Take a look at this:
"After a year, the research participants had an angiogram—a special X-ray that shows the trickle of blood that gets through to the heart—and the results were compared to ..."
The author is talking about the arteries inside the heart; because the subject matter is heart disease. So shouldn't it just say:
"the trickle of blood that *gets through the heart"?
I don't get it!