Heart Scans Miss the Start: REACT Shows Silent Plaque Begins in Neck and Legs

Cardiovascular disease kills mainly through heart attack and stroke, and about 20 million deaths each year are largely driven by atherosclerosis , the fatty and inflammatory thickening of artery walls. Think of it like scale inside an old pipe: LDL cholesterol quietly deposits in the vessel lining for years without symptoms. A nutrition-focused clinician calls the new REACT results a turning point because looking only at the heart may mean looking too late.

REACT: A Silent Plaque Atlas in 16,000 People

REACT-DETECT enrolled 16,808 adults aged 18 to 70 in Denmark and Spain with no known atherosclerotic disease. Each person received imaging in three beds: three-dimensional ultrasound of the carotid arteries, three-dimensional ultrasound of the femoral arteries, and coronary CT angiography plus a calcium scan for the heart. The core set of 13,186 participants with complete three-territory imaging now forms the most complete map of silent disease across adult life. The work, supported by up to 23 million euros from the Novo Nordisk Foundation, was presented as a Hot Line at ESC Congress 2026 and published the same day in the New England Journal of Medicine.

The headline is prevalence. Overall, 57.1 percent had plaque; 63.4 percent in men and 50.9 percent in women. The age gradient is steep: about 1 in 13 people aged 18 to 29 had plaque, rising to about 9 in 10 aged 60 to 70. In the youngest band the figures were 8.7 percent in men and 6.7 percent in women. Men ran 5 to 10 years ahead of women; in women the steepest rise fell between ages 40 and 60, roughly the menopause transition . Because the study is cross-sectional, it cannot prove menopause itself caused that rise.

Why Plaque Starts in Neck and Legs in the Youngest

The most striking pattern is geography. Among 18 to 29 year olds with plaque, almost everyone had disease confined to the periphery, the yellow area in the published figure. In the 30s the vast majority still had only peripheral disease, and isolated coronary plaque remained a minority. That peripheral dominance persisted for women through their 40s. In men in their 40s, 60 to 70 percent had any plaque, yet about half remained periphery-only. By the 50s and 60s coronary involvement became common in men, while in women the picture stayed about half and half even at 60 to 70. In short, a clean coronary scan does not mean clean arteries elsewhere.

There is a mechanistic logic. Peripheral arteries experience low shear stress at bifurcations, favoring lipid deposition. REACT supports a systemic view: 82.0 percent of those with coronary plaque also had carotid or femoral plaque, versus 41.5 percent of those without coronary plaque. Isolated coronary disease was uncommon, while isolated peripheral disease was common. Scanning only the carotid also misses disease: 18 percent of those with femoral plaque and no carotid plaque would be labeled differently if only the neck was examined.

Why a Clean Heart Image Is Not a Guarantee

Three paradigm shifts frame this story. First we waited for symptoms, then we moved to risk-factor estimates. The calcium score then became popular, and a zero score on social media was read as all clear, especially in the 30s and 40s. Yet calcium is a late, hardened stage; soft plaque can rupture without calcium and a heart attack can occur with a zero score. Next, coronary CT angiography improved sensitivity by showing both calcified and noncalcified plaque. REACT now shows an even earlier window: peripheral buildup can run for years before anything is visible in the heart. Classic scores such as SCORE2 identified only a small share of those who actually had silent plaque in REACT.

The blind spot is sharpest in younger adults. Among 30 to 39 year olds with coronary plaque, about 42 percent of men and 48 percent of women had no detectable coronary calcium. The proportion fell with age but stayed relevant across the range. The distinction matters: calcium scoring detects calcified plaque, while angiography detects both calcified and noncalcified forms. So a zero calcium score does not rule out early coronary atherosclerosis, especially in young adults. A prudent risk model avoids reassurance based on calcium alone.

How the Periphery Can Be Screened: Ultrasound and a Simple Ankle Test

In REACT the heart was examined with CT while the neck and legs were examined with ultrasound, and the authors propose that portable ultrasound in the hands of any health professional could become a standard early screening tool. In clinics the CIMT measurement, carotid intima-media thickness, compares wall thickness to age norms and flags plaque, often defined as a focal thickening more than 50 percent thicker than surrounding wall or exceeding 1.5 millimeters. Earlier guidance noted that CIMT and carotid plaque can refine risk in intermediate-risk adults. Advantages are clear: no ionizing radiation, low cost, fast, repeatable. Limits are also clear: operator dependence and no single bed captures all disease.

A simple home idea is the ankle-brachial index . Think of comparing pressure in two taps: a narrowed pipe shows lower pressure downstream. Lying flat, measure systolic pressure in both arms and take the higher as reference; then measure systolic pressure at each ankle with the same cuff and divide the ankle value by the arm reference. A normal range of 1.0 to 1.4 suggests no meaningful flow limitation. 0.9 or below is abnormal and suggests leg artery blockage. 0.9 to 1.0 is borderline ; above 1.4 suggests stiff, incompressible arteries , often seen with diabetes or advanced kidney disease. Because small plaque may not affect flow, a normal result does not exclude early disease; anyone with symptoms needs a clinical check even if the number looks normal.

What now? REACT plans a randomized second phase from 2027 to 2032 to test whether imaging-guided, personalized prevention halts systemic progression and reduces heart attacks and strokes better than current practice. Teams are extending validation to India, Singapore, Tanzania and Mexico, building on the earlier PESA-CNIC-Santander cohort. In practice, this does not mean every healthy 25 year old needs a scan; those with family history , hypertension, high cholesterol or smoking can discuss a carotid or femoral ultrasound with their clinician. Lifestyle remains foundational: tobacco-free living, Mediterranean-style eating, regular movement and healthy weight. Imaging marks a move from estimating risk with scores like SCORE2 to directly detecting disease, opening a more targeted and more personal prevention window.