P5617Repeatability of instantaneous wave-free ratio in comparison with fractional flow reserve

Background

Instantaneous wave-free ratio (iFR) has been recently introduced as an adenosine free alternative for fractional flow reserve (FFR) to assess the functional significance of epicardial coronary stenosis. Little is known, however, regarding the repeatability and stability of iFR in comparison with FFR.

Purpose

The aim of this study was to evaluate the repeatability of iFR and compare it to that of FFR.

Methods

Patients with stable coronary artery disease who underwent physiological assessment twice within 90 days were enrolled. Repeated measurements were performed at diagnostic and therapeutic catheterization in about 70% of studied population. The remaining patients were measured twice for non-culprit lesion assessment at primary PCI and subsequent non-culprit and ischemia-documented lesion PCI. The calculation of iFRmatlab from DICOM pressure tracing data of resting state was performed using a fully automated off-line software algorithm in a blind fashion. FFR values were also measured by a fully automated algorithm in the same core laboratory by using hyperemic pressure tracing data. The repeatability of the two indices were evaluated and compared. The inter-rater agreement between iFRmatlab and FFR values of two measurements was assessed by κ coefficient. The pressure rate product during each assessment was also documented and evaluated.

Results

Ninety-three lesions from 92 patients were included in the study. The time interval between the two assessments was 38.4±19.0 days. iFRmatlab and FFR both showed significant correlation within the two assessments (iFRmatlab: r=0.75, 95% confidence interval, 0.64 to 0.83; mean difference, −0.006 [−0.18 to −0.01], FFR: r=0.86, 95% confidence interval, 0.79 to 0.90; mean difference, 0.004 [−0.07 to 0.03]). The inter-rater agreement of functional ischemia for iFRmatlab and FFR were κ=0.449 and κ=0.732, respectively. Although the prevalence of functional ischemia during the first and second assessment were consistent for both indices (iFRmatlab: 70.0%/67.7%, FFR: 86.0%/ 86.0%), significant difference was observed in the prevalence of clinical disagreement on the diagnosis of functional ischemia (FFR=0.80, iFR=0.89 used as cut-off values, respectively) between the first and second assessment among the two indices (iFRmatlab: 6.5%, FFR: 23.7%, p=0.002). iFRmatlab was significantly associated with pressure rate product during the examination compared to FFR (iFRmatlab: r= −0.25, 95% confidence interval, −0.43 to −0.04, P=0.018, FFR: r=−0.08, 95% confidence interval, −0.28 to −0.13, p=0.467).

Conclusion

Our results suggested that iFRmatlab showed lower repeatability and reliability for decision making compared to FFR. The instability of iFRmatlab potentially derives at least in part from its association with heart rate and blood pressure product.

P2703Impact of subtended myocardial mass on the assessment of functional ischemia as evaluated by FFR and QFR

Background

The fractional flow reserve (FFR) becomes a standard practice for revascularization decision-making in evaluating the functional significance of angiographically intermediate epicardial coronary stenosis. The quantitative flow ratio (QFR) is a novel method for rapid computational estimation of FFR without pressure wire and hyperemic induction. FFR has been reported to be associated with not only epicardial stenosis but also subtended myocardial mass (Vsub). In contrast, the relationship between QFR and Vsub has not been clarified.

Purpose

We sought to examine if subtended myocardial mass (Vsub) assessed by coronary computed tomography showed a significant relationship with QFR in comparison with FFR.

Methods and results

We performed a post-hoc analysis of 152 territories (LAD 116, RCA 25 and LCX 11 lesions) with angiographically intermediate-to-severe stenosis in 152 patients who underwent FFR assessment. The median FFR and QFR values were 0.76 (0.64–0.84) and 0.76 (0.72–0.83), respectively. The median diameter stenosis (%DS) and minimum lumen diameter (MLD) were 54.5 (43.9–64.2) and 1.2 (0.9–1.6), respectively. In total, 123 (80.9%) and 29 (19.1%) lesions showed concordant and discordant FFR and QFR functional classifications, respectively. The ability of Vsub/MLD2 to discriminate lesions with FFR≤0.80 and QFR≤0.80 was assessed compared with QCA data. FFR values were associated with Vsub (R=0.37, P<0.001). In contrast, a trend albeit no significant linear relationshipwas detected between QFR and Vsub (R=0.15, P=0.060). The area under the curve (AUC) of Vsub/MLD2 predicting FFR≤0.80 (0.88: 95% confidence interval [CI], 0.83–0.94)was significantly better than that of MLD (0.80: 95% [CI], 0.72–0.88) (P<0.001). On the other hand, the AUC of Vsub/MLD2 predicting QFR≤0.80 (0.82: 95% [CI], 0.75–0.90) was similar to that of MLD (0.80: 95% [CI], 0.72–0.87) (P=0.276). Multivariate analysis showed that the value of Vsub/MLD2 was an independent predictor of FFR≤0.80 (odds ratio [OR]: 1.09, 95% [CI]: 1.03–1.15, P=0.002), whereas it was not an independent predictor of QFR≤0.80.

Conclusions

Subtended cardiac mass volume derived from CT segmentation improved the diagnostic performance of angiography-derived parameters to identify ischemia-producing lesions when FFR used as a reference standard, whereas QFR showed non-significant relationship with subtended cardiac mass.

INVESTIGATION OF EXTERNAL RADIATION DOSES DURING RESIDENTS' TEMPORAL STAY TO NAMIE TOWN, FUKUSHIMA PREFECTURE

Namie Town in Fukushima Prefecture, the majority of which was an evacuation area as a result of the effects of the Fukushima Daiichi Nuclear Power Plant accident, carried out a 'temporal stay' in September 2016 so that residents could check their houses. Therefore, in cooperation with the town authorities, the authors distributed personal dosemeters and behaviour record forms to record the personal dose equivalent rate and investigate the relationship between residents' external radiation dose and their behaviour. When the personal dose equivalent rate was calculated from the measured personal dose equivalent per hour, the median was 0.12 μSv h-1, the maximum value and the minimum value were 0.58 and 0.06 μSv h-1, respectively. Meanwhile, since personal fluctuations were observed in personal dose equivalent, grasping the relationship between residents' behaviour and exposed dose can be applied to risk communication.

6113Gender differences in long-term outcomes in patients with deferred revascularization following fractional flow reserve assessment: international collaboration registry of physiologic evaluation

Background

Studies of sex differences in fractional flow reserve (FFR) measurements have shown that in comparison with men, angiographic lesions of similar visual severity are less likely to be ischemia producing in women. Gender specific differences may influence revascularization decision making and prognosis after deferred revascularization following FFR measurement.

Purpose

This study sought to investigate the gender difference in long-term prognosis of patients of deferred revascularization following FFR assessment.

Methods

A total of 879 patients (879 vessels) with deferred revascularization with FFR >0.75 who underwent FFR and CFR measurements were enrolled from 3 countries (Korea, Japan, and Spain). Long-term outcomes were assessed in 649 men and 230 women by the patient-oriented composite outcome (POCO, a composite of any death, any myocardial infarction [MI], and any revascularization). We applied inverse-probability weighting (IPW) based on propensity scores to account for differences at baseline between women and men (age, hypertension, hyperlipidemia, diabetes mellitus, lesion location, clinical status, FFR, Reference diameter, Diameter stenosis, lesion length). The median follow-up duration was 1855 days (745–1855 days).

Results

Median FFR values were 0.88 (0.83–0.93) in men and 0.89 (0.85–0.94) in women, respectively. The occurrences of POCO were significantly high in men compared with that in women (10.5% vs 4.2%, P=0.007). Kaplan–Meier analysis revealed that women had a significantly lower risk of POCO (χ2=7.2, P=0.007). Multivariate COX regression analysis revealed that age, male, diabetes mellitus, diameter stenosis, lesion length, and coronary flow reserve were independent predictors of POCO. After applying IPW, the hazard ratio of male for POCO was 2.20 (95% confidence interval: 1.12 to 4.33, P=0.023).

Conclusion

This large multinational study reveals that long-term outcome differs between women and men in favour of women after FFR-guided revascularization deferral.

Acknowledgement/Funding

None

P2239The association between global coronary flow reserve and coronary inflammation assessed by fat attenuation index on computed tomography in patients with acute coronary syndrome

Background

Impaired global coronary flow reserve (G-CFR) is known to predict worse outcomes in patients with coronary artery disease. Phase contrast cine-magnetic resonance imaging (PC-CMR) of the coronary sinus (CS) is a promising approach for quantifying coronary sinus flow (CSF) and global coronary flow reserve (G-CFR) without the need for ionizing radiation, radioactive tracers, or intravascular catheterization. Although G-CFR impairment has been previously reported to be linked with endothelium dysfunction and subsequent atherosclerosis, the relationship between coronary inflammation and absolute coronary blood flow volume or coronary flow reserve remains elusive.

Purpose

We evaluated the association between G-CFR by quantifying CSF using PC-CMR and the extent of coronary inflammation in patients with ACS treated with emergent percutaneous coronary intervention (PCI).

Methods

The study enrolled 107 ACS patients who underwent uncomplicated emergent PCI within 48 hours of symptom onset and coronary CT angiography were performed before PCI. Proximal 40-mm segments of all three major epicardial coronary vessels were examined. Coronary inflammation was assessed by the CT fat attenuation index of perivascular adipose tissue (FAI−PVAT) defined as the mean attenuation of the perivascular adipose tissue (−190 to −30 Hounsfield units (HU)) in a layer of tissue within a radial distance from the outer coronary artery wall equal to the diameter of the vessel, as previously reported. CMR images were acquired to assess absolute CSF at rest and during maximum hyperemia within 30 days after emergent PCI and revascularization of non-culprit significant lesions. The patients were divided into 4 groups according to the number of inflamed vessels (defined as 0, 1, 2, 3 vessels with FAI ≥−70.1 HU).

Results

In the final analysis of 102 patients (mean age 64, Male 65 (63.7%)) including 77 patients with non-ST-segment elevation myocardial infarction (NSTEMI) (75.5%) and 25 patients with unstable angina pectoris (UAP), 25, 30, 26, 21 patients exhibited none, 1, 2, 3 inflamed vessels with FAI ≥−70.1 HU, respectively. Rest and maximal hyperemic CSF and corrected G-CFR were 1.17 [0.63, 1.71] vs 1.36 [1.05, 1.67] vs 1.21 [0.83, 1.94] vs 1.35 [0.96, 1.67] ml/min/g; P=0.61, 3.26 [2.62, 2.99] vs 3.50 [2.60, 4.03] vs 3.34 [1.78, 4.20] vs 2.48 [1.54, 3.43]; P=0.061, 2.95 [2.05, 4.30] vs 2.63 [1.80, 3.56] vs 2.15 [1.37, 2.91] vs 2.18 [1.46, 2.42]; P=0.018, respectively. G-CFR was significantly lower in group with increased number of inflamed vessels.

Conclusions

In ACS patients successfully revascularized within 48 hours of onset, G-CFR obtained by noninvasive PC-CMR significantly associated with the prevalence of inflamed vessels detected by coronary CT. Further large population study is warranted to test the hypothesis that the extent of coronary inflammation before coronary revascularization in patients with ACS might provide prognostic information.

P5251Prognostic value of unrecognized myocardial infarction detected by cardiac magnetic resonance imaging in patients presenting with first acute myocardial infarction

Background

Unrecognized myocardial infarction (UMI) has been reported to be strongly associated with worse outcome in patients with cardiovascular disease. Cardiac magnetic resonance (CMR) imaging is a useful instrument for the assessment of pathological and functional conditions.

Purpose

This study sought to evaluate the prognostic value of the presence of unrecognized non-infarct-related late gadolinium enhancement (non-IR LGE) evaluated by cardiac magnetic resonance imaging in patients presenting with a first acute myocardial infarction (AMI).

Methods

We studied 311 AMI patients including 213 STEMI and 98 NSTEMI patients without the history of prior MI who underwent uncomplicated primary or emergent PCI within 48 hours of symptom onset between October, 2012 and June, 2017. CMR images were acquired at 28 [21, 32] days after primary/emergent PCI. UMI was defined as having LGE separately in the different and remote area from the perfused territory by infarct-related artery. In case of multiple LGE areas of infarction, the coronary angiography findings were used to support identification of the area corresponding to the culprit artery of AMI. The association of CMR variables and other clinical characteristics with major adverse cardiac events (cardiac death, nonfatal myocardial infarction, nonfatal stroke) were investigated.

Results

Forty-six patients (14.8%) showed UMI defined by the presence of non-IR LGE (27 STEMI and 19 NSTEMI). During the follow up for 830 [385, 1309] days, cardiovascular death occurred in 7 patients (2.3%), and non-fatal MI and non-fatal stroke occurred in 10 and 1 patients, respectively (3.2%, 0.3%, respectively). There was no significant difference in the prevalence of UMI and incidence of MACE between the patients with STEMI and NSTEMI (p=0.13, p=0.11, respectively). Event-free survival was significantly worse in patients with UMI (log-rank χ2=16.3, P=0.001) in a total cohort. Cox proportional hazards analysis showed that UMI was independent predictors of adverse cardiac events during follow-up in patients with first MI (hazard ratio, 7.60, 95% confidence interval, 2.78–20.8, p=0.0001).

Conclusions

In first AMI patients, UMI defined by non-IR LGE obtained by noninvasive CMR provides significant prognostic information. Early detection of UMI by CMR may help risk stratification of patients with AMI and support adjunctive aggressive patient management such as strong statin therapy and life style intervention.

P6393Differences in coronary inflammation between the culprit and non-culprit vessels assessed by fat attenuation index on computed tomography in patients with acute coronary syndromes

Background

Inflammation is linked with progression of coronary atherosclerosis. Recent studies have reported the association between elevated perivascular fat attenuation index (FAI) on computed tomography (CT) and worse cardiac outcomes in patients with coronary artery disease.

Purpose

We aimed to investigate the differences in FAI-defined peri-coronary inflammation status between the culprit and non-culprit vessels in patients with acute coronary syndromes (ACS).

Methods

A total of 78 ACS patients with left anterior descending coronary arteries (LAD) as a culprit vessel who underwent coronary CT angiography and invasive coronary angiography were studied. Proximal 40-mm segments of the LAD and the right coronary artery (RCA) were traced. Coronary inflammation was assessed by the FAI defined as the mean CT attenuation value of perivascular adipose tissue (−190 to −30 Hounsfield units [HU]) in a layer of tissue within a radial distance from the outer coronary artery wall equal to the diameter of the vessel. All patients were divided into two groups according to the values of FAI in the LAD: high FAI group (FAI-LAD > median; n=39) and low FAI group (FAI-LAD ≤ median; n=39). Patient characteristics, angiographic and CT findings were compared between the two groups.

Results

In a total of 78 patients, median FAI in the LAD was −70.20 (interquartile range, −74.81 to −64.58) HU. High FAI group was associated with male sex and lower left ventricular ejection fraction compared with Low FAI group. Minimal lumen diameter, reference diameter, diameter stenosis, and lesion length on quantitative coronary angiography analysis and coronary artery calcium score on CT was not different between the groups. FAI in the RCA was also higher in High FAI group than that in Low FAI group (−67.64±8.31 vs. −76.47±6.25 HU, P<0.001). Paired t-test comparison demonstrated that culprit vessel showed higher FAI than the non-culprit vessel (−69.85±7.74 vs. −72.11±8.54 HU, P=0.013).

Conclusions

In ACS patients with culprit LAD lesions, FAI-defined peri-coronary inflammation status is higher in the culprit vessel than in the non-culprit vessel.

COMPREHENSIVE EXPRESSION ANALYSIS OF MIRNAS IN MICE EXPOSED TO LETHAL RADIATION AND/OR RADIO-MITIGATIVE DRUG

New minimally invasive indicators that are capable of predicting the biological effects and radiation damage to various organs and systems are urgently needed for the development of optimal treatment protocols for victims of radiation accidents. In the present study, we focused on microRNA (miRNA) that have recently emerged as biomarkers for predicting and diagnosing various pathological conditions and identified the serum miRNA signatures. All of the mice treated with lethal radiation alone strongly expressed certain serum miRNAs detectable for 24 h after radiation exposure, whereas the administration of radio-mitigative drug immediately after irradiation suppressed these miRNA expressions to the same levels as in control mice. These results suggest that serum miRNAs may reflect the degree of radiation damage and can be used to predict the radiation-mitigative information in victims of accidental radiation exposure.

P3585Prognostic value of the assessment of coronary sinus flow by phase contrast cine-magnetic resonance imaging in patients with acute coronary syndrome

Background

Phase contrast cine-magnetic resonance imaging (PC-CMR) of the coronary sinus (CS) is a promising approach for quantifying global coronary sinus flow (CSF) and global coronary flow reserve (G-CFR) without the need for ionizing radiation, radioactive tracers, or intravascular catheterization.

Purpose

We evaluated the prognostic value of G-CFR by quantifying CSF using PC-CMR in patients with ACS treated with primary or emergent percutaneous coronary intervention (PCI).

Methods

The study prospectively enrolled 387 ACS patients who underwent uncomplicated primary or emergent PCI within 48 hours of symptom onset. Breath-hold PC-CMR images of CS were acquired to assess absolute CSF at rest and during maximum hyperemia within 30 days after primary PCI and revascularization of functionally significant non-culprit lesions of ACS. The association of G-CFR and baseline clinical characteristics with major adverse cardiac events (cardiac death, nonfatal myocardial infarction, late revascularization, or hospitalization for congestive heart failure) was investigated.

Results

In the final analysis of 366 patients (Male 294 (80.3%), mean age 65) including 233 patients (63.7%) with ST-segment elevation myocardial infarction (STEMI) and 133 patients (36.3%) with non-ST-segment elevation acute coronary syndrome (NSTE-ACS), rest and maximal hyperemic CSF and corrected G-CFR were 1.24 [0.83, 1.71] ml/min/g, 2.56 [1.87, 3.66] ml/min/g, and 2.20 [1.53, 3.17], respectively. During a median follow-up of 16 months, MACE occurred in 84 patients (cardiac death: 9, nonfatal myocardial infarction: 11, late revascularization: 59, hospitalization for congestive heart failure: 5). Cardiac event-free survival was significantly worse in patients with a corrected G-CFR <2.00 (log-rank χ2=20.2, P<0.001). Cox proportional hazards analysis showed that corrected G-CFR were independent predictors of adverse cardiac events during follow-up in patients with STEMI (hazard ratio, 0.66, 95% confidence interval, 0.51–0.85, p=0.001) and NSTE-ACS (hazard ratio, 0.64, 95% confidence interval, 0.43–0.95, p=0.026), respectively.

Conclusions

In ACS patients successfully revascularized within 48 hours of onset, G-CFR obtained by noninvasive PC-CMR provided significant prognostic information independent of infarction size and conventional risk scores.

COMPARISON OF BACTERIAL FLORA IN RIVER SEDIMENTS FROM FUKUSHIMA AND AOMORI PREFECTURES BY 16S RDNA SEQUENCE ANALYSIS

Monitoring of radioactive materials has been reported in rivers and soil in Fukushima post the Fukushima Daiichi Nuclear Power Plant accident in March 2011. However, there are few reports on the influence of this event on bacteria in forest soils and rivers. Therefore, through amplicon sequencing of 16S rDNA we compared the bacterial flora in river sediment soils from Fukushima prefecture and from an area not exposed to radioactive contamination, Aomori prefecture. The bacterial composition in the Aomori prefecture soil and Fukushima soil were found to be very similar at the phylum level. However, Fukushima soil had significantly fewer Bacteroidetes than the Aomori soil (p = 0.014), while the content of Firmicutes and Latescibacteria (WS3) was significantly higher (p = 0.001, 0.013 respectively). However, no increase in the content of radioactive-resistant bacteria was observed. In future studies, it is necessary to standardise the conditions for soil collection to assess its content of radioactive substances.

11 Conception rate of high-producing dairy cows at first service using prostaglandin F2α and oestradiol benzoate

We have shown that a simplified oestrus synchronization protocol using prostaglandin F2α (PG) and oestradiol benzoate (EB) resulted in a satisfactory conception rate, similar to that obtained in high-producing dairy cows with natural oestrus (Yamaguchi et al. 2018 Reprod. Fertil. Dev. 30, 147 abstr). However, we found no significant effect of PG+EB protocols on the first-service conception rates (CR) of dairy cows. This study investigated the effect of the first-service CR by using PG+EB protocols in the high-producing dairy cows that had not exhibited oestrus expression after calving. Data concerning the first-service CR were obtained for 481 Holstein cows from 4 commercial dairy herds in Hokkaido and Ibaraki, Japan, from 2014 to 2017. The average number of parity, average interval between calving and the first service, and average milk yield (at 305 days) of the cows were 2.2±1.3, 89.7±26.1 days, and 10314±1994kg, respectively. We carried out the PG+EB protocols on cows not showing evident standing heat from Days 50 to 150 postpartum regardless of the presence of a corpus luteum in the ovary. The statuses of ovaries of cows were confirmed using ultrasonography before starting the treatment. Prostaglandin F2α (25 mg; Lutalyse, Pfizer, New York, NY, USA) was injected into cows with a &gt;20mm cutoff for functional corpus luteum diameter at a random stage of oestrus, and EB (1 mg; Ovahormon®, Aska Animal Health Co., Tokyo, Japan) was injected 24h later, and AI was carried out 24 to 48h after EB injection. Cows with a natural oestrus service from Days 50 to 150 postpartum were used as control. All the cows were inseminated after the onset of standing heat or removal of the tail chalk. Pregnancy diagnoses were performed using ultrasonography 30 to 45 days after AI. The CR and intervals of partum to conception were analysed using a chi-square test and ANOVA. The first-service CR (i.e. the number of pregnant cows/total number of cows in the treatment group) of the natural oestrus (n=330) and PG+EB (n=151) groups were 42.7 and 41.1%, respectively, and there were no significant differences between these 2 groups (P=0.7). The average interval between calving and the first service of the PG+EB groups was significantly longer than that of the natural oestrus groups (86.4±1.5 days v. 96.9±1.9 days; P&lt;0.01). The average days open of the natural oestrus and PG+EB groups were 88.5±3.2 days and 98.1±2.3 days, respectively (P&lt;0.05). These results confirmed that the first-service CR in the PG+EB and natural oestrus groups of high-producing dairy cows were similar. We suggest that conducting PG+EB protocols was effective in the high-producing dairy cows that had not exhibited oestrus expression after calving. Moreover, using PG+EB protocols could prevent the further increase in the number of days open.