From the Guidelines
The Ankle-Brachial Index (ABI) can reflect iliac artery disease, but it may be normal at rest in cases of isolated iliac occlusive disease. The ABI is a useful screening tool that can detect significant stenosis or occlusion in the iliac arteries, which are major vessels supplying the lower extremities. An ABI value below 0.9 suggests peripheral artery disease, which may include iliac artery involvement 1. However, it's essential to understand that the ABI is a general indicator of lower extremity arterial disease and doesn't specifically localize the obstruction to the iliac segment.
In patients with suspected iliac artery disease, an abnormal ABI would typically prompt further diagnostic evaluation with imaging studies such as duplex ultrasound, CT angiography, or magnetic resonance angiography to confirm the diagnosis and precisely locate the stenosis 1. The ABI measurement involves comparing systolic blood pressures at the ankle to those at the arm, providing a ratio that reflects overall blood flow to the lower extremity. While the ABI is valuable for screening and monitoring treatment effectiveness, its main limitation in iliac disease is that it cannot distinguish between different anatomical locations of arterial obstruction in the lower extremity arterial tree.
Some key points to consider when interpreting ABI results include:
- The mode of determination of the ankle pressure can affect the ability of the ABI to diagnose PAD, with choosing the lower compared to the higher ankle pressure as the ABI numerator associated with better sensitivity 1
- The use of the higher pressure at the ankle is preferred to minimize overdiagnosis in healthy subjects and thus to avoid further unnecessary tests and treatment 1
- ABI results should be interpreted in the context of clinical symptoms and other diagnostic findings, as a normal ABI does not rule out iliac artery disease, particularly if it is isolated 1.
From the Research
Ankle-Brachial Index (ABI) and Iliac Artery Disease
- The Ankle-Brachial Index (ABI) is a widely used diagnostic tool for peripheral artery disease (PAD) [(2,3,4,5)].
- ABI measures the ratio of blood pressure in the ankles to that in the arms, and a low ABI value can indicate PAD [(2,3,4,5)].
- However, the question of whether ABI reflects iliac artery disease specifically is not directly addressed in the provided studies [(2,3,4,5,6)].
Relationship Between ABI and Iliac Artery Disease
- While ABI is a useful diagnostic tool for PAD, it may not specifically reflect iliac artery disease [(2,3,4,5)].
- Iliac artery disease refers to the narrowing or blockage of the iliac arteries, which supply blood to the legs [(2,3,4,5)].
- The provided studies focus on the diagnostic accuracy of ABI in detecting PAD, but do not provide direct evidence on its relationship with iliac artery disease [(2,3,4,5,6)].
Limitations of ABI in Detecting Iliac Artery Disease
- ABI may not be sensitive enough to detect iliac artery disease, as it measures blood pressure in the ankles and arms, but not specifically in the iliac arteries [(2,3,4,5)].
- Further studies are needed to investigate the relationship between ABI and iliac artery disease, and to determine the diagnostic accuracy of ABI in detecting iliac artery disease [(2,3,4,5,6)].