New Study of 16,000 People Reveals Heart Scans Miss Plaque Growing for Decades (It Shows Up in Your Neck and Legs First)

Getting a heart scan to check for plaque might seem like the ultimate preventive move against cardiovascular disease.

But groundbreaking research published in the New England Journal of Medicine suggests doctors—and patients—may be looking in the wrong place entirely.

The study of 16,000 symptom-free individuals revealed something startling: arterial plaque often begins growing decades before anything shows up in heart scans.

Even more surprising? In younger people, plaque typically appears first in arteries outside the heart—particularly in the neck and legs.

Plaque Starts Earlier Than Anyone Expected

Heart disease remains society’s leading killer, which explains why so many people pursue coronary calcium scores and other cardiac imaging tests. The goal is straightforward: detect blockages before they trigger symptoms or cause heart attacks.

However, this new research challenges conventional screening wisdom. Scientists examined 16,000 people with no cardiovascular symptoms or diagnosed heart disease and discovered that 57% already had detectable arterial plaque.

Age proved to be a significant factor. By their 60s, over 90% of participants showed evidence of plaque buildup. But even among the youngest cohort—individuals aged 18 to 29—between 5% and 10% already had measurable arterial deposits.

Men consistently showed higher rates of plaque across all age groups compared to women, though both sexes demonstrated concerning patterns of early disease development.

The Peripheral Pattern: Where Disease Really Begins

Here’s where findings get truly eye-opening. In younger individuals—those in their 20s, 30s, and even 40s—plaque rarely appeared in coronary arteries first.

Instead, deposits accumulated in what researchers call “peripheral territories”: the carotid arteries of the neck (which supply blood to the brain) and femoral arteries of the legs.

The Age-Based Progression

Among 18-29 year-olds with detectable plaque, nearly all showed deposits only in peripheral arteries—nothing in the heart. Their 30-something counterparts followed similar patterns, with the vast majority having exclusively peripheral plaque.

Even reaching the 40s, most women with plaque had it only in peripheral locations. For men in their 40s, approximately half showed peripheral-only deposits despite 60-70% having detectable plaque somewhere.

Only after age 50 did cardiac plaque become common in men. For women, peripheral predominance continued—even in their 60s, roughly half still showed only non-cardiac arterial disease.

Why Heart Scans Miss Early Disease

The implications reshape cardiovascular screening paradigms. Many people receive completely clean heart scans while actively developing plaque in carotid or femoral arteries.

Disease silently progresses for decades, undetected by coronary-focused imaging. Eventually, plaque spreads to cardiac arteries—but by then, atherosclerosis has established a significant foothold.

This represents merely the latest shift in cardiovascular thinking. Previous generations waited for symptoms like chest pain before seeking medical attention. Then physicians realized symptoms emerge only after decades of disease progression, prompting preventive approaches.

Calcium scoring gained popularity next, with some younger adults celebrating zero scores on social media. But medical understanding evolved again: calcium represents a relatively late-stage marker, and substantial plaque—even heart attacks—can occur with zero calcium scores.

CT angiography offered improvements by detecting both calcified and soft plaque, providing greater sensitivity. Now science reveals even sophisticated cardiac imaging can miss years or decades of peripheral arterial disease development.

How To Detect Peripheral Plaque

The study researchers used ultrasound for peripheral arteries (neck and legs) and CT angiography for cardiac vessels. For those with cardiovascular risk factors, doctors may order carotid ultrasound examinations.

These tests, sometimes called CIMTs (carotid intima-media thickness), measure arterial wall thickness and compare results against age-appropriate norms. They can identify detectable plaque and assess whether wall thickness suggests disease.

Femoral artery ultrasounds represent another option when family history or risk factors warrant investigation. Not every healthy 25-year-old requires these tests, but appropriate screening can catch disease before cardiac involvement develops.

The Free At-Home Screening Test

For leg arteries specifically, a simple home test called the ankle-brachial index (ABI) provides preliminary information about blood flow obstruction. While not highly precise, it offers useful first-pass screening without cost or invasiveness.

Here’s how to perform an ABI test:

1. Lie flat on your back with a blood pressure cuff
2. Measure blood pressure on both arms (take the systolic/upper number from each)
3. Use the higher systolic value between arms as your reference
4. Place the cuff around one ankle and measure blood pressure
5. Divide the ankle systolic number by your arm reference number
6. Repeat with the other ankle

For example: if arm readings are 120/60 and 125/60, use 125 as the reference. If ankle pressure reads 125/60, divide 125 by 125, equaling 1.0.

Understanding Your Results

• 1.0 to 1.4: Normal range—suggests no significant arterial blockage affecting blood flow
• 0.9 or lower: Abnormal—indicates probable arterial blockage in legs
• 0.9 to 1.0: Borderline—arteries may be narrowing but haven’t significantly reduced blood flow yet
• Above 1.4: Suggests stiff, calcified arteries (often seen with diabetes or advanced kidney disease)

Important Limitations and Considerations

The ABI test only detects meaningful obstruction. Small amounts of plaque won’t trigger abnormal readings, so normal ABI results don’t guarantee plaque-free arteries.

Anyone experiencing symptoms or possessing strong reasons to suspect peripheral arterial disease should pursue professional medical evaluation regardless of home test results.

This research underscores a crucial reality: cardiovascular disease often begins its silent march decades before traditional cardiac screening detects problems. By the time coronary plaque appears, peripheral arteries may have accumulated years of damage.

For individuals with family history, risk factors, or concerns about cardiovascular health, discussing peripheral artery screening with healthcare providers may prove more revealing than focusing exclusively on cardiac imaging. Early detection in neck or leg arteries could provide the intervention window that heart-only screening misses entirely.