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Risk Factors for Aortic Dilation in Individuals Aged 60-74 Years
Quick Takes
- Aortic dilation at one site confers increased risk for dilation at other sites. Ascending aortic and arch dilation are strongly associated (odds ratio, 8.4), as are abdominal aortic and iliac artery dilation (odds ratio, 9.9).
- Cardiovascular comorbidities associated with increased risk of aortic dilation include hypertension and atrial fibrillation, while diabetes is negatively associated with thoracic aortic dilation.
Study Questions:
What are the predominant risk factors for dilation of different portions of the aorta?
Methods:
Data were obtained from two population-based Danish screening studies, which included patients aged 60-74 years. Patients were randomized to undergo cardiovascular screening or participate as control subjects. Both women and men were recruited initially, but after a pilot study concluded that women were less likely to benefit from cardiovascular screening, only men were recruited. Noncontrast computed tomography (CT) scans were performed for aortic measurements. Aortic dilation was defined as observed diameter ≥25% greater than expected for sex, age, and body size; aneurysm was defined as observed diameter ≥50% greater than expected.
Results:
The study population included 14,989 subjects (14,235 men and 754 women, mean age was 68 ± 4 years). The prevalence of aortic dilation was significantly higher among men than women in all segments, aside from the arch. Ascending aortic dilation was present in 4.0% of men and 2.1% of women, and ascending aortic aneurysm was present in 0.1% for both sexes. Abdominal aortic dilation was present in 9.4% of men and 3.9% of women, with abdominal aortic aneurysm in 3.7% of men and 0.4% of women.
In multivariable logistic regression analysis, coexisting aortic dilation was a predictor of dilation in other segments. In particular, ascending aortic dilation was strongly associated with arch dilation (odds ratio [OR], 8.4; 95% confidence interval [CI], 5.6-12.6), and arch dilation was strongly associated with descending thoracic aortic dilation (OR, 6.1; 95% CI, 3.7-9.9). Abdominal aortic dilation was associated with descending thoracic aortic dilation (OR, 3.7; 95% CI, 2.8-4.8) and iliac artery dilation (OR, 9.9; 95% CI, 7.6-12.9) and more modestly associated with ascending aortic dilation (OR, 1.8; 95% CI, 1.4-2.3). Smoking was significantly associated with increased risk of abdominal aortic dilation (OR for current smoking, 4.2; 95% CI, 3.5-5.1) but not with ascending aortic dilation (OR, 0.7; 95% CI, 0.6-1.0). Hypertension was associated with increased risk of dilation in all segments (ORs ranging from 1.2-1.7). Atrial fibrillation was associated with increased risk of ascending and descending aortic dilation (ORs 1.9 and 1.5, respectively). Diabetes was associated with decreased risk of dilation in all thoracic aortic segments (ORs ranging from 0.4-0.6). The presence of aortic aneurysm in a first-degree relative was significantly associated with increased risk of ascending aortic and abdominal aortic dilation (ORs 1.6 and 1.9, respectively).
Conclusions:
Aortic dilation at one site confers increased risk for dilation at other sites. Cardiovascular comorbidities associated with increased risk of aortic dilation include hypertension and atrial fibrillation. Diabetes is associated with lower risk of thoracic aortic dilation.
Perspective:
The findings of this study support the practice of evaluating the entire aorta with axial imaging (CTA or magnetic resonance angiography) when an aortic aneurysm is initially diagnosed. A limitation of this study is its demographic scope. The Danish population is largely Caucasian, so generalizability of the findings to ethnically diverse populations may be limited. While women are generally at lower risk of abdominal aortic aneurysm than men, as reflected in US Preventive Service Task Force screening recommendations, women with multiple risk factors such as smoking, hypertension, and family history should be considered for screening, as recommended by the Society for Vascular Surgery. The negative association between diabetes and thoracic aortic dilation has been described previously, but mechanistic associations remain unclear and are deserving of further study.
Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Geriatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Atrial Fibrillation/Supraventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Interventions and Imaging, Interventions and Vascular Medicine, Computed Tomography, Nuclear Imaging, Hypertension, Smoking
Keywords: Aorta, Abdominal, Aortic Aneurysm, Aortic Aneurysm, Abdominal, Atrial Fibrillation, Cardiac Surgical Procedures, Diagnostic Imaging, Diabetes Mellitus, Dilatation, Geriatrics, Hypertension, Risk Factors, Secondary Prevention, Smoking, Tomography, Tomography, X-Ray Computed, Vascular Diseases
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