Prevalence and risk factors for abdominal aortic aneurysms in older adults with and without isolated systolic hypertension

Abstract

An association between abdominal aortic aneurysm (AAA) and atherosclerotic disease has been recognized and may be due to shared risk factors. A consistent relation between blood pressure and AAA has not been found. AAA was compared between those with and without isolated systolic hypertension (ISH) and prevalence of aortic atherosclerosis was evaluated. Abdominal aortic ultrasound was performed in 266 people, 143 with ISH and 123 age-similar controls. AAA was defined as an infrarenal aortic diameter of > or = 3.0 cm or an infrarenal-to-suprarenal diameter ratio of > or = 1.2. The average age of participants was 73 years. Overall prevalence of AAA was 9.4%, 11.9% in those with ISH and 6.5% among normotensives (p = 0.134). Multivariate analysis revealed male gender (p <0.001), higher low-density lipoprotein (p <0.001), higher pulse pressure (p = 0.032), and current smoking (p = 0.012) to be independent predictors of AAA. When evaluating aortic atherosclerosis, those with AAA had significantly larger diameters of the iliac arteries along with greater intimamedia thickness of the iliac arteries. Those with and without aneurysms had a similar prevalence of plaque (89% to 96%), but measured plaques tended to be larger among those with than without AAA (p <0.001). Progression of AAA after 1 year was observed in 8 participants, with a mean diameter change of 3.42 mm. AAA was found to be independently associated with pulse pressure but not with systolic blood pressure. Patients with AAA also had greater wall thickness and greater diameter of the iliac arteries, which are probably associated with the underlying disease process.