Tranexamic acid role in coronary bypass surgery

Mar 7 2013

By Eleanor McDermid, Senior medwireNews Reporter

Tranexamic acid balances the increased bleeding risk associated with recent clopidogrel use in patients undergoing on-pump coronary artery bypass grafting (CABG), shows a randomized trial.

The benefits occurred even if patients had used clopidogrel in the 7 days prior to surgery, report Lihuan Li (Peking Union Medical College, Beijing, China) and colleagues in JAMA Surgery.

Before being randomly allocated to receive tranexamic acid or placebo, the 552 patients in the study were stratified according to whether they had taken clopidogrel during the 7 days before surgery, had discontinued it earlier, or had never taken it. Average blood loss during surgery rose in line with clopidogrel exposure, at 993, 1107, and 1262 mL with no exposure, discontinued exposure, and recent exposure, respectively. The corresponding rates of blood transfusion were 63.4%, 70.1%, and 81.3%.

Treating patients with tranexamic acid during surgery (10 mg/kg bolus followed by 10 mg/kg per hour maintenance) significantly attenuated the effect of clopidogrel, with an average blood loss of 959 mL versus 1237 mL with placebo for the three groups combined, and transfusion rates of 60.6% versus 79.5%.

Moreover, the effect seemed greatest among patients who had recently taken clopidogrel, with tranexamic acid treatment associated with a 366 mL reduction in blood loss and a 16.2 percentage-point reduction in transfusion rate. This was similar to the effect seen in patients with no clopidogrel exposure, but larger than in those with discontinued exposure, at a 170 mL reduction in blood loss and a 12.6 percentage-point reduction in transfusion rate.

There were no significant differences between the groups for in-hospital mortality or morbidity, or for 1-year mortality.

"In light of the current study, the interval between the cessation [of clopidogrel] and the operation is no longer a major determinant of the bleeding and transfusion outcomes in these patients and routine cessation of clopidogrel may not be necessary with the presence of antifibrinolytics, especially in urgent cases and patients with high thrombotic risk," say Li et al.

However, writing in an accompanying critique, Nauder Faraday (Johns Hopkins University School of Medicine, Baltimore, Maryland, USA) urges skepticism with respect to this claim, pointing out that exposure to clopidogrel was not randomly assigned.

"Although it certainly may be reasonable to continue dual antiplatelet therapy in some individuals at particularly high thrombotic risk prior to CABG," the current study "does not provide robust evidence on this issue," he says. "Adherence to current consensus recommendations seems more prudent."

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