What Does an ABI of 1.17 Mean?
An ABI of 1.17 is normal and indicates no evidence of peripheral artery disease (PAD), though it falls in the upper-normal range where you should remain alert for potential arterial stiffness, particularly in older adults or those with diabetes.
Interpretation Framework
Your patient's ABI of 1.17 falls within the normal range (0.90-1.40) according to the American Heart Association guidelines 1. This value:
- Rules out significant PAD - Values <0.90 are required to diagnose PAD 1
- Is not elevated enough to suggest arterial stiffness - Values >1.40 indicate non-compressible vessels and warrant further testing with toe-brachial index 1
- Does not indicate increased cardiovascular risk - Only ABIs <0.90 or >1.40 are associated with increased cardiovascular events and mortality 1
Clinical Context Matters
While 1.17 is technically normal, the AHA guidelines emphasize that values between 0.91 and 1.00 are considered "borderline" for cardiovascular risk 1. Your patient's value of 1.17 is comfortably above this borderline zone, suggesting even lower concern.
However, recent research suggests that high-normal ABI values (upper quartiles within the normal range) may be associated with left ventricular hypertrophy, particularly in hypertensive patients 2. This association likely reflects increased arterial stiffness and wave reflection rather than PAD.
What You Should Do
No further vascular testing is needed based on the ABI alone, unless:
- The patient has symptoms suggestive of PAD (claudication, rest pain, non-healing wounds) despite the normal ABI - then perform post-exercise ABI or imaging 1
- The patient has diabetes or chronic kidney disease - these conditions can cause medial arterial calcification leading to falsely elevated ABIs, and you should consider toe-brachial index if clinical suspicion remains 1
- The patient is elderly with significant cardiovascular risk factors - monitor for progression, as ABI can change over time
Key Pitfalls to Avoid
- Don't assume all normal ABIs are equivalent - Values in the 0.91-1.00 range warrant closer cardiovascular risk assessment than values like 1.17 1
- Don't ignore symptoms - If your patient has classic claudication symptoms, the normal ABI doesn't rule out PAD; proceed with post-exercise ABI testing 1
- Don't forget bilateral assessment - Always measure both legs, as PAD may be unilateral or asymmetric 1
Cardiovascular Risk Assessment
Unlike low or very high ABIs, an ABI of 1.17 does not independently increase cardiovascular risk and should not change your approach to cardiovascular risk reduction beyond standard risk factor management 1. The ABI provides incremental cardiovascular risk information primarily when abnormal (<0.90 or >1.40) 1.