EXTENDED REPORT Should I send my patient with previous giant cell arteritis for imaging of the thoracic aorta? A systematic literature review and meta-analysis Sarah Louise Mackie, 1 Elizabeth M A Hensor, 1 Ann W Morgan, 1 Colin T Pease 2 Handling editor Tore K Kvien ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ annrheumdis-2012-202145). 1 NIHR-Leeds Musculoskeletal Biomedical Research Unit, Leeds Institute of Molecular Medicine, Leeds, West Yorkshire, UK 2 Department of Rheumatology, Leeds Teaching Hospitals NHS Trust, Leeds, West Yorkshire, UK Correspondence to Dr Sarah Louise Mackie, NIHR-Leeds Musculoskeletal Biomedical Research Unit, Leeds Institute of Molecular Medicine, Wellcome Trust Brenner Building, St James’s University Hospital, Leeds LS9 7TF, UK; s.l.mackie@leeds.ac.uk Received 7 June 2012 Revised 12 November 2012 Accepted 2 December 2012 Published Online First 22 December 2012 To cite: Mackie SL, Hensor EMA, Morgan AW, et al. Ann Rheum Dis 2014;73:143–148. ABSTRACT Objectives To review the literature in order to estimate how many previously unknown thoracic aortic aneurysms (TAAs) and thoracic aortic dilatations (TADs) might be detected by systematic, cross-sectional aortic imaging of patients with giant cell arteritis (GCA). Methods A systematic literature review was performed using Ovid Medline, Embase and the Cochrane Library. Studies potentially relevant to TAA/TAD were evaluated by two authors independently for relevance, bias and heterogeneity. Meta-analysis was performed using a random-effects model to estimate pooled prevalence. Results Two analyses of routinely collected administrative data suggested a threefold risk of TAA/dissection in GCA compared with controls. In GCA cohorts without systematic imaging, 2–8% had TAA. In the two best-reported studies, aneurysm dissection/rupture occurred in 1% and 6% of GCA cases. Aortic imaging studies had a variety of TAA/ TAD definitions, imaging methods and time points. There were limited data on age-matched controls. Three studies suggested that male sex may be a risk factor for TAA/TAD in GCA. On average, five to ten patients with GCA would need aortic imaging to detect one previously unknown TAA/TAD. Conclusions The data support an association between GCA and TAA/TAD compared with age-matched controls, but the true relative risk, and the time course of that risk, remains unclear. It is also unclear whether chest radiography is a sufficiently sensitive screening tool. Clinicians should retain a high index of suspicion for aortic pathology in patients with GCA. Before ordering imaging, clinicians should consider whether, and how, detecting aortic pathology would affect a patient’s management. INTRODUCTION Giant cell arteritis (GCA) is an age-related, large- vessel vasculitis with a well-described association with aortitis. In an autopsy study, half the cases with aortitis also had some evidence of polymyalgia rheumatica (PMR)/GCA, 1 while, in a surgical series, one-third of cases with active, non-infectious aortitis were attributed to GCA. 2 CT studies reveal aortic thickening (presumed aortitis) in 45–65% of patients with GCA at diagnosis, 3 4 and an ultra- sound study revealed abnormality of the abdominal aorta in 90% of patients with GCA at diagnosis. 5 The ascending aorta shows impaired elastic proper- ties even at presentation of GCA. 6 In the population, normal aortic diameter increases by 1 mm/decade. 78 The incidence of thor- acic aortic aneurysm (TAA), dissection and rupture together has been estimated for the Swedish popula- tion at 0.16 per 1000 person-years in men, and 0.09 per 1000 person-years in women, with a median age at diagnosis of 71 years and 40% overall still unruptured at diagnosis. 9 Abdominal aortic aneur- ysm (AAA) is observed in about 5% of men over 65 in ultrasound screening programmes. 10 Patients with GCA appear to have an elevated incidence of aortic aneurysm, particularly TAA, compared with the general population; the aneur- ysm may only be discovered some years after GCA diagnosis, in the event of (often fatal) dissection or rupture. 11 12 This late aneurysm development in GCA might be a consequence of cumulative inflam- matory damage to the smooth muscle and/or elastic laminae of the aortic wall, although it has also been proposed that the aortic inflammation in GCA is secondary to atrophy of the aortic smooth muscle. 13 There is pathological evidence of active giant cell aortitis in many reported cases of aortic dissection/rupture; also, patients with increased aortic fluorodeoxyglucose (FDG) uptake on posi- tron emission tomography (PET) at GCA diagnosis are more likely to develop aortic dilatation later. 14 Over time, aortic aneurysms in general enlarge by 1–10 mm/year 15–17 ; there are few data on whether this may occur more rapidly in TAAs that are caused by aortitis. It is important that the blood pressure of patients with TAA is aggressively con- trolled to avoid excessive aortic strain. Patients with unrepaired TAAs in general have a 1-, 3- and 5-year survival of approximately 65%, 36% and 20%, 15 18 although this depends on many factors including aneurysm size. 17 There are few data on mortality attributable to TAA that is caused by aor- titis. If a TAA ruptures, 76% of patients die within 24 h, whether or not they reach the operating table. 15 In atherosclerotic TAA, surgery is usually considered at >55 mm for ascending aortic TAA and >60 mm for descending aortic TAA, or in TAAs that grow at >10 mm/year. 15 For all these reasons, it is relevant to ask whether, how and when we should screen our patients with GCA for TAA. Here we focus on TAA rather than AAA because the imaging necessary for TAA diagnosis is potentially more burdensome for both patients and the health service, compared with the relative ease of diagnosing AAA. Current UK guidelines for management of GCA suggest a chest radiograph every 2 years to screen for TAA, 19 but chest radiography is not a very sen- sitive test for detecting TAA, with a sensitivity of Mackie SL, et al. Ann Rheum Dis 2014;73:143–148. doi:10.1136/annrheumdis-2012-202145 143 Clinical and epidemiological research group.bmj.com on January 27, 2016 - Published by http://ard.bmj.com/ Downloaded from