Whole aorta imaging shows increased risk for thoracic aortic aneurysms and dilatations in relatives of abdominal aortic aneurysm patients

Objective: For relatives of abdominal aortic aneurysm (AAA) patients, guidelines recommend abdominal imaging aimed at early detection and management of AAA, and do not include screening for thoracic aortic aneurysms (TAA). We aimed to investigate if TAA occur in undiagnosed relatives of patients with AAA without a known genetic susceptibility for aneurysms, similar to families with identified genetic susceptibilities for aneurysms like in Marfan and Loeys-Dietz syndrome, where both AAAs and TAAs occur. Methods: Relatives of patients with AAA were invited for noncontrast whole aorta computed tomography (CT) screening. Systematic measurements of the CT scans were used to detect aneurysms and dilatations. Classification into familial and nonfamilial was based on reported family histories. In addition, aneurysm gene panel testing of AAA index cases was used for the classification of high vs unknown genetic risk (high genetic risk: familial aneurysm or a pathogenic/likely pathogenic (P/LP) in an aneurysm gene; unknown genetic risk: no family history or P/LP). Results: Whole aorta imaging of 301 relatives of 115 index patients with AAA with noncontrast CT scans showed a 28-fold increase in TAAs in relatives (1.7% [P < .001] vs the age-adjusted population) and a high frequency of thoracic dilatations in 18% of the relatives. Thoracic aneurysms and dilatations in relatives occurred even when index patients were unaware of familial aneurysms. AAA was increased in the relatives compared with the age-adjusted population (8%; P < .001). Conclusions: An increased risk for thoracic aneurysms and dilatations was detected by whole aorta imaging of relatives of index patients with AAA, even when index patients were unaware of familial aneurysms. These results indicate still unknown shared genetic susceptibilities for thoracic and abdominal aneurysms. Therefore, imaging of the whole aorta of relatives of all abdominal aneurysm patients, will improve early detection of aortic aneurysms in relatives of all patients with AAA.