Increased risk for thoracic and abdominal aortic aneurysm in the relatives of abdominal aorta aneurysm patients

Abstract Introduction Genetic susceptibilities in aneurysm genes are risk factors for developing aneurysms of the aorta. This translates to a high aneurysm prevalence in relatives of aortic aneurysm patients. For relatives of abdominal aorta aneurysm (AAA) patients, guidelines recommend abdominal ultrasound screening for early detection and management, while for relatives of thoracic aorta aneurysm patients (TAA), transthoracic ultrasound of the ascending aorta and aortic root is recommended. Neither of these guidelines are designed to detect aneurysms in the whole aorta. The incidence of TAA in relatives of AAA index-patients is unknown and may determine whether abdominal ultrasound screening is sufficient for relatives of AAA patients or whether whole aorta screening should be recommended. Furthermore, focused screening of high risk relatives of aneurysm patients may improve the yield of aneurysm detection now that population frequencies are declining. Methods Whole aorta non-contrast CTs of relatives of AAA index-patients were collected retrospectively in a tertiary referral (2016 to 2021). Family history and DNA testing of AAA index-patients were used to classify relatives into high genetic risk (familial disease and/or pathogenic/likely pathogenic variant (P/LP) in an aneurysm gene) or unknown genetic risk (no familial disease or no P/LP detected). TAA were defined as ascending diameters ≥ 45mm or descending diameters ≥ 40mm. Thoracic aortic dilatations (TAD) were defined as ascending diameters of 40-45 mm or descending diameters of 35-40 mm. Abdominal diameters ≥30mm were classified as AAA and diameters between 25-29 mm as abdominal dilatations (AAD). References 1-3. Results CT scans (n=301 relatives, 47% male, age 58(50-65)) showed 34% aortic aneurysms and/or dilatations versus 14% in the general population (age adjusted, p<0.001). TAA was 28-times more frequent (2%, p<0001) and AAA 3 times more frequent (8%, p<0.001) than in the general population. Thoracic and abdominal dilatations occurred in 18% and 17% of relatives. Overall, males were 4 times more likely to have an aneurysm than females (p<0.05). Aneurysms and dilatations occurred at the same rate in relatives with or without a family history or a P/LP in an aneurysm gene. These results endorse total aorta screening for relatives of all AAA patients rather than restricting screening to the abdominal aorta. Conclusions Relatives of AAA patients had a high risk for thoracic and abdominal aneurysms as well as dilatations. This indicates that imaging of the whole aorta will improve early detection of aortic aneurysms in relatives both with and without a family history of aneurysms.