Dr. Steven Feinstein’s face lit up almost as much as the image of a patient’s beating heart he gazed upon in a hospital room the other day.
“It’s just like turning on a light bulb,” Feinstein said as he beamed. “You can clearly see the walls of each chamber, see the blood flowing.”
It’s been 15 years since Feinstein, a cardiologist at Rush-Presbyterian-St. Luke’s Medical Center in Chicago, first developed his concept to give physicians a simple and relatively inexpensive way to look at a patient’s heart to diagnose cardiac problems more quickly and accurately. Now that idea could soon be a product widely available to physicians.
Its backers estimate the initial market for the new product could be $200 million, and it could help patients diagnose disease earlier and more accurately, helping patients and reducing cost of care. If that comes to pass, it will represent a major victory for the 47-year-old director of Rush’s echocardiography lab whose medical research laid the groundwork for the technology.
Feinstein’s concept was to enhance echocardiography, the technology used by physicians to assess how well a patient’s heart is working. Echo equipment transmits sound waves through a patient’s body to the heart and picks up the waves that bounce back to create images of the heart as it is beating.
Doctors scrutinize these images to determine how efficiently the heart is pumping blood, whether heart muscles are adequately nourished and other vital information.
Echocardiography is attractive because the equipment can be rolled into a hospital room and the transducer placed against a patient’s chest without moving him from the bed. It doesn’t require hospitalization and is often done in a doctor’s office.
But the gray and fuzzy images produced by echocardiography often leave physicians guessing and require sending the patient for other more expensive and invasive tests.
Feinstein’s concept was simple enough: If millions of tiny bubbles were injected into the patient’s bloodstream, the bubbles would amplify the signal produced by sound waves. Now tests suggest this idea works well enough to aid physicians significantly in diagnosing heart ailments.
Within a few weeks, the U.S. Food and Drug Administration is expected to approve a contrast agent called Optison for use with echocardiography, said Stephen Keane, director of business development for Molecular Biosystems Inc. of San Diego, the product’s developer.
But as is typical, getting from even a relatively simple idea to a useful product has been difficult.
For one thing, the micro-bubbles in the process technically aren’t bubbles at all, but microspheres made with human albumin that have semi-rigid shells and are about half the size of red blood cells. These tiny spheres are far too small to cause a patient any harm and are harmlessly absorbed by the body soon after injection.
The company that turned Feinstein’s idea into a product, the publicly traded Molecular Biosystems, launched a product a few years ago that won FDA approval, but failed to impress physicians in the marketplace. The problem is that the microspheres persisted in a person’s bloodstream for only about 30 seconds, not long enough to improve an echocardiogram’s diagnostic value.
“It’s been a commercial disappointment,” said Keane. “Sales of $1 million a year wasn’t what we were looking for. But it did give us proof of concept, and that was important.”
The new product uses an inert gas instead of air inside the microspheres, which themselves have been made more resilient so that the contrast agent persists for about five minutes after injection in a patient, enough to meet a physician’s diagnostic needs.
Advances in the echo equipment itself have also been necessary.
Keane said that physicians perform an estimated 14 million echocardiograms a year, and 15 to 20 percent are too unclear to be helpful. If the new contrast agent Optison is used only in those cases, he said, that would represent a $200 million annual market.
And once doctors start using the agent, they will likely find new applications.
Dr. Philip Liebson, a Rush professor of preventive medicine, said he hopes to learn if echocardiography with Optison can reliably determine if a patient’s cardiac chamber wall is becoming thickened even before symptoms appear.
“If we could make more precise prognoses in patients with seemingly normal hearts,” said Liebson, “we could determine who is at high risk and intervene sooner.”
The technology also could well help emergency room physicians quickly determine if a patient who complains of chest pains actually is at risk of a heart attack, said Dr. James Macioch, director of stress echocardiography at Rush.
Despite the expectation that the FDA will soon approve Optison, tests will continue for some time to find the best ways to use it, said Joanne Sandelski, manager of the echocardiology lab at Rush.
“We know that if you turn up the power too much, you crush the microspheres,” she said.
That finding intrigues Feinstein.
“Suppose you loaded these microspheres with a toxic agent instead of an inert gas,” he said. “You could inject it in the blood and then direct high-powered sound waves at a tumor so the spheres would burst as they past through, releasing the toxin to kill tumor tissue.
“It could be a new drug delivery system. But that’s futuristic. The important thing is that this is ready right now to help diagnosis in heart patients.”
