The role of nuclear cardiology procedures in the evaluation of cardiac function following heart transplantation

Heart transplantation is, today, an accepted and recommended modality in the management of selected patients suffering from terminal heart disease. However, acute rejection and infection remain the major complications of this operation. Serial endomyocardial biopsy (EB), considered as the standard for diagnosis of cardiac rejection, is an invasive and delicate operation, not free of complications, even when done by skilled personnel in specialized centers. The object of this study was to compare and correlate between radionuclide ventriculography (RNV) and the histologic findings of EB. Furthermore, to validate the use of nuclear cardiology techniques that allow noninvasive, reliable, and rapid quantitation of ventricular function and myocardial perfusion for the diagnosis and management of rejection in patients with heart transplants. Radionuclide studies of left ventricular function were performed in 3 heterotopic heart transplant patients (HHT) with long term survival and early after the operation in 5 patients with HHT, 12 orthotopic heart transplants (OHT) and in 2 heart and lung transplants (HLT). Simultaneous EBs were performed in the early posttransplant patients and a histologic score for acute rejection was obtained. First pass (FP) and multigated equilibrium blood pool ventriculography, using the in vivo 99mTc-labelling of RBCs was used to measure left ventricular volumes (LVV) such as stroke volume (SV), end-diastolic volume (EDV), end-systolic volume (ESV), and both global and regional ejection fraction (EF, REF). The histological grading of acute rejection was classified into four groups: (1) no rejection, (2) mild rejection, (3) moderate rejection, and (4) severe rejection. The median of each LVV parameter was calculated and correlated with the EB using a nonparametric one way analysis of variance. A percentage change of LVVs was used rather than the difference of the calculated LVVs. During moderate acute rejection, SV had the highest correlation in P less than 0.004, followed by the EDV (P less than 0.05), and finally ESV (P less than 0.02). During severe acute rejection the correlation was SV (P less than 0.0008), EDV (P less than 0.001), and ESV (P less than 0.006). Myocardial perfusion scintigraphy using 201T1 was performed in the HHT patients, although, at this stage we have not attempted a correlation with the histologic findings. In one patient with long term survival OHT, increased 131I-metaiodobenzylguanidine (MIBG) myocardial uptake was evident during a rejection episode.

The effects of denervation and acute rejection on left ventricular volumes measured by radionuclide ventriculography following cardiac transplantation in the chacma baboon

Seven baboons underwent autotransplantation of the heart or heart and both lungs (group A). Eleven allografts were performed (group B) (nine orthotopic heart transplants and two en bloc transplants of the heart and both lungs). Radionuclide ventriculography was performed both pretransplant and at intervals posttransplant in all animals, and provided measurements of ejection fraction (EF) and left ventricular volumes (LVv) (end-diastolic volume [EDV], end-systolic volume [ESV], and stroke volume [SV]). In seven animals, a total of 20 endomyocardial biopsies were taken. Correlation was made between histopathological features of acute rejection seen on endomyocardial biopsy and changes in EF and LVv measured by radionuclide imaging. A significant increase of 12% in the EF (P less than 0.01) and significant falls in the LVv were observed in all animals (groups A and B) on the first posttransplant day, presumably a result of total cardiac denervation. EDV was reduced by 50% (P less than 0.005), ESV by 62% (P less than 0.0001), and SV by 43% (P less than 0.0001). In autografted baboons (group A) EF and LVv showed no further changes until reinnervation of the heart had occurred, when they reverted to pretransplant levels. In the allografted baboons (group B) further significant reductions in the LVv occurred as acute cardiac rejection progressed. From the first post-transplant day to the time of the final study before the animals' death, the EF decreased by 10% (P less than 0.01), the EDV by 38% (P less than 0.005), and SV by 73% (P less than 0.003): the decrease in ESV did not reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Injury of myocardial conduction tissue and coronary artery smooth muscle following brain death in the baboon

Experimental brain death was induced in 36 chacma baboons. In group A (n = 17), brain death was induced with no pharmacologic or surgical manipulation. Group B (n = 7) underwent bilateral vagotomy, unilateral left cardiac sympathectomy, or bilateral adrenalectomy before induction of brain death. Group C (n = 7) underwent total cardiac sympathectomy. Group D (n = 5) was pretreated with verapamil hydrochloride. Following induction of brain death, group A animals were maintained on a ventilator for a mean of 12 hr and 6 hr for the remaining groups. At the end of the experiment, the heart was excised, and tissue blocks were examined with light microscopy at (A) the atriaventricular node-bundle of His; (B) the major coronary arteries; and (C) myocardial tissue from the ventricular septum or left ventricular wall. In group A, 41% of the hearts showed histologic features of injury to the conduction tissue, 70% presented contraction band necrosis of the smooth muscle of the coronary arteries, and an incidence of 100% of the groups showed myocyte injury, more evident in the subendocardial area. In group B animals, conduction tissue injury was seen in 6 animals; the coronary arteries were not examined in this group; the incidence of myocyte injury was seen in 80% of the animals. Animals in groups C and D show no histopathologic injury in the conduction tissue (group A vs. C P less than 0.04), nor in the coronary arteries (group A vs. C P less than 0.002; group A vs. D P less than 0.01), preserving the myocytes (P less than 0.001). The catecholamine storm associated to acute increment of the endocranial pressure at the time of induction of brain death induces major histopathologic changes in the myocardium, as a result of endogenous catecholamines released inducing calcium overflow injury, affecting the conduction tissue, the smooth muscle of the coronary arteries, and the contractile myocardium. This can be prevented by calcium blockers or cardiac denervation.

Inotropic effect of triiodothyronine following myocardial ischemia and cardiopulmonary bypass: an experimental study in pigs

A significant reduction (p less than 0.0001) in plasma-free triiodothyronine (T3), which is known to have an inotropic effect, has been documented in patients undergoing open-heart procedures. To investigate the effect of this observation, 22 pigs underwent 2 hours (Group 1, r = 10) or 3 hours (Group 2, r = 12) of myocardial ischemia during cardiopulmonary bypass (CPB) at 26 degrees C; the myocardium was protected by cardioplegic solution and cold saline solution at 30-minute intervals. After the pig was rewarmed to 37 degrees C, CPB was discontinued, and measurements of hemodynamic function were made 10 and 70 minutes later. Half of the pigs (Subgroup B) received 6 micrograms of T3 intravenously immediately after removal of the aortic cross-clamp; the remainder (Subgroup A) received no T3. After 2 hours of ischemia, untreated pigs showed significantly reduced myocardial function 10 minutes after discontinuation of CPB. By 70 minutes after the end of CPB, 2 of 5 untreated pigs (Subgroup A) had died of low cardiac output, but all 5 treated pigs (Subgroup B) survived. After 3 hours of ischemia, both groups showed some reduced function at 10 minutes, though the reduction was more marked in untreated animals. By 70 minutes, 4 of 6 untreated pigs had died of myocardial failure and all treated pigs remained alive (p less than 0.03). Surviving pigs in both groups still demonstrated some reduced function compared with values obtained before CPB. When all pigs are considered together, overall survival of those that did not receive T3 was significantly less than those that did (p less than 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

Change from aerobic to anaerobic metabolism after brain death, and reversal following triiodothyronine therapy

Brain-dead organ donors are depleted of circulating triiodothyronine (T3) and show features suggestive generally of anaerobic metabolism at the tissue level, accompanied by deteriorating hemodynamic function. The principle of single-bolus kinetics with labeled carbon compounds (14C-R), with subsequent measurement of both plasma activity and of exhaled 14C O2 has therefore been used to study glucose, pyruvate, and palmitate utilization under conditions of (1) sedation, (2) brain death, and (3) brain death with T3 therapy in the baboon. Serum lactate and plasma-free fatty acid concentrations were also measured. There was a major change in metabolic oxidative processes following brain death. The rate of glucose, pyruvate, and palmitate utilization was markedly reduced, and there was an accumulation of lactate and free fatty acids in the plasma, indicating a general change from aerobic to anaerobic metabolism. The administration of T3 to the brain-dead baboon resulted in a dramatic increase in the rate of metabolite utilization, and a reduction in the plasma concentrations of plasma lactate and free fatty acids, indicating an apparent reversal from tissue anaerobic to aerobic metabolism. We suggest that T3 should be administered to all brain-dead potential organ donors to correct and maintain a more physiologic metabolic status and thus to improve organ function.

Initial experience with heart and lung transplantation

Between February 1983 and July 1987, twelve patients underwent heart-lung transplantation at the University of Cape Town and the University of Munich. The patients included eight men and four women, whose ages ranged from 15 to 49 years (mean, 27 years). The underlying pathologic condition was idiopathic primary pulmonary hypertension in five cases, Eisenmenger's syndrome in four cases, idiopathic pulmonary fibrosis in one case, diffuse fibrosing alveolitis in one case, and chronic emphysema in one case. The immunosuppressive regimen consisted of cyclosporine A, azathioprine, and rabbit antithymocyte globulin (RATG) during the first 2 postoperative weeks; RATG was subsequently replaced by methylprednisolone. Pulmonary rejection frequently occurred in the absence of cardiac rejection; in one case, however, this situation was reversed. Two patients required retransplantation, which was undertaken for caseating pulmonary tuberculosis with obliterative bronchiolitis after 1 year in one case and for early pulmonary insufficiency after 2 days in the other case. There were no operative deaths, but three early deaths occurred, owing to respiratory insufficiency of unknown origin (10 days postoperatively), multiorgan failure (10 days postoperatively), and acute liver dystrophy (11 days postoperatively). Five weeks after operation, a fourth patient died of multi-organ failure. There were five late deaths, all of which resulted from infectious complications. Three patients, including one who underwent retransplantation, remain alive and well, 10 to 36 months postoperatively.

Heart transplantation at Groote Schuur Hospital, Cape Town. Twenty years' experience

Human allogeneic heart transplantation was started at Groote Schuur Hospital in Cape Town in 1967. Since then 110 hearts (61 heterotopic and 49 orthotopic) and 12 heart-lung transplantations have been performed in the unit. Ten procedures were retransplantations including 2 third interventions. The patients fall into three groups according to their immunosuppressive therapy: group A (N = 55) from 1967 to 1982 received the so-called 'conventional treatment' (azathioprine, methylprednisolone and antithymocyte globulin (ATG)); group B (N = 15) from 1983 to 1984 received cyclosporin A in high dosage, together with methylprednisolone; and group C (N = 30) received quadruple drug therapy of low-dose cyclosporin A, together with azathioprine, methylprednisolone in lower dosages and antithymocyte globulin (for the first 4-6 days and rescue-ATG for severe rejection). The results have improved significantly over the years. The actuarial survival rate after heart transplantation within the last 12 months is 94%. Several important steps have been inaugurated: in 1973 heterotopic heart transplantation was initiated and in 1984 hormonal therapy of brain-dead organ donors was started. Radionuclide scanning, in combination with endomyocardial biopsies, has proved to be a very sensitive means of monitoring rejection.

Twenty years of heart transplantation at Groote Schuur Hospital

Between December 1967 and July 1987, 110 heart transplantations (61 heterotopic and 49 orthotopic) and 12 heart-lung transplantations were done at Groote Schuur Hospital in Cape Town, South Africa. Twelve procedures were retransplantations, including two third interventions. The patients were divided into three groups: Group A (n = 55) from 1967 to 1982 received so-called conventional treatment of azathioprine, methylprednisolone, and antithymocyte globulin. Group B (n = 15) from 1983 to 1984 had cyclosporine in high dosages together with methylprednisolone. Group C (n = 30) received quadruple drug therapy of low-dosage cyclosporine, together with azathioprine, methylprednisolone in lower dosages, and antithymocyte globulin (for the first 4 to 6 days and rescue antithymocyte globulin for severe rejection). From Group A, nine of 55 patients are alive up to 17 years after transplantation. The main causes of death were acute rejections and infections (in 60% altogether). From group B, six of 15 patients are alive. Acute rejections and infections were the causes of death in 12% of the patients, but multiple organ failure was a major cause in 24% most probably because of the high dosages of cyclosporine. From group C, 23 of 30 patients have survived. In this group the results after heterotopic heart transplantation do not differ significantly from orthotopic transplantation, which justifies this procedure in particular situations. If all heterotopic and orthotopic transplantations are compared, orthotopic procedures have a substantially better outcome. With the modified immunosuppressive regimen (group C) combined with precise donor and recipient selection and more sophisticated rejection monitoring, the actuarial survival rate within the last 12 months is 94%.

Is pulmonary ischemia a factor in the reperfusion response? An experimental study in the chacma baboon

A reimplantation or reperfusion response has been described in both the experimental animal and the human patient after various procedures involving pulmonary ischemia. We have investigated this phenomenon in a primate model. Ten chacma baboons were placed on cardiopulmonary bypass and cooled to 20 degrees C. Circumferential segments of the right main bronchus and pulmonary artery were denuded of all surrounding tissue. Each structure was then cross-clamped, which rendered the lung ischemic, during which time the organ was immersed in cold saline solution. Ischemia was maintained for 1.5 to 5 hours; after reperfusion and discontinuation of bypass, the right lung was biopsied and the chest closed. Chest radiographs, lung biopsies, and arterial blood gases were taken at intervals for up to 16 to 28 days. Right lung shadowing on chest radiography with concomitant histopathologic changes, indicative of a reperfusion reaction, were seen in only one animal, which had undergone lung ischemia for 1.5 hours. In one other animal that was ischemic for 5 hours, patchy opacification of the lung was seen on two occasions (days 8 and 15) with concomitant mild histopathologic changes. In conclusion, therefore, a major reperfusion response after pulmonary ischemia in the chacma baboon is possible but unusual. This would suggest that the appearance of pulmonary opacification on chest radiography within the first 4 weeks after heart-lung transplantation in humans is most likely attributable to some other condition, such as isolated lung rejection or infection.

Hemodynamic and metabolic responses to hormonal therapy in brain-dead potential organ donors

An evaluation of the beneficial effects of hormonal therapy, consisting of T3 2 micrograms, cortisol 100 mg, and insulin 20 units, administered at hourly intervals intravenously, was assessed in brain-dead patients referred for organ donation. Twenty-six conventionally treated donors (group A) showed a progressive hemodynamic deterioration requiring significant increments of inotropic support in order to maintain cardiovascular stability, necessitating a significant increase in bicarbonate requirements in order to maintain a normal acid-base balance. Of this group, 20% of the donors were considered unsuitable as cardiac donors due to progressive cardiovascular deterioration or sudden ventricular fibrillation. Hormonal therapy was administered to 21 donors (group B) resulting in a significant improvement of cardiovascular status, requiring less inotropic support and significantly less bicarbonate. A significant reduction of serum lactate-pyruvate followed the initiation of the hormonal therapy. In group B, organs from all donors (heart, heart and lungs, and kidneys) were suitable for transplantation, with excellent organ function following implantation of the graft.

Pathophysiology of pulmonary edema following experimental brain death in the chacma baboon

Systemic and pulmonary hemodynamics have been studied during the induction of brain death in the chacma baboon. In 11 animals brain death was induced by acute intracranial hypertension. Continuous recording of blood flow through both the pulmonary artery and the aorta was obtained by electromagnetic flow meters placed around these vessels. Mean arterial, central venous, pulmonary arterial, and left atrial pressures were recorded continuously. Systemic and pulmonary vascular resistances were calculated. During the agonal period marked sympathetic activity occurred, with significant increases in circulating catecholamines and systemic vascular resistance. The great increase in systemic resistance resulted in acute left ventricular failure. Mean left atrial or pulmonary capillary wedge pressure rose above the mean pulmonary arterial pressure in 9 animals. As the systemic vascular resistance rose, a significant difference between pulmonary artery and aortic blood flows occurred, leading to blood pooling within the lungs. A mean of 72% of the total blood volume of the animal accumulated within these organs. The increase of left atrial pressure to levels higher than pulmonary artery pressure indicated a state of pulmonary capillary blood flow arrest. This, associated with the blood pooling within the lungs, almost certainly resulted in disruption of the anatomic integrity of the pulmonary capillaries (blast injury); 4 animals developed pulmonary edema, with alveolar septal interstitial hemorrhage.

Improved cardiac function following hormonal therapy in brain dead pigs: relevance to organ donation

Deterioration of function in brain dead baboons is associated with depletion of both myocardial energy stores and certain circulating hormones, notably thyroxine, cortisol, and insulin. We have therefore investigated the effect of the administration of these three hormones to the brain dead pig; their value has been assessed on both the freshly excised and stored donor heart. Brain death was induced by ligation of the two arteries to the upper part of the body which arise from the aortic arch. Storage of selected hearts was by continuous hypothermic perfusion for 20 to 24 hr. Hearts were biopsied for estimation of adenosine triphosphate, creatine phosphate, lactate, and glycogen, and were subsequently functionally tested. Six groups of pigs were studied. Hearts were tested from control pigs which had not undergone brain death (A1), from brain dead pigs which had received intravenous fluid and inotropic support for 4 hr (B1), and from brain dead pigs which had in addition received 2 hr of hormonal therapy (thyroxine 2 micrograms cortisol 100 mg, and insulin 5-10 IU hourly) (C1). A further 3 groups (A2-C2) underwent management identical to A1-C1, but in addition the hearts were stored for 24 hr. Brain death in pigs was followed by a consumption of myocardial energy stores, despite anaerobic glycolysis; this was associated with reduced myocardial function. The administration of hormones to the brain dead pig led to some replenishment of myocardial energy and glycogen reserves and reduction in lactate, with associated improvement in hemodynamic function. A period of hypothermic perfusion storage appeared to reverse the anaerobic metabolism occurring in the heart in the nonhormonally treated brain dead animal, though not in the hormonally treated animal, and led to replenishment of glycogen reserves in nontreated animals. The observation that both better function and an increase in myocardial energy stores occurred in hormonally treated, stored hearts, even though perfusate lactate dehydrogenase rose to significantly higher levels during hypothermic perfusion storage, and tissue lactate levels remained high, suggests that thyroxine promotes both aerobic and anaerobic metabolism in brain dead animals.

Successful orthotopic heart-lung transplantation in the baboon after five hours of cold ischemia with cardioplegia and Collins' solution

En bloc transplantation of the heart and lungs was performed in 15 chacma baboons; the donor organs were stored between 4 and 6 hours before transplantation. The hearts were perfused in the donor animals with 15 ml/kg Wicomb's cardioplegic solution at 4 degrees C, the lungs with either 20 ml/kg 4 degrees C Collins' solution with an added 2.5% dextrose and 12 mEq magnesium sulfate (Collins' solution, group 1, n = 8), Collins' solution plus superoxide dismutase (40,000 U/L superoxide dismutase, group 2, n = 4), or Collins' solution plus superoxide dismutase plus peroxidase (5000 U/L peroxidase plus mannitol, group 3, n = 3). The pulmonary artery perfusion pressure was not allowed to exceed 50 cm water; the lungs were maintained at 30% to 50% inflation, and external cooling was applied. After explantation the thoracic organs were stored in 0.9% saline solution at 4 degrees C. In groups 1 (Collins' solution) and 2 (Collins' plus superoxide dismutase) all surviving baboons revealed normal blood gas values and normal light and electron microscopic histology at 24 hours. Three animals had further biopsies at intervals between 1 and 9 days, at which time the histology of the lungs proved normal and well preserved. All three baboons in group 3 (Collins' plus superoxide dismutase plus peroxidase) had grossly abnormal blood gas values from the time of operation, and all died within 9 hours; light microscopy of the lungs showed early lung infarctlike lesions and in one case pulmonary edema. These preclinical findings proved that storage of the lungs in Collins' solution with or without superoxide dismutase is possible for up to 5 hours; the addition of peroxidase had a detrimental effect.

Prevention of myocardial injury by pretreatment with verapamil hydrochloride prior to experimental brain death: efficacy in a baboon model

Systemic and pulmonary hemodynamics were studied in two groups of Chacma baboons following the induction of brain death. Group A was a control group of 11 animals who underwent brain death. They showed significant increments of mean systemic arterial, left atrial, and pulmonary arterial pressures; of systemic vascular resistance, heart rate, and pulmonary artery blood flow; and a reduction in aortic blood flow during the induction of brain death. As a result of increased sympathetic nervous system activity, areas of myocardial cell necrosis occurred in 73% of the animals and pulmonary edema in 36%. Group B consisted of five animals that were pretreated with verapamil hydrochloride infused over a period of 30 minutes prior to the induction of brain death (mean dosage, 0.26 mg/kg). Except for a rise in heart rate, no significant changes occurred in systemic or pulmonary hemodynamics, and no myocardial or pulmonary histopathological changes were seen. These findings would indicate that verapamil hydrochloride prevents both the peripheral and central hemodynamic changes that result from increased sympathetic activity associated with the induction of brain death, and thus prevents myocardial structural damage, which may be associated with increased calcium uptake by the myocyte.

Loss of myocardial viability following hypothermic perfusion storage from contaminating trace elements in the perfusate

Two groups (A and B) of isolated baboon hearts were preserved by continuous hypothermic perfusion storage for 48 hours using perfusates that, according to the manufacturers, differed only in the concentrations of the contaminating trace elements iron, lead, and arsenic. Storage with the perfusate containing the higher concentration of these elements (perfusate B) led to significantly less gain in heart mass, a greater reduction in coronary flow, coronary sinus effluent lactate, and myocardial arteriovenous oxygen difference and a greater increase in coronary sinus effluent lactate dehydrogenase, when compared with perfusate A. Group B hearts totally failed to support the circulation following orthotopic transplantation, whereas group A hearts showed excellent function. Group B hearts had undergone the typical changes of enhanced resting myocardial tension during the storage period (before warm blood reperfusion); we proposed that these changes were brought about by the production of superoxide anions and radicals by the higher relative concentration of iron, or a combination of contaminating trace elements, in perfusate B. To confirm that these perfusates did differ significantly in the concentration of these trace elements, in particular with regard to iron, the superoxide anion activity in both solutions was measured and was found to be significantly higher in perfusate B. The addition of superoxide dismutase to both solutions inhibited superoxide anion activity by more than 80%.

Interpretation of endomyocardial biopsy after heart transplantation. Potentially confusing factors

Histological examination of the myocardium by endomyocardial biopsy is a standard method of monitoring the presence of acute rejection in the transplanted heart. The histopathological consequences of the biopsy procedure itself have been investigated in non-transplanted hearts in the baboon. Organization of thrombus, necrosis of myocytes adjacent to the biopsy site, and mononuclear cells (including T lymphocytes) surrounding the biopsy site appear after biopsy; should a subsequent biopsy be taken from this area, these appearances may be confused with the appearances associated with acute or resolving cardiac rejection. This problem has been encountered in the clinical transplant programme. Observations on the myocardial histopathological changes resulting from brain death and from parasitic infestation, both of which may also lead to confusion in the interpretation of endomyocardial biopsies, are also presented. Awareness of these factors in patients with heart transplants should lead to caution in the interpretation of the histopathological features and may avoid unnecessary extra immunosuppression early after transplantation. Observations indicate that endomyocardial biopsy should not be the sole method of monitoring for the development of acute rejection.

Regression of Kaposi's sarcoma after reduction of immunosuppressive therapy in a heart transplant patient

The de novo development of Kaposi's sarcoma, confirmed by lymph node biopsy 17 months after heart transplantation in an 18-year-old patient, is described. Constitutional symptoms and axillary and inguinal lymphadenopathy were the presenting features. Surveillance for systemic involvement was negative, and the tumor seemed to be confined to the lymphoreticular system alone. Chemotherapy with vincristine and cyclophosphamide resulted in severe leukopenia and was discontinued. Immunosuppressive therapy, consisting of cyclosporine and methylprednisolone, was gradually reduced, resulting in regression of symptoms and lymphadenopathy. One year later the patient was symptom free, and only one extremely small inguinal lymph node was palpable. Microscopic examination of this node, however, revealed persistent Kaposi's sarcoma. The patient's immunosuppressed state would now appear to be sufficient to prevent acute rejection and yet insufficient to lead to growth and spread of the tumor.

Are there indications for heterotopic heart transplantation in 1986? A 2- to 11-year follow-up of 49 consecutive patients undergoing heterotopic heart transplantation

In the 9-year period between November 1974 and December 1983, 49 patients underwent heterotopic heart transplantation at Groote Schuur Hospital. Eight patients subsequently underwent a further transplant procedure, and one of these a third transplant (58 transplants in 49 patients). Conventional immunosuppressive therapy (azathioprine, corticosteroids, and rabbit antithymocyte globulin) was used in 47 cases (81%), and cyclosporine and conventional immunosuppression in 11 (19%). Follow-up (to 1st January 1986) has been for a minimum of 2 and a possible maximum of 11 years. Forty-one of the 49 patients (85%) have subsequently died, mean survival of this group being 18.5 months. Mean survival of the 8 patients alive is 74 months. One-year survival has been 55% and 5-year survival 22%. In light of this experience, it would seem to us that the indications for heterotopic transplantation have now greatly diminished. There would still appear to be a place for it, however, when the donor heart is small in relation to the mass of the recipient, when there is a possibility of myocardial recovery following the resolution of a myocarditis, and when there is an elevated pulmonary vascular resistance which may make orthotopic transplantation hazardous. Heterotopic heart transplantation may also be indicated when the recipient circulation is failing rapidly despite maximal medical support, and therefore transplantation is urgent.

Surgery in patients with heart transplants. Anaesthetic and operative considerations

As cardiac transplantation becomes more common, so an increasing number of patients with functioning heart transplants may require surgery for related or unrelated non-cardiac conditions. Fifteen patients who have undergone a total of 39 operations (excluding retransplantation) since heart transplantation were reviewed; 36% were for infective conditions and 23% each for gastro-intestinal and vascular lesions. There was one postoperative death in a patient undergoing leg amputation for overwhelming Clostridium welchii infection. There were no major non-fatal complications. The conditions for which operation may be necessary, the specific problems of anaesthesia and surgery in such patients, and the prophylactic measures which may be undertaken to ensure an uncomplicated clinical course are discussed. A clear understanding of the physiology and pharmacology of the denervated heart is essential if these patients are successfully to undergo major operations requiring general anaesthesia.