Prospective long term follow-up of a cohort of patients with giant cell arteritis screened for aortic structural damage (aneurysm or dilatation)

EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice summary

Large vessel vasculitis (LVV) is the most common form of primary vasculitis comprising of giant cell arteritis (GCA), Takayasu's arteritis (TAK) and idiopathic aortitis. Early diagnosis and treatment of LVV are paramount to reduce the risk of ischemic complications such as visual loss and strokes, vascular stenosis and occlusion, and aortic aneurysm formation. Use of imaging modalities [ultrasound (US), magnetic resonance imaging (MRI), computed tomography (CT) and [18F]-fluorodeoxyglucose positron emission tomography (PET)] has steadily increased to enable assessment of cranial and extracranial arteries, as well as the aorta. These imaging modalities are less invasive, more sensitive and readily available compared to temporal artery biopsy (TAB). Modern imaging methods have changed the role of TAB in diagnosing GCA and have replaced diagnostic angiography. Over the last two decades, several studies have evaluated the use of US, MRI, CT and PET in LVV. However, these various imaging tools are not yet uniformly used in routine clinical practice and controversy exists as to which imaging modality best provides meaningful assessments of disease activity and damage in LVV. In January 2018, evidence-based recommendations for the use of imaging modalities in LVV were published. The aim of this review is to summarize the current evidence of imaging in patients with or suspected of having LVV, and to highlight the clinical implications of the EULAR recommendations.

Large-vessel vasculitis diagnosed between 50 and 60 years: Case-control study based on 183 cases and 183 controls aged over 60 years

BACKGROUND

Age at onset of large-vessel vasculitis (LVV) is commonly used to distinguish giant cell arteritis (GCA) and Takayasu arteritis (TA). However, LVV between age 50 and 60 years may be difficult to classify.

METHODS

We conducted a retrospective study including LVV aged between 50 and 60 years at onset (LVV_50-60, cases) and compared them to LVV aged over 60 years (LVV_>60, controls). LVV was defined histologically and/or morphologically. Controls fulfilled ACR 1990 criteria for GCA or presented isolated aortitis.

RESULTS

We included 183 LVV_50-60 and 183 gender-matched LVV_>60. LVV_50-60 had more frequent peripheral limb manifestations (23 vs. 5%), and less frequent cephalic (73 vs. 90%) and ocular signs (17 vs. 27%) than LVV_>60. Compared to LVV_>60, CT angiography and PET/CT scan were more frequently abnormal in LVV_50-60 (74 vs. 38%, and 90 vs. 72%, respectively), with aorta being more frequently involved (78 vs. 47%). By multivariate analysis, absence of cephalic symptoms, presence of peripheral limb ischemia and aorta involvement, and increased CRP level were significantly associated with LVV_50-60 presentation compared to LVV_>60. At last follow-up, compared to LVV_>60, LVV_50-60 received significantly more lines of treatment (2 vs. 1), more frequent biologics (12 vs. 3%), had more surgery (10 vs. 0%), and had higher prednisone dose (8.8 vs. 6.5 mg/d) at last follow-up, CONCLUSION: LVV onset between 50 and 60 years identifies a subset of patients with more frequent aorta and peripheral vascular involvement and more refractory disease compared to patients with LVV onset after 60.

Diagnosis and management of giant cell arteritis: an Asia-Pacific perspective

Giant cell arteritis is the commonest primary vasculitis of the elderly. However, the prevalence does vary widely between populations with highest incidence amongst Northern Europeans and lowest amongst East Asians. Preliminary studies suggest that clinical manifestations may differ between different populations. Newer diagnostic approaches including ultrasound, MR angiography and PET imaging are under review. While there have been recent advances in the diagnosis of GCA particularly with regard to imaging, there is an urgent need for improvements in methods of diagnosis, treatment and requirement for screening. Glucocorticoid treatment remain the backbone of therapy. However, glucocorticoid therapy is associated with significant adverse effects. Conventional and novel immunosuppressive agents have only demonstrated modest effects in a subgroup of steroid refractory GCA due to the different arms of the immune system at play. However, recently a study of IL-6 blockade demonstrated benefit in GCA. Newer approaches such as fast-track pathways can also result in improvements in consequences of GCA including blindness.

Tocilizumab as an add-on therapy to glucocorticoids during the first 3 months of treatment of Giant cell arteritis: A prospective study

BACKGROUND

The aim of this study was to evaluate tocilizumab (TCZ) as an add-on therapy to glucocorticoids (GC) during the first 3 months of treatment of giant cell arteritis (GCA).

METHODS

GCA patients, as defined by ≥3/5 ACR criteria and positive temporal artery biopsy (TAB) or angio-CT-scan or PET-scan-proven aortitis, were included in this prospective open-label study. Prednisone was started at 0.7 mg/kg/day and then tapered according to a standardized protocol. All patients received four infusions of TCZ (8 mg/kg/4 weeks) after inclusion. The primary endpoint was the percentage of patients in remission with ≤0.1 mg/kg/day of prednisone at week 26 (W26). Patients were followed for 52 weeks and data prospectively recorded.

RESULTS

Twenty patients with a median (IQR) age of 72 (69-78) years were included. TAB were positive in 17/19 (90%) patients and 7/16 (44%) had aortitis. Remission was obtained in all cases. At W26, 15 (75%) patients met the primary endpoint. Ten patients experienced relapse during follow-up, mainly patients with aortitis (P = 0.048), or CRP >70 mg/L (P = 0.036) or hemoglobin ≤10 g/dL (P = 0.015) at diagnosis. Among 64 adverse events (AE) reported in 18 patients, three were severe and 30, mostly non-severe infections (n = 15) and hypercholesterolemia (n = 8), were imputable to the study.

CONCLUSION

This study shows that an alternative strategy using a short-term treatment with TCZ can be proposed to spare GC for the treatment of GCA. However, 50% of patients experienced relapse during the 9 months following TCZ discontinuation, especially patients with aortitis, or CRP > 70 mg/L or Hb ≤ 10 g/dL at diagnosis.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01910038).

Aortic dilatation in patients with large vessel vasculitis: A longitudinal case control study using PET/CT

OBJECTIVE

To evaluate aortic diameter and predictors of aortic dilatation using ¹⁸FDG-PET/CT in a longitudinally followed cohort of patients with large vessel vasculitis (LVV) compared with controls.

METHODS

All consecutive patients with LVV who underwent at least 2 PET/CT scans between January 2008 and May 2015 were included. The first and last PET/CT study was evaluated by a radiologist and a nuclear medicine physician. Diameter and FDG uptake of the aorta was measured at 4 different levels: ascending, descending thoracic, suprarenal and infrarenal abdominal aorta. Twenty-nine age- and sex-matched patients with lymphoma who underwent at least 2 PET/CT scans in the same time interval were selected as controls.

RESULTS

93 patients with LVV were included in the study. In the time interval between first and last PET/CT study (median time 31 months), the diameter of the ascending, descending thoracic and suprarenal abdominal aorta significantly increased in LVV patients but not in controls. At last PET/CT, patients with LVV compared with controls had higher diameter of ascending [35.41 (5.54) vs 32.97 (4.11) mm, p = 0.029], descending thoracic [28.42 (4.82) vs 25.72 (3.55) mm, p = 0.007] and suprarenal abdominal aorta, mean [25.34 (7.01) vs 22.16 (3.26) mm, p = 0.005] and more frequently had aortic dilatation [19% vs 3%, p = 0.023]. Significant predictors of aortic dilatation were male sex [OR 7.27, p = 0.001] and, only for GCA, hypertension [OR 6.30, p = 0.031]. Finally, GCA patients with aortic FDG uptake grade 3 at first PET/CT, compared to those with aortic FDG uptake ≤2, had significantly higher aortic diameter.

CONCLUSIONS

Patients with LVV are at increased risk of aortic dilatation compared with age- and sex-matched controls. Significant predictors of aortic dilatation are male sex and, only for GCA, hypertension. GCA patients with aortic FDG uptake grade 3 are at increased risk of aortic dilatation.

Investigations in systemic vasculitis - The role of imaging

Imaging plays an increasing role for confirming a suspected diagnosis of giant cell arteritis (GCA) or Takayasu arteritis (TAK). Ultrasound, magnetic resonance imaging (MRI), and computed tomography demonstrate a homogeneous, most commonly concentric, arterial wall thickening. 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) displays increased FDG uptake of inflamed artery walls delineating increased metabolism. Ultrasound and MRI are recommended to be the initial imaging modalities in cranial GCA and TAK, respectively. Extracranial disease can be confirmed by all four modalities, particularly by PET in case of inflammation of unknown origin. If the diagnosis remains uncertain, additional investigations including biopsy and/or additional imaging are recommended. Imaging should be performed by a trained specialist using appropriate operational procedures and settings with appropriate equipment. Further research is necessary on the role of imaging for disease monitoring. This review will discuss advantages and disadvantages of imaging modalities in the diagnosis of vasculitis.

Pathogenesis of giant-cell arteritis: how targeted therapies are influencing our understanding of the mechanisms involved

GCA is a chronic granulomatous vasculitis that affects large- and medium-sized vessels. Both the innate and the adaptive immune system are thought to play an important role in the initial events of the pathogenesis of GCA. Amplification cascades are involved in the subsequent development and progression of the disease, resulting in vascular inflammation, remodelling and occlusion. The development of large-vessel vasculitis in genetically modified mice has provided some evidence regarding potential mechanisms that lead to vascular inflammation. However, the participation of specific mechanistic pathways in GCA has not been fully established because of the paucity and limitations of functional models. Treatment of GCA is evolving, and novel therapies are being incorporated into the GCA treatment landscape. In addition, to improve the management of GCA, targeted therapies are providing functional proof of concept of the relevance of particular pathogenic mechanisms in the development of GCA and in sustaining vascular inflammation.

Large-vessel giant cell arteritis: diagnosis, monitoring and management

GCA is a chronic, idiopathic, granulomatous vasculitis of medium and large arteries. It comprises overlapping phenotypes including classic cranial arteritis and extra-cranial GCA, otherwise termed large-vessel GCA (LV-GCA). Vascular complications associated with LV-GCA may be due, in part, to delayed diagnosis, highlighting the importance of early identification and prompt initiation of effective therapy. Advancements in imaging techniques, including magnetic resonance angiography, CT angiography, PET and colour duplex ultrasonography, have led to improvements in the diagnosis of LV-GCA; however, the role imaging modalities play in the assessment of disease activity and long-term outcomes remains unclear. Glucocorticoids are the mainstay of therapy in LV-GCA, but their prolonged use is associated with multiple, sometimes serious, adverse effects. Recent data suggest that biologic therapies, such as tocilizumab, may be effective and safe steroid-sparing options for patients with GCA. However, data specifically evaluating the management of LV-GCA are limited.

Giant cell arteritis: beyond temporal artery biopsy and steroids

Giant cell arteritis is the most common primary vasculitis of the elderly. The acute complications of untreated giant cell arteritis, such as vision loss or occasionally stroke, can be devastating. The diagnosis is, however, not altogether straightforward due to variable sensitivities of the temporal artery biopsy as a reference diagnostic test. In this review, we discuss the increasing role of imaging in the diagnosis of giant cell arteritis. Glucocorticoid treatment is the backbone of therapy, but it is associated with significant adverse effects. A less toxic alternative is required. Conventional and novel immunosuppressive agents have only demonstrated modest effects in a subgroup of steroid refractory Giant cell arteritis due to the different arms of the immune system at play. However, recently a study of interleukin-6 blockade demonstrated benefits of giant cell arteritis. The current status of these immunosuppressive agents and novel therapies are also discussed in this review.

Arterial lesions in giant cell arteritis: A longitudinal study

OBJECTIVES

To evaluate large-vessel (LV) abnormalities on serial imaging in patients with giant cell arteritis (GCA) and discern predictors of new lesions.

METHODS

Clinical and imaging data from patients with GCA (including subjects diagnosed by LV imaging) enrolled in a prospective, multicenter, longitudinal study and/or a randomized clinical trial were included. New arterial lesions were defined as a lesion in a previously unaffected artery.

RESULTS

The study included 187 patients with GCA, 146 (78%) female, mean (±SD) age at diagnosis 68.5 ± 8.5 years; 39% diagnosed by LV imaging. At least one arterial lesion was present in 123 (66%) on the first study. The most frequently affected arteries were subclavian (42%), axillary (32%), and thoracic aorta (20%). In 106 patients (57%) with serial imaging, new arterial lesions were noted in 41 patients (39%), all of whom had a baseline abnormality, over a mean (±SD) follow-up of 4.39 (2.22) years. New abnormalities were observed in 33% patients by year 2; clinical features of active disease were present at only 50% of these cases. There were no differences in age, sex, temporal artery biopsy positivity, or disease activity in patients with or without new lesions.

CONCLUSIONS

In this cohort of patients with GCA, LV abnormalities on first imaging were common. Development of new arterial lesions occurred in patients with arterial abnormalities at first imaging, often in the absence of symptoms of active disease. Arterial imaging should be considered in all patients with GCA at diagnosis and serial imaging at least in patients with baseline abnormalities.

EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice

To develop evidence-based recommendations for the use of imaging modalities in primary large vessel vasculitis (LVV) including giant cell arteritis (GCA) and Takayasu arteritis (TAK). European League Against Rheumatism (EULAR) standardised operating procedures were followed. A systematic literature review was conducted to retrieve data on the role of imaging modalities including ultrasound, MRI, CT and [18F]-fluorodeoxyglucose positron emission tomography (PET) in LVV. Based on evidence and expert opinion, the task force consisting of 20 physicians, healthcare professionals and patients from 10 EULAR countries developed recommendations, with consensus obtained through voting. The final level of agreement was voted anonymously. A total of 12 recommendations have been formulated. The task force recommends an early imaging test in patients with suspected LVV, with ultrasound and MRI being the first choices in GCA and TAK, respectively. CT or PET may be used alternatively. In case the diagnosis is still in question after clinical examination and imaging, additional investigations including temporal artery biopsy and/or additional imaging are required. In patients with a suspected flare, imaging might help to better assess disease activity. The frequency and choice of imaging modalities for long-term monitoring of structural damage remains an individual decision; close monitoring for aortic aneurysms should be conducted in patients at risk for this complication. All imaging should be performed by a trained specialist using appropriate operational procedures and settings. These are the first EULAR recommendations providing up-to-date guidance for the role of imaging in the diagnosis and monitoring of patients with (suspected) LVV.

CT analysis of the aorta in giant-cell arteritis: a case-control study

OBJECTIVES

Giant cell arteritis (GCA) is a large-vessel vasculitis whose diagnosis is confirmed by temporal artery biopsy. However, involvement of large vessels, especially the aorta, can be shown by imaging, which plays an increasing role in GCA diagnosis. The threshold above which aortic wall thickening, as measured by computed tomography (CT), is considered pathological is controversial, with values ranging from 2 to 3 mm. This study assessed aortic morphology by CT scan and its diagnostic value in GCA.

METHODS

Altogether, 174 patients were included (64 with GCA, 43 with polymyalgia rheumatica and 67 controls). All patients had a CT scan at diagnosis or at inclusion for controls. Aortic wall thickness, aortic diameter and scores for atheroma were measured. Assessor was blinded to each patient's group.

RESULTS

Aortic diameters and atheroma scores were similar between groups. Aortic wall thickness was greater in the GCA group, even after the exclusion of GCA patients with aortic wall thickness ≥3 mm. The receiver operating characteristic (ROC) curve showed that a wall thickness of 2.2 mm was the optimal threshold to diagnose GCA (sensitivity, 67%; specificity, 98%).

CONCLUSIONS

Measuring aortic wall thickness by CT scan is effective to diagnose GCA. The optimal threshold to regard aortic wall thickening as pathological was ≥2.2 mm.

KEY POINTS

• Imaging, including CT scan, plays an increasing role in GCA diagnosis • CT measurement of aortic wall thickness is useful to diagnose GCA • A 2.2-mm threshold allows the diagnosis of thickened aortic wall in GCA.

Imaging in diagnosis, outcome prediction and monitoring of large vessel vasculitis: a systematic literature review and meta-analysis informing the EULAR recommendations

Objectives

To perform a systematic literature review on imaging techniques for diagnosis, outcome prediction and disease monitoring in large vessel vasculitis (LVV) informing the European League Against Rheumatism recommendations for imaging in LVV.

Methods

Systematic literature review (until 10 March 2017) of diagnostic and prognostic studies enrolling >20 patients and investigating ultrasound, MRI, CT or positron emission tomography (PET) in patients with suspected and/or established primary LVV. Meta-analyses were conducted, whenever possible, obtaining pooled estimates for sensitivity and specificity by fitting random effects models.

Results

Forty-three studies were included (39 on giant cell arteritis (GCA), 4 on Takayasu arteritis (TAK)). Ultrasound ('halo' sign) at temporal arteries (8 studies, 605 patients) and MRI of cranial arteries (6 studies, 509 patients) yielded pooled sensitivities of 77% (95% CI 62% to 87%) and 73% (95% CI 57% to 85%), respectively, compared with a clinical diagnosis of GCA. Corresponding specificities were 96% (95% CI 85% to 99%) and 88% (95% CI 81% to 92%). Two studies (93 patients) investigating PET for GCA diagnosis reported sensitivities of 67%-77% and specificities of 66%-100% as compared with clinical diagnosis or temporal artery biopsy. In TAK, one study each evaluated the role of magnetic resonance angiography and CT angiography for diagnostic purposes revealing both a sensitivity and specificity of 100%. Studies on outcome prediction and monitoring disease activity/damage were limited and mainly descriptive.

Conclusions

Ultrasound and MRI provide a high diagnostic value for cranial GCA. More data on the role of imaging for diagnosis of extracranial large vessel GCA and TAK, as well as for outcome prediction and monitoring in LVV are warranted.

Serum osteopontin: a biomarker of disease activity and predictor of relapsing course in patients with giant cell arteritis. Potential clinical usefulness in tocilizumab-treated patients

Background

Osteopontin (OPN) is a glycoprotein involved in Th1 and Th17 differentiation, tissue inflammation and remodelling. We explored the role of serum OPN (sOPN) as a biomarker in patients with giant cell arteritis (GCA).

Methods

sOPN was measured by immunoassay in 76 treatment-naïve patients with GCA and 25 age-matched and sex-matched controls. In 36 patients, a second measurement was performed after 1 year of glucocorticoid treatment. Baseline clinical and laboratory findings, as well as relapses and glucocorticoid requirements during follow-up, were prospectively recorded. sOPN and C reactive protein (CRP) were measured in 32 additional patients in remission treated with glucocorticoids or tocilizumab (interleukin 6 (IL-6) receptor antagonist). In cultured temporal arteries exposed and unexposed to tocilizumab, OPN mRNA expression and protein production were measured by reverse transcription polymerase chain reaction (RT-PCR) and immunoassay, respectively.

Results

sOPN concentration (ng/mL; mean±SD) was significantly elevated in patients with active disease (116.75±65.61) compared with controls (41.10±22.65; p<0.001). A significant decline in sOPN was observed in paired samples as patients entered disease remission (active disease 102.45±57.72, remission 46.47±23.49; p<0.001). sOPN correlated with serum IL-6 (r=0.55; p<0.001). Baseline sOPN concentrations were significantly higher in relapsing versus non-relapsing patients (relapsers 129.08±74.24, non-relapsers 90.63±41.02; p=0.03). OPN mRNA expression and protein production in cultured arteries were not significantly modified by tocilizumab. In tocilizumab-treated patients, CRP became undetectable, whereas sOPN was similar in patients in tocilizumab-maintained (51.91±36.25) or glucocorticoid-maintained remission (50.65±23.59; p=0.49).

Conclusions

sOPN is a marker of disease activity and a predictor of relapse in GCA. Since OPN is not exclusively IL-6-dependent, sOPN might be a suitable disease activity biomarker in tocilizumab-treated patients.

Classification of large vessel vasculitis: Can we separate giant cell arteritis from Takayasu arteritis?

The two main variants of large vessel vasculitis include Takayasu arteritis and giant cell arteritis. While these two conditions have historically been considered different conditions, recent evidence questions whether they are a spectrum of the same disease. Classification criteria are limited in distinguishing between cases with phenotypic overlap. The limitations of the current criteria and directions of future research are reviewed.

Predictors of Dissection in Aortic Aneurysms From Giant Cell Arteritis

BACKGROUND

Factors associated with dissection from inflammatory aortic aneurysms may be different from those in the general population.

OBJECTIVE

The aim of this study was to evaluate the risk factors for aortic dissection/rupture in patients with giant cell arteritis (GCA) and aortic aneurysms.

METHODS

A population-based incident cohort of patients with a diagnosis of GCA from 1950 to 2004 was used. All patients with aortic aneurysms diagnosed 1 year prior to GCA diagnosis or any time thereafter were included. Cox proportional hazard models were used to evaluate risk factors for aortic dissection/rupture.

RESULTS

The study included 33 patients (91% women) with GCA and aortic aneurysms. Mean age at diagnosis of aortic aneurysm was 83.6 years. There were 27 thoracic aneurysms and 19 abdominal aneurysms. Eight patients developed aortic dissection/rupture (both thoracic and abdominal aorta in 5 cases, thoracic aorta only in 2 cases, and isolated abdominal aorta in 1 case).Older age (hazard ratio [HR], 0.27 per 10 years; 95% confidence interval [CI], 0.09-0.86) and later calendar year at diagnosis of aortic aneurysm (HR, 0.29 per 10 years; 95% CI, 0.13-0.69) were associated with decreased risk of dissection/rupture. Size of the thoracic aneurysm (HR, 1.17; 95% CI, 0.69-1.99) was not associated with dissection/rupture. Histopathology showed active aortitis in 4 of 7 patients with aortic dissection/rupture compared with 0 of 7 patients with aortic aneurysm without dissection/rupture.

CONCLUSIONS

Aneurysm size was not a predictor of aortic dissection/rupture in this cohort of patients with GCA. The higher frequency of active aortitis in patients with dissection suggests that active inflammation may play a role.

Fever of unknown origin, giant cell arteritis, and aortic dissection

Giant cell arteritis is one of the most frequent causes of pyrexia of unknown origin after infectious or malignant causes have been ruled out. In this case report we describe a 66-year old female patient, who after five weeks of remitting fever developed a life-threatening, painless severe aortic dissection. The timely use of modern imaging technologies such as magnetic resonance angiography or positron emission computed tomography could in the future be of help to recognize aortic involvement early and to avoid this devastating complication in patients with fever of unknown origin.

Giant Cell Arteritis and Polymyalgia Rheumatica: 2016 Update

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are both more common among people of North European decent than among Mediterranean people. Women are 2-3 times more commonly affected. Giant cell arteritis and PMR are extremely rare before age 50 years. Polymyalgia rheumatica may be "isolated" or associated with GCA. There is increased expression of inflammatory cytokines in temporal arteries of PMR patients, without overt histological evidence of arteritis. One-third of "isolated" PMR patients have vascular uptake in positron emission tomography (PET) scans, suggesting clinically unrecognized, "hidden" GCA. Typical manifestations of GCA are headache, tenderness over temporal arteries, jaw claudication, PMR, acute vision loss, and low-grade fever. Bilateral aching of the shoulders with morning stiffness is typical for PMR. In both conditions sedimentation rate and C-reactive protein are elevated, and anemia and thrombocytosis may occur. Color duplex ultrasonography of the temporal arteries may aid in GCA diagnosis. Temporal artery biopsy showing vasculitis, often with giant cells, confirms GCA diagnosis. In cases with negative biopsy one must rely on the clinical presentation and laboratory abnormalities. The diagnosis of PMR is made primarily on clinical grounds. Other conditions that may mimic GCA or PMR must be excluded. Glucocorticoids are the treatment of choice for both conditions. Prompt treatment is crucial in GCA, to prevent irreversible complications of acute vision loss and stroke. Addition of low-dose aspirin may further prevent these complications. The average duration of treatment is 2-3 years, but some patients require a prolonged course of treatment, and some may develop disease-related or treatment-related complications. No steroid-sparing agent has been proven to be widely effective thus far, but some promising therapeutic agents are currently being studied.

The Expanding Role of Imaging in Systemic Vasculitis

Various imaging modalities, including color duplex ultrasonography, CT angiography, magnetic resonance angiography, and PET, are emerging as important aids to the diagnosis, staging, evaluation of disease activity and response to treatment in systemic vasculitis. Although large-vessel vasculitis is the main target of imaging, refinement and increasing accuracy of imaging modalities are also providing useful information in the evaluation of medium-vessel and small-vessel vasculitis.

Giant cell arteritis

Giant cell arteritis (GCA) is the most common vasculitis of the elderly. The diagnosis can be challenging at times because of the limitation of the American Rheumatology Association (ARA) classification criteria and the significant proportion of biopsy-negative patients with GCA. We discuss the role of advanced imaging techniques, including positron emission tomography (PET) scanning, in establishing diagnosis and improved histopathology techniques to improve the sensitivity of temporal artery biopsy. There have been significant advances in the understanding of the pathogenesis of GCA, particularly the role of cytokine pathways such as the interleukins, IL-6-IL-17 axis, and the IL-12-interferon-γ axis and their implication for new therapies. We highlight that glucocorticoids remain the primary treatment for GCA, but recognize the risk of steroid-induced side effects. A number of pharmacotherapies to enable glucocorticoid dose reduction and prevent relapse have been studied. Early diagnosis and fast-track pathways have improved outcomes by encouraging adherence to evidence-based practice.

Blocking interferon γ reduces expression of chemokines CXCL9, CXCL10 and CXCL11 and decreases macrophage infiltration in ex vivo cultured arteries from patients with giant cell arteritis

BACKGROUND

Interferon γ (IFNγ) is considered a seminal cytokine in the pathogenesis of giant cell arteritis (GCA), but its functional role has not been investigated. We explored changes in infiltrating cells and biomarkers elicited by blocking IFNγ with a neutralising monoclonal antibody, A6, in temporal arteries from patients with GCA.

METHODS

Temporal arteries from 34 patients with GCA (positive histology) and 21 controls were cultured on 3D matrix (Matrigel) and exposed to A6 or recombinant IFNγ. Changes in gene/protein expression were measured by qRT-PCR/western blot or immunoassay. Changes in infiltrating cells were assessed by immunohistochemistry/immunofluorescence. Chemotaxis/adhesion assays were performed with temporal artery-derived vascular smooth muscle cells (VSMCs) and peripheral blood mononuclear cells (PBMCs).

RESULTS

Blocking endogenous IFNγ with A6 abrogated STAT-1 phosphorylation in cultured GCA arteries. Furthermore, selective reduction in CXCL9, CXCL10 and CXCL11 chemokine expression was observed along with reduction in infiltrating CD68 macrophages. Adding IFNγ elicited consistent opposite effects. IFNγ induced CXCL9, CXCL10, CXCL11, CCL2 and intracellular adhesion molecule-1 expression by cultured VSMC, resulting in increased PBMC chemotaxis/adhesion. Spontaneous expression of chemokines was higher in VSMC isolated from GCA-involved arteries than in those obtained from controls. Incubation of IFNγ-treated control arteries with PBMC resulted in adhesion/infiltration by CD68 macrophages, which did not occur in untreated arteries.

CONCLUSIONS

Our ex vivo system suggests that IFNγ may play an important role in the recruitment of macrophages in GCA by inducing production of specific chemokines and adhesion molecules. Vascular wall components (ie, VSMC) are mediators of these functions and may facilitate progression of inflammatory infiltrates through the vessel wall.

Imaging in systemic vasculitis

PURPOSE OF REVIEW

Imaging is becoming a relevant tool for the assessment of patients with systemic vasculitis. This review focuses on recently generated data with potential clinical impact in the diagnosis, evaluation of disease extent and management of systemic vasculitis.

RECENT FINDINGS

Temporal artery examination by color duplex ultrasonography (CDUS) is a valuable approach to the diagnosis of giant-cell arteritis. Evaluation of additional arteries may increase its diagnostic performance. However, CDUS-specific findings may not be detected in arteries with early inflammation and CDUS-guidance of temporal artery biopsy does not seem to significantly increase its diagnostic yield. Large-vessel involvement detected by computed tomography angiography occurs in two out of three of patients with giant-cell arteritis at diagnosis. Furthermore, significant ascending aortic dilatation can be observed in one out of three of patients after long-term follow-up. Objective cut-offs for detecting large-vessel inflammation by positron emission tomography (PET) are trying to be established through prospective studies. PET may also contribute to the assessment of disease extent in patients with ANCA-associated vasculitis or Behçet's disease.

SUMMARY

Data generated by existing and emerging imaging techniques are expected to have a major impact in the diagnosis, appraisal of disease extent, evaluation of disease activity and response to treatment in patients with systemic vasculitis.

Advances in the diagnosis of large vessel vasculitis

The diagnosis of large-vessel vasculitis has experienced substantial improvement in recent years. While Takayasu arteritis diagnosis relies on imaging, the involvement of epicranial arteries by giant-cell arteritis facilitates histopathological confirmation. When appropriately performed temporal artery biopsy has high sensitivity and specificity. However, an optimal biopsy is not always achievable and, occasionally, the superficial temporal artery may not be involved. Imaging in its various modalities including colour-duplex ultrasonography, computed tomography angiography, magnetic resonance angiography and positron emission tomography, are emerging as important procedures for the diagnosis and assessment of disease extent in large-vessel vasculitis. Recent contributions to the better performance and interpretation of temporal artery biopsies as well as advances in imaging are the focus of the present review.

Giant cell arteritis: Current treatment and management

Glucocorticoids remain the cornerstone of medical therapy in giant cell arteritis (GCA) and should be started immediately to prevent severe consequences of the disease, such as blindness. However, glucocorticoid therapy leads to significant toxicity in over 80% of the patients. Various steroid-sparing agents have been tried, but robust scientific evidence of their efficacy and safety is still lacking. Tocilizumab, a monoclonal IL-6 receptor blocker, has shown promising results in a number of case series and is now being tested in a multi-centre randomized controlled trial. Other targeted treatments, such as the use of abatacept, are also now under investigation in GCA. The need for surgical treatment is rare and should ideally be performed in a quiescent phase of the disease. Not all patients follow the same course, but there are no valid biomarkers to assess therapy response. Monitoring of disease progress still relies on assessing clinical features and measuring inflammatory markers (C-reactive protein and erythrocyte sedimentation rate). Imaging techniques (e.g., ultrasound) are clearly important screening tools for aortic aneurysms and assessing patients with large-vessel involvement, but may also have an important role as biomarkers of disease activity over time or in response to therapy. Although GCA is the most common form of primary vasculitis, the optimal strategies for treatment and monitoring remain uncertain.

Clinical diagnosis and management of large vessel vasculitis: giant cell arteritis

Large vessel vasculitis (LVV) covers a spectrum of primary vasculitides predominantly affecting the aorta and its major branches. The two main subtypes are giant cell arteritis (GCA) and Takayasu arteritis (TA). Less commonly LVV occurs in various other diseases. Clinical manifestations result from vascular stenosis, occlusion, and dilation, sometimes complicated by aneurysm rupture or dissection. Occasionally LVV is discovered unexpectedly on pathological examination of a resected aortic aneurysm. Clinical evaluation is often unreliable in determining disease activity. Moreover, the diagnostic tools are imperfect. Acute phase reactants can be normal at presentation and available imaging modalities are more reliable in delineating vascular anatomy than in providing reliable information on degree of vascular inflammation. Glucocorticoids are the mainstay of therapy of LVV. Patients may develop predictable adverse effects from long-term glucocorticoid use. Several steroid-sparing agents have also shown some promise and are currently in use. Endovascular revascularization procedures and open surgical treatment for aneurysms and dissections are sometimes necessary, but results are not always favorable and relapses are common. This article, the first in a series of two, will be devoted to GCA and isolated (idiopathic) aortitis, while TA will be covered in detail in the next article.

Effect of glucocorticoid treatment on computed tomography angiography detected large-vessel inflammation in giant-cell arteritis. A prospective, longitudinal study

Computed tomography angiography (CTA) detects signs of large-vessel vasculitis (LVV) in about 67.5% of patients with giant-cell arteritis (GCA) at the time of diagnosis and early aortic dilatation in 15%. The outcome of CTA-findings of LVV upon glucocorticoid treatment has not been prospectively evaluated. The aim of our study was to prospectively assess glucocorticoid-induced changes in CTA findings of LVV in patients with GCA. Forty biopsy-proven GCA patients evaluated by CTA at diagnosis were prospectively followed and scheduled a new CTA approximately after 1 year of treatment. Vessel wall thickening, diameter, and contrast enhancement of the aorta and its tributaries were evaluated. Results were compared to those obtained at the time of diagnosis. CTA was repeated to 35 patients after a median follow-up of 13.5 months (IQ25-75% 12.4-15.8). Arterial wall thickening was still present in 17 patients (68% of the patients who initially had LVV). The number of affected segments and wall thickness at various aortic segments significantly decreased and no patients developed new lesions, new aortic dilation or increase in previous dilation. Contrast enhancement disappeared in 15 (93.75%) of 16 patients in whom this finding could be assessed. Signs of LVV improve with treatment. While contrast enhancement resolves in the majority of patients, vessel wall thickening persists in two thirds. However, the number of affected aortic segments as well as aortic wall thickness significantly decreases. Longer follow-up is necessary to determine the clinical significance of persisting wall thickening and its relationship with relapses or subsequent development of aortic dilatation or large-vessel stenoses.

Coronary artery disease in giant cell arteritis: a systematic review and meta-analysis

OBJECTIVE

To investigate the association between giant cell arteritis (GCA) and risk of coronary artery disease (CAD).

METHODS

We conducted a systematic review and meta-analysis of observational studies that reported relative risks, hazard ratios, or standardized incidence ratios with 95% confidence interval comparing CAD risk in patients with GCA versus non-GCA controls. Pooled risk ratios and 95% confidence intervals were calculated using a random-effect, generic inverse variance of DerSimonian and Laird.

RESULT

Six studies with 10,868 patients with GCA and 245,323 controls were identified and included in our data analysis. The pooled risk ratio of CAD in patients with GCA was 1.51 and did not achieve statistical significance (95% CI: 0.88-2.61). The statistical heterogeneity was high with an I(2) of 97%.

CONCLUSION

In contrast to other chronic systemic inflammatory disorders, our meta-analysis did not show any statistically significant increased risk of CAD among patients with GCA.