AB0592 IS IT TIME TO DISSECTING GIANT CELL ARTERITIS INTO SUBPHENOTYPES? A CLOSE LOOK TO DATA OF EASTERN MEDITERRANEAN VASCULITIS CENTRE

Background

Patients with giant cell arteritis (GCA) have heterogeneity in terms of not only symptoms and findings but also extent of arterial involvement. In era of personalized medicine, therapy of patients is based on these diverse parameters.

Objectives

This study is aimed to identify subphenotypes of GCA, treatments have been used and outcomes in a prospective database of Eastern Mediterranean Vasculitis Centre.

Methods

Among 2454 patients recorded into Hacettepe University Vasculitis Research Centre database since October 2014; 181 of them were Takayasu’s arteritis and 89 of them GCA. 17 GCA patients were excluded due to missing data. Patients were grouped as Cranial GCA, Cranial GCA+ PMR, Cranial and LV GCA + PMR, Cranial and LV GCA, and LV GCA.

Demographic and clinical findings, histopathological and imaging data as well as outcome was collated for each subphenotype.

Results

Of 72 patients enrolled into further analysis, a female predominance (72.2%) was observed with mean age at diagnosis of 68.3(±8.2) years. Seventy-four percent of patients had cranial GCA (Figure 1) and leading subphenotype of all patients was only cranial GCA. Usage of temporal artery biopsy (TAB), temporal artery and axillary artery ultrasonography, and imaging modalities were different according to phenotypes of GCA.

Figure 1.

Distribution of GCA subphenotypes

Of the 38 patients having TAB, 20(42.9%) were consisted with GCA. The main histopathological finding were inflammation rich in lymphohistiocytic cells in the temporal artery (44.7%) and fragmentation and loss of integrity of the internal elastic lamina (36.8%).

All of the patients have been used corticosteroids with a median starting dose of 16 mg/day(8-64) had used pulse therapy. Any of conventional DMARDS (AZA, MTX, LEF, CYC) have been used in 60 of patients. In all cases, Tocilizumab was recommended after resistant/intolerant to conventional DMARDs (n=6).

Follow-up data was based on 64 patients. During a median 5,8 (±4.0) years follow-up, 6 (9.3%) patients deceased. Thirteen (20.3%) had one and more relapses, 8(61.5%) from isolated GCA group and 4(30.7%) from Only LV GCA group.

Conclusion

GCA is less frequent than TAK in our centre. Female predominance and a seventh decade of disease onset was observed in our cohort. Heterogeneity of disease was observed in or cohort along with different frequently used diagnostic confirmatory modality among subphenotypes. Relapse rate was 20 percent during a 6-year follow up with a 83% additional DMARD usage.

References

[1]K. Bates Gribbons1, Peter C Grayson1, et al Diagnostic Assessment Strategies and Disease Subsets in Giant Cell Arteritis: Data From an International Observational Cohort, Arthritis Rheumatology, 2020 Apr;72

Table 1.

Confirmatory modality of GCA diagnosis and treatments of subphenotypes

Only cranial GCA(n=38)Cranial GCA+PMR(n=6)Cranial GCA+LV GCA+ PMR(n=2)Cranial+LV GCA(n=5)LV GCA+PMR (n=7)Only LV GCA (n=14)Diagnosed confirmed by TAB(Total n=26)2042Temporal ultrasonography(Total n=24)182121PET CT/Vasculitis MR/VasculitisBT (Total n=22)13612Only steroidn=126213Pulse steroidn=148114Methotrexaten=351722167Leflunomiden=321Azatioprinen=19122113Cyclophosphamiden=11Tosilizumabn=862

Disclosure of Interests

None declared

Effects of mitral annular calcification on the outcomes of transcatheter aortic valve implantation

Background

Transcatheter aortic valve implantation (TAVI) has become the standard of care treatment in patients with severe aortic stenosis who carry intermediate or high risk for surgical aortic valve replacement. Mitral annular calcification (MAC) is frequently seen in patients with aortic stenosis and it is associated with increased cardiovascular morbidity and mortality. It is reported that MAC is an independent predictor of all cause mortality after TAVI.

Aim

The aim of this study is to both evaluate the relationship between mitral annular calcification and TAVI related complications and mortality; and to define the predictors of both all cause mortality and permanent pacemaker implantation after TAVI.

Methods

All of the patients who underwent TAVI procedure due to severe aortic stenosis between 01.01.2020 and 01.06.2020 in our University Hospital were screened and patients fullfilling including criterias were enrolled. Patients' baseline demographic datas, laboratory, echocardiography and TAVI procedure related parameters were recorded. Outcomes are identified as follows; association between mitral annular calcification and TAVI related complications, establishment of the predictors of all cause mortality and permanent pacemaker implantation, definition of the in-hospital and all cause mortality rates.

Results

A total of 245 patients including 98 males (40%) and 147 females (60%) were enrolled in the study. The mean age of the population was 76,3±8,3 years. The mean left ventricular ejection fraction was % 54,8±11,4; aortic valve area was 0,74±0,14 cm2 and mean aortic transvalvular gradient was 47,0±14,3 mmHg. MAC was detected in 148 (% 60,4) patients (Table 1). In-hospital mortality was occurred in 14 (5,7%) cases. Permanent pacemaker implantation was performed in %17,8 (n=42) patients and all cause mortality was developed in 89 (36,3%) cases during the median 23,1 (11,6–44,3) months follow-up. Pericardial effusion (26,4% vs 12,4%; p=0,013) and contrast induced nephropathy (21,6% vs 7,2%; p=0,005) were developed more frequently in patients with MAC than without MAC (Table-2). Only the presence of MAC extending to left ventricular outflow tract was detected to be independent predictor of permanent pacemaker implantation requirement (HR: 3,32; p=0,002). All cause mortality predictors were established as; use of renin-angiotensin-aldosterone system blockers (HR: p=0,012), level of hemoglobin (HR: 0,79; p=0,006), severe mitral annular calcification (HR: 1,94; p=0,024) and atrial fibrillation development after TAVI (HR: 2,39; p=0,002). There was not any correlation between aortic valve area and MAC vloume (r=0,03; p=0,689), MAC Hounsfield Unit (r=−0,007; p=0,934) and MAC Agatston score (r=−0,08; p=0,290).

Discussion

MAC is associated with all cause mortality after TAVI and MAC extending to left ventricular outflow tract is an independent predictor of permanent pacemaker implantation requirement.

Funding Acknowledgement

Type of funding sources: None.

The effect of barrier layers on 2D electron effective mass in Al0.3Ga0.7N/AlN/GaN heterostructures

The Shubnikov de Haas (SdH) effect measurements have been performed to evaluate the influence of Si₃N₄passivation, a spacer layer, and Si-doped barrier layer on the electronic transport parameters of two-dimensional (2D) electrons in Al_0.3Ga_0.7N/AlN/GaN heterostructures under temperatures from 1.8 K to 40 K and at a magnetic field up to 11 T. The 2D electron effective mass (m*), 2D carrier density (N_2D), the difference between Fermi level and subband energy levels (E_F-E₁), quantum lifetime (τ_q) are determined by analyzing SdH oscillations. Although investigated samples with equal 2D electron density are examined, the effective mass values of 2D electrons are deduced within the range of (0.16 ± 0.005)m₀and (0.23 ± 0.005)m₀. Results reveal that passivation, a spacer layer, and doping affect 2D electron effective mass. Furthermore, the dominant scattering mechanisms that limited electron transport is determined as a long-range scattering for all investigated sample. The results obtained provide information for the high-performance device application of these samples.