Design in a fish bowl

Woburn, MA--Of all the industries where design engineers toil, few draw as much open scrutiny as the medical field. Even after the design is perfected, engineers must wait many months--and sometimes many years--before government regulators declare a medical device safe and effective for commercial use.

"We're still waiting on pins and needles for FDA approval of our electrical LVAS (left ventricular assist system)," says engineer Vic Poirier, president of the Massachusetts-based Thermo Cardiosystems. The 1992 Design News Engineer of the Year, Poirier has spent most of his career designing implanted pumps that assist hearts weakened by disease.

In 1994, the FDA approved the commercial sale of an air-driven LVAS developed by Poirier and his colleagues, and more than 1,000 of the devices have been implanted in patients as a "bridge to transplant." Without such a device, many of these patients would die, since only about 2,000 natural hearts are available annually.

The electric-powered LVAS, which offers patients more mobility than the air-driven device, has already received the CE mark in Europe, allowing its use in all European Community countries. But here in the U.S., despite nearly $50 million for engineering work, clinical trials, and data acquisition, Thermo Cardiosystems still awaits FDA approval. "They are asking for an incredible amount of data," notes Poirier. "Their engineers want to understand this device as well as we do, and that's a good thing."

But while he respects FDA's diligence, Poirier, like other medical inventors, gets frustrated with the impact that delays may have on patients. The electric-powered LVAS has been implanted in 400 patients under an investigational device exemption (IDE), and it has kept many of them alive as long as two years as they await transplants. In about 10% of the cases, such as in hearts weakened by viruses, LVAS support has allowed the condition of the natural heart to improve to the point where the implant can be removed.

Across the country in San Jose, CA, Symphonix Devices, developer of a revolutionary new hearing aid, is also playing the waiting game. It, too, has received Europe's CE mark for the Vibrant soundbridge(reg), a technology that eliminates annoying acoustic feedback, thanks in large part to a patented Floating Mass Transducer mounted on a bone in the middle ear. The inventor, Geoffrey Ball, recently received the Grand Prize for his device in our annual Excellence in Design Contest.

While the new hearing aid can now be sold in Europe, the technology must still complete clinical trials in the U.S. The company is hoping for FDA approval in late 1999, with commercial sales by the end of the year 2000.

"Typically, for a Class III device, which is the most complex category, you are looking at a 3- to 5-year process before you receive FDA's premarket approval," notes Mike Crompton, regulatory affairs VP for Symphonix.

Crompton and Ball say FDA over the last two years has become more proactive in dealing with companies and has reduced delays by faxing questions associated with a company's IDE application. The agency also has promulgated new "humanitarian use" exemptions, which give patients access to a new technology prior to formal FDA approval.

Even so, design engineers who choose sophisticated medical technology as their field must be prepared for a large dose of delay and government fact-finding. Yet this very scrutiny, says Ball, "can make you a better engineer." Adds Poirier of Thermo Cardiosystems: "It's very satisfying to do solid engineering while helping people live in less pain. You can go home and feel good about yourself."