The number of patients with heart failure is growing, as a consequence in the improvement in management of several cardiovascular diseases and the change in longevity of the population, as well as improved survival of heart failure patients. The incidence is estimated to be around 1%. Despite the advances in early diagnosis and treatment of cardiovascular diseases, including drugs and devices, the mortality in end stage heart failure is very high. Since the first human heart transplant performed in South Africa by Christian Barnard in 1967, the science of human transplantation has been changing. In the two last decades the heart transplant has evolved of a purely experimental procedure until becoming an effective therapeutic option for many patients with end stage cardiomyopathies. Improvement in treatment of patients with heart failure, better donor management, changes in surgical technique, better organ preservation, advances in the field of immunosuppression, initially with the introduction of cyclosporine as the main immunosuppressive agent and actually with other drugs like tacrolimus, everolimus, and mycophenolate and induction therapy significantly improved survival. In the last report of the Registry of the International Society for Heart and Lung Transplantation the transplant half-life, the time at which 50% of those transplanted remain alive, for the entire cohort is currently 10 years, with a half life of 13 years for those surviving the first year.
It is calculated between 10 to 40 procedures by millions of inhabitants per year to cover completely the indication of heart transplantation in a population. Heart failure is the main cause of death in 40.000 patients and contributes to this one in other 250,000 cases every year in the United States; nevertheless of the population of patients who potentially would benefit from a heart transplant, about 25,000, only 2.500 patients are undergoing of this procedure, around of 10%. This situation is explained for multiple reasons, in developed countries the most important is the limitation in the availability of donors, but in underdeveloped countries, like ours, there are a very limited waiting list and many donor’s heart are not utilized. In some cases patients with heart failure never know the benefit of this type of procedures, limiting his probability of survival.
Other interesting finding in the last report is the changing in characteristics of the most recent cohort. The primary indication for adult heart transplantation was non-coronary cardiomyopathy, the percentage of recipients aged 60 years has increased whereas the percentage of recipients 40 to 49 years of age has continued decline, 41% percent were receiving inotropic support and 29% were on mechanical support, only 44% percent of patients were hospitalized before the transplant and the percentage of patients with a panel reactive antibody (PRA) > 10% has increased from 5% to 12.4%.
It is calculated between 10 to 40 procedures by millions of inhabitants per year to cover completely the indication of heart transplantation in a population. Heart failure is the main cause of death in 40.000 patients and contributes to this one in other 250,000 cases every year in the United States; nevertheless of the population of patients who potentially would benefit from a heart transplant, about 25,000, only 2.500 patients are undergoing of this procedure, around of 10%. This situation is explained for multiple reasons, in developed countries the most important is the limitation in the availability of donors, but in underdeveloped countries, like ours, there are a very limited waiting list and many donor’s heart are not utilized. In some cases patients with heart failure never know the benefit of this type of procedures, limiting his probability of survival.
Other interesting finding in the last report is the changing in characteristics of the most recent cohort. The primary indication for adult heart transplantation was non-coronary cardiomyopathy, the percentage of recipients aged 60 years has increased whereas the percentage of recipients 40 to 49 years of age has continued decline, 41% percent were receiving inotropic support and 29% were on mechanical support, only 44% percent of patients were hospitalized before the transplant and the percentage of patients with a panel reactive antibody (PRA) > 10% has increased from 5% to 12.4%.
Current Indications
Patients should only be considered for transplantation when they are on optimal therapy. The optimal non-pharmacological and pharmacological therapy include follow-up in a heart failure clinic, considering several therapies such as cardiac resynchronization therapy, implantable cardioverter defibrillator, coronary revascularization therapy, alternative surgical options and others. The decision to accept a patient for heart transplantation is made after a strict clinical evaluation by a cardiologist with broad experience in this topic, and of course by a transplantation team. The general experience is that the patients with clear indications are never referred, the majority of patients referred for transplantation are never listed and that those who are listed are rarely listed immediately after referral. It is important to evaluate the prognosis in an individual patient, although it is extremely difficult because of the variability of the clinical course of heart failure.
Criteria for Cardiac Transplantation
Accepted
High risk by Heart Failure Survival Score (HFSS)
Very low peak VO2 after reaching anaerobic threshold
NYHA class III-IV refractory to maximum therapy
Severe myocardial ischemia non-susceptible of revascularization therapy
Severe ventricular arrhythmia refractory to medical, surgical and ICD treatment
Probable
HFSS intermediate risk
Low peak VO2 and severe functional limitation
Instability of fluid status and renal function despite of adherence, daily weight, restriction of liquids and salt and flexible diuretics.
Recurrent unstable ischemia non-susceptible of revascularization therapy
Inadequate
HFSS low risk
Peak VO2 > 14 ml/kg/min without another indication
Low Left Ventricular ejection fraction
History of NYHA class III/IV
History of ventricular arrhythmias
Peak oxygen consumptionPatients with peak VO2 ≥ 14 ml/kg/min have 94% survival at one year follow-up. Patients with peak VO2 of 10-14 ml/kg will be insisted on medical treatment and reevaluate according to its evolution.Patients with peak VO2 less than 10 ml/Kg/min or less than 50% of predicted for age and gender during anaerobic exercise (respiratory quotient, RQ more than 1.05) are considered a clear indication of the procedure. In addition to peak VO2, it is important to consider others variables like VE/VCO2 slope during exercise more than 35, the VE/VCO2 slope/ pVO2 ratio more than 2.51 and peak systolic arterial pressure less than 120 mmHg.
Algorithm for Heart Transplantation.
Heart Failure Survival ScoreAlgorithm for Heart Transplantation.
The Heart Failure Survival Score (HFSS) predict risk in heart failure patients. Additionally, patients with a predicted high risk of dying by HFSS are the only group that has a survival benefit of transplantation.
Heart Failure Survival Score
High Risk ≤ 7.19, medium risk 7.2-8.09 and low risk ≥ 8.10. Event free survival rates at 1 year for the low, medium and high risk HFSS strata are 93 ± 2%, 72 ± 5% and 43 ± 7%, respectively.
See video of a Heart Transplant Procedure.
See video of a Heart Transplant Procedure.
References
1. JACC 2004;43;787-793
2. Circulation 1997;95:2660-2667
3. Heart 2002;87;177-184
4. Netherlands Heart Journal 2008;16 Number 3
5. J Heart Lung Transplant 2006; 25:1003–23.
6. J Heart Lung Transplant 2008; 27:943–56.
7. JACC 2008; 52:587–98
2. Circulation 1997;95:2660-2667
3. Heart 2002;87;177-184
4. Netherlands Heart Journal 2008;16 Number 3
5. J Heart Lung Transplant 2006; 25:1003–23.
6. J Heart Lung Transplant 2008; 27:943–56.
7. JACC 2008; 52:587–98
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