Thoracic
organ transplantation
Heart
transplantation
Dr Christiaan Barnard performed the first human heart transplant in Cape
Town, South Africa, in 1967. The operation was based on the experimental work of
Richard Lower and Norman Shumway in Stanford, and Shumway subsequently went on
to pioneer successful cardiac transplantation in the clinic. Heart
transplantation is now considered an effective treatment for selected patients
with end-stage
Transplantation
is considered only in patients with end-stage heart disease which has failed to
respond to all other conventional therapy and where predicted survival without
transplantation is only 6—12 months. Suitable candidates are New York Heart
Association (NYHA) class III (symptoms on mild exertion) or class IV (unable to
perform any physical activity without discomfort, which may occur at rest).
Transplantation is usually limited to patients under the age of 65 years who
do not have irreversible damage to other organ systems. The preoperative
assessment is rigorous and measurement of pulmonary vascular resistance is
mandatory because when it is raised the perioperative mortality is high.
Technique
of heart transplantation
A median sternotomy is performed and the patient is given systemic
heparin, placed on cardiopulmonary bypass and cooled to 280C. After
cross-clamping the aorta, the recipient heart is excised at the mid-atrial
level. The donor heart is then removed from ice and the left atrium is then
opened by making incisions (Fig. 11.21) in the posterior wall between the
orifices of the pulmonary veins to create an atrial cuff. The left and then
right atrial anastomoses are performed and the aortic and pulmonary arterial
anastomoses are then completed (Fig. 11.22). The patient is then re-warmed and
weaned from cardiopulmonary bypass. Total orthotopic cardiac transplantation is
an alternative but rarely used procedure in which the entire recipient heart is
excised and the donor heart is implanted by caval (superior and inferior),
pulmonary vein (right and left), aorta and pulmonary arterial anastomosis.
Occasionally, heterotopic cardiac transplantation is undertaken where the
donor heart is placed adjacent to and augments the recipient’s own heart.
Heart—lung,
single-lung and double-lung transplantation
Pulmonary transplantation became a clinical reality when Dr Bruce Reitz
performed the first successful combined heart—lung transplant in 1981.
Combined heart—lung transplantation is still sometimes used, especially for
patients with pulmonary vascular disease where there is cardiac dysfunction
due to congenital (e.g. Eisenmenger’s syndrome) or acquired cardiac
dysfunction. For most patients with end-stage pulmonary disease, however,
single- or double-lung transplantation has now replaced heart—lung
transplantation. Lung transplantation is more economical in terms of organ
usage, although if heart—lung transplantation is undertaken for isolated
respiratory disease, the healthy native heart can be used for transplantation
— the so-called ‘domino
Single-
and double-lung transplantation is an effective therapy for selected patients
with end-stage chronic lung disease where declining lung function limits life
expectancy. Suitable candidates typically have NYI-IA class III or IV symptoms
and a life expectancy of less than 2 years despite optimal medical therapy.
Common indications are pulmonary fibrosis, pulmonary hypertension and cystic
fibrosis. Single-lung transplantation is performed for pulmonary fibrosis.
Patients with cystic fibrosis and other forms of septic lung disease require
excision of both native lungs and bilateral or en bloc double-lung
transplantation, because single-lung transplantation results in soiling of the
transplant from the native diseased lung. Single-lung transplantation is
performed through a posterolateral thoracotomy, and double-lung transplantation
through bilateral thoracotomy or median sternotomy. During lung transplantation
the donor pulmonary veins on a left atrial cuff are anastomosed to the recipient
left atrium. Next, the bronchial anastomosis and the pulmonary arterial
anastomosis are completed. Cardiopulmonary bypass is usually required if
pulmonary hypertension is present. Dehiscence of the airway anastomosis used
to be common after heart—lung and lung transplantation but improvements in
organ preservation and surgical technique have dramatically reduced the
incidence of this often fatal complication to < 5 per cent. Late
airway stenosis at the bronchial anastomosis due to ischaemia occurs in around
10 per cent of bronchial anastomoses and is treated by dilatation.
Outcome
after thoracic organ transplantation
One- and 5-year graft survival after heart transplantation is around 85
and 70 per cent, respectively. The results after heart—lung and lung
transplantation are less good with 1-year graft survival rates of around 75 per
cent and 5-year survival rates of around 40 percent.