Author + information
- Richard H. Hongo, MD and
- Jill Ley, RN, MS, CCRN
We are pleased that Dr. Akowuah and colleagues found our study (1)of interest. We acknowledge the inherent limitations of the study design, and we reiterate that further studies are needed to better define the role of clopidogrel before coronary artery bypass grafting (CABG) surgery. We believe it premature, however, to dismiss the credibility of the main outcomes of this study based on the lack of blinding. Chest tube output, the main measure of postoperative bleeding, is a highly objective and straightforward measurement. Because the nurses who recorded the amount of drainage were not aware of the questions being evaluated by the study, we have no reason to believe there was motive for misrepresentation. Reoperation for bleeding, the main clinical outcome, although a more subjective end point, was directed by institutional clinical guidelines. Patients went for reoperation when chest tube outputs either exceeded 300 ml over 2 consecutive h, or 500 ml over 1 h. As seen in Figure 1 of our study (1), patients with clopidogrel exposure who underwent reoperation all had 24-h chest tube outputs in excess of 4,000 ml, notably more than that of other patients.
The concern raised by Dr. Akowuah and colleagues regarding the use of antifibrinolytic agents is an important one. In our study, aprotinin was administered to eight patients (13.6%) exposed to clopidogrel and one patient (0.6%) without exposure. Any hemostatic effect of this agent would be expected to reduce adverse bleeding outcomes in the clopidogrel group, thus diminishing the differences seen between the groups. Ever since the completion of our study, we have started to use aprotinin routinely when immediate surgery is unavoidable in patients with clopidogrel exposure, and we are finding that perioperative bleeding is substantially reduced in most, but not all, cases. We echo the sentiment that the role of preoperative antiplatelet therapy in combination with antifibrinolytic agents is promising, but it is a role that is still undefined. Until further studies establish the efficacy of aggressive preoperative antiplatelet therapy, we maintain that caution should be exercised when patients exposed to a combination of clopidogrel and aspirin present for CABG surgery.
- American College of Cardiology Foundation