Long-term success: Stanford's experience in heart transplantation over five decades
by Roxanna Van Norman
March 16, 2022
A study led by researchers at the Stanford Department of Cardiothoracic Surgery found long-term survival after heart transplantation has improved over the last 50 years at the longest-running heart transplant center in the United States.
"Stanford has a decades-long history of pioneering, leading, and advancing the field of cardiac transplantation," said Joseph Woo, MD, the Norman E. Shumway Professor and Chair of the Department of Cardiothoracic Surgery and senior author on the paper. "We wanted to study Stanford’s extensive data in heart transplantation since the first adult heart transplant in the United States performed onsite in 1968 and identify factors contributing to patient outcomes."
Researchers on the study looked at more than 2,600 records, specifically heart transplants performed between 1968 and 2020. Findings from the study showed long-term survival after heart transplantation improved over time, despite increased recipient and donor age, worsening comorbidities, increased technical complexity, and prolonged total allograft ischemia time.
Improving patient outcomes
In the last decades, advancements in immunosuppression medications, improved organ donor procurement and preservation techniques, and post-surgery care management have likely led to improved survival after heart transplantation.
Based on the study, patients who had heart transplants at Stanford in the recent decade between 2007 and 2019 had an increased survival rate at one year. The average age increased from 44 years old in the cohort prior to 1995 to 53 years old in recent years, and, if healthy, would have many years of quality life in front of them.
Stanford expanded its organ procurement and recipient eligibility criteria, providing access for patients to heart transplants and shortening wait times. With increasing experience in donor organ procurement, Stanford adopted techniques in organ preservation to reduce total allograft ischemic time.
In addition, the use of mechanical circulatory support (MCS) technologies has grown in the recent decade. MCS, such as extracorporeal membrane oxygenation machine and ventricular assist device, has provided and prolonged cardiac and respiratory support to patients, as well as a bridge to transplant.
"These advancements helped establish Stanford's pre-eminence in the field of cardiothoracic surgery," said Philip Oyer, MD, PhD, the Roy B. Cohn-Theodore A. Ealasco Professor Emeritus of Cardiothoracic Surgery, who co-developed and implanted the first mechanical heart assist device as a successful bridge-to-transplant in a patient at Stanford.
Advances in immunosuppression agents have shown to be associated with significant outcomes improvement, including the introduction of cyclosporine given to heart transplant patients at Stanford Health Care. Stanford surgeons were the first in the world to use cyclosporine in heart transplantation.
"After the introduction of cyclosporine, there was a marked difference in patient survival rates," said Oyer, co-author on the paper. "This changed the entire face of transplantation, in heart and other organ systems."
For a data repository in heart transplants, Stanford's records provided a comprehensive overview of heart transplantation from a single center dating back more than 50 years. By comparison, other heart transplant registries captured data up to about 30 years back.
"This study provided an extensive overview of the natural history of heart transplantation at Stanford and allowed us to understand where we were then and where we are now," said Yuanjia Zhu, MD, a resident of the Integrated Cardiothoracic Surgical Training Program in the Department of Cardiothoracic Surgery and lead author of the paper.
To the best of her knowledge, Stanford has one of the highest volume programs in the world, Zhu said. According to the Scientific Registry of Transplant Recipients, Stanford Health Care was among the top high-volume heart transplant programs in the United States and the largest in the Bay Area in 2021.
At Stanford, the number of heart transplants has steadily increased each year. Stanford surgeons performed 92 adult heart transplants in 2021 - a record high from the previous years as well as 11 adult en bloc heart-lung transplants, for a total of 103 hearts implanted. A recent report showed heart transplant patients at Stanford had a one year survival at 93%, compared with the national average of 91%.
As one of the top high-volume heart transplant centers in the United States, Stanford’s increasing experience in heart transplantation has demonstrated long-term success for the heart transplant program and outcomes improvement.
Heart transplants at Stanford
Stanford has a long tradition of pioneering heart procedures, including the first adult heart transplant in the United States and the world's first heart-lung transplant. Recently, Stanford surgeons successfully performed one of the world's first multi-organ transplants in a patient whose lungs and kidneys were damaged by COVID-19.
"Stanford surgeons have built its deep experience in heart transplantation that has generated excellent outcomes observed in this study and continue to do so," said Woo. "Patients who come to Stanford are often extremely sick and have complicated cases – our outstanding surgeons, nurses, and health care team members ensure they receive the best care and outcome."
While the findings remain unclear in the exact factors contributing to improved patient outcomes, the study offers insights into one of the largest heart transplantation programs in the United States on what has changed over time in heart transplantation.
The researchers are currently conducting other studies to look into the study implications with a goal to improve patient outcomes.
Additional authors on the paper included Yasuhiro Shudo, MD, PhD, clinical assistant professor of cardiothoracic surgery; Kiah Williams, MD, resident in cardiothoracic surgery; Bharathi Lingala, statistical programmer; Michael Baiocchi, PhD, assistant professor of epidemiology and population health; Veronica Toro Arana, a medical student in Stanford School of Medicine.
The paper was published in European Heart Journal.