Dr Tonino Bombardini at the Department of Echocardiography and Medical Informatics, Institute of Clinical Physiology, National Research Council, Pisa, explained: ‘Age-related high prevalence of asymptomatic coronary artery disease and cardiomyopathy severely limit the feasibility of this approach unless a functional screening of the candidate donor heart is performed.
‘Pharmacological stress echo is inexpensive and allows a simultaneous evaluation of inducible ischemia and contractile reserve of the left ventricle. It’s therefore possible to unmask prognostically meaningful occult coronary artery disease or cardiomyopathy.’ However, he stressed the importance of having the donor heart assessed by an experienced operator, who may not always be available at the donor centre. Obtaining that expert’s opinion can be possible by using telecardiology. ‘A second opinion of digitally transferred images of stress echo results could solve the technical variability in selection of aged donor hearts for heart transplantation,’ he said.
Under the Adonhers protocol, when the Transplant Coordination Centre identifies a marginal aged donor, the cardiologist at that location performs rest echocardiography and when that shows as normal, a stress echo. From there, he logs into the Adonhers website, which automatically transfers the reports and images to a central server in Pisa, where, once alerted, the Core Echo Lab Cardiologist interprets the tele-echocardiograms, offers the second opinion and decides whether to proceed with the donation. ‘When done, the second opinion report is sent to the transplant coordination centre and, if the marginal heart is eligible for transplant, it is proposed to the cardiac transplant surgeon,’ said Dr Bombardini.
Italy, like the US and other European countries, is short of donor hearts. About 300 heart transplants (HTs) are performed annually, but 700 patients are on the HT waiting list, with a 10% yearly death rate and a mean 2.5 years waiting list before a transplant.
With around 1,250 consensual donors annually, 270 of whom are aged 55-65 years, Dr Bombardini says recruitment of even a third of the dismissed donor pool would make a significant impact on the current donor shortage.
The International Society of Heart and Lung Transplantation (ISHLT) guidelines for the care of HT recipients recently recommended that donor hearts over 55 years should only be used if the survival benefit of an HT for a recipient unequivocally exceeds the decrement in early HT survival due to transplantation of a heart with limited myocardial reserves.
‘The stress echo-driven selection of hearts may be a possible approach to resolving the mismatch between organ supply and demand,’ Dr Bombardini pointed out.
The Adonhers Project is approved by the Ethical Committee of the Emilia-Romagna Region and Tuscany Region, and has recently been accepted, endorsed and funded by the Italian Health Ministry.
As Scientific Coordinator of the Project, Dr Bombardini said results so far have been significant: ‘From 51 marginal candidate donors, the team found 23 eligible hearts with normal findings. Of these, 19 eligible hearts were uneventfully transplanted in marginal emergency recipients. The recipients’ one-year survival rate was similar to standard younger donor heart (not selected by stress echo) recipients’ one-year survival.’
However, he stressed that further experience is needed in the use of ‘marginal donors’ before exact guidelines can be established with more liberal use of stress echo for donor selection. However, the protocol is now set to be expanded from Pisa across all Italian centres and potentially to other European centres.
The methodology and pilot study results are to be presented at the American Society of Echocardiography meeting in June and have been submitted for presentation at the annual ESC Congress 2011 this August in Paris.