Innovation & Design

A Smaller, Sleeker Heart Pump


Less intrusive and better-designed devices are in the works—and analysts predict profits for the companies that make them

Back in 1982, Barney Clark, a 61-year-old dentist, was implanted with the world's first artificial heart, the Jarvik-7, a cumbersome piece of equipment with complicated external mechanisms. The device, which extended Clark's life for 112 days, required the patient to be hooked up, via hose-like tubes emerging from his chest, to a machine the size of a laundry dryer. The machine supplied bursts of air that helped to pump the mechanical heart.

Today's medical-device designers foresee a more independent existence for patients suffering from heart failure. Just as the designers of popular consumer electronics such as Apple's (AAPL) iPod or Motorola's (MOT) RAZR phone have been able to slim their products to wafer-thinness, medical engineers and consultants are employing similar strategies and innovations to create slimline devices that are genuinely life-enhancing.

The current Holy Grail of heart-device design is an implanted, bio-compatible heart pump that helps an ailing organ (versus fully replacing an organic heart). It's so tiny, quiet, and devoid of complicated, power-churning apparatus as to be virtually undetectable.

A fresh vision of such a device can be found in the Levacor, under development by Oakland, (Calif.)-based WorldHeart (WHRT), named in June, 2006, as one of "50 Companies to Watch" by trade publication Medical Device & Diagnostic Industry (MDDI). WorldHeart's annual sales figures for 2005 reached $11.6 million. Currently, the Levacor is the simplest implantable and—here's the key to its distinctive technology—magnetically levitated rotary heart pump now in feasibility trials (in Europe).

WorldHeart's Initial Goals

Still very much in the development stage, and yet to enter U.S. clinical trials (meaning FDA approval is far off), Levacor was born nearly 15 years ago. Pratap Khanwilkar, vice-president for rotary systems and business development at WorldHeart, says that the initial team—of which he was a member—began by analyzing problems with existing heart-pump technology. (At the time, Khanwilkar's team was working under a different company name, Medquest. World Heart acquired Medquest in 2005.)

"Our goals were to deliver a pump in a package small enough to fit in a range of bodies—teens as well as adults of all sizes. One that wouldn't stop working in a year or two, and could have the potential for long-term use," recalls Khanwilkar, who holds a PhD in bioengineering.

In other words, they sought to create a pump that a patient could, if very young, grow old with—or, if elderly, grow older with—without having to replace it and undergo the stress of repeat surgery. The idea is called "destination therapy" in the medical world.

"The pump would have to be gentle to blood cells, so as not to rupture them, and at the same time vibrate as little as possible and require low power consumption," Khanwilkar adds.

Gradual Improvements

Khanwilkar and his colleagues turned to a technology that no other blood pumps or other heart devices incorporated in the early 1990s: magnetic levitation, which is more typically used for larger engineering projects, such as high-speed power turbines or trains. Khanwilkar and his team reasoned that magnetic levitation "could provide the greatest safety and had potential for high durability," he says, because the parts didn't have to come into contact with each other.

Instead, carefully balanced magnetic fields suspend the rotor so it can move without coming into contact with other parts, eliminating the need for bearings or shock absorbers. This translates into no friction, heat, or wear-and-tear on the pump, meaning the device could last longer.

In the ensuing years, the design team worked with LaunchPoint Technologies, a Goleta, (Calif.) engineering firm, to create the smallest and simplest proprietary magnetic levitation system possible. The objective was to provide a continuous-flow pump with a circular rotor—a single moving part—to push blood from the ailing heart to circulate through the body. Full magnetic levitation, which allows the rotor to suspend fully, also allows for less obstruction for blood flow, thus preventing dangerous clots.

The team relied on mathematical calculations, based on the physics of both blood flow and magnetic levitation, to determine the rates by which blood particles could be preserved as they would move through the pump, and other technical concerns. At first they organized their computations in an Excel spreadsheet until they could reach dimensions that represented a small enough version of the magnetic levitation device.

Then they created CAD models of smooth-surfaced, compact shells, before finally building a physical prototype out of transparent plastic. This ghostly version made it possible to observe liquid flow, which they simulated with a blood substitute.

Smaller Designs

The current version of the Levacor, made from a titanium alloy that is often used in implanted orthopedic devices, is smaller than a typical adult human heart, about the size of an ice hockey puck. It's a quarter of the size of WorldHeart's previous implantable heart pump, and is inserted into the patient's abdomen, with blood entering the pump via the heart's left ventricle and exiting the pump into the circulatory system. Patients must wear a battery pack and electric controller that is strapped close to the body.

The first human to receive a Levacor was a 67-year-old male who took part in the feasibility trials in March, 2006, in Thessaloniki, Greece. The patient was able to climb stairs 50 days after the procedure and is currently living at home. WorldHeart (and LaunchPoint) is also working with the University of Pittsburgh to develop an even smaller version of the device for babies, only 22mm in diameter and 43mm in length.

"[The Levacor] is an elegant and efficient-looking design, one that is compact and bio-compatible," observes MDDI's co-editor, Erik Swain. "It's a real contrast to the public perception of the previous artificial hearts or heart pumps, such as the Jarvik-7."

Improvements Bring Profits

Doctors and patients aren't the only ones who are banking on sleeker, less-obtrusive implanted heart pumps such as the Levacor. Analysts are starting to note that demand for more comfortable, longer-lasting heart-pump devices will start to rise—meaning there could be increased profits for the companies that make them.

In late December research notes, First Albany analyst Jason Mills and J.P. Morgan Securities analyst Taylor Harris both stated that the potential for an implantable device by heart-pump market leader Thoratec (THOR) could grow dramatically, after Medicare unveiled a proposal to expand the list of hospitals authorized to implant the pump.

Thoratec's annual sales figures for 2005 were $201 million. The device in question is the HeartMate XVE, currently the only long-term, implanted heart pump of its kind on the market.

As the American population ages and experiences increasing life expectancy, the need for longer-term heart pumps will surely increase as well. Companies such as WorldHeart could see a booming market for their devices.

The American Heart Assn.'s 2007 heart disease and stroke statistics state that nearly 80 million American adults have at least one type of cardiovascular disease, ranging from high blood pressure to heart failure. Approximately 5 million suffer from heart failure.

The "Medical Consumer"

And industrial designers believe that the look and feel of medical devices is in need of a much-needed makeover to appeal to aging Baby Boomers who are active and youthful. This demographic "wants to live, and demands, a full, rich life. The Boomer market drives research dollars among medical-device companies," observes Allan Cameron, principal designer at Boston consultancy Continuum.

"There's a different driver now: lifestyle. Now we have medical consumers, a market that didn't exist 20 years ago."

The Levacor, with its tiny size and promise for durability, might represent a future niche within the heart-pump market itself. Jeffrey W. Nelson, president of Thoratec's cardiovascular division, says that Thoratec is also developing its own bearingless, magnetic levitation pump, the Heartmate III, though he adds that the company is at least a year away from human clinical trials.

It's clearly too early to predict the widespread, long-term potential of such next-generation, magnetic levitation heart pumps. But the Levacor case study illustrates that medical-device designers, engineers, and doctors are increasingly willing to take the pulse of patients' needs and wants as consumers, taking into consideration factors of lifestyle and longevity while developing ever safer, stronger, and sleeker devices.


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