Pediatric Heart Transplantation
in Canada
By Helen Holtby MBBS FRCPC
Interim Head, Cardiac Anaesthesia Division
Labbatt Family Heart Centre
Sickkids Hospital
Toronto
Pediatric heart transplantation in Canada is undertaken in five centres in four cities and both official languages (French and English). Montreal has two centers, Montreal Children’s Hospital and Hopital Ste Justine. Canada has the largest land mass with a relatively low population of 34.5 million, 90% of whom live within 100km of the 49th parallel. This is 6,000 km from west to east. Transplants are done in Vancouver, Edmonton, Toronto and Montreal. The issues of geography and population mean that families with a child with serious heart disease often face separation, considerable travel and other expenses. It also means that the budget and logistics for organ retrieval are considerable.
The first pediatric heart transplant worldwide was in 1967 on a neonate with Ebsteins anomaly who survived six hrs. After a 20 year hiatus, and with improvements in all areas of care, the first heart transplant at the Hospital for Sick Children in Toronto occurred in 1990. Toronto and Edmonton currently have the largest volumes of transplants in Canada, and perform 10-20 procedures each, per year. A major Canadian contribution to the field of pediatric heart transplantation (and more recently, lung transplantation) has been the successful, intentional use of ABO incompatible organs.
The intentional transplant of an ABO incompatible heart was performed at Sickkids Hospital, Toronto, in the late 1990s, based on work done by Dr Lori West’s group (Dr West is now Canada Research Chair in Cardiac Transplantation, The University of Alberta). Young infants demonstrate low levels of anti-A and anti-B isohemagglutinins and therefore are tolerant of “incompatible” organs. The upper age limit or the upper limit of acceptable titres is not known. However, in the largest single centre cohort the outcomes are indistinguishable from ABO compatible transplants for children under 14 months. This has considerable implications for anesthesiologists looking after patients having ABO mismatched transplants, or in subsequent surgeries. It is necessary to do a plasma exchange in the recipients, which is routinely done, going on to cardiopulmonary bypass, with intra-operative measurement of isohemagglutinins. We have found the simplest and most efficient way to proceed is to prime the pump with appropriate blood products and an expanded prime volume, and divert the recipient’s blood volume into the cell saver going onto bypass. The diversion of circulating volume, and ongoing plasmapheresis can be continued during cardiopulmonary bypass depending on the titres.
There is a lifetime requirement for appropriate organ-matched blood products as outlined in the table below. It is imperative that parents and the patient understand their unique needs and can communicate this to outside hospitals and treating physicians.
Anesthesiologists caring for children who will undergo heart transplantation face multiple challenges, from adverse physiology and low cardiac output, to difficult vascular access, management of drug interactions, and understanding the limitations of mechanical support devices. The children often face depression loneliness, exaggerated pain and stress responses which the acute intervention of an operative procedure can exacerbate. Post-transplantation presents its own challenges and an awareness of the subtleties of graft vasculopathy is useful. We have had several children present with peri-procedural cardiac arrest.
At present, it is routine for all children who are being listed for heart transplantation to have an anaesthesia consultation to identify any specific issues and to discuss the operative plan with the patient and the family. A significant number of patients have cardiomyopathy, and no prior cardiac surgery so need to be informed about the relevant procedures. Post-transplant patients who need general anaesthesia are triaged by the transplant service and the cardiac anaesthesia division for appropriate care.
Blood Transfusion Requirement for ABO Incompatible Heart Transplant Patients
Recipient Group |
Donor |
PRBC |
FP |
Cryo |
Platelets |
O |
A |
O |
A |
A |
A/AB (O or B conc) |
O |
B |
O |
B |
B |
B/AB (O or A conc) |
O |
AB |
O |
AB |
AB/A/B |
AB (Aor B conc then O conc) |
A |
B |
A |
AB |
AB/B |
AB (B conc then A or O conc) |
A |
AB |
A |
AB |
AB/A/B |
AB (A or B conc then O conc) |
B |
A |
B |
AB |
AB/A |
AB (A conc then B or O conc) |
B |
AB |
B |
AB |
AB/A/B |
AB (A or B conc) |
References:
- Daly KP,et al; Pediatric Heart Transplant Study Investigators. Sudden death after pediatric heart transplantation: analysis of data from the Pediatric Heart Transplant Study Group. J Heart Lung Transplant. 2011 Dec;30(12):1395-402.
- Benden C,et al,; International Society of Heart and Lung Transplantation. The Registry of the International Society for Heart and Lung Transplantation: fifteenth pediatric lung and heart-lung transplantation report--2012. J Heart Lung Transplant. 2012 Oct;31(10):1087-95.
- Dipchand AI,et al; Equivalent outcomes for pediatric heart transplantation recipients: ABO-bloodgroup incompatible versus ABO-compatible. Am J Transplant. 2010 Feb;10(2):389-97.doi: 10.1111/j.1600-6143.2009.02934.x. Epub 2009 Dec 23. PubMed PMID: 20041867.
- West LJ, et al; ABO-incompatible heart transplantation in infants. The New England Journal of Medicine, 344(11) 793-800.
