Should I send my patient with previous giant cell arteritis for imaging of the thoracic aorta? A systematic literature review and meta-analysis.

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.