Tuesday September 4th
New Study Looks Set to Reduce Harm for Older Patients Facing Heart Surgery
A surprising finding from a major international study involving hundreds of New Zealanders, looks set to reduce major
side effects including death among older patients facing cardiac surgery, as well as conserve the use of a precious and
expensive resource … donated blood.
Published in the prestigious New England Journal of Medicine, the study has shown that using lesser amounts of
transfused blood in older patients undergoing cardiac surgery is not only just as safe, but actually safer than using
more liberal amounts.
One of the study’s lead investigators, Auckland Hospital Intensive Care Specialist Dr Shay McGuinness, says the new
findings go against what, until now, has been international accepted best practice for surgical teams operating on older
patients having open heart surgery.
“Prior to this study it was accepted wisdom that older patients need to be transfused to a higher haemoglobin level
because it was thought their body’s physiology and ability to cope with the stresses of surgery made them less able to
tolerate lower levels than younger patients” says Dr McGuinness.
“The results from this new study, which follows patients six months after their surgery, clearly show that using less
transfused blood during and after heart surgery actually lowers the patient’s subsequent risk of heart attack, stroke,
kidney failure and death” he says.
The randomised study, the world’s largest ever transfusion trial in cardiac surgery, was carried out on over 5200
patients at 74 hospitals in 19 counties. It included more than 560 patients from Auckland City, Waikato, Wellington,
Christchurch and Dunedin hospitals. New Zealand supplied the second highest number of patients for the trial.
Some moderate-to-high risk heart surgery patients were given a liberal blood transfusion strategy while others were
given a lesser, more restrictive strategy. For every 28 patients aged 75 years or older treated with a restricted blood
transfusion strategy, one patient was prevented from experiencing a major complication up to six months post-surgery.
Study co-author Dr Paul Young, from Wellington’s Medical Research Institute of New Zealand (MRINZ) says these findings
will change clinical practice around the world in terms of when and how much blood needs to be given during and after
“Not giving a blood transfusion until an older patient’s haemoglobin measurement is as low as 65% of normal, while once
considered risky, now appears to be just as safe if not safer than giving blood more liberally” says Dr Young. “This
means many who would have been transfused in the past will no longer require it at all, and patients who previously
required several units of blood may now only require one”.
Researchers say these results have one other significant implication for the health system….one with the potential to
conserve a precious and expensive resource.
“If these research findings are adopted into every day practice then not only will they result in better health outcomes
for older patients but also major savings for health systems in the use of less donated blood for transfusion” says Dr
McGuinness. “This is important as cardiac surgery uses significant amounts of donated blood in theatre”.
NZ Blood Service spokesperson and Transfusion Medicine Specialist Dr Richard Charlewood agrees.
“As our population ages and we do more and more cardiac surgery on a growing number of older patients, a reduction in
the use of blood may help to ease the pressure on both donors and the blood service, where donors are finding it
difficult to make time to donate” says Dr Charlewood.
The Health Research Council-backed study is the very first completed by the New Zealand Improving Outcomes After Cardiac
Surgery Network – a new programme within the Medical Research Institute of New Zealand (MRINZ) which brings together
cardiac surgeons, anaesthetists, Intensive Care Specialists, nursing and support staff.
“The next step now is to develop robust guidelines to determine exactly when we should use transfusions for older people
having cardiac surgery” says Dr McGuinness.