Abstract 1906: Abdominal Aortic Aneurysms in the Cardiovascular Health Study: 12 Year Follow-Up
In the Cardiovascular Health Study (CHS), small abdominal aortic aneurysms (AAA) were found to be independently predictive of cardiovascular mortality after 4.5 years. We now report long term 12 year follow up after initial screening. In 1992–93, 4734 of the 5,888 participants in the CHS ages ≥ 65 had an abdominal aortic ultrasound evaluation. An AAA was defined as an infrarenal aortic diameter ≥3.0 cm or an infrarenal to suprarenal ratio of ≥1.2. Of the 4734 participants screened, 416 met our AAA definition. During the 12 year follow-up period, 55 out of the 4734 participants had an AAA repair (at baseline 37/55 met our AAA definition and 49/55 had infrarenal aortic diameter ≥ 2.5 cm) and 1822 participants died (10 of AAA). Of the 416 with AAA, 231 died (8 of AAA, 107 of other cardiovascular disease (CVD) causes and 116 of non-cardiovascular causes). Using Cox proportional hazard models and adjusting for age, race, measures of subclinical disease, and CVD risk factors, the presence of an AAA was associated with a higher risk of incident CVD events and total mortality for men (hazard ratio (HR) =1.51 and 1.64, respectively) and women (HR= 1.34 and 1.60, respectively<0.05 for all) as compared with those without an AAA. When an AAA was defined as an infra-renal aortic diameter ≥ 3.0 cm only, the risk for incident CVD events and total mortality increased for men (HR=1.91 and 1.66) and women (2.27 and 2.46, respectively, p<0.05 for all). Furthermore, infrarenal aortic diameters (2.0-<3.0 cm) were associated with a 32% higher risk of incident CVD events (women only, p<0.05) and a 26% and 29% higher risk of total mortality for men and women, respectively (p<0.05 for all) as compared with those with diameters of <2.0 cm. While people with AAA are at risk for AAA repair and AAA related death, in the CHS cohort after a one time ultrasound screening of the abdominal aorta, we observed that few participants actually had AAA repairs or died from an AAA. Among those who had a repair or died of AAA, the majority had an AAA at baseline. Those with an AAA or even small increased infra-renal aortic diameters, however, had significantly higher risks of future CVD events and total mortality. The higher CVD risk suggests that the primary approach to small AAA should be aggressive CVD risk factor management.