What Is the Ankle-Brachial Index (ABI) and Why It Matters for Heart Health

Cardiovascular disease is the leading cause of death worldwide—and most heart attacks and strokes occur in people who never saw it coming. One of the simplest and most powerful tools for assessing vascular health is the Ankle-Brachial Index (ABI), a non-invasive test that measures blood flow to your legs compared to your arms.

If you’ve never heard of ABI, you’re not alone. Yet this quick, low-cost screening test can reveal peripheral artery disease (PAD), an early warning sign of systemic atherosclerosis that significantly raises your risk for coronary artery disease, heart attack, stroke, and death.

In this article, you’ll learn:

• What the ABI is and how it works

• What your ABI number means

• What symptoms might warrant testing

• How the ABI compares to other vascular tests

• When to repeat it and what to do if your score is abnormal

• How to optimize vascular health using lifestyle, supplements, and advanced therapies

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What Is the Ankle-Brachial Index?

The Ankle-Brachial Index is a ratio derived by comparing the systolic blood pressure at your ankle to that at your arm (brachial artery). In healthy individuals, blood pressure should be equal or slightly higher at the ankle due to gravitational effects.

The Formula:

ABI = (Ankle Systolic Pressure) / (Brachial Systolic Pressure)

This number helps identify whether there is significant narrowing or blockage in the arteries supplying your legs.

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Why Is the ABI Important?

Early Detection of PAD

The ABI is most commonly used to screen for peripheral artery disease (PAD), a condition where arteries in the legs become narrowed due to plaque buildup. PAD is common but underdiagnosed and affects:

• ~20% of adults over age 60

• Smokers and diabetics at any age

• People with high cholesterol, high blood pressure, or a family history of vascular disease

Strong Predictor of Cardiovascular Events

PAD is not just a “leg problem”—it’s a marker of systemic atherosclerosis. Studies show that:

• Patients with low ABI scores have a 4–6x higher risk of heart attack or stroke

• ABI abnormalities may predict cardiovascular mortality independently of cholesterol levels

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How Is the ABI Test Performed?

The ABI is a simple, non-invasive procedure that takes about 10–15 minutes.

Here's how it works:

1. You lie flat on an exam table.

2. Blood pressure cuffs are placed on both arms and both ankles.

3. A Doppler ultrasound probe is used to detect arterial flow in the:

   • Brachial artery (arm)

   • Posterior tibial artery or dorsalis pedis artery (ankle)

4. Systolic pressures are recorded in each location.

5. The highest ankle pressure is divided by the highest brachial pressure to calculate ABI.

Example:

• Right ankle pressure = 130 mmHg

• Right arm pressure = 120 mmHg

• ABI = 130 / 120 = 1.08 (Normal)

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How to Interpret ABI Results

ABI Score	Interpretation	Meaning
1.00 – 1.29	Normal	No significant arterial narrowing
0.91 – 0.99	Borderline	May reflect early PAD or borderline circulation
0.41 – 0.90	Mild to moderate PAD	Some obstruction in leg arteries; consider imaging
0.00 – 0.40	Severe PAD	High risk of ischemia, ulcers, possible limb threat
>1.30	Non-compressible arteries	Often due to calcification (common in diabetes, CKD)

High ABI (>1.30):

May indicate vessel calcification rather than healthy circulation. Additional imaging may be required (e.g. toe-brachial index or arterial duplex ultrasound).

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Who Should Get an ABI Test?

You should consider ABI testing if you have:

• Leg pain while walking (claudication) that improves with rest

• Numbness, tingling, or coldness in your feet

• Non-healing wounds or ulcers on your legs or toes

• Weak or absent pulses in the legs

• Known atherosclerosis or carotid artery disease

• High cardiovascular risk (diabetes, smoking, high cholesterol)

ABI screening is especially important for:

• Adults >65 years

• Adults >50 years with diabetes or smoking history

• Anyone with vascular symptoms

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How Often Should ABI Be Repeated?

There are no strict guidelines for everyone, but general recommendations include:

• Every 2–3 years in high-risk patients

• Annually if there’s known PAD or symptoms are worsening

• After intervention (e.g. stenting or bypass) to monitor results

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ABI vs. Other Vascular Tests

Test	What It Measures	Use Case
ABI	Blood pressure ratio (ankle/arm)	PAD screening, CV risk stratification
Toe-Brachial Index	Pressure in toes vs. arms	For non-compressible arteries in diabetics
Arterial Duplex	Blood flow + vessel imaging	For precise location/severity of blockage
Pulse Volume Recording	Waveform analysis of blood flow	Assessing limb perfusion without Doppler
CT Angiography	Detailed imaging of arteries	Surgical planning or advanced disease mapping

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What to Do if Your ABI Is Abnormal

If ABI is <0.90 (PAD diagnosed):

• Begin aggressive cardiovascular risk reduction:

  • Stop smoking

  • Lower blood pressure

  • Control blood sugar

  • Optimize lipids (especially ApoB, sdLDL, and Lp(a))

• Consider:

  • Supervised exercise therapy

  • Vascular consult for imaging or intervention

  • Nutritional and lifestyle support

  • Peptide therapy (e.g., MOTS-c, BPC-157) for tissue healing and mitochondrial function

If ABI is >1.30:

• Evaluate for arterial stiffness or calcification

• Consider toe-brachial index or pulse wave velocity testing

• Optimize magnesium, vitamin K2, and bone-mineral balance

• Test for chronic kidney disease and insulin resistance

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How to Improve ABI Naturally

Even if you already have PAD, you can take steps to improve circulation and reduce disease progression.

1. Exercise (Supervised if Needed)

• 30–45 minutes daily of walking to near-discomfort improves leg perfusion

• Resistance training builds nitric oxide and lowers inflammation

• Consider tracking arterial stiffness with CAPWA or SphygmoCor if available

2. Anti-inflammatory Diet

• Prioritize omega-3s, leafy greens, and low-glycemic foods

• Avoid seed oils, refined sugars, and ultra-processed foods

• Aim for adequate protein: at least 1g/kg body weight per day

3. Supplement Support

• Omega-3 fatty acids → Omega 1300

• Vitamin K2 + D3 → supports arterial elasticity and prevents calcification

• CoQ10 → CoQ10 Omega for mitochondrial energy

• Magnesium → regulates vascular tone and prevents calcification

• Sulforaphane → Detox 2.0 for antioxidant support

4. Peptides to Support Vascular Health

• MOTS-c → improves endothelial function, mitochondrial efficiency, and insulin sensitivity

• BPC-157 → accelerates microvascular repair, tissue healing, and nitric oxide signaling

• Thymosin Beta-4 (TB-500) → supports vascular regeneration

• Epithalon → modulates inflammation and vascular aging

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ABI in the Broader Picture of Cardiovascular Prevention

The ABI should be interpreted alongside other cardiovascular risk markers like:

• ApoB and LDL-P

• High-sensitivity CRP

• Lipoprotein(a)

• Homocysteine

• Insulin and fasting glucose

• Coronary calcium score (CAC)

• Carotid IMT or plaque imaging

ABI adds predictive value to traditional risk models like ASCVD and should be included in any comprehensive cardiovascular evaluation.

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When ABI Results Are a Wake-Up Call

Many people don’t experience leg symptoms until PAD is advanced. By the time leg pain or wounds develop, there may be critical limb ischemia, requiring surgery or amputation.

An abnormal ABI should never be ignored. It may be the first and only sign of life-threatening arterial disease.

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Summary: Why the Ankle-Brachial Index Matters

Benefit	Why It Matters
Early detection of PAD	Prevents limb loss and guides vascular care
Predicts heart attack and stroke	ABI <0.90 = 4–6x risk of future events
Simple, fast, and non-invasive	Can be done in office with immediate results
Monitors treatment effectiveness	ABI can improve with proper care
Identifies high-risk patients	Even when cholesterol is “normal”

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Call to Action

If you're over 50, have risk factors like smoking or diabetes, or experience leg symptoms—don't wait. An ABI test is fast, painless, and incredibly informative.

At Revolution Health & Wellness, we include ABI testing in our cardiovascular evaluations. If your ABI is abnormal, we’ll help you build a personalized plan to reverse the damage and protect your heart.

Schedule your ABI test today and take control of your vascular health.

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References

1. American Heart Association. "Ankle-Brachial Index (ABI)."

2. Hiatt WR, et al. "Atherosclerosis and peripheral artery disease." NEJM.

3. Aboyans V, et al. "Measurement and interpretation of the ABI." Circulation.

4. Criqui MH, et al. "The ABI and the risk of cardiovascular events." JAMA.

5. Gerhard-Herman M, et al. "Guidelines for the management of PAD." AHA/ACC.

6. Hirsch AT, et al. "Peripheral arterial disease detection, awareness, and treatment in primary care." JAMA.

7. Wang Y, et al. "MOTS-c: a new player in vascular aging." Front Aging.

8. Jeong J, et al. "BPC-157 and angiogenesis in wound healing." Biomed Pharmacother.

9. Ross R. "Atherosclerosis—an inflammatory disease." NEJM.