammation and atherogenesis through proinflammatory activation of macrophages.

Purpose

This study aimed to assess whether TLR9 contributes to the AF arrhythmogenesis.

Methods

TLR9 deficient (TLR9−/−) and wild-type mice were infused with angiotensin II (Ang II) or vehicle via an osmotic minipump for 4 weeks. Blood pressure and body weight were measured serially. Then, we examined AF inducibility by intracardiac electrophysiological study and the inflammation-induced atrial remodeling by biochemical analysis after 4 weeks of Ang II infusion.

Results

There was no significant difference in blood pressure and pulse rate between TLR9−/− and wild-type mice both before and after Ang II infusion. Ang II-treated TLR9−/− mice showed lower incidence of AF compared with wild-type mice treated with Ang II. Genetic deletion of TLR9 significantly reduced the interstitial fibrosis in atrium of Ang II-treated mice. TLR9−/− mice also showed less mRNA expressions of inflammatory and fibrosis-related biomarkers (TNF-α, interleukin-6, TGF-β, collagen-1, collagen-3) in atrium compared with wild-type mice.

Conclusions

TLR9 might contribute to the AF arrhythmogenesis associated with atrial inflammation. TLR9 might serve as a potential therapeutic target for AF.

Funding Acknowledgement

Type of funding source: None

Association between clinical risk factors and left ventricular function in patients with breast cancer following chemotherapy

Background

The sequential or concurrent use of two different types of agents such as anthracyclines and trastuzumab may increase myocardial injury and cancer therapeutics-related cardiac dysfunction (CTRCD), which is often the result of the combined detrimental effect of the two therapies for breast cancer patients. For risk stratification to detect the development of CTRCD, the current position paper from the European Society of Cardiology (ESC) lists several factors associated with risk of cardiotoxicity following treatment with chemotherapy. However, the association between clinical risk factors and left ventricular (LV) function in breast cancer patients is currently unclear.

Purpose

Our purpose was to investigate the impact of baseline risk factors on LV function in patients with preserved LV ejection fraction (LVEF) who have undergone anthracycline or trastuzumab chemotherapy for breast cancer.

Methods

We studied 86 breast cancer patients treated with anthracyclines, trastuzumab, or both. Mean age was 59±13 years and LVEF was 67±5%. In accordance with the current definition, CTRCD was defined as a decline in LVEF of &gt;10% to an absolute value of &lt;53% after chemotherapy. Based on the 2016 ESC position paper, clinical risk factors for CTRCD were defined as: (1) a cumulative total doxorubicin dose of ≥240 mg/m2, (2) age ≥65-year-old, (3) body mass index ≥30 kg/m2, (4) a previous history of radiation therapy to chest or mediastinum, (5) B-type natriuretic peptide ≥100pg/mL, (6) a previous history of cardiovascular disease, (7) atrial fibrillation, (8) hypertension, (9) diabetes mellitus, (10) current or ex-smoker.

Results

The relative decrease in LVEF after chemotherapy for patients with more than four risk factors was significantly greater than that for patients without (−9.3±10.8% vs. −2.2±10.2%; p=0.02). However, this finding did not apply to patients with more than one, two or three risk factors. Patients with more than four risk factors also tended to show a higher prevalence of CTRCD than those without (14.3% vs. 2.8%, p=0.12). Moreover, patients with more than four risk factors were more likely to have higher LV mass index (109.3±29.0 g/m2 vs. 83.2±21.0g /m2, p&lt;0.001), lower global longitudinal strain (18.4±2.8% vs. 20.0±2.6%, p=0.06) and higher E/e' (10.4 (8.9–13.0) vs. 9.0 (7.4–10.9), p=0.06) compared to those without.

Conclusions

Association between clinical risk factors and LV dysfunction following chemotherapy became stronger with an increase in the number of risk factors in breast cancer patients, and was especially strong for patients treated with chemotherapy who had more than four risk factors. Our findings can thus be expected to have clinical implications for better management of patients with breast cancer referred for chemotherapy.

Funding Acknowledgement

Type of funding source: None

Consideration of non-valvular atrial fibrillation with left atrial appendage thrombus formation despite under appropriate oral anticoagulation therapy

Background

Atrial fibrillation (AF) is the most frequently sustained cardiac arrhythmia, with a prevalence of about 2–3% in the general population. In accordance with CHADS2 or CHA2DS2-VASc score, appropriate oral anticoagulation therapy such as warfarin or direct oral anticoagulants (DOAC) significantly reduced the risk of thromboembolic events. However, left atrial (LA) thrombus can be detected in the LA appendage (LAA) in AF patients despite appropriate oral anticoagulation therapy.

Purpose

Our purpose was to investigate the associated factors of LAA thrombus formation in non-valvular atrial fibrillation (NVAF) patients despite under appropriate oral anticoagulation therapy.

Methods

We retrospectively studied consecutive 286 NVAF patients for scheduled catheter ablation or electrical cardioversion for AF in our institution between February 2017 and September 2019. Mean age was 67.1±9.4 years, 79 patients (29.5%) were female, and 140 (52.2%) were paroxysmal AF. All patients underwent transthoracic and transesophageal echocardiography before catheter ablation or electrical cardioversion. All patients received appropriate oral anticoagulation therapy including warfarin or DOAC for at least 3 weeks prior to transesophageal echocardiography based on the current guidelines. LAA thrombus was defined as an echodense intracavitary mass distinct from the underlying endocardium and not caused by pectinate muscles by at least three senior echocardiologists.

Results

Of 286 NVAF patients with under appropriate oral anticoagulation therapy, LAA thrombus was observed in 9 patients (3.3%). Univariate logistic regression analysis showed that age, paroxysmal AF, CHADS2 score ≥3, left ventricular end-diastolic volume index (LVEDVI), left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), LA volume index (LAVI), mitral inflow E and mitral e' annular velocities ratio (E/e'), and LAA flow were associated with LAA thrombus formation. It was noteworthy that multivariate logistic regression analysis showed that LAA flow was independent predictor of LAA thrombus (OR: 0.72, 95% CI: 0.59–0.89, p&lt;0.005) as well as LVEF. Furthermore, receiver operating characteristic (ROC) curve analysis identified the optimal cutoff value of LAA flow for predicting LAA thrombus as ≤15cm/s, with a sensitivity of 88%, specificity of 93%, and area under the curve (AUC) of 0.95.

Conclusions

LAA flow was strongly associated with LAA thrombus formation even in NVAF patients with appropriate oral anticoagulation therapy. According to our findings, further strengthen of oral anticoagulation therapy or percutaneous transcatheter closure of the LAA may be considered in NVAF patients with appropriate oral anticoagulation therapy but low LAA flow, especially &lt;15cm/s.

Funding Acknowledgement

Type of funding source: None

Frequency of cardiac arrhythmias in older adults: findings from the subclinical atrial fibrillation and risk of ischemic stroke (SAFARIS) study

Background

Prolonged monitoring of cardiac rhythm has been used in patients with symptomatic arrhythmias and to assess for atrial fibrillation (AF) after cryptogenic stroke, but not in the general population and especially in older adults.

Purpose

To evaluate the frequency of arrhythmias in a community-based cohort of older adults through 14-days continuous cardiac monitoring using a patch-based device.

Methods

Cardiac rhythm was analyzed in 533 participants free of AF and congestive heart failure (CHF) from the tri-ethnic (white, black, Hispanic) Subclinical Atrial Fibrillation and Risk of Ischemic Stroke (SAFARIS) study. AF, supraventricular tachycardia (SVT, defined as 4 beats or more), premature atrial (PACs) and ventricular (PVCs) contractions, ventricular tachycardia (VT, defined as 4 beats or more), sinus pauses (SP) and atrio-ventricular blocks (AVB) were analyzed. Gender, age and race-ethnic differences were examined.

Results

Mean age was 77.2±6.8 years (198 men, 335 women). Recording duration was over 10 days in 91%, and over 13 days in 84%. AF was present in 10 participants (1.9%), atrial flutter in 1 (0.2%). Other arrhythmias are reported in the Table. SP (1.9%) and high-degree AVB (Mobitz II: 0.6%; 3rd degree: 0.9%) were rare. No significant race-ethnic differences were observed.

Conclusion

In older adults without history of stroke or CHF, prolonged rhythm monitoring revealed moderate frequency of AF, but higher than expected frequencies of AF-predisposing conditions such as SVT and frequent PACs. VT episodes were relatively frequent, whereas SP and AVB were less frequent than commonly believed. Most arrhythmias were more frequent in the oldest; ventricular arrhythmias were more common in men than in women.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): NINDS R01 NS083874

Positive effect of dapagliflozin on left ventricular longitudinal function for type 2 diabetic mellitus patients with chronic heart failure

Background

Type 2 diabetes mellitus (T2DM) has come to be considered an independent predictor of mortality, and also a contributor to the development of heart failure (HF) with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF). Left ventricular (LV) longitudinal myocardial dysfunction as assessed in terms of lower global longitudinal strain (GLS), has been identified even in T2DM patients with preserved LV ejection fraction (LVEF), and should be considered the first marker of a preclinical form of DM-related cardiac dysfunction, leading to HFpEF. Sodium glucose cotransporter type 2 (SGLT2) inhibitors represent a new class of anti-hyperglycemic agents for T2DM, but the effect of SGLT2 inhibitors on LV longitudinal myocardial function in T2DM patients with HF remains uncertain. To examine this effect, as well as the association of LV longitudinal myocardial function with LV diastolic function after administration of SGLT2 inhibitor in T2DM patients with stable HF, we analyzed data from our previous prospective multicenter study, in which we investigated the effect of SGLT2 inhibitor on LV diastolic functional parameters of T2DM patients with stable HF at five institutions in Japan.

Methods

Our previous trial was a prospective multicenter study of 58 T2DM patients with stable HF at five institutions in Japan. Patients who had been taking at least one antidiabetic drugs other than SGLT2 inhibitors started the administration of 5 mg/day of dapagliflozin. Echocardiography was performed at baseline and 6 months after administration of dapagliflozin. LV diastolic function was defined as the ratio of mitral inflow E to mitral e' annular velocities (E/e'). LV longitudinal myocardial function was assessed as GLS based on the current guidelines.

Results

E/e' significantly decreased from 9.3 to 8.5 cm/s 6 months after administration of dapagliflozin (p=0.020) as previously described, while GLS showed significant improvement from 15.5±3.5% to 16.9±4.1% (p&lt;0.01) 6 months after administration of dapagliflozin. Furthermore, improvement of GLS in HFpEF patients was more significant from 17.0±1.9% to 18.7±2.0% (p&lt;0.001), compared to that in HFrEF patients from 11.3±3.8% to 11.8±4.6% (p=0.13). It was noteworthy that multiple regression analysis showed that the change in GLS after administration of dapagliflozin was the only independent determinant parameter for the change in E/e' after administration of dapagliflozin.

Conclusion

Dapagliflozin was found to be associated with improvement of LV longitudinal myocardial function, which led to further improvement of LV diastolic function of T2DM patients with stable HF. GLS-guided management may thus lead to improved management of T2DM patients with stable HF.

Representative case

Funding Acknowledgement

Type of funding source: None

Heparan sulfate deficiency leads to hypertrophic chondrocytes by increasing bone morphogenetic protein signaling

OBJECTIVE

Exostosin-1 (EXT1) and EXT2 are the major genetic etiologies of multiple hereditary exostoses and are essential for heparan sulfate (HS) biosynthesis. Previous studies investigating HS in several mouse models of multiple hereditary exostoses have reported that aberrant bone morphogenetic protein (BMP) signaling promotes osteochondroma formation in Ext1-deficient mice. This study examined the mechanism underlying the effects of HS deficiency on BMP/Smad signaling in articular cartilage in a cartilage-specific Ext^-/- mouse model.

METHOD

We generated mice with a conditional Ext1 knockout in cartilage tissue (Ext1-cKO mice) using Prg4-Cre transgenic mice. Structural cartilage alterations were histologically evaluated and phospho-Smad1/5/9 (pSmad1/5/9) expression in mouse chondrocytes was analyzed. The effect of pharmacological intervention of BMP signaling using a specific inhibitor was assessed in the articular cartilage of Ext1-cKO mice.

RESULTS

Hypertrophic chondrocytes were significantly more abundant (P = 0.021) and cartilage thickness was greater in Ext1-cKO mice at 3 months postnatal than in control littermates (P = 0.036 for femur; and P < 0.001 for tibia). However, osteoarthritis did not spontaneously occur before the 1-year follow-up. matrix metalloproteinase (MMP)-13 and adamalysin-like metalloproteinases with thrombospondin motifs(ADAMTS)-5 were upregulated in hypertrophic chondrocytes of transgenic mice. Immunostaining and western blotting revealed that pSmad1/5/9-positive chondrocytes were more abundant in the articular cartilage of Ext1-cKO mice than in control littermates. Furthermore, the BMP inhibitor significantly decreased the number of hypertrophic chondrocytes in Ext1-cKO mice (P = 0.007).

CONCLUSIONS

HS deficiency in articular chondrocytes causes chondrocyte hypertrophy, wherein upregulated BMP/Smad signaling partially contributes to this phenotype. HS might play an important role in maintaining the cartilaginous matrix by regulating BMP signaling.