An Update on Childhood-Onset Takayasu Arteritis

Takayasu Arteritis (TAK) is a rare large vessel vasculitis affecting the aorta and its major branches. The heterogeneous and often severe clinical manifestations result from systemic and local inflammation as well as end-organ ischemia. Disease flares are common and contribute to accrued damage over time with significant morbidity and mortality. Newer understanding of the pathogenesis in TAK has paved the way for the use of pathway targeting agents such as tumor necrosis factor (TNF)α- or interleuking (IL)-6-inhibitors with improved disease control. Nevertheless, long-term data are lacking, particularly in children; prognosis often remains guarded and the disease burden high. This article aims at providing a comprehensive review of childhood-onset TAK with a focus on recent publications.

Overview of imaging in adult- and childhood-onset Takayasu arteritis

Takayasu Arteritis is an idiopathic large vessel vasculitis, that affects young adults and children and can lead to ischemia and end-organ damage. Vascular imaging is crucial for diagnosis, assessment of disease extent and management of the disease. In this article, we critically review evidence for the clinical use of the different imaging modalities conventional angiography, magnetic resonance imaging, computed tomography, Doppler ultrasound and ¹⁸fluorodeoxyglucose positron emission tomography. We thereby focus on their clinical applicability, challenges and specific use in children.

Childhood-onset Takayasu Arteritis

Childhood-onset Takayasu Arteritis (cTAK) is a rare, large-vessel type of vasculitis seen in children, mainly affecting the aorta and its major branches. Clinical manifestations are often severe and arise as a result of systemic and local inflammation, along with end-organ ischemia. Disease flares are common and the disease burden is high, with a significant rate of morbidity and mortality. Recent advances in understanding the underlying disease pathobiology resulted in the use of pathway-targeting agents, such as TNF- or IL-6 inhibitors with improved disease control. Nonetheless, the prognosis often remains guarded and the accrued damage is significant. This review aims at summarizing the recent evidence and observations regarding this condition, with a focus on pediatric publications.

The Role of Vascular Imaging to Advance Clinical Care and Research in Large-Vessel Vasculitis

Purpose of the Review

The two main forms of large-vessel vasculitis (LVV) are giant cell arteritis (GCA) and Takayasu's arteritis (TAK). Vascular imaging can characterize disease activity and disease extent in LVV. This review critically analyzes the clinical utility of vascular imaging in LVV and highlights how imaging may be incorporated into the management and study of these conditions.

Recent Findings

There are multiple imaging modalities available to assess LVV including ultrasonography, CT angiography (CTA), magnetic resonance angiography (MRA), and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET). As these techniques are refined, imaging may be increasingly useful to evaluate the cranial arteries and the aorta and its primary branches. In addition, vascular imaging may be useful to monitor disease activity and may have prognostic value to predict future clinical events.

Summary

There are strengths and weaknesses associated with vascular imaging that should be considered when evaluating patients with LVV. Vascular imaging will likely play an increasingly important role in the clinical management of patients and the conduct of research in LVV and may ultimately be incorporated as outcome measures in clinical trials in these conditions.

Vessel wall plasticity in large vessel giant cell arteritis: an ultrasound follow-up study

Objectives

To assess changes of arterial vessel wall morphology in large vessel GCA patients (LV-GCA) by repeated US.

Methods

Patients with LV-GCA on US examination were followed up 6, 12 and 24 months after diagnosis by US of the temporal, vertebral, carotid (common, internal, external), subclavian, axillary, femoral (deep, superficial and common) and popliteal arteries. Clinical and laboratory data were assessed at each visit. Vessel wall thickening was classified as moderate, marked or arteriosclerotic.

Results

A total of 42 patients (26 female) with a median age of 75 years at diagnosis had in median 2 (range 1–3) US follow-up exams. Twenty-eight had both LV and temporal artery involvement and 14 had LV-GCA only. The common carotid, subclavian, axillary, popliteal and/or superficial femoral artery were most commonly involved. Reduction of LV wall thickening occurred in 45% of patients during follow-up, corresponding to 71 of the 284 (25%) initially ‘vasculitic’ LV segments. In contrast, a reduction of vessel wall thickening in the temporal artery was found in 85% of patients. Of the LVs, the vertebral, axillary, subclavian and deep femoral arteries were most likely to improve. There was no difference in relapses or the received cumulative steroid dose between patients with or without a reduction of vessel wall thickening (temporal artery or LV) during follow-up.

Conclusion

Regression of wall thickening within the LV is significantly less common than in the temporal artery and irrespective of clinical remission. Morphological regression does not seem to be a useful predictor for relapses.

Diagnostic accuracy of positron emission tomography for assessment of disease activity in large vessel vasculitis

AIM

To determine the diagnostic yield of ¹⁸ F-fluorodeoxyglucose positron emission tomography (PET) in disease activity assessment of large vessel vasculitides (LVV).

METHODS

Patients with LVV who had undergone PET (between 2004 and June 2010) or PET co-registered with computed tomography (PET/CT; since June 2010) were identified. Clinical disease activity was assessed using established scoring systems. PET images were reviewed by two blinded nuclear medicine physicians. Uptake of the aortic wall was compared to the liver uptake utilizing a visual 4-point score, with a vessel wall uptake similar or higher than liver uptake considered as active disease. Various target-to-background ratios were calculated. Receiver operator characteristics analysis was applied to determine the diagnostic accuracy of PET for detecting clinically active disease. Interobserver agreement of visual readings was measured with Cohen´s kappa.

RESULTS

Eighty examinations in 62 patients were analyzed, with a mean time between diagnosis and PET of 106 ± 171 weeks. Fifty-seven cases were finally classified as clinically active and 23 cases as clinically inactive. With a cut-off value of 1.3, the aorta-to-liver ratio yielded a sensitivity and specificity of 84.2% and 82.6% (area under the curve 0.9). Overall, sensitivity and specificity of visual analysis were 68.4% and 91.3%, but sensitivity decreased to 54% in patients treated for more than 3 months. Interobserver agreement of visual rating was excellent (κ: 0.93).

CONCLUSION

Positron emission tomography is specific and reliable in disease activity assessment of LVV, but lacks sensitivity for detecting active disease in patients under long-term immunosuppressive treatment.

Relapses in three patients with Takayasu arteritis under tocilizumab treatment detected by contrast enhanced ultrasound

Abstract. Takayasu arteritis (TA) is a rare large vessel vasculitis, affecting the aorta and its major branches, typically in young women. In this case report, we present three cases of young women of Caucasian descent who experienced relapses while under treatment with the monoclonal humanized antibody to the interleukin 6 receptor, tocilizumab. Active vasculitic lesions of the supraaortic (common carotid and axillary) arteries were detected and characterized via high resolution contrast enhanced ultrasound. Based on these cases, we discuss the potential role of contrast enhanced ultrasound in the diagnosis and follow-up of TA as well as the current data on the efficacy of tocilizumab in the treatment of TA.