The Future of Heart Transplantation

Abstract

The field of heart transplantation has seen significant progress in the past 40 years. However, the breakthroughs in long-term outcome have seen stagnation in the past decade. Through advances in genomics and transcriptomics, there is hope that an era of personalized transplant therapy lies in the future. To see where heart transplantation truly fits into the long term, searching for and understanding the alternative approaches for heart failure therapy is both important and inevitable. The application of mechanical circulatory support has contributed to the largest advancement in treatment of end stage heart failure. It has already been approved for destination therapy of heart failure, and greater portability and ease of use of the device will be the future trend. Although it is still not prime time for stem cell therapy, clinical experiences have already suggested its potential therapeutic effects. And finally, whole organ engineering is on the horizon as new techniques have opened the way for this to proceed. In the end, progress on alternative therapies largely depends on our deeper understanding of the mechanisms of heart failure and how to prevent it.

Heart Transplantation: Challenges Facing the Field

“…A greater proportion of patients in their sixties and seventies along with their age-related comorbidities are being transplanted. These patients tend to have higher risks of infection and CAV (Kobashigawa 2012). At the other end of the spectrum, advances in congenital heart surgery have led to a greater proportion of younger patients with congenital heart disease (CHD) surviving past childhood and developing heart failure later in life.…”

“…Some barriers are well known, such as (1) the shortage of donor organs, which greatly limits the number of patients able to receive a heart transplant; (2) cardiac allograft vasculopathy (CAV) and malignancy, which compromise the long-term survival of heart transplant recipients; and (3) drug-induced complications from chronic immunosuppression including diabetes mellitus, kidney disease, hypertension, and obesity, which contribute to patient morbidity and mortality. Other challenges, such as increasingly complicated recipients and antibody-mediated rejection (AMR), have only become evident over the last decade as the recipient demographics have changed and the use of mechanical circulatory support (MSC) devices has increased (Hunt and Haddad 2008; Kobashigawa 2012). Together, these obstacles account for the fact that there has been no increase in the number of adult heart transplants performed over the last decade (~4000 documented worldwide transplants/year) despite almost a 20% increase in the number of new adults on the waiting list (Colvin-Adams et al 2013) and the fact that the 5-yr survival of patients lucky enough to receive a heart is still only ~70%, with a disappointing median survival of 11 yr and an annual attrition rate of 3%–4%, which has not changed significantly in the last three decades (Stehlik et al 2012; Colvin-Adams et al 2013).…”

Destination therapy: the new gold standard treatment for heart failure patients with left ventricular assist devices

“…4 SynCardia spokesperson Don Isaacs says that the FDA has approved HUD designation for both its 70cc and 50cc TAHs to be used for destination therapy. Currently, patients with the TAH can be discharged home with the much lighter weighing freedom driver system," from SynCardia.…”

The future of cardiac transplantation

“…These rates have remained relatively (25,26) and are perhaps the larger instigators. The innate immune response is also suspected of mediating graft injury (27). Some have even theorized that ischemiareperfusion injury at the time of donor procurement alters gene expression, resulting in a rejection-susceptible protein milieu (28,29).…”