A national survey of Canadian surgeons by researchers at McMaster University found little consistency in their use of the blood thinner ASA in patients undergoing non-cardiac surgery.
To resolve the issue, Canadian surgeons say they would welcome a randomized controlled trial, and allow their patients to participate in it, said Dr. Rajesh Hiralal, who led the survey and is presenting its results today in Vancouver at the annual meeting of the Canadian Society of Cardiac Surgeons.
The findings are significant because non-cardiac surgery, such as hip replacements and cancer surgery, makes up 95 per cent of all surgery performed today and the numbers are growing. Cardiac surgery accounts for less than five per cent.
Close to 100 million adults world-wide -- and half a million Canadians - undergoes major non-cardiac surgery annually. Globally, upwards of one million of these patients go on to suffer a non-fatal heart attack, non-fatal cardiac arrest or death as a result of their surgery, said Dr. Hiralal.
"One of the great tragedies is that despite the advances we've had in surgeries and anaesthesia, we have people potentially getting cures of their cancer, or a new hip, with a new lease on life, who either may die around the time of surgery because of heart complications or they may have a non-fatal event which can actually take their life three to six months later," said Dr. P.J. Devereaux, one of 15 McMaster researchers who undertook the survey.
As a blood thinner, ASA provides potential protection from the development of blood clots following surgery. However, most studies on its use have been conducted on patients undergoing cardiac surgery. There has never been a large trial to address whether or not ASA is effective for non-cardiac surgery.
To get a reading on current practices around the use of ASA, McMaster researchers sent a questionnaire to 1,850 Canadian surgeons who are members of the Canadian Orthopedic Association, the Canadian Association of General Surgeons and the Canadian Society of Vascular Surgery. More than 900 responded.
They found "marked variability" in practice between the three surgical specialties.
"Among surgeons in general there is a lot of practice variation in how they are managing ASA at the time of surgery," said Dr. Devereaux. "They are doing very different things and there is no consistency. They are uncertain if there is a real benefit and if that benefit outweighs the risk, even if there is, in fact, a risk."
The McMaster researchers represented a multi-disciplinary group of specialists in cardiology, anaesthesia and surgery as well as intensivists and internists.
Dr. Rajesh Hiralal can be reached today in Vancouver by cell phone.
Materials provided by McMaster University. Note: Content may be edited for style and length.
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