First continuous-flow total artificial heart transplant performed at THI

Doctors at the Texas Heart Institute (THI) at St. Luke's Episcopal Hospital (SLEH) have successfully implanted the first continuous-flow total artificial heart in a desperately ill patient facing imminent death.

On March 10, 2011, Drs. Bud Frazier and Billy Cohn removed the heart of 55-year-old Houstonian Craig A. Lewis and replaced it with the artificial heart, which had been developed at THI over the last five years in collaboration with industry and funded by grants from the National Institute of Health and the Dunn Foundation. 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 total artificial heart consists of 2 turbine-like blood pumps implanted to replace the 2 sides of the explanted heart. The turbines used in Mr. Lewis's device were modified left ventricular assist devices (LVADs) manufactured by Thoratec Corporation (Pleasanton, Calif.) and approved by the 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. 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 two weeks before doctors decided to try the experimental mechanical heart.

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.

"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: Texas Heart Institute