Non-Oncology Applications: 4 of 14

Cardiovascular Disease

Cardiovascular disease includes conditions of the heart and blood vessels, such as heart attack, heart failure, diseases of the heart muscle, irregular heart rhythms, and narrowing or hardening of the arteries.

Blood testing is already very good at one important job here. When heart muscle is damaged during a heart attack, it releases a protein called troponin into the bloodstream. Troponin testing is fast, cheap, available in virtually every emergency department, and extremely sensitive. For that specific question, there is very little room for a new marker to improve on it.

The open questions are the ones current tests handle less well. Researchers would like to know which people with no symptoms are heading toward a heart attack in the next few years, why one person's heart muscle has thickened or weakened, and whether someone with heart failure is starting to deteriorate before they become sick enough to need a hospital stay.

Much of the work looks at short pieces of RNA and cell-free DNA, the loose DNA released by dying cells. Some RNA pieces are produced mainly by heart muscle or the lining of blood vessels, so their levels can give clues about what those tissues are doing. With cell-free DNA, researchers can look at both the total amount in circulation and signs of which tissue released it when the heart or vessels are injured.

The signal from the heart is small compared with everything else in the bloodstream, which makes it difficult to isolate. New markers also have a high bar to clear. Predicting a future heart attack requires following many healthy people for years, and any new test has to add useful information beyond things doctors already measure cheaply, including blood pressure, cholesterol, smoking history, and age. If a marker only repeats what those measures already say, it does not help much.