Familial Clustering of Aortic Size, Aneurysms, and Dissections in the Community

Background: Ruptured aortic aneurysm and aortic dissections are potentially preventable disorders associated with high mortality. Screening of individuals at risk may translate into elective surgical interventions and lowered mortality. It is uncertain if the risk of aortic dilation of varying degrees aggregates within families. Methods: We investigated the risk of having thoracic and abdominal aortic sizes in the highest quartile (measured by computed tomography scans and indexed for body size) if at least 1 parent did so in the Framingham Heart Study cohorts, and estimated the incidence rates and hazard ratios of developing aortic aneurysm or dissection among first-degree relatives of those with aortic aneurysm or dissection, in comparison with age-and sex-matched controls (1:10 for aortic aneurysm and 1:100 for aortic dissection) using the Danish nationwide administrative registries. Results: In the Framingham Heart Study, offspring (n=235) whose parent(s) had a sex-and age-standardized aortic size in the upper quartile had a multivariable-adjusted ≈3-fold increased odds ratio of belonging to the upper quartile themselves. In Denmark, a total of 68 939 individuals (mean age, 42 years) had a first-degree relative with aortic aneurysm and 7209 persons (mean age, 39 years) had a first-degree relative with aortic dissection. During an average follow-up of 7 years, first-degree relatives of patients with aortic aneurysm and dissection had a hazard ratio of 6.70 (95% CI, 5.96-7.52) for developing aortic aneurysm and a hazard ratio of 9.24 (95% CI, 5.53-15.44) for dissection in comparison with matched controls. These estimates remained unchanged on adjusting for several comorbidities, including prevalent hypertension, bicuspid aortic valve, and the Marfan syndrome. For both aortic aneurysm and dissections, the absolute event rates approached 1 per 1000 person-years for first-degree relatives versus 11 to 13 (aortic aneurysm) and 2 to 3 (aortic dissections) per 100 000 person-years among controls. Conclusions: Increased aortic size, a precursor of aortic aneurysm and a risk factor for dissection, clusters in families. The incidence rates of aortic aneurysm and dissections approach the incidence rates of other common cardiovascular conditions in first-degree relatives, supporting the use of systematic screening for these conditions.