Cardiac transplantation currently is the most effective therapy for end-stage heart failure. Since the origination of the standard biatrial technique, alternative methods such as the bicaval and "total" techniques have been devised with the hope of improving postoperative physiologic and clinical parameters. In general, the newer techniques are at least as effective as the original technique with respect to arrhythmia, valvular function, hemodynamics, exercise capacity, and survival, but whether any one technique offers clear benefits over another has been controversial. The bicaval technique is most commonly used today, and the general consensus is that this technique ultimately will demonstrate clinical superiority.

Animals↗

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Mechanical support for acutely failed heart or lung grafts.

Heart and lung allograft dysfunction continues to be a problem in thoracic transplantation. Although medical therapy is often sufficient to restore allograft function, occasionally more invasive means are required. Mechanical assist devices, inhaled nitric oxide (iNO), and extracorporeal membrane oxygenation (ECMO) have been used with a modest degree of success in cases of refractory heart, lung, and heart-lung allograft failure. Allograft failure secondary to pulmonary hypertension often responds to iNO concentrations between 5 and 70 ppm without major toxicity. More severe cases may require mechanical assist devices or ECMO and carry higher risks of complications such as bleeding, neurological injury, and death. Utilization of and weaning from these interventions require intensive monitoring. Randomized, prospective studies are not ethically feasible, but case reports and patient series indicate the usefulness of mechanical circulatory support, iNO, and ECMO. This review focuses on the indications, complications, and patient survival rates associated with these modalities.

Assisted Circulation↗

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Human plasma causes rapid dysfunction in ex vivo pig hearts.

The use of hearts from large domestic animals represents a potential solution to the current human donor shortage. However, xenogeneic hyperacute graft rejection remains a major barrier to xenotransplantation. The purpose of this study was to use an ex vivo preparation to study variables that may correlate with hyperacute rejection in cardiac xenografts. Freshly excised hearts from 37 anesthetized pigs (10 to 37 kg) were perfused at 37 degrees C through the aorta with retrograde flow. The hearts functioned in a nonworking mode for 4 hours or until irreversible cardiac dysfunction occurred. Various perfusates were used: fresh whole autologous pig blood (n = 4), dog blood (n = 3), baboon blood (n = 5), human packed red blood cells (n = 2), human whole blood (n = 10), human whole blood and plasma (n = 3), and human plasma (n = 9), to which a modified Krebs-Henseleit bicarbonate buffer solution was added. Rapid loss of function was uniform and occurred most quickly (13 to 18 minutes) for hearts perfused with dog blood and human plasma. Isolated cardiac perfusion provided a means for the analysis of the cellular and plasma components of human blood to define which were required for rapid loss of function. The results indicated that the reaction was mediated by components present only in plasma.

Acute Disease↗

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Long-term results of combined heart-lung transplantation: the Stanford experience.

We assessed the long-term results of our experience with 109 patients with end-stage cardiopulmonary disease who underwent primary combined heart-lung transplantation at Stanford University Medical Center between March 1981 and January 1994. Average recipient age was 31 +/- 10 years (mean +/- standard deviation) median, 31 years; range, 1 month to 52 years. Recipient diagnoses included primary pulmonary hypertension (31%), Eisenmenger's syndrome (39%), complex congenital heart disease (8%), cystic fibrosis (14%), bronchiectasis (2%), and emphysema (3%). Immunosuppression was with cyclosporine and a tapering regimen of corticosteroids. In 1986 azathioprine was added, and since 1987 induction therapy with OKT3 has been employed. Actuarial survival rates at 1, 5, and 10 years were 68% +/- 4.6%, 43% +/- 5.4%, and 23% +/- 8.1%, respectively (mean +/- 1 standard error of the mean). Fourteen deaths occurred in the hospital for an operative mortality rate of 12.8% +/- 3.3%, and 61 deaths occurred overall. Causes of death included hemorrhage (five patients), infection (21), rejection (one), nonspecific pulmonary failure (four), graft coronary artery disease (six), and obliterative bronchiolitis (eight). Infection, rejection, and obliterative bronchiolitis were the major complications. Only 20% +/- 3.9% of patients were free from any infection 3 months after transplantation. Heart and lung rejection commonly occurred asynchronously; actuarial estimates of freedom from isolated lung rejection at 1 and 5 years were 47% +/- 5.2% and 40% +/- 5.6%, respectively. For simultaneous heart and lung rejection these estimates were 87% +/- 3.5% and 86% +/- 3.8%, and for isolated heart rejection 63% +/- 5.1% and 51% +/- 6.4%, respectively. Although graft coronary artery disease developed less frequently than in patients after isolated heart transplantation (90% +/- 4.6% of patients were free of graft coronary artery disease at 5 years), obliterative bronchiolitis remains a major long-term complication and cause of morbidity and mortality. Actuarial estimates of freedom from obliterative bronchiolitis at 1, 5, and 10 years were 71% +/- 5.1%, 51% +/- 6.1%, and 42% +/- 7.8%, respectively. These results show satisfactory early and medium-term outcome after combined heart-lung transplantation but also underscore that much progress is needed in controlling infection, rejection, and obliterative bronchiolitis, all of which remain as major impediments to long-term survival.

Actuarial Analysis↗

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Leflunomide prolongs pulmonary allograft and xenograft survival.

BACKGROUND: Leflunomide, an isoxazole derivative, has been shown to effectively prolong rodent allograft and cardiac xenograft survival. In vitro studies suggest that leflunomide inhibits the production of donor-specific antibodies and is capable of blocking both T- and B-cell proliferation. In light of the significant role that humoral immunity is believed to play in chronic pulmonary allograft rejection as well as hyperacute and accelerated acute xenograft rejection, we examined the efficacy of leflunomide in prolonging pulmonary allografts and xenografts and its effect on donor-specific antibody production. METHODS: Lungs from Brown Norway rats or Golden Syrian hamsters were orthotopically transplanted into Lewis rat recipients. Allograft recipients were treated daily for 14 days with vehicle, leflunomide (15 mg/kg/day orally), or cyclosporine (7.5 mg/kg/day orally) starting on the day of grafting (day 0). In xenograft recipients, leflunomide (20 mg/kg/day orally) or cyclosporine (7.5 mg/kg/day orally) treatment initiated on day 0 was continued until complete graft rejection; the leflunomide dosage was reduced to 10 mg/kg/day after day 14 because of weight loss and leukopenia. Graft viability was assessed with chest radiography in conjunction with open lung biopsies. Toxicity was monitored with body weight measurements, complete blood counts, and serum chemistries. Flow cytometric analysis of serum samples taken from graft recipients on day 7 was used to measure donor-specific immunoglobulin M and immunoglobulin G antibody titers. RESULTS: Allograft and xenograft control animals receiving vehicle yielded graft survival times of 6.0 +/- 0.0 and 5.4 +/- 0.6 days, respectively. Although xenograft recipients treated with cyclosporine (7.5 mg/kg/day orally) showed no significant graft prolongation, pulmonary allograft survival in recipients receiving cyclosporine alone was significantly prolonged to 28.2 +/- 0.7 days. Leflunomide-treated allograft (15 mg/kg/day orally) and xenograft (20 mg/kg/day orally) recipients displayed significant graft prolongation to 28.2 +/- 0.7 days and 15.8 +/- 3.3 days, respectively. Cyclosporine (7.5 mg/kg/day orally) enhanced the effect of leflunomide (20 mg/kg/day orally) in xenograft recipients with a mean graft survival time of 36.0 +/- 3.0 days achieved when both drugs were administered concomitantly. Cyclosporine significantly suppressed donor-specific immunoglobulin G antibody titers in both pulmonary allograft and xenograft recipients while not affecting immunoglobulin M levels. Leflunomide markedly suppressed both immunoglobulin G and immunoglobulin M donor-specific antibody titers in allograft and xenograft recipients. Except for mild leukopenia and anemia, both cyclosporine- and leflunomide-treated allograft recipients showed no evidence of toxic side effects after 14 days of therapy. However, leflunomide-treated xenograft recipients displayed significant weight loss, anemia, and leukopenia after 14 days of treatment with one death in each treatment group.

Administration, Oral↗

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Heart retransplantation: the 25-year experience at a single institution.

BACKGROUND: The current critical shortage of cardiac allograft donors means that the decision to offer a patient repeat heart transplantation must be carefully considered. Since 1968, a total of 66 heart retransplantation procedures (63 first-time and three second-time) have been performed in 63 patients at Stanford. METHODS: There were 52 male and 11 female patients, ranging in age from 3 to 62 years with a mean age of 41 years. Indications for retransplantation were primary allograft failure in nine patients, acute rejection in 17, graft atherosclerosis in 37, and constrictive disease in three. Six of the seventeen patients (35%) who underwent retransplantation before 1981 died in the hospital, and none are currently alive. Of the 46 patients who underwent retransplantation since 1981 treated with cyclosporine-based immunosuppression, 11 (24%) died in the hospital. Actuarial survival estimates for the whole retransplantation group at 1, 5, and 10 years were 55% +/- 8%, 33% +/- 8%, and 22% +/- 7%, respectively. RESULTS: This survival was significantly worse (p < 0.05) than that in patients undergoing primary heart transplantation (81% +/- 2%, 62% +/- 2%, 44% +/- 13% at 1, 5, and 10 years). Those patients who underwent retransplantation for graft atherosclerosis since 1981 had a significantly better 1-year survival (p < 0.05) than those who underwent retransplantation for allograft rejection (69% +/- 10% versus 33% +/- 16%), but the 5-year survival was similar in both groups (34% +/- 11% versus 33% +/- 16%). Since 1981, actuarial freedoms from infection and rejection were 22% +/- 8% and 41% +/- 9%, respectively, at 1 year, and 7% +/- 7% and 36% +/- 9% at 5 years. Patients with cyclosporine-induced renal dysfunction (serum creatinine level of greater than 2.0 mg/dl) had a high probability of requiring postoperative dialysis and also of death after retransplantation. Three patients with significant cyclosporine-induced renal dysfunction underwent simultaneous kidney transplantation and heart retransplantation, and all were alive and well at the time this article was written. Sixteen patients were also currently alive at a mean follow-up of 44 months, and 15 were in New York Heart Association functional class I. CONCLUSIONS: We continue to list carefully selected candidates with good rehabilitation potential for heart retransplantation.

Actuarial Analysis↗