The Next Generation of Artificial Heart Technology

It fits easily into the palm of your hand, is easy to install, is mechanically reliable, and the ones that have used it swear that it's a dream come true. Is it some new household appliance or computer add-on?

If you answered "yes," get ready for a surprise: it's the latest generation of artificial heart technology!

According to a recent report in the New England Journal of Medicine this new technology, known as a Left Ventricular Assist Device, (LVAD) appears to be superior to the artificial heart currently approved to treat advanced heart failure in the United States.

The report, summarizing the findings from a randomized study comparing two fundamentally different design paradigms, found that patients receiving a device using a newer design paradigm were twice as likely (58% vs 24%) to be alive two years later than those who received the currently-approved artificial heart.

Heart failure, sometimes called congestive heart failure or "CHF," is a condition in which the heart is no longer able to pump a sufficient volume of blood to meet the body's oxygen and nutritional requirements. Although medical treatment is effective in many cases of heart failure, sometimes this disease will progress until the only remaining alternative will be a heart transplant. Unfortunately, many patients that are awaiting a donor heart will die while waiting for one to become available.

Surgically implanted artificial hearts have long been associated with complications such as stroke, infection, abnormal formation of blood clots, and reoperation for device failure malfunction. With the current design of the artificial heart, many complications are thought to arise from the devices' reliance on "pulsatile flow." In pulsatile flow, the artificial heart's chambers are allowed to fill and are then rapidly compressed to eject blood into the body's circulatory system.

Although it is technically not an artificial heart since the natural hear itself is not replaced, the newer device is based on "continuous flow" in which a small corkscrew-like device spins rapidly to propel blood into the patient's aorta where it is then "carried along" by blood that is ejected from the heart's main pumping chamber, the left ventricle. Its small size, and the fact that the patient's natural heart isn't removed, dramatically reduces the risk of surgical complications.

In the study 200 patients with end-stage heart failure, but not eligible for heart transplantation, were placed in two groups where 134 patients received a continuous flow Left Ventricular Assist Device while 66 received an artificial heart that utilized pulsatile flow. The study then followed each patient for two years, or until death, or a major complication such as stroke or device failure arose. In all categories, including quality of life and patient satisfaction, the continuous flow device matched or exceeded the currently-approved artificial heart.

The LVAD evaluated was the Thoratec Corporation's HeartMate II.

The US Center for Disease Control and Prevention has estimated that the number of hospital admissions due to heart failure increased by more than 20% during the last decade and that 300,000 people die each year as a direct consequence of the disease.

The study, "Advanced Heart Failure Treated with Continuous-Flow Left Ventricular Assist Device," appeared in the December 3, 2009 issue of the New England Journal of Medicine and was funded by a grant from the National Institutes of Health's National Heart, Lung, and Blood Institute.

Note

If the above story caught your interest, take a look at how all this began: a primitive artificial heart, built from a child's Erector Set and a few dollars spent in a local dime store, led to the first open heart surgeries in the early 1950s. Trust me on this one: Sewell's Pump is one of the most fascinating things that I've read in years!