A Population-Based Study of the Incidence and Natural History of Degenerative Thoracic Aortic Aneurysms

Objective: To investigate the incidence and natural history of degenerative thoracic aortic aneurysms (TAAs) and compare results between ascending (aTAAs) and descending TAAs (dTAAs).

Patients and methods: This population-based cohort study used the Rochester Epidemiology Project database from January 1, 1995, through December 31, 2015. Patients were classified as the aTAA or dTAA group.

Results: Of 238 Olmsted County residents studied, 131 (55.0%) were women; 154 (64.7%) were in the aTAA group, and 84 (35.3%) were in the dTAA group. Median age was 77.0 years (interquartile range, 69.1-83.8 years). The overall age- and sex-adjusted incidence rate was 13.8 per 100,000 person-years (95% CI, 12.1 to 15.6) and varied from 9.9 in 1995 to 1999 to 19.0 in 2005 to 2009. It was 9.0 (95% CI, 7.5 to 10.4) for the aTAA and 4.9 (95% CI, 3.8 to 5.9) for the dTAA group. Overall 5-year survival was 62.5%, lower than the expected survival of 73.7% for the US 2010 census population (P<.001). The 5-year survival was 42.9% for the aTAA and 73.4% for the dTAA group (P<.001). On multivariable analysis, advanced age and smoking status were associated with all-cause mortality. The 5-year estimate of freedom from an aortic-related event was 80.0%, lower for dTAAs (67.8%) than for aTAAs (85.2%; P<.001). Maximal aortic diameter and dTAAs were associated with aortic-related events.

Conclusion: The incidence of TAAs was stable from 1995 to 2015 and mortality for those with TAAs remains higher than for the general population. Older age and smoking status were associated with overall mortality, whereas larger aneurysms and dTAAs were associated with aortic-related events.