Peripheral Arterial Disease (PAD) in the Foot: ABI & TBI Screening in Columbus, Ohio

Every year, thousands of Americans lose a leg - not because treatment wasn't available, but because the disease was never caught in time. Peripheral Arterial Disease, or PAD, is one of the most underdiagnosed serious conditions in medicine. It affects more than 8 million Americans, yet up to 75% of those with the disease either have no symptoms or don't recognize them. For patients with diabetes, the number is even more alarming.

As a podiatrist, I see the downstream consequences of undiagnosed PAD regularly: wounds that won't heal, infections that spread, toes that turn dark. What many patients - and even some providers - don't realize is that the foot is where PAD announces itself first. And a podiatrist who knows what to look for, and has the right tools in the office, can catch it before it becomes irreversible.

What Is Peripheral Arterial Disease?

Peripheral Arterial Disease is a form of atherosclerosis - the buildup of plaque (fatty deposits, calcium, and inflammatory cells) inside the walls of arteries - that specifically affects the arteries supplying the legs and feet. As plaque accumulates, the arterial lumen narrows, reducing blood flow to the lower extremities. In advanced cases, the artery may partially or completely block.

The result is a progressive mismatch between the oxygen and nutrient demands of the tissues and the blood supply available to meet them. At rest, the reduced flow may be sufficient. But with activity - walking, standing, climbing stairs - the muscles demand more oxygen than the compromised arteries can deliver, causing the characteristic cramping pain of PAD called intermittent claudication.

In severe PAD, blood flow is inadequate even at rest. This produces critical limb ischemia (CLI) - rest pain, non-healing wounds, and tissue death (gangrene). CLI is a limb-threatening and life-threatening emergency.

Why the Foot Shows It First

The foot and lower leg are the farthest points from the heart in the circulatory system. They are also the most metabolically active - bearing the full weight of the body with every step. This combination makes the foot uniquely sensitive to reduced arterial flow. When circulation is compromised anywhere along the arterial tree - from the aorta to the tibial arteries to the digital vessels - the foot is typically the first place the deficit becomes apparent.

Podiatrists see patients specifically for foot problems, which means we routinely examine the very tissues that PAD affects most severely. A non-healing blister, an ulcer on the toe tip, a nail that looks abnormal, or a patient who mentions their foot "always feels cold" - these are the clues that trigger a vascular assessment in our office.

Symptoms and Warning Signs

PAD exists on a spectrum. Many patients are asymptomatic despite significant arterial narrowing. Others present with classic or atypical symptoms that are frequently misattributed to arthritis, nerve pain, or simple aging. Key warning signs include:

• Intermittent claudication: Cramping, aching, or heaviness in the calf, thigh, or buttock that comes on predictably with walking and resolves with rest. The distance a patient can walk before pain starts (claudication distance) is a useful clinical marker - and it shrinks as PAD progresses.
• Rest pain: Aching or burning pain in the foot or toes that occurs at rest, particularly at night in bed. Patients often describe hanging the foot off the bed for relief - gravity briefly improves flow to the foot. Rest pain signals critical ischemia.
• Cold or pale feet: Reduced arterial inflow lowers foot temperature. One foot noticeably colder than the other, or feet that are chronically cold regardless of ambient temperature, warrants vascular evaluation.
• Wounds that won't heal: Any ulcer or wound on the foot that fails to show meaningful healing within two weeks must be assessed for an ischemic component. Arterial ulcers typically appear on the tips of toes, between toes, or over bony prominences. They are often pale, punched-out, and painful.
• Color changes: Dependent rubor (foot turns red when lowered), pallor on elevation, or dusky/cyanotic coloring of the toes are signs of compromised arterial flow.
• Absent or diminished pulses: The dorsalis pedis and posterior tibial pulses are routinely assessed at every podiatric visit. Absent pulses in a symptomatic patient are a reliable indicator of significant PAD.
• Hair loss, shiny skin, thickened nails: Chronic ischemia causes trophic changes in the skin and nails - hair loss on the dorsum of the foot and toes, thin shiny skin, and dystrophic toenails are common findings.

Who Is at Risk?

PAD shares its risk factors with coronary artery disease and stroke. Patients with PAD have a 3-6x increased risk of myocardial infarction or stroke compared to the general population - making early identification not just a limb-saving intervention, but a potentially life-saving one.

• Diabetes mellitus: Diabetes is the single strongest risk factor for PAD in the lower extremities. Diabetic patients develop PAD earlier, more severely, and in a more distal (below-the-knee, into the foot) distribution than non-diabetic patients. They are also more likely to be asymptomatic due to concurrent neuropathy masking claudication pain.
• Smoking: Tobacco use - current or past - is the second most powerful risk factor. Smoking causes direct endothelial damage, accelerates plaque formation, and promotes arterial spasm. The PAD risk for current smokers is 2-4x higher than non-smokers.
• Age over 50: The prevalence of PAD increases steeply with age - from approximately 5% in those aged 40-49 to over 20% in those over 70.
• Hypertension: Chronic high blood pressure damages the arterial wall and accelerates atherosclerosis throughout the vascular tree.
• High cholesterol (hyperlipidemia): Elevated LDL cholesterol is a primary driver of plaque formation. Statin therapy significantly reduces PAD progression and cardiovascular events.
• Chronic kidney disease: CKD both accelerates atherosclerosis and is associated with non-compressible (calcified) arteries, making standard ABI testing less reliable.
• Family history of atherosclerosis: A first-degree relative with premature heart disease or stroke raises PAD risk.

ABI Testing: The Ankle-Brachial Index

The Ankle-Brachial Index (ABI) is the standard first-line test for PAD. It is non-invasive, painless, requires no radiation, and can be performed in a podiatrist's office in under ten minutes. At Vertex Podiatry, we perform ABI testing in-office with our vascular Doppler system.

How the ABI Test Is Performed

The patient lies comfortably on the exam table. Blood pressure cuffs are placed on both arms and both ankles. Using a handheld Doppler ultrasound probe, we measure the systolic blood pressure at four points:

• Both brachial arteries (upper arms)
• The dorsalis pedis artery (top of the foot)
• The posterior tibial artery (behind the inner ankle)

The ABI for each leg is calculated by dividing the higher ankle pressure by the higher brachial pressure:

ABI = Highest ankle systolic pressure ÷ Highest brachial systolic pressure

Interpreting ABI Results

• ABI ≥ 1.40: Non-compressible (calcified) arteries - the result is unreliable. This is common in diabetic patients. TBI testing is required.
• ABI 1.00-1.39: Normal. No significant arterial disease detected.
• ABI 0.91-0.99: Borderline. May warrant monitoring or further evaluation with exercise testing.
• ABI 0.71-0.90: Mild PAD. Claudication may be present. Aggressive risk factor modification indicated.
• ABI 0.41-0.70: Moderate PAD. Claudication typically present. Vascular surgery referral recommended.
• ABI ≤ 0.40: Severe PAD / critical limb ischemia. Urgent vascular referral required.

TBI Testing: The Toe-Brachial Index

The Toe-Brachial Index (TBI) is a critical complement to the ABI - and in many diabetic patients, it is the more reliable of the two tests.

Why TBI Matters in Diabetic Patients

Diabetes causes medial arterial calcification - a process distinct from atherosclerosis where calcium deposits within the arterial wall itself (not the lumen). Calcified arteries become incompressible: when a blood pressure cuff inflates over them, the artery doesn't collapse, producing an artificially elevated pressure reading. A diabetic patient with severe PAD may therefore have a normal or even high ABI - a false negative that provides dangerous reassurance.

The digital arteries of the toes are significantly less affected by medial calcification, making toe pressure measurement a more accurate indicator of actual distal perfusion in diabetic patients. ABI results ≥ 1.40 (non-compressible arteries) or any situation where the ABI seems inconsistent with the clinical picture is an indication for TBI testing.

How TBI Testing Is Performed

A small, specialized photoplethysmography (PPG) sensor is placed on the first or second toe, and a tiny blood pressure cuff is positioned at the base of the toe. The cuff inflates to occlude flow, then slowly deflates. The PPG sensor detects the return of pulsatile flow, giving us the toe systolic pressure. The TBI is calculated as:

TBI = Toe systolic pressure ÷ Brachial systolic pressure

Interpreting TBI Results

• TBI ≥ 0.70: Normal perfusion to the toes.
• TBI 0.60-0.69: Borderline. Monitoring and risk factor management indicated.
• TBI < 0.60: Significant PAD. Vascular evaluation warranted.
• TBI < 0.30 or absolute toe pressure < 30 mmHg: Critical ischemia. Wound healing is unlikely without revascularization. Urgent vascular referral required.

What Happens at Vertex Podiatry

At our Grandview Heights office, ABI and TBI screening is part of our standard evaluation for patients with diabetes, non-healing wounds, vascular risk factors, or any foot symptoms that suggest compromised circulation. The testing equipment is in-office - there's no referral to a separate imaging center, no scheduling delay, and no additional preparation required on your part.

Here's what a typical vascular screening visit looks like:

• Medical history review: We discuss your cardiovascular risk factors, medications, symptoms, and family history.
• Clinical examination: Assessment of foot pulses, skin temperature, capillary refill, skin and nail changes, and any wounds or ulcers.
• ABI measurement: Performed with our Doppler system while you rest comfortably on the exam table.
• TBI measurement (when indicated): Performed immediately if ABI is elevated (≥ 1.40), absent, or clinically inconsistent.
• Results and next steps: Dr. Golan reviews the results with you directly in the office, explains what they mean, and outlines the recommended next steps - whether that's monitoring, lifestyle intervention, or referral to a vascular specialist.

What Happens After an Abnormal Result?

An abnormal ABI or TBI is the beginning of a care pathway, not the end. Depending on the severity and clinical context, next steps may include:

• Risk factor modification: Aggressive management of diabetes, blood pressure, and cholesterol through your primary care physician or cardiologist. Smoking cessation is the single most important intervention for PAD progression.
• Antiplatelet therapy: Aspirin or clopidogrel to reduce cardiovascular event risk - coordinated with your PCP.
• Supervised exercise therapy: Structured walking programs are a first-line treatment for claudication - they promote the development of collateral circulation and significantly improve walking distance.
• Referral to vascular surgery: For moderate-to-severe PAD, endovascular procedures (balloon angioplasty, stenting) or surgical bypass can restore flow and prevent limb loss. We have established referral relationships with vascular surgery specialists in the Columbus metro area.
• Wound care: For patients with existing ischemic ulcers, specialized wound management is essential - debridement, offloading, advanced dressings, and close monitoring until healing is confirmed.

PAD and Diabetic Foot Ulcers: A Critical Connection

Approximately 50% of diabetic foot ulcers have a significant ischemic component - meaning PAD is either causing the wound or preventing it from healing. In patients with both neuropathy and PAD (neuroischemic ulcers), outcomes are significantly worse than in either condition alone. The combination impairs the sensation that would normally prompt protective behaviors, while simultaneously depriving the tissues of the blood flow needed to fight infection and heal.

For any diabetic patient with a foot wound, vascular assessment is not optional - it is standard of care. Without knowing the perfusion status, wound treatment decisions are made in the dark.

Don't Wait for Symptoms

The most dangerous aspect of PAD is its silence. Diabetic neuropathy masks claudication pain. Sedentary patients never reach the exertion level that triggers claudication. Many patients adapt their activity level so gradually - walking less, resting more - that they never realize their walking distance has shrunk to a fraction of what it once was.

Screening should not wait for symptoms. The American Diabetes Association recommends vascular assessment for all diabetic patients with foot complications. The American College of Cardiology recommends ABI screening for all patients over 65, and for patients 50-64 with diabetes or smoking history. We apply these guidelines proactively at Vertex Podiatry.

If you have diabetes, a history of smoking, hypertension, high cholesterol, or a family history of vascular disease - or if you simply have a foot that feels cold, a wound that won't heal, or pain when you walk - call our Grandview Heights office at (614) 328-5561 or schedule a vascular screening. Ten minutes of testing could change everything.