It’s puzzling when an apparently healthy person suffers a heart attack or stroke, but a new type of blood test may pick up those at risk, a new study finds.

Cardiovascular disease – primarily heart attack and stroke – are the nation’s Number 1 killer, claiming more lives than all forms of cancer combined.

Most people who suffer heart attacks have coronary heart disease, or at least one or more major risk factors for it, the American Heart Association says

But heart attacks can occur in people who don’t have coronary heart disease, and even in those with normal or low LDL-cholesterol levels, the so-called “bad” cholesterol, researchers at the Mayo Clinic say.

In this study, they used a blood test that is already on the market and measures plasma ceramides, a class of lipids that are highly linked to cardiovascular disease processes.

Ceramides are different than cholesterol, which gathers and causes a clog in the arteries. They are more active, attracting inflammatory cells and promoting clotting.

Blood clots are responsible for the most heart attacks and strokes.

The study found that individuals with the highest levels of blood ceramides were found to have a three-to-four times greater risk of having a cardiovascular event compared with those with the lowest ceramide score, regardless of their LDL cholesterol level or the presence of a blockage in the heart's arteries.

"There is a need to identify patients at increased risk for cardiovascular events so that we can test strategies to prevent those events. This test seems to provide such information," says Dr. Allan S. Jaffe, the senior author of the study, which is to be presented at the American College of Cardiology's 66th Annual Scientific Session in Washington, D.C.