CAD/CAM Software Used to ModelLifelike Coronary Conditions

Originally Published MPMN May 2003

PROFILE

CAD/CAM Software Used to ModelLifelike Coronary Conditions

Free-form surfacing tool aids in the design of minimally invasive products

by Zachary Turke

Few companies know just how difficult it is to design cardiac treatment devices better than Guidant Corp. (Indianapolis; www. guidant.com). In business since 1994, the company has manufactured a variety of stents, defibrillators, catheters, leads, and guidewires. And while these devices have been successfully employed to treat a number of maladies, the firm wanted to find a way to develop and test new products that didn't rely on living animals and patients. That is why the company turned to VX Corp. (Palm Bay, FL; www.vx.com) for CAD/CAM software it could use to produce heart models so lifelike they could serve as a viable testing alternative.

"We wanted to avoid a situation where the device had to be removed from a living heart because it didn't perform as needed," says Guidant research and development manager David Wolf-Bloom of his company's decision to explore the software option. But he also notes that findingthe right design program to produce the models was no easy task. "Some product designers talk about organic shapes when referring to consumer products, but no manufactured product is as uniquely challenging and oddly shaped as a human organ. There are no standard geometric forms such as you'd start with in a typical solid-modeling program," he says.

It was for this reason that the company decided to try VX's software. Based on a proprietary geometric-modeling kernel, this program supports a combination of solid, surface, and wire-frame design techniques. Coupled with a proximity compliance-tolerancing feature that eliminates tolerance problems, the software allows designers to model free-form complex organic shapes with a very high degree of realism.

Guidant purchased the software and tested it by creating 3-D coronary models from a set of computed tomography scans. After inputting the data, the company was satisfied with the program's ability to model the complex organic shapes of the human heart and its surrounding arterial tree. The company received an additional bonus when it actually went to produce the models. Using built-in features, the program automatically added the required cooling channels and inserts needed to produce the mold and generated the subsequent machine instructions.

Using these instructions, the company successfully produced the new testing aids, which are now used daily at a development facility in Belgium. And according to Guidant, feedback has been uniformly positive. "We're pleased with the degree of realism that we've been able to achieve so far," says Wolf-Bloom. "The next step is to produce a beating heart model to simulate even more accurately the real clinical environment. We expect VX software to help take us there." 

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