Synchronous and Metachronous Thoracic Aortic Aneurysms in Patients With Abdominal Aortic Aneurysms: A Systematic Review and Meta-Analysis.

Background The prevalence of thoracic aortic aneurysms (TAA) in patients with known abdominal aortic aneurysms (AAA) is not well known and understudied. Our aim was to conduct a systematic review and meta-analysis of the overall prevalence of synchronous and metachronous TAA (SM-TAA) in patients with a known AAA and to understand the characteristics of this sub-population. Methods and Results We searched MEDLINE, EMBASE, and CENTRAL (Cochrane Central Register of Controlled Trials) from inception to November 2019 for all population-based studies reporting on the prevalence of SM-TAAs in a cohort of patients with AAA. Article screening and data extraction were performed by 2 authors and data were pooled using a random-effects model of proportions using Freeman-Tukey double arcsine transformation. The main outcome was the prevalence of SM-TAAs in patients with AAAs. Secondary outcomes were the prevalence of synchronous TAAs, metachronous TAAs, prevalence of TAAs in patients with AAA according to the anatomic location (ascending, arch, and descending) and the differences in prevalence of these aneurysms according to sex and risk factors. Six studies were included. The pooled-prevalence of SM-TAA in AAA patients was 19.2% (95% CI, 12.3-27.3). Results revealed that 15.2% (95% CI, 7.1-25.6) of men and 30.7% (95% CI, 25.2-36.5) of women with AAA had an SM-TAA. Women with AAA had a 2-fold increased risk of having an SM-TAA than men (relative risk [RRs], 2.16; 95% CI, 1.32-3.55). Diabetes mellitus was associated with a 43% decreased risk of having SM-TAA (RRs, 0.57; 95% CI, 0.41-0.80). Conclusions Since a fifth of AAA patients will have an SM-TAA, routine screening of SM-TAA and their clinical impact should be more thoroughly studied in patients with known AAA.