Cardiopulmonary arrest and in-hospital outcomes in young patients with acute myocardial infarction: insights from the Japanese nationwide registry

Background

Cardiopulmonary arrest (CPA) is the most serious presentation of acute myocardial infarction (AMI). However, the frequency and prognostic impact of CPA in young patients with AMI have been still unclear.

Objectives

This study aimed to characterize AMI in young patients who underwent primary percutaneous coronary intervention using large-scale nationwide all-comer registry data in Japan (J-PCI registry).

Methods

Data on risk factor profiles, clinical features, post-procedural complications, and in-hospital outcomes were reviewed within the J-PCI registry between 2014 and 2018.

Results

Among 213,297 patients with AMI, 23,985 (11.2%) were young (age, 20–49 years). Compared with the older group (age, 50–79 years; n=189,312), the young group included a higher number of men, smokers, patients with dyslipidemia, and patients with single-vessel disease, and a lower number of patients with hypertension and diabetes. Despite favorable clinical profiles, younger age was associated with a higher rate of presentation with CPA (Figure 1). Further, concomitant CPA was strongly associated with in-hospital mortality in the young group (Table 1).

Conclusions

Young patients with AMI presented a higher risk of CPA than older patients, which was strongly associated with in-hospital mortality.

Funding Acknowledgement

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

OP0238 CLINICAL ANALYSIS OF 34 CASES OF CARDIAC COMPLICATIONS REQUIRING SURGICAL INTERVENTION IN SYSTEMIC LUPUS ERYTHEMATOSUS AND ASSESSMENT ABOUT MECHANISM OF DEVELOPMENT WITH IMMUNOLOGICAL ANALYSIS

Background

In cases of systematic lupus erythematosus (SLE) that lead to surgery due to the development of heart diseases such as valvular disease, ischemic heart disease and aortic aneurysm, early detection and careful monitoring are important. An absence of background diseases or immunopathological examination of the myocardial tissue in SLE cases with cardiovascular lesions demonstrates the lack of knowledge in this area. In recent years, however, there have been reports of neutrophil extracellular traps being involved in the fulminant onset of SLE.

Objectives

This study aimed to analyze clinically and immunohistopathologically the pathophysiology of heart diseases associated with SLE.

Methods

We performed left atrial appendage resection in 34 patients, including patients with cardiovascular lesions, who underwent heart surgery for SLE complications from 2012 to 2021. Tissue analysis was conducted in 9 cases. The left atrial appendage, in cases of non-collagen valvular disease, was used as the control. Tissue staining of cardiomyocytes was carried out by adding anti-neutrophil extracellular(NE) antibodies(Abs) to anti-human IgG antibody (Ab), anti-IgM Ab and anti-C3 Ab.

Results

Of the 34 SLE patients 14 had valvular disease, 8 had ischemic heart disease and 12 had aneurysms. Preoperative SLE activity was relatively stable with only 1 patient below the CH50 standard and 6 patients above the anti-DNA Ab standard. The Ab positivity rate for the patients in this study was higher than that of the 687 SLE patients who were previously tested in 2019. The presence of anti-CL Abs was 55.6%, which was higher than the 25.5% observed in previous SLE patients. In this study, anti-SS-A and anti-RNP Abs tended to be relatively numerous. An example of immunohistochemical staining of IgG in the left atrial appendage is presented (Figure 1a). IgG deposits were not observed on the left side of the myocardial fibers in the control group, whereas IgG deposits were observed on the right side in the SLE group. Deposits were also observed in tissues that were not located in the affected areas. The presence or absence of tissue deposition in the myocardial fibers and clinical findings in 2 cases of the control group and 9 cases of the SLE complication group are reported in Table 1. IgG deposits were found in the myocardial fibers of 6 of the 9 patients in the SLE complication group, and deposits were found in the left atrial appendage tissue regardless of the type of heart disease, suggesting a potential change in the heart tissue. In the SLE group, 5 cases were positive for antiphospholipid (APS) Abs, while 7 cases were positive for either anti-SS-A or anti-RNP Abs. Only 2 cases had elevated preoperative anti-DNA Ab and complement reduction. Of the SLE complication group, 2 of the 9 cases were negative for all Abs but IgG deposits were observed in a case. Of these 4 cases were selected and stained with anti-IgM, anti-C3 and anti-NE Abs. However IgM and C3 deposits were only observed in one patient who developed myocardial infarction at the age of 39 and was triple positive for APS, anti-SS-A and anti-RNP Abs (Figure 1b). There were also no NE deposits in any of the cases. Even if complement and anti-DNA Ab levels in the serum are normal, attention should be paid to heart disease complications during the long-term observation of SLE patients. In particular, attention should be paid to various autoantibody-positive cases such as APS, anti-SS-A Ab and anti-RNP Ab. The anti-NE Ab was not stained in this study because the tissue was different from the lesion site and because it occurred during the chronic course.

Conclusion

In SLE patients who developed cardiovascular lesions and required surgery, immunological abnormalities may occur in the myocardial tissue even if serum complement and anti-DNA Ab levels are stable.

References

[1]Stephane Zuily et al. Valvular Curr Rheumatol Rep (2013) 15:320.

[2]Zawadowski GM et al. Lupus. 2012;21(13):1378-84.

[3]Daniel Appelgren et al. Autoimmunity 2018,vol51,No.6,310-318.

Disclosure of Interests

None declared

Phialocephala fortinii increases aluminum tolerance in Miscanthus sinensis growing in acidic mine soil

Miscanthus sinensis growing in our study mine site contained a high concentration of Al in the adventitious roots. It has a root endophyte, Phialocephala fortinii, in its adventitious roots at a high frequency. The purpose of this study was to elucidate the effects of P. fortinii on Al tolerance mechanisms of M. sinensis and reveal potential underlying mechanisms. In the absence of P. fortinii, M. sinensis produced chlorogenic, citric, and malic acids that could act to alleviate Al toxicity in acidic mine soil. Up on fungal inoculation, the levels of these compounds were reduced, although the growth of seedlings and Mg concentration in the roots were increased. IAA production by the fungus may contribute to enhanced plant growth whereas an increase of Mg uptake could reduce toxicity of reactive oxygen species under Al stress. These actions of P. fortinii could promote growth and survival of M. sinensis in mine sites.

Changes in right ventricular deformation during hyperoxia versus normoxaemia in patients with stable coronary artery disease and healthy controls

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Local research funds of the Department of Anaesthesiology and Pain medicine, Bern University Hospital, Inselspital

Background

During anaesthesia, emergency and critical care treatment, patients with coronary artery disease (CAD) are often exposed to supraphysiologic arterial oxygen tensions. The balance between benefits and risks of hyperoxia (HO) in patients with stable CAD is controversial, with reports about reduced left ventricular contractility or increased morbidity and mortality. Effects of HO on right ventricular (RV) function in CAD are less well described. Advanced cardiovascular magnetic resonance (CMR) feature tracking software allows assessment of myocardial deformation, which may serve as early marker of ventricular dysfunction. In a CMR study we quantified the effect of HO on RV function and deformation in awake healthy participants and CAD patients.

Methods

Ten healthy participants and 26 patients with stable one- or two-vessel obstructive CAD were included. In a CMR study, a short-axis function stack of both ventricles was obtained first at room air (RA), then during HO induced by breathing oxygen at 10L/min for 5 minutes via a non-rebreathing facemask. RV strain was analysed by a blinded reader who manually traced epicardial and endocardial contours of the RV for determining peak global circumferential strain (RVGCS), time to peak strain, systolic and diastolic strain rate parameters.

Results

RV ejection fraction did not change with O2 breathing in the healthy control group (RA, 56 ± 12% vs. HO, 55 ± 10%, p = 0.999) nor in the CAD group (RA, 60 ± 8% vs. HO, 60 ± 9%, p = 0.609). RV cardiac index decreased significantly in CAD patients from RA (2.62 ± 0.88 L/min/m2) to HO (2.42 ± 0.77L/min/m2, p = 0.002). The decrease in the control group was not significant (RVCI: RA 3.28 ± 1.29 vs HO 3.04 ± 1.27L/min/m2 p = 0.068).

In the healthy control group, RVGCS, time to peak strain, and systolic strain rate did not change significantly with HO (RVGCS: RA, -14.6 ± 3.9% vs. HO, -13.1 ± 4.5%, p = 0.353; time to peak strain: 282 ± 45ms vs. 286 ± 29ms, p = 0.540; and systolic strain rate: -0.85 ± 0.27/s vs. -0.67 ± 0.28, p = 0.055).

In CAD patients RVGCS worsened from -14.8 ± 3.3% on RA to -13.9 ± 3.6% at HO (p = 0.040). Time to peak strain became significantly prolonged from 319 ± 40ms on RA to 329 ± 49ms at HO (p = 0.046). This was accompanied by a reduction of systolic strain rate from -0.79 ± 0.27/s to -0.75 ± 0.22/s (p = 0.037). Diastolic strain parameters did not differ significantly between RA and HO in either group.

Conclusion

In our cohort of CAD patients HO significantly reduced RV cardiac index and impaired systolic deformation as determined by CMR feature tracking. Studies are required in a larger patient cohort with regional analysis and assessment of longitudinal and radial deformation to assess the role of hyperoxia in CAD.

Abstract Figure. Change in RV Peak Circumferential Strain

Impact of tapered-shaped left ventricular outflow tract on permanent pacemaker implantation after the third-generation balloon-expandable valve implantation

Background

In the era of transcatheter aortic valve implantation (TAVI) for patients with lower surgical risk, conduction disturbances requiring permanent pacemaker implantation (PPI) after TAVI remain a serious concern. The association between tapered-shaped left ventricular outflow tract (LVOT) and PPI after TAVI has not been elucidated.

Purposes

This study sought to identify predictors for PPI after TAVI with the third-generation balloon-expandable valve, with focus on LVOT morphology.

Methods

Of 272 consecutive patients treated with the third-generation balloon-expandable valve, 256 patients without previous PPI or bicuspid valve were retrospectively analyzed.

Results

PPI was implanted after TAVI in 20 (7.8%) patients. Patients requiring PPI had smaller LVOT area (356.3 mm2 vs. 399.4 mm2, p=0.011). Moreover, receiver-operating characteristic (ROC) statistics showed that LVOT area /annulus area possessed significantly higher predictive ability than LVOT area (area under the curve: 0.91 [95% confidence interval [CI]: 0.84 to 0.95] vs. 0.67 [95% CI: 0.57 to 0.77], p<0.001). Multivariable analysis revealed LVOT area /annulus area (odds ratio [OR]: 1.93 [95% CI: 1.38–2.71]; p<0.001 per % of decreasing), the difference between membranous septum length and implantation depth (ΔMSID) (OR: 6.82 [95% CI 2.39–19.48]; p<0.001 per mm of decreasing) and pre-existing complete right bundle branch block (CRBBB) (OR: 32.38 [95% CI 2.30–455.63]; p=0.002) as independent predictors of PPI. Further analysis using ROC statistics revealed LVOT area / annulus area of 88.5% and ΔMSID of 1.8 mm as the optimal cutoff points for prediction of PPI after the third-generation balloon-expandable valve implantation, with high negative predictive values of 98.1% and 99.0%, respectively. Figure shows the PPI rates stratified by the number of following predictors: LVOT area /annulus area <88.5%, ΔMSID <1.8 mm and pre-existing CRBBB. Patients with 2 or more predictors had significantly higher PPI rates than those with 1 or less predictor (67% [18 of 27 patients] vs. 1% [2 of 229 patients], p<0.001).

Conclusions

LVOT area /annulus area, ΔMSID and pre-existing CRBBB were identified as powerful independent predictors for PPI after TAVI. Higher valve implantation is important to prevent excessive PPI especially for patients with pre-procedural tapered-shaped LVOT, short membranous septum or pre-existing CRBBB.

PPI rates stratified by predictors

Funding Acknowledgement

Type of funding source: None

Impact of SYNTAX score 2 on 7-year clinical outcomes in patients treated with cobalt-chromium everolimus-eluting stent

Background

Impact of SYNTAX score II (SSII) on long-term clinical outcomes after cobalt-chromium everolimus-eluting stent (CoCr-EES) implantation remains unclear.

Methods

Between February 2010 and May 2011, 1064 consecutive patients with 1440 lesions were treated only with CoCr-EES implantation. Of these, the SSII was calculated in 1013 patients with 1345 lesions. Patients were divided into the tertile group: Tertiles for SSII (low SSII [12–28.9], n=334; intermediate SSII [29–39.1], n=339; and high SSII [39.2–80.8], n=340). We assessed the cumulative 7-year incidences of major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, definite stent thrombosis, and clinically driven target lesion revascularization (CDTLR) based on SSII groupings.

Results

Cumulative 7-year incidence of MACE was significantly higher in the high SSII group than in the other groups (34.1% vs. 18.6% vs. 17.2%, p<0.001). The cumulative incidence of cardiac death, myocardial infarction and stent thrombosis were significantly higher in the high SSII group than in the other groups (22.1% vs. 2.0% vs. 5.3%, p<0.001; 6.6% vs. 4.9% vs. 1.7%, p=0.01; 2.9% vs. 1.7% vs. 0.3%, p=0.03, respectively). The cumulative incidence of CDTLR was similar between the groups (15.2% vs. 12.8% vs. 15.7%, p=0.57). High SSII group (hazard ratio [HR] 2.18 [vs. low SS], 95% confidence intervals [CI]: 1.56–3.06, p<0.001) and diabetes mellitus (HR 1.37, 95% CI: 1.04–1.81, p=0.03) were predictors of 7-year MACE.

Conclusions

SSII has significantly impact on 7 years clinical outcomes after CoCr-EES implantation.

Cumulative incidence of MACE

Funding Acknowledgement

Type of funding source: None

Quality and clinical outcomes of primary percutaneous coronary intervention after ST-segment elevation myocardial infarction: a population density analysis of a Japanese nationwide registry

Background

Despite progress in acute myocardial infarction (MI) treatment, data on geographical disparities in its care remain limited.

Purpose

We aimed to assess the discrepancy by population density (PD) on the quality and clinical outcomes of patients with primary percutaneous coronary intervention (PCI) after ST-segment elevation MI (STEMI).

Methods

The J-PCI registry is a prospective procedural registry conducted by the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) to assure the quality of delivered care. Between January 2014 and December 2018, 209,521 patients underwent PCI for STEMI in 1,126 institutes. Population of administrative municipal-level districts was determined through the complete population census. The patients were divided into tertiles according to the PD of the PCI institution location (low: <951.7/km2, n=69,797; middle: 951.7–4,729.7/km2, n=69,750; high: ≥4,729.7/km2, n=69,974).

Results

Patients treated in high PD administrative districts were younger (low: 69.1±12.9, middle: 68.7±12.9, high: 68.0±13.1) and likely to be male (low: 75.6%, middle: 76.0%, high: 76.6%). No significant correlation was observed between PD and door-to-balloon time (DTB: regression coefficients: 0.036 per 1000 people/km2, 95% CI: −0.232 to 0.304, P=0.79). Patients treated in low PD areas had higher crude in-hospital mortality rates than those treated in high PD areas (low: 2.89%, middle: 2.60%, high: 2.38%; P<0.001). Moreover, PD and in-hospital mortality had a significantly inverse association, before and after adjusting for baseline characteristics (crude odds ratio [OR]: 0.983 per 1,000/km2, 95% confidence interval [CI]: 0.973–0.992, P<0001; adjusted OR: 0.980 per 1,000/km2, 95% CI: 0.964–0.996, P=0.01, respectively). Higher PD districts had more operators per institute (low: 6, interquartile range [IQR] 3–10; middle: 7, IQR 3–13; high: 8, IQR 5–13, P<0.001), suggesting an inverse association with in-hospital mortality (OR: 0.992, 95% CI: 0.986–0.999, P=0.03).

Conclusions

Marked geographical inequality was observed in immediate case fatality; patients treated in population-dense areas had a lower in-hospital mortality than those treated in less dense areas. Variation in the number of operators per institute, rather than traditional quality indicators (e.g. DTB) may explain the difference in in-hospital mortality.

Funding Acknowledgement

Type of funding source: None

Prognostic value of intracoronary imaging-derived measures for non-infarct related vessel revascularization throughout 7 years among patients with ST-elevation myocardial infarction

Background

Underlying plaque characteristics that lead to future revascularization during long-term follow-up remain poorly understood.

Purpose

We aimed to explore intracoronary imaging-derived measures as assessed by intravascular ultrasound (IVUS) and optical coherence tomography (OCT) associated with non-infarct related vessel revascularization (non-TVR) arising from imaged segments during long-term (up to 7 years) follow-up among patients with ST-elevated myocardial infarction (STEMI).

Methods

A total of 94 STEMI patients enrolled into the IBIS-4 (Integrated Biomarker Imaging Study-4) study undergoing serial (baseline and 13 months) IVUS and OCT in 2 non-infarct-related coronary arteries under high-intensity statin therapy were analyzed in the present study. Patients were divided into 2 groups according to the occurrence of non-TVR within previously imaged vessel segments (non-TVR: n=14, no non-TVR: n=80).

Results

Baseline characteristics including LDL level were comparable between groups. At baseline, lesions with future non-TVR were associated with greater percent atheroma volume by IVUS (55.6±5.4% vs. 49.6±6.1%, P<0.001), minimum lumen area by OCT (3.4±1.7 mm2 vs. 6.0±3.3 mm2, P=0.004), and a higher prevalence of fibroatheroma (60.0% vs. 20.1%, P=0.007) by OCT compared with those without. Among patients with serial imaging, lesions with non-TVR had a trend towards a less reduction of percent atheroma volume (−0.2±3.8% vs. −2.4±4.2%, P=0.083).

Conclusion

Greater plaque burden, smaller lumen area, and higher prevalence of OCT-detected fibroatheroma at baseline were associated with non-infarct related vessel revascularization. Lesions with non-TVR tend to have less-pronounced regression of coronary atheroma despite intensive statin therapy and achieved LDL levels.

Non-TVR 7 years after index PCI

Funding Acknowledgement

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

AB1109 THE TIME-TO-EVENT ANALYSIS OF THE APPLICATION OF ULTRASOUND TO DISTINGUISHING PMR

Background:

Japan is the world’s most aged country. The number of patients with polymyalgia rheumatic (PMR) is expected to increase more.

Classification criteria including ultrasound findings were published in 2012(1), but the ability to differentiate PMR from other mimicking diseases was unknown.

It is difficult to diagnose PMR accurately. We will clarify whether recently reported ultrasound findings (2, 3) which could be characteristic in PMR are helpful for distinguishing from other mimicking diseases and treatment outcome in suspected PMR patients. Neither diagnostic laboratory test nor specific antibody exist, and inflammatory markers such as C reactive protein and erythrocyte sedimentation rate are not specific.

Objectives:

Patients who were clinically suspected of PMR and underwent ultrasound examination from 2008 to 2018. And Patients who visited the hospital with PMR and were diagnosed with PMR from 2008 to 2018.

Methods:

Patients who visited the hospital and were diagnosed with PMR were extracted from the medical record database of the hospital. Patients who had been administrated GC at the first visit and whose records were not confirmed were excluded. Patients who were clinically diagnosed with PMR without ultrasound(Cli-PMR), patients who were diagnosed with PMR with ultrasound reports(US-Cli-PMR), patients who were diagnosed by the ultrasound expert only based on ultrasound images(US-PMR).

Patient were followed up for one year. Clinical diagnoses were confirmed at the 6 months and 12 months since the first GC administration.

Three groups were compared with each other in the rate of diagnosis change and the time intervals between the initiation of GC treatment and the occurrence of events: recurrence, methotrexate introduction and the normalization of C reactive protein.

the Kaplan–Meier method was used to evaluate the outcomes. Statistical analyses were conducted with R software, version 3.5.2 (R Foundation for Statistical Computing) and EZR(4).

Results:

545 PMR patients were extracted. 403 of 545 was excluded because of preexisting GC therapy and record availability.

At the 6 months follow-up, 92.8% of the non-US PMR group and 97% of US-PMR group remain PMR and at the 12 months follow-up 88.8% and 95% respectively. There was no significant difference in the three time-to-event outcomes.

Conclusion:

Ultrasound did not contribute the improvement of the PMR outcomes. However, this finding was affected by confounding factors for example assignment to ultrasound and atypical cases and rheumatologists’ uncertainness. Despite confounding factors, US-PMR group was not inferior. These findings showed that ultrasound may be useful for the complicated cases.

References:

[1]ARTHRITIS & RHEUMATISMVol. 64, No. 4, April 2012, pp 943–954

[2]Clin Med Insights Arthritis Musculoskelet Disord 2017;10: 1179544117745851.

[3]Biomed Res Int 2017;2017: 4272560.

[4]Bone Marrow Transplantation 2013: 48, 452–458

Disclosure of Interests:

None declared

SAT0262 PROPOSAL FOR OPTIMIZATION OF DIAGNOSTIC IMAGING FOR GIANT CELL ARTERITIS USING THREE-DIMENSIONAL COMPUTED TOMOGRAPHY ANGIOGRAPHY IMAGE AND CONSTRUCTING VASCULAR MAPPING FROM VASCULAR ULTRASONOGRAPHY AS REFERENCES

Background:

The development of rapid and accurate methods of diagnosing giant cell arteritis (GCA) is critical to prevent blindness and stroke, which may develop rapidly in patients with GCA. In 2018, EULAR published recommendations that the first imaging modality for GCA should be vascular ultrasonography without biopsy. However, many institutions still consider biopsy to make an important contribution to the diagnosis of GCA.

Objectives:

Our purpose is to eliminate blindness and stroke among GCA patients by optimizing diagnostic imaging and method to diagnose GCA employed by vascular ultrasonography (V-US), CT Angiography (CTA), MRI/A, and PET/CT without biopsy.

Methods:

We evaluated the clinical and serological characteristics of 20 patients who were diagnosed with GCA at our hospital from 2012 to 2018, and compared the image and biopsy findings of these patients. We then evaluated the effect of optimizing diagnostic imaging and methods for patients with suspected GCA who visited our hospital during 2019. Vascular mapping was carried out using V-US for 3DCTA and other imaging methods as references.

Results:

Table 1 shows the clinical characteristics of the study population. The sensitivity of CTA for GCA was 85.7% (12 of 14 patients), which was the highest of the studied imaging methods. All biopsy-positive cases were diagnosed as GCA, and we compared these cases with cases with positive imaging findings. This revealed that CTA findings were correct (i.e., positive) in 66.7% (four of six patients), MRI/A findings were correct in in 33.3% (three of nine), V-US findings were correct in 50.0% (three of six). Therefore, CTA exhibited the highest sensitivity for positive findings. Comparison of biopsy-positive cases with cases in which imaging findings were negative revealed that CTA findings were correct (negative) in 33.3% (two of six patients), MRI/A findings were correct in 55.6% (five of nine), V-US was correct in 50.0% (three of six). Thus, CTA had the lowest sensitivity for negative findings. Comparison of CTA findings of positive cases with other imaging modalities which reported positive findings revealed MRI/A findings to be correct in 44.4% (four of nine patients), PET/CT findings to be correct in 50.0% (one of two), V-US to be correct in 63.3% (five of eight). Thus, V-US had the highest agreement with CTA. We carried out vascular mapping by V-US using 3DCTA and other imaging methods and produced references to improve the accuracy of diagnosis. Using these references, we diagnosed five cases of GCA among the 20 patients; the positive predictive value of V-US was 80% (four of five patients) and negative predictive value was 86.7% (13 of 15 patients).

Table 1.

Baseline characteristics of the study sample

    

The number of biopsies performed decreased from 50% (10 of 20 patients) from 2012 to 2018 to 15% (3 of 20 patients) in 2019. Two cases in the present study had positive findings in both biopsy and V-US; in one case, biopsy, CTA, and MRI/A were negative while V-US revealed positive findings. No patients with GCA developed blindness or stroke during 2019.

Conclusion:

We propose that V-US should be performed as the first examination for the diagnosis of GCA by the creation of vascular mappings when GCA is suspected in order to prevent blindness and stroke.

References:

[1]Christian Dejaco et al.EULAR recommendations for the use of imaging in large vasculitis in clinical practice.Annals of the Rheumatic Diseases,2018 May;77(5):636-643

[2]Kawamoto T et al.Diagnosis of giant cell arthritis by head-contrast three-dimensional computed tomography angiography.Journal of Medical Case Reports2019 Sep 11;13(1):285.

Figure 1.

Left side is before, right side is after thrapy. (A) 3DCTA finding, (B) determination of V-US arrangement with vascular location to evaluate wall thickening of V-US, compression sign, stenosis and stoppage of vessels.

Disclosure of Interests:

None declared

THU0337 THE EFFECTIVENESS OF PLASMA EXCHANGE THERAPY FOR ANTI-MDA5 ANTIBODY-POSITIVE REFRACTORY INTERSTITIAL LUNG DISEASE

Background:

This is an extended report of our study [1]. Anti-melanoma differentiation-associated gene 5 (MDA5) antibodies, which are closely related to interstitial lung disease (ILD) with or without rapid progression, are a type of myositis-specific autoantibody. Since rapid progressive-ILD (RP-ILD) with anti-MDA5 antibodies is refractory and fatal, intensive immunosuppressive therapy with combination calcineurin inhibitor, and intravenous pulse cyclophosphamide was developed, and was shown to improve patient survival and prognosis [2]. However, 20–30% of cases were still fatal, and several additional therapies have been reported e.g. tofacitinib [3] and plasma exchange therapy (PE) [1, 4, 5].

Objectives:

We evaluated the effect of plasma exchange (PE) on survival in patients with refractory RP-ILD who were positive for anti-MDA5 antibodies.

Methods:

Among 167 patients newly diagnosed with PM/DM, clinically amyopathic DM, or cancer associated myositis from 2008 to 2019 at our hospital, 12 were diagnosed with refractory RP-ILD and were positive for anti-MDA5 antibodies. PE was used as an adjunct to standard therapy and consisted of fresh frozen plasma as replacement solution. The primary outcome was non-disease-specific mortality. anti-MDA5 antibody titres were measured by ELISA using the MESACUP anti-MDA5 test in 155 patients whose serum was frozen and stored at the time of diagnosis.

Results:

Anti-MDA5 antibodies were detected in 35 patients, of whom 26 were diagnosed with RP-ILD and 11 were refractory to intensive immunosuppressive therapy. Seven patients received PE (PE group) and four did not (non-PE group). The 1-year survival rate of the PE group was higher than that of the non-PE group (100% and 25%, respectively, P = 0.011). Regarding adverse events associated with PE, two patients had anaphylactic shock, one had high fever due to fresh frozen plasma allergy and one had a catheter infection. All adverse events resolved with appropriate treatment.

Conclusion:

We evaluated the association between 1-year survival rate and PE for refractory RP-ILD in patients positive for anti-MDA5 antibodies. Intensive immunosuppressive therapy improved the survival rate in RP-ILD patients with anti-MDA5 antibodies, but 20-30% of cases were still fatal. PE could be administered to patients with active infectious disease who were immunocompromised by intensive immunosuppressive therapy. PE may be considered in refractory RP-ILD patients positive for anti-MDA5 antibodies.

References:

[1]Nakashima R, Hosono Y, Mimori T. Clinical significance and new detection system of autoantibodies in myositis with interstitial lung disease. Lupus. 2016;25:925-33.

[2]Kurasawa K, Arai S, Namiki Y et al. Tofacitinib for refractory interstitial lung diseases in anti-melanoma differentiation-associated 5 gene antibody-positive dermatomyositis. Rheumatology. 2018;57:2114-9.

[3]Silveira MG, Selva-O’Callaghan A, Ramos-Terrades N et al. Anti-MDA5 dermatomyositis and progressive interstitial pneumonia. QJM. 2016;109:49-50.

[4]Endo Y, Koga T, Suzuki T et al. Successful treatment of plasma exchange for rapidly progressive interstitial lung disease with anti-MDA5 antibody-positive dermatomyositis: A case report. Medicine (Baltimore). 2018;97:e0436.

[5]Abe Y, Kusaoi M, Tada K et al. Successful treatment of anti-MDA5 antibody-positive refractory interstitial lung disease with plasma exchange therapy. Rheumatology. 2019.

Acknowledgments:

Funding: This work was supported by Japan Society for the Promotion of Science KAKENHI Grant Number JP18K15433.

Disclosure of Interests:

None declared

AB0422 LEFT VENTRICULAR ABNORMALITIES IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS FOLLOWED BY SEQUENTIAL ECHOCARDIOGRAPHY

Background:

Cardiovascular disease (CVD) is detected in up to 50% of systemic lupus erythematosus (SLE) patients1and major cause of death2. Even clinically silent SLE patients can develop left ventricular (LV) diastolic dysfunction3. Proper echocardiographic follow up of SLE patients is required.

Objectives:

To clarify how the prevalence of LV abnormalities changes over follow-up period and identify the associated clinical factors, useful in suspecting LV abnormalities.

Methods:

29 SLE patients (24 females and 5 men, mean age 52.8±16.3 years, mean disease duration 17.6±14.5 years) were enrolled. All of them underwent echocardiography as the baseline examination and reexamined over more than a year of follow-up period(mean 1075±480 days) from Jan 2014 to Sep 2019. Patients complicated with pulmonary artery hypertension, deep venous thrombosis or pulmonary embolism and underwent cardiac surgery during the follow-up period were excluded. Left ventricular(LV) systolic dysfunction was defined as ejection fraction (EF) < 50%. LV diastolic dysfunction was defined according to ASE/EACVI guideline4. LV dysfunction (LVD) includes one or both of LV systolic dysfunction and LV diastolic function. Monocyte to HDL ratio (MHR) was calculated by dividing monocyte count with HDL-C level.

Prevalence of left ventricular abnormalities was analysed at baseline and follow-up examination. Clinical characteristics and laboratory data were compared among patient groups as follows; patients with LV dysfunction (Group A) and without LV dysfunction (Group B) at the follow-up echocardiography, patients with LV asynergy at any point of examination (Group C) and patients free of LV abnormalities during the follow-up period (Group D).

Results:

At the baseline examination, LV dysfunction (5/29 cases, 13.8%), LV asynergy (6/29 cases, 21.7%) were detected. Pericarditis was detected in 7 patients (24.1%, LVD in 3 patients, LV asynergy in 2 patients) and 2 of them with subacute onset had progressive LV dysfunction, while 5 patients were normal in echocardiography after remission induction therapy for SLE. At the follow-up examination, LV dysfunction (9/29 cases, 31.0%, 5 new-onset and 1 improved case), LV asynergy (6/29 cases, 21.7%, 2 new-onset and 2 improved cases) were detected. Though any significant differences were observed between Group A and Group B at the baseline, platelet count (156.0 vs 207.0, p=0.049) were significantly lower in LV dysfunction group (Group A) at the follow-up examination. Group C patients had significantly higher uric acid (p=0.004), monocyte count (p=0.009), and MHR (p=0.003) than Group D(results in table).

Conclusion:

LV dysfunction is progressive in most of patients and requires regular follow-up once they developed. Uric acid, monocyte count and MHR are elevated in SLE patients with LV asynergy. Since MHR elevation was reported as useful marker of endothelial dysfunction5, our future goal is to analyse involvement of monocyte activation and endothelial dysfunction in LV asynergy of SLE patients.

References:

[1]Doria A et al. Lupus. 2005;14(9):683-6.

[2]Manger K et al. Ann Rheum Dis. 2002 Dec;61(12):1065-70.

[3]Leone P et al. Clin Exp Med. 2019 Dec 17.

[4]Nagueh SF et al. J Am Soc Echocardiogr. 2016 Apr;29(4):277-314.

[5]Acikgoz N et al. Angiology. 2018 Jan;69(1):65-70.

Numbers are median (interquartile range), Mann-Whitney u test were performed, p value less than 0.05 was considered statistically significant.

Disclosure of Interests: :

None declared

FRI0179 A STUDY ON THE ACHIEVEMENT OF LUPUS LOW DISEASE ACTIVITY STATE AND QUALITY OF LIFE IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: FROM THE JUNTENDO UNIVERSITY SLE PROSPECTIVE REGISTRY STUDY

Background:

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that affects mostly young women. Multiorgan complications and prolonged treatment significantly cause physical and mental stress in patients. Improving patients’ quality of life (QOL) in SLE treatment is essential. We examined the treatment effects on disease activity and QOL of SLE patients.

Objectives:

In recent years, lupus low disease activity state (LLDAS) has been proposed as a treatment target for SLE. Patients who achieve LLDAS have a low recurrence rate for lupus and a low risk of serious complications (1). The aim of this study is to investigate whether achieving LLDAS reduces not only recurrence rate and complications of SLE but also improves patients’ QOL.

Methods:

A total of 104 SLE patients were enrolled in our prospective SLE registry study (Juntendo, Multi-center, Prospective cohort for investigation of clinical course and outcome in SLE: JUMP) conducted at our institution. SLE was diagnosed using the American College of Rheumatology (ACR) 1982 criteria (revised in 1997). QOL was evaluated using the standard version of the 36-item short form health survey version 2 (SF36v2). Participants were divided into the LLDAS achievement and non-achievement groups, and the characteristics of each group including results of SF36v2 were examined.

Results:

This study included 104 SLE patients, 94 female and 10 male, and the average age and disease duration were 46.4±13.8 and 14.5±11.3 years, respectively. The average corticosteroid dose was 8.0±17.4 mg/day in terms of prednisolone, and anti-dsDNA antibody titer was 16.8±38.5 IU/ml. Of the 104 patients, 57 achieved LLDAS. The subscale’s standard scoring using SF36v2 for role physical (RP) was 78.9±24.0 and 64.6±27.6 (P<0.01), general health (GH) was 50.0±17.0 and 42.0±19.3 (P<0.05), vitality (VT) was 55.8±15.8 and 38.0±24.1 (P<0.01), social functioning (SF) was 82.0±20.7 and 66.5±26.3 (P<0.01), role emotional (RE) was 89.0±16.1 and 73.4±28.1 (P<0.01), and mental health (MH) was 72.4±15.9 and 58.3±21.8 (P<0.01) in the LLDAS achievement and non-achievement groups, respectively. Furthermore, scoring based on the national standard value in the LLDAS achievement group showed that two categories were >50. However, in the LLDAS non-achievement group, all categories were <50. In particular, RP, GH, VT, SF, RE, and MH of the LLDAS achievement group had significantly higher scores than the LLDAS non-achievement group (RP and GH: p<0.05 and VT, SF, RE and MH: p<0.01).

Conclusion:

Results of examining the association between LLDAS and QOL using SF36v2 in SLE patients showed that patients who achieved LLDAS had significantly better standard statistical scores in many subscale categories. Thus, LLDAS achievement as a treatment target for SLE patients greatly contributes to improving patients’ QOL.

References:

[1]Franklyn K, et al. Definition and initial validation of a Lupus Low Disease Activity State (LLDAS).Ann Rheum Dis. 2016 Sep;75(9):1615-21.

Disclosure of Interests:

None declared

P2716Correlation between computed tomography derived ischemia index and conventional fractional flow reserve

Background

Computed tomography (CT) derived ischemia index is a novel tool to determine the significance of coronary artery disease, however, its ability to identify myocardial ischemia has not been examined.

Methods

From Jan. 2013 to Dec. 2015, 14,000 patients underwent ECG-gated CT coronary angiography for suspected coronary artery disease. From Jan. 2013 to Jan. 2016, 483 patients (589 vessels) underwent conventional FFR to assess myocardial ischemia. Among those, FFR was assessed in 148 patients (167 vessels) within 30 days after CT coronary angiography. We further excluded 24 patients with prior stenting or bypass grafting, 3 patients with multiple MDCT or FFR, and 6 patients with insufficient datasets. Finally, we included 117 patients (127 vessels) to assess the correlation between CT derived ischemia index and conventional FFR.

CT derived ischemia index was calculated as follows: left ventricular volume distally to the coronary artery lumen (cm3)/coronary artery lumen area (mm2). Left ventricular volume was automatically determined using Advantage Workstation and divided according to the nearest coronary artery tree. Center of coronary arteries were manually traced and contours of coronary artery lumen were automatically depicted. CT derived ischemia index was calculated at approximately every 0.625mm point of coronary artery. Moving median of consecutive 5 points (approximately 3.125mm) were used to remove outliers. Maximum value of CT derived ischemia index per coronary artery segment was calculated to determine the significance of coronary artery disease.

Results

Mean age was 71.3±10.5 years and 63.8% of patients were male. Coronary angiography was performed to assess conventional FFR at the median of 13 days (IQR 7 to 18 days) after CT. Majority of the target vessel was left anterior descending artery (71.7%), followed by right coronary artery (14.2%), left circumflex artery (13.4%) and left main coronary artery (0.8%). According to the quantitative coronary angiography, minimum lumen diameter was 1.47±0.32mm with percent diameter stenosis of 48.3±10.4%. Median FFR value was 0.83 (IQR 0.76 to 0.88) and positive test for myocardial ischemia (FFR <0.80) was observed in 42 vessels (33.1%). Maximum CT derived ischemia index per segment ranged from 1.825 to 57.296 (median 8.333, IQR 4.911 to 14.484). There was a negative correlation between CT derived ischemia index and FFR (r=−0.319, 95% confidence interval −0.467 to −0.153, P<0.001). Receiver operating characteristic analysis indicated CT derived ischemia index of 9.962 has 76.2% sensitivity and 70.6% specificity for the presence of FFR<0.80 (AUC 0.73, 95% CI 0.64 to 0.82).

Conclusions

A novel tool of CT derived ischemia index has a significant negative correlation with conventional FFR in lesions with mild to moderate stenosis. Larger multicenter prospective studies are needed to fully determine the impact of CT derived ischemia index.

P3389Angioscopic differences in quality and quantity of neointima in patients experiencing an acute coronary syndrome treated with bare metal, first-, second-, and third generation drug-eluting stents

Background

Although drug-eluting stents (DES) have substantially reduced the need for early target lesion revascularization (TLR) compared with bare-metal stents (BMS) by inhibiting neointima hyperplasia, early generation DES have been associated with an increased risk of very late stent failure (VLSF) due to stent thrombosis and TLR after 1 year. Although the incidence of VLSF is reduced with newer generation DES, VLSF remains an unresolved problem and its mechanisms are not fully explored.

Purpose

The purpose of this study was to evaluate quality and quantity of neointima and presence of thrombus by using coronary angioscopy at long-term follow-up in patients who experienced an acute coronary syndrome (ACS) treated with BMS and DES on dual antiplatelet therapy.

Methods

Coronary angioscopy was performed at 6 and 10 months after BMS and DES implantation, respectively, in ACS patients. We assessed neointimal coverage (NC) of the stent struts, yellow color grade (YG) of stented segment and the existence of thrombus. Angioscopic NC was defined as follows: grade 0= fully visible struts; grade 1= visible struts through thin neointima; grade 2= no visible struts. We determined maximum (Max-NC) and minimum coverage (Min-NC) grades and the dominant NC grades. YG was classified into 4 grades (0= white; 1= slight yellow; 2= yellow; 3= intensive yellow). The obtained findings were compared with BMS, first-generation (1st-) DES, second-generation (2nd-) DES and third-generation (3rd-) DES.

Results

A total of 212 patients were enrolled: BMS (n=127), 1st DES (n=26, sirolimus-eluting stent), 2nd-DES (n=38, permanent polymer everolimus-eluting stent), and 3rd-DES (n=21, bioresorbable polymer everolimus-eluting stent). Max-NC and Min-NC grade were significantly lower with 1st- and 2nd-DES than with BMS and 3rd-DES (Figure). The same trend was also observed in the dominant NC grades. There was a lower trend of YG in BMS and 3rd-DES than in 1st or 2nd-DES (Figure). The presence of thrombus was significantly lower in 3rd-DES in comparison with BMS, 1st-, and 2nd-DES (3rd-DES 0%, BMS 20.5%, 1st-DES 24%, 2nd-DES 13.5%, P=0.01).

Figure 1

Conclusion

Patients treated with 3rd-DES have higher NC grade, lower incidence of intrastent thrombus, and lower YG than in 1st and 2nd-DES. These findings may explain the lower incidence of VLSF associated with these newer generation stent platforms.

P6544A real world study of high frequency atrial anti-tachycardia pacing in new algorithm for atrial arrhythmia

Background

Advanced pacemakers feature atrial antitachycardia pacing (aATP) therapies for terminating atrial arrhythmia. Previous studies showed the efficacy of combined atrial preventive pacing and aATP in patients with pacemakers. The independent effect of aATP and the impact for patients outside the clinical trials has not been well elucidated.

Methods

In a single center, prospective, all-comers trial, we enrolled 567 patients implanted cardiac devices with Reactive ATP function. History of permanent atrial fibrillation (AF) was not included. After device interrogation of the AF burden and the longest AF duration in the last 6 months, aATP was programmed as a bit more aggressive setting than MINERVA trial (time interval was set as every 2 hours). As for newly implanted devices, aATP was activated after at least 3 months run-in period. Primary and secondary outcomes were the longest AF duration and cumulative percentage of progression into permanent AF, respectively.

Results

Of 541 eligible patients, aged 75.3±10.7 years, 356 pacemaker, 82 ICD and 103 CRT patients, the longest single episode of AF lasted ≤6 min in 439 patients (81.1%), >6 min to 6 h in 43 (8.0%), >6–24 h in 33 (6.1%), and >24 h in 26 (4.8%) at the enrollment. During mean follow-up of 1.9 years, the longest AF episode lasted >24 h in 49 patients (9.1%) and 14 patients (2.6%) progressed into permanent AF. According with baseline longest single episode of AF, patients with AF ≤6 min developed an episode >24 h in 0.8% at 1 year and 3.2% at 2 years follow up; patients with AF >6 min to 6 h developed an episode >24 h in none at 1 year and 7% at 2 years follow up; and patients with AF >6–24 h developed an episode >24 h in 19% at 1 year and 42% at 2 years follow up, respectively. In a subgroup analysis of in 192 patients with at least 1 aATP, 46 patients with high efficacy (>44%) did not developed an episode >24 h. Only one patient developed into permanent AF without aATP therapy. On multivariate analysis, neither ICD nor CRT was independent risk factor for developing the longest AF episode >24 h.

Conclusions

The independent use of aATP without atrial preventive pacing was effective for preventing AF progression in a real world cohort. Even without the previous AF episodes, aATP could prevent AF development, especially in patients showing high aATP efficacy. Future research is required to enhance the aATP success rate.

EFFECT ON MICROBIAL PRODUCTS ON CAESIUM ELUTION BEHAVIOUR FROM CLAY MINERALS

Some microorganisms in the environment make siderophores, which are low molecular chelators, to take up minerals from soil. Eleven bacteria were separated from the root of white clover by chlome azrol S (CAS) assay. Each bacterium was incubated in casamino acid (CAA) culture, and siderophores in CAA culture were purified. These extractions were applied to biotite or vermiculite spiked with Cs. From each clay mineral, 57.1-72.8% (5100 ppm), 55.6-63.8% (920 ppm) and 48.6-54.3% (2300 ppm), 31.6-34.4% (520 ppm) was eluted, respectively. To understand elution behaviour, Cs desorption ratio of each clay was measured every 30 min. The results indicate Cs elution was occurred quickly.

Oxygen surface exchange properties and surface segregation behavior of nanostructured La0.6Sr0.4Co0.2Fe0.8O3-δ thin film cathodes

Cathode materials with highly reactive surfaces and long-term stability are required to achieve high-performance solid oxide fuel cells (SOFCs). In this study, a promising cathode material, La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), was prepared as a nanostructured thin film using pulsed laser deposition (PLD) on gadolinia-doped ceria (GDC)-buffered YSZ single crystal substrates having (100) and (111) orientations. Characterization revealed intrinsic differences among the as-grown LSCF thin films in terms of dominant crystalline orientation and nanostructure depending on GDC preparation as well as the YSZ substrate orientation. Evaluation of the oxygen exchange properties using the isotope exchange depth profile method revealed that LSCF thin films grown on (111) GDC/YSZ exhibited higher values of the apparent surface exchange coefficient compared to LSCF thin films grown on (100) GDC/YSZ. However, when subjected to long-term annealing at high temperatures, the former exhibited a stronger tendency to surface segregation as compared to the latter. These behaviors are correlated with the intrinsic properties of LSCF thin films, including the nanostructure, the possible effects attributed to SrO activity, and the stability of perovskite surfaces which would drive surface segregation. These results have implications for tailoring the performance of cathode thin films by understanding the dependence of oxygen exchange properties and surface segregation on driving forces such as surface chemistry and nanostructure.

Bifidobacterium bifidum YIT 10347 fermented milk exerts beneficial effects on gastrointestinal discomfort and symptoms in healthy adults: A double-blind, randomized, placebo-controlled study

In a preliminary open-label trial by our group, Bifidobacterium bifidum YIT 10347 (YIT10347) relieved gastric symptoms in patients with functional gastrointestinal disorders. Hence, in this study, we investigated the effects of YIT10347 on gastrointestinal symptoms in healthy adults. In this prospective double-blind, randomized, placebo-controlled trial (UMIN000024654), 100 healthy Japanese adults were randomly assigned to a YIT10347 group or placebo group and consumed 100 mL of YIT10347-fermented milk or placebo fermented milk, respectively, every day for 4 wk. Gastrointestinal symptoms were evaluated by using the modified Frequency Scale for Symptoms of Gastroesophageal Reflux Disease (m-FSSG) and Gastrointestinal Symptom Rating Scale (GSRS) as primary endpoints. Mental symptoms, quality of life, salivary stress markers, and gastric emptying were evaluated as secondary endpoints. Effectiveness and safety were analyzed in a per-protocol set (YIT10347 group, n = 39; placebo group, n = 40) and full analysis set (YIT10347 group, n = 50; placebo group, n = 50), respectively. In the m-FSSG evaluation, the YIT10347 group had a significantly higher relief rate of postprandial discomfort and greater changes in postprandial epigastric pain score from baseline than the placebo group. In the GSRS evaluation, the YIT10347 group had significantly higher relief rates of overall gastrointestinal symptoms, upper gastrointestinal symptoms, flatus, and diarrhea than the placebo group. We detected no significant differences in scores or relief rates of mental symptoms and quality of life, a salivary stress marker, or gastric emptying between the 2 groups. No severe adverse events associated with test beverage consumption were observed in either group. These findings suggest that daily consumption of YIT10347-fermented milk exerts beneficial effects on gastrointestinal discomfort and symptoms such as postprandial discomfort and epigastric pain in healthy adults.

Haemaphysalis longicornis tick bites are a possible cause of red meat allergy in Japan

Recent studies revealed that Amblyomma or Ixodes tick bites may cause red meat allergy, in which galactose-α-1,3-galactose (α-Gal) is a major IgE-binding epitope. The incidence of red meat allergy is high in Shimane Prefecture, as is tick-transmitted Japanese spotted fever. Therefore, we speculated that tick bites may cause these meat allergies. The carbohydrate α-Gal was detected in the salivary gland protein of Haemaphysalis longicornis (H. longicornis), the vector for Japanese spotted fever, by immunoblotting using anti-α-Gal antibody. H. longicornis salivary gland protein-specific IgE was detected in the sera of 24 of 30 patients with red meat allergies. Sensitization to tick salivary gland protein containing α-Gal is possibly a major etiology of red meat allergy; the carbohydrate plays a crucial role in its allergenicity. These results further indicate that the α-Gal epitope is present not only in Amblyomma or Ixodes, but also in Haemaphysalis.

Direct evidence for susceptibility genes for type 2 diabetes on mouse chromosomes 11 and 14

AIMS/HYPOTHESIS

Diabetogenic loci for type 2 diabetes have been mapped to mouse chromosome (Chr) 11 and 14 in the Nagoya-Shibata-Yasuda (NSY) mouse, an animal model of type 2 diabetes. We aimed to obtain direct evidence of these genes on each chromosome and to clarify their function and interaction in conferring susceptibility to type 2 diabetes.

METHODS

We established three consomic strains homozygous for diabetogenic NSY-Chr11, NSY-Chr14 or both on the control C3H background (C3H-11(NSY), C3H-14(NSY) and C3H-11(NSY)14(NSY), respectively), and monitored diabetes-related phenotypes longitudinally. The glucokinase gene was sequenced as a positional candidate gene on Chr11.

RESULTS

C3H-11(NSY) mice showed hyperglycaemia associated with impaired insulin secretion and age-dependent insulin resistance without obesity. C3H-14(NSY) mice exhibited hyperglycaemia mainly due to insulin resistance, with a slight increase in percentage body fat. C3H-11(NSY)14(NSY) double consomic mice showed marked hyperglycaemia and obesity, which was not observed in single consomic strains. Sequences of the glucokinase gene were allelically variant between NSY and C3H mice.

CONCLUSIONS/INTERPRETATION

These data provide direct evidence that Chr11 and Chr14 harbour major susceptibility genes for type 2 diabetes. These two chromosomes interact to cause more severe hyperglycaemia and obesity, which was not observed with the presence of either single chromosome, indicating different modes of gene-gene interaction depending on the phenotype. Marked changes in the phenotypes retained in the consomic strains will facilitate fine mapping and the identification of the responsible genes and their interaction with each other, other genes and environmental factors.