Radiation Dose-escalated Chemoradiotherapy Using Simultaneous Integrated Boost Intensity-Modulated Radiotherapy for Locally Advanced Unresectable Thoracic Oesophageal Squamous Cell Carcinoma: A Single-institution Phase I Study

AIMS

About 80% of cases of locally advanced unresectable thoracic oesophageal squamous cell carcinoma recur within the irradiation fields after chemoradiotherapy. Radiation dose escalation using advanced radiotherapy techniques is expected to improve clinical outcomes by reducing local and regional recurrence. The current study aimed to determine the recommended escalated radiation dose for these patients.

MATERIALS AND METHODS

Patients with locally advanced unresectable thoracic oesophageal squamous cell carcinoma with good performance status underwent chemoradiotherapy using simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) with elective nodal irradiation. SIB-IMRT was delivered in five fractions per week. The radiation dose to the unresectable gross tumour was escalated from 66 Gy to a planned maximum dose of 72 Gy in 3 Gy increments in a standard 3 + 3 design. The doses to the resectable component, superficial tumours and elective nodal regions were fixed as 60, 51 and 48 Gy, respectively. Cisplatin and 5-fluorouracil were concurrently administered. Dose-limiting toxicity (DLT) was defined as acute grade 3 oesophagitis, grade 2 pneumonitis, grade 2 cardiac toxicity and a failure to complete planned radiotherapy within 60 days. Locoregional control and overall survival were estimated using the Kaplan-Meier method. Nine patients were enrolled.

RESULTS

DLTs occurred in one of six and two of three patients at doses of 66 and 69 Gy, respectively. All DLTs were grade 3 oesophagitis. The recommended dose was determined as 66 Gy delivered in 30 fractions based on the predefined criteria. With a median follow-up period of 23 months, the 1-year locoregional control and overall survival rates were 67 (95% confidence interval = 19-90) and 78% (95% confidence interval = 36-94), respectively.

CONCLUSION

The recommended radiation dose in chemoradiotherapy using SIB-IMRT with elective nodal irradiation was 66 Gy delivered in 30 fractions.

DEVELOPMENT OF A JAPANESE INFANT HEAD-CHEST PHANTOM AND INVESTIGATION OF THE CURRENT STATUS OF INFANT HEAD CT EXAMINATIONS IN JAPAN

The aim of this study was to develop a head-chest phantom that could mimic the physique of a Japanese 0.5-year-old child and to investigate the current status of exposure dose in infant head computed tomography examinations in Japan. The phantom was produced by machine processing, and radiophotoluminescence glass dosemeters were installed in the phantom for dose measurement. Organ doses were measured for seven different head scan protocols routinely used in three hospitals. In this study, the average dose of the brain and lens within the scan region was equivalent to that measured using infant phantoms in previous studies. In contrast, the doses of both salivary glands and thyroid glands adjacent to the scan region were 1.4-1.8 times higher than those in previous studies. Expansion of the scan area accompanied by a transition of the scan mode from non-helical to helical may have resulted in the differences in organ doses.

Electrochemical reduction of CO2 using Germanium-Sulfide-Indium amorphous glass structures

The research in electrochemical reduction of CO₂ is shifting towards the discovery of new and novel materials. This study shows a new class of material, that of Ge-S-In chalcogenide glass, to be active for reduction of CO₂ in aqueous solutions. Experiments were conducted with bulk and particle form of the material, yielding different product for each structural form. Faradaic efficiency of upto 15% was observed in bulk form for CO production while formic acid with up to 26.1 % faradaic efficiency was measured in powder form. Chalcogenide studies have focused primarily on the photoelectrochemical reduction however these results provide a strong merit for introducing metal in chalcogenide glass structures for electrochemical reduction of CO₂. The activity for CO₂ reduction and the change in product selectivity reflects that further efforts to improve the glass structures can be undertaken in order to increase the faradaic efficiency and selectivity of the products.

P18 The utility and validity of intracoronary administration of nicorandil alone for the measurement of fractional flow reserve in patients with intermediate coronary stenosis

Backgrand

Recently, intracoronary nicorandil (ICN) administration in addition to intravenous adenosine 5"-triphosphate (IVATP) is generally used to achieve maximal hyperemia for evaluating fractional flow reserve (FFR). This study investigated the usefulness and safety of ICN alone compared with  IVATP and ICN during IVATP for the achievement of maximal hyperemia in patients with suspected angina pectoris. 

Methods

Two-hundred-ten angiographically intermediate lesions in two-hundred-seven patients who underwent FFR assessments were enrolled. FFR was measured after ICN (2mg/5seconds), IVATP (150µg/kg/min) for 2 minutes, IVATP (210µg/km/min) for 2 minutes, and ICN (2mg/5seconds) during IVATP (150µg/kg/min). Maximal hyperemia was defined as the lowest FFR measured among each method.

Results

During the protocol, 92% of patients achieved maximal hyperemia with ICN2mg, 54% with IVATP 150µg/kg/min, 91% with IVATP 210µg/kg/min, and 99% with ICN2mg during IVATP 150µg/kg/min, respectively. The FFR obtained with ICN2mg were strongly correlated with those obtained with ICN2mg during IVATP150µg/kg/min (r²=0.93, P< 0.001). The mean aortic pressure drop during hyperemia was significantly lower in ICN2mg than in IVATP 150µg/kg/min, IVATP 210µg/kg/min, and ICN2mg during IVATP 150µg/kg/min(9 ± 10, 11 ± 14, 24 ± 17, and 27 ± 19mmHg, p < 0.001, respectively). Despite no side effects reported during hyperemia with ICN2mg alone, transient atrioventricular block was observed in 1(1%) patient with IVATP 150µg/kg/min and 9(4%) patients with IVATP 210µg/kg/min. Also, 20 (10%) patients with  IVATP 150µg/kg/min and 56(27%) with IVATP210µg/kg/min experienced chest discomfort during hyperemia.

Conclusions

The intracoronary administration of NIC2mg is safe and well tolerated, and shortens the procedure. Furthermore, intracoronary NIC2mg produced a more pronounced hyperemia than IVATP and may be the preferred mode of application for the assessment of FFR.

1677 Global longitudinal strain during dobutamine stress echocardiography can predict left ventricular remodeling after anterior wall acute myocardial infarction

Background

Although dobutamine stress echocardiography (DSE) at the early stage of acute myocardial infarction (AMI) is useful for the prediction of functional and clinical prognosis, the interpretation requires expertise. In this study, we sought to investigate if global longitudinal strain (GLS) during DSE after AMI can predict left ventricular remodeling (LVR).

Methods

Consecutive 30 patients with anterior wall AMI (18 male, age = 58 ± 13 years) were performed DSE 3 days after AMI. GLS was calculated as an averaged value of peak longitudinal strain in the apical 4- and 2-chamber views at baseline echocardiography, low-dose DSE (10 μg/kg/min) using available software (QLAB, Philips Medical Systems). Left ventricular remodeling (LVR) was defined as an echocardiographically determined increase in both EDVI and ESVI of 20% or more from baseline to the 6 month follow-up echocardiography.

Results

12 patients (40%) evolved with LVR. The change in GLS during low-dose DSE was significantly different between the remodeling and non-remodeling group (8 ± 5% v.s. 27 ± 20%, p < 0.05). Interestingly, it predicted LVR with sensitivity of 88%, specificity of 92% at the cut-off value of 12% (Area under the curve = 0.94, p < 0.0001).

Conclusion

The change in GLS during low-dose DSE can be used as a predictor for the LVR after AMI. This observation has promise for clinical applications.

Abstract 1677 Figure.

SHAPE ESTIMATION OF BOWTIE FILTERS BASED ON THE LUMINESCENCE FROM POLYETHYLENE TEREPHTHALATE RESIN BY X-RAY IRRADIATION

In this study, we devised a novel method estimating the bowtie filter shapes by imaging luminescence from a polyethylene terephthalate (PET) resin with X-ray irradiation in a computed tomography (CT) scanner. The luminescence distribution of the PET resin corresponding to the thickness of bowtie filter was imaged using a charge-coupled device camera. On the assumption that the material of bowtie filter is aluminium (Al), the shape of bowtie filters was estimated from the correlation between Al attenuation curves and the angular-dependent luminance attenuation profiles according to the thickness of bowtie filters. Dose simulations based on the estimated bowtie filter shapes were performed using head and body PMMA phantoms with 16 and 32 cm in diameter. The simulated values of head and body weighted CT dose index (CTDIw) based on bowtie filter shape by the luminescence imaging method agreed within ~9% with the measured values by a dosemeter.

Visualization of Lenticulostriate Arteries on CT Angiography Using Ultra-High-Resolution CT Compared with Conventional-Detector CT

BACKGROUND AND PURPOSE

The newly developed ultra-high-resolution CT is equipped with a 0.25-mm detector, which has one-half the conventional section thickness, one-half the in-plane detector element width, and one-half the reconstructed pixel width compared with conventional-detector CT. Thus, the ultra-high-resolution CT scanner should provide better image quality for microvasculature than the conventional-detector CT scanners. This study aimed to determine whether ultra-high-resolution CT produces superior-quality images of the lenticulostriate arteries compared with conventional-detector CT.

MATERIALS AND METHODS

From February 2017 to June 2017, thirteen patients with aneurysms (4 men, 9 women; mean age, 61.2 years) who underwent head CTA with both ultra-high-resolution CT and conventional-detector CT were enrolled. Two board-certified radiologists determined the number of all lenticulostriate arteries on the CTA coronal images of the MCA M1 segment reconstructed from 512 matrixes on conventional-detector CT and 1024 matrixes on ultra-high-resolution CT.

RESULTS

There were statistically more lenticulostriate arteries identified on ultra-high-resolution CT (average, 2.85 ± 0.83; 95% CI, 2.509-3.183) than on conventional-detector CT (average, 2.17 ± 0.76; 95% CI, 1.866-2.480) (P = .009) in 16 of the total 26 MCA M1 segments.

CONCLUSIONS

Improvements in lenticulostriate artery visualization were the result of the combined package of the ultra-high-resolution CT scanner plus the ultra-high-resolution scanning protocol, which includes higher radiation doses with lower than the national diagnostic reference levels and stronger adaptive iterative dose-reduction processing. This package for ultra-high-resolution CT is a simple, noninvasive, and easily accessible method to evaluate microvasculature such as the lenticulostriate arteries.

Isotope Effect on Energy Confinement Time and Thermal Transport in Neutral-Beam-Heated Stellarator-Heliotron Plasmas

The isotope effect on energy confinement time and thermal transport has been investigated for plasmas confined by a stellarator-heliotron magnetic field. This is the first detailed assessment of an isotope effect in a stellarator heliotron. Hydrogen and deuterium plasmas heated by neutral beam injection on the Large Helical Device have exhibited no significant dependence on the isotope mass in thermal energy confinement time, which is not consistent with the simple gyro-Bohm model. A comparison of thermal diffusivity for dimensionally similar hydrogen and deuterium plasmas in terms of the gyroradius, collisionality, and thermal pressure has clearly shown robust confinement improvement in deuterium to compensate for the unfavorable mass dependence predicted by the gyro-Bohm model.

P5652Catheter ablation outcome and heart failure hospitalization in atrial fibrillation patients with preserved left ventricular ejection fraction: insights from the Kansai plus atrial fibrillation (KPAF)

Background

Heart failure (HF) is the leading cause of death in patients with atrial fibrillation (AF), and AF is an independent prognostic factor in HF patients with preserved left ventricular ejection fraction (LVEF). Radiofrequency catheter ablation (RFCA) for AF is effective to maintain sinus rhythm.

Purpose

We sought to clarify incidence of HF hospitalization and whether AF ablation outcome influenced incidence of HF hospitalization after the procedures in patients with preserved LVEF.

Methods

We conducted a large-scale, prospective, multicenter, observational study. A total of 4522 consecutive patients with normal LVEF (>/- 50%) who underwent an initial RFCA for AF in 26 centers were enrolled (average age, 64±10 years; non-paroxysmal AF, 33.7%). The median follow-up duration was 2.9 years.

Results

The 3-year cumulative incidence of AF recurrence after a single procedure was 40.3%. Hospitalization for HF was observed in 60 patients (1.3%) and was significantly higher in patients with AF recurrence than those without it (2.63% vs 0.44%, log-rank p<0.001). After adjustment by age ≥65 years, estimated glomerular filtration rate ≤60ml/min, history of HF, and female, all of which were statistically associated with a risk of HF hospitalization, AF recurrence after the index RFCA was an independent predictor of HF hospitalization (hazard ratio; 4.75, 95% confidence interval; 2.59–9.42, p<0.001).

Conclusions

Recurrence after RFCA for AF was a significant risk of HF hospitalization among AF patients with preserved LVEF.

Acknowledgement/Funding

This study was supported by the Research Institute for Production Development in Kyoto, Japan.

P3587Tip detection method using the new short-tip IVUS with pull-back system which facilitates the 3D wiring technique in percutaneous coronary intervention for chronic total occlusion

Background

The strategy of intravascular ultrasound (IVUS)-guided wiring for CTO PCI, that is, leading the second guidewire into the true lumen under observing by IVUS from subintimal space, is the last resort. We developed the angiography-based 3D wiring method. During establishment of the angiography-based 3D wiring method, we deduced that observation of the guidewire tip as well as the shaft named “The tip detection method” simplifies and facilitates 3D wiring under IVUS-guided wiring. Therefore, we produced New CTO IVUS which is the upgraded version of Navifocus WR IVUS by adding the pull-back transducer system. This pull-back system enables us to detect the tip as well as the shaft of the second guidewire in real time (tip detection method), which facilitates the 3D wiring technique under IVUS-guided wiring.

Objective

We evaluated the efficacy of the tip detection method during 3D wiring for CTO PCI with New CTO IVUS.

Method

We created a target pinpoint penetration model and performed the procedures using an experimental heartbeat model. The target (a tube with a lumen 0.6 mm in diameter) was placed in the distal part of a CTO 20 mm in length made of 2.5% agar. After the second guidewire (Conquest-12g) was advanced into the CTO lesion to within 5mm of the target using the angiography-based wiring, IVUS-guided wiring was performed by using Navifocus WR or New CTO IVUS each five times.

Result

The frequency of the puncture time was reduced using the new CTO IVUS compared to the Navifocus WR (1.7±0.8 vs. 28.8±23.2, p=0.17). The procedure time was significantly shorter using the new CTO IVUS compared to the Navifocus WR (103±61 vs. 459±373 seconds, p=0.04).

Conclusion

The tip detection method during 3D wiring with the new short tip IVUS with the pull-back system enables us to easily perform 3D wiring and will change the CTO PCI strategy.

P5632Different impact of lesion length on fractional flow reserve in intermediate coronary lesions between each coronary artery

Background

Previous studies reported that lesion length was an important geometric parameter in addition to the degree of stenosis in the determinant of functional significance of coronary artery stenosis. Nevertheless, the optimal cutoff value of lesion length for predicting functional significance for each coronary artery has not yet been evaluated, though previous studies revealed that the cutoff value of minimum lumen diameter measured on coronary angiography (CAG) to predict fractional flow reserve (FFR) <0.80 is different for each coronary artery

Purpose

This study evaluated whether the impact of lesion length on functional significance is similar between each coronary artery for lesions with intermediate stenosis.

Methods

Patients with suspected coronary artery disease who had at least one intermediate coronary lesion (luminal diameter stenosis of 70 to 80% by visual estimation on CAG) and underwent FFR measurement for the evaluation of myocardial ischemia were evaluated. Quantitative coronary angiography analysis including percent diameter stenosis and lesion length was performed. FFR was measured as the ratio of the mean distal coronary artery pressure to the mean aortic pressure during maximal hyperemia induced by intravenous infusion of adenosine triphosphate (150 μg /kg/min). The area under the receiver operating characteristics (ROC) curve was estimated for the best cutoff value as a predictor of FFR value of ≤0.80 for each coronary artery.

Results

A total of 221 de novo lesions that underwent FFR measurement were enrolled. The average FFR value was 0.81±0.07. Although lesion length was similar among the lesions with an FFR >0.80 at different locations, the mean lesion length was significantly longer for lesions in the right coronary artery (RCA) with an FFR ≤0.80 than for those in the left anterior descending artery (LAD) and left circumflex artery (13.4±3.4 versus 8.6±3.1 versus 12.0±3.7 mm, p<0.001). ROC analysis demonstrated that the optimal cutoff value of lesion length for predicting an FFR ≤0.80 was 10.0 mm in the LAD (0.56 area under the curve, 48% sensitivity, 76% specificity), whereas 13.1 mm in the RCA (0.84 area under the curve, 67% sensitivity, 93% specificity) (Figure).

ROC analysis of LL for FFR≤0.80

Conclusions

A longer lesion length is required to achieve FFR<0.80 in the RCA than in the other arteries. This may suggest the low possibility of an FFR ≤0.80 when stenosis is focal and short in the RCA with stenosis of 70 to 80% by visual estimation on CAG.

P2810Clinical outcomes 1 year after filter protection during percutaneous coronary intervention in patients with attenuated plaque identified by intravascular ultrasound

Background

In the VAMPIRE 3 (VAcuuM asPIration thrombus REemoval 3) trial, we have previously shown that selective use of distal filter protection during percutaneous coronary intervention (PCI) decreased the incidence of no-reflow phenomenon and was associated with fewer in-hospital serious adverse cardiac events than conventional PCI in patients with attenuated plaque ≥5mm. However, whether the early efficacy of distal embolic protection translate into long term clinical benefit is unknown.

Methods

Patients with acute coronary syndrome (ACS) with attenuated plaque ≥5mm were assigned to distal protection (DP) (n=98) or conventional treatment (CT) (n=96). The primary end point of the incidence of no-reflow phenomenon during PCI and the secondary end point of in-hospital serious adverse cardiac events has been reported previously. The rate of a major adverse events, a composite of death from any cause, non-fatal myocardial infarction, or unplanned target vessel revascularization (TVR) at 1 year was the prespecified secondary end point of the trial. All clinical endpoint events were adjudicated by an independent Clinical Event Committee.

Results

Major adverse events at 1 year occurred in 12 patients (12.2%) in the DP group and in 3 patients (3.1%) in the CT group (P=0.029). The difference was driven by a higher risk of TVR (11 [11.2%] vs. 2 [2.1%], p=0.018) in the DP group compared with the CT group. In patients treated with bare metal stents (n=42), major adverse events occurred in 25.0% of the patients in the DP group and in none of the patients in the CT group (P=0.029), whereas in patients treated with drug eluting stents (n=152), rates of major adverse events were similar between the groups (8.1% vs. 3.9%, p=0.32). Rates of cardiac death were not significantly different (1.0% vs. 1.0%, p=1.00). No definite stent thrombosis was observed in either group.

Conclusions

In the VAMPIRE 3 trial of patients with ACS with attenuated plaque ≥5mm, the 1-year rates of major adverse events in the distal protection group were higher than in the conventional treatment group. This effect could be mitigated by the use of drug eluting stents.

Acknowledgement/Funding

This work was supported in part by a grant from Nipro, Boston Scientific Corporation, and Japan Lifeline.

P1029Catheter ablation outcome and heart failure hospitalization in atrial fibrillation patients: insights from the Kansai plus atrial fibrillation (KPAF) registry

Background

Heart failure (HF) is the leading cause of death in patients with atrial fibrillation (AF). Radiofrequency catheter ablation (RFCA) for AF is effective to maintain sinus rhythm.

Purpose

We sought to clarify whether AF ablation outcome influenced incidence of HF hospitalization after the procedures.

Methods

We conducted a large-scale, prospective, multicenter, observational study. A total of 5010 consecutive patients who underwent an initial RFCA for AF in 26 centers were enrolled (average age, 64±10 years; non-paroxysmal AF, 35.6%). The median follow-up duration was 2.9 years.

Results

The 3-year cumulative incidence of AF recurrence after a single procedure was 40.2%. The 3-year incidence of hospitalization for HF was observed in 92 patients (1.8%) and was significantly higher in patients with AF recurrence than those without it (3.3% vs 0.84%, log-rank p<0.001). After adjustment by advanced age,(≥65 years), reduced left ventricular ejection fraction (≤50%), low estimated glomerular filtration rate (≤60ml/min), and history of HF, all of which were statistically associated with a risk of HF hospitalization (p<0.1, respectively), AF recurrence after the index RFCA was an independent predictor of HF hospitalization (hazard ratio [HR]; 3.17, 95% confidence interval [CI]; 2.06–5.04, p<0.001).Even after multiple procedures (1425 re-ablation sessions in 1274 patients [25.4%]), AF recurrence after the last procedure was an independent predictor of HF hospitalization (HR; 2.83, 95% CI; 1.89–4.24, p<0.001).

Conclusions

Among AF patients receiving RFCA, those with AF recurrence were at greater risk of heart failure hospitalization than were patients without AF recurrence. These differences should be noted when treating AF patients in actual clinical practice.

Acknowledgement/Funding

This study was supported by the Research Institute for Production Development in Kyoto, Japan.

3284Quantification of macrophage presence and identification of thin-cap fibroatheroma by optical coherence tomography image: histopathological validation study

Background

Intracoronary optical coherence tomography (OCT) is thought to be capable of identifying a vulnerable, rupture-prone plaque based on the presence of a thin-cap fibroatheroma (TCFA). Moreover, recent studies have reported that OCT may be able to identify macrophage infiltration of the fibrous cap, a key characteristic of vulnerable plaque.

Purpose

This study evaluated the accuracy of OCT image for characterizing TCFA and identifying macrophage infiltration in comparison with histopathology.

Methods

A total of 924 focal plaques in 206 coronary arteries from 78 autopsy hearts were examined to compare OCT and histological images. By histology, 16 plaques (1.7%) were classified as TCFAsthat contained a large necrotic core covered by a thin (<65μm) fibrous-cap. Correlating OCT-histological sections were identified and OCT-derived tissue property indexes named normalized standard deviation (NSD) and signal attenuation ratio were applied on the fibrous-cap to identify inflamed fibrous-cap defined as a macrophage percentage >10% by histology.

Results

With histology as standard, the sensitivity, specificity, and negative-predictive-value of TCFAs were extremely high (more than 90%). However, the positive-predictive-value of TCFAs was only 32%, which indicated a high proportion of false-positives. Most false-positive diagnoses of OCT for TCFAs contained large amounts of foam cell accumulations on luminal surface without necrotic core. Twelve of 16 fibrous-caps were considered as inflamed and the remaining 4 were non-inflamed on histology. However, no significant difference in NSD and signal attenuation ratio were identified between them. There was moderate correlation of the fibrous-cap thickness between OCT and histology (r2 = 0.41 and p<0.01).

Conclusions

OCT is a promising intracoronary imaging modality for differentiating tissue characteristics (fibrous, calcified, or lipid-rich plaque) and identifying TCFA. However, it is still challenging to precisely identify inflammation, fibrous-cap thickness, and necrotic core in the native coronary artery. Therefore, careful interpretation is required to assess coronary vulnerable plaque by OCT.

Acknowledgement/Funding

None

107Diagnostic accuracy of optical coherence tomography for the identification of in-stent fibroatheroma following stent implantation: an ex-vivo histological validation study

Background

Previous histopathological studies have demonstrated that new atherosclerotic formation within the neointima, called neoatherosclerosis, is one of the most important mechanisms leading to both very late in-stent restenosis and stent thrombosis after stent implantation. Therefore, to distinguish lipid-containing atherosclerotic neointima from other tissues using intracoronary imaging modalities is clinically important to prevent late stent failures.

Purpose

This study evaluated the diagnostic performance of optical coherence tomography (OCT) for the detection of “in-stent fibroatheroma” following stent implantation by comparing cross-sections of the model with the corresponding histological images.

Methods

Fifty stented coronary arteries from the 31 autopsy hearts were imaged by OCT. Coronary arterial histopathological specimens, all of which included more than 30% of %neointimal hyperplasia, were compared with the corresponding OCT cross-sections. Histological in-stent fibroatheroma was defined as neointima containing large necrotic core and inflammatory cells. OCT-derived in-stent fibroatheroma comprised a low-intensity tissue containing a poorly delineated region with invisible stent strut behind low signal intensity.

Results

A total of 122 OCT cross-sections were compared with histological images. OCT examination revealed that 24 images (20%) contained low-intensity tissue inside the neointima. Of those, 5 images, in which stent strut behind low signal intensity was invisible, were diagnosed as OCT-derived in-stent fibroatheroma (4%) (Figure A). By histological analysis, only 4 images were classified as in-stent fibroatheroma (3%) (Figure B). With histology as the gold standard, the sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy for OCT-derived in-stent fibroatheroma were 100%, 99%, 80%, 100%, and 99%, respectively. The only histological finding underlying the false-positive-diagnosis of OCT-derived in-stent fibroatheroma was foam cells accumulation without necrotic core on the neointimal surface (Figure C and D). Most tissue that showed low-intensity tissue with visible stent strut by OCT contained proteoglycan matrix and organized thrombus in the absence of an underlying necrotic core.

Coregistration of OCT with histology

Conclusion

This study showed the potential capability of OCT based on the visualization of stent struts behind low-intensity regions for discriminating in-stent fibroatheroma from other neointimal tissues following stent implantation.

P980Post-procedural plasma brain natriuretic peptide level early after catheter ablation predicts the future clinical outcome in patients with persistent atrial fibrillation and reduced ejection fraction

Background

Successful restoration of sinus rhythm (SR) by catheter ablation (CA) for persistent atrial fibrillation (AF) improves cardiac function, resulting in decrease of plasma brain natriuretic peptide (BNP) level. The exact significance and prognostic implications of this change have yet to be determined.

Purpose

To examine the impact of pre- and post-procedural BNP level on the clinical outcome after CA in patients with persistent AF and reduced left ventricular ejection fraction (LVEF).

Methods

Out of 242 patients with LVEF <50% who underwent first-time CA for persistent AF between March 2012 and September 2018 at our institute, we enrolled 137 patients (61±10 years, 83% male) whose plasma BNP level was available both at baseline and early after CA (during 1–3 month). We evaluated the impact of the BNP levels on future AF recurrence 3 months after CA as the primary endpoint. Additional secondary endpoints included heart failure (HF) hospitalization and cardiovascular death.

Results

All patients successfully restored SR at the end of CA. Within 3 months of a blanking period (BP), improvement of LVEF (from 39±10% to 65±12%, p<0.001) and reduction of BNP levels (from 178 [107–332] pg/ml to 42.3 [21.1–78.6] pg/ml, p<0.001) were observed. During the median follow-up of 21 months after BP, the incidence of AF recurrence, HF hospitalization, and cardiovascular death was 37% (n=50), 3% (n=4), and 1% (n=1), respectively. Cox proportional hazard regression analysis after adjustment for age and gender revealed that post-procedural BNP level was a significant predictor of the AF recurrence (hazard ratio [HR] per 100-pg/ml increase, 1.13; 95% confidence interval [CI], 1.02–1.25; p=0.023), but pre-procedural BNP level was not (1.02; 0.95–1.09; p=0.56). Receiver operating curve analysis determined the post-procedural BNP level of 55.5 pg/ml as the best cut-off value for predicting the AF recurrence, with area under the curve of 0.620 (95% CI, 0.534–0.702; p=0.018). The incidence of AF recurrence was significantly higher in patients with post-procedural BNP level >55.5 pg/ml (n=50) than the others (50% vs. 29%; HR, 3.99; 95% CI, 2.07–7.68; p<0.001). No patients with post-procedural BNP level ≤55.5 pg/ml experienced HF hospitalization and cardiovascular death (8% vs. 0% and 2% vs. 0%, p=0.006 and p=0.17, respectively)

Conclusions

Not pre-procedural but post-procedural BNP level early after CA predicted the future clinical outcome in patients with persistent AF and reduced LVEF. Decreased but still elevated BNP level after restoration of SR would identify the residual risk for developing unfavorable outcome.

NOVEL ANALYTICAL STUDY FOR REACTION INTERMEDIATES IN THE PRIMARY RADIATION INTERACTION OF DNA USING A SYNCHROTRON RADIATION-INDUCED LUMINESCENCE SPECTROSCOPY

To identify the precise molecular processes to induce DNA lesions, we attempt a novel spectroscopy of X-ray induced luminescence (XIL) using soft X-ray synchrotron radiation, which is a non-destructive analysis of the reaction intermediates in the elementary reaction pathway of damage induction and self-organized restoration. Using a liquid micro-jet technique to introduce aqueous samples in a vacuum chamber, we measure UV-visible luminescence from nucleotide solution as a function of the soft X-ray energy from the nitrogen to oxygen K-edge region. The XIL intensities for the nucleotide solutions are significantly enhanced in the soft X-ray region (410-530 eV) which is ascribed to the K-shell excitation/ionization of nitrogen atoms in the nucleobases. Furthermore, the XIL spectra do not show any signature of X-ray absorption near-edge structure (XANES) of the nucleobases. This is because the luminescence intensities collected from the integral area of the micro-jet only reflect the quantum yield of luminescence of the absorbed X-ray into UV-visible light irrespective of the absorption cross sections, i.e. of XANES. Thus the present result is the first evidence of luminescence as a result of X-ray absorption of aqueous nucleotides.

A Comparison of the Effects of Prolonged (>10 Hour) Low-flow Sevoflurane, High-flow Sevoflurane, and Low-flow Isoflurane Anaesthesia on Hepatorenal Function in Orthopaedic Patients

This study compared the effects of low-flow sevoflurane, high-flow sevoflurane and low-flow isoflurane on hepatorenal function during and after more than 10 hours of anaesthesia. Twenty-five patients scheduled for elective orthopaedic surgery were categorized into three groups; low-flow sevoflurane (fresh gas flow at 1 litre/min, n=9), high-flow sevoflurane (5 l/min, n=7), or low-flow isoflurane (1 l/min, n=9). Inspiratory compound A concentrations were measured. The groups had similar duration of anaesthesia and exposure to anaesthetic agents. The area under the curve of concentration (mean, SD) of compound A in the low-flow sevoflurane group (359.8, 106.1 ppm.h) was greater than that in the high-flow sevoflurane group (61.1, 29.3 ppm.h; P<0.01). All groups showed normal plasma creatinine and creatinine clearance, and transient postoperative increases in plasma alanine aminotrans-ferase and alpha glutathione-S-transferase, as well as urinary glucose and alpha glutathione-S-transferase, with no significant differences between groups. There were no significant relationships between the area under the curve of concentration of compound A and the biomarkers. These findings suggest that prolonged anaesthesia with low-flow sevoflurane has similar effects on hepatorenal function to prolonged anaesthesia with high-flow sevoflurane and low-flow isoflurane.