Cardiac Transplantation

Chapter 29


Cardiac Transplantation





1. How many heart transplantations are performed in the U.S. each year? What are the most frequent causes of heart disease requiring cardiac transplantation?


    Dr. Christiaan Barnard performed the first human allograft transplantation in 1967. Approximately 2000 to 2200 hearts are currently transplanted each year, most commonly for nonischemic cardiomyopathy (46%) and coronary artery disease (40%), as well as for congenital heart disease, valvular heart disease, and other indications, including retransplantation.


2. List common indications for heart transplantation.



image Severe heart failure (New York Heart Association [NYHA] class III or IV) with poor short-term prognosis despite maximal medical therapy, requiring continuous inotropic therapy, requiring mechanical support (e.g., balloon pump, left ventricular assist device [LVAD], extracorporeal membrane oxygenation [ECMO])


image Restrictive or hypertrophic cardiomyopathy with NYHA class III or IV symptoms


image Refractory angina despite medical therapy, not amenable to revascularization, with poor short-term prognosis


image Recurrent or refractory ventricular arrhythmias, despite medical and/or device therapy


image Complex congenital heart disease with progressive ventricular failure not amenable to surgical or percutaneous repair


image Unresectable low-grade tumors confined to the myocardium, without evidence of metastasis


3. What baseline evaluations are obtained in the pretransplantation workup?


    Pretransplantation evaluation serves the purpose of assessing a patient’s severity of heart failure, mortality benefit from surgery, comorbidities, and potential contraindications to surgery. Factors important in transplantation evaluation are given in Box 29-1.



4. What are contraindications to heart transplantation?


    Contraindications include any noncardiac conditions that may decrease a patient’s survival, and increase risk of rejection or infection, and are listed in Box 29-2.



5. Define allotransplantation versus xenotransplantation, and orthotopic versus heterotopic transplantation.


    Allotransplantation involves transplantation of cells, tissue, or organs between same species Xenotransplantation involves transplantation of cells, tissue, or organs between different species. During orthotopic heart transplantation, the donor heart is transplanted in place of the recipient’s heart. There are two anastomotic approaches used (Fig. 29-1).




During heterotopic heart transplantation, the recipient’s heart is left in the mediastinum, and the donor heart is attached “parallel” to the recipient heart (see Fig. 29-1).


6. Define ischemic time of the donor heart. Why is it important?


    The cold ischemic time is the time interval between removal of the donor heart and the implantation in the recipient. During this interval, ischemic injury can occur to the heart due to lack of perfusion. Myocardial preservation is achieved with hypothermia and placement of the heart in a solution mimicking intracellular milieu to prevent cellular edema and/or acidosis, and maintain ATP supply for membrane function. A prolonged ischemic time can lead to irreversible damage to the harvested organ. A cold ischemic time of more than 5 hours is associated with a higher incidence of cardiac allograft dysfunction and decreased transplant recipient survival.


7. What is the estimated graft survival at 1 year, 3 years, 5 years, and 10 years posttransplantation? What are the common causes of death?


    Based on the 2007 U.S. Organ Procurement and Transplantation Network (OPTN) and Scientific Registry of Transplant Recipients (SRTR) report, graft survival approximates 88% at 1 year, 73% at 5 years, and 50% at 10 years posttransplantation.


    The major causes of death posttransplantation are as follows:



8. What is cardiac allograft vasculopathy (CAV)? Describe its pathophysiology, incidence, risk factors, and outcome.


    Also known as transplant vasculopathy or transplant coronary artery disease (CAD), CAV is the progressive narrowing of the coronary arteries of the transplanted heart. Angiographic incidence of CAV is approximately 30% at 5 years and 50% at 10 years. CAV is associated with a significantly increased risk of death. After the first year posttransplantation, CAV is the second most common cause of death (after malignancy). In CAV, there is diffuse, concentric proliferation of the intimal smooth muscle cells and it typically involves the entire length of the coronary artery. In contrast, conventional atherosclerosis results from fibrofatty plaque resulting in concentric or eccentric focal lesions. The etiology of CAV remains unclear, but both immunologic (cellular and/or humoral rejection, human leukocyte antigen [HLA] mismatch) and nonimmunologic (cytomegalovirus [CMV] infection, hypercholesterolemia, older age and/or male donors, younger recipients, history of CAD, diabetes mellitus [DM], and insulin resistance) factors have been implicated

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Jun 5, 2016 | Posted by in CARDIOLOGY | Comments Off on Cardiac Transplantation

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