Soft Plaque vs. Hard Plaque: What's the Difference?

Plaque has a life cycle. It starts soft, as a buildup of cholesterol in the artery wall, and over the years some of it hardens with calcium. Soft plaque is often the riskier kind, as it is prone to rupture, and in younger people it's usually most of the plaque there is. A calcium score only sees the hardened part, while a coronary CT angiogram (CCTA) sees both.

What's the difference between soft and hard plaque?

Plaque is cholesterol and other material that collects in the wall of an artery. When it first forms, it's soft. With time, parts of it take up calcium and harden. On a scan report you'll see the two kinds called non-calcified (soft) and calcified (hard), and plaque with both is called mixed.

Early on, most plaque is the soft kind. Among 805 healthy adults from families with early heart disease, more than 70% of the plaque in men under 55 was soft, and more than 80% in women under 55. So a calcium score can look reassuring even when much of the plaque simply hasn't calcified yet.

Why is soft plaque riskier?

Soft plaque is newer and less settled, so it's more prone to rupture. If it does rupture, a clot can form on top of it and block the artery. It doesn't have to be large first, either: about two-thirds of heart attacks begin at plaque that was narrowing the artery by less than half.

That doesn't make hard plaque harmless. Calcium is a sign that plaque is present, and the more of it you have, the higher your overall risk. It's simply older and more stable than the soft kind.

How do you find soft plaque?

Finding soft plaque takes a scan that can see the artery wall itself. A CCTA does that with contrast dye through an IV, and it costs more than a calcium score. A calcium score can't see soft plaque at all, so a zero doesn't rule it out: in the Miami Heart Study, 16% of people with a zero had plaque on a CCTA.

A CCTA report tells you where your plaque is, whether it's soft, hard, or mixed, and how much it narrows each artery. If you want exact amounts, AI plaque analysis (Cleerly and HeartFlow Plaque are two examples) measures the volume of soft and hard plaque separately and assigns an overall plaque stage. At Veevo it's an optional add-on. Our CT angiogram guide explains how to read a CCTA report.

Can soft plaque be reversed?

It can shrink, which is the good news here. In a study of more than 3,000 patients, high-intensity statins were linked to less plaque overall and to more of what remained turning calcified. In the GLAGOV trial, adding a second LDL-lowering medicine to a statin shrank plaque more than the statin alone.

Hard plaque is a different story, because it tends to stay. That's why a calcium score can go up while treatment is working: soft plaque is turning into stable, calcified plaque. Our guides to lowering a calcium score and LDL cholesterol go into more detail.

The bottom line

Plaque starts soft and hardens over time. The soft kind is newer, often riskier, usually the bigger share in younger people, and the kind treatment can shrink. A calcium score shows the hardened part, and a CCTA, including the one Veevo offers, shows both; see current prices.