Objectives: To investigate whether point-of-care platelet function testing immediately before coronary artery bypass grafting correlates to postoperative blood loss and transfusion requirements.
Design: Blood samples from 50 patients on antiplatelet therapy were analysed by Plateletworks(®). Thirty-three of the patients had received clopidogrel, 300-600 mg loading dose followed by 75 mg once daily, within 7 days. Postoperative chest drainage volume was recorded every hour.
Results: Plateletworks(®) ADP-induced platelet aggregation correlated significantly to postoperative chest drainage volume at 5 hours (r = -0.83; p < 0.01) and 12 hours (r = -0.55; p < 0.01), and the tertile of patients with the lowest aggregation had higher postoperative transfusion requirements (p < 0.01) and about three times larger chest drainage volume than remaining patients during the first 5 hours after surgery (p < 0.01). Cessation of clopidogrel correlated to chest drainage volume at 5 hours (r = -0.48; p < 0.01) and 12 hours (r = -0.47; p < 0.01) after surgery.
Conclusions: The significant correlation between Plateletworks(®) ADP-induced platelet aggregation and blood loss suggests that this test may be useful to predict risk of excessive bleeding and to guide timing of surgery and bleeding treatment in patients undergoing coronary artery bypass grafting.