Advances in mechanical circulatory support at Mayo Clinic
When Barney B. Clark, D.D.S., signed the 11-page consent form to become the world's first recipient of a permanent total artificial heart (TAH) in 1982, he did so with the hope that, regardless of the outcome, he would be helping patients with advanced heart failure by promoting a technology that could one day save many more lives.
Three decades later, more than 25,000 patients have been supported on a mechanical circulatory device, either as a bridge to transplant or as destination therapy. Mayo Clinic's surgical director of mechanical circulatory support (MCS), Lyle D. Joyce, M.D., Ph.D., has been a part of this revolution from the beginning. He was one of the surgeons who performed that first implant in Salt Lake City.
The field of MCS has come a long way since Dr. Clark was supported for 112 days on a biventricular pulsatile device that was powered by a controller the size of a washing machine. In the current era, smaller continuous-flow left ventricular assist devices have markedly improved quality of life for patients with MCS.
TAH as a bridge to transplant
Nevertheless, for approximately 5 percent of patients with advanced heart failure, contemporary assist devices, which support only the left ventricle, fail to address the problem of biventricular failure. For these patients, the TAH has emerged as a reliable strategy for successfully bridging patients to transplant at Mayo Clinic.
The current device was developed in response to the size limitations posed by the original 100 cc Jarvik-7 artificial heart, which was implanted in Dr. Clark. Originally dubbed the "Jarvik-7-70" for its smaller 70 cc ventricle, this pump was implanted successfully for the first time by Dr. Joyce in 1985 as the first long-term mechanical support device implanted in a woman.
While the pump technology remains virtually identical to the pneumatically driven Jarvik device, the external components have undergone a dramatic upgrade, with advances in computer technology permitting a much smaller controller for the device. One of the primary quality-of-life limitations of the TAH for Dr. Clark involved the controller, which was approximately the size of a washing machine.
Today's controller fits in a small backpack and can be carried by the patient, permitting a full range of activities. The Freedom portable driver (SynCardia Systems Inc.) received Food and Drug Administration approval in July 2014, enabling patients to return home while waiting for a donor organ. As of September 2014, the TAH has been implanted in a dozen patients at Mayo Clinic's campus in Rochester, Minnesota, with half of the patients successfully receiving transplants and two patients expiring on support.
Dr. Joyce's son, David L. Joyce, M.D., has recently joined the Division of Cardiovascular Surgery at Mayo Clinic's campus in Rochester and is also a member of the MCS team. He put this accomplishment in perspective: "The fact that we currently have more than 100 patients walking around in the community on some form of mechanical support is a testimony to the teamwork and technical expertise of the cardiologists, anesthesiologists, surgeons, ventricular assist device coordinators, engineers, perfusionists, nurses and other professionals that compose our group."
For Dr. Lyle Joyce, the success of the MCS program represents the fulfillment of an improbable dream that started in Texas over 30 years ago when he was working on some of the early prototypes in the laboratory of Michael E. DeBakey, M.D. "When you think about the rivalry that existed in Houston during the early days of the TAH, it's truly remarkable to have a team at Mayo Clinic that combines the unique gifts of every member of the group."
For the Drs. Joyce, the opportunity to collaborate as surgeons within the same subspecialty represents a rare occurrence, given the lengthy training period that is typical for cardiac surgeons. As Dr. David Joyce says, "One of the nice things about having a father who is a leading expert in your clinical area of interest and a sister (Sheri Crow, M.D., with pediatrics and critical care medicine at Mayo Clinic's campus in Rochester) who has published extensively in the field of MCS is that you can almost host your own CME event right at the dinner table."