Abdominal aortic calcification or AAC is the deposition of calcium within the intimal or medial layers of the aortic wall. The presence of AAC is evidence of aortovascular disease and has been shown to be a marker of generalised atherosclerosis at other vascular beds e.g. coronary and carotid arteries, and/or medial calcifications seen in certain clinical populations and advanced ages.


Unlike coronary artery calcifications (CAC), AAC appears to be driven to a lesser extent by traditional atherosclerotic cardiovascular risk factors such as lipids. Instead, low muscle and bone mass and chronic kidney disease appear to be important drivers of higher prevalence and extent of AAC.
AAC can be assessed by expert readers on lateral thoracolumbar x-rays or vertebral fracture assessment images from bone density machines. The extent of calcification is semi-quantified based on the proportion of the calcification on the posterior and anterior aortic wall, relative to the adjacent lumbar vertebrae (L1 to L4). More recently new, state-of-the-art machine learning algorithms have been developed to automate this process.
Is AAC normal, and how does it affect the function of the aorta? A healthy aorta (no calcification) would not be visible on these images. Autopsy and imaging studies have identified that the iliac artery bifurcation and abdominal aorta are often the first sites where vascular calcification is seen.
While AAC is common in older people, it is not normal. AAC has been shown to increase aortic stiffness, raise central blood pressure and widen pulse pressure contributing to damage to high-flow, low-resistance organs such as the heart, brain and kidneys.
AAC and CVD
There is now good evidence that AAC is consistently related to higher cardiovascular disease (CVD) risk and poorer long-term prognosis in the general population and in people with chronic kidney disease.
AAC is also associated with increased risk of CVD events in middle-aged men and women without CAC. Importantly, AAC also predicts coronary heart disease events in addition to and independent of CAC and is more strongly related to CVD and all-cause deaths.
Taken together this emerging research suggests assessing AAC represents an early opportunity to identify people at risk of CVD events, often before the onset of CAC and provides additional prognostic information to CAC.
With regards to other health outcomes, AAC is related to poorer handgrip strength, the decline in handgrip strength over five years and increased long-term falls risk. Additionally higher AAC has been associated with low bone mineral density and increased risk of osteoporotic fractures.
AAC is inversely related to poorer cognitive function and more recently moderate to extensive AAC has been associated with a doubling in the risk of developing late-life dementia in older women. The exact mechanism(s) underlying these relationships remain unclear but are a developing area of research interest.
What can you do if AAC is seen on images? Currently, there are no guidelines or recommendations for when AAC is observed. If moderate to extensive AAC is seen in patients without known CVD, then consideration of traditional risk factors e.g. lipids, blood pressure and glycaemic control, as well as non-traditional risk factors such as renal function, muscle and bone mass may be warranted.
So, what to tell patients if AAC is seen on these images? Providing feedback of vascular imaging results to individuals, particularly those with moderate to extensive AAC, may be an opportunity to reinforce healthy lifestyle recommendations that improve CVD risk factor control. Exercise and dietary factors (e.g. fruit and vegetables rich in vitamin K1 and flavonoids) may help to reduce the progression of AAC and development of clinical CVD.
Multidisciplinary approaches incorporating dietitians and accredited exercise physiologists may be encouraged to help support patients with making these lifestyle changes.
Key messages
- Abdominal aortic calcification can be assessed on thoracolumbar x-ray or bone density assessment
- AAC is related to higher rates of cardiovascular disease
- Its finding can assist with reinforcing lifestyle advice to patients.
ED: A/Prof Lewis is a Heart Foundation Future Leader Fellow and board member of the WA Cardiovascular Research Alliance. Dr Smith is an accredited exercise physiologist and postdoctoral research fellow at ECU.
Both authors are members of the Nutrition & Health Innovation Research Institute at ECU.
Author competing interests – ECU has lodged a patent for automated assessment of abdominal aortic calcification. A/Prof Lewis is one of the named inventors on this patent.