Large-Vessel Giant Cell Arteritis: Diagnosis, Monitoring and Management

Matthew J. Koster; Eric L. Matteson; Kenneth J. Warrington

Disclosures

Rheumatology. 2018;57(2):ii32-ii42. 

In This Article

Abstract and Introduction

Abstract

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.

Introduction

GCA is a chronic, idiopathic, granulomatous vasculitis of the medium and large arteries.[1] It comprises overlapping phenotypes, including classic cranial arteritis and extra-cranial GCA, otherwise known as large-vessel GCA (LV-GCA).[2] Initially considered a form of vasculitis primarily involving the carotid and vertebral artery branches,[3] autopsy studies have shown histological evidence of large-vessel involvement in 80% of cases[4,5] and imaging studies of patients with GCA have demonstrated that extensive radiographic large-vessel involvement (e.g. aorta and its major branches) is present in up to 83% of patients.[4–11] Increased awareness of large-artery involvement is paramount because patients with GCA are 17 times more likely to develop aneurysms of the thoracic aorta compared with their age/sex-matched comparators,[12] and occurrence of this complication is associated with a significant increase in mortality.[13] In addition, aortic aneurysm/dissection has been shown to occur in one in every five patients with GCA and large-artery stenosis in one in every eight.[14] The time from onset of large-artery symptoms to diagnosis may be prolonged,[14] and the presence of active arterial inflammation appears to play a role in predicting aortic dissection/rupture,[15] thus highlighting the importance of a timely diagnosis of LV-GCA to ensure prompt initiation of appropriate treatment.

Advances in non-invasive arterial imaging have led to greater understanding of the frequency of LV-GCA, but limited data are available to provide guidance on the modality best suited for either detection of large-vessel involvement or monitoring its response to treatment. While glucocorticoids have been the mainstay of GCA management for over six decades, their prolonged use is associated with adverse effects in up to 89% of patients.[16] Recent studies suggest that newly emerging biologic therapies, such as tocilizumab, can be effective and safe steroid-sparing options in patients with GCA.[17–20] However, data specifically evaluating the effectiveness of biologic therapies in the treatment of large-vessel involvement in GCA are limited. Herein, we describe current understanding and uncertainties related to LV-GCA, with particular focus on the diagnosis, monitoring and management of GCA.

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