Successful Implantation of a Continuous-Flow Total Artificial Heart in a Patient at The Texas Heart Institute

Drs. Billy Cohn and Bud Frazier at the Texas Heart Institute were faced with a patient last March who’s heart was about to succumb to the point that even a left ventricular assist device wouldn’t be sufficient to keep him alive. Described as a story of “two visionary doctors from the Texas Heart Institute who in March of 2011 successfully replaced a dying man’s heart with a ‘continuous flow’ rotor-driven device of their own design, proving that life was possible without a pulse or a heartbeat,” the film was directed by Jeremiah Zagar, whose feature-length documentary “In A Dream” was nominated for two Emmy’s in 2010.

HOUSTON, TX. (March 23, 2011) –  Doctors at the Texas Heart Institute (THI) at St. Luke’s Episcopal Hospital (SLEH) have successfully implanted the first continuous-flow device that mimics what might be considered a total artificial heart in a desperately ill patient facing imminent death. Because the implanted pumps provide the blood flow that the sick heart cannot, they act as a total artificial heart.

On March 10, 2011, Drs. Bud Frazier and Billy Cohn implanted the 2 approved devices into 55-year-old Houstonian Craig A. Lewis. These devices were used in a last attempt to save his life.

Mr. Lewis had a rare condition called cardiac amyloidosis, a disease in which the heart is infiltrated by an abnormal protein produced elsewhere in the body. Patients with this affliction are not candidates for heart transplantation because the amyloidosis would probably recur in the transplanted heart.

The continuous-flow device consists of 2 turbine-like blood pumps implanted to replace the 2 sides of the patient’s removed heart. These 2 pumps act as a man-made substitute for the natural heart. The left ventricular assist devices (LVADs) used are manufactured by Thoratec Corporation (Pleasanton, Calif.) and were approved by the US Food and Drug Administration in January 2010 for assisting the failing left ventricle (the heart’s main pumping chamber) in patients suffering from terminal heart failure. The turbine pumps used in Mr. Lewis’s device were approved left ventricular assist devices that were modified for integration in a 2-pump system.  The devices were used in what is called an off-label use, that is, a use for something other than an originally intended indication. The FDA allows physicians to make decisions to use devices off-label in cases when they are clinically deemed the best therapy or, in this case, the only chance the patient has for meaningful survival. Mr. Lewis was not a candidate for an assist pump because his left ventricle was too badly involved with amyloidosis. His right ventricle had also failed.

Mr. Lewis had been supported by an external blood pump, a dialysis machine, and a breathing machine for 2 weeks before doctors decided to try this approach.

Because the device produces continuous flow, Mr. Lewis does not have a heartbeat, or a pulse. An EKG records no rhythm because the heart has been removed. Extensive research performed at the Cullen Cardiovascular Research Lab has shown that this unusual physiology is well tolerated by mammals. Based on their results over the last 5 years, Drs. Cohn and Frazier believed that this device was an option for Mr.Lewis. Less than one week after the device’s implantation, Mr. Lewis was able to sit up in bed and speak with family members.

The Texas Heart Institute has played a pivotal role in the development of implantable blood pumps to treat end-stage heart failure. Under Dr. Frazier’s leadership over the last 40 years, many of the devices currently in clinical trials were first tested and perfected at THI. The newer generation of continuous-flow, turbine-like pumps—first introduced 10 years ago—are smaller, quieter, and much more durable than their pulse-producing predecessors. These technically sophisticated pumps have accelerated the progress in the field of implantable devices. They also gave Frazier the idea for a continuous-flow total artificial heart. THI has been working on developing a continuous-flow total artificial heart over the last 5 years in collaboration with industry and funded by grants from the National Institutes of Health and the Dunn Foundation.

“This really is medical history in the making. The demonstration that one can support the human cardiovascular system with 2 implanted continuous-flow pumps is remarkable and very encouraging. With this new concept in cardiac replacement, we are much closer to realizing a meaningful off-the-shelf replacement,” said Dr. James T. Willerson, THI president. “The Texas Heart Institute is extremely proud of Drs. Bud Frazier and Billy Cohn and their entire team. This is an impressive step forward, following in the legacy of Dr. Denton Cooley, who in 1969 first implanted a prototype artificial heart in a human with a severe heart injury.”

Added Dr. Cooley, founder of THI: “Forty years ago the first total artificial heart was implanted here in a patient dying of advanced heart failure. The device served as a bridge to cardiac transplantation, maintaining the patient’s life until a donor heart was procured. Since then, a major focus of research at THI has been the development of a total mechanical heart that could overcome some of the problems presented by the previous pulsatile devices, including patient discomfort. The continuous-flow design of this device promises a major advance in the effort to replace the heart in patients with terminal cardiac failure. I applaud Dr. Frazier and Dr. Cohn for their contributions. This is a further milestone.”

Source:http://texasheart.org/AboutUs/News/2011-03-23news_tah.cfm

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