What we're trying to do is isolate the trouble spots in the body, and then analyze the blood flow. By doing this we've come up with a lot of interesting observations. Ku whips out a marker and draws on a board in his office the intersection of two arteries as it occurs in the human neck, which is a frequent trouble spot for heart disease. Arteriosclerosis, the hardening of the arteries, occurs where blood flows slowly, and cholesterol-filled pockets of plaque build, he explains. Bioengineers analyze exactly why and how this occurs, using the same principles that are more conventionally used to study air flow over an airplane wing.
Engineers rely on plexiglas models to reconstruct blood flow.
They measure flow with lasers, ultrasound, and magnetic resonance imaging techniques and they apply engineering principles to cell biology. Through bioengineering techniques, scientists have discovered that blood flow actually alters the structure of endothelial cells, which line the insides of arteries. Ku illustrates the point by playing a video cassette that shows an artery where blood flow is so poor that it oscillates back and forth. Suddenly, the patient exercises, and blood rushes through the veins, clearing out the built-up plaque particles. Heart disease isn't well understood.