The ATACAS Trial
Aspirin and Tranexamic Acid for Coronary Artery Surgery Trial
Principal Investigator: Prof. Paul Myles MB.BS, MPH, MD, FCARCSI, FANZCA
Director, Dept. of Anaesthesia & Perioperative Medicine, Alfred Hospital
There are more than 20,000 heart surgery cases done each year in Australia. About 5% (1,000 patients) have a serious complication or die; this adds substantially to healthcare costs. For example, in the US complications after heart surgery cost more than $15 billion per year.
Cardiac surgery
activates blood cells (platelets) and clotting factors, but also blood clot
breakdown pathways. Excessive bleeding and a need for blood transfusion are
common placing the patient at an increased risk of serious complications.
Patients treated with
aspirin (which is common in those needing heart surgery) have increased
bleeding during and after surgery. Thus
it is routine practice in most cardiac surgical centres around the world for
aspirin to be stopped about one week before surgery.
Another
drug, tranexamic acid, is sometimes used to reduce bleeding after heart
surgery. It works by blocking the clot
breakdown that occurs early after heart surgery. This reduces bleeding, and the
need for a blood transfusion. Importantly,
there is some published information to suggest it is particularly effective in
patients on aspirin. But we do not know whether
or not tranexamic acid increases the risk of thrombosis (heart attack,
stroke).
At this
stage, we are uncertain as to whether it is better to stop aspirin before heart
surgery (to prevent bleeding), continue aspirin (to prevent thrombosis), or to
use tranexamic acid (to prevent bleeding).
There are no large trials to guide our practice.
The ATACAS
Trial has been established to answer a clinically important question: Should
aspirin or tranexamic acid (TA), or both, be used in people having heart bypass
surgery?
Research Plan Synopsis: Design: Large, multi-centre, prospective, randomised, double blind, factorial trial. Patients will be randomly allocated to aspirin, TA, aspirin + TA, or placebo. Primary End Point: A composite endpoint including 30-day mortality or major ischaemic morbidity (myocardial infarction, stroke, pulmonary embolism, renal failure, bowel infarction). Secondary End Points: Each of the above, plus blood transfusion, re-operation, respiratory failure, serious wound infection, prolonged hospitalisation. Sample size: 4600 patients (alpha 0.05, beta 0.10), to detect a 30% (or greater) reduction in major complications or death. Outcomes & Significance: There are some compelling reasons to question the routine stopping of aspirin before elective CABG surgery. Although preoperative aspirin may increase bleeding, it may also reduce MI, other complications and death. TA prevents excessive bleeding and is likely to have other benefits. When considering the cost and extent of CABG surgery in Australia and around the world, small differences in outcome would have major implications for healthcare delivery. |
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If you would like further information or would like to enquire about being a site investigator please contact the Trials Group or email: atacas@admin.org.au
You can also find more information on the ATACAS Website www.atacas.org.au
The ATACAS Trial is a collaborative trial being conducted by the ANZCA Trials Group and the Australian NHMRC Centre of Clinical Research Excellence in Therapeutics
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