The effect of off-pump coronary artery bypass grafting on platelet activation in patients on aspirin therapy until surgery day

Abstract

Objective: Antiplatelet therapy is a class I indication in perioperative care after coronary artery bypass grafting to prevent graft occlusion. We sought to determine whether continuation of aspirin until surgery day suppresses platelet activity in the early period after off-pump coronary artery bypass grafting (OPCAB). Material and methods: Forty-two patients at mean age of 62.5 (±7.9) years were included. Average risk rate (EuroScore logistic) was 2.2 (±1.7) %. In all patients collagen/epinephrine stimulated platelet plug formation (closure time, CT) (CEPI-CT, s) using a platelet function analyzer (PFA-100), troponin I (TnI), creatine kinase-MB (CK-MB), ST segment elevation were evaluated a day before surgery, 4 h after chest closure, 24 and 120 h after surgery. Results: Preoperative mean CEPI-CT was 224.8 (±79.7) s. In 13 (30%) patients aspirin resistance (CEPI-CT < 163 s.) was observed. In 4, 24 and 120 h time points CEPI-CT was significantly reduced: 164.4 (±79), 168.5 (±83.3) and 167.5 (±80.4), respectively (p < 0,001). TnI and CK-MB (ng/ml) levels raised in respective time points: 4 h (0.26 range 4; 1.9 range 6), 24 h (0.2 range 6; 2.6 range 8), 120 h (0.04 range 2; 0.6 range 5). ST segment elevation (mV) changed in time: 4 h (0.7 range 3.5), 48 h (0.7 range 2.8) and 120 h after surgery (0.2 range 1.5). There were no significant correlations between CEPI-CT and TnI, CK-MB, ST segment elevation found. Conclusion: Aspirin therapy continued until surgery day does not protect against acute platelet activation in patients after OPCAB. © 2008 European Association for Cardio-Thoracic Surgery.